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   1546030篇
  免费   134349篇
  国内免费   21472篇
耳鼻咽喉   18519篇
儿科学   45084篇
妇产科学   39362篇
基础医学   208787篇
口腔科学   39820篇
临床医学   150624篇
内科学   309196篇
皮肤病学   33973篇
神经病学   122178篇
特种医学   63432篇
外国民族医学   412篇
外科学   230727篇
综合类   66427篇
现状与发展   57篇
一般理论   433篇
预防医学   119118篇
眼科学   34553篇
药学   115596篇
  199篇
中国医学   14499篇
肿瘤学   88855篇
  2021年   19893篇
  2020年   13667篇
  2019年   16434篇
  2018年   21195篇
  2017年   17536篇
  2016年   19227篇
  2015年   24263篇
  2014年   32147篇
  2013年   40086篇
  2012年   51732篇
  2011年   56341篇
  2010年   34626篇
  2009年   31834篇
  2008年   47068篇
  2007年   49434篇
  2006年   50702篇
  2005年   49482篇
  2004年   43442篇
  2003年   42162篇
  2002年   39072篇
  2001年   70374篇
  2000年   72687篇
  1999年   61802篇
  1998年   20083篇
  1997年   18406篇
  1996年   18729篇
  1995年   18765篇
  1994年   17169篇
  1993年   15467篇
  1992年   48779篇
  1991年   47180篇
  1990年   45092篇
  1989年   42759篇
  1988年   39627篇
  1987年   38804篇
  1986年   36481篇
  1985年   35072篇
  1984年   26643篇
  1983年   22306篇
  1982年   13972篇
  1981年   12572篇
  1979年   23661篇
  1978年   17109篇
  1977年   14426篇
  1976年   13206篇
  1975年   13766篇
  1974年   16139篇
  1973年   15430篇
  1972年   14210篇
  1971年   13060篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
85.
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose embryo-related genetic abnormalities for couples who present a high risk of a specific inherited disorder. Because this technology involves embryo selection, the medical, bioethical, and legal implications of the technique have been debated, particularly when it is used to select features that are not related to serious diseases. Although several initiatives have attempted to achieve regulatory harmonization, the diversity of healthcare services available and the presence of cultural differences have hampered attempts to achieve this goal. Thus, in different countries, the provision of PGD and regulatory frameworks reflect the perceptions of scientific groups, legislators, and society regarding this technology. In Brazil, several texts have been analyzed by the National Congress to regulate the use of assisted reproduction technologies. Legislative debates, however, are not conclusive, and limited information has been published on how PGD is specifically regulated. The country requires the development of new regulatory standards to ensure adequate access to this technology and to guarantee its safe practice. This study examined official documents published on PGD regulation in Brazil and demonstrated how little direct oversight of PGD currently exists. It provides relevant information to encourage reflection on a particular regulation model in a Brazilian context, and should serve as part of the basis to enable further reform of the clinical practice of PGD in the country.  相似文献   
86.
A 42‐year‐old man presented with a viral prodrome and tested positive for influenza A. He rapidly deteriorated developing cardiogenic shock, rhabdomyolysis, and acute kidney injury. Patient improved 1 week later with supportive measures including vasopressors, inotropes, and an intraaortic balloon pump. We report this case as it highlights the discordance between echocardiographic ventricular wall thickening as a result of myocardial edema, and electrocardiographic findings at presentation, with a reversal in findings at time of resolution. Additionally, there was some suggestion of a regional pattern to the reduced longitudinal strain.  相似文献   
87.
BACKGROUND Metabolic disturbances including changes in serum calcium,magnesium or phosphate(P) influence the prevalence of type 2 diabetes mellitus(DM).We assessed the importance of serum P in elderly patients with type 2 DM vs nondiabetes mellitus(non-DM) in relation to renal function.AIM To determine the association between serum P and serum glucose or insulin resistance in diabetic and non-diabetic patients.METHODS One hundred-ten subjects with a mean age of 69.02±14.3 years were enrolled.Twenty-nine of the participants had type 2 DM(26.4%).The incidence of hypertension,smoking and receiving vitamin D(vitD) derivates were recorded.The participants were classified by both estimated glomerular filtration rate(eGFR) and albuminuria categories according to the Kidney Disease Improving Global Outcomes 2012 criteria.RESULTS We divided the patients in two groups according to the P cut-off point related to DM value.A comparison between high and low P showed that body mass index30.2±6.3 vs 28.1±4.6(P=0.04),mean glucose 63.6 vs 50.2(P=0.03),uric acid 6.7±1.6 vs 6.09±1.7(P=0.05),mean intact-parathyroid hormone 68.06 vs 47.4(P=0.001),systolic blood pressure 147.4±16.7 vs 140..2±16.1(P=0.02),mean albuminuria 63.2 vs 50.6(P=0.04) and eGFR 45.6±22.1 vs 55.4±21.5(P=0.02)were significantly different.χ~2 tests showed a significant association between high P and DM,hypertension,receiving vitD,smoking and eGFR stage(χ~2=6.3,P=0.01,χ~2=3.9,P=0.03,χ~2=6.9,P=0.009,χ~2=7.04,P=0.01 and χ~2=7.36,P=0.04,respectively).The adjusted model showed that older age,female gender and increased body mass index were significant predictors of type 2 DM when entering the covariates.CONCLUSION High serum P contributes to vascular and metabolic disturbances in elderly patients with type 2 DM and renal impairment.  相似文献   
88.
89.
90.
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