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   5595篇
  免费   382篇
  国内免费   72篇
耳鼻咽喉   58篇
儿科学   168篇
妇产科学   117篇
基础医学   654篇
口腔科学   204篇
临床医学   469篇
内科学   1359篇
皮肤病学   140篇
神经病学   258篇
特种医学   109篇
外国民族医学   4篇
外科学   756篇
综合类   198篇
一般理论   2篇
预防医学   459篇
眼科学   111篇
药学   588篇
中国医学   70篇
肿瘤学   325篇
  2024年   6篇
  2023年   93篇
  2022年   204篇
  2021年   350篇
  2020年   176篇
  2019年   222篇
  2018年   217篇
  2017年   173篇
  2016年   209篇
  2015年   221篇
  2014年   267篇
  2013年   327篇
  2012年   477篇
  2011年   503篇
  2010年   272篇
  2009年   218篇
  2008年   322篇
  2007年   261篇
  2006年   269篇
  2005年   243篇
  2004年   190篇
  2003年   153篇
  2002年   152篇
  2001年   22篇
  2000年   29篇
  1999年   34篇
  1998年   35篇
  1997年   23篇
  1996年   21篇
  1995年   28篇
  1994年   26篇
  1993年   28篇
  1992年   19篇
  1991年   10篇
  1990年   23篇
  1989年   26篇
  1988年   22篇
  1987年   24篇
  1986年   14篇
  1985年   8篇
  1984年   8篇
  1983年   16篇
  1982年   14篇
  1981年   14篇
  1980年   9篇
  1979年   5篇
  1977年   9篇
  1975年   6篇
  1974年   7篇
  1973年   4篇
排序方式: 共有6049条查询结果,搜索用时 15 毫秒
61.
62.
In this study, the removal of acetic acid by supported liquid membrane (SLM) using hybrid polyethersulfone (PES)–graphene membrane prepared by vapor induced phase separation (VIPS) was investigated. The effects of graphene loading, coagulation bath temperature, air exposure time, and air humidity on the morphology, mechanical strength, porosity, and contact angle of the membrane were analyzed. The performance and stability of the hybrid membrane as a SLM support for acetic acid removal were studied. The best PES–graphene membrane support was produced at a coagulation bath temperature of 50 °C, an air exposure time of 30 s and air humidity of 80%. The fabricated membrane has a symmetrical micropore cellular structure, high porosity and high contact angle. Under specific SLM conditions, almost 95% of acetic acid was successfully removed from 10 g L−1 aqueous acetic acid solution. The hybrid membrane remains stable for more than 116 h without suffering any membrane breakage during the continuous SLM process.

In this study, the removal of acetic acid by supported liquid membrane (SLM) using hybrid polyethersulfone (PES)–graphene membrane prepared by vapor induced phase separation (VIPS) was investigated.  相似文献   
63.
64.
65.
66.
67.
68.
To study the influence of high-lactose probiotic-containing formula on the course of acute diarrhea, an experiment using a randomized controlled clinical trial with patients having acute diarrhea for 3 days was conducted. One hundred patients were allocated into two groups that were comparable for age, sex, and nutritional status. The test group was administered high-lactose Bifidobacterium bifidum-containing formula, while the control group had no high-lactose probiotic until the end of the experiment. The degree of subsequent diarrhea and recovery were monitored in both groups. The results for the test and control groups were analyzed and compared using the chi-square test and Fisher exact test with a significance level (alpha) of 0.05. The study results revealed that there was no significant difference between the test and control groups (p>0.05) as well as at positive clinical test (13%) and positive floating test (65%). However, the patients receiving probiotic-containing formula had significantly less frequency of stools, when compared with the control group (p<0.05).  相似文献   
69.
70.
Aging is an irreversible physiological process characterized by increased risk of diseases, reduced effectiveness of vaccines, and decreased immune responses. One of the most prominent paradigms of aging and age related conditions is the progressive accumulation of un-repaired DNA breaks leading to apoptosis and exhaustion of stem cells. Here we hypothesized that B lymphocytes from old mice have reduced DNA repair mechanisms as a contributing factor for DNA break accumulation. We analyzed class switch recombination (CSR) of naïve B lymphocytes from old and adult mice to delineate the DNA double strand repair mechanisms during aging. In vitro CSR assays and DNA break analysis by labeling phosphorylated histone H2AX showed that old mice had significantly reduced DNA repair efficiency following DNA breaks. Functional efficiency analysis of DNA break repairs using plasmid ligation method showed that B lymphocytes from old mice had poor repair efficiency and increased misrepair of linear plasmid. Diminished DNA repair in old age can contribute to reduced immune cell repertoire and impaired immunity; increased occurrence of cancer; and reduced stem cell reserve.  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