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   2298篇
  免费   129篇
  国内免费   66篇
耳鼻咽喉   16篇
儿科学   166篇
妇产科学   70篇
基础医学   265篇
口腔科学   54篇
临床医学   180篇
内科学   382篇
皮肤病学   32篇
神经病学   215篇
特种医学   335篇
外科学   312篇
综合类   106篇
预防医学   70篇
眼科学   15篇
药学   150篇
中国医学   20篇
肿瘤学   105篇
  2023年   6篇
  2022年   13篇
  2021年   43篇
  2020年   15篇
  2019年   26篇
  2018年   54篇
  2017年   47篇
  2016年   56篇
  2015年   46篇
  2014年   98篇
  2013年   101篇
  2012年   110篇
  2011年   129篇
  2010年   87篇
  2009年   104篇
  2008年   101篇
  2007年   118篇
  2006年   96篇
  2005年   95篇
  2004年   60篇
  2003年   48篇
  2002年   72篇
  2001年   64篇
  2000年   48篇
  1999年   67篇
  1998年   71篇
  1997年   66篇
  1996年   63篇
  1995年   64篇
  1994年   38篇
  1993年   47篇
  1992年   29篇
  1991年   25篇
  1990年   30篇
  1989年   60篇
  1988年   40篇
  1987年   38篇
  1986年   18篇
  1985年   24篇
  1984年   14篇
  1983年   11篇
  1982年   19篇
  1981年   21篇
  1980年   23篇
  1979年   17篇
  1978年   9篇
  1977年   18篇
  1976年   10篇
  1975年   13篇
  1972年   3篇
排序方式: 共有2493条查询结果,搜索用时 15 毫秒
61.
Journal of Digital Imaging - Cardiovascular diseases (CVDs) are the top ten leading causes of death worldwide. Atherosclerosis disease in the arteries is the main cause of the CVD, leading to...  相似文献   
62.
63.
64.
The anatomical knowledge of arterial variations of lower limb is of utmost significance for the present day surgeons and interventional radiologists for minimizing complications during vascular reconstructive procedures, catheterization procedures and surgical intervention for embolism. Lateral Circumflex Femoral Artery(LCFA) isan important branch of Profunda Femoris artery and precise knowledge of its variations can be of great relevance during surgical and radiological procedures in femoral region. The present study reports a unique case of anomalous route taken by LCFA posterior to femoral nerve associated with a prominent muscular branch from Femoral artery mimicking the course of LCFA. Documentation of such variations is highly significant. It may serve as guideline for surgeons in reducing the incidence of postoperative complications where LCFA is used as a long vascular pedicle in anterolateral perforator thigh flap and in breast reconstruction after mastectomy. Ignorance of such variations can lead to fatal intraoperative haemorrhage and incapacitating sensory and motor deficit due to injury to femoral nerve branches which are closely related to these vessels.  相似文献   
65.
Heeb  MJ; Kojima  Y; Greengard  JS; Griffin  JH 《Blood》1995,85(12):3405-3411
Gln506-factor V (FV) was purified from plasma of an individual homozygous for an Arg506Gln mutation in FV that is associated with activated protein C (APC) resistance. Purified Gln506-FV, as well as Gln506-FVa generated by either thrombin or FXa, conveyed APC resistance to FV-deficient plasma in coagulation assays. Clotting assay studies also suggested that APC resistance does not involve any abnormality in FV-APC-cofactor activity. In purified reaction mixtures, Gln506-FVa in comparison to normal FVa showed reduced susceptibility to APC, because it was inactivated approximately 10-fold slower than normal Arg506-FVa. It was previously reported that inactivation of normal FVa by APC involves an initial cleavage at Arg506 followed by phospholipid- dependent cleavage at Arg306. Immunoblot and amino acid sequence analyses showed that the 102-kD heavy chain of Gln506-FVa was cleaved at Arg306 during inactivation by APC in a phospholipid-dependent reaction. This reduced but measurable susceptibility of Gln506-FVa to APC inactivation may help explain why APC resistance is a mild risk factor for thrombosis because APC can inactivate both normal FVa and variant Gln506-FVa. In summary, this study shows that purified Gln506- FV can account for APC resistance of plasma because Gln506-FVa, whether generated by thrombin or FXa, is relatively resistant to APC.  相似文献   
66.
67.
Dermatomyositis with HIV infection has been very rarely reported. The authors report an 8-y-old boy who presented with skin rashes and edema, muscle weakness and polymicrobial infection along with mild immunosupression. Diagnosis of dermatomyositis was established by raised enzymes, suggestive MRI and muscle biopsy findings. Child responded to systemic steroids and low dose weekly methotrexate.  相似文献   
68.
69.
The natural tendency for humans to make and break relationships is thought to facilitate the emergence of cooperation. In particular, allowing conditional cooperators to choose with whom they interact is believed to reinforce the rewards accruing to mutual cooperation while simultaneously excluding defectors. Here we report on a series of human subjects experiments in which groups of 24 participants played an iterated prisoner's dilemma game where, critically, they were also allowed to propose and delete links to players of their own choosing at some variable rate. Over a wide variety of parameter settings and initial conditions, we found that dynamic partner updating significantly increased the level of cooperation, the average payoffs to players, and the assortativity between cooperators. Even relatively slow update rates were sufficient to produce large effects, while subsequent increases to the update rate had progressively smaller, but still positive, effects. For standard prisoner's dilemma payoffs, we also found that assortativity resulted predominantly from cooperators avoiding defectors, not by severing ties with defecting partners, and that cooperation correspondingly suffered. Finally, by modifying the payoffs to satisfy two novel conditions, we found that cooperators did punish defectors by severing ties, leading to higher levels of cooperation that persisted for longer.  相似文献   
70.
The birth and explosive growth of mobile money in Kenya has provided economists with an opportunity to study the evolution and impact of a new financial system. Mobile money is an innovation that allows individuals to store, send, and receive money on their mobile phone via text message. This system has opened up basic financial services to many who were previously excluded, and has had real and measurable impacts on the ability of households to protect themselves against health risks. Using a unique survey instrument covering nearly 2,300 households over 2008-2010, we first document the lightning-fast adoption of mobile money in Kenya, which was faster than most documented modern technologies in the United States. We then present evidence on how this innovation allows households to respond better to unexpected adverse health events. We find that in the face of these events, users of mobile money are better able to tap into remittances to finance additional health care costs without having to forego necessary expenditures on education, food, and other consumption needs.  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