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   37639篇
  免费   2340篇
  国内免费   1549篇
耳鼻咽喉   332篇
儿科学   884篇
妇产科学   514篇
基础医学   5925篇
口腔科学   874篇
临床医学   3593篇
内科学   5148篇
皮肤病学   1206篇
神经病学   1619篇
特种医学   800篇
外国民族医学   6篇
外科学   1834篇
综合类   6154篇
现状与发展   4篇
预防医学   2559篇
眼科学   404篇
药学   6652篇
  13篇
中国医学   1202篇
肿瘤学   1805篇
  2024年   53篇
  2023年   385篇
  2022年   680篇
  2021年   1163篇
  2020年   967篇
  2019年   910篇
  2018年   887篇
  2017年   968篇
  2016年   937篇
  2015年   1012篇
  2014年   1968篇
  2013年   2018篇
  2012年   2001篇
  2011年   2393篇
  2010年   1986篇
  2009年   1825篇
  2008年   1921篇
  2007年   2071篇
  2006年   1782篇
  2005年   1857篇
  2004年   1524篇
  2003年   1462篇
  2002年   1264篇
  2001年   1127篇
  2000年   1060篇
  1999年   1036篇
  1998年   915篇
  1997年   813篇
  1996年   637篇
  1995年   706篇
  1994年   604篇
  1993年   442篇
  1992年   391篇
  1991年   271篇
  1990年   194篇
  1989年   141篇
  1988年   130篇
  1987年   114篇
  1986年   87篇
  1985年   137篇
  1984年   129篇
  1983年   101篇
  1982年   105篇
  1981年   91篇
  1980年   64篇
  1979年   43篇
  1978年   31篇
  1977年   38篇
  1976年   34篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 354 毫秒
11.
12.
目的针对武汉地区医院信息化系统在新型冠状病毒肺炎(简称新冠肺炎)防疫救治过程中暴露出的问题,提出应对突发公共卫生事件时医院信息化的完善方法。方法充分分析医院信息化系统在新冠肺炎防疫救治中所暴露出的各个医院信息化系统结构不同、各个医院之间无法实施信息共享、门诊病房之间系统相互独立、数据信息更新不及时等九大问题,并提出医院信息化基础布局的建立、区域链及大数据临床中的应用等多项措施。结果医院信息化能力的提高有助于降低医护人员工作强度,提高患者的安全。结论新冠肺炎疫情的发生给我国医院信息化系统带来了严峻的挑战,但同时也给我们带来了更大的机遇。我国在未来针对突发公共卫生事件时,医院信息化将为医护人员、患者提供更有利的支持。  相似文献   
13.
欧洲药品局(EMA)于2018年11月发布了"人用药品辅料右旋糖酐的包装说明书资料",该文件引用大量文献全面评价了右旋糖酐的安全性,特别指出含有右旋糖酐辅料的注射和吸入制剂的疫苗与药品,应在说明书中描述有关其过敏反应信息的新要求。介绍该文件的主要内容,期望对我国这类药品说明书的撰写和监管有所帮助。  相似文献   
14.
Mammary carcinoma (MC) is one of most common malignancy in women, and ring finger protein 2 (RNF2) possesses various roles in vast human tumors. In MC tissues as well as in cell lines RNF2 exhibited high expression, had significant association with tumor size, lymph node status, TNM stage, patients’ poor survival, and promoted cell proliferation, colony formation, cell migration and invasion of MC cell lines which was mediated by downregulation of E-cadherin protein. These data reveal that RNF2 protein plays a vital role in the development of MC and may be a potential therapy target of MC.  相似文献   
15.
曾建国  杨子墨 《中国现代中药》2021,23(12):2031-2036
湖南省历经8年聚力打造“湘九味”中药材品牌,已逐渐形成品牌品种引领的产业链发展模式。为达成湖南省中药材产业链千亿发展目标,梳理了“湘九味”品牌培育历程,厘清并阐释了相关概念,分析了产业发展现状及问题,研判了大健康应用背景下未来的中药材产业的发展趋势,并提出相关发展建议。  相似文献   
16.
《Vaccine》2019,37(31):4382-4391
Cancer-associated fibroblasts (CAFs), major components of the tumor microenvironment (TME), promote tumor growth and metastasis and inhibit the anti-tumor immune response. We previously constructed a DNA vaccine expressing human FAPα, which is highly expressed by CAFs, to target these cells in the TME, and observed limited anti-tumor effects in the 4T1 breast cancer model. When the treatment time was delayed until tumor nodes formed, the anti-tumor effect of the vaccine completely disappeared. In this study, to improve the safety and efficacy, we constructed a new FAPα-targeted vaccine containing only the extracellular domain of human FAPα with a tissue plasminogen activator signal sequence for enhanced antigen secretion and immunogenicity. The number of CAFs was more effectively reduced by CD8+ T cells induced by the new vaccine. This resulted in decreases in CCL2 and CXCL12 expression, leading to a significant decrease in the ratio of myeloid-derived suppressor cells in the TME. Moreover, when mice were treated after the establishment of tumors, the vaccine could still delay tumor growth. To facilitate the future application of the vaccine in clinical trials, we further optimized the gene codons and reduced the homology between the vaccine and the original sequence, which may be convenient for evaluating the vaccine distribution in the human body. These results indicated that the new FAPα-targeted vaccine expressing an optimized secreted human FAPα induced enhanced anti-tumor activity by reducing the number of FAPα+ CAFs and enhancing the recruitment of effector T cells in the 4T1 tumor model mice.  相似文献   
17.
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.  相似文献   
18.
Parabens are antimicrobial additives found in a wide array of consumer products. However, the halogenated compounds formed from parabens during wastewater disinfection are a potential environmental concern. In order to identify these transformation products and investigate their mechanism of formation, a synthetic route to ethyl parabens labeled with the stable isotope carbon-13 at specific positions within the benzene ring was developed. This efficient two-step procedure starts from commercially available 13C-labeled phenols and involves (1) initial acylation of the phenol via a Houben–Hoesch reaction with trichloroacetonitrile followed by (2) a modified haloform reaction of the resulting trichloromethyl ketone to afford the corresponding 13C-labeled ethyl parabens in 65%–80% overall yield. The scope of the modified haloform reaction was also investigated, allowing for the synthesis of other parabens derived from primary or secondary alcohols, including 13C- and deuterium-labeled esters. In addition, 4-hydroxybenzoic acid can be formed directly from the common trichloromethyl ketone intermediate upon treatment with lithium hydroxide. This protocol complements existing methods for preparing 13C-labeled paraben derivatives and offers the specific advantages of exhibiting complete regioselectivity in the Houben–Hoesch reaction (to form the para-disubstituted product) and avoiding the need for protecting groups in the modified haloform reaction that forms the paraben esters.  相似文献   
19.
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the “anti-biotic era”. Although, we have expeditiously developed our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts required for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins.In this review article, we provide an overview of the established diagnostic techniques and therapeutics for keratitis caused by various bacteria. We extensively report the recent in-roads through novel tools for accurately diagnosing mono- and poly-bacterial corneal infections. Furthermore, we outline the recent progress by our groups and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discuss in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.  相似文献   
20.
目的分析托珠单抗的安全性风险,为临床合理用药提供参考。方法对世界卫生组织药品不良反应监测数据库、我国药品不良反应监测数据库、国内文献数据库中的不良反应报告情况及国外药监机构风险控制措施等相关资料进行整理与分析。结果应重视托珠单抗临床使用中可能发生的肝功能异常、皮肤损害、过敏反应、胃肠道损害、感染、血液系统损害等不良反应。结论托珠单抗临床使用中,应加强对严重感染及肝功能损害等严重不良反应的安全性监测,促进药品的临床合理使用。  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