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   1177篇
  免费   114篇
  国内免费   40篇
耳鼻咽喉   9篇
儿科学   23篇
妇产科学   20篇
基础医学   144篇
口腔科学   20篇
临床医学   209篇
内科学   275篇
皮肤病学   13篇
神经病学   42篇
特种医学   127篇
外科学   119篇
综合类   25篇
预防医学   95篇
眼科学   13篇
药学   132篇
中国医学   10篇
肿瘤学   55篇
  2021年   15篇
  2020年   9篇
  2019年   19篇
  2018年   23篇
  2017年   14篇
  2016年   12篇
  2015年   22篇
  2014年   24篇
  2013年   44篇
  2012年   33篇
  2011年   34篇
  2010年   45篇
  2009年   35篇
  2008年   36篇
  2007年   59篇
  2006年   43篇
  2005年   36篇
  2004年   19篇
  2003年   24篇
  2002年   24篇
  2001年   22篇
  2000年   27篇
  1999年   25篇
  1998年   31篇
  1997年   28篇
  1996年   21篇
  1995年   20篇
  1994年   23篇
  1993年   21篇
  1992年   34篇
  1991年   29篇
  1990年   25篇
  1989年   31篇
  1988年   37篇
  1987年   23篇
  1986年   29篇
  1985年   34篇
  1984年   24篇
  1983年   31篇
  1982年   17篇
  1981年   13篇
  1980年   16篇
  1979年   22篇
  1978年   12篇
  1977年   12篇
  1976年   16篇
  1974年   9篇
  1972年   9篇
  1971年   12篇
  1840年   13篇
排序方式: 共有1331条查询结果,搜索用时 156 毫秒
1.
2.
Recently, public and private efforts have been mounted to promote screening mammography. To assess recent trends in the percentage of women 50 years of age and older who have had a screening mammogram, we analyzed data from interviews from women from 33 states who participated in the 1987 Behavioral Risk Factor Surveillance System. Our study group included 8,402 women 50 years of age and older who had visited a physician for a routine checkup in the last year; among these 8,402 women, only 29% reported having had a screening mammogram in the past year. However, of the women in the study group, the percentage who had a screening mammogram in the last year showed a relative increase of 38% during 1987, from 24% for women interviewed in the first quarter of 1987 to 33% for women interviewed in the fourth quarter. However, not all groups of patients benefited equally from the observed trend--the absolute and relative increases in the percentage of women screened were lowest for women who were older, less educated, in low-income groups, and who had poor personal health practices. Although the percentage of women 50 years of age and older who reported being screened increased dramatically during 1987, special efforts are needed to reach the patient groups that are being left behind in the trend toward increased use of screening mammograms.  相似文献   
3.
BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most prevalent fatal cancers in the world. Despite advances in early diagnosis and improvements in surgical techniques, the survival of patients with HCC even after resection is poor because of the high incidence of recurrences. Therefore, the identification of prognostic factors may be helpful in the development of new treatment protocols. AIMS: To investigate HER-2/neu status in HCC by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH), and to explore the possibility of using trastuzumab in the treatment of HCC. METH ODS: Eight hundred and sixty eight surgical samples from patients with primary HCC were examined for their HER-2/neu status. IHC for HER-2/neu was performed with the HercepTest kit; FISH analysis was performed with the PathVysion HER-2 DNA probe kit. The correlations between HER-2/neu overexpression and clinicopathological characteristics were analysed statistically. RESULTS: HER-2/neu overexpression was detected in 21 (2.42%) of the 868 primary HCCs. Only one specimen showed HER-2/neu gene amplification by FISH. No significant associations were found between HER-2/neu overexpression and the clinicopathological parameters. CONCLUSIONS: There is a low frequency of HER-2/neu overexpression/amplification in HCC. There appears to be no role for HER-2/neu as a prognostic marker and no benefit of anti-HER-2/neu trastuzumab treatment in patients with HCC.  相似文献   
4.
5.
Transforming growth factors-beta (TFG beta s) are multifunctional peptides that affect proliferation, differentiation, and many other functions in a variety of cell types. In this study we examined the effect of TGF beta 1 on aldosterone and adrenal renin production using cultured bovine adrenal zona glomerulosa cells. Collagenase-dispersed zona glomerulosa cells were incubated in PFMR-4 medium containing 10% fetal calf serum for 72 h, and the medium was replaced with serum-free medium for the next 24 h. The cells during this 24-h period were exposed to TGF beta 1, ACTH, and (Bu)2cAMP (dbcAMP). It was observed that TGF beta 1 at 1 nM 1) inhibited basal aldosterone secretion from 680.0 +/- 40.0 to 270.0 +/- 10.0 pg/10(6) cells.h, 2) inhibited ACTH- and dbcAMP-stimulated aldosterone production, 3) increased levels of active renin in the cells from 17.8 +/- 2.5 to 70.7 +/- 4.4 pg angiotensin-I/10(6) cells.h and prorenin from 270.0 +/- 5.0 to 970.0 +/- 90 pg angiotensin-I/10(6) cells.h, 4) stimulated prorenin in the medium synergistically in combination with ACTH and dbcAMP, and 5) had no significant effect on basal cAMP production, but significantly inhibited the ACTH-stimulated production of cAMP. These observations show that TGF beta 1 is a potent inhibitor of basal and ACTH- and cAMP-stimulated aldosterone production and inhibits ACTH-stimulated cAMP production. Contrary to its effect on aldosterone, TGF beta 1 stimulates the synthesis and release of adrenal renin and prorenin. TGF beta 1 may act as an autocrine or paracrine regulator of aldosterone production.  相似文献   
6.
7.
A deceased donor (DD) allocation system incorporating net life survival benefit has been proposed. In this system, many kidneys will be shifted to younger recipients, thereby decreasing their waiting times. The goal of this study was to determine the potential effects of altering waiting times on the likelihood of live donor kidney transplantation (LDKT). We analyzed 93,727 waiting list candidates to determine the association of various patient factors with likelihood of LDKT. The proportion of patients receiving LDKT was compared by the median DD waiting time at that patient's transplant center for someone of that patient's age category and race. LDKT was consistently higher as waiting times became longer. After adjusting for all other factors associated with likelihood of LDKT, waiting time remained a significant, independent predictor. Patients with the longest DD waiting times had 2.3-fold higher odds of LDKT (95% CI 2.11-2.58, p < 0.001). In planning the new DD allocation policy, we must account for resulting alterations in LDKT. It is possible that shifting DD kidneys to younger recipients may decrease LDKT or shift it to older recipients, net effects not consistent with the goal of net life survival benefit.  相似文献   
8.
中西医结合医院单病种的质量管理及其作用   总被引:1,自引:0,他引:1  
针对中西医结合医院单病种质量评定没有现成的、规范的标准的现状,就中西医结合单病种的质量管理方法及其在中西医结合医院建设中的作用进行了论述。  相似文献   
9.
10.
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