全文获取类型
收费全文 | 2499383篇 |
免费 | 176962篇 |
国内免费 | 8504篇 |
专业分类
耳鼻咽喉 | 33498篇 |
儿科学 | 80476篇 |
妇产科学 | 67446篇 |
基础医学 | 353884篇 |
口腔科学 | 71653篇 |
临床医学 | 227745篇 |
内科学 | 476353篇 |
皮肤病学 | 56084篇 |
神经病学 | 191987篇 |
特种医学 | 95402篇 |
外国民族医学 | 458篇 |
外科学 | 375107篇 |
综合类 | 64338篇 |
现状与发展 | 11篇 |
一般理论 | 761篇 |
预防医学 | 183850篇 |
眼科学 | 59328篇 |
药学 | 190552篇 |
75篇 | |
中国医学 | 9769篇 |
肿瘤学 | 146072篇 |
出版年
2021年 | 21292篇 |
2019年 | 20767篇 |
2018年 | 29463篇 |
2017年 | 22903篇 |
2016年 | 25246篇 |
2015年 | 29212篇 |
2014年 | 39927篇 |
2013年 | 56838篇 |
2012年 | 78776篇 |
2011年 | 82895篇 |
2010年 | 49718篇 |
2009年 | 45996篇 |
2008年 | 75326篇 |
2007年 | 80118篇 |
2006年 | 80509篇 |
2005年 | 76821篇 |
2004年 | 73120篇 |
2003年 | 69732篇 |
2002年 | 66937篇 |
2001年 | 128620篇 |
2000年 | 131514篇 |
1999年 | 109229篇 |
1998年 | 28800篇 |
1997年 | 25259篇 |
1996年 | 25277篇 |
1995年 | 24109篇 |
1994年 | 21999篇 |
1993年 | 20467篇 |
1992年 | 82120篇 |
1991年 | 79188篇 |
1990年 | 76967篇 |
1989年 | 73840篇 |
1988年 | 67135篇 |
1987年 | 65403篇 |
1986年 | 61810篇 |
1985年 | 58567篇 |
1984年 | 42887篇 |
1983年 | 36498篇 |
1982年 | 20496篇 |
1979年 | 38168篇 |
1978年 | 26249篇 |
1977年 | 22831篇 |
1976年 | 20709篇 |
1975年 | 22525篇 |
1974年 | 26911篇 |
1973年 | 25934篇 |
1972年 | 24219篇 |
1971年 | 22608篇 |
1970年 | 20906篇 |
1969年 | 19775篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
Krishna S. Iyer 《Platelets》2020,31(4):474-482
Abstract Platelets are small, anucleated effector cells that play an important role in linking the hemostatic and inflammatory processes in the body. Platelet function is known to be altered under various inflammatory conditions including aging. A gain in platelet function during aging can increase the risk of thrombotic events, such as stroke and acute myocardial infarction. Anti-platelet therapy is designed to reduce risk of serious cerebrovascular and cardiovascular events, but the adverse consequences of therapy, such as risk for bleeding increases with aging as well. Age-associated comorbidities such as obesity, diabetes, and hyperlipidemia also contribute to increased platelet activity and thus can enhance the risk of thrombosis. Therefore, identification of unique mechanisms of platelet dysfunction in aging and in age-associated comorbidities is warranted to design novel antiplatelet drugs. This review outlines some of the current areas of research on aging-related mechanisms of platelet hyperactivity and addresses the clinical urgency for designing anti-platelet therapies toward novel molecular targets in the aging population. 相似文献
13.
目的通过Meta分析评价安宁疗护对社区临终患者生活质量的影响。方法计算机检索PubMed、CINAHL、ScienceDirect、MEDLINE、Cochrane Library、SAGE数据库、中国知网、维普中文科技期刊数据库、万方数据库和中国生物医学文献数据库中安宁疗护对社区临终患者的随机对照试验,由2名研究人员独立筛选文献并提取资料,对符合质量标准的随机对照试验进行Meta分析。结果共纳入7篇文献,包括1095名社区临终患者。Meta分析结果显示,安宁疗护可以改善社区临终患者的总体生活质量(SMD=0.48,95%CI0.07~0.88,P=0.02)和情绪功能(SMD=1.27,95%CI0.59~1.95,P<0.001),在改善生活质量的躯体功能、角色功能、认知功能和社会功能水平上差异无统计学意义(P>0.05)。结论安宁疗护能改善社区临终患者的总体生活质量和情绪功能,但对生活质量其他功能的改善情况还需要设计更加规范、多中心、大样本的随机对照试验进一步证实。 相似文献
14.
15.
16.
Mohid S Khan Thomas Walter Amy Buchanan-Hughes Emma Worthington Lucie Keeber Marion Feuilly Enrique Grande 《World journal of gastroenterology : WJG》2020,26(30):4537-4556
BACKGROUND Approximately 20% of patients with neuroendocrine tumours(NETs) develop carcinoid syndrome(CS),characterised by flushing and diarrhoea.Somatostatin analogues or telotristat can be used to control symptoms of CS through inhibition of serotonin secretion.Although CS is often the cause of diarrhoea among patients with gastroenteropancreatic NETs(GEP-NETs),other causes to consider include pancreatic enzyme insufficiency(PEI),bile acid malabsorption and small intestinal bacterial overgrowth.If other causes of diarrhoea unrelated to serotonin secretion are mistaken for CS diarrhoea,these treatments may be ineffective against the diarrhoea,risking detrimental effects to patient quality of life.AIM To identify and synthesise qualitative and quantitative evidence relating to the differential diagnosis of diarrhoea in patients with GEP-NETs.METHODS Electronic databases(MEDLINE,Embase and the Cochrane Library) were searched from inception to September 12,2018 using terms for NETs and diarrhoea.Congresses,systematic literature review bibliographies and included articles were also hand-searched.Any study designs and publication types were eligible for inclusion if relevant data on a cause(s) of diarrhoea in patients with GEP-NETs were reported.Studies were screened by two independent reviewers at abstract and full-text stages.Framework synthesis was adapted to synthesise quantitative and qualitative data.The definition of qualitative data was expanded to include all textual data in any section of relevant publications.RESULTS Forty-seven publications(44 studies) were included,comprising a variety of publication types,including observational studies,reviews,guidelines,case reports,interventional studies,and opinion pieces.Most reported on PEI on/after treatment with somatostatin analogs;9.5%-84% of patients with GEP-NETs had experienced steatorrhoea or confirmed PEI.Where reported,14.3%–50.7% of patients received pancreatic enzyme replacement therapy.Other causes of diarrhoea reported in patients with GEP-NETs included bile acid malabsorption(80%),small intestinal bacterial overgrowth(23.6%-62%),colitis(20%) and infection(7.1%).Diagnostic approaches included faecal elastase,breath tests,tauroselcholic(selenium-75) acid(Se HCAT) scan and stool culture,although evidence on the effectiveness or diagnostic accuracy of these approaches was limited.Assessment of patient history or diarrhoea characteristics was also reported as initial approaches for investigation.From the identified evidence,if diarrhoea is assumed to be CS diarrhoea,consequences include uncontrolled diarrhoea,malnutrition,and perceived ineffectiveness of CS treatment.Approaches for facilitating differential diagnosis of diarrhoea include improving patient and clinician awareness of non-CS causes and involvement of a multidisciplinary clinical team,including gastroenterologists.CONCLUSION Diarrhoea in GEP-NETs can be multifactorial with misdiagnosis leading to delayed patient recovery and inefficient resource use.This systematic literature review highlights gaps for further research on prevalence of non-CS diarrhoea and suitability of diagnostic approaches,to determine an effective algorithm for differential diagnosis of GEP-NET diarrhoea. 相似文献
17.
Stepanova E. S. Makarenkova L. M. Chistyakov V. V. Rybakov Yu. L. Gukasov V. M. Fedotcheva T. A. Parshin V. A. Votyakov V. A. Shimanovskii N. L. 《Pharmaceutical Chemistry Journal》2019,52(12):1016-1020
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was... 相似文献
18.
19.
中药生产过程质量控制关键技术研究进展 总被引:10,自引:8,他引:2
中医药发展已上升到国家战略层面,在医药行业贯彻实施"中国制造2025"战略的新形势下,中药生产过程质量控制是中药工业需要加快突破的关键领域之一。对中药生产过程质量控制领域在工艺设计、分析检测、过程建模、制造装备等方面的关键共性问题进行解析,综述了中药生产过程质量控制体系中工艺过程理解、生产过程实时分析方法开发、过程控制策略建立3个方面的研究进展;并结合企业研究实践,介绍了质量源于设计(quality by design,Qb D)、过程分析技术(process analytical technology,PAT)、实验设计(design of experiment,DOE)、多变量统计分析等关键技术在上述3个研究方向中的应用进展,分析了实际工业应用的难点问题并对其应用前景进行展望,旨在为中药企业应用和提升生产过程质量控制技术提供参考。 相似文献
20.