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   21771篇
  免费   1715篇
  国内免费   578篇
耳鼻咽喉   196篇
儿科学   339篇
妇产科学   579篇
基础医学   2773篇
口腔科学   562篇
临床医学   2369篇
内科学   4620篇
皮肤病学   272篇
神经病学   1371篇
特种医学   563篇
外国民族医学   3篇
外科学   2952篇
综合类   1465篇
现状与发展   3篇
一般理论   6篇
预防医学   1143篇
眼科学   759篇
药学   1861篇
  6篇
中国医学   576篇
肿瘤学   1646篇
  2023年   226篇
  2022年   228篇
  2021年   726篇
  2020年   510篇
  2019年   540篇
  2018年   645篇
  2017年   562篇
  2016年   562篇
  2015年   727篇
  2014年   920篇
  2013年   1065篇
  2012年   1619篇
  2011年   1700篇
  2010年   1006篇
  2009年   820篇
  2008年   1261篇
  2007年   1270篇
  2006年   1321篇
  2005年   1278篇
  2004年   1066篇
  2003年   919篇
  2002年   895篇
  2001年   550篇
  2000年   545篇
  1999年   499篇
  1998年   213篇
  1997年   211篇
  1996年   158篇
  1995年   135篇
  1994年   121篇
  1993年   92篇
  1992年   216篇
  1991年   195篇
  1990年   170篇
  1989年   158篇
  1988年   121篇
  1987年   123篇
  1986年   99篇
  1985年   70篇
  1984年   56篇
  1983年   46篇
  1982年   57篇
  1981年   52篇
  1980年   46篇
  1979年   41篇
  1978年   36篇
  1977年   21篇
  1975年   23篇
  1973年   17篇
  1971年   14篇
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
1.
2.
3.
4.
Investigative studies of white matter (WM) brain structures using diffusion MRI (dMRI) tractography frequently require manual WM bundle segmentation, often called “virtual dissection.” Human errors and personal decisions make these manual segmentations hard to reproduce, which have not yet been quantified by the dMRI community. It is our opinion that if the field of dMRI tractography wants to be taken seriously as a widespread clinical tool, it is imperative to harmonize WM bundle segmentations and develop protocols aimed to be used in clinical settings. The EADC‐ADNI Harmonized Hippocampal Protocol achieved such standardization through a series of steps that must be reproduced for every WM bundle. This article is an observation of the problematic. A specific bundle segmentation protocol was used in order to provide a real‐life example, but the contribution of this article is to discuss the need for reproducibility and standardized protocol, as for any measurement tool. This study required the participation of 11 experts and 13 nonexperts in neuroanatomy and “virtual dissection” across various laboratories and hospitals. Intra‐rater agreement (Dice score) was approximately 0.77, while inter‐rater was approximately 0.65. The protocol provided to participants was not necessarily optimal, but its design mimics, in essence, what will be required in future protocols. Reporting tractometry results such as average fractional anisotropy, volume or streamline count of a particular bundle without a sufficient reproducibility score could make the analysis and interpretations more difficult. Coordinated efforts by the diffusion MRI tractography community are needed to quantify and account for reproducibility of WM bundle extraction protocols in this era of open and collaborative science.  相似文献   
5.

Background

Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.

Methods

During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.

Results

No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.

Conclusions

The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach.  相似文献   
6.
In HIV/AIDS research, few studies to date have evaluated ways to improve parental HIV disclosure practices using feedback from HIV-negative children who have recently experienced this event. We conducted semi-structured in-depth interviews with 20 children (aged 6–15) who were partially to fully aware of their parents’ HIV status in rural Guangxi, China. Of the 20 children, eight children who were of older age (11.38 years in average) endorsed parental HIV disclosure, five discouraged it and seven expressed uncertainty. Children’s different experiences and attitudes towards disclosure were seen to be associated with their family dynamics (especially the parent–child relationship), social support and care, experiences of stigma and discrimination, psychosocial suffering, comprehension of the disease and the children’s age. Our study contributes to building a child-centered comprehensive understanding for Chinese parental HIV disclosure. It is imperative that counselors and community advocates assess and help parents achieve optimal readiness preceding disclosure of their illness to their HIV-negative children.  相似文献   
7.
8.
9.
G protein-coupled estrogen receptor-1 (GPER), a member of the G protein-coupled receptor (GPCR) superfamily, mediates estrogen-induced proliferation of normal and malignant breast epithelial cells. However, its role in breast cancer stem cells (BCSCs) remains unclear. Here we showed greater expression of GPER in BCSCs than non-BCSCs of three patient-derived xenografts of ER/PR+ breast cancers. GPER silencing reduced stemness features of BCSCs as reflected by reduced mammosphere forming capacity in vitro, and tumor growth in vivo with decreased BCSC populations. Comparative phosphoproteomics revealed greater GPER-mediated PKA/BAD signaling in BCSCs. Activation of GPER by its ligands, including tamoxifen (TMX), induced phosphorylation of PKA and BAD-Ser118 to sustain BCSC characteristics. Transfection with a dominant-negative mutant BAD (Ser118Ala) led to reduced cell survival. Taken together, GPER and its downstream signaling play a key role in maintaining the stemness of BCSCs, suggesting that GPER is a potential therapeutic target for eradicating BCSCs.  相似文献   
10.
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