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   50534篇
  免费   4591篇
  国内免费   1936篇
耳鼻咽喉   157篇
儿科学   2496篇
妇产科学   182篇
基础医学   2694篇
口腔科学   209篇
临床医学   8143篇
内科学   11658篇
皮肤病学   317篇
神经病学   1822篇
特种医学   1287篇
外国民族医学   5篇
外科学   4351篇
综合类   9973篇
现状与发展   13篇
一般理论   1篇
预防医学   2444篇
眼科学   557篇
药学   5123篇
  66篇
中国医学   3084篇
肿瘤学   2479篇
  2024年   128篇
  2023年   1010篇
  2022年   1246篇
  2021年   2892篇
  2020年   2450篇
  2019年   1819篇
  2018年   1659篇
  2017年   1795篇
  2016年   2024篇
  2015年   1928篇
  2014年   3288篇
  2013年   3625篇
  2012年   2963篇
  2011年   3213篇
  2010年   2510篇
  2009年   2304篇
  2008年   2322篇
  2007年   2484篇
  2006年   2239篇
  2005年   2144篇
  2004年   1957篇
  2003年   1874篇
  2002年   1155篇
  2001年   1049篇
  2000年   925篇
  1999年   703篇
  1998年   656篇
  1997年   597篇
  1996年   551篇
  1995年   472篇
  1994年   389篇
  1993年   308篇
  1992年   283篇
  1991年   221篇
  1990年   172篇
  1989年   200篇
  1988年   182篇
  1987年   144篇
  1986年   133篇
  1985年   223篇
  1984年   147篇
  1983年   100篇
  1982年   118篇
  1981年   104篇
  1980年   76篇
  1979年   72篇
  1978年   56篇
  1977年   47篇
  1976年   34篇
  1975年   24篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
992.
《Brain & development》2019,41(10):883-887
BackgroundARX genetic defect is associated with a spectrum of neurodevelopmental disorders that exhibit a high degree of phenotypic heterogeneity.MethodsWe studied a family with a 13-year old Chinese boy and his two elder brothers presented with infantile epileptic-dyskinetic encephalopathy and clarified the unknown genetic etiology of the youngest brother by whole exome sequencing.ResultsThe youngest brother of this family presented with developmental regression, dystonia, epilepsy, microcephaly, visual impairment and oromotor dysfunction. Hyperlactataemia, raised alanine and muscle complex IV deficiency indicated that he had mitochondrial dysfunction. Likely pathogenic hemizygous missense ARX variants (c.989G > A; p.Arg330His) located in conserved nuclear localization sequence was identified. The variant was carried by his asymptomatic mother and not found in his asymptomatic third elder brother. The intractable seizures showed complete but transient responsiveness to pyridoxal phosphate and finally controlled by valproate treatment.ConclusionThis is the first case of ARX-associated encephalopathy showing mitochondrial dysfunction and transient responsiveness to pyridoxal phosphate treatment.  相似文献   
993.
Abstract

This paper provides an overview of more than 22?years of research conducted in the central Javanese province of Yogyakarta, Indonesia, by teams of researchers associated with Gadjah Mada University and Harvard University, led by the authors of this essay. This work is placed in the context of the very limited literature on early psychosis and mental health services in Indonesia. It provides an overview of mental health services in Indonesia and of this team’s research trajectory, then addresses four key domains: the cultural phenomenology of early experiences of psychotic illness; patterns of onset, with a particular focus on extremely rapid onset psychoses; patterns of care-seeking for first episode illness; and mental health services and patterns of utilization. It then discusses the importance of rapid onset psychosis for research on early psychosis, and the question of whether collinearity of rapidity of onset and rapidity of care-seeking raises questions about the long-standing finding that a short duration of untreated psychosis leads to better outcomes. It concludes by discussing difficulties of prioritizing early intervention models in settings with very low mental health resources.  相似文献   
994.
995.
Campylobacter concisus has been isolated from patients with gastroenteritis and inflammatory bowel disease (IBD), as well as healthy subjects. While strain differences may plausibly explain virulence differentials, an alternative hypothesis posits that the pathogenic potential of this species may depend on altered ecosystem conditions in the inflamed gut. One potential difference is oxygen availability, which is frequently increased under conditions of inflammation and is known to regulate bacterial virulence. Hence, we hypothesized that oxygen influences C. concisus physiology. We therefore characterized the effect of microaerophilic or anaerobic environments on C. concisus motility and biofilm formation, two important determinants of host colonization and dissemination. C. concisus isolates (n = 46) sourced from saliva, gut mucosal biopsies and feces of patients with IBD (n = 23), gastroenteritis (n = 8) and healthy subjects (n = 13), were used for this study. Capacity to form biofilms was determined using crystal violet assay, while assessment of dispersion through soft agar permitted motility to be assessed. No association existed between GI disease and either motility or biofilm forming capacity. Oral isolates exhibited significantly greater capacity for biofilm formation compared to fecal isolates (p<0.03), and showed a strong negative correlation between motility and biofilm formation (r = -0.7; p = 0.01). Motility significantly increased when strains were cultured under microaerophilic compared to anaerobic conditions (p<0.001). Increased biofilm formation under microaerophillic conditions was also observed for a subset of isolates. Hence, differences in oxygen availability appear to influence key physiological aspects of the opportunistic gastrointestinal pathogen C. concisus.  相似文献   
996.
There has been increasing evidence that ascending thoracic aortic aneurysms (TAAs) protect against atherosclerosis. However, there have been no studies examining the relationship between ascending TAAs and clinical endpoints of atherosclerosis, such as stroke or peripheral arterial disease. In this study, we aim to characterize the relationship between TAAs and a specific clinical endpoint of atherosclerosis, myocardial infarction (MI). We compared prevalence of coronary artery disease (CAD) and MIs in 487 patients who underwent surgical repair for ascending TAAs to 500 control patients who did not have an ascending TAA. Multivariate binary logistic regression was used to calculate the odds of having MI if a patient had an ascending TAA versus any of several MI risk factors. There was a significantly lower prevalence of CAD and MI in the ascending TAA group than in the control TAA group. The odds of having a MI if a patient had a MI risk factor were all > 1 (more likely to have a MI), with the lowest statistically significant odds ratio being 1.54 (age; p = 0.001) and the highest being 14.9 (family history of MI; p < 0.001). The odds ratio of having a MI if a patient had an ascending TAA, however, was near 0 at 0.05 (p < 0.001). This study provides evidence that ascending TAAs protect against MIs, adding further support to the hypothesis that ascending TAAs protect against atherosclerotic disease.  相似文献   
997.
998.
Platelets play an important role in atherothrombotic disease. The currently available antiplatelet drugs target key steps of platelet activation including thromboxane A2 synthesis, ADP-mediated signaling, and glycoprotein IIb/IIIa-mediated platelet aggregation. The improvement of our understanding on the pharmacokinetic and pharmacodynamic characteristics of these drugs enables the tailoring of the most appropriate anti-thrombotic therapy to the individual patient and risk situation in the daily clinical practice. However, current antiplatelet therapies are associated with increased bleeding risk. Thus, further research on platelet functions may give rise to numerous new antiplatelet agents with high anti-thrombotic efficiency and low adverse hemorrhagic side effects.  相似文献   
999.
Acute coronary syndromes are a major cause of mortality and morbidity. The objective of this evaluation is to review the clinical trials of two new drugs being developed for the treatment of acute coronary syndromes. The first drug is the anticoagulant otamixaban, and the trial compared otamixaban with unfractionated heparin and eptifibatide in acute coronary syndromes. The second drug is the antiplatelet ticagrelor, and the trial compared ticagrelor with clopidogrel in acute coronary syndromes. In the SEPIA-ACS1 TIMI 42 trial, the primary efficacy endpoint occurred in 6.2% of subjects treated with unfractionated heparin and eptifibatide, and to a significantly lesser extent with otamixaban. In the PLATO trial, the primary efficacy endpoint had occurred less in the ticagrelor group (9.8%) than in the clopidogrel group (11.7%) at 12 months. Two new drugs for acute coronary syndromes, otamixaban and ticagrelor, have recently been shown to have benefits in subjects undergoing percutaneous interventions compared to the present standard regimens for this condition.  相似文献   
1000.
Importance of the field: Migraine is an episodic, substantially inherited brain disorder affecting 15% of adults in Western Europe and North America, and is one of the commonest reasons for patients to see their physicians. While the World Health Organization considers that severe migraine can be as disabling as quadriplegia, unfortunately the condition remains undertreated. Until the 1990s, specific migraine therapies were limited to ergot derivatives.

Areas covered in this review: The triptans, serotonin 5-HT1B/1D receptor agonists, revolutionized the acute management of migraine patients. However, although the triptans are generally effective and safe, not all patients can take them and many do not respond especially to oral therapies. Recently, progress has been made on the therapeutic front, particularly with new acute treatments. This review will focus on the therapeutic potential of ADX10059, a metabotropic glutamate receptor 5, negative allosteric modulator (mGluR5 NAM), in migraine. Data from a proof-of-concept study in episodic migraineurs demonstrated a significant improvement following acute treatment. A large European multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study is currently investigating the efficacy, safety and tolerability of the compound for migraine prevention.

What the reader will gain: The reader will have the basic principles of migraine management and the potential for glutamate-targeted approaches.

Take home message: Targeting glutamatergic transmission in migraine may provide a novel preventive therapy that is effective and well-tolerated.  相似文献   
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