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   3269283篇
  免费   278397篇
  国内免费   13315篇
耳鼻咽喉   44869篇
儿科学   102359篇
妇产科学   83917篇
基础医学   524767篇
口腔科学   89086篇
临床医学   294035篇
内科学   565834篇
皮肤病学   90420篇
神经病学   278378篇
特种医学   130856篇
外国民族医学   225篇
外科学   510229篇
综合类   99973篇
现状与发展   23篇
一般理论   2187篇
预防医学   267929篇
眼科学   75530篇
药学   231884篇
  22篇
中国医学   9839篇
肿瘤学   158633篇
  2021年   53339篇
  2020年   35089篇
  2019年   57950篇
  2018年   70863篇
  2017年   53706篇
  2016年   59435篇
  2015年   73644篇
  2014年   107912篇
  2013年   173060篇
  2012年   88271篇
  2011年   87474篇
  2010年   115655篇
  2009年   120399篇
  2008年   74323篇
  2007年   76788篇
  2006年   87869篇
  2005年   82875篇
  2004年   84685篇
  2003年   75762篇
  2002年   65459篇
  2001年   107073篇
  2000年   99900篇
  1999年   98840篇
  1998年   65005篇
  1997年   62497篇
  1996年   54680篇
  1995年   55580篇
  1994年   49584篇
  1993年   46329篇
  1992年   67601篇
  1991年   64258篇
  1990年   61240篇
  1989年   60331篇
  1988年   55255篇
  1987年   53816篇
  1986年   51010篇
  1985年   50761篇
  1984年   46350篇
  1983年   42264篇
  1982年   40326篇
  1981年   37933篇
  1980年   35851篇
  1979年   37309篇
  1978年   33024篇
  1977年   30902篇
  1976年   27766篇
  1975年   26719篇
  1974年   26976篇
  1973年   25988篇
  1972年   24479篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
SCN1A is one of the most relevant epilepsy genes. In general, de novo severe mutations, such as truncating mutations, lead to a classic form of Dravet syndrome (DS), while missense mutations are associated with both DS and milder phenotypes within the GEFS+ spectrum, however, these phenotype‐genotype correlations are not entirely consistent. Case report. We report an 18‐year‐old woman with a history of recurrent febrile generalized tonic‐clonic seizures (GTCS) starting at age four months and afebrile asymmetric GTCS and episodes of arrest, suggestive of focal impaired awareness seizures, starting at nine months. Her psychomotor development was normal. Sequencing of SCN1A revealed a heterozygous de novo truncating mutation (c.5734C>T, p.Arg1912X) in exon 26. Conclusion. Truncating mutations in SCN1A may be associated with milder phenotypes within the GEFS+ spectrum. Accordingly, SCN1A gene testing should be performed as part of the assessment for sporadic patients with mild phenotypes that fit within the GEFS+ spectrum, since the finding of a mutation has diagnostic, therapeutic and genetic counselling implications.  相似文献   
992.
Treatment decisions in patients with metastatic bone disease rely on accurate survival estimation. We developed the original PATHFx models using expensive, proprietary software and now seek to provide a more cost-effective solution. Using open-source machine learning software to create PATHFx version 2.0, we asked whether PATHFx 2.0 could be created using open-source methods and externally validated in two unique patient populations. The training set of a well-characterized, database records of 189 patients and the bnlearn package within R Version 3.5.1 (R Foundation for Statistical Computing), was used to establish a series of Bayesian belief network models designed to predict survival at 1, 3, 6, 12, 18, and 24 months. Each was externally validated in both a Scandinavian (n = 815 patients) and a Japanese (n = 261 patients) data set. Brier scores and receiver operating characteristic curves to assessed discriminatory ability. Decision curve analysis (DCA) evaluated whether models should be used clinically. DCA showed that the model should be used clinically at all time points in the Scandinavian data set. For the 1-month time point, DCA of the Japanese data set suggested to expect better outcomes assuming all patients will survive greater than 1 month. Brier scores for each curve demonstrate that the models are accurate at each time point. Statement of Clinical Significance: we successfully transitioned to PATHFx 2.0 using open-source software and externally validated it in two unique patient populations, which can be used as a cost-effective option to guide surgical decisions in patients with metastatic bone disease.  相似文献   
993.
目的:特应性皮炎的发病及治疗存在很大的异质性,在治疗方面特别强调个体化治疗,本文主要总结成年女性特应性皮炎的治疗思路和方法。方法:基于肝脾两脏的生理、病理及成年女性特应性皮炎的临床表现,深入分析其病因病机及治疗方法。结果:女性成年特应性皮炎患者常肝脾同病,肝郁脾虚湿蕴和肝郁脾虚血弱是成年女性特应性皮炎的常见证型,临床可采用疏肝健脾祛湿法和疏肝健脾养血法进行治疗。典型病例中采用肝脾同调法不但可以改善患者的皮疹,也可有效缓解瘙痒和不良情绪。结论:肝脾同调法是治疗成年女性特应性皮炎的有效方法。  相似文献   
994.
In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114–134, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
995.
ObjectiveStimulation of the dorsal spinal roots, or spinal nerve root stimulation (SNRS), is a neuromodulation modality that can target pain within specific dermatomal distributions. The use of paresthesia-free stimulation has been described with conventional dorsal column spinal cord stimulation, although has yet to be described for SNRS. This objective of this study was to investigate the efficacy of paresthesia-free high-frequency (1000–1200 Hz) SNRS in the treatment of intractable, dermatomal neuropathic pain.Materials and MethodsA retrospective chart review was performed on 14 patients implanted with SNRS in varying distributions: Ten patients initially received tonic stimulation and crossed over to a paresthesia-free paradigm and four patients received only paresthesia-free stimulation. The primary outcome was reduction in pain severity (visual analog scale [VAS]), measured at baseline and follow-up to 24 months with paresthesia-free stimulation.ResultsAll 14 patients who received paresthesia-free stimulation had significant improvement in pain severity at a mean follow-up of 1.39 ± 0.15 years (VAS 7.46 at baseline vs. 3.25 at most recent follow-up, p < 0.001). Ten patients were initially treated with tonic stimulation and crossed over to paresthesia-free stimulation after a mean of 61.7 months. Baseline pain in these crossover patients was significantly improved at last follow-up with tonic stimulation (VAS 7.65 at baseline vs. 2.83 at 48 months, p < 0.001), although all patients developed uncomfortable paresthesias. There was no significant difference in pain severity between patients receiving tonic and paresthesia-free stimulation.ConclusionsWe present real-world outcomes of patients with intractable dermatomal neuropathic pain treated with paresthesia-free, high-frequency SNRS. We demonstrate its effectiveness in providing pain reduction at a level comparable to tonic SNRS up to 24 months follow-up, without producing uncomfortable paresthesias.  相似文献   
996.
997.
998.
999.
Phone use is a critical communication event in many people''s lives. Audiologists have aimed to assist individuals with hearing loss and phone usage through the use of technology and counseling. To counsel effectively, all contributions to hearing difficulty on the phone must be considered, including the effects of smartphone cases. The purpose of this study was to evaluate the effects on dB output caused by waterproof smartphone cases that cover the ear-level speaker. One waterproof case was tested with three smartphones, two iPhones, and one Android. A second waterproof case was tested with the two iPhones. Results revealed there was significant attenuation of the audio-signal by both waterproof smartphone cases that was great enough in one case/phone combination to potentially result in a complete lack of intelligibility of the signal.  相似文献   
1000.
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