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   3110篇
  免费   456篇
  国内免费   18篇
耳鼻咽喉   35篇
儿科学   111篇
妇产科学   54篇
基础医学   375篇
口腔科学   49篇
临床医学   421篇
内科学   665篇
皮肤病学   152篇
神经病学   148篇
特种医学   196篇
外科学   411篇
综合类   168篇
现状与发展   30篇
一般理论   2篇
预防医学   305篇
眼科学   30篇
药学   224篇
中国医学   5篇
肿瘤学   203篇
  2023年   190篇
  2022年   23篇
  2021年   54篇
  2020年   80篇
  2019年   50篇
  2018年   81篇
  2017年   64篇
  2016年   58篇
  2015年   74篇
  2014年   123篇
  2013年   117篇
  2012年   107篇
  2011年   119篇
  2010年   110篇
  2009年   117篇
  2008年   122篇
  2007年   140篇
  2006年   112篇
  2005年   102篇
  2004年   98篇
  2003年   85篇
  2002年   85篇
  2001年   67篇
  2000年   79篇
  1999年   83篇
  1998年   56篇
  1997年   73篇
  1996年   75篇
  1995年   53篇
  1994年   50篇
  1993年   54篇
  1992年   49篇
  1991年   43篇
  1990年   46篇
  1989年   75篇
  1988年   58篇
  1987年   51篇
  1986年   40篇
  1985年   39篇
  1984年   27篇
  1983年   28篇
  1982年   26篇
  1980年   24篇
  1979年   25篇
  1978年   23篇
  1976年   25篇
  1975年   26篇
  1974年   24篇
  1972年   35篇
  1968年   22篇
排序方式: 共有3584条查询结果,搜索用时 828 毫秒
1.
2.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
3.
4.
BACKGROUND: Recipients of hearts from donors with spontaneous intracerebral hemorrhage (ICH) are at increased risk of allograft vasculopathy compared with trauma donors. We have recently shown that the vitronectin receptor (integrin alpha(V)beta3) is upregulated in transplant vasculopathy. We hypothesized that donor ICH is associated with systemic activation of alpha(V)beta3 in the donor before transplantation. METHODS: We evaluated mRNA expressions of alpha(V)beta3 (TaqMan PCR) in endomyocardial biopsy samples at 1-week post-transplant in 20 recipients from ICH donors and 20 recipients from trauma donors. To investigate whether systemic activation of alpha(V)beta3 was present in the donor before transplantation, alpha(V)beta3 expression was also evaluated in the corresponding donor spleen lymphocytes. All patients underwent serial coronary intravascular ultrasound to evaluate for coronary vasculopathy. The baseline characteristics were similar except for increased donor age in the ICH Group. RESULTS: The ICH Group showed significant increased mRNA expression of alpha(V)beta3 in the heart biopsy samples (3.8-fold, p = 0.012) and in the corresponding donor spleen lymphocytes (3.5-fold, p = 0.014) compared with the Trauma Group. At 1 year, the ICH Group also showed increased progression of coronary vasculopathy. Multivariate regression analysis found that donor lymphocytic alpha(V)beta3 mRNA expression was independently associated with increased risk of vasculopathy (odds ratio, 1.9; 95% CI, 1.21-3.98, p = 0.03). CONCLUSIONS: Our report demonstrates the presence of systemic activation of alpha(V)beta3 in donors with spontaneous intracerebral hemorrhage and its association with the subsequent development of allograft vasculopathy in the recipient.  相似文献   
5.
BACKGROUND: The epidemiology of superficial venous disease is relatively well defined in the U.K. Caucasian population. By contrast, there are currently no data available for Asians, who comprise 3.6% of the U.K., and 14.1% of this institution's catchment population. The aim of this study was to compare surgery for superficial venous disease in Caucasians and Asians in this institution, in the context of our local population. METHODS: A prospectively gathered database of all 2011 superficial venous operations performed between January 1997 and April 2002 was retrospectively analysed with regard to ethnicity. The ethnic, gender and age composition of our catchment area was determined from U.K. census data. The full institutional records of 100 Asian and 100 randomly selected age and sex-matched Caucasian patients were compared in a case control study. RESULTS: After adjusting for age and gender according to census data, Asians were 40% less likely to undergo superficial venous surgery (SVS). Considering the 2011 operated patients as a whole, Asians were significantly younger and more likely to be male. In the case control study, Asians were significantly less likely to be operated for recurrent disease and significantly more likely to be operated for advanced disease. CONCLUSIONS: Although Asians are significantly less likely to undergo SVS; those that do are more likely to be young, male and operated for skin changes and ulcers. This strongly suggests that the under-representation of Asians is due to cultural, genetic or environmental factors and unmet health care need, rather than a lower prevalence of clinically significant venous disease in the Asian population.  相似文献   
6.
The pelvic congestion syndrome   总被引:4,自引:0,他引:4  
Perivulval varices appear during pregnancy and usually disappear after delivery but become more prominent with subsequent pregnancies. They may extend over the buttock and may be associated with recurrent leg varices. Some patients have extensive varices in the broad ligaments and present with the pelvic congestion syndrome. These patients have been shown to have grossly dilated ovarian veins. Elimination of this proximal incompetence relieves the symptoms.  相似文献   
7.
8.
Defecography in multiple sclerosis patients with severe constipation   总被引:3,自引:0,他引:3  
Gill  KP; Chia  YW; Henry  MM; Shorvon  PJ 《Radiology》1994,191(2):553
  相似文献   
9.
10.
Mercury sphygmomanometers have been commonly used in primary care to measure blood pressure but are associated with bias. Electronic blood pressure machines are being introduced in many practices and have anecdotally been associated with higher recorded blood pressure. This study examined recorded blood pressure in four practices before and after electronic blood pressure machine introduction. No consistent change in mean blood pressure was apparent following their introduction, but there was a large and significant fall in terminal digit preference suggesting improved precision of recording.  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