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   5010557篇
  免费   396833篇
  国内免费   16022篇
耳鼻咽喉   71615篇
儿科学   158508篇
妇产科学   133788篇
基础医学   747473篇
口腔科学   143356篇
临床医学   455858篇
内科学   912840篇
皮肤病学   116903篇
神经病学   422196篇
特种医学   199403篇
外国民族医学   1270篇
外科学   754638篇
综合类   147613篇
现状与发展   23篇
一般理论   2887篇
预防医学   422881篇
眼科学   119926篇
药学   357842篇
  24篇
中国医学   12831篇
肿瘤学   241537篇
  2021年   56413篇
  2019年   59035篇
  2018年   75166篇
  2017年   57506篇
  2016年   64175篇
  2015年   76825篇
  2014年   111734篇
  2013年   177236篇
  2012年   137705篇
  2011年   144456篇
  2010年   129146篇
  2009年   130178篇
  2008年   131477篇
  2007年   140489篇
  2006年   148789篇
  2005年   143388篇
  2004年   144394篇
  2003年   134278篇
  2002年   124764篇
  2001年   190687篇
  2000年   188771篇
  1999年   170755篇
  1998年   75991篇
  1997年   71125篇
  1996年   69006篇
  1995年   64794篇
  1994年   58881篇
  1993年   54628篇
  1992年   129668篇
  1991年   124673篇
  1990年   119733篇
  1989年   116406篇
  1988年   108253篇
  1987年   106620篇
  1986年   101402篇
  1985年   98986篇
  1984年   80832篇
  1983年   71373篇
  1982年   53424篇
  1981年   49331篇
  1980年   46404篇
  1979年   73401篇
  1978年   56995篇
  1977年   49703篇
  1976年   46463篇
  1975年   46664篇
  1974年   54032篇
  1973年   51901篇
  1972年   48610篇
  1971年   44985篇
排序方式: 共有10000条查询结果,搜索用时 0 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