全文获取类型
收费全文 | 32812篇 |
免费 | 2714篇 |
国内免费 | 848篇 |
专业分类
耳鼻咽喉 | 129篇 |
儿科学 | 538篇 |
妇产科学 | 586篇 |
基础医学 | 5826篇 |
口腔科学 | 555篇 |
临床医学 | 3875篇 |
内科学 | 5324篇 |
皮肤病学 | 520篇 |
神经病学 | 4058篇 |
特种医学 | 963篇 |
外国民族医学 | 13篇 |
外科学 | 1490篇 |
综合类 | 4209篇 |
现状与发展 | 1篇 |
预防医学 | 2670篇 |
眼科学 | 345篇 |
药学 | 1974篇 |
4篇 | |
中国医学 | 651篇 |
肿瘤学 | 2643篇 |
出版年
2024年 | 8篇 |
2023年 | 336篇 |
2022年 | 389篇 |
2021年 | 772篇 |
2020年 | 950篇 |
2019年 | 995篇 |
2018年 | 1012篇 |
2017年 | 1079篇 |
2016年 | 1090篇 |
2015年 | 1139篇 |
2014年 | 1777篇 |
2013年 | 2221篇 |
2012年 | 1734篇 |
2011年 | 2054篇 |
2010年 | 1592篇 |
2009年 | 1718篇 |
2008年 | 1694篇 |
2007年 | 1828篇 |
2006年 | 1627篇 |
2005年 | 1583篇 |
2004年 | 1393篇 |
2003年 | 1339篇 |
2002年 | 1103篇 |
2001年 | 1036篇 |
2000年 | 867篇 |
1999年 | 683篇 |
1998年 | 594篇 |
1997年 | 523篇 |
1996年 | 442篇 |
1995年 | 550篇 |
1994年 | 434篇 |
1993年 | 307篇 |
1992年 | 241篇 |
1991年 | 186篇 |
1990年 | 133篇 |
1989年 | 107篇 |
1988年 | 83篇 |
1987年 | 82篇 |
1986年 | 81篇 |
1985年 | 100篇 |
1984年 | 103篇 |
1983年 | 75篇 |
1982年 | 76篇 |
1981年 | 69篇 |
1980年 | 67篇 |
1979年 | 36篇 |
1978年 | 16篇 |
1977年 | 12篇 |
1976年 | 14篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的 建立一种能够快速鉴定人参和西洋参的双重实时荧光PCR方法。方法 通过对人参属及其近似种基因序列的分析比对,设计特异性的引物探针,建立双重实时荧光PCR检测方法。PCR反应体系为Premix Ex Taq (Probe qPCR) 10 μL,人参上下游引物各0.5 μL,西洋参上下游引物各0.3 μL,人参与西洋参特异性探针各0.4 μL,DNA模板2 μL,灭菌去离子水补至20 μL。反应条件为95℃预变性30 s;然后以95℃变性5 s,60℃退火延伸30 s进行40个循环。应用该方法测试了27份DNA样品,包括7份人参、6份西洋参、4份人参与西洋参混合样、10份其他人参属样品及其他常见中药材样品的DNA,以确定该方法的特异性。将人参与西洋参样品DNA混合后10倍稀释成不同浓度后进行检测,用以确定该方法的灵敏度。结果 人参及西洋参样品均在特定的荧光通道下出现典型的阳性扩增曲线,人参与西洋参混合样品均同时出现两条阳性扩增曲线,其它对照样品及空白对照均没有出现阳性扩增曲线。灵敏度检测结果显示该方法检测人参及西洋参的最低检测限均为2 pg DNA/反应。结论 本实验建立的双重实时荧光PCR方法能够同时快速、准确、灵敏地鉴别出人参和西洋参。 相似文献
3.
4.
5.
《Disability and health journal》2022,15(4):101344
BackgroundThere is increasing research interest regarding physical activity behavior among persons with multiple sclerosis (MS), yet there is little known about physical activity and its correlates in Black persons with MS.ObjectiveThis cross-sectional study assessed associations among social cognitive theory (SCT) variables and device-measured and self-reported physical activity in samples of Black and White persons with MS.MethodsParticipants included 67 Black and 141 White persons with MS who wore an ActiGraph accelerometer on a belt around the waist measuring moderate-to-vigorous physical activity (MVPA) for seven days and completed a battery of questionnaires. Questionnaires included demographic and clinical characteristics, leisure-time exercise, exercise self-efficacy, overcoming barriers self-efficacy, function, social support, exercise outcome expectations, and goal setting and planning.ResultsBlack participants with MS engaged in significantly less MVPA, but not sedentary behavior or light physical activity, than the White participants with MS. Black participants further had significantly lower levels of exercise self-efficacy and outcome expectations than the White sample. All SCT correlates were significantly correlated with self-reported physical activity, but only exercise and barriers self-efficacy, perceived function, and exercise goal setting were associated with device-measured MVPA. The difference in physical activity between Black and White participants with MS was accounted for by differences in exercise self-efficacy and outcome expectations.ConclusionsResearchers should consider developing behavioral interventions that target exercise self-efficacy and outcome expectations as SCT variables for increasing physical activity in Black persons with MS. 相似文献
6.
7.
Paul G. Richardson Fredrik Schjesvold Katja Weisel Philippe Moreau Larry D. Anderson Darrell White Paula Rodriguez-Otero Pieter Sonneveld Monika Engelhardt Matthew Jenner Alessandro Corso Jan Dürig Michel Pavic Morten Salomo Meral Beksac Albert Oriol Jindriska Lindsay Anna Marina Liberati Monica Galli Pawel Robak Alessandra Larocca Munci Yagci Filiz Vural Abraham S. Kanate Ruiyun Jiang Lara Grote Teresa Peluso Meletios Dimopoulos 《European journal of haematology》2022,108(1):73-83
8.
Suicides by pentobarbital overdose have increased since about 2012, which appear to be influenced by technical information on active euthanasia that has spread over the Internet. We encountered a pentobarbital poisoning case of a patient with amyotrophic lateral sclerosis. A caregiver found the patient unconscious immediately after two visitors left the room. The patient was immediately transferred to the emergency hospital but eventually declared dead. A fatal concentration of pentobarbital was detected in peripheral blood samples collected in the emergency hospital and during autopsy (53.8 μg/mL and 29.4 μg/mL, respectively). Because the ratios of pentobarbital concentrations between the gastric contents and peripheral blood were 35 and 29 in the hospital and autopsy samples, respectively, it is likely that pentobarbital was administered via the gastrostomy tube. The patient had contacted the visitors through social media. Although the patient had requested the doctor perform active euthanasia and expressed a desire to end their life on social media, nobody had noticed the plan to commit suicide. 相似文献
9.
Derek K. Chu Romina Brignardello-Petersen Gordon H. Guyatt Cristian Ricci Jon Genuneit 《Pediatric allergy and immunology》2022,33(1):e13609
Network meta-analyses (NMAs) simultaneously estimate the effects of multiple possible treatment options for a given clinical presentation. For allergists to benefit optimally from NMAs, they must understand the process and be able to interpret the results. Through a worked example published in Pediatric Allergy and Immunology, we summarize how to identify credible NMAs and interpret them with a focus on recent innovations in the GRADE approach (Grading of Recommendations Assessment, Development, and Evaluation). NMAs build on traditional systematic reviews and meta-analyses that consider only direct paired comparisons by including indirect evidence, thus allowing the simultaneous assessment of the relative effect of all pairs of competing alternatives. Our framework informs clinicians of how to identify credible NMAs and address the certainty of the evidence. Trustworthy NMAs fill a critical gap in providing key inferences using direct and indirect evidence to inform clinical decision making when faced with more than two competing courses of treatment options. This document will help allergists to identify trustworthy NMAs to enhance patient care. 相似文献
10.