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   1470309篇
  免费   113345篇
  国内免费   12661篇
耳鼻咽喉   17852篇
儿科学   45330篇
妇产科学   37851篇
基础医学   216652篇
口腔科学   38296篇
临床医学   146222篇
内科学   276862篇
皮肤病学   27858篇
神经病学   118346篇
特种医学   52914篇
外国民族医学   431篇
外科学   197012篇
综合类   51870篇
现状与发展   30篇
一般理论   471篇
预防医学   124129篇
眼科学   32292篇
药学   114116篇
  126篇
中国医学   10982篇
肿瘤学   86673篇
  2021年   17991篇
  2020年   12092篇
  2019年   16228篇
  2018年   21043篇
  2017年   16703篇
  2016年   17394篇
  2015年   21285篇
  2014年   28320篇
  2013年   39301篇
  2012年   54401篇
  2011年   57628篇
  2010年   34736篇
  2009年   31028篇
  2008年   50022篇
  2007年   52346篇
  2006年   51825篇
  2005年   49616篇
  2004年   46221篇
  2003年   44064篇
  2002年   42194篇
  2001年   63910篇
  2000年   65069篇
  1999年   54595篇
  1998年   16109篇
  1997年   14922篇
  1996年   14273篇
  1995年   13572篇
  1994年   12616篇
  1993年   11591篇
  1992年   42354篇
  1991年   41464篇
  1990年   40091篇
  1989年   37899篇
  1988年   35083篇
  1987年   34123篇
  1986年   32561篇
  1985年   30968篇
  1984年   23316篇
  1983年   19811篇
  1982年   11947篇
  1979年   20951篇
  1978年   14959篇
  1977年   12213篇
  1976年   12011篇
  1975年   12202篇
  1974年   14927篇
  1973年   14573篇
  1972年   13441篇
  1971年   12525篇
  1970年   11574篇
排序方式: 共有10000条查询结果,搜索用时 16 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