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   3227592篇
  免费   255860篇
  国内免费   5565篇
耳鼻咽喉   45869篇
儿科学   101537篇
妇产科学   87203篇
基础医学   464487篇
口腔科学   93175篇
临床医学   299160篇
内科学   624107篇
皮肤病学   66720篇
神经病学   269822篇
特种医学   126329篇
外国民族医学   1109篇
外科学   476188篇
综合类   73957篇
现状与发展   5篇
一般理论   1492篇
预防医学   267255篇
眼科学   75910篇
药学   240463篇
  10篇
中国医学   5852篇
肿瘤学   168367篇
  2018年   33862篇
  2017年   26139篇
  2016年   28811篇
  2015年   32766篇
  2014年   46700篇
  2013年   70909篇
  2012年   96086篇
  2011年   101775篇
  2010年   59544篇
  2009年   57191篇
  2008年   96328篇
  2007年   102611篇
  2006年   102862篇
  2005年   100338篇
  2004年   96276篇
  2003年   92743篇
  2002年   91118篇
  2001年   143960篇
  2000年   148478篇
  1999年   125825篇
  1998年   37083篇
  1997年   33537篇
  1996年   33539篇
  1995年   32064篇
  1994年   30166篇
  1993年   28194篇
  1992年   101565篇
  1991年   98686篇
  1990年   95438篇
  1989年   92066篇
  1988年   85612篇
  1987年   84117篇
  1986年   79993篇
  1985年   76294篇
  1984年   57992篇
  1983年   50105篇
  1982年   30322篇
  1981年   27142篇
  1979年   54897篇
  1978年   39156篇
  1977年   32940篇
  1976年   30803篇
  1975年   32777篇
  1974年   40227篇
  1973年   38676篇
  1972年   36484篇
  1971年   33861篇
  1970年   31829篇
  1969年   29782篇
  1968年   27331篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Caring for patients with end-stage kidney disease (ESKD) in the United States is challenging, due in part to the complex epidemiology of the disease's progression as well as the ways in which care is delivered. As CKD progresses toward ESKD, the number of comorbidities increases and care involves multiple healthcare providers from multiple subspecialties. This occurs in the context of a fragmented US healthcare delivery system that is traditionally siloed by provider specialty, organization, as well as systems of payment and administration. This article describes the role of care fragmentation in the delivery of optimal ESKD care and identifies research gaps in the evidence across the continuum of care. We then consider the impact of care fragmentation on ESKD care from the patient and health system perspectives and explore opportunities for system-level interventions aimed at improving care for patients with ESKD.  相似文献   
102.
103.
As millions of people turn to social media for health information, better understanding the factors that guide health-related judgments and perceptions in this context is imperative. We report on two Web experiments (n > 400 total) examining the power of society’s widespread weight bias and related stereotypes to influence nutrition judgments in social media spaces. In Experiment 1, meals were judged as lower in nutritional quality when the person who recommended them (the source) was depicted as obese rather than of normal weight, an effect mediated by stereotypic beliefs about the source as a generally unhealthy person. Experiment 2 replicated this effect, which—notably—remained significant when controlling for objective nutritional information (calories and fat content). Results highlight spillover effects of weight bias that extend beyond person perception to color impressions of objects (here, food) that are associated with stigmatized attributes. Implications for everyday nutrition judgments and public health are considered.  相似文献   
104.
105.
106.
107.
108.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
109.
110.
The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val158Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 healthy adult participants, who were also assessed on standard working memory (WM) tasks. Relative to Val carriers, Met homozygotes made fewer errors when selecting and manipulating self-generated thoughts. This effect was partly accounted for by an association between COMT genotype and visuospatial WM performance. We also observed a complex interaction between the influence of affective distractors, COMT genotype and sex on task accuracy: male, but not female, participants showed a sensitivity to the affective distractors that was dependent on COMT genotype. This was not accounted for by WM performance. This study provides novel evidence of the role of dopaminergic genetic variation on the ability to select and manipulate self-generated thoughts. The results also suggest sexually dimorphic effects of COMT genotype on the influence of affective distractors on executive function.  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