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   4619篇
  免费   479篇
  国内免费   38篇
耳鼻咽喉   15篇
儿科学   234篇
妇产科学   76篇
基础医学   620篇
口腔科学   154篇
临床医学   605篇
内科学   864篇
皮肤病学   50篇
神经病学   297篇
特种医学   400篇
外国民族医学   1篇
外科学   517篇
综合类   116篇
一般理论   5篇
预防医学   489篇
眼科学   37篇
药学   273篇
中国医学   5篇
肿瘤学   378篇
  2021年   53篇
  2019年   51篇
  2018年   63篇
  2017年   53篇
  2016年   49篇
  2015年   70篇
  2014年   86篇
  2013年   159篇
  2012年   155篇
  2011年   182篇
  2010年   119篇
  2009年   99篇
  2008年   193篇
  2007年   170篇
  2006年   156篇
  2005年   136篇
  2004年   178篇
  2003年   165篇
  2002年   166篇
  2001年   167篇
  2000年   130篇
  1999年   141篇
  1998年   101篇
  1997年   121篇
  1996年   119篇
  1995年   86篇
  1994年   73篇
  1993年   79篇
  1992年   118篇
  1991年   90篇
  1990年   97篇
  1989年   117篇
  1988年   102篇
  1987年   104篇
  1986年   96篇
  1985年   112篇
  1984年   61篇
  1983年   55篇
  1982年   38篇
  1980年   42篇
  1979年   69篇
  1978年   38篇
  1977年   36篇
  1974年   43篇
  1973年   47篇
  1972年   49篇
  1971年   45篇
  1970年   36篇
  1969年   47篇
  1968年   39篇
排序方式: 共有5136条查询结果,搜索用时 265 毫秒
1.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
2.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
3.

Purpose

To quantify eating disorder (ED) stability and diagnostic transition among a community-based sample of adolescents and young adult females in the United States.

Methods

Using 11 prospective assessments from 9,031 U.S. females ages 9–15 years at baseline of the Growing Up Today Study, we classified cases of the following EDs involving bingeing and purging: bulimia nervosa (BN), binge ED, purging disorder (PD), and subthreshold variants defined by less frequent (monthly vs. weekly) bingeing and purging behaviors. We measured number of years symptomatic and probability of maintaining symptoms, crossing to another diagnosis, or resolving symptoms across consecutive surveys.

Results

Study lifetime disorder prevalence was 2.1% for BN and roughly 6% each for binge ED and PD. Most cases reported symptoms during only one survey year. Twenty-six percent of cases crossed between diagnoses during follow-up. Among participants meeting full threshold diagnostic criteria, transition from BN was most prevalent, crossing most frequently from BN to PD (12.9% of BN cases). Within each disorder phenotype, 20%–40% of cases moved between subthreshold and full threshold criteria across consecutive surveys.

Conclusions

Diagnostic crossover is not rare among adolescent and young adult females with an ED. Transition patterns from BN to PD add support for considering these classifications in the same diagnostic category of disorders that involve purging. The prevalence of crossover between monthly and weekly symptom frequency suggests that a continuum or staging approach may increase utility of ED classification for prognostic and therapeutic intervention.  相似文献   
4.
5.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
6.
目的 探讨人手术创伤腹膜组织中核转录因子Sp1激活 ,COL1A1和TIMP 1表达变化与腹膜纤维化之间的关系。方法 采用凝胶电泳迁移率改变分析法 (EMSA)检测手术创伤后不同时间的腹膜组织核转录因子Sp1的表达水平 ,WesternBlot检测COL1A1和TIMP 1蛋白表达 ,Masson染色观察腹膜组织中胶原纤维的变化。结果 Sp1在手术创伤后 0 .5h被活化 ,随着手术时间延长Sp1活性逐渐增强 ,至创伤后 4h时达高峰 ,同时创伤腹膜组织中的COL1A1和TIMP 1蛋白表达水平逐渐升高 ,存在差异显著性 (P <0 .0 1)。在手术创伤期内随手术时间的延长腹膜组织中胶原纤维增加。结论 核转录因子Sp1活化导致Ⅰ型胶原合成增加 ,细胞外基质降解减少 ,从而启动腹膜纤维化进程。  相似文献   
7.
8.
9.
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