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   5107844篇
  免费   390831篇
  国内免费   15525篇
耳鼻咽喉   71519篇
儿科学   164607篇
妇产科学   136774篇
基础医学   760977篇
口腔科学   144043篇
临床医学   467064篇
内科学   930740篇
皮肤病学   120864篇
神经病学   426196篇
特种医学   200416篇
外国民族医学   1144篇
外科学   764830篇
综合类   144661篇
现状与发展   24篇
一般理论   2896篇
预防医学   423194篇
眼科学   121133篇
药学   366176篇
  26篇
中国医学   13231篇
肿瘤学   253685篇
  2021年   56861篇
  2019年   59241篇
  2018年   76170篇
  2017年   58471篇
  2016年   64939篇
  2015年   77308篇
  2014年   111712篇
  2013年   177436篇
  2012年   143223篇
  2011年   151245篇
  2010年   131725篇
  2009年   131521篇
  2008年   137320篇
  2007年   147190篇
  2006年   154862篇
  2005年   148871篇
  2004年   150161篇
  2003年   139673篇
  2002年   128701篇
  2001年   201759篇
  2000年   199129篇
  1999年   178765篇
  1998年   76272篇
  1997年   70981篇
  1996年   69049篇
  1995年   64486篇
  1994年   58479篇
  1993年   54249篇
  1992年   133684篇
  1991年   128715篇
  1990年   124319篇
  1989年   121026篇
  1988年   111896篇
  1987年   109837篇
  1986年   104127篇
  1985年   101358篇
  1984年   81755篇
  1983年   72047篇
  1982年   53108篇
  1981年   49046篇
  1980年   45897篇
  1979年   72783篇
  1978年   56065篇
  1977年   49203篇
  1976年   45819篇
  1975年   46759篇
  1974年   52820篇
  1973年   50575篇
  1972年   47375篇
  1971年   44096篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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   
62.
63.
64.
65.
66.
67.
68.
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   
69.
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   
70.
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