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   211487篇
  免费   19240篇
  国内免费   4350篇
耳鼻咽喉   3296篇
儿科学   4205篇
妇产科学   3679篇
基础医学   16827篇
口腔科学   7350篇
临床医学   20275篇
内科学   20262篇
皮肤病学   2520篇
神经病学   10692篇
特种医学   5969篇
外国民族医学   15篇
外科学   20771篇
综合类   33488篇
现状与发展   10篇
一般理论   26篇
预防医学   27853篇
眼科学   2015篇
药学   20451篇
  343篇
中国医学   25736篇
肿瘤学   9294篇
  2023年   4118篇
  2022年   6387篇
  2021年   10087篇
  2020年   10362篇
  2019年   11670篇
  2018年   10344篇
  2017年   8902篇
  2016年   7959篇
  2015年   7420篇
  2014年   14604篇
  2013年   14967篇
  2012年   12901篇
  2011年   13841篇
  2010年   11136篇
  2009年   9703篇
  2008年   9002篇
  2007年   9068篇
  2006年   7738篇
  2005年   6527篇
  2004年   5419篇
  2003年   4822篇
  2002年   3730篇
  2001年   3077篇
  2000年   2725篇
  1999年   2207篇
  1998年   1634篇
  1997年   1474篇
  1996年   1181篇
  1995年   1236篇
  1994年   1110篇
  1993年   983篇
  1992年   900篇
  1991年   825篇
  1990年   720篇
  1989年   695篇
  1988年   644篇
  1987年   576篇
  1986年   530篇
  1985年   1789篇
  1984年   2059篇
  1983年   1290篇
  1982年   1711篇
  1981年   1182篇
  1980年   1010篇
  1979年   904篇
  1978年   738篇
  1977年   552篇
  1976年   693篇
  1975年   477篇
  1974年   404篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
《Vaccine》2022,40(16):2370-2378
Porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae (M. hyopneumoniae, Mhp) are two of the most common pathogens involved in the porcine respiratory disease complex (PRDC) resulting in significant economic losses worldwide. Vaccination is the most effective approach to disease prevention. Since PRRSV and Mhp co-infections are very common, an efficient dual vaccine against these pathogens is required for the global swine industry. Compared with traditional vaccines, multi-epitope vaccines have several advantages, they are comparatively easy to produce and construct, are chemically stable, and do not have an infectious potential. In this study, to develop a safe and effective vaccine, B cell and T cell epitopes of PRRSV-GP5, PRRSV-M, Mhp-P46, and Mhp-P65 protein had been screened to construct a recombinant epitope protein rEP-PM that has good hydrophilicity, strong antigenicity, and high surface accessibility, and each epitope is independent and complete. After immunization in mice, rEP-PM could induce the production of high levels of antibodies, and it had good immunoreactivity with anti-rEP-PM, anti-PRRSV, and anti-Mhp antibodies. The anti-rEP-PM antibody specifically recognizes proteins from PRRSV and Mhp. Moreover, rEP-PM induced a Th1-dominant cellular immune response in mice. Our results showed that the rEP-PM protein could be a potential candidate for the development of a safe and effective multi-epitope peptide combined vaccine to control PRRSV and Mhp infections.  相似文献   
32.
《Vaccine》2022,40(33):4748-4763
This work identifies the innovations that made it possible for the Bio-Manguinhos/Fiocruz Immunobiological Technology Institute to engage in the entire production of the Oxford/AstraZeneca vaccine (ChAdOx1 nCov-19) in Brazil, just 1.8 years after the COVID-19 pandemic was declared. The results were summarized in a case-based innovation model composed of 11 workstreams, 32 stages, 22 gates, 11 innovations, and 38 events. In terms of research contributions, three were found: (i) the identification of firm and government-level innovations allowing the substantial reduction in the COVID-19 vaccine time-to-market in Brazil; (ii) the presentation of empirical evidence supporting the new Outbreak Paradigm for vaccine research, development, and production; and (iii) the proposition of a conceptual model for describing innovations through the vaccine value chain in pandemic contexts, particularly when technology transfer is involved.  相似文献   
33.
34.
35.
BackgroundIn order to avoid excessive treatment of thyroid nodules in the clinic, it is necessary to find a simple and practical analysis method to comprehensively and accurately reflect benign or malignant thyroid nodules. This study aimed to construct and validate a comprehensive and reliable network-based predictive model using a variety of imaging and laboratory criteria for thyroid nodules to stratify the risk of malignancy prior to surgery.MethodsWe retrospectively analyzed data from patients who underwent surgical treatment for thyroid nodules at the Thyroid and Breast Diagnosis and Treatment Center of Weifang Hospital of Traditional Chinese Medicine between January 2018 and December 2020. Binary logical regression analysis was performed to predict whether nodules were malignant or benign. The developmental dataset included 457 patients (January 2018–December 2020). The validation set included separate data points (n = 225, January 2018–December 2020).ResultsIn this study, criteria that showed significant predictive value for malignant nodules included TI-RADS: 4b (p = 0.065); Bethesda IV, Bethesda V, Bethesda VI (P < 0.0001); BRAFV600E mutation (P < 0.0001); Calcitonin>5 pg/ml (p = 0.0037); and FNA-Tg>30 ng/ml (p = 0.0003). A 10-grade risk scoring system was developed. The risk of malignancy risk ranged from 2.06% to 100% and was positively associated with increasing risk grade. The areas under the receiver-operating characteristic curve of the development and validation sets were 0.972 and 0.946, respectively.ConclusionA simple, comprehensive and reliable web-based predictive model was designed using a variety of imaging and laboratory criteria to stratify thyroid nodules by probability of malignancy.  相似文献   
36.
PurposeThe variation in the immune response to Bartonella spp. infection in humans remains unclear. The present study compares the expression of selected interleukins, cytokines and cathelicidin (LL-37) in rheumatology clinic patients suffering from musculoskeletal symptoms with healthy blood donors. The patients had previously been tested for the presence of Bartonella henselae antibodies.MethodsGene expression of LL-37, interleukin (IL)-2, IL-4, IL-6, IL-12, interferon-(IFN)-γ, and tumor necrosis factor (TNF-α)-α was determined in blood samples using quantitative Polymerase Chain Reaction (qPCR). Statistical analysis was prepared with STATISTICA.ResultsStatistically significant differences in the mRNA levels of the tested cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-12; p<0.0001) were observed between the healthy controls and patients; however, no difference was observed for LL37 mRNA (p ?= ?0.1974). No significant differences in mRNA expression were observed between IgG in anti-Bartonella seropositive and seronegative individuals (p>0.05). The only significant differences between the Bartonella spp. DNA positive and negative patients, indicated by PCR, were observed for TNF-α and IL-12 mRNA (p ?= ?0.0045 and p ?= ?0.0255, respectively).ConclusionA broadly similar immune response to the tested cytokines was observed among the participants irrespective of anti-Bartonella spp. IgG seropositivity. However, the Bartonella DNA-positive participants demonstrated significantly lower expression of IL-12 and TNF-α mRNA; this may indicate that these bacteria have a suppressive influence on the immune system.  相似文献   
37.
38.
ObjectivesSeveral implementation strategies can reduce potentially inappropriate medication (PIM) prescribing. Although use of PIMs has declined in recent years, it remains prevalent. Various strategies exist to improve the appropriateness of medication use. However, little is known about the processes of these different implementation strategies. This scoping review aims to investigate how the process evaluation of implementation strategies for reducing PIM prescribing in the older population has been studied.MethodsWe searched for process evaluations of implementation strategies for reducing PIM prescribing in PUBMED, SCOPUS and Web of Science published between January 2000 and November 2019 in English. We applied the following inclusion criteria: patients aged ≥65 years, validated PIM criteria, and implementation process evaluated. The review focuses on decision support for health care professionals. We described the findings of the process evaluations, and compared the authors’ concepts of process evaluation of the included publications to those of Proctor et al.( 2010).ResultOf 9131 publications screened, 29 met our inclusion criteria. Different process evaluation conceptualizations were identified. Most process evaluations took place in the initial stages of the process (acceptability, adoption, appropriateness, and feasibility) and sustainability and implementation costs were seldom evaluated. None of the included publications evaluated fidelity.Multifaceted interventions were the most studied implementation strategies. Medication review was more common in acceptability evaluations, multidisciplinary interventions in adoption evaluations, and computerized systems and educational interventions in feasibility evaluations. Process evaluations were studied from the health care professionals’ viewpoint in most of the included publications, but the management viewpoint was missing.DiscussionThe conceptualization of process evaluation in the field of PIM prescribing is indeterminate. There is also a current gap in the knowledge of sustainability and implementation costs. Clarifying the conceptualization of implementation process evaluation is essential in order to effectively translate research knowledge into practice.  相似文献   
39.
林兰教授对柴胡芍药枳实甘草汤有独特的理论见解。柴胡芍药枳实甘草汤证的病机,在经为邪郁少阳、气机壅滞,主气郁;在腑为经隧挛急、胆气不降。柴胡芍药枳实甘草汤和解少阳,理气开滞,舒挛止痛,为临床舒畅气血、治疗气郁之名方,临证可用于甲状腺疾病、肝胆疾病、乳腺疾病、妇科疾病及多种疑难杂症。  相似文献   
40.
【目的】 在“中国科技期刊卓越行动计划”实施三周年之际,有必要对我国科技期刊2035年迈入“世界第一方阵”目标的具体任务进行重新审视和预判,以进一步明确发展方向,动态调整推进思路。【方法】 采用国内外科技期刊、科技论文、科技期刊评价成果的系统性发展数据对科技期刊“世界第一方阵” 国家(或地区)在高水平科技期刊数量与质量层面的入围标准进行界定,在深入总结现有基础和优势的同时,对我国科技期刊综合实力与“世界第一方阵”国家(或地区)的现实差距进行逐一梳理和剖析,并对实现目标的可行性和推进思路进行研判和设计。【结果】 必须继续加强高水平英文科技期刊创办和培育力度、持续加大优秀中文科技期刊的建设强度、快速推进国内外科技期刊论文等质同效评价制度的建设与引导,并积极探索建立科学家和科研机构办好一流科技期刊的责任制度和贡献激励机制、创新发展编辑人才队伍培养与激励管理思路、深入实践灵活多样的期刊出版市场资本运作模式、稳步推进期刊出版市场机制和管理制度改革,为我国科技期刊事业的高质量发展提速增效。【结论】 虽然当前阶段目标任务艰巨,但迈入“世界第一方阵”未来可期。  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