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   2572510篇
  免费   198753篇
  国内免费   4350篇
耳鼻咽喉   35758篇
儿科学   80049篇
妇产科学   66913篇
基础医学   356019篇
口腔科学   70070篇
临床医学   230742篇
内科学   503850篇
皮肤病学   49238篇
神经病学   219057篇
特种医学   105496篇
外国民族医学   907篇
外科学   391153篇
综合类   58868篇
现状与发展   1篇
一般理论   1028篇
预防医学   210284篇
眼科学   58858篇
药学   188963篇
  4篇
中国医学   5096篇
肿瘤学   143259篇
  2018年   44547篇
  2017年   34760篇
  2016年   38518篇
  2015年   25042篇
  2014年   35421篇
  2013年   53520篇
  2012年   77577篇
  2011年   93406篇
  2010年   60581篇
  2009年   52563篇
  2008年   88114篇
  2007年   94437篇
  2006年   76832篇
  2005年   76190篇
  2004年   74643篇
  2003年   72764篇
  2002年   70353篇
  2001年   113620篇
  2000年   117843篇
  1999年   99388篇
  1998年   28605篇
  1997年   26104篇
  1996年   25865篇
  1995年   25050篇
  1994年   23570篇
  1993年   21882篇
  1992年   80000篇
  1991年   77027篇
  1990年   74231篇
  1989年   71468篇
  1988年   66346篇
  1987年   65276篇
  1986年   61741篇
  1985年   58837篇
  1984年   44534篇
  1983年   37956篇
  1982年   23135篇
  1981年   20552篇
  1980年   19268篇
  1979年   41607篇
  1978年   29179篇
  1977年   24530篇
  1976年   22982篇
  1975年   24137篇
  1974年   29859篇
  1973年   28226篇
  1972年   26381篇
  1971年   24309篇
  1970年   22907篇
  1969年   21214篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
61.
Contour defects resulting in deformity caused by lack of tissue can be improved by conventional surgery using autologous tissue, but there is always a donor site morbidity. Integra has been available since the early 1980's for use in acute burns and more recently in reconstruction. It has been shown histologically to act as a tissue regeneration template. The regenerated dermis is buried under an autologous thin split-skin graft. In this study, the principle of burying Integra (without the silicone layer) has been applied to deep tissue defects in 12 reconstructive cases. Such regenerated tissues survive at least 3 years after burying. Modification to the technique to avoid visible edges are being developed.  相似文献   
62.
63.
64.
65.
66.
67.
We evaluated the acquisition and performance of a high-precision locomotor task in patients with Parkinson's disease (PD) and healthy subjects. All subjects walked on a treadmill and had to step repetitively as low as possible over an obstacle without touching it. During blocks 1 and 2, the subjects had full vision and received additional acoustic warning and feedback signals. During block 3, vision became restricted. Changes in foot clearance and the number of obstacle hits were evaluated. Initially, PD patients performed poorer and improved foot clearance slower. After task repetition, the groups performed similarly. Restricting vision deteriorated performance in both groups. The similar performance of PD patients after task repetition might indicate that adequate training could improve adaptive locomotor behavior in PD patients.  相似文献   
68.
An increase in chronic beryllium disease (CBD) has been suggested due to higher industrial use of beryllium alloys. Since occupational CBD is a perfect phenocopy of sarcoidosis, it might be misdiagnosed as sarcoidosis. In the current it was hypothesised that CBD exists in cohorts of sarcoidosis patients. In a prospective case study, sarcoidosis patients were evaluated for potential beryllium exposure. In those patients in whom beryllium exposure was confirmed and beryllium hypersensitivity demonstrated, the diagnosis of sarcoidosis was rejected and corrected to CBD. In 84 patients seen for re-evaluation or making a diagnosis of sarcoidosis, beryllium exposure was recognised and a diagnosis of CBD was made in 34 out of 84 patients. The time lag between clinical diagnosis of sarcoidosis and the final diagnosis of CBD ranged 0-18 yrs (median 3 yrs) and the mean (range) age at time of diagnosis of CBD was 43.9(25-80) yrs. Beryllium-contaminated workplaces causing disease encompassed a wide spectrum of industries and technical trades in which beryllium-exposure is generally not perceived as a health hazard. In conclusion, chronic beryllium disease still belongs to the spectrum of differential diagnoses of granulomatous disorders.  相似文献   
69.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.  相似文献   
70.
Summary:  The immune system is capable of recognizing and eliminating an enormous array of pathogens due to the extremely diverse antigen receptor repertoire of T and B lymphocytes. However, the development of lymphocytes bearing receptors with unique specificities requires the generation of programmed double strand breaks (DSBs) coupled with bursts of proliferation, rendering lymphocytes susceptible to mutations contributing to oncogenic transformation. Consequently, mechanisms responsible for monitoring global genomic integrity must be activated during lymphocyte development to limit the oncogenic potential of antigen receptor locus recombination. Mutations in ATM (ataxia-telangiectasia mutated), a kinase that coordinates DSB monitoring and the response to DNA damage, result in impaired T-cell development and predispose to T-cell leukemia. Here, we review recent evidence providing insight into the mechanisms by which ATM promotes normal lymphocyte development and protects from neoplastic transformation.  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