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   1330827篇
  免费   99096篇
  国内免费   2419篇
耳鼻咽喉   19102篇
儿科学   40182篇
妇产科学   37260篇
基础医学   202048篇
口腔科学   38922篇
临床医学   116176篇
内科学   248395篇
皮肤病学   28095篇
神经病学   102382篇
特种医学   51748篇
外国民族医学   230篇
外科学   205909篇
综合类   32122篇
现状与发展   2篇
一般理论   373篇
预防医学   103141篇
眼科学   31698篇
药学   101706篇
中国医学   2522篇
肿瘤学   70329篇
  2018年   11781篇
  2015年   11753篇
  2014年   16551篇
  2013年   25463篇
  2012年   34368篇
  2011年   36900篇
  2010年   21439篇
  2009年   20152篇
  2008年   35093篇
  2007年   38060篇
  2006年   38112篇
  2005年   37247篇
  2004年   36504篇
  2003年   35137篇
  2002年   34091篇
  2001年   57227篇
  2000年   58698篇
  1999年   49238篇
  1998年   14149篇
  1997年   12742篇
  1996年   12941篇
  1995年   12081篇
  1994年   11526篇
  1992年   40667篇
  1991年   40845篇
  1990年   40517篇
  1989年   39168篇
  1988年   36455篇
  1987年   36030篇
  1986年   34155篇
  1985年   33013篇
  1984年   25171篇
  1983年   21491篇
  1982年   13015篇
  1981年   12016篇
  1980年   11269篇
  1979年   25345篇
  1978年   18355篇
  1977年   15427篇
  1976年   14441篇
  1975年   16028篇
  1974年   19624篇
  1973年   18687篇
  1972年   17969篇
  1971年   16917篇
  1970年   15909篇
  1969年   15380篇
  1968年   14066篇
  1967年   12903篇
  1966年   11790篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.  相似文献   
4.
5.
6.
7.
8.
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   
9.
10.
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