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   45858篇
  免费   4276篇
  国内免费   1568篇
耳鼻咽喉   104篇
儿科学   618篇
妇产科学   969篇
基础医学   7094篇
口腔科学   1333篇
临床医学   4605篇
内科学   6669篇
皮肤病学   350篇
神经病学   6492篇
特种医学   1060篇
外科学   4830篇
综合类   4491篇
现状与发展   2篇
一般理论   1篇
预防医学   3321篇
眼科学   546篇
药学   6220篇
  16篇
中国医学   1893篇
肿瘤学   1088篇
  2024年   117篇
  2023年   796篇
  2022年   1119篇
  2021年   2241篇
  2020年   2096篇
  2019年   1825篇
  2018年   1754篇
  2017年   1967篇
  2016年   2066篇
  2015年   2007篇
  2014年   3032篇
  2013年   4090篇
  2012年   2526篇
  2011年   2973篇
  2010年   2301篇
  2009年   2447篇
  2008年   2535篇
  2007年   2135篇
  2006年   1950篇
  2005年   1512篇
  2004年   1417篇
  2003年   1223篇
  2002年   947篇
  2001年   823篇
  2000年   689篇
  1999年   573篇
  1998年   556篇
  1997年   480篇
  1996年   430篇
  1995年   298篇
  1994年   281篇
  1993年   232篇
  1992年   253篇
  1991年   222篇
  1990年   222篇
  1989年   209篇
  1988年   160篇
  1987年   131篇
  1986年   125篇
  1985年   178篇
  1984年   154篇
  1983年   91篇
  1982年   98篇
  1981年   85篇
  1980年   74篇
  1979年   69篇
  1978年   62篇
  1977年   38篇
  1976年   38篇
  1973年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
目的 探讨员工援助计划服务对心内科护士职业认同感、职业价值观、职业压力的影响。 方法 选择2018年1-3月我院心内科护理人员58名,为其实施员工援助计划服务,评价实施前后心内科护士的职业认同感、职业价值观、职业压力感知、职业压力反应。 结果 实施后,心内科护士工作压力源各维度评分、压力感知与压力反应各维度得分均较实施前下降(P<0.05);职业价值观各维度及职业认同感各维度评分均较实施前显著提高(P<0.001)。 结论 员工援助计划可提高心内科护士职业认同感、职业价值观,缓解其职业压力感知以及职业压力反应。  相似文献   
53.
创伤后应激障碍(PTSD)是指突发性、威胁性或灾难性生活事件导致个体延迟出现和长期持续存在的精神障碍,其临床表现以再度体验创伤为特征,并伴有情绪的易激惹和回避行为。PTSD的发生不仅伴随着行为学指标异常,机制研究表明还表现出神经生物学指标异常。PTSD的发生机制研究多集中在神经内分泌系统、中枢神经系统和免疫系统等方面,主要表现为应激激素、促炎细胞因子、神经递质、神经保护因子的水平异常。中药因其具有多靶点、多成分和多途径的特点,在治疗PTSD方面表现出了许多优势。当前研究表明,多种中药能够改善PTSD模型中动物行为异常、逆转神经生物学指标。其中很多中药复方已经应用于临床并且具有很好的疗效,因此中药治疗PTSD具有广阔的应用前景。但是,尚未有PTSD的专属治疗药物,且尚未完全厘清PTSD的机制。故本文对当前中药治疗PTSD的研究进行综述,并且从治疗的中药种类、作用机制、动物模型等角度,重点阐述PTSD的发生与治疗进展,以期为PTSD的治疗提供参考。  相似文献   
54.
Inflammation plays a critical role in the development of ventilator-induced lung injury (VILI). Endoplasmic reticulum (ER) stress is associated with a variety of diseases through the modulation of inflammatory responses. However, little is known about how ER stress is implicated in VILI. In this study, murine mechanical ventilation models were constructed. Total protein and inflammatory cytokines were measured in bronchoalveolar lavage fluid (BALF), and lung tissue injury was assessed by histology. Our data revealed that mice subjected to high tidal ventilation (TV) for 4 h showed more severe pulmonary edema and inflammation than those of mice with spontaneous breathing and low TV-treatment. In addition, the high TV-treated animals upregulated the ER stress markers GRP78, CHOP, p-IRE1α, TRAF2, and p-NF-κB expression at both the mRNA and protein levels in lung tissue. Administration of thapsigargin exacerbated the histological changes, inflammation and expression of GRP78 and CHOP after high TV, but treatment with ER stress and IRE1α kinase inhibitors attenuated the pathological damage and downregulated the high expression of GRP78, CHOP, p-IRE1α, TRAF2, and p-NF-κB, suggesting that ER stress is involved in VILI though the IRE1α/TRAF2/NF-κB signaling pathway in mice.  相似文献   
55.
Abstract

Cadmium (Cd) as environmental pollutant can induce severe damage, particularly to the testis. This study investigated the effects of Caffeic acid phenethyl ester (CAPE) on testicular dysfunction induced by Cd. Adult mice were intraperitoneally injected with cadmium chloride (CdCl2) with different doses of CAPE pretreatment. After CdCl2 injection, body/testis weight ratio decreased, Cd levels accumulated and zinc levels decreased in testis. Furthermore, Cd intoxication caused a significant increase of oxidative stress levels, antioxidant enzymes activities, and glutathione levels. Interestingly, significant improvements were observed after the administration of CAPE. Our results demonstrated the protective effect of CAPE, linking Cd testicular dysfunction to oxidative stress.  相似文献   
56.
金银花分子生物学研究进展   总被引:1,自引:0,他引:1  
分子生物学(molecular biology)是从分子水平阐明生命现象和本质的科学,其发展为传统生药学的研究提供了新的生物技术和方法。金银花作为常用大宗药材之一,国内外学者在深入研究传统方法的基础上,采用分子生物学手段对其展开真伪鉴别、品质评价和控制等方面的相关研究,并取得了一定成果。该文主要综述了近年来分子生物学技术方法在金银花鉴别、有效成分生物合成的分子机制以及胁迫条件下次生代谢产物积累的分子机制研究,并针对基于杂交技术的标记(RFLP)、基于PCR的分子标记(RAPD,AFLP,SSR,ISSR)和基于DNA序列分析的SNP及DNA条形码对金银花的多样性识别、诊断、鉴定等方面进行了详细的总结,同时提出可以采用多组学技术,构建系统生物学技术和平台,建立次生代谢产物生物合成的相关模型,从而更好地研究金银花活性成分生物合成的分子机制以及药用植物在环境胁迫下的相关代谢产物的合成和积累等生命活动规律并进行调控,为进一步推动金银花现代化及其他中药资源的开发利用提供支撑与参考。  相似文献   
57.
58.
ObjectivesTo assess the effects of a yoga nidra on life stress and self-esteem in university students.MethodsThis study is a non-equivalent control group pretest-posttest design. Forty university students were selected by convenience sampling, with 20 assigned to a yoga nidra group and 20 to a control group. The yoga group participated in bi-weekly, 1-h sessions of yoga nidra for 8 weeks. Life stress intensity level was measured using a 10 cm Visual Analog Scale. Self-esteem score was measured by Rosenberg's Self-Esteem Scale.ResultsThe yoga nidra group showed significantly decreased life stress intensity levels compared to the control group. The yoga group also showed significantly increased self-esteem scores compared to the control group.ConclusionsThese findings indicate that yoga nidra could alleviate the life stress intensity level and increase the self-esteem in university students.  相似文献   
59.
60.
《Dental materials》2019,35(6):871-882
ObjectiveDevelopment of residual stresses is a potential source of premature fractures in glassy materials, being of special interest in novel lithium silicate glass-ceramics that require a crystallization firing to achieve their final mechanical properties. The aim of this work was to assess the influence of various firing tray systems and the application of different cooling protocols on the development of residual stresses in Suprinity PC crowns. Their effect on the in vitro lifetime of the restorations was also studied.MethodsThirty crowns were milled out of Suprinity PC blocks and crystallized using one of five different commercial firing tray systems (n = 6). Samples in each group were cooled following a fast (FC = 5.5 °C/s), a slow (SC = 0.4 °C/s) or the manufacturer’s reference cooling (REF ). Obtained crowns were sagittally or transversally sectioned and the magnitude and distribution of residual stresses was determined using the light birefringence method. Extra crowns of three of the subgroups (n = 8) were produced and submitted to chewing simulation for 106 cycles or until fracture ensued.ResultsAverage residual stresses ranged between 0 and 1.5 MPa (peaks of 5 MPa). Highest stress magnitudes were observed at the support areas of groups using firing pins, leading to thermal cracks in FC samples and premature failures in the REF subgroup. The use of fibrous pads and firing pastes limited the development of residual stresses, whereas application of SC regimes extended the lifetime of the restorations.SignificanceDevelopment of residual stresses during crystallization firing in lithium silicate glass-ceramics results critical for their mechanical performance and should be therefore avoided by ensuring a homogenous cooling of the structures.  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