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   2363520篇
  免费   181772篇
  国内免费   7752篇
耳鼻咽喉   32089篇
儿科学   77828篇
妇产科学   66820篇
基础医学   333580篇
口腔科学   66251篇
临床医学   209228篇
内科学   471044篇
皮肤病学   53753篇
神经病学   190008篇
特种医学   94806篇
外国民族医学   619篇
外科学   366908篇
综合类   52739篇
现状与发展   3篇
一般理论   696篇
预防医学   184247篇
眼科学   52725篇
药学   172445篇
  9篇
中国医学   4284篇
肿瘤学   122962篇
  2018年   23047篇
  2016年   20930篇
  2015年   23686篇
  2014年   33017篇
  2013年   49912篇
  2012年   64159篇
  2011年   68788篇
  2010年   42085篇
  2009年   40419篇
  2008年   65181篇
  2007年   70150篇
  2006年   71573篇
  2005年   69695篇
  2004年   66997篇
  2003年   65160篇
  2002年   62896篇
  2001年   108391篇
  2000年   111571篇
  1999年   94053篇
  1998年   28018篇
  1997年   25126篇
  1996年   25963篇
  1995年   25461篇
  1994年   24001篇
  1993年   22354篇
  1992年   77640篇
  1991年   76073篇
  1990年   74059篇
  1989年   71055篇
  1988年   66241篇
  1987年   64938篇
  1986年   61775篇
  1985年   59282篇
  1984年   44870篇
  1983年   38372篇
  1982年   23678篇
  1981年   21154篇
  1980年   19827篇
  1979年   41581篇
  1978年   29778篇
  1977年   25375篇
  1976年   23669篇
  1975年   25402篇
  1974年   29929篇
  1973年   28721篇
  1972年   26917篇
  1971年   24934篇
  1970年   22979篇
  1969年   21931篇
  1968年   20600篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
13.
14.
Analyzing functional species’ characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2–4 % to pesticides, and for 3–11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches.  相似文献   
15.
16.
17.
18.
19.
The current situation in which the humanities are disparaged affects all university disciplines, including nursing, in whose historical evolution the humanities have always been present in one form or another. Looking beyond this disrepute, this study proposes that nursing renew its attention to classical philosophy. Specifically, it invites a close reading of Xenophon's Anabasis and Plato's Meno, to get three related goals: to show how the use of ancient texts are very valuable tools for the philosophical initiation of nursing students and can help them reflect on their choice of nursing as a practical activity; to reflect on the problem of virtue and the nature of the good life; and to show how the interaction with ancient texts allows students to reflect on questions and issues of life, theirs and others, that are not open to investigation through a purely scientific method. Consequently, both Anabasis and Meno readings strengthen the intellectual relationship between philosophy and nursing, enabling the latter to delve deeper into the key questions of its own thought as a discipline.  相似文献   
20.
Lasers in Medical Science - Studies reported the harmful effects of 2,4-D on body tissues, provoking changes in the anatomy and physiology of the kidneys, liver, and testicles. Thus, the objective...  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