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   613篇
  免费   45篇
  国内免费   1篇
耳鼻咽喉   7篇
儿科学   9篇
妇产科学   13篇
基础医学   79篇
口腔科学   5篇
临床医学   63篇
内科学   121篇
皮肤病学   18篇
神经病学   52篇
特种医学   41篇
外科学   51篇
综合类   4篇
一般理论   1篇
预防医学   107篇
药学   36篇
肿瘤学   52篇
  2023年   3篇
  2022年   3篇
  2021年   12篇
  2020年   5篇
  2019年   5篇
  2018年   15篇
  2017年   8篇
  2016年   16篇
  2015年   14篇
  2014年   12篇
  2013年   20篇
  2012年   42篇
  2011年   54篇
  2010年   20篇
  2009年   10篇
  2008年   33篇
  2007年   30篇
  2006年   43篇
  2005年   42篇
  2004年   53篇
  2003年   59篇
  2002年   52篇
  2001年   8篇
  2000年   8篇
  1999年   12篇
  1998年   9篇
  1997年   10篇
  1996年   2篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1990年   4篇
  1988年   3篇
  1987年   3篇
  1986年   3篇
  1983年   4篇
  1982年   4篇
  1974年   2篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
  1960年   1篇
  1954年   1篇
  1945年   1篇
  1931年   2篇
  1930年   2篇
  1928年   2篇
  1925年   1篇
  1923年   2篇
  1918年   1篇
排序方式: 共有659条查询结果,搜索用时 15 毫秒
11.
A previous publication presented normative data on neuropsychological tests stratified by age, gender, and education based on the Original Cohort of the Framingham Heart Study. Many contemporary investigations include subject samples with higher levels of education, a factor known to affect cognitive performance. Secular change in education prompted the reexamination of norms in the children of the Original Cohort. The study population consisted of 853 men and 988 women from the Offspring Study, free of clinical neurological disease, who underwent a neuropsychological examination, which included tests given to their parents in 1974 to 1976 as well as additional newer tests to provide a more comprehensive battery. The Offspring population overall was more evenly distributed by gender and better educated. Their performance on cognitive tests was superior to that of the Original Cohort. Multivariable analyses revealed that more years of education explained only a part of the cohort differences. These findings suggest that continued surveillance of each generation is necessary to document the impact that unique social and economic variables have on cognitive function. Here, the authors provide updated normative data.  相似文献   
12.
Polycystic ovarian syndrome (PCOS) is the most frequent endocrine disorder of reproductive age women, affecting an estimated 8-10% of all women in this age group or approximately six million women. Further, women with PCOS continue to manifest the metabolic alterations inherent in the insulin resistance syndrome after menopause, rendering them more susceptible to type 2 diabetes and cardiovascular disease. Aging and obesity further contribute to these risks. Since estrogen-containing therapy is commonly used for menstrual regulation in premenopausal women with PCOS, it is important to evaluate the possible consequences of hormonal therapy on subsequent metabolic and cardiovascular risk. In postmenopausal women, a consensus regarding the appropriate role of estrogen replacement therapy is currently in evolution. By examining the effects of estrogen with or without progesterone on insulin resistance, insight may be gained about the risk/benefit ratio of this therapy in the subset of women with insulin resistance, PCOS, and type 2 diabetes. The goal of this review, then, is to examine the known effects of estrogen on insulin sensitivity and its implications for cardiovascular and metabolic risk.  相似文献   
13.
The association of human immunodeficiency virus (HIV) acquisition with herpes simplex virus type 2 (HSV-2) was assessed among men who have sex with men (MSM) in a nested case-control study of 116 case subjects who seroconverted to HIV during follow-up and 342 control subjects who remained HIV seronegative, frequency-matched by follow-up duration and report of HIV-infected sex partner and unprotected anal sex. The baseline HSV-2 seroprevalence was higher among case (46%) than control (34%) subjects (P=.03); the HSV-2 seroincidence was 7% versus 4% (P=.3). Only 15% of HSV-2-infected MSM reported herpes outbreaks in the past year. HIV acquisition was associated with prior HSV-2 infection (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-2.9), reporting >12 sex partners (OR, 2.9; 95% CI, 1.4-6.3), and reporting fewer herpes outbreaks in the past year (OR, 0.3; 95% CI, 0.1-0.8). HSV-2 increases the risk of HIV acquisition, independent of recognized herpes lesions and behaviors reflecting potential HIV exposure. HSV-2 suppression with antiviral therapy should be evaluated as an HIV prevention strategy among MSM.  相似文献   
14.
15.
16.
17.
18.
19.
A large body of behavioural research has used the cued task‐switching paradigm to characterize the nature of trial‐by‐trial preparatory adjustments that enable fluent task implementation when demands on cognitive flexibility are high. This work reviews the growing number of fMRI studies on the same topic, mostly focusing on the central hypothesis that preparatory adjustments should be indicated by enhanced prefrontal and parietal BOLD activation in task switch when compared with task repeat trials under conditions that enable advance task preparation. The evaluation of this straight‐forward hypothesis reveals surprisingly heterogeneous results regarding both the precise localization and the very existence of switch‐related preparatory activation. Explanations for these inconsistencies are considered on two levels. First, we discuss methodological issues regarding (i) the possible impact of different fMRI‐specific experimental design modifications and (ii) statistical uncertainty in the context of massively multivariate imaging data. Second, we discuss explanations related to the multidimensional nature of task preparation itself. Specifically, the precise localization and the size of switch‐related preparatory activation might depend on the differential interplay of hierarchical control via abstract task goals and attentional versus action‐directed preparatory processes. We argue that different preparatory modes can be adopted relying either on advance goal activation alone or on the advance resolution of competition within action sets or attentional sets. Importantly, while either mode can result in a reduction of behavioral switch cost, only the latter two are supposed to be associated with enhanced switch versus repeat BOLD activation in prepared trial conditions. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.  相似文献   
20.
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