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   1771110篇
  免费   130779篇
  国内免费   8941篇
耳鼻咽喉   22279篇
儿科学   56556篇
妇产科学   47260篇
基础医学   250226篇
口腔科学   50212篇
临床医学   161127篇
内科学   345049篇
皮肤病学   39431篇
神经病学   135208篇
特种医学   66492篇
外国民族医学   274篇
外科学   264325篇
综合类   51698篇
现状与发展   18篇
一般理论   542篇
预防医学   129529篇
眼科学   42269篇
药学   131913篇
  87篇
中国医学   8759篇
肿瘤学   107576篇
  2021年   16758篇
  2019年   16045篇
  2018年   22628篇
  2017年   17628篇
  2016年   18888篇
  2015年   22434篇
  2014年   30424篇
  2013年   41870篇
  2012年   58601篇
  2011年   61628篇
  2010年   36798篇
  2009年   33866篇
  2008年   55729篇
  2007年   58836篇
  2006年   58932篇
  2005年   56147篇
  2004年   53316篇
  2003年   50471篇
  2002年   48469篇
  2001年   93275篇
  2000年   95195篇
  1999年   78687篇
  1998年   20903篇
  1997年   18462篇
  1996年   18331篇
  1995年   17662篇
  1994年   16043篇
  1993年   14538篇
  1992年   57844篇
  1991年   55704篇
  1990年   53331篇
  1989年   51063篇
  1988年   46374篇
  1987年   45170篇
  1986年   42390篇
  1985年   40127篇
  1984年   29436篇
  1983年   24969篇
  1982年   13941篇
  1979年   25559篇
  1978年   17588篇
  1977年   14917篇
  1976年   13883篇
  1975年   14572篇
  1974年   17642篇
  1973年   16953篇
  1972年   15682篇
  1971年   14458篇
  1970年   13443篇
  1969年   12519篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
91.
92.
93.
加强医疗仪器设备管理提高医疗仪器设备使用效益   总被引:1,自引:0,他引:1  
加强医疗设备管理,提高设备使用效益,制定合理的计划,正确选购设备,为医院提供品种、性能、精度适当的技术装备。  相似文献   
94.
95.
96.
In chronic myeloid leukaemia, CD34(+) stem/progenitor cells appear resistant to imatinib mesylate (IM) in vitro and in vivo. To investigate the underlying mechanism(s) of IM resistance, it is essential to quantify Bcr-Abl kinase status at the stem cell level. We developed a flow cytometry method to measure CrkL phosphorylation (P-CrkL) in samples with <10(4) cells. The method was first validated in wild-type (K562) and mutant (BAF3) BCR-ABL(+) as well as BCR-ABL(-) (HL60) cell lines. In response to increasing IM concentration, there was a linear reduction in P-CrkL, which was Bcr-Abl specific and correlated with known resistance. The results were comparable to those from Western blotting. The method also proved to be reproducible with small samples of normal and Ph(+) CD34(+) cells and was able to discriminate between Ph(-), sensitive and resistant Ph(+) cells. This assay should now enable investigators to unravel the mechanism(s) of IM resistance in stem cells.  相似文献   
97.
98.
Pre-eclamptic toxaemia (PET) may be associated with both endothelial dysfunction (ED) and sleep-disordered breathing (SDB). It was hypothesised that females with PET would demonstrate both SDB and ED, and that a correlation between these two would suggest a potential causative association. A total of 17 females with PET and 25 matched females with uncomplicated pregnancy were studied. They underwent a nocturnal ambulatory sleep study (using Watch_PAT100) and noninvasive evaluation of endothelial function utilising the reactive hyperaemia test (using Endo_PAT 2000). A higher ratio of post- to pre-occlusion pulse-wave amplitude (endothelial function index (EFI)) indicated better endothelial function. Females with PET had a significantly higher respiratory disturbance index (RDI) and lower EFI than controls (18.4+/-8.4 versus 8.3+/-1.3.h(-1), and 1.5+/-0.1 versus 1.8+/-0.1, respectively). Blood pressure significantly correlated with RDI and with EFI. EFI tended to correlate with RDI. In conclusion, these results suggest that both sleep-disordered breathing and endothelial dysfunction are more likely to occur in females with pre-eclamptic toxaemia than in females with uncomplicated pregnancies. The current authors speculate that respiratory disturbances contribute to the functional abnormality of the blood vessels seen in females with pre-eclamptic toxaemia, although causality cannot be determined based on this study.  相似文献   
99.
The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A subsidiary question was whether the results of a noninvasive measure of haemolysis (end-tidal carbon monoxide (ETCO) levels) correlated with pulmonary function abnormalities. Thirty three patients with SCD, median (range) age 36 yrs (17-67 yrs) were examined. The degree of lobar volume loss and ground-glass opacification and prominence of central vessels on HRCT were quantitatively assessed. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation. ETCO levels were measured using an end-tidal CO monitor. Forced expiratory volume in one second (FEV1), forced vital capacity and total lung capacity significantly correlated with HRCT findings, particularly lobar volume loss. ETCO levels significantly negatively correlated with FEV1, vital capacity measured using a plethysmograph, specific airway conductance and arterial oxygen saturation measured by pulse oxymetry. In conclusion, the present results suggest that high-resolution computed tomography noninvasive assessment of haemolysis might be useful to identify sickle cell disease patients with respiratory function impairment.  相似文献   
100.
Accurate assessment of the amount and intensity of physical activity in daily life is considered very important due to the close relationship between physical activity level, health, disability and mortality. For this reason, assessment of physical activity in daily life has gained interest in recent years, especially in sedentary populations, such as patients with chronic obstructive pulmonary disease (COPD). The present article aims to compare and discuss the two kinds of instruments more commonly used to quantify the amount of physical activity performed by COPD patients in daily life: subjective methods (questionnaires, diaries) and motion sensors (electronic or mechanical methods). Their characteristics are summarised and evidence of their validity, reliability and sensitivity is discussed, when available. Subjective methods have practical value mainly in providing the patients' view on their performance in activities of daily living and functional status. However, care must be taken when using subjective methods to accurately quantify the amount of daily physical activity performed. More accurate information is likely to be available with motion sensors rather than questionnaires. The selection of which motion sensor to use for quantification of physical activity in daily life should depend mainly on the purpose of its use.  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