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   179598篇
  免费   14779篇
  国内免费   4378篇
耳鼻咽喉   2307篇
儿科学   6280篇
妇产科学   3077篇
基础医学   26447篇
口腔科学   3004篇
临床医学   16000篇
内科学   27911篇
皮肤病学   2748篇
神经病学   10478篇
特种医学   3733篇
外国民族医学   14篇
外科学   15245篇
综合类   21723篇
现状与发展   18篇
一般理论   3篇
预防医学   22549篇
眼科学   1687篇
药学   19530篇
  90篇
中国医学   7203篇
肿瘤学   8708篇
  2023年   2996篇
  2022年   4310篇
  2021年   7630篇
  2020年   7652篇
  2019年   7686篇
  2018年   7460篇
  2017年   6526篇
  2016年   6388篇
  2015年   6911篇
  2014年   11341篇
  2013年   11951篇
  2012年   10704篇
  2011年   12106篇
  2010年   9654篇
  2009年   8229篇
  2008年   7819篇
  2007年   7512篇
  2006年   6738篇
  2005年   5885篇
  2004年   5083篇
  2003年   4490篇
  2002年   3280篇
  2001年   3142篇
  2000年   2715篇
  1999年   2441篇
  1998年   2085篇
  1997年   1938篇
  1996年   1765篇
  1995年   1701篇
  1994年   1502篇
  1993年   1263篇
  1992年   1128篇
  1991年   1037篇
  1990年   897篇
  1989年   790篇
  1988年   685篇
  1987年   588篇
  1985年   1332篇
  1984年   1530篇
  1983年   1081篇
  1982年   1152篇
  1981年   1044篇
  1980年   987篇
  1979年   878篇
  1978年   717篇
  1977年   600篇
  1976年   748篇
  1975年   590篇
  1974年   557篇
  1973年   499篇
排序方式: 共有10000条查询结果,搜索用时 311 毫秒
81.
《Drug discovery today》2022,27(6):1733-1742
Compounds that exhibit assay interference or undesirable mechanisms of bioactivity are routinely encountered in assays at various stages of drug discovery. We observed that assays for the investigation of thiol-reactive and redox-active compounds have not been collected in a comprehensive review. Here, we review these assays and subject them to experimental optimization to improve their reliability. We demonstrate the usefulness of our assay cascade by assaying a library of bioactive compounds, chemical probes, and a set of approved drugs. These high-throughput assays should complement the array of wet-lab and in silico assays during the initial stages of hit discovery campaigns to pursue only hit compounds with tractable mechanisms of action.  相似文献   
82.
ObjectivesTo review the evidence pertaining to the association between cow’s milk protein allergy and recurrent acute otitis media and otitis media with effusion.MethodsThe CENTRAL, Web of Science, EMBASE, MEDLINE, LILACS databases, and gray literature were searched.ResultsFour studies were included, identifying the prevalence rates: 0.2% of delayed speech due to chronic otitis media with effusion in 382 children with cow’s milk protein allergy, 10.7% of cow’s milk protein allergy in 242 children who underwent ENT procedures, 40% of cow’s milk protein allergy in 25 children with recurrent otitis media with effusion and higher tendency to otitis media in children with cow’s milk protein allergy of 186 children (1.5 + 0.6 vs. 0.4 + 0.1; p < 0.1).ConclusionConsidering the characteristics and methodological variations of the identified studies, it is not possible to state that there is reliable evidence of an association between cow’s milk protein allergy and otitis media.  相似文献   
83.
肠易激综合征(IBS)是一种常见的功能性疾病,中医病名为"肠郁"。郭朋教授根据IBS生理、病理特点,以疏肝健脾法调和肝脾,辨证施治,取得良好疗效。文章从病因病机、辨证论治及经典案例介绍等几个方面对郭教授治疗IBS经验进行系统阐述,以期为中医药治疗IBS提供理论和方法学参考。  相似文献   
84.
85.
BackgroundUnequal housing access resulted in more than 150 million homeless people worldwide, with millions more expected to be added every year due to the ongoing climate-related crises. Homeless population has a counterproductive effect on the social, psychological integration efforts by the community and exposure to other severe health-related issues. Geographic Information Systems (GIS) have long been applied in urban planning and policy, housing and homelessness, and health-related research.MethodsWe used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method to systematically review 24 articles collected from multiple databases (n = 10) that focused on health-related issues among homeless people and used geospatial analysis techniques in their research.ResultsOur findings indicated a geographic clustering of case study locations– 26 out of the 31 case study sites are from the USA and Canada. Studies used spatial analysis techniques to identify hotspots, clusters and patterns of patient location and population distribution. Studies also reported relationships among the location of homeless shelters and substance use, discarded needles, different infectious and non-infectious disease clusters.ConclusionMost studies were restricted in analyzing and visualizing the patterns and disease clusters; however, geospatial analyses techniques are useful and offer diverse techniques for a more sophisticated understanding of the spatial characteristics of the health issues among homeless people. Better integration of GIS in health research among the homeless would help formulate sensible policies to counter health inequities among this vulnerable population group.  相似文献   
86.
87.
BackgroundParkinson’s disease (PD) is a chronic and progressive neurodegenerative disease with no cure, presenting a challenging diagnosis and management. However, despite a significant number of criteria and guidelines have been proposed to improve the diagnosis of PD and to determine the PD stage, the gold standard for diagnosis and symptoms monitoring of PD is still mainly based on clinical evaluation, which includes several subjective factors. The use of machine learning (ML) algorithms in spatial-temporal gait parameters is an interesting advance with easy interpretation and objective factors that may assist in PD diagnostic and follow up.Research questionThis article studies ML algorithms for: i) distinguish people with PD vs. matched-healthy individuals; and ii) to discriminate PD stages, based on selected spatial-temporal parameters, including variability and asymmetry.MethodsGait data acquired from 63 people with PD with different levels of PD motor symptoms severity, and 63 matched-control group individuals, during self-selected walking speed, was study in the experiments.ResultsIn the PD diagnosis, a classification accuracy of 84.6 %, with a precision of 0.923 and a recall of 0.800, was achieved by the Naïve Bayes algorithm. We found four significant gait features in PD diagnosis: step length, velocity and width, and step width variability. As to the PD stage identification, the Random Forest outperformed the other studied ML algorithms, by reaching an Area Under the ROC curve of 0.786. We found two relevant gait features in identifying the PD stage: stride width variability and step double support time variability.SignificanceThe results showed that the studied ML algorithms have potential both to PD diagnosis and stage identification by analysing gait parameters.  相似文献   
88.
Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl2-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl2 treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl2, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl2-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca2+-CaMKII-dependent Akt/mTOR pathway.  相似文献   
89.
90.
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