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   9759篇
  免费   923篇
  国内免费   83篇
耳鼻咽喉   81篇
儿科学   382篇
妇产科学   127篇
基础医学   1382篇
口腔科学   202篇
临床医学   1261篇
内科学   1931篇
皮肤病学   210篇
神经病学   792篇
特种医学   599篇
外科学   1242篇
综合类   266篇
一般理论   7篇
预防医学   1204篇
眼科学   127篇
药学   499篇
  3篇
中国医学   8篇
肿瘤学   442篇
  2021年   119篇
  2020年   72篇
  2019年   130篇
  2018年   139篇
  2017年   131篇
  2016年   105篇
  2015年   150篇
  2014年   171篇
  2013年   306篇
  2012年   361篇
  2011年   392篇
  2010年   293篇
  2009年   273篇
  2008年   396篇
  2007年   387篇
  2006年   377篇
  2005年   367篇
  2004年   320篇
  2003年   263篇
  2002年   308篇
  2001年   307篇
  2000年   299篇
  1999年   264篇
  1998年   226篇
  1997年   242篇
  1996年   191篇
  1995年   166篇
  1994年   164篇
  1993年   166篇
  1992年   219篇
  1991年   217篇
  1990年   227篇
  1989年   227篇
  1988年   213篇
  1987年   201篇
  1986年   211篇
  1985年   209篇
  1984年   147篇
  1983年   123篇
  1982年   108篇
  1981年   110篇
  1980年   97篇
  1979年   80篇
  1978年   93篇
  1977年   76篇
  1976年   87篇
  1975年   65篇
  1974年   74篇
  1973年   59篇
  1971年   68篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
2.
In this new colorimetric assay for Factor XIII in plasma, 5-(biotinamido)pentylamine is used as the amine substrate. Factor XIII, a zymogen, is transformed by thrombin and Ca2+ to active Factor XIIIa, and the incorporation of 5-(biotinamido)pentylamine into N,N-dimethylcasein is used to measure catalytically active Factor XIIIa. The biotinylated enzymatic product is immobilized onto 96-well microtiter plates, complexed with streptavidin-beta-galactosidase, and the absorbance at 405 nm is monitored for production of p-nitrophenol from p-nitrophenyl-beta-D-galactopyranoside. Concentrations of N,N-dimethylcasein, 5-(biotinamido)pentylamine, Ca2+, and thrombin were chosen to allow near-maximum velocity of amine incorporation. A linear relationship was obtained between assay product and plasma volume, from 0.5 to 50 microL of plasma. Results correlated well (r greater than 0.924) with those from the most frequently utilized radiometric filter-paper assay for Factor XIII. The method appears to be ideal for routine diagnostic estimation of Factor XIII in plasma because of its simplicity, its lack of use of radioisotopes, and its potential for assay of large numbers of samples by use of microtiter plates and automated plate readers.  相似文献   
3.
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2, PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α.  相似文献   
4.
Promoting the health of senior citizens   总被引:1,自引:0,他引:1       下载免费PDF全文
Canada is experiencing a dramatic increase in the number of older people in its population. Adopting strategies that involve physician actions, a societal approach and individual participation may substantially improve the health of senior citizens. This article presents ways to improve the quality of life and reduce the risk of premature death through manoeuvres that can be initiated by physicians in the context of the periodic health examination. The authors highlight the role of evidence in choosing the most appropriate interventions, speculate on areas of future importance and emphasize a societal approach to population health.  相似文献   
5.
6.
7.
8.
9.
10.
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