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   11806篇
  免费   894篇
  国内免费   41篇
耳鼻咽喉   134篇
儿科学   474篇
妇产科学   334篇
基础医学   1693篇
口腔科学   563篇
临床医学   1297篇
内科学   2461篇
皮肤病学   177篇
神经病学   943篇
特种医学   231篇
外科学   1064篇
综合类   74篇
一般理论   4篇
预防医学   1407篇
眼科学   107篇
药学   950篇
中国医学   34篇
肿瘤学   794篇
  2023年   103篇
  2022年   158篇
  2021年   284篇
  2020年   276篇
  2019年   322篇
  2018年   396篇
  2017年   322篇
  2016年   294篇
  2015年   372篇
  2014年   437篇
  2013年   614篇
  2012年   903篇
  2011年   935篇
  2010年   496篇
  2009年   461篇
  2008年   788篇
  2007年   748篇
  2006年   667篇
  2005年   682篇
  2004年   611篇
  2003年   550篇
  2002年   489篇
  2001年   155篇
  2000年   129篇
  1999年   119篇
  1998年   96篇
  1997年   84篇
  1996年   62篇
  1995年   81篇
  1994年   75篇
  1993年   68篇
  1992年   76篇
  1991年   76篇
  1990年   78篇
  1989年   57篇
  1988年   60篇
  1987年   49篇
  1986年   62篇
  1985年   66篇
  1984年   46篇
  1983年   44篇
  1982年   28篇
  1981年   43篇
  1980年   28篇
  1979年   32篇
  1978年   28篇
  1977年   16篇
  1976年   16篇
  1975年   18篇
  1974年   20篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
3.
4.
5.
Background: Research has demonstrated that problem behavior has been associated with substance use, but knowledge is lacking on such associations in a low-income country like Nepal. Aims: This study aimed to find associations between emotional and behavioral problems and substance use among Nepalese adolescents. Method: A cross-sectional study was conducted at the end of 2011, with participants from three schools in the Province 4 of Nepal. We selected 408 adolescents aged 12 to 18 (mean 15.2 years, 54% boys) at one urban and two rural schools. The data were collected using the Youth Self-Report and Adolescents’ Substance Use Measurement. Results: Higher scores on withdrawn/depressed symptoms, thought problems, attention problems, delinquent or aggressive behavior or internalizing or externalizing problems were associated with the use of tobacco, alcohol or other substances. In the broadband scales, only internalizing problems predicted the use of intoxicants. Higher scores for attention problems predicted the use of tobacco, any intoxicants, and high-risk user. Conclusion: Our findings indicated that problem behavior among Nepalese adolescents was associated with substance use. Future studies should explore the association between problem behavior and substance use, including causal factors, so that risky behavior among Nepalese adolescents can be prevented.  相似文献   
6.
7.
Purpose:This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration.Methods:Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter.Results:There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05.Conclusions:Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.Key words: Bone Regeneration, Platelet-Rich Plasma, Tissue Engineering, Rats  相似文献   
8.
9.
10.
Loss of function variants in NOTCH1 cause left ventricular outflow tract obstructive defects (LVOTO). However, the risk conferred by rare and noncoding variants in NOTCH1 for LVOTO remains largely uncharacterized. In a cohort of 49 families affected by hypoplastic left heart syndrome, a severe form of LVOTO, we discovered predicted loss of function NOTCH1 variants in 6% of individuals. Rare or low-frequency missense variants were found in 16% of families. To make a quantitative estimate of the genetic risk posed by variants in NOTCH1 for LVOTO, we studied associations of 400 coding and noncoding variants in NOTCH1 in 1,085 cases and 332,788 controls from the UK Biobank. Two rare intronic variants in strong linkage disequilibrium displayed significant association with risk for LVOTO amongst European-ancestry individuals. This result was replicated in an independent analysis of 210 cases and 68,762 controls of non-European and mixed ancestry. In conclusion, carrying rare predicted loss of function variants in NOTCH1 confer significant risk for LVOTO. In addition, the two intronic variants seem to be associated with an increased risk for these defects. Our approach demonstrates the utility of population-based data sets in quantifying the specific risk of individual variants for disease-related phenotypes.  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