全文获取类型
收费全文 | 614篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
教育 | 371篇 |
科学研究 | 205篇 |
各国文化 | 4篇 |
体育 | 8篇 |
文化理论 | 4篇 |
信息传播 | 27篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 14篇 |
2018年 | 30篇 |
2017年 | 32篇 |
2016年 | 25篇 |
2015年 | 21篇 |
2014年 | 21篇 |
2013年 | 64篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 26篇 |
2009年 | 26篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 21篇 |
2001年 | 20篇 |
2000年 | 14篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 18篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1967年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有619条查询结果,搜索用时 15 毫秒
31.
32.
33.
Student perceptions of the information professions and their master's program in information studies
Joan M. Cherry Wendy M. Duff Nalini Singh Luanne Freund 《Library & information science research》2011,33(2):120-131
Library and information (LIS) education is undergoing a major transformation. During this time of change, there is a pressing need for data from all stakeholder groups to support strategic decisions within individual schools and across the discipline as a whole; students are a key stakeholder group. This paper reports on a 4-year study of master's students enrolled in an institution undergoing a transition toward an iSchool. The self-administered questionnaire was distributed to students enrolled in the Master of Information Studies program at the University of Toronto eight times: to incoming students in the fall term for 4 years, and to the entire student body in the spring term of those same years. The data collected from approximately 1000 questionnaires indicate that students arrive excited about the information professions and optimistic about employment opportunities. As they progress through the program, however, many are not satisfied with professional aspects of their program. They want courses that prepare them for their first professional position, and opportunities to gain experience, which they believe will increase their employability. The data from the 4-year period revealed fluctuations over the years, which indicates the value of examining longitudinal data. 相似文献
34.
Gupta S Verma M Gupta AK Kaur A Kaur V Singh K 《Indian journal of clinical biochemistry : IJCB》2011,26(2):178-181
Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines
recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism
and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and
the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples
(87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently
as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests.
77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7%
in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction
and order the appropriate test in a rational and cost effective manner. 相似文献
35.
Singh B Goswami B Gupta VK Chawla R Mallika V 《Indian journal of clinical biochemistry : IJCB》2011,26(2):131-135
Ensuring quality of laboratory services is the need of the hour in the field of health care. Keeping in mind the revolution
ushered by six sigma concept in corporate world, health care sector may reap the benefits of the same. Six sigma provides
a general methodology to describe performance on sigma scale. We aimed to gauge our laboratory performance by sigma metrics.
Internal quality control (QC) data was analyzed retrospectively over a period of 6 months from July 2009 to December 2009.
Laboratory mean, standard deviation and coefficient of variation were calculated for all the parameters. Sigma was calculated
for both the levels of internal QC. Satisfactory sigma values (>6) were elicited for creatinine, triglycerides, SGOT, CPK-Total
and Amylase. Blood urea performed poorly on the sigma scale with sigma <3. The findings of our exercise emphasize the need
for detailed evaluation and adoption of ameliorative measures in order to effectuate six sigma standards for all the analytical
processes. 相似文献
36.
A simple design method for the cosine-modulated filter banks using weighted constrained least square technique 总被引:1,自引:0,他引:1
This paper presents a simple and efficient design method for cosine-modulated filter banks with prescribed stopband attenuation, passband ripple, and channel overlap. The method casts the design problem as a linear minimization of filter coefficients such that their value at ω=π/2M is 0.707, which results in a simpler, more direct design procedure. The weighted constrained least squares technique is exploited for designing the prototype filter for cosine modulation (CM) filter banks. Several design examples are included to show the increased efficiency and flexibility of the proposed method over the exiting methods. An application of the proposed method is considered in the area of sub-band coding of the ECG and speech signals. 相似文献
37.
Surface features such as uneven playing surfaces, low impact absorption capacity and inappropriate friction/traction characteristics are connected with injury prevalence whereas force impact during foot strike has been suggested to be an important mechanism of intravascular haemolysis during running. We aimed to evaluate intravascular haemolysis during running and compare the effect of running on two different types of surfaces on haemolysis. We selected two surfaces (asphalt and grass) on which these athletes usually run. Participants were randomly assigned to group A (asphalt) or group B (grass) with 10 athletes in each group. Each athlete completed one hour of running at the calculated target heart rate (60-70%). Venous blood samples were collected before and immediately after running. We measured unconjugated bilirubin (UBR) (mg · dl(-1)), lactate dehydrogenase (LDH) (μ · ml(-1)), haemoglobin (g · l(-1)) and serum ferritin (ng · ml(-1)) as indicators of haemolysis. Athletes who ran on grass demonstrated an increase in the haematological parameters (UBR: P < 0.01, LDH: P < 0.05) when compared to athletes who ran on asphalt (UBR: P < 0.05, LDH: P = 0.241). Our findings indicate that intravascular haemolysis occurs significantly after prolonged running. Furthermore, we conclude that uneven grass surface results in greater haemolysis compared to asphalt road. 相似文献
38.
Sanjeev Shruthi Molly Mary Thabah Bobby Zachariah Vir Singh Negi 《Indian journal of clinical biochemistry : IJCB》2021,36(2):185
To study oxidative stress in systemic lupus erythematosus (SLE) by estimating serum oxidised LDL (OxLDL), 8-hydroxy-2′-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and total anti-oxidant status and to correlate with SLE disease activity and disease damage. Eighty SLE patients satisfying the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) 2012 criteria and 80 healthy controls were studied. Exclusion criteria were infections, renal insufficiency, other connective tissue diseases, drug-induced lupus, smoking, alcohol consumption. Disease activity was measured by SLE disease activity index-2 K (SLEDAI), disease damage was quantified by SLICC-Damage Index (SDI). Sera was tested for OxLDL, 8-OHdG, and total antioxidant status (TAS) by double-antibody sandwich ELISA; MDA measured by Colorimetric assay. Oxidative stress markers were compared between group1- controls, group 2-mildly active SLE (SLEDAI ≤ 5), group 3- moderate to highly active SLE (SLEDAI ≥ 6). SLE patients had significantly higher MDA, 8-OHdG and lower TAS when compared to healthy controls, while OxLDL was similar in the three groups. MDA, 8-OHdG were significantly higher, TAS lower in group 3 compared to group 2. MDA had positive correlation with SLEDAI, TAS negatively correlated with SLEDAI. SLE with neuropsychiatric manifestations, vasculitis, anti-sdDNA antibodies had higher MDA, MDA/TAS ratio. SLE patients with thrombocytopenia, and vasculitis had higher OxLDL. Only OxLDL was significantly higher in those patients who have SDI > 1. SLE patients have increased oxidative stress measured by increases in MDA, 8-OHdG, and lower total antioxidant status that was associated with disease activity and some disease manifestations. However only OxLDL was associated with damage. 相似文献
39.
Virtual education in universities: a technological imperative 总被引:1,自引:0,他引:1
John O'Donoghue Gurmak Singh & Lisa Dorward 《British journal of educational technology : journal of the Council for Educational Technology》2001,32(5):511-523
Many educational journals have debated the issue of the "virtual university". As technology is improving and evolving, such "virtuality" becomes a reality. The forecasts are that, in the not too distant future, it will be possible for courses to be completed solely by the use of the World Wide Web or Internet. These "virtual classrooms" will take the place of the solid buildings where students currently attend lectures, at set times in set rooms. The information will be gathered at the student's convenience and assignments will be handed in via this medium. There is potentially an advantage for everyone involved, from the reduced building resource costs to the availability of teaching support 24 hours a day, 7 days a week
Whilst many of these studies identify the benefits of technology in education there are dissenting voices from many other quarters. However there are also arguments identifying the disadvantages to the technology based delivery systems proposed. Either way, there are going to be radical changes in the methods which students will use to tackle the workload involved in studying towards a degree. This paper will explore both sides of the argument. The main contention of this paper is that technology undoubtedly will offer many benefits for the learner, however, the pitfalls need careful consideration in the design of the learning environment. This paper uses examples from educational institutions across different cultures. 相似文献
Whilst many of these studies identify the benefits of technology in education there are dissenting voices from many other quarters. However there are also arguments identifying the disadvantages to the technology based delivery systems proposed. Either way, there are going to be radical changes in the methods which students will use to tackle the workload involved in studying towards a degree. This paper will explore both sides of the argument. The main contention of this paper is that technology undoubtedly will offer many benefits for the learner, however, the pitfalls need careful consideration in the design of the learning environment. This paper uses examples from educational institutions across different cultures. 相似文献
40.