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   4905029篇
  免费   398424篇
  国内免费   16308篇
耳鼻咽喉   70347篇
儿科学   153931篇
妇产科学   128843篇
基础医学   736175篇
口腔科学   138212篇
临床医学   450267篇
内科学   895455篇
皮肤病学   113837篇
神经病学   416381篇
特种医学   195085篇
外国民族医学   1145篇
外科学   740232篇
综合类   143238篇
现状与发展   25篇
一般理论   2886篇
预防医学   418747篇
眼科学   116844篇
药学   347848篇
  26篇
中国医学   12555篇
肿瘤学   237682篇
  2021年   57076篇
  2019年   59613篇
  2018年   75969篇
  2017年   58054篇
  2016年   64798篇
  2015年   77524篇
  2014年   112634篇
  2013年   178549篇
  2012年   139896篇
  2011年   147306篇
  2010年   130470篇
  2009年   131146篇
  2008年   133390篇
  2007年   143432篇
  2006年   150596篇
  2005年   145986篇
  2004年   146503篇
  2003年   136504篇
  2002年   125957篇
  2001年   184601篇
  2000年   182175篇
  1999年   164439篇
  1998年   75765篇
  1997年   70849篇
  1996年   68809篇
  1995年   64726篇
  1994年   58839篇
  1993年   54540篇
  1992年   123835篇
  1991年   119171篇
  1990年   114111篇
  1989年   110458篇
  1988年   102609篇
  1987年   101012篇
  1986年   95713篇
  1985年   93682篇
  1984年   77023篇
  1983年   68046篇
  1982年   52176篇
  1981年   48303篇
  1980年   45451篇
  1979年   68913篇
  1978年   54345篇
  1977年   47378篇
  1976年   44303篇
  1975年   44336篇
  1974年   50789篇
  1973年   48641篇
  1972年   45662篇
  1971年   41970篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Neurological Sciences - Chronic subdural haematoma (CSDH) is one of the most common neurosurgical pathologies. The recurrence of chronic subdural haematomas is an important concern, considering...  相似文献   
972.
ABSTRACT

Purpose

New instrument-based techniques for anterior chamber (AC) cell counting can offer automation and objectivity above clinician assessment. This review aims to identify such instruments and its correlation with clinician estimates.  相似文献   
973.
Rhinovirus (RV) infections are linked to the development and exacerbation of allergic diseases including allergic asthma. IgE, another contributor to atopic disease pathogenesis, has been shown to regulate DC antiviral functions and influence T cell priming by monocytes. We previously demonstrated that IgE-mediated stimulation of monocytes alters multiple cellular functions including cytokine secretion, phagocytosis, and influenza-induced Th1 development. In this study, we investigate the effects of IgE-mediated stimulation on monocyte-driven, RV-induced T cell development utilizing primary human monocyte-T cell co-cultures. We demonstrate that IgE crosslinking of RV-exposed monocytes enhances monocyte-driven Th2 differentiation. This increase in RV-induced Th2 development was regulated by IgE-mediated inhibition of virus-induced type I IFN and induction of IL-10. These findings suggest an additional mechanism by which two clinically significant risk factors for allergic disease exacerbations—IgE-mediated stimulation and rhinovirus infection—may synergistically promote Th2 differentiation and allergic inflammation.  相似文献   
974.
Abstract

This study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos.  相似文献   
975.
976.
977.
978.
979.
980.
Serum lactate is a non-specific marker of tissue hypoperfusion. Elevated serum lactate is used in the differential diagnosis of acute intestinal ischemia. Although this practice is controversial, in the absence of other validated markers lactate is still used because of its high sensitivity.We present the cases of two patients who developed acute mesenteric ischemia as a post-surgical complication. The patients reported moderate abdominal pain —a non-specific symptom in the postoperative context— and tests showed progressively increasing serum lactate levels, which facilitated suspicion and subsequent diagnostic confirmation through an imaging test.These cases highlight the physiopathological importance of lactate elevation in the perioperative context and of performing a differential diagnosis of its possible causes, including mesenteric ischemia. Although the outcome was negative in the first case, early suspicion allowed us to make an effective diagnosis and administer appropriate treatment in the second patient.  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