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   347篇
  免费   2篇
教育   183篇
科学研究   27篇
各国文化   5篇
体育   91篇
综合类   1篇
文化理论   7篇
信息传播   35篇
  2023年   3篇
  2022年   8篇
  2021年   14篇
  2020年   17篇
  2019年   25篇
  2018年   30篇
  2017年   24篇
  2016年   30篇
  2015年   16篇
  2014年   22篇
  2013年   47篇
  2012年   15篇
  2011年   16篇
  2010年   10篇
  2009年   3篇
  2008年   4篇
  2007年   5篇
  2006年   4篇
  2005年   6篇
  2004年   4篇
  2003年   4篇
  2002年   1篇
  2001年   3篇
  2000年   2篇
  1999年   2篇
  1998年   5篇
  1997年   1篇
  1995年   3篇
  1994年   1篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有349条查询结果,搜索用时 31 毫秒
121.
122.
This paper analyses how knowledge-based practices adopted by innovation intermediaries enable them to generate value for themselves when collaborating with their clients. While the literature focuses on value creation for their client organisations, little is known about how innovation intermediaries create internal value even though this is essential for ensuring their long-term survival and sustaining their key facilitating role in the innovation system. This understudied issue is explored using empirical evidence from a sub-set of innovation intermediaries, Research and Technology Organisations (RTOs). The results indicate that by capitalising on existing knowledge vested in employees and collaborators as well as understanding and shaping the knowledge base of the innovation ecosystem, innovation intermediaries generate internal value from their involvement in collaborative innovation, which range from different financial to non-financial types of value. Implications for intermediaries, their collaborators and for policymakers are then discussed.  相似文献   
123.
In this paper, we propose a numerically robust blind equalization scheme to mitigate cochannel and intersymbol interferences and separate signals from a convolutive mixture in multiple-input multiple-output (MIMO) communication systems. The robustness of the proposed scheme is achieved through a particular dual-mode operation applied to a constant-modulus-based space-time algorithm that corrects phase rotations. In the first mode of operation, the consistency in the nonlinear estimates of the transmitted signals is ensured. In the second mode, the Euclidean norms of the equalizer coefficient vectors decrease along the iterations, which allows the algorithm to return to the first mode of operation, where the estimation of the transmitted signals really occurs. In particular, we apply this scheme to a multimodulus version of the multiuser Shalvi-Weinstein algorithm (MU-SWA). By means of a deterministic stability analysis assuming the persistence of excitation condition, we show that the dual-mode MU-SWA does not diverge.  相似文献   
124.
The aim was to compare the passive drag-gliding underwater by a numerical simulation and an analytical procedure. An Olympic swimmer was scanned by computer tomography and modelled gliding at a 0.75-m depth in the streamlined position. Steady-state computer fluid dynamics (CFD) analyses were performed on Fluent. A set of analytical procedures was selected concurrently. Friction drag (Df), pressure drag (Dpr), total passive drag force (Df+pr) and drag coefficient (CD) were computed between 1.3 and 2.5 m · s?1 by both techniques. Df+pr ranged from 45.44 to 144.06 N with CFD, from 46.03 to 167.06 N with the analytical procedure (differences: from 1.28% to 13.77%). CD ranged between 0.698 and 0.622 by CFD, 0.657 and 0.644 by analytical procedures (differences: 0.40–6.30%). Linear regression models showed a very high association for Df+pr plotted in absolute values (R2 = 0.98) and after log–log transformation (R2 = 0.99). The CD also obtained a very high adjustment for both absolute (R2 = 0.97) and log–log plots (R2 = 0.97). The bias for the Df+pr was 8.37 N and 0.076 N after logarithmic transformation. Df represented between 15.97% and 18.82% of the Df+pr by the CFD, 14.66% and 16.21% by the analytical procedures. Therefore, despite the bias, analytical procedures offer a feasible way of gathering insight on one’s hydrodynamics characteristics.  相似文献   
125.
The present study aimed to determine the effects of physical training performed by parents on mice offspring adiposity. Male and female parents underwent an aerobic training protocol for 7 weeks. The trained and sedentary parents were allowed to mate and the resultant offspring divided in: S (Offspring from Sedentary Parents), T (Offspring from Trained Parents), ST (Offspring from Sedentary Father and Trained Mother) and TS (Offspring from Trained Father and Sedentary Mother). After weaning, offspring was euthanized, blood collected and samples of mesenteric and inguinal fat pads used to isolate adipocytes for morphologic and histological analyses. Lee index, mesenteric fat pad, sum of visceral fat and total fat weight of female T was reduced in comparison to the other groups (p < 0.05). Periepididymal and sum of visceral fat in male T group was also reduced when compared to the other groups (p < 0.05). The diameter of mesenteric and inguinal adipocytes of T group was smaller compared to all groups comparisons for both sexes (p < 0.05). In summary, exercise training performed by parents reduced visceral offspring adiposity, the diameter of subcutaneous adipocytes and improved metabolic parameters associated to metabolic syndrome.  相似文献   
126.
This study evaluated the effect of a multi-component intervention on motor performance (MP) and metabolic risk markers (MRM) in overweight/obese youth. A secondary aim was to examine whether changes in MP are associated to changes in MRM. A 3-month multi-component intervention was performed, consisting of physical exercise sessions (twice/week;1h), nutritional education sessions (once/month), and parental support (twice/week). The sample included 35 volunteers (7–13 y.o), allocated to intervention (INT, n = 17) and control (CONT, n = 18) group. Variables were measured pre (T0) and post intervention (T1). Fasting blood samples were analyzed for MRM. MP tests included the measurement of health related physical fitness components and motor coordination performance (KTK battery). To assess food intake, a 24-hour recall diary was used. GLM-ANCOVA was performed. Standardized scores were calculated for the outcome variables, and multilinear regressions were applied to analyze associations between the key variables. INT group showed improvements in MP, glycolytic and hepatic profiles. After adjustments for MVPA, SB, total intake and maturational stage, negative associations between %ΔMP and %Δglycolytic (β = -.424; 95%CI:-0.343:-0.022), and %Δhepatic scores (β = -.382 95%CI:-0.001:-0.009) were observed. The intervention produced a moderate-to-high effect on the MP and some MRM. Changes in MP were inversely associated with changes in glycolytic and hepatic markers.  相似文献   
127.
International Journal for Educational and Vocational Guidance - This article proposes a model of antecedents and consequences of student satisfaction in Higher Technical-Vocational Education (HTVE)...  相似文献   
128.
The paper provides an overview of the present position. It attempts to identify the causational factors in situations of child neglect, abuse and violence and to pinpoint areas where there is a lacuna in information and knowledge. The study takes prevalence of abandoned children, failure to meet a child's basic needs and underutilization of services provided free by the state as indices of neglect. Measured in these terms it seems that though in Sri Lanka children are considered a blessing, yet they are also subject to neglect though this is not deliberate on the part of parents but arising from numerous factors, mainly poverty and ignorance. Other influences also operate such as cultural values and weaknesses in the delivery systems. Today females of all socioeconomic levels seek employment, both locally and abroad. This can lead to child neglect since community services for child care are inadequate and traditional help is dwindling. The negative impact on children of certain aspects of modernization is also considered. Abuse of children manifests itself mainly in child domestic labour and the exploitation, particularly of malformed and diseased children, in the trade of begging. Violence as judged by reported cases is minimal. But considering social attitudes regarding physical punishment, its prevalence may be wider than generally believed. The need for statistics and studies on all aspects of child care and child behaviour have come out in the study.  相似文献   
129.
Visualizing anatomical structures and functional processes in three dimensions (3D) are important skills for medical students. However, contemplating 3D structures mentally and interpreting biomedical images can be challenging. This study examines the impact of a new pedagogical approach to teaching neuroanatomy, specifically how building a 3D‐model from oil‐based modeling clay affects learners’ understanding of periventricular structures of the brain among undergraduate medical students in Colombia. Students were provided with an instructional video before building the models of the structures, and thereafter took a computer‐based quiz. They then brought their clay models to class where they answered questions about the structures via interactive response cards. Their knowledge of periventricular structures was assessed with a paper‐based quiz. Afterward, a focus group was conducted and a survey was distributed to understand students’ perceptions of the activity, as well as the impact of the intervention on their understanding of anatomical structures in 3D. Quiz scores of students that constructed the models were significantly higher than those taught the material in a more traditional manner (P < 0.05). Moreover, the modeling activity reduced time spent studying the topic and increased understanding of spatial relationships between structures in the brain. The results demonstrated a significant difference between genders in their self‐perception of their ability to contemplate and rotate structures mentally (P < 0.05). The study demonstrated that the construction of 3D clay models in combination with autonomous learning activities was a valuable and efficient learning tool in the anatomy course, and that additional models could be designed to promote deeper learning of other neuroanatomy topics. Anat Sci Educ 11: 137–145. © 2017 American Association of Anatomists.  相似文献   
130.
The purpose of this study was to develop a teaching quality assessment questionnaire and assess its reliability by using it with a sample of first‐year medical students. Principal components analysis with varimax orthogonal rotation resulted in the development of a 12‐item, two‐component tool, adequate for use in lectures and small‐group sessions. The two components were named ‘curriculum’ and ‘relationship’. The Cronbach coefficient alpha values indicated high reliability and internal consistency. According to the results obtained this teaching quality scale is a reliable measure and may be useful in identifying themes in disciplines and among teachers that may benefit from some professional development. Amongst its advantages is that it can be used with an optical reading tool.  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