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   3064758篇
  免费   212728篇
  国内免费   8138篇
耳鼻咽喉   40841篇
儿科学   100072篇
妇产科学   82958篇
基础医学   442554篇
口腔科学   81949篇
临床医学   278773篇
内科学   603298篇
皮肤病学   73745篇
神经病学   247938篇
特种医学   116164篇
外国民族医学   848篇
外科学   454719篇
综合类   56399篇
现状与发展   6篇
一般理论   1088篇
预防医学   235973篇
眼科学   67835篇
药学   224507篇
  9篇
中国医学   6414篇
肿瘤学   169534篇
  2021年   24815篇
  2019年   25565篇
  2018年   37748篇
  2017年   28328篇
  2016年   32342篇
  2015年   36316篇
  2014年   48499篇
  2013年   72861篇
  2012年   100747篇
  2011年   106480篇
  2010年   62676篇
  2009年   58443篇
  2008年   98219篇
  2007年   104796篇
  2006年   105237篇
  2005年   101075篇
  2004年   97048篇
  2003年   93433篇
  2002年   89949篇
  2001年   142318篇
  2000年   145626篇
  1999年   122766篇
  1998年   34802篇
  1997年   30833篇
  1996年   31071篇
  1995年   30021篇
  1994年   27508篇
  1993年   25878篇
  1992年   94879篇
  1991年   92382篇
  1990年   89644篇
  1989年   86785篇
  1988年   79582篇
  1987年   77922篇
  1986年   72878篇
  1985年   69692篇
  1984年   51796篇
  1983年   43800篇
  1982年   25559篇
  1979年   45796篇
  1978年   32321篇
  1977年   27271篇
  1976年   25721篇
  1975年   27951篇
  1974年   32697篇
  1973年   31106篇
  1972年   29091篇
  1971年   27126篇
  1970年   25099篇
  1969年   24093篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
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   
103.
104.
105.
106.
107.
108.
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   
109.
110.
Obesity Surgery - Laparoscopic sleeve gastrectomy (LSG) is increasingly playing a key role in obesity management. Such operations, however, carry complications sometimes including leaks. The...  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