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   3337篇
  免费   267篇
  国内免费   23篇
耳鼻咽喉   28篇
儿科学   101篇
妇产科学   87篇
基础医学   525篇
口腔科学   68篇
临床医学   214篇
内科学   816篇
皮肤病学   111篇
神经病学   254篇
特种医学   249篇
外科学   440篇
综合类   56篇
预防医学   246篇
眼科学   36篇
药学   205篇
  1篇
中国医学   2篇
肿瘤学   188篇
  2023年   22篇
  2022年   32篇
  2021年   82篇
  2020年   52篇
  2019年   105篇
  2018年   102篇
  2017年   66篇
  2016年   65篇
  2015年   90篇
  2014年   117篇
  2013年   124篇
  2012年   164篇
  2011年   193篇
  2010年   108篇
  2009年   107篇
  2008年   147篇
  2007年   148篇
  2006年   168篇
  2005年   146篇
  2004年   139篇
  2003年   140篇
  2002年   131篇
  2001年   98篇
  2000年   97篇
  1999年   84篇
  1998年   74篇
  1997年   53篇
  1996年   49篇
  1995年   49篇
  1994年   49篇
  1993年   44篇
  1992年   39篇
  1991年   40篇
  1990年   56篇
  1989年   47篇
  1988年   52篇
  1987年   61篇
  1986年   36篇
  1985年   48篇
  1984年   18篇
  1983年   30篇
  1982年   10篇
  1981年   17篇
  1980年   17篇
  1979年   10篇
  1978年   13篇
  1977年   10篇
  1975年   14篇
  1972年   8篇
  1966年   9篇
排序方式: 共有3627条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
We review the association between surgically resolvable aortic disease and horseshoe kidney with a discussion of diagnostic problems and therapeutic options.Male patient 81 years of age with horseshoe kidney and an abdominal aortic aneurysm that was discovered by chance in an abdominal ultrasound during a check-up for his prostate condition.A retroperitoneal approach was used in order to resect the aneurysm and perform an aorto-aortic bypass with no complications occurring. Two years after the diagnosis, the patient is still asymptomatic from a vascular point of view.The co-presence of horseshoe kidney and aortic disease needing surgical correction is infrequent, but it significantly increases the technical complexity of aortic reconstruction. A literature review is included.  相似文献   
5.
6.
7.
8.
9.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
10.
The authors studied the effects of 4-hydroxyandrostene-3,17-dione (4-OHA) on progesterone (P), 17 beta-estradiol (E2), and 20 alpha-hydroxy-4-pregnen-3-one synthesis and pregnenolone accumulation in cultured human midluteal cells. A dose-dependent inhibition with and without human chorionic gonadotropin (hCG) of E2 and P production was observed. The accumulation of pregnenolone was significantly enhanced three to fourfold by 4-OHA in this culture system, as compared with control value. In addition, a sevenfold increase on pregnenolone accumulation was observed in the presence of 4-OHA plus 10 IU of hCG as compared with control values and 2.2-fold as compared with the 4-OHA treatments. These in vitro findings indicate a direct effect of 4-OHA on luteal steroidogenesis. Nevertheless, the suppressive effect of 4-OHA on P and E2 production is located at different sites of the steroidogenic pathway. In addition, the results demonstrate that hCG in the presence of 4-OHA stimulated pregnenolone accumulation, suggesting that the inhibition of P synthesis is in some steps after the formation of pregnenolone. These data indicate that the actions of 4-OHA on P or E2 formation have different inhibitory mechanisms.  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