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   1342706篇
  免费   94994篇
  国内免费   2921篇
耳鼻咽喉   19785篇
儿科学   40393篇
妇产科学   38834篇
基础医学   188187篇
口腔科学   40157篇
临床医学   113451篇
内科学   264037篇
皮肤病学   30343篇
神经病学   106944篇
特种医学   53870篇
外国民族医学   435篇
外科学   208941篇
综合类   31139篇
现状与发展   6篇
一般理论   441篇
预防医学   92704篇
眼科学   31456篇
药学   100572篇
  4篇
中国医学   2996篇
肿瘤学   75926篇
  2018年   11940篇
  2015年   12039篇
  2014年   16953篇
  2013年   25570篇
  2012年   33464篇
  2011年   35323篇
  2010年   20969篇
  2009年   20490篇
  2008年   33967篇
  2007年   37054篇
  2006年   37568篇
  2005年   36356篇
  2004年   35419篇
  2003年   34335篇
  2002年   33828篇
  2001年   63727篇
  2000年   65453篇
  1999年   55513篇
  1998年   14709篇
  1997年   13509篇
  1996年   12970篇
  1995年   12267篇
  1994年   11503篇
  1992年   42837篇
  1991年   41338篇
  1990年   40636篇
  1989年   39618篇
  1988年   37024篇
  1987年   36478篇
  1986年   34967篇
  1985年   33158篇
  1984年   24879篇
  1983年   21104篇
  1982年   12688篇
  1981年   11593篇
  1980年   10798篇
  1979年   23955篇
  1978年   17091篇
  1977年   14858篇
  1976年   13406篇
  1975年   15286篇
  1974年   18104篇
  1973年   17578篇
  1972年   16831篇
  1971年   15739篇
  1970年   14928篇
  1969年   14368篇
  1968年   13482篇
  1967年   12027篇
  1966年   11279篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.

Background

Representative surveys collecting weight, height and MUAC are used to estimate the prevalence of acute malnutrition. The results are then used to assess the scale of malnutrition in a population and type of nutritional intervention required. There have been changes in methodology over recent decades; the objective of this study was to determine if these have resulted in higher quality surveys.

Methods

In order to examine the change in reliability of such surveys we have analysed the statistical distributions of the derived anthropometric parameters from 1843 surveys conducted by 19 agencies between 1986 and 2015.

Results

With the introduction of standardised guidelines and software by 2003 and their more general application from 2007 the mean standard deviation, kurtosis and skewness of the parameters used to assess nutritional status have each moved to now approximate the distribution of the WHO standards when the exclusion of outliers from analysis is based upon SMART flagging procedure. Where WHO flags, that only exclude data incompatible with life, are used the quality of anthropometric surveys has improved and the results now approach those seen with SMART flags and the WHO standards distribution. Agencies vary in their uptake and adherence to standard guidelines. Those agencies that fully implement the guidelines achieve the most consistently reliable results.

Conclusions

Standard methods should be universally used to produce reliable data and tests of data quality and SMART type flagging procedures should be applied and reported to ensure that the data are credible and therefore inform appropriate intervention. Use of SMART guidelines has coincided with reliable anthropometric data since 2007.
  相似文献   
72.
73.
74.
75.
76.
77.
Brain imaging is considered one of the most fruitful applications of radioisotope scanning. Rolipram, a selective phospodiesterase‐4 inhibitor, has been labeled using [125I] with chloramine‐T (Ch‐T) as an oxidizing agent. Factors, such as the amount of substrate, pH, the amount of oxidizing agent, temperature, and the reaction time, have been systematically studied to optimize the iodination process. In addition, bio‐distribution studies have indicated that the brain uptake of [125I]iodorolipram is 7.6 ± 0.33 injected dose/g organ at 10 minutes post‐injection, which cleared from the brain with time until it reaches 1.30 ± 0.17% at 1 hour post‐injection. Therefore, iodorolipram could be considered as a potential, new selective radiotracer for brain imaging.  相似文献   
78.
79.
80.
During the past decades, lipid nanocarriers are gaining momentum with their multiple advantages for the management of skin diseases. Lipid nanocarriers enable to target the therapeutic payload to deep skin layers or even to reach the blood circulation making them a promising cutting-edge technology.Lipid nanocarriers refer to a large panel of drug delivery systems. Lipid vesicles are the most conventional, known to be able to carry lipophilic and hydrophilic active agents. A variety of lipid vesicles with high flexibility and deformability could be obtained by adjusting their composition; namely ethosomes, transfersomes and penetration enhancer lipid vesicles which achieve the best results in term of skin permeation. Others are designed with the objective to perform higher encapsulation rate and higher stability, such as solid lipid nanoparticles and nanostructured lipid nanocarriers.In this review, we attempted to give an overview of lipid based nanocarriers developed with the aim to enhance dermal and transdermal drug delivery. A special focus is put on the nanocarrier composition, behavior and interaction mechanisms with the skin. Recent applications of lipid-based nanocarriers for the management of skin diseases and other illnesses are highlighted as well.  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