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   49588篇
  免费   5793篇
  国内免费   3320篇
耳鼻咽喉   362篇
儿科学   723篇
妇产科学   325篇
基础医学   4299篇
口腔科学   967篇
临床医学   6434篇
内科学   5615篇
皮肤病学   478篇
神经病学   1845篇
特种医学   1780篇
外国民族医学   23篇
外科学   4434篇
综合类   11785篇
现状与发展   9篇
一般理论   3篇
预防医学   4973篇
眼科学   873篇
药学   5569篇
  87篇
中国医学   4821篇
肿瘤学   3296篇
  2024年   261篇
  2023年   949篇
  2022年   2168篇
  2021年   2766篇
  2020年   2264篇
  2019年   1621篇
  2018年   1617篇
  2017年   1751篇
  2016年   1512篇
  2015年   2400篇
  2014年   2980篇
  2013年   3131篇
  2012年   4278篇
  2011年   4514篇
  2010年   3532篇
  2009年   3165篇
  2008年   3278篇
  2007年   3141篇
  2006年   2837篇
  2005年   2342篇
  2004年   1559篇
  2003年   1367篇
  2002年   1098篇
  2001年   869篇
  2000年   731篇
  1999年   547篇
  1998年   280篇
  1997年   291篇
  1996年   188篇
  1995年   190篇
  1994年   161篇
  1993年   96篇
  1992年   111篇
  1991年   91篇
  1990年   101篇
  1989年   78篇
  1988年   90篇
  1987年   54篇
  1986年   55篇
  1985年   33篇
  1984年   15篇
  1983年   15篇
  1981年   13篇
  1979年   19篇
  1977年   10篇
  1975年   11篇
  1974年   10篇
  1973年   15篇
  1969年   14篇
  1966年   9篇
排序方式: 共有10000条查询结果,搜索用时 110 毫秒
31.
The modification of semiconductor nanostructures with metallic nanocomponents can promote the separation of electron/hole from photoexited semiconductors by forming heterojunctions, thus exhibit enhanced photocatalytic activities and potential applications. In this study, Pt-based NPs, including Pt, PtCu, and PtCuCo are employed as model co-catalysts to comparatively study their capability to enhance the photocatalytic activity of TiO2 nanosheets. It was found that each of Pt, PtCu, and PtCuCo can greatly enhance the photocatalytic activity of TiO2 toward degradation of organic dyes. Using electron spin resonance spectroscopy, we demonstrated that deposition of Pt-based NPs resulted in more production of reactive oxygen species including hydroxyl radicals, superoxide, and singlet oxygen. The enhancing effects of Pt-based NPs on generation of ROS and photocatalytic activity showed same trend: PtCuCo?>?PtCu?>?Pt. The mechanism underlying the enhancement differences in Pt-based NPs may be mainly related to electronic structure change of Pt in alloying with Cu and Co. These results are valuable for designing hybrid nanomaterials with high photocatalytic efficiency for applications in water purification and antibacterial products.  相似文献   
32.
随着对于双心疾病研究的加深,西医疗法的弊端也开始显现。而中医因其理论架构中早就有对于“心主血脉”和“心主神明”的认识,因此在双心疾病的治疗上有着先天的优势。同时近些年中医疗法的结合应用也取得不错的成绩,本文通过对于双心疾病的病例分析,来研讨这种治疗手段的合理性和先进性。  相似文献   
33.
目的对比分析单纯关节镜手术与关节镜手术联合Ilizarov外固定架关节牵张术治疗踝关节创伤性关节炎的临床疗效。 方法纳入2016年10月至2018年4月聊城市中医医院收治的早中期踝关节创伤性关节炎患者30例,排除非创伤性关节炎和终末期踝关节炎。其中接受单纯踝关节镜手术者纳入对照组(n=15),接受关节镜手术联合Ilizarov外固定架关节牵张成形术者纳入研究组(n=15),术后随访6个月,对比分析两组患者的治疗效果:疼痛视觉模拟评分(VAS)、踝关节功能评分(Kofoed评分)以及生活质量的变化。计数资料比较采用卡方或Fisher精确检验,计量资料比较采用独立样本t检验。 结果研究组治疗有效率大于对照组(χ2=7.214,P<0.05),术后疼痛视觉模拟评分明显低于对照组(t =10.342,P<0.05),Kofoed评分高于对照组(t =10.452,P<0.05);研究组生活质量显著高于对照组(P<0.05)。 结论关节镜手术联合关节牵张成形术对早中期踝关节创伤性关节炎较单纯关节镜手术短期效果更好,可成为临床治疗中的一种选择,但远期效果尚需进一步研究。  相似文献   
34.
35.
目的比较内镜手术与显微手术治疗垂体腺瘤的安全性和有效性。方法计算机检索Pubmed、EMbase、CBM、CNKI、万方及VIP等数据库,查找所有比较内镜手术与显微手术治疗垂体瘤的随机对照试验或病例对照研究,检索时限均为建库至2014年5月31日。按纳入排除标准由两人独立进行研究的筛选、资料提取和质量评价后,采用Rev Man5.2软件进行Meta分析。结果共纳入8个研究、712例患者,结果显示,与显微手术相比,内镜手术肿瘤全切率[优势比(OR)=1.23;95%可信区间(CI)(0.62~2.46);P=0.56]、手术时间(P0.05)、术后激素水平改善率[OR=1.21;95%CI(0.58~2.55);P=0.61]、术后脑脊液漏发生率[OR=1.44;95%CI(0.80~2.58);P=0.23]、脑/脑膜炎发生率明显减少[OR=1.15;95%CI(0.38~3.48);P=0.81]、尿崩发生率[OR=1.17;95%CI(0.71~1.94);P=0.53]均无明显改善,而术后鼻出血发生率[OR=0.24;95%CI(0.07~0.78);P=0.02]和术后住院天数明显缩短(P0.05)。结论内镜手术与显微手术相比其术后鼻出血患者较少,术后住院天数短。  相似文献   
36.
Background:Colon cancer is a common malignant tumor of the gastrointestinal tract. Therefore, a clear diagnosis is particularly important for the treatment of colon cancer. Ultrasound and spiral computed tomography (CT) can both be used in the diagnosis, but each has its own advantages and disadvantages, which could cause confusion in clinical choice. The purpose of this study was to systematically evaluate the practicability of spiral CT and ultrasound in the diagnosis of colon cancer.Methods:A systematic search was performed by retrieving on English databases (PubMed, Embase, Web of Science, the Cochrane Library) and Chinese databases (CNKI, Wanfang, Weipu [VIP], CBM). Besides, manually search for Google and Baidu academic of diagnostic experimental study of ultrasound and spiral CT in the diagnosis of Colon Cancer. The retrieval time limit was from the establishment of the database to October 2020. Two researchers independently extracted and evaluated the quality of the data in the included study. A meta-analysis was performed using Meta Disc1.4 and RevMan5.3 software.Results:Sensitivity, specificity, positive Likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were used to determine the diagnostic efficacy of ultrasonography and helical CT in colorectal cancer.Conclusions:This study will compare the practicability of CT and ultrasound in the diagnosis of colon cancer and provide reliable evidence-based basis for clinicians to choose the appropriate or best evidence-based basis.Ethics and dissemination:The private information from individuals will not be published. This systematic review also will not involve endangering participant rights. Ethical approval is not required. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.OSF Registration number:DOI 10.17605/OSF.IO/WAJHQ  相似文献   
37.
~(131)I治疗非Graves’甲亢及非毒性甲状腺肿后数月,少部分患者体内出现促甲状腺激素受体抗体并诱发Graves’病(GD),发病率在0.05%~5%之间。其发病机制假说有通过自身免疫反应介导等。通过监测体内甲状腺自身抗体水平变化、甲状腺显像,可以预测~(131)I治疗后GD的发生。其治疗方法有抗甲状腺药物治疗、再次放射性~(131)I治疗、手术治疗。  相似文献   
38.
There is very little evidence on the value of giving corticoids in cases of seawater drowning induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Therefore, this study aimed to investigate whether dexamethasone treatment can attenuate seawater instillation-induced acute lung injury in rabbits. Seawater (4 ml/kg body weight) was instilled into the lower trachea of ventilated, anesthetized rabbits. Then these rabbits were assigned randomly 20 min later to receive intravenous injection of 1mg/kg body weight of dexamethasone (dissolving in 2 ml of normal saline) or 2 ml of normal saline. All animals demonstrated immediate drops in arterial oxygen tension (PaO2) and the total thoracic compliance, which were significantly improved after 2 h of dexamethasone treatment. Histopathological study also indicated that dexamethasone treatment markedly attenuated lung histopathological changes, alveolar hemorrhage and inflammatory cells infiltration with evidence of decreasing of myeloperoxidase (MPO) activity and tumor necrosis factor-alpha (TNF-alpha) concentration in lung tissue. In addition, dexamethasone treatment reduced extravascular lung water and lung epithelial-endothelial barrier permeability, up-regulated the expression of surfactant protein-A (SP-A) and alpha-epithelial Na+ channel, and increased Na+/K+-adenosine triphosphatase (Na+/K+-ATPase) activity and Na+/K+-ATPase-alpha1 protein abundance. Thus, these data indicate that dexamethasone treatment might be of benefit in patients with seawater aspiration-induced ALI.  相似文献   
39.
INTRODUCTION: The financial responsibility in health sector was decentralizedfrom central and provincial governments to county and township governments. It was argued that a decentralized system without effective transfer payment mechanism has pushed the poverty area to more disadvantaged positions in economic development in general.  相似文献   
40.
抑郁症患者血浆孤啡肽含量研究   总被引:4,自引:0,他引:4  
目的为探讨抑郁症的可能病因,对抑郁症患者血浆孤啡肽(OFQ)含量进行了对照研究。方法抽取29例抑郁症患者和24例正常人的静脉血,用放射免疫(RIA)的方法分别测其血浆中OFQ含量,比较抑郁症患者和正常人血浆OFQ含量有无差异,抑郁症患者OFQ含量与汉密顿抑郁量表(HAMD)评分的相关性,及抑郁症患者血浆OFQ含量的影响因素。结果与正常人比较,抑郁症组OFQ含量明显升高(t=8.70,P<0.0001);OFQ含量与HAMD评分呈正相关(r=0.63,P<0.01);OFQ含量主要与抑郁情绪、夸大、失眠、自卑感、自杀、强迫症状、教育水平、关注身体健康等因素相关,而年龄、性别、职业、病程、曾用药等其他因素与OFQ含量无明显相关。结论通过测量血浆OFQ含量可作为抑郁症诊断的参考指标。  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