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   1464872篇
  免费   105037篇
  国内免费   4561篇
耳鼻咽喉   18512篇
儿科学   47055篇
妇产科学   39600篇
基础医学   216623篇
口腔科学   40540篇
临床医学   137175篇
内科学   286351篇
皮肤病学   29889篇
神经病学   122559篇
特种医学   51322篇
外国民族医学   367篇
外科学   198175篇
综合类   29408篇
现状与发展   1篇
一般理论   483篇
预防医学   129853篇
眼科学   32514篇
药学   109139篇
  6篇
中国医学   3680篇
肿瘤学   81218篇
  2021年   12874篇
  2019年   13857篇
  2018年   20268篇
  2017年   14778篇
  2016年   15746篇
  2015年   17964篇
  2014年   23847篇
  2013年   36662篇
  2012年   52503篇
  2011年   55720篇
  2010年   31363篇
  2009年   27962篇
  2008年   49858篇
  2007年   52765篇
  2006年   52543篇
  2005年   50604篇
  2004年   48015篇
  2003年   45514篇
  2002年   44006篇
  2001年   64166篇
  2000年   66259篇
  1999年   55152篇
  1998年   15089篇
  1997年   13591篇
  1996年   13444篇
  1995年   12753篇
  1994年   11857篇
  1993年   11118篇
  1992年   43116篇
  1991年   42124篇
  1990年   40840篇
  1989年   38573篇
  1988年   35740篇
  1987年   34816篇
  1986年   33253篇
  1985年   31658篇
  1984年   23799篇
  1983年   20235篇
  1982年   12072篇
  1979年   21719篇
  1978年   15423篇
  1977年   12663篇
  1976年   12455篇
  1975年   12786篇
  1974年   15689篇
  1973年   15375篇
  1972年   14244篇
  1971年   13260篇
  1970年   12267篇
  1969年   11251篇
排序方式: 共有10000条查询结果,搜索用时 0 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