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   2418915篇
  免费   198170篇
  国内免费   4408篇
耳鼻咽喉   34876篇
儿科学   73828篇
妇产科学   63807篇
基础医学   340513篇
口腔科学   68290篇
临床医学   219914篇
内科学   477416篇
皮肤病学   48572篇
神经病学   205026篇
特种医学   97411篇
外国民族医学   886篇
外科学   367526篇
综合类   56949篇
现状与发展   2篇
一般理论   1040篇
预防医学   194884篇
眼科学   56369篇
药学   180311篇
  4篇
中国医学   4440篇
肿瘤学   129429篇
  2018年   25068篇
  2017年   19418篇
  2016年   21310篇
  2015年   24092篇
  2014年   34795篇
  2013年   52792篇
  2012年   71440篇
  2011年   75222篇
  2010年   44138篇
  2009年   42403篇
  2008年   71394篇
  2007年   75829篇
  2006年   76697篇
  2005年   74806篇
  2004年   72114篇
  2003年   69527篇
  2002年   68715篇
  2001年   112804篇
  2000年   116819篇
  1999年   98768篇
  1998年   28404篇
  1997年   25991篇
  1996年   25876篇
  1995年   25025篇
  1994年   23531篇
  1993年   21869篇
  1992年   79657篇
  1991年   76643篇
  1990年   73807篇
  1989年   71075篇
  1988年   66081篇
  1987年   65004篇
  1986年   61528篇
  1985年   58636篇
  1984年   44593篇
  1983年   37957篇
  1982年   23291篇
  1981年   20741篇
  1980年   19442篇
  1979年   41496篇
  1978年   29221篇
  1977年   24565篇
  1976年   23006篇
  1975年   24152篇
  1974年   29839篇
  1973年   28182篇
  1972年   26369篇
  1971年   24275篇
  1970年   22836篇
  1969年   21163篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The acute recognition and management of CHF is challenging. A basic understanding of the determinants of cardiac performance and myocardial O2 consumption along with the pathophysiology of CHF is essential knowledge for the physician undertaking to treat this serious disorder. The basic value of the patient history and physical examination along with assessment of noninvasive tests remains unquestioned, but in addition much relevant and sophisticated information can be gained by invasive hemodynamic monitoring. The cardiopulmonary profile generated by such monitoring allows the physician to use specific hemodynamic and circulatory data for the purpose of manipulating these variables favorably for the heart and circulation. A wide array of therapeutic options is currently available, but, in general, respiratory support and pharmacotherapy are the mainstays of treatment. The traditional agents like digitalis and diuretics have assumed a lesser role during the last decade because of the availability of potent new vasodilator and inotropic agents. In addition, certain mechanical, procedural, and surgical options can be used if circumstances are urgent. In the final analysis, physicians who manage these patients must possess strong cognitive skills but also the clinical reflexes to carry them out: for every hemodynamic and circulatory action, they must be prepared to counter quickly and decisively with a clinical reaction which utilizes these principles to optimize cardiac function. It is hoped that the strategies presented in this article will allow them to perform in such a manner.  相似文献   
992.
A 41-year-old woman had acute hepatitis A infection complicated with severe anemia due to selective erythroblastopenia and hemolysis. A mechanism involving a cellular immune reaction is suggested. The hematological complications resolved during steroid treatment. She later developed a transient seropositive arthritis.  相似文献   
993.
OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported.  相似文献   
994.
995.
996.
Abstract: We have designed and synthesized a new series of azapeptides which act as potential inhibitors of cathepsin B and/or cathepsin K. Their structures are based upon the inhibitory sites of natural cysteine protease inhibitors, cystatins. For the synthesized azapeptides, the equilibrium constants for dissociation of inhibitor–enzyme complex, Ki, were determined. Comparison of these values indicated that all of the azainhibitors act much stronger toward cathepsin B. Z‐Arg‐Leu‐His‐Agly‐Ile‐Val‐OMe ( 7 ) proved to be approximately 500 times more potent for cathepsin B than for cathepsin K. To be able to explain the obtained experimental values we used the molecular dynamics procedures to analyze the interactions between cathepsin B and compound 7 . We also determined the structure of the most potent and selective cathepsin B azainhibitor by means of NMR studies and theoretical calculations. In this report, we describe SAR studies of azapeptide inhibitors indicating the influence of the conformational flexibility of the examined compounds on inhibition of cathepsins B and K.  相似文献   
997.
998.
It is usual at the end of a year for top tens to feature large in our collective consciousness. These inevitably include the occasional controversial selection and without fail will overlook a number of gems, whether in the field of literature, art, or science. The approaches to such compilations include personal selections, convening expert committees through to letting the market decide. However, it is well recognised that experts can be wrong and markets distorted. A novel approach to identifying the key publications in the field of medicine, Faculty of 1000 Medicine (http://www.f1000medicine.com), uses faculty evaluations to assign ratings to published papers within topics and categories, bringing a flavour of the dynamism of post hoc peer review to biological sciences that exists in other fields of scholarship. Archives of Disease in Childhood has also developed a market led system of peer evaluation through its web based top ten most read articles feature.  相似文献   
999.
1000.
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