首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   186篇
  免费   3篇
  国内免费   1篇
教育   133篇
科学研究   42篇
各国文化   3篇
体育   3篇
信息传播   9篇
  2023年   3篇
  2022年   8篇
  2021年   8篇
  2020年   3篇
  2019年   11篇
  2018年   19篇
  2017年   6篇
  2016年   19篇
  2015年   8篇
  2014年   4篇
  2013年   20篇
  2012年   12篇
  2011年   8篇
  2010年   8篇
  2009年   8篇
  2008年   6篇
  2007年   7篇
  2006年   7篇
  2005年   2篇
  2004年   1篇
  2003年   3篇
  2001年   2篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1982年   2篇
  1979年   2篇
  1978年   1篇
  1975年   2篇
排序方式: 共有190条查询结果,搜索用时 861 毫秒
101.
In basketball, the defender’s reaction to a pass is slower and more error prone if the attacking player gazes into the opposite direction. This so-called head-fake effect might be modulated by context information, that is, the frequency and the sequence of head fakes occurring. Accordingly, the present study investigates the head-fake effect for different frequency proportions (20% vs. 50% vs. 80%). The results show that the head-fake effect decreases when the head fake occurs more often. Furthermore, a potential influence of previous fake experience (i.e., congruency-sequence effect) on the size of the head-fake effect was investigated. Importantly, previous fake experience did not cause the frequency-based modulation of the general size of the head-fake effect. These findings bare important implications for sports practice, especially when it comes to instructing players about the tactical use of deceptive actions.  相似文献   
102.
This paper proposes a fuzzy model predictive control (FMPC) combined with the modified Smith predictor for networked control systems (NCSs). The network delays and data dropouts are problems, which greatly reduce the controller performance. For the proposed controller, the model of the controlled system is identified on-line using the Takagi – Sugeno (T-S) fuzzy models based on the Lyapunov function. There are two internal loops in the proposed structure. The first is the loop around the FMPC, which predicts the future outputs. The other is the loop around the plant to give the error between the system model and the actual plant. The proposed controller is designed for controlling a DC servo system through a wireless network to improve the system response. The practical results based on MATLAB/SIMULINK are established. The practical results are indicated that the proposed controller is able to respond the networked time delay and data dropouts compared to other controllers.  相似文献   
103.
Osteoporosis is a systemic disease with a strong genetic component. Vitamin D receptor (VDR) has been suggested as a candidate gene for osteoporosis. Therefore the present study was aimed to investigate the pattern of allelic variants of VDR gene polymorphism (FokI and BsmI), its influence on vitamin D levels and bone mineral density (BMD) in North Indian postmenopausal women with osteoporosis for possible genetic association. 254 postmenopausal osteoporotic women and 254 postmenopausal non osteoporotic women were included in the study. VDR FokI and BsmI gene polymorphism gene were assessed by the PCR-RFLP method. Serum 25-hydroxyvitamin D was measured by the ELISA. BMD at the L1–L4 lumbar spine, hip, forearm and femoral neck was assessed by dual energy X-ray absorptiometry. The average BMD at spine and hip in postmenopausal women with bb and spine, hip, femoral neck and forearm with ff genotype had significantly low BMD. The frequency of ff genotype and f allele was significantly higher in postmenopausal osteoporotic women when compared with postmenopausal non osteoporotic women. However, no significant association was found between the genotypes and vitamin D levels. Our study reveals that VDR gene FokI and BsmI polymorphism is significantly associated with low bone mineral density. Therefore the ff genotype and f allele of VDR FokI gene may be used as an important risk factor for osteoporosis.  相似文献   
104.
In the present study the antioxidative potential ofMomordica charantia, Azadirachta indica, Allium sativum andOcimum sanctum was assessed in streptozotocin induced diabetic rats. Lipid peroxide levels were also measured in normal, diabetic and treated animals. Malondialdehyde (MDA) levels were significantly higher and antioxidant activity was found low in diabetic groups as compared to the control groups, and significant alteration in both the MDA levels and antioxidant activity was also observed when the above herbal hypoglycemic agents were given to diabetic rats. On the basis of our results we conclude thatM. charantia, A. indica, A. sativum andO. sanctum are not only useful in controlling the lipid peroxide levels but are also helpful in further strengthening the antioxidant potential.  相似文献   
105.
Field experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan, during winter 2003~2004 and 2004~2005 to evaluate the effect of nitrogen and sulfur levels and methods of nitrogen application on canola (Brassica napus L. cv. Bulbul-98) under rainfed conditions. Four levels of S (0, 10, 20, and 30 kg/ha) and three levels of N (40, 60, and 80 kg/ha) and a control treatment with both nutrients at zero level were included in the experiments. Sulfur levels were applied at sowing while N levels were applied by three methods (100% soil application, 90% soil 10% foliar application, and 80% soil 20% foliar application). The experiments were laid out in randomized complete block (RCB) design having four replications. Oil content increased significantly up to 20 kg S/ha but further increase in S level did not enhance oil content. Glucosinolate content increased from 13.6 to 24.6 μmol/g as S rate was increased from 0 to 30 kg/ha. Protein content increased from 22.4% to 23.2% as S rate was increased from 0 to 20 kg/ha. Oil content responded negatively to the increasing N levels. The highest N level resulted in the highest values for protein (23.5%) and glucosinolate (19.9 μmol/g) contents. Methods of N application had no significant impact on any parameters under study.  相似文献   
106.
The phytochrome B (PHYB) gene of Arabidopsis thaliana was introduced into cotton through Agrobacterium tumefaciens. Integration and expression of PHYB gene in cotton plants were confirmed by molecular evidence. Messenger RNA (mRNA) expression in one of the transgenic lines, QCC11, was much higher than those of control and other transgenic lines. Transgenic cotton plants showed more than a two-fold increase in photosynthetic rate and more than a four-fold increase in transpiration rate and stomatal conductance. The increase in photosynthetic rate led to a 46% increase in relative growth rate and an 18% increase in net assimilation rate. Data recorded up to two generations, both in the greenhouse and in the field, revealed that overexpression of Arabidopsis thaliana PHYB gene in transgenic cotton plants resulted in an increase in the production of cotton by improving the cotton plant growth, with 35% more yield. Moreover, the presence of the Arabidopsis thaliana PHYB gene caused pleiotropic effects like semi-dwarfism, decrease in apical dominance, and increase in boll size.  相似文献   
107.
Within medical education a reduction in curriculum time for subjects, such as anatomy puts pressure on educators to ensure the same learning outcomes are conveyed in less time. This has the potential to impact negatively on student experience. Near-peer teaching (NPT) is often praised as an effective revision tool, but its use as a frontline teaching resource remains unreported. The study explores the potential for NPT to promote delivery of learning outcomes and maximize student experience within a neuroanatomy module for second year medical students. The study occurred in three educational settings, (1) frontline NPT of cranial nerves, (2) revision session NPT of cranial nerves, and (3) NPT alongside faculty staff in laboratory-based neuroanatomy practical exercises. For the first and second components, knowledge was measured using a pre- and post-session test and student perception was ascertained with a questionnaire. For the third component, student perception was assessed with an end-of-module survey. The results show that overall, NPT was well received by learners. A significant knowledge gain was seen between the pre- and post-session test of the frontline NPT session. The study presents evidence in favor of using NPTs to supplement the delivery of learning outcomes in a time and resource constrained curriculum. In particular, for the effective delivery of frontline material. Anat Sci Educ 0: 1–9. © 2018 American Association of Anatomists.  相似文献   
108.
Non-Hodgkin’s lymphoma constitutes a group of disorders originating from the malignant transformation of lymphocytes and involving either the lymph nodes or extranodal sites. NHL commonly presents in the sixth to seventh decade of life with a male preponderance (50–75 %). Recent studies have shown importance of serum LDH in prognosis of NHL. Authors report a case of a 63 year old male presenting with complaints of fever and backache for past 4 months. General and systemic examination revealed bilateral axillary lymphadenopathy and splenomegaly respectively. Serum LDH level was highly elevated (3441 U/l). Excisional axillary and bone marrow biopsy were done before oncology referral. Complete workup revealed diffuse Non-Hodgkin’s lymphoma with bone marrow infiltration. Patient died because of acute renal failure due to NHL and DM 2 (Type 2 diabetes mellitus).  相似文献   
109.
This research investigates the effects of socioscientific instruction on pre-service teachers’ sense of efficacy in the teaching and learning of controversial family health issues. For this purpose, a total of 251 students from two teacher training colleges participated in the study and were randomly assigned as experimental and control groups. The experimental group was taught the contents of the controversial family health issues using socioscientific instruction approach and the control group was taught the same content using a more traditional approach. Quantitative data were obtained from both groups after responding to the ‘Teacher sense of Efficacy Scale’ as instrument used for data collection before and after the treatments. Analysis of covariance was used in data analysis of which the pre-treatment scores were used as covariates. Qualitative interviews were conducted with ten participants randomly selected from the experimental group before and after the treatment to deepen and elaborate the quantitative data. The quantitative and qualitative findings indicate that the integration of the socioscientific instruction have significantly affected the pre-service teachers’ sense of efficacy in favour of the experimental group that shows a more stronger sense of efficacy. It was concluded that the socioscientific instruction is significantly effective in changing the pre-service teachers’ weaker sense of efficacy to a stronger one in the controversial family health issues.  相似文献   
110.
Methods of assessment in anatomy vary across medical schools in the United Kingdom (UK) and beyond; common methods include written, spotter, and oral assessment. However, there is limited research evaluating these methods in regards to student performance and perception. The National Undergraduate Neuroanatomy Competition (NUNC) is held annually for medical students throughout the UK. Prior to 2017, the competition asked open-ended questions (OEQ) in the anatomy spotter examination, and in subsequent years also asked single best answer (SBA) questions. The aim of this study is to assess medical students’ performance on, and perception of, SBA and OEQ methods of assessment in a spotter style anatomy examination. Student examination performance was compared between OEQ (2013–2016) and SBA (2017–2020) for overall score and each neuroanatomical subtopic. Additionally, a questionnaire explored students’ perceptions of SBAs. A total of 631 students attended the NUNC in the studied period. The average mark was significantly higher in SBAs compared to OEQs (60.6% vs. 43.1%, P < 0.0001)—this was true for all neuroanatomical subtopics except the cerebellum. Students felt that they performed better on SBA than OEQs, and diencephalon was felt to be the most difficult neuroanatomical subtopic (n = 38, 34.8%). Students perceived SBA questions to be easier than OEQs and performed significantly better on them in a neuroanatomical spotter examination. Further work is needed to ascertain whether this result is replicable throughout anatomy education.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号