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   86416篇
  免费   8577篇
  国内免费   176篇
耳鼻咽喉   1208篇
儿科学   2567篇
妇产科学   1902篇
基础医学   12196篇
口腔科学   2108篇
临床医学   10993篇
内科学   15041篇
皮肤病学   1375篇
神经病学   7061篇
特种医学   2943篇
外国民族医学   11篇
外科学   11773篇
综合类   1689篇
一般理论   72篇
预防医学   10249篇
眼科学   1891篇
药学   6947篇
  1篇
中国医学   79篇
肿瘤学   5063篇
  2021年   1147篇
  2020年   787篇
  2019年   1165篇
  2018年   1458篇
  2017年   1058篇
  2016年   1164篇
  2015年   1310篇
  2014年   1757篇
  2013年   2768篇
  2012年   3639篇
  2011年   3960篇
  2010年   2131篇
  2009年   2025篇
  2008年   3406篇
  2007年   3696篇
  2006年   3596篇
  2005年   3670篇
  2004年   3447篇
  2003年   3184篇
  2002年   3140篇
  2001年   2758篇
  2000年   2851篇
  1999年   2552篇
  1998年   1127篇
  1997年   932篇
  1996年   937篇
  1995年   849篇
  1994年   886篇
  1993年   795篇
  1992年   2148篇
  1991年   2083篇
  1990年   1937篇
  1989年   1901篇
  1988年   1800篇
  1987年   1809篇
  1986年   1704篇
  1985年   1700篇
  1984年   1428篇
  1983年   1288篇
  1982年   861篇
  1981年   734篇
  1980年   655篇
  1979年   1232篇
  1978年   899篇
  1977年   785篇
  1976年   741篇
  1975年   733篇
  1974年   874篇
  1973年   766篇
  1972年   755篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
11.
12.
13.

Background

The Lancet Commission on Global Surgery highlighted global surgical need but offered little insight into the specific surgical challenges of children in low-resource settings. Efforts to strengthen the quality of global pediatric surgical care have resulted in a proliferation of partnerships between low-and middle-income countries (LMICs) and high-income countries (HICs). Standardized tools able to reliably measure gaps in delivery and quality of care are important aids for these partnerships. We undertook a systematic review (SR) of capacity assessment tools (CATs) focused on needs assessment in pediatric surgery.

Methods

A comprehensive search strategy of multiple electronic databases was conducted per PRISMA guidelines without linguistic or temporal restrictions. CATs were selected according to pre-defined inclusion criteria. Articles were assessed by two independent reviewers. Methodological quality of studies was appraised using the COSMIN checklist with 4-point scale.

Results

The search strategy generated 16,641 original publications, of which three CATs were deemed eligible. Eligible tools were either excessively detailed or oversimplified. None used weighted scores to identify finer granularity between institutions. No CATs comprehensively included measures of resources, outcomes, accessibility/impact and training.

Discussion

The results of this study identify the need for a CAT capable of objectively measuring key aspects of surgical capacity and performance in a weighted tool designed for pediatric surgical centers in LMICs.

Type of Study

Systematic Review.

Level of Evidence

II.  相似文献   
14.

Background

Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil–lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting.

Methods

We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity.

Results

Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18–1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50–3.72). Postoperative NLR measurements were not of prognostic significance.

Conclusions

Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery.  相似文献   
15.
Ovarian cancer is the fourth most common cause of cancer-related death in women in the developed world, and one of the most heritable cancers. One of the most significant risk factors for epithelial ovarian cancer (EOC) is a family history of breast and/or ovarian cancer. Combined risk factors can be used in models to stratify risk of EOC, and aid in decisions regarding risk-reduction strategies. Germline pathogenic variants in EOC susceptibility genes including those involved in homologous recombination and mismatch repair pathways are present in approximately 22% to 25% of EOC. These genes are associated with an estimated lifetime risk of EOC of 13% to 60% for BRCA1 variants and 10% to 25% for BRCA2 variants, with lower risks associated with remaining genes. Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) thought to explain an additional 6.4% of the familial risk of ovarian cancer, with 34 susceptibility loci identified to date. However, an unknown proportion of the genetic component of EOC risk remains unexplained. This review comprises an overview of individual genes and SNPs suspected to contribute to risk of EOC, and discusses use of a polygenic risk score to predict individual cancer risk more accurately.  相似文献   
16.
17.
18.
19.
20.
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