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   3450373篇
  免费   258308篇
  国内免费   9225篇
耳鼻咽喉   46789篇
儿科学   113837篇
妇产科学   96371篇
基础医学   485196篇
口腔科学   95327篇
临床医学   318358篇
内科学   677497篇
皮肤病学   81659篇
神经病学   284305篇
特种医学   131507篇
外国民族医学   1112篇
外科学   515409篇
综合类   74627篇
现状与发展   7篇
一般理论   1356篇
预防医学   270229篇
眼科学   78126篇
药学   250165篇
  8篇
中国医学   7277篇
肿瘤学   188744篇
  2019年   27832篇
  2018年   38936篇
  2017年   29859篇
  2016年   34322篇
  2015年   38630篇
  2014年   53842篇
  2013年   80874篇
  2012年   107866篇
  2011年   114419篇
  2010年   68536篇
  2009年   65380篇
  2008年   106307篇
  2007年   112801篇
  2006年   114572篇
  2005年   110349篇
  2004年   105789篇
  2003年   102014篇
  2002年   98642篇
  2001年   165964篇
  2000年   170049篇
  1999年   143042篇
  1998年   41547篇
  1997年   36968篇
  1996年   36923篇
  1995年   35722篇
  1994年   32641篇
  1993年   30529篇
  1992年   110446篇
  1991年   106005篇
  1990年   102706篇
  1989年   99004篇
  1988年   90803篇
  1987年   89005篇
  1986年   83344篇
  1985年   79821篇
  1984年   59853篇
  1983年   50774篇
  1982年   30387篇
  1981年   27075篇
  1979年   52908篇
  1978年   37472篇
  1977年   31565篇
  1976年   29434篇
  1975年   30986篇
  1974年   36916篇
  1973年   35260篇
  1972年   33153篇
  1971年   30677篇
  1970年   28497篇
  1969年   27141篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.  相似文献   
63.
64.
65.
66.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
67.
68.

Purpose

Endovascular treatment with mechanical thrombectomy devices demonstrated high recanalization rates but functional outcome did not correlate with high rates of recanalization obtained. Patient selection prior to the endovascular treatment is very important in the final outcome of the patient. The primary aim of our study was to evaluate the prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) and Pons-Midbrain Index (PMI) scores in patients with Basilar Artery Occlusion (BAO) treated with successful angiographic recanalization after mechanical thrombectomy.

Methods

Retrospective single-center study including 18 patients between 2008 and 2013 who had acute basilar artery occlusion managed with endovascular treatment within 24 hours from symptoms onset and with successful angiographic recanalization. The patients were initially classified into two groups according to clinical outcome and mortality at 90 days. For analysis we also divided patients into groups based on pc-ASPECTS (≥8vs.< 8) and PMI (≥3vs.< 3) on non-contrast CT (NCCT) and CT Angiography Source Images (CTASI). Imaging data were correlated to clinical outcome and mortality rate.

Results

CTASI pc-ASPECTS, dichotomized at < 8 versus≥8, was associated with a favorable outcome (RR: 2.6; 95% CI: 1.3-5.2) and a reduced risk of death (RR: 6.5: 95% CI: 7.8-23.3). All patients that survived and were functionally independent had pc-ASPECTS score≥8. None of the 5 patients with CTASI pc-ASPECTS score less than 8 survived.

Conclusion

PC-ASPECTS on CTASI is helpful for predicting functional outcome after BAO recanalization with endovascular treatment. These results should be validated in a randomized controlled trial in order to decide whether or not to treat a patient with BAO.  相似文献   
69.
70.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  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