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   71493篇
  免费   6252篇
  国内免费   1940篇
耳鼻咽喉   609篇
儿科学   1010篇
妇产科学   1042篇
基础医学   9714篇
口腔科学   946篇
临床医学   6459篇
内科学   9568篇
皮肤病学   700篇
神经病学   1880篇
特种医学   3206篇
外科学   7381篇
综合类   9120篇
一般理论   2篇
预防医学   4004篇
眼科学   449篇
药学   5557篇
  22篇
中国医学   1645篇
肿瘤学   16371篇
  2024年   111篇
  2023年   982篇
  2022年   2186篇
  2021年   2838篇
  2020年   2292篇
  2019年   2516篇
  2018年   2664篇
  2017年   2575篇
  2016年   2470篇
  2015年   2671篇
  2014年   4934篇
  2013年   4613篇
  2012年   4152篇
  2011年   4783篇
  2010年   3599篇
  2009年   3811篇
  2008年   4116篇
  2007年   3839篇
  2006年   3372篇
  2005年   2858篇
  2004年   2418篇
  2003年   2098篇
  2002年   1572篇
  2001年   1476篇
  2000年   1341篇
  1999年   1141篇
  1998年   902篇
  1997年   808篇
  1996年   717篇
  1995年   709篇
  1994年   633篇
  1993年   482篇
  1992年   413篇
  1991年   327篇
  1990年   300篇
  1989年   298篇
  1988年   262篇
  1987年   219篇
  1986年   162篇
  1985年   257篇
  1984年   284篇
  1983年   184篇
  1982年   242篇
  1981年   194篇
  1980年   190篇
  1979年   142篇
  1978年   122篇
  1977年   79篇
  1976年   73篇
  1974年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
细胞内钙信号的变化调节血管平滑肌细胞增殖   总被引:4,自引:0,他引:4  
目的探讨细胞内钙信号的变化对大鼠血管平滑肌细胞(VSMC)增殖作用的影响及其对细胞内信号转导机制的变化。方法以培养的大鼠VSMC为模型,用雷尼丁(RY)剌激VSMC内贮Ca2 释放入胞浆,用3H亮氨酸及3H胸腺嘧啶掺入量作为反应VSMC增殖的指标,加入不同的细胞内信号转导阻断剂,观察对RY效应的影响。结果与对照组相比,RY浓度依赖性地促进细胞内游离钙浓度的增高,差异显著(P<0.05或0.01)。RY剌激组蛋白核酸合成速率明显增高,与对照组相比差异显著(P<0.01);尼卡地平(Nicardipine),蛋白激酶C抑制剂(H7),钙调素激酶(CaMPK)抑制剂(W7)和丝裂素活化蛋白激酶(MAPK)抑制剂(PD98059)能明显抑制RY介导的VSMC蛋白核酸合成速率增高,与RY剌激组相比差异显著(P<0.01)。结论细胞内钙信号的变化明显促进VSMC增殖,但其效应可能通过Ca2 、PKC、MAPK来介导。钙离子拮抗剂可抑制血管平滑肌细胞增殖。  相似文献   
42.
程光存  严中亚 《中华实验外科杂志》2004,21(9):1091-1092,i003
目的 比较静态和动态旋转系统中构建组织工程化血管模型中血管内皮细胞分泌功能。方法新型可降解材料聚羟基丁酸酯(PHB),用胶原包埋,形成多孔状PHB 胶原管形支架。分离传代、分化人脐静脉内皮细胞,接种于PHB管型支架内腔面,分别在静态、动态旋转系统中培养14 d后,测定血管内皮细胞分泌一氧化氮(NO)、前列环素(PGI2)水平。结果 在动态旋转系统构建组织工程化血管模型中血管内皮细胞分泌NO、PGI2水平显著高于静态系统,在11 d NO分别为(120.52±3.83)μmmol/L、(80.98±5.98)μmmol/L,PGI2分另9为(20.48±1.52)μg/L,(16.59±1.29)μg/L,与静态系统相比,差异有显著性(P<0.05)。结论胶原包埋PHB支架有利于细胞的黏附和生长,可作为组织工程化血管的支架材料。在动态旋转系统构建组织工程化血管模型中血管内皮细胞,具有与正常血管类似的"生理功能"。  相似文献   
43.
目的用药物敏感试验预测肺癌合并恶性胸腔积液癌细胞对顺铂联合其他药物的敏感度,观察其在指导此类患者的顺铂联合其他化疗药物胸腔内化疗的价值。方法将44例胸腔积液癌细胞阳性肺癌患者随机分为两组:药物敏感试验组(20例,有2例因体外药物敏感试验失败而被排除)和对照组(22例)。药物敏感试验组患者用三磷酸腺苷-肿瘤细胞药物敏感试验(ATP-TCA)法分别检测胸腔积液癌细胞对顺铂加香菇多糖、顺铂加甘露聚糖肽、顺铂加A群链球菌制剂、顺铂加干扰素、顺铂加金黄色葡萄球菌滤液制剂、顺铂加卡介苗多糖核酸、顺铂加红色诺卡菌细胞壁骨架、顺铂加白细胞介素-2的敏感度,并选择抑瘤率最高的联合化疗药物对患者进行胸腔内化疗,观察治疗后胸腔积液完全缓解率及胸腔积液癌细胞转阴率,并与对照组比较。结果药物敏感试验组患者对各联合化疗药物敏感的例数为:顺铂加香菇多糖14例、顺铂加甘露聚糖肽18例、顺铂加A群链球菌制剂17例、顺铂加干扰素10例、顺铂加金黄色葡萄球菌滤液制剂16例、顺铂加卡介苗多糖核酸15例、顺铂加红色诺卡菌细胞壁骨架17例、顺铂加白细胞介素-216例。药物敏感试验组完全缓解率为65.0%,对照组为27.3%(P〈0.05)。药物敏感试验组胸腔积液癌细胞转阴率为80.0%,对照组为45.5%(P〈0.05)。结论用药物敏感试验指导肺癌合并恶性胸腔积液的胸腔内个体化化疗可提高完全缓解率和胸腔积液癌细胞转阴率,该方法具有临床实用价值。  相似文献   
44.
This study investigated the use of attentional control strategies in the self-management of pain using daily process design methodology. Twenty six cancer patients with pain completed diaries 3 times daily for 10 days. Diaries incorporated measures of pain intensity, affect, coping, coping efficacy, and the novelty and predictability of pain, and participants completed a cross-sectional measure of catastrophizing. At the across-person level, focusing on pain was associated with increased negative affect, and the use of pain focusing strategies was positively correlated with experiencing pain that was novel in its location or quality. Distractions that were interesting, important and pleasant were positively correlated with positive affect, perceptions of control over pain and ability to decrease pain. Over-prediction of pain was positively correlated with catastrophizing, and negatively correlated with perceptions of control over and ability to decrease pain. The within-person analysis (ARIMA modelling) showed that catastrophizing moderated the effects of pain focusing strategies, novel pain and over-predictions of pain. Meta-analysis of the ARIMA models revealed that the within-person effects of using attentional strategies did not generalize across the sample. These findings indicated that the effects of distraction strategies are influenced by their motivational-affective significance rather than the frequency with which they are used, and provided further evidence that the threat value of pain influences the way in which people cope with their pain. Theoretical and clinical implications are discussed.  相似文献   
45.
46.
ABO血型不合的异基因造血干细胞移植--2例报告附文献复习   总被引:2,自引:1,他引:1  
探讨ABO血型不合的异基因造血干细胞移植 (Allo -HSCT)的造血问题。方法 :对 2例患者分别进行异基因外周血造血干细胞移植 (Allo -PBSCT)及脐血造血干细胞移植 (CBSCT) ,用血细胞分离机或 6 %羟乙基淀粉去除移植物中的红细胞 ,定期检测受者血型 ,根据情况输注血细胞。结果 :2例患者全部获得造血重建 ,未出现溶血反应。结论 :ABO血型不合可以进行Allo -HSCT ,去除供者移植物中的红细胞能有效地防止急性溶血反应的发生 ,定期检测受者血型 ,及时调整输血方案有重要的临床意义。  相似文献   
47.
It has earlier been proposed by the author that the aetiology of schizophrenic symptomatology may be due to the presence of abnormally connected interhemispheric fibres which link specialised functions in the brains of schizophrenics that are not connected in normal subjects, and that the neuroleptic drugs may produce their action through a local anaesthetic-like effect in suppression of conduction in these fibres. This line of thought has been extended here to consider the possible mechanism of action of the neuroleptic drugs in more detail, as well as that of the tricyclic antidepressant drugs which are derivatives of the phenothiazine group. Pharmacological similarities with the local anaesthetics both structurally and functionally have been considered, as well as the effects that these drug groups may have in common with the lithium salts. It has been suggested that these drugs all produce their primary effect on cell membranes, though not necessarily at the synapse, that the time course of their clinical effect may correlate with their incorporation into various cell membranes within the CNS, and that they may thus bring about a fundamental alteration in cell membrane microstructure. The possible role of electroconvulsive therapy has also been considered. The corollary of this argument is that the affective disorders may be genetically determined diseases of cell membrane microstructure.  相似文献   
48.
Zusammenfassung Bericht über ?dintraoperative maschinelle autotransfusion?, kombiniert mit ?pr?operativer plasmapherese?. Mit maschineller autotransfusion kann intraoperativer blutverlust durch rückführung eigener erythrozyten halbiert werden. In kombination mit pr?operativer plasmapherese werden weitere fremdblutkonserven eingespart. übertragung von infektionskrankheiten und erzeugung irregul?rer antikōrper kōnnen verhindert werden. Bei der derzeitigen AIDS-situation wird das infektionsrisiko auf null reduziert.   相似文献   
49.
We have reviewed some of the factors which contribute to lung damage by various toxicants. These include disposition of the chemical, its metabolism, individual cell type susceptibility and the potential for the tissue to repair. We have discussed the use of biochemical parameters to measure the functional activity of individual cell types in order to predict the damage to specific cell types and concluded that careful morphological analysis of lung tissue is likely to provide a more sensitive and informative measure of specific cell type injury. However, in order to investigate the mechanism of toxicity of pulmonary toxicants it is essential to establish the primary biochemical event that leads to cell damage and morphological change. The importance of separating the relevant biochemical change(s) from the cascade of biochemical events associated with dead and dying cells and the reparative response of the lung is emphasised.This report results from a discussion sponsored and organised by the Advisory Subgroup in Toxicology (AST) of the European Science Foundation's Standing Committee for the European Medical Research Councils and held at the Medical Research Council Toxicology Unit, Carshalton, U. K. Those taking part were: W. N. Aldridge (AST; as above); J. Bignon (Unit for Research in Renal and Pulmonary Pathology, University of Paris, Creteil, France); P. H. Burri (Section of Developmental Biology, Institute of Anatomy, University of Berne, Switzerland); G. M. Cohen (as above); D. Dinsdale (MRC Toxicology Unit, Carshalton U. K.); P. Hedqvist (Dept. of Physiology, Karolinska Institute, Stockholm, Sweden); D. Henschler (AST; Dept. of Toxicology and Pharmacology, University of Wurzburg, FDR); G. J. Laurent (Biochemistry Unit, Cardiothoracic Institute, University of London, London, U. K.); R. Lauwerys (AST Industrial and Medical Toxicology Unit, University of Louvain, Brussels, Belgium); F. Lembeck (AST; Dept. for Experimental and Clinical Pharmacology, University of Graz, Austria); N. Lery (AST; Poison Control Centre, Lyon, France); P. Moldeus (Dept. of Forensic Medicine, Karolinska Institute, Stockholm, Sweden); B. Nemery (MRC Toxicology Unit, Carshalton, U. K.); A. Saria (Dept. for Experimental and Clinical Pharmacology, University of Graz, Austria); L. L. Smith (as above);B. Terracini (AST; Dept. of Pathology and Cancer Epidemiology, University of Turin, Italy)  相似文献   
50.
多希紫杉醇联合顺铂治疗晚期非小细胞肺癌疗效观察   总被引:1,自引:0,他引:1  
目的观察和评价多希紫杉醇联合顺铂(DP方案)治疗晚期非小细胞肺癌的疗效和毒性。方法将我科近几年收治的48例晚期非小细胞肺癌患者随机分为治疗组和对照组。治疗组采用多希紫杉醇联合顺铂(DP方案),对照组采用长春瑞滨联合顺铂(NP方案)。2周期化疗后进行疗效、毒性对比研究。结果治疗组和对照组近期有效率分别为45.5%和37.5%,疾病进展时间(TTP)分别为6.3和5.9个月,中位生存期分别为10.1和9.0个月,1年生存率分别为45.8%和39.4%,两组间比较差异均无显著性(P>0.05)。治疗组在恶心呕吐、骨髓抑制等毒性反应发生率方面低于对照组,差异有显著性(P<0.05)。结论多希紫杉醇联合顺铂治疗晚期非小细胞肺癌与NP方案相比较,疗效相似,但毒性反应低于NP组,患者更易耐受,可广泛应用于临床。  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