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   958篇
  免费   54篇
  国内免费   20篇
耳鼻咽喉   2篇
儿科学   32篇
妇产科学   13篇
基础医学   78篇
口腔科学   27篇
临床医学   164篇
内科学   221篇
皮肤病学   2篇
神经病学   19篇
特种医学   165篇
外科学   85篇
综合类   34篇
预防医学   99篇
眼科学   9篇
药学   27篇
肿瘤学   55篇
  2023年   6篇
  2022年   5篇
  2021年   17篇
  2019年   8篇
  2018年   7篇
  2017年   6篇
  2016年   11篇
  2015年   7篇
  2014年   24篇
  2013年   35篇
  2012年   22篇
  2011年   27篇
  2010年   28篇
  2009年   48篇
  2008年   20篇
  2007年   31篇
  2006年   20篇
  2005年   26篇
  2004年   17篇
  2003年   22篇
  2002年   19篇
  2001年   23篇
  2000年   25篇
  1999年   19篇
  1998年   48篇
  1997年   50篇
  1996年   44篇
  1995年   42篇
  1994年   26篇
  1993年   26篇
  1992年   14篇
  1991年   10篇
  1990年   17篇
  1989年   29篇
  1988年   32篇
  1987年   18篇
  1986年   11篇
  1985年   19篇
  1984年   19篇
  1983年   13篇
  1982年   22篇
  1981年   23篇
  1980年   22篇
  1979年   7篇
  1978年   14篇
  1977年   13篇
  1976年   7篇
  1970年   4篇
  1969年   4篇
  1945年   5篇
排序方式: 共有1032条查询结果,搜索用时 25 毫秒
21.
22.

Introduction

Numerous strategies are employed routinely in an effort to lower rates of surgical site infections (SSIs). A laminar flow theatre environment is generally used during orthopaedic surgery to reduce rates of SSIs. Its role in vascular surgery, especially when arterial bypass grafts are used, is unknown.

Methods

A retrospective review of a prospectively maintained database was undertaken for all vascular procedures performed by a single consultant over a one-year period. Cases were performed, via random allocation, in either a laminar or non-laminar flow theatre environment. Demographic data, operative data and evidence of postoperative SSIs were noted. A separate subgroup analysis was undertaken for patients requiring an arterial bypass graft. Univariate and multivariate logistical regression was undertaken to identify significant factors associated with SSIs.

Results

Overall, 170 procedures were analysed. Presence of a groin incision, insertion of an arterial graft and a non-laminar flow theatre were shown to be predictive of SSIs in this cohort. In the subgroup receiving arterial grafts, only a non-laminar flow theatre environment was shown to be predictive of an SSI.

Conclusions

This study suggests that laminar flow may reduce incidences of SSI, especially in the subgroup of patients receiving arterial grafts.  相似文献   
23.
24.
25.
26.
Deposition of crystalline triclinic (t) and monoclinic (m) calcium pyrophosphate dihydrate (CPPD) in fibrocartilage and articular cartilage is the hallmark of chondrocalcinosis. Using biologic grade gelatin to model this crystal growth process, t-CPPD, m-CPPD, amorphous calcium pyrophosphate, orthorhombic calcium pyrophosphate tetrahydrate (o-CPPT), and 3 mixed calcium/sodium pyrophosphate salts were grown at physiologic pH. Amorphous and o-CPPT appeared to be kinetic precursor crystals in the formation of t-CPPD and m-CPPD. Optimal concentration ranges for the different crystals were determined.  相似文献   
27.
28.
29.
Rotavirus A (RVA) is the leading cause of acute viral gastroenteritis in children under 5 years of age worldwide. G9P[8] is a common RVA genotype that has been persistently prevalent in Jiangsu, China. To determine the genetic diversity of G9P[8] RVAs, 7 representative G9P[8] strains collected from Suzhou Children’s Hospital between 2010 and 2016 (named JS2010‐JS2016) were analyzed through whole‐genome sequencing. All evaluated strains showed the Wa‐like constellation G9‐P[8]‐I1‐R1‐C1‐M1‐A1‐N1‐T1‐E1‐H1. Furthermore, phylogenetic analysis revealed that the VP7 genes of all strains clustered into lineage G9‐III and G9‐VI. With the exception of strain JS2012 (P[8]‐4), the VP4 sequences of all strains belonged to the P[8]‐3 lineage. Sequencing further revealed that amino acid substitutions were present in the antigenic regions of the VP7 and VP4 genes of all strains. Moreover, there were multiple substitutions in antigenic sites I and II of the nonstructural protein 4 (NSP4) genes, whereas the other NSP genes were relatively conserved. In conclusion, our phylogenetic analysis of these 7 G9P[8] strains suggests that RVA varied across regions and time. Therefore, our findings suggest that continued surveillance is necessary to explore the molecular evolutionary characteristics of RVA for better prevention and treatment of acute viral gastroenteritis.  相似文献   
30.
The ageing ovary appears to be characterized by depletion of primordial follicles. The relationship between infertility and the number of follicles in the ovarian cortex is not known. Moreover, there are no accurate markers or clinical methods to predict the decline in ovarian reserve. This study investigates the correlation between early follicular follicle stimulating hormone, ovarian size and follicular density in 60 infertile women aged 19-45 years (mean = 34.4 +/- 5.5). An ovarian biopsy was taken from each patient while performing diagnostic laparoscopy (n = 28) or laparotomy for tubal surgery or myomectomy (n = 32). The median number of follicles was similar in tubal and unexplained infertility patients (9.5 versus 5.5). Increasing age showed a significant negative correlation with follicular density and ovarian volume (r = -0.46, P = 0.0003;. r = -0.43, P = 0.0016, respectively). In women > or = 35 years of age the ovarian volume showed a strong correlation with follicular density (r = 0.71, P < 0.0001). Our results indicate that infertile women in their late thirties and over have a decreased ovarian reserve which could possibly be predicted by ovarian volume measurement. Ovarian biopsy may have a place as part of infertility evaluation in older women.   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