全文获取类型
收费全文 | 7409篇 |
免费 | 532篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 206篇 |
妇产科学 | 49篇 |
基础医学 | 819篇 |
口腔科学 | 128篇 |
临床医学 | 954篇 |
内科学 | 1629篇 |
皮肤病学 | 52篇 |
神经病学 | 530篇 |
特种医学 | 360篇 |
外科学 | 552篇 |
综合类 | 737篇 |
现状与发展 | 1篇 |
预防医学 | 1061篇 |
眼科学 | 52篇 |
药学 | 517篇 |
8篇 | |
中国医学 | 274篇 |
肿瘤学 | 121篇 |
出版年
2024年 | 9篇 |
2023年 | 150篇 |
2022年 | 169篇 |
2021年 | 392篇 |
2020年 | 339篇 |
2019年 | 282篇 |
2018年 | 307篇 |
2017年 | 288篇 |
2016年 | 260篇 |
2015年 | 224篇 |
2014年 | 477篇 |
2013年 | 596篇 |
2012年 | 368篇 |
2011年 | 429篇 |
2010年 | 269篇 |
2009年 | 321篇 |
2008年 | 342篇 |
2007年 | 313篇 |
2006年 | 316篇 |
2005年 | 238篇 |
2004年 | 202篇 |
2003年 | 180篇 |
2002年 | 144篇 |
2001年 | 131篇 |
2000年 | 86篇 |
1999年 | 85篇 |
1998年 | 68篇 |
1997年 | 97篇 |
1996年 | 88篇 |
1995年 | 86篇 |
1994年 | 92篇 |
1993年 | 64篇 |
1992年 | 71篇 |
1991年 | 58篇 |
1990年 | 62篇 |
1989年 | 39篇 |
1988年 | 52篇 |
1987年 | 43篇 |
1986年 | 38篇 |
1985年 | 48篇 |
1984年 | 40篇 |
1983年 | 26篇 |
1982年 | 41篇 |
1981年 | 21篇 |
1980年 | 26篇 |
1979年 | 18篇 |
1978年 | 17篇 |
1977年 | 19篇 |
1976年 | 9篇 |
1971年 | 10篇 |
排序方式: 共有8079条查询结果,搜索用时 15 毫秒
1.
《Vaccine》2020,38(45):7118-7128
IntroductionToward the Global Vaccine Action Plan 2020 goal, almost 90% of countries have established a National Immunization Technical Advisory Group (NITAG). However, little is known about NITAG's contributions to governance.MethodsIn 2017–2018, a two-step, qualitative retrospective study was conducted. Jordan (JO), Argentina (AR), and South Africa (SA) were selected owing to government-financed NITAGs from middle-income countries (MICs), geographic diversity, and a vaccine introduction with NITAG support. Country case studies were developed, collecting data through desk review and face-to-face key informant interviews (KIIs) from Ministry of Health (MoH) and NITAG. Case studies were analyzed together, to assess governance applying the European Observatory on Health Systems and Policies framework focusing on transparency, accountability, participation, integrity, and policy capacity (TAPIC).ResultsDocument review and 53 KII (22 AR, 20 SA, 11 JO) showed NITAGs played a pivotal role as advisors promoting a culture of evidence-informed policies. NITAGs strengthened governance, although practices varied among countries. Meetings were conducted behind-closed-doors, participation restricted to members, only in one country agendas, and recommendations were public (AR). To increase participation, policy capacity, and transparency, countries considered adding experts in communications, advocacy, and economics. AR and SA contemplated including community members. NITAGs functioned autonomously from the government, with no established internal or external monitoring or supervision. NITAG meeting minutes allowed the review of integrity, adherence to terms of reference, standard operating procedures, and conflict of interest (CoI). For the most part, NITAGs abided by their mandates. Significant issues were related to the level of MoH support and oversight of CoI declaration and documentation.ConclusionsSystematically implementing governance approaches could improve processes, better tailor policies, and implementation. The long-term survival and resilience of NITAGs in these countries showed they play a significant role in strengthening governance. Lessons learned could be useful to those promoting country-driven evidence-informed decision-making. 相似文献
2.
目的:分析2010年至2018年甲状腺结节相关SCI论文,并建模进行定性与定量分析。方法:利用文献计量学中的引文分析、共被引分析、数据可视化、聚类分析等方法,使用CiteSpace分析工具,分析来源于Web of ScienceTM核心合集数据库中有关论文的出版情况、国家、机构、作者、知识基础与研究热点。结果:到2018年10月31日截止,研究了4 618篇论文。发表论文数:美国在国家/地区中排名第一,延世大学在研究机构中排名第一,Kwak JY在所有作者中排名第一。从2010年开始,每年发表的论文数量都在稳步增长,有相当多的论文发表在如《新英格兰杂志》、《THYROID》、《JAMA》、《CELL》等高影响因子的期刊上。甲状腺结节的SCI论文参考文献聚类为6类,分别是papillary-like nuclear feature、current statu、radiofrequency ablation、ultrasound elastography、goiter area、data system。代表研究前沿的关键词是meta-analysis、recommendation、thyroid carcinoma、shear wave elastography与bethesda system。结论:本文通过对国际上甲状腺结节的研究基础、研究热点的分析,阐述了甲状腺结节的研究趋势,为我国医学工作者的研究提供参考。 相似文献
3.
Tasuku Ogita Rosaly Vallejo Manaois Manabu Wakagi Tomoyuki Oki Yuko Takano Ishikawa 《International journal of food sciences and nutrition》2016,67(4):431-440
Two cultivars of Japanese parsley were harvested in different seasons; their antioxidant capacities were evaluated by oxygen radical absorbance capacity (ORAC) methods, and the contents of hydrophilic and lipophilic antioxidants were compared. Japanese parsley possessed potent antioxidant capacities both in hydrophilic and lipophilic extracts when evaluated by ORAC methods. LC/MS/MS analyses revealed that chlorogenic acid and four kinds of quercetin glycosides were major antioxidants in the hydrophilic extract. Lutein was the main contributor to the antioxidant capacity of the lipophilic extract. Antioxidant capacities of the hydrophilic extracts of both cultivars tended to be higher in winter because of the increase in the contents of chlorogenic acid and quercetin glycosides. An obvious trend in the lipophilic antioxidant capacities or lutein contents was not observed irrespective of the cultivar. 相似文献
4.
5.
Episodic memory is defined as the ability to recall events in a spatiotemporal context. Formation of such memories is critically dependent on the hippocampal formation and its inputs from the entorhinal cortex. To be able to support the formation of episodic memories, entorhinal cortex and hippocampal formation should contain a neuronal code that follows several requirements. First, the code should include information about position of the agent (“where”), sequence of events (“when”), and the content of the experience itself (“what”). Second, the code should arise instantly thereby being able to support memory formation of one‐shot experiences. For successful encoding and to avoid interference between memories during recall, variations in location, time, or in content of experience should result in unique ensemble activity. Finally, the code should capture several different resolutions of experience so that the necessary details relevant for future memory‐based predictions will be stored. We review how neuronal codes in entorhinal cortex and hippocampus follow these requirements and argue that during formation of episodic memories entorhinal cortex provides hippocampus with instant information about ongoing experience. Such information originates from (a) spatially modulated neurons in medial entorhinal cortex, including grid cells, which provide a stable and universal positional metric of the environment; (b) a continuously varying signal in lateral entorhinal cortex providing a code for the temporal progression of events; and (c) entorhinal neurons coding the content of experiences exemplified by object‐coding and odor‐selective neurons. During formation of episodic memories, information from these systems are thought to be encoded as unique sequential ensemble activity in hippocampus, thereby encoding associations between the content of an event and its spatial and temporal contexts. Upon exposure to parts of the encoded stimuli, activity in these ensembles can be reinstated, leading to reactivation of the encoded activity pattern and memory recollection. 相似文献
6.
7.
Anne-Marie Selzler Veronica Moore Razanne Habash Lauren Ellerton Erica Lenton Roger Goldstein 《COPD》2020,17(4):452-461
Abstract The purpose of this study was to investigate the strength of the relationships between self-efficacy and (i) functional exercise capacity and (ii) physical activity in chronic obstructive pulmonary disease (COPD), and whether self-efficacy assessment type (i.e., COPD symptoms, exercise-task, exercise-barrier, general, falls) and physical activity assessment type (i.e., self-report vs. objective) are moderators. A systematic search of COPD and self-efficacy concepts was conducted using eight databases from inception to 23 January 2019. Studies were included if they provided correlation coefficients of the relationship between self-efficacy and functional exercise capacity or physical activity, were conducted in adults diagnosed with COPD, and were published in English-language journals. A total of 14 correlation coefficients were included in the self-efficacy and functional exercise capacity meta-analysis, and 16 in the self-efficacy and physical activity meta-analysis. Data were screened, reviewed, and extracted independently by two reviewers, with discrepancies resolved by a third reviewer. Stronger self-efficacy was associated with better functional exercise capacity (weighted r?=?0.38, 95%CI [0.25, 0.50]), and greater physical activity (weighted r?=?0.25, 95%CI [0.17, 0.34]). Exercise-task self-efficacy had the strongest relationship to functional exercise capacity (weighted r?=?0.64, 95% CI [0.51, 0.73]). For physical activity, the type of self-efficacy most strongly related was inconclusive. In COPD, self-efficacy has a relationship to functional exercise capacity and physical activity, the strength of which is influenced by the choice of self-efficacy measure. An understanding of these relationships will assist clinicians in selecting the self-efficacy measure most closely related to the outcome of interest. 相似文献
8.
9.
目的:探索和发现中药治疗糖尿病足领域的热点话题和研究前沿。方法:检索中国知网已发表的中药治疗糖尿病足文献(日期:自建库至2019年6月3日),运用文献可视化软件(CiteSpaceⅤ)绘制中药治疗糖尿病足的知识图谱,进行文献关键词共现分析及聚类分析。结果:该关键词共现聚类网络由909个节点,1 241条边组成,被分成24个聚类。研究热点是:1)中西医结合疗法治疗糖尿病足;2)中药足浴。研究前沿是:1)穴位注射;2)活血化瘀清热解毒疗法。结论:中药治疗糖尿病足的未来之路是注重中医疗法的基础上进行中西医结合,且需更多高质量的证据支持。 相似文献
10.
An important part of fundamental research in catalysis is based on theoretical and modeling foundations which are closely connected with studies of single-crystalline catalyst surfaces. These so-called model catalysts are often prepared in the form of epitaxial thin films, and characterized using advanced material characterization techniques. This concept provides the fundamental understanding and the knowledge base needed to tailor the design of new heterogeneous catalysts with improved catalytic properties. The present contribution is devoted to development of a model catalyst system of CeO2 (ceria) on the Cu(111) substrate. We propose ways to experimentally characterize and control important parameters of the model catalyst—the coverage of the ceria layer, the influence of the Cu substrate, and the density of surface defects on ceria, particularly the density of step edges and the density and the ordering of the oxygen vacancies. The large spectrum of controlled parameters makes ceria on Cu(111) an interesting alternative to a more common model system ceria on Ru(0001) that has served numerous catalysis studies, mainly as a support for metal clusters. 相似文献