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   2660792篇
  免费   184850篇
  国内免费   7568篇
耳鼻咽喉   34859篇
儿科学   87799篇
妇产科学   72729篇
基础医学   372178篇
口腔科学   70109篇
临床医学   239168篇
内科学   530576篇
皮肤病学   62819篇
神经病学   220689篇
特种医学   103215篇
外国民族医学   736篇
外科学   398786篇
综合类   50981篇
现状与发展   5篇
一般理论   968篇
预防医学   202649篇
眼科学   57438篇
药学   191813篇
  8篇
中国医学   5336篇
肿瘤学   150349篇
  2021年   19995篇
  2019年   20627篇
  2018年   37471篇
  2017年   29155篇
  2016年   34174篇
  2015年   29813篇
  2014年   40665篇
  2013年   60616篇
  2012年   82557篇
  2011年   91996篇
  2010年   57143篇
  2009年   53501篇
  2008年   86684篇
  2007年   93208篇
  2006年   85774篇
  2005年   83409篇
  2004年   80748篇
  2003年   78872篇
  2002年   75213篇
  2001年   128667篇
  2000年   131736篇
  1999年   110668篇
  1998年   31407篇
  1997年   28127篇
  1996年   28338篇
  1995年   27518篇
  1994年   25221篇
  1993年   23541篇
  1992年   85284篇
  1991年   81715篇
  1990年   78919篇
  1989年   76166篇
  1988年   69582篇
  1987年   68099篇
  1986年   63638篇
  1985年   60626篇
  1984年   45009篇
  1983年   38009篇
  1982年   22545篇
  1981年   20009篇
  1979年   39061篇
  1978年   27500篇
  1977年   23272篇
  1976年   21557篇
  1975年   22826篇
  1974年   26820篇
  1973年   25386篇
  1972年   23757篇
  1971年   21961篇
  1970年   20216篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
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   
14.
15.
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   
16.
17.
18.
19.
20.
Interstitial cystitis/bladder pain syndrome (IC/BPS) and vulvodynia are chronic pain syndromes that appear to be intertwined from the perspectives of embryology, pathology and epidemiology. These associations may account for similar responses to various therapies.  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