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   4792篇
  免费   238篇
  国内免费   18篇
耳鼻咽喉   14篇
儿科学   53篇
妇产科学   65篇
基础医学   514篇
口腔科学   84篇
临床医学   584篇
内科学   1459篇
皮肤病学   53篇
神经病学   576篇
特种医学   90篇
外科学   421篇
综合类   13篇
预防医学   453篇
眼科学   33篇
药学   357篇
中国医学   3篇
肿瘤学   276篇
  2024年   5篇
  2023年   21篇
  2022年   60篇
  2021年   179篇
  2020年   92篇
  2019年   157篇
  2018年   199篇
  2017年   117篇
  2016年   118篇
  2015年   126篇
  2014年   217篇
  2013年   261篇
  2012年   416篇
  2011年   431篇
  2010年   262篇
  2009年   212篇
  2008年   323篇
  2007年   304篇
  2006年   312篇
  2005年   284篇
  2004年   258篇
  2003年   225篇
  2002年   201篇
  2001年   24篇
  2000年   15篇
  1999年   28篇
  1998年   38篇
  1997年   32篇
  1996年   22篇
  1995年   27篇
  1994年   18篇
  1993年   7篇
  1992年   4篇
  1991年   8篇
  1990年   8篇
  1989年   5篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   4篇
  1981年   4篇
  1980年   1篇
  1979年   1篇
  1971年   1篇
  1964年   1篇
  1962年   2篇
  1961年   1篇
  1960年   3篇
  1933年   1篇
  1929年   1篇
排序方式: 共有5048条查询结果,搜索用时 15 毫秒
991.
992.
993.
Mosquitoes are the main vectors of pathogens affecting wild animals, livestock and humans. Here, we used molecular tools to assess the local circulation of filarial parasites in mosquitoes collected during 2013 from natural, rural and urban habitats from southern Spain. We screened parasites in 22,791 female mosquitoes of the genera Aedes, Culex and Culiseta. Filarial worms were only detected in two mosquito pools. An Ae. caspius pool was positive for Setaria equina and an unidentified worm related to Onchocerca was detected in a Cx. pipiens pool. None of the mosquito pools were positive for Dirofilaria. These results underlay the role of Ae. caspius in the transmission of Setaria parasites among livestock and/or wildlife to humans in southern Spain.  相似文献   
994.

Background

Perceived social support has been found to be associated with depression, subjective well-being and psychological health in cross-sectional studies in people with physical disabilities. No longitudinal studies have been conducted to examine these associations over time using a comprehensive measure of social support.

Objective/hypothesis

We hypothesized that: (1) the amount of perceived social support would be similar across individuals with different diagnoses often associated with disability (i.e., multiple sclerosis [MS], spinal cord injury [SCI], muscular dystrophy [MD]) but (2) lower among men, relative to women, and (3) changes over time in perceived social support would be negatively associated with changes in depressive symptoms across diagnostic groups.

Methods

A survey-based six-year longitudinal study. Depressive symptoms were measured with the PROMIS Depression scale. General (Total Scale), Friend, Family and Significant Other social support were measured with the Multi-dimensional Scale of Perceived Social Support (MSPSS).

Results

The findings indicated no significant differences in any of the perceived social support scales as a function of diagnosis or sex. However, over the course of six years, those reporting increases in social support reported decreases in depressive symptoms, while those reporting decreases in social support reported increases in depressive symptoms.

Conclusions

Changes in perceived social support are inversely related with the changes in depressive symptoms in adults with MS, SCI, and MD. Social support would be a reasonable treatment target in interventions seeking to improve psychological wellbeing in individuals with conditions that are often associated with disabilities.  相似文献   
995.
996.
997.

Background

Periprosthetic joint infection (PJI) remains a major clinical challenge. In this study, we evaluated the diagnostic performance of lipocalin-2 (LCN2), a well-characterized neutrophil protein, in synovial fluid to discriminate PJI and aseptic implant failure.

Methods

Synovial fluid from patients with acute or chronic PJI, aseptic failure, or controls was obtained during surgery. LCN2 was quantified using a modified enzyme immunoassay coupled with chemiluminescence (Architect Urine NGAL; Abbott Laboratories).

Results

Synovial fluid was collected from 72 patients: 22 (30.6%) proven infections, 22 (30.6%) aseptic implant failures, and 28 (38.8%) controls. Synovial fluid was obtained from the hip in 18 (25%) and knee in 54 (75%) cases. Among infections, there were 16 (22.2%) acute and 6 (8.3%) chronic PJIs. The median (interquartile range) LCN2 concentration in synovial fluid was 1536.5 ng/mL (261.8-12,923) in the infection group, 87.0 (54.8-135) in the aseptic group, and 55 (45-67.8) in the control group (P < .001). LCN2 discriminated nearly perfectly between controls and confirmed infection (area under the receiver operating characteristic 0.98, 95% confidence interval 0.95-1.00). The optimal cut-off value for maximal sensitivity (86.3%) and specificity (77.2%) to discriminate aseptic failure versus proven infection was 152 ng/mL, with an area under the receiver operating characteristic of 0.92 (95% confidence interval 0.84-0.99).

Conclusion

LCN2 is a potential novel biomarker that may be helpful to inform surgical teams on the potential risk of PJI and optimize specific surgical interventions as it distinguishes between septic and aseptic failure of prosthesis with high sensitivity and specificity.  相似文献   
998.
999.
1000.
A retrospective angiographic study was done on 19 patients with solitary leiomyomas of the small bowel, one patient with multiple leiomyomas, and two patients with leiomyosarcomas. All patients had gastrointestinal bleeding but no small bowel obstruction. Selective mesenteric angiography was the main diagnostic procedure. Tumoral hypervascularity and dense capillary staining within a well-circumscribed mass were present in all patients. Prominent and irregular feeding arteries were seen in 19 cases and prominent draining veins in 20. Contrast extravasation indicating the site of active bleeding was shown in two patients.  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