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   20121篇
  免费   1284篇
  国内免费   158篇
耳鼻咽喉   330篇
儿科学   1105篇
妇产科学   494篇
基础医学   1756篇
口腔科学   352篇
临床医学   1599篇
内科学   4815篇
皮肤病学   334篇
神经病学   1005篇
特种医学   746篇
外科学   3656篇
综合类   467篇
一般理论   3篇
预防医学   1059篇
眼科学   850篇
药学   1597篇
中国医学   67篇
肿瘤学   1328篇
  2023年   145篇
  2022年   104篇
  2021年   655篇
  2020年   404篇
  2019年   604篇
  2018年   706篇
  2017年   489篇
  2016年   497篇
  2015年   505篇
  2014年   784篇
  2013年   997篇
  2012年   1488篇
  2011年   1348篇
  2010年   849篇
  2009年   671篇
  2008年   1000篇
  2007年   1079篇
  2006年   947篇
  2005年   899篇
  2004年   788篇
  2003年   674篇
  2002年   603篇
  2001年   488篇
  2000年   514篇
  1999年   404篇
  1998年   157篇
  1997年   146篇
  1996年   107篇
  1995年   122篇
  1994年   110篇
  1993年   89篇
  1992年   285篇
  1991年   254篇
  1990年   224篇
  1989年   224篇
  1988年   178篇
  1987年   180篇
  1986年   155篇
  1985年   172篇
  1984年   149篇
  1983年   142篇
  1982年   65篇
  1981年   74篇
  1979年   116篇
  1978年   86篇
  1977年   63篇
  1974年   75篇
  1973年   110篇
  1972年   100篇
  1971年   68篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
PurposeThe clinical manifestations of rickettsial diseases mimic other endemic infections with similar presentations thus posing a serious challenge to clinicians for their diagnosis. For the diagnosis of rickettsial disease serological tests like Weil Felix, ELISA and IFA are used. There are limited studies that have evaluated different serological tests for the diagnosis of rickettsial diseases. Therefore, the present study was undertaken to evaluate the ELISA and Weil Felix test for the diagnosis of rickettsial diseases prevalent in this region.MethodsSamples from 281 patients clinically suspected of rickettsial diseases were tested for spotted fever group (SFG), typhus group (TG) and scrub typhus group (STG) by Weil Felix, ELISA and IFA was taken as the gold standard. Baseline titers and cut-off ODs were calculated by taking samples from healthy blood donors.ResultsThe sensitivity, specificity, positive and negative predictive value of Weil Felix test ranged from 30% to 44%, 83.46%–97.86%, 9%–77%, 92–96% respectively. The sensitivity and specificity, positive and negative predictive value of ELISA ranged from 80.77% to 96.15%, 96.33%–98.43%, 70.21%–88.64%, 92.89%–99.60% respectively. Maximum cross-reactions were observed between SFG and STG by the Weil Felix test and between STG and TG by ELISA.ConclusionsELISA was found to be sensitive and specific for the diagnosis of rickettsial diseases. It is easy to perform, does not require a technical expert for result interpretation and a large number of samples can be processed at a time.  相似文献   
3.
Bergman  David  Modh  Ankit  Schultz  Lonni  Snyder  James  Mikkelsen  Tom  Shah  Mira  Ryu  Samuel  Siddiqui  M. Salim  Walbert  Tobias 《Journal of neuro-oncology》2020,148(2):353-361
Journal of Neuro-Oncology - Outcomes for patients with recurrent high-grade glioma (HGG) progressing on bevacizumab (BEV) are dismal. Fractionated stereotactic radiosurgery (FSRS) has been shown to...  相似文献   
4.

Objective

To determine the association between provider training level and postplacental intrauterine device (IUD) outcomes following insertion instruction by email only.

Study design

We conducted a single-center chart review of demographics, insertion and clinical outcomes within 6 months of delivery for 116 patients who underwent postplacental levonorgestrel 52?mg IUD placement from October 1, 2016, to March 31, 2017.

Results

We confirmed IUD retention, removal or expulsion in 87 of 116 (75.0%) patients by 6 months after delivery. Complete expulsion or removal for malposition occurred in 20 (23.0%) patients and more frequently after vaginal than cesarean delivery (30.2% vs. 4.2%, OR 9.93 [95% CI 1.25–78.96]) and when a postgraduate year (PGY) 1 physician placed the IUD compared to a PGY 2–4 or attending physician (37.5% vs. 14.5%, OR 3.52 [95% CI 1.25–9.94]).

Conclusion

Postplacental levonorgestrel 52?mg IUD expulsion rates are associated with provider training level as well as delivery route, though the individual association of each of these factors is difficult to ascertain given the high degree of collinearity between these two variables in our study.  相似文献   
5.
6.
7.
8.
9.
The SARS-CoV-2 virus, or COVID-19, is responsible for the current global pandemic and has resulted in the death of over 400,000 in the United States. Rates of venous thromboembolism have been noted to be much higher in those infected with COVID-19. Here we report a case-series of COVID-19 patients with diverse presentations of pulmonary embolism (PE). We also briefly describe the pathophysiology and mechanisms for pulmonary embolism in COVID-19. These cases indicate a need to maintain a high index of suspicion for PE in patients with COVID-19, as well as the need to consider occult COVID-19 infection in patients with PE in the right clinical circumstance.  相似文献   
10.
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