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   21560篇
  免费   1365篇
  国内免费   57篇
耳鼻咽喉   354篇
儿科学   1162篇
妇产科学   526篇
基础医学   1893篇
口腔科学   396篇
临床医学   1636篇
内科学   5099篇
皮肤病学   346篇
神经病学   1203篇
特种医学   756篇
外科学   3900篇
综合类   458篇
一般理论   4篇
预防医学   1137篇
眼科学   890篇
药学   1697篇
中国医学   74篇
肿瘤学   1451篇
  2023年   158篇
  2022年   112篇
  2021年   712篇
  2020年   442篇
  2019年   654篇
  2018年   773篇
  2017年   546篇
  2016年   566篇
  2015年   557篇
  2014年   888篇
  2013年   1095篇
  2012年   1654篇
  2011年   1519篇
  2010年   939篇
  2009年   726篇
  2008年   1113篇
  2007年   1109篇
  2006年   1035篇
  2005年   959篇
  2004年   858篇
  2003年   719篇
  2002年   628篇
  2001年   480篇
  2000年   510篇
  1999年   399篇
  1998年   150篇
  1997年   126篇
  1996年   97篇
  1995年   118篇
  1994年   105篇
  1993年   84篇
  1992年   280篇
  1991年   253篇
  1990年   220篇
  1989年   212篇
  1988年   172篇
  1987年   176篇
  1986年   155篇
  1985年   168篇
  1984年   147篇
  1983年   141篇
  1982年   65篇
  1981年   74篇
  1979年   116篇
  1978年   86篇
  1977年   64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 0 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