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   1375篇
  免费   199篇
  国内免费   18篇
耳鼻咽喉   21篇
儿科学   51篇
妇产科学   35篇
基础医学   99篇
口腔科学   39篇
临床医学   224篇
内科学   290篇
皮肤病学   104篇
神经病学   60篇
特种医学   136篇
外科学   196篇
综合类   95篇
现状与发展   30篇
预防医学   62篇
眼科学   16篇
药学   44篇
中国医学   3篇
肿瘤学   87篇
  2024年   18篇
  2023年   182篇
  2022年   12篇
  2021年   18篇
  2020年   57篇
  2019年   21篇
  2018年   54篇
  2017年   49篇
  2016年   40篇
  2015年   56篇
  2014年   88篇
  2013年   70篇
  2012年   33篇
  2011年   34篇
  2010年   77篇
  2009年   89篇
  2008年   34篇
  2007年   60篇
  2006年   30篇
  2005年   18篇
  2004年   14篇
  2003年   16篇
  2002年   17篇
  2001年   14篇
  2000年   16篇
  1999年   26篇
  1998年   36篇
  1997年   49篇
  1996年   40篇
  1995年   36篇
  1994年   31篇
  1993年   37篇
  1992年   12篇
  1991年   19篇
  1990年   15篇
  1989年   30篇
  1988年   26篇
  1987年   21篇
  1986年   6篇
  1985年   12篇
  1984年   4篇
  1983年   5篇
  1982年   9篇
  1981年   10篇
  1980年   12篇
  1978年   5篇
  1977年   3篇
  1976年   13篇
  1975年   10篇
  1974年   3篇
排序方式: 共有1592条查询结果,搜索用时 15 毫秒
91.
Background: Impaired intestinal mucosal barrier (IMB) function is common in traumatic brain injury (TBI), but dopamine receptors (DRs) change in intestinal mucosa after TBI, and effects of enteral nutrition (EN) and supplements on IMB function remain unclear. Our purpose was to study the effects of EN and supplements on intestinal mucosal permeability (IMPB) and the expression of DRs DRD1 and DRD2 in the intestinal mucosa of rats with TBI. Methods: Forty‐eight rats were divided into 8 groups; control, animals with TBI, dopamine group, animals with TBI treated with dopamine antagonist, EN alone, or EN combined with glutamine, probiotics, or a combination of probiotics and glutamine daily after TBI. Results: The IMPB was improved in the glutamine, probiotics, and combination groups. Including probiotics improved IMPB more than adding glutamine, and bacterial translocation in the intestines after TBI was reduced in the probiotics and combination groups (all Ps < .01). TBI led to elevated DRD1 and DRD2 mRNA and protein levels, which were reduced in the DA antagonist, glutamine, probiotics, and combination groups. DRD2 mRNA and protein levels in the probiotics and combination groups were decreased more than in the DA antagonist group (all Ps < .01). The increased IMPB after TBI correlated with increased DRD1 and DRD2 levels in the rat intestinal mucosa. Conclusion: EN supplemented with probiotics or combining glutamine and probiotics lowers the increased IMPB, bacterial translocation, and DRD1 and DRD2 mRNA and protein expression in rat intestinal mucosa caused by TBI.  相似文献   
92.

Background  

Diabetes prevalence is increasing. The Finnish Diabetes Prevention Study (DPS) showed a 58% reduction in Type 2 Diabetes (T2D) incidence in adults with impaired glucose tolerance (IGT). The European Diabetes Prevention Study (EDIPS) extends the DPS to different European populations, using the same study design. In the Newcastle arm of this study (EDIPS-Newcastle), we tested the hypothesis that T2D can be prevented by lifestyle intervention and explored secondary outcomes in relation to diabetes incidence.  相似文献   
93.
94.

Background  

Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD) on process, intermediate and final outcomes of care in a general practice setting.  相似文献   
95.

Background

Immunological response of host and parasite play a key role in developing vaccination and immunization. The present study deals with the immune response and effecter mechanism, which was confirmed by migration inhibition factor (MIF).

Methods

The present work was conducted in Parasitological Lab of Postgraduate Department of Zoology, Government Holkar Science College, Indore (M.P.) during 2006–2007. For MIF assay, lymphocytes were separated from heparinized blood of experimental and control mice. Aliquots of cell suspension were placed in four wells cut in a preparation of agarose in a Petri dish. Two wells were filled with soluble test antigen, while rest two wells were filled with medium (control wells). Petri dish was incubated overnight at 37 °C in a humidified environment at 5% CO2 in air. Cells migrated under the agarose in a circle were fixed and stained. Diameters of the migration areas were measured with ocular micrometer.

Results

MIF reaction was maximum (44.2%) in the group IVEgESAg5 and minimum (10.8%) in the group IVASoAg1. The maximum MIF reaction was shown by eggs ES antigen and least by adult worm somatic antigen. The interesting observation was that migration inhibition increases as dose increased or we could say the reaction was dose dependent.

Conclusion

Increased value of MIF response in vaccinated mice suggested the involvement of lymphocytes in cell-mediated immunity. This study also proves that excretory-secretory (ES) antigen of eggs from Trichuris muris was more effective in imparting immunity in mice.  相似文献   
96.

Background

Neospora caninum, an obligate intracellular protozoan parasite, is recognized as a major cause of abortion in cattle, while limited information is presently available on the seroprevalence of Neospora antibodies in horses’ worldwide. The aim of the present study was to determine serologic prevalence of Neospora infection in horses in Iran.

Methods

Sera from 150 horses from Mashhad suburb in Razavi Khorasan Province, northeast Iran were examined for antibodies to Neospora spp. using Neospora modified direct agglutination test (N-MAT).

Results

Antibodies to this parasite were detected in 45 (30%) of the examined serum samples. Thirty four percent of the samples had titer of 1:40 while then reduced to 30% when 1:80 serum dilution was applied as significant cut off titer.

Conclusion

This study is the first investigation carried out on the Neospora in horses in Iran and indicates that horses in Iran are exposed to this parasite.  相似文献   
97.

Background  

Accurate measurement of physical activity is a pre-requisite for monitoring population health and for evaluating effective interventions. The International Physical Activity Questionnaire (IPAQ) is used as a comparable and standardised self-report measure of habitual physical activity of populations from different countries and socio-cultural contexts. The IPAQ has been modified to produce a New Zealand physical activity questionnaire (NZPAQ). The aim of this study was to validate the IPAQ and NZPAQ against doubly labelled water (DLW). Method: Total energy expenditure (TEE) was measured over a 15-day period using DLW. Activity-related energy expenditure (AEE) was estimated by subtracting the energy expenditure from resting metabolic rate and thermic effect of feeding from TEE. The IPAQ (long form) and NZPAQ (short form) were completed at the end of each 7-day period. Activity-related energy expenditure (IPAQAEE and NZPAQAEE) was calculated from each questionnaire and compared to DLWAEE.  相似文献   
98.
The action of a water soluble benzodiazepine, chlordiazepoxide (CDZ) on the stimulatory effect of adenosine on glucagon secretion from the isolated pancreas of the rat perfused in presence of 2.8 mM glucose was studied. CDZ 10(-7) and 10(-6) M had no effect per se on glucagon secretion under our experimental conditions. In contrast, CDZ 10(-6) M (but not 10(-7) M) markedly reduced the peak of glucagon secretion provoked by adenosine, 2-chloroadenosine (1.65 C 10(-6) M) and by a stable analogue, 5'-N-ethylcarboxamidoadenosine or NECA (1.65 X 10(-8) M). This peripheral interaction between CDZ and adenosine seemed to be specific, since CDZ did not modify the peak of glucagon secretion induced by (-)isoproterenol (10(-8) M). Our results demonstrate an inhibitory effect of CDZ on adenosine-stimulated glucagon secretion.  相似文献   
99.
Serial pulmonary imaging has proved to be effective in the evaluation of patients undergoing total joint arthroplasty. A clinical dilemma arises in asymptomatic patients whose postoperative pulmonary images differ from the preoperative images. The authors prospectively evaluated 403 patients with serial imaging to determine the significance of changed postoperative images in asymptomatic patients undergoing total hip or knee arthroplasty. Twenty-two (5.5%) patients had significant changes on postoperative images. Seventeen were asymptomatic; all but one underwent pulmonary angiography. Documented pulmonary emboli were demonstrated in 100% of patients whose postoperative images changed to indicate a high probability of pulmonary embolism, 71% whose images changed to a moderate probability, and 0% whose images changed to indeterminate probability. Overall, pulmonary emboli occurred in 76% of all asymptomatic patients with significantly change postoperative images. Asymptomatic pulmonary embolism is a significant occurrence after total hip or knee repair, and a changed lung scan with appropriate clinical evaluation is an accurate indicator of pulmonary emboli in asymptomatic postarthroplasty patients.  相似文献   
100.
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