全文获取类型
收费全文 | 277493篇 |
免费 | 17705篇 |
国内免费 | 8656篇 |
专业分类
耳鼻咽喉 | 2874篇 |
儿科学 | 8775篇 |
妇产科学 | 3167篇 |
基础医学 | 18826篇 |
口腔科学 | 4539篇 |
临床医学 | 31823篇 |
内科学 | 46047篇 |
皮肤病学 | 4031篇 |
神经病学 | 12887篇 |
特种医学 | 12719篇 |
外国民族医学 | 28篇 |
外科学 | 34469篇 |
综合类 | 26836篇 |
现状与发展 | 30篇 |
一般理论 | 3篇 |
预防医学 | 17974篇 |
眼科学 | 4964篇 |
药学 | 51924篇 |
104篇 | |
中国医学 | 7298篇 |
肿瘤学 | 14536篇 |
出版年
2023年 | 2779篇 |
2022年 | 6020篇 |
2021年 | 12070篇 |
2020年 | 7223篇 |
2019年 | 13130篇 |
2018年 | 7803篇 |
2017年 | 7290篇 |
2016年 | 9068篇 |
2015年 | 11892篇 |
2014年 | 21356篇 |
2013年 | 21812篇 |
2012年 | 22559篇 |
2011年 | 19494篇 |
2010年 | 17498篇 |
2009年 | 16689篇 |
2008年 | 15121篇 |
2007年 | 15174篇 |
2006年 | 12944篇 |
2005年 | 9025篇 |
2004年 | 5248篇 |
2003年 | 4646篇 |
2002年 | 3668篇 |
2001年 | 3138篇 |
2000年 | 2676篇 |
1999年 | 1882篇 |
1998年 | 2258篇 |
1997年 | 2079篇 |
1996年 | 1704篇 |
1995年 | 1697篇 |
1994年 | 1591篇 |
1993年 | 1257篇 |
1992年 | 1545篇 |
1991年 | 1347篇 |
1990年 | 1314篇 |
1989年 | 1235篇 |
1988年 | 1165篇 |
1987年 | 1046篇 |
1986年 | 841篇 |
1985年 | 1759篇 |
1984年 | 1874篇 |
1983年 | 1364篇 |
1982年 | 1432篇 |
1981年 | 1397篇 |
1980年 | 1192篇 |
1979年 | 1030篇 |
1978年 | 818篇 |
1977年 | 802篇 |
1976年 | 705篇 |
1975年 | 474篇 |
1974年 | 487篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
目的 基于文本挖掘技术和生物医学数据库对新型冠状病毒肺炎(COVID-19)相关文献进行数据挖掘分析,探究COVID-19及其主要症状发热、咳嗽、呼吸障碍相关基因靶点,筛选潜在有效的化学药和中药。方法 使用GenCLiP 3网站获取COVID-19和其主要症状咳嗽、发热、呼吸障碍共4个关键词的共有靶点,在METASCAPE数据库中对其进行基因本体(GO)和通路富集分析,再利用String数据库和Cytoscape软件构建共有靶点的蛋白质相互作用网络,筛选获得核心基因,运用DGIdb数据库、SymMap数据库针对核心基因进行中西医治疗药物预测。结果 获得COVID-19及其主要症状共有基因靶点28个,其中有IL2、IL1B、CCL2等核心基因16个,使用DGIdb数据库筛选获得与16个关键靶点相互作用的化学药包括沙利度胺、来氟米特、环孢素等28种,中药包括虎杖、黄芪、芦荟等70味。结论 COVID-19及其主要症状的病理机制可能和CD4、KNG1、VEGFA等28个共有基因相关,可能通过介导TNF、IL-17等信号通路参与COVID-19病理过程。潜在有效药物可能通过作用相关靶点通路起到治疗COVID-19的作用。 相似文献
16.
《The Journal of thoracic and cardiovascular surgery》2023,165(1):94-103.e24
ObjectiveNew-onset postoperative atrial fibrillation (POAF) after cardiac surgery is common, with rates up to 60%. POAF has been associated with early and late stroke, but its association with other cardiovascular outcomes is less known. The objective was to perform a meta-analysis of the studies reporting the association of POAF with perioperative and long-term outcomes in patients with cardiac surgery.MethodsWe performed a systematic review and a meta-analysis of studies that presented outcomes for cardiac surgery on the basis of the presence or absence of POAF. MEDLINE, EMBASE, and the Cochrane Library were assessed; 57 studies (246,340 patients) were selected. Perioperative mortality was the primary outcome. Inverse variance method and random model were performed. Leave-one-out analysis, subgroup analyses, and metaregression were conducted.ResultsPOAF was associated with perioperative mortality (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.58-2.33), perioperative stroke (OR, 2.17; 95% CI, 1.90-2.49), perioperative myocardial infarction (OR, 1.28; 95% CI, 1.06-1.54), perioperative acute renal failure (OR, 2.74; 95% CI, 2.42-3.11), hospital (standardized mean difference, 0.80; 95% CI, 0.53-1.07) and intensive care unit stay (standardized mean difference, 0.55; 95% CI, 0.24-0.86), long-term mortality (incidence rate ratio [IRR], 1.54; 95% CI, 1.40-1.69), long-term stroke (IRR, 1.33; 95% CI, 1.21-1.46), and longstanding persistent atrial fibrillation (IRR, 4.73; 95% CI, 3.36-6.66).ConclusionsThe results suggest that POAF after cardiac surgery is associated with an increased occurrence of most short- and long-term cardiovascular adverse events. However, the causality of this association remains to be established. 相似文献
17.
18.
角膜移植为治疗角膜盲的主要手段,而角膜移植排斥则是决定角膜植片存活时间和病人术后视力的关键。角膜得益于其特殊的眼前节“免疫赦免”状态,使得角膜移植能够在众多器官移植中享有极低的排斥率,然而排斥反应发生的风险依然存在。当机体处于遗传物质异常的特殊状态时,宿主将通过宏观调控“免疫赦免”状态对植片的保护作用或受体对移植物排异产生的有害作用,延迟或促进角膜移植排斥反应的发生,进而影响移植物的存活时间和透明度。该文综述与角膜移植排斥相关的多种全身性遗传疾病,总结全身性遗传疾病对角膜移植排斥的影响,浅析其发生的病理生理学机制以及诊疗的特殊性。 相似文献
19.
《Research in social & administrative pharmacy》2022,18(9):3694-3698
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area. 相似文献
20.
《Vaccine》2022,40(7):1001-1009
Vaccination guidelines for dogs and cats indicate that core vaccines (for dogs, rabies, distemper, adenovirus, parvovirus; for cats, feline parvovirus, herpes virus-1, calicivirus) are essential to maintain health, and that non-core vaccines be administered according to a clinician’s assessment of a pet’s risk of exposure and susceptibility to infection. A reliance on individual risk assessment introduces the potential for between-practice inconsistencies in non-core vaccine recommendations. A study was initiated to determine non-core vaccination rates of dogs (Leptospira, Borrelia burgdorferi, Bordetella bronchiseptica, canine influenza virus) and cats (feline leukemia virus) in patients current for core vaccines in veterinary practices across the United States. Transactional data for 5,531,866 dogs (1,670 practices) and 1,914,373 cats (1,661 practices) were retrieved from practice management systems for the period November 1, 2016 through January 1, 2020, deidentified and normalized. Non-core vaccination status was evaluated in 2,798,875 dogs and 788,772 cats that were core-vaccine current. Nationally, median clinic vaccination rates for dogs were highest for leptospirosis (70.5%) and B. bronchiseptica (68.7%), and much lower for canine influenza (4.8%). In Lyme-endemic states, the median clinic borreliosis vaccination rate was 51.8%. Feline leukemia median clinic vaccination rates were low for adult cats (34.6%) and for kittens and 1-year old cats (36.8%). Individual clinic vaccination rates ranged from 0 to 100% for leptospirosis, B. bronchiseptica and feline leukemia, 0–96% for canine influenza, and 0–94% for borreliosis. Wide variation in non-core vaccination rates between clinics in similar geographies indicates that factors other than disease risk are driving the use of non-core vaccines in pet dogs and cats, highlighting a need for veterinary practices to address gaps in patient protection. Failure to implement effective non-core vaccination strategies leaves susceptible dogs and cats unprotected against vaccine-preventable diseases. 相似文献