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   193017篇
  免费   2275篇
  国内免费   45篇
耳鼻咽喉   1241篇
儿科学   7149篇
妇产科学   3503篇
基础医学   19163篇
口腔科学   1874篇
临床医学   14371篇
内科学   34356篇
皮肤病学   978篇
神经病学   18391篇
特种医学   9465篇
外科学   30370篇
综合类   2471篇
现状与发展   1篇
一般理论   20篇
预防医学   19924篇
眼科学   3014篇
药学   10816篇
中国医学   679篇
肿瘤学   17551篇
  2024年   27篇
  2023年   249篇
  2022年   389篇
  2021年   687篇
  2020年   473篇
  2019年   768篇
  2018年   22532篇
  2017年   17851篇
  2016年   19975篇
  2015年   1501篇
  2014年   1574篇
  2013年   1778篇
  2012年   8542篇
  2011年   22477篇
  2010年   19514篇
  2009年   12222篇
  2008年   20614篇
  2007年   22833篇
  2006年   1524篇
  2005年   3211篇
  2004年   4270篇
  2003年   5113篇
  2002年   3219篇
  2001年   416篇
  2000年   496篇
  1999年   279篇
  1998年   321篇
  1997年   324篇
  1996年   164篇
  1995年   172篇
  1994年   161篇
  1993年   113篇
  1992年   85篇
  1991年   123篇
  1990年   169篇
  1989年   111篇
  1988年   97篇
  1987年   81篇
  1986年   64篇
  1985年   56篇
  1984年   40篇
  1983年   33篇
  1982年   55篇
  1981年   29篇
  1980年   50篇
  1938年   60篇
  1937年   27篇
  1934年   30篇
  1932年   57篇
  1930年   47篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Ohne Zusammenfassung  相似文献   
82.
83.
84.
When children are ill enough to require admission to paediatric intensive care, parents may become distressed about their child's medical condition and this distress may be compounded by the unfamiliar nature of the highly technological environment Parents of children who are sick enough to warrant intubation are particularly likely to be exposed to a frightening array of technological equipment Seventy-one parents of intubated and non-intubated children completed the Parental Stressor Scale Paediatnc Intensive Care Unit (PSS PICU) Overall the findings suggest that parents were most distressed (a) by the painful procedures to which their children were subjected, (b) by the sights and sounds of the intensive care unit and (c) by their children's reactions to intensive care The behaviour of staff towards parents and the way that staff communicated with them caused the least distress When the levels of stress reported by parents of intubated children were compared with those reported by parents of non-intubated children, different patterns of stress were found Painful procedures were a source of greater stress to parents of intubated children whereas the behaviour of staff and the children's reactions to the intensive care experience caused greater stress to the parents of the non-intubated children In general the findings suggest that the needs of parents of non-intubated children are being overlooked, with staff focusing more of their attention on the parents of intubated children  相似文献   
85.
Electrostatic effects play an important role in protein interactions and may alter the biodistribution of antibodies. To study the effect of molecular charge on the biodistribution and infection imaging properties of human polyclonal immunoglobulin G (IgG), its iso electric point was varied by changing the level of diethylene triamine penta-acetic acid (DTPA) substitution: 0.8, 0.9, 3.7, 5.1 and 5.9 DTPA/IgG. Biodistributions of the different IgG preparations were determined at 10 min, 1, 6, 24, and 48 h post injection in normal rats, and infection imaging properties were determined in rats withEscherichia coli thigh infections. The biodistribution was significantly affected by pl. The immunoglobulin preparations with 0.9 and 3.7 DTPA/IgG showed faster clearance from the circulation and generally lower accumulation in most organs. The images had a target-to-background ratio of approximately 1.3–2.3:1. These results suggest that even though targeting is not affected by the level of DTPA substitutions, preparations with 0.9 and 3.7 DTPA/IgG may be superior imaging agents because of reduced accumulation by background organs.  相似文献   
86.
87.
This study examined the mitogenic response to keratinocyte growth factor (KGF) of normal and tumour-derived human oral keratinocytes in which the degree of cellular differentiation was known and in contiguous fibroblast cultures derived from the malignant epithelial cultures. Keratinocytes, but not fibroblasts, were stimulated by KGF. There by demonstrating epithelial target cell specificity of the ligand. KGF-induced stimulation of the tumour-derived keratinocytes cultured in the absence of the 3T3 fibroblast support broadly correlated with the degree of cellular differentiation; well-differentiated keratinocytes were stimulated more by KGF than their less differentiated counterparts. Malignant oral keratinocytes expressed KGF cell surface receptors (KD 451-709 pM; receptors/cell 2306-413645), but KGF receptor mRNA did not correlate with either KGF-induced mitogenesis or the degree of epithelial cell differentiation. When the tumour-derived keratinocytes were cultured in the presence of 3T3 fibroblasts, the mitogenic response to KGF was comparable to normal epithelial cells. The results suggest that KGF-mediated growth stimulation may not be significant in providing a selective advantage for the growth of malignant keratinocytes.  相似文献   
88.
89.
During the past few decades, management of patients with myocardial infarction has dramatically evolved. High-risk patients are now identified by a variety of noninvasive tests, and aggressive use of reperfusion strategies has improved clinical outcomes. Despite the benefits of reperfusion, only a few patients are eligible to receive thrombolytic therapy. Mortality rates among patients excluded from thrombolytic trials (15% to 20%) have been far greater than those eligible for treatment (3% to 10%). Because most deaths occur within the first few days of infarction, interventions designed to reduce mortality should be performed acutely. Immediate catheterization allows identification of high-risk anatomy that may benefit from surgery and allows coronary angioplasty to be performed as a reperfusion strategy (when appropriate). Furthermore, catheterization allows documentation of ejection fraction, vessel patency, number of diseased vessels, and residual stenosis, all of which have been predictive of prognosis. Conversely, frequently repeated noninvasive diagnostic tests are associated with increased cost, are generally performed in low-risk patients, and 60% to 80% of patients with myocardial infarction ultimately require catheterization anyway. It is possible that early catheterization and percutaneous transluminal coronary angioplasty when indicated may effectively risk stratify patients (eliminating the need for noninvasive testing), may reduce morbidity and mortality, and shorten the length of hospital stay.  相似文献   
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