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   997640篇
  免费   75073篇
  国内免费   2616篇
耳鼻咽喉   12962篇
儿科学   34464篇
妇产科学   28463篇
基础医学   145296篇
口腔科学   27714篇
临床医学   90277篇
内科学   193555篇
皮肤病学   22912篇
神经病学   79117篇
特种医学   38387篇
外国民族医学   305篇
外科学   149495篇
综合类   23739篇
一般理论   385篇
预防医学   77824篇
眼科学   22606篇
药学   71867篇
  3篇
中国医学   2029篇
肿瘤学   53929篇
  2018年   10555篇
  2017年   8235篇
  2016年   9376篇
  2015年   10595篇
  2014年   14418篇
  2013年   22004篇
  2012年   28985篇
  2011年   30827篇
  2010年   18488篇
  2009年   17439篇
  2008年   28788篇
  2007年   30463篇
  2006年   30963篇
  2005年   29637篇
  2004年   28925篇
  2003年   27800篇
  2002年   26813篇
  2001年   46926篇
  2000年   48033篇
  1999年   40262篇
  1998年   11177篇
  1997年   10095篇
  1996年   10162篇
  1995年   9776篇
  1994年   9092篇
  1993年   8480篇
  1992年   32253篇
  1991年   31460篇
  1990年   31006篇
  1989年   29876篇
  1988年   27168篇
  1987年   27326篇
  1986年   25434篇
  1985年   24604篇
  1984年   18397篇
  1983年   15516篇
  1982年   9293篇
  1981年   8375篇
  1979年   16859篇
  1978年   12218篇
  1977年   10314篇
  1976年   9755篇
  1975年   10178篇
  1974年   12318篇
  1973年   11845篇
  1972年   10885篇
  1971年   10114篇
  1970年   9375篇
  1969年   8728篇
  1968年   8104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Digestive Diseases and Sciences - To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be...  相似文献   
93.
94.
95.
96.
This study qualitatively examined factors that influenced contraceptive choices in a sample of young, HIV-infected women. Individual qualitative interviews were conducted among 30 vertically and horizontally HIV-infected women (= 26 African American) from the ages of 14 to 24 years (Mean age = 20.9 years). We recruited sample groups with the following characteristics: (a) current contraceptive/condom use with ≥1 child (= 11); (b) current contraceptive/condom use with no children (= 12); and (c) no current contraceptive/condom use with no children (= 7). A semi-structured interview guide was used to ask participants about factors influencing past and current contraceptive choices. Individual interviews were digitally recorded and transcribed verbatim; analyses to identify core themes were informed by the Grounded Theoretical approach. Young, HIV-infected women did not identify their HIV serostatus or disease-related concerns as influential in their contraceptive decisions. However, they reported that recommendations from health-care providers and input from family and friends influenced their contraceptive choices. They also considered a particular method’s advantages (e.g., menstrual cycle improvements) and disadvantages (e.g., increased pill burden) when selecting a method. Findings suggested that HIV-infected young women’s contraceptive decisions were influenced by factors other than those related to their infection.  相似文献   
97.

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

Methods and results

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

Conclusion

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.  相似文献   
98.
99.
100.
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