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   5468009篇
  免费   413652篇
  国内免费   16753篇
耳鼻咽喉   78240篇
儿科学   173019篇
妇产科学   145679篇
基础医学   805698篇
口腔科学   155664篇
临床医学   504813篇
内科学   997573篇
皮肤病学   125871篇
神经病学   456552篇
特种医学   213799篇
外国民族医学   1455篇
外科学   815838篇
综合类   153435篇
现状与发展   24篇
一般理论   3038篇
预防医学   459734篇
眼科学   130896篇
药学   393127篇
  28篇
中国医学   14113篇
肿瘤学   269818篇
  2021年   57280篇
  2019年   59715篇
  2018年   77427篇
  2017年   59428篇
  2016年   66256篇
  2015年   78172篇
  2014年   113012篇
  2013年   178900篇
  2012年   156141篇
  2011年   166434篇
  2010年   135264篇
  2009年   134111篇
  2008年   151744篇
  2007年   163603篇
  2006年   170167篇
  2005年   164298篇
  2004年   164622篇
  2003年   154092篇
  2002年   143577篇
  2001年   219545篇
  2000年   217958篇
  1999年   194064篇
  1998年   79248篇
  1997年   73102篇
  1996年   70918篇
  1995年   66579篇
  1994年   60578篇
  1993年   55945篇
  1992年   145350篇
  1991年   139872篇
  1990年   134576篇
  1989年   130631篇
  1988年   120915篇
  1987年   118996篇
  1986年   112574篇
  1985年   109412篇
  1984年   87363篇
  1983年   76678篇
  1982年   55189篇
  1981年   50944篇
  1980年   47675篇
  1979年   78473篇
  1978年   60139篇
  1977年   52365篇
  1976年   49026篇
  1975年   49971篇
  1974年   57577篇
  1973年   55234篇
  1972年   51996篇
  1971年   47950篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
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   
63.
64.
65.
66.
67.
68.
69.
Abstract

Supporting patients in making informed healthcare decisions is a cornerstone of ethical medical practice. Surgeons frequently draw for and show images to patients when consenting them for operations but the value of this practice in informed decision-making is unclear. An audit was conducted in a General Surgery Department. 244 patients completed questionnaires on the value of visual materials when giving consent for surgery. The complexity of the operations was classified into “simple”, “moderate” or “complex”. 100% of patients felt they had given informed consent to surgery. 62% of patients received at least one form of visual material during the consenting process. All patients who received a drawing, and 99% of those provided with other images, valued these resources. Visual materials were considered more useful to patients when giving consent for moderate or complex operations than simple ones. Approximately one third of patients who did not receive visual materials would have appreciated these when making an informed decision. This research highlights the value of surgeons drawing for, and providing other visual resources to, their patients as part of the consent process. There is a role for further research and training materials in drawing skills for surgeons.  相似文献   
70.
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   
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