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   1462621篇
  免费   105121篇
  国内免费   4587篇
耳鼻咽喉   18464篇
儿科学   47049篇
妇产科学   39365篇
基础医学   216351篇
口腔科学   40421篇
临床医学   137284篇
内科学   285624篇
皮肤病学   29815篇
神经病学   122281篇
特种医学   51295篇
外国民族医学   367篇
外科学   198123篇
综合类   29465篇
现状与发展   1篇
一般理论   482篇
预防医学   129586篇
眼科学   32522篇
药学   108997篇
  6篇
中国医学   3683篇
肿瘤学   81148篇
  2021年   12926篇
  2019年   13895篇
  2018年   20235篇
  2017年   14782篇
  2016年   15734篇
  2015年   17977篇
  2014年   23873篇
  2013年   36668篇
  2012年   52339篇
  2011年   55428篇
  2010年   31307篇
  2009年   28013篇
  2008年   49675篇
  2007年   52558篇
  2006年   52303篇
  2005年   50348篇
  2004年   47765篇
  2003年   45258篇
  2002年   43760篇
  2001年   64031篇
  2000年   66034篇
  1999年   55006篇
  1998年   15098篇
  1997年   13599篇
  1996年   13446篇
  1995年   12749篇
  1994年   11864篇
  1993年   11132篇
  1992年   43149篇
  1991年   42135篇
  1990年   40869篇
  1989年   38597篇
  1988年   35764篇
  1987年   34839篇
  1986年   33279篇
  1985年   31671篇
  1984年   23799篇
  1983年   20243篇
  1982年   12080篇
  1979年   21735篇
  1978年   15430篇
  1977年   12665篇
  1976年   12462篇
  1975年   12793篇
  1974年   15697篇
  1973年   15377篇
  1972年   14246篇
  1971年   13262篇
  1970年   12270篇
  1969年   11254篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
45.
46.
47.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
48.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  相似文献   
49.
50.
Pre-eclamptic toxaemia (PET) may be associated with both endothelial dysfunction (ED) and sleep-disordered breathing (SDB). It was hypothesised that females with PET would demonstrate both SDB and ED, and that a correlation between these two would suggest a potential causative association. A total of 17 females with PET and 25 matched females with uncomplicated pregnancy were studied. They underwent a nocturnal ambulatory sleep study (using Watch_PAT100) and noninvasive evaluation of endothelial function utilising the reactive hyperaemia test (using Endo_PAT 2000). A higher ratio of post- to pre-occlusion pulse-wave amplitude (endothelial function index (EFI)) indicated better endothelial function. Females with PET had a significantly higher respiratory disturbance index (RDI) and lower EFI than controls (18.4+/-8.4 versus 8.3+/-1.3.h(-1), and 1.5+/-0.1 versus 1.8+/-0.1, respectively). Blood pressure significantly correlated with RDI and with EFI. EFI tended to correlate with RDI. In conclusion, these results suggest that both sleep-disordered breathing and endothelial dysfunction are more likely to occur in females with pre-eclamptic toxaemia than in females with uncomplicated pregnancies. The current authors speculate that respiratory disturbances contribute to the functional abnormality of the blood vessels seen in females with pre-eclamptic toxaemia, although causality cannot be determined based on this study.  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