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   259610篇
  免费   24497篇
  国内免费   6685篇
耳鼻咽喉   3466篇
儿科学   4503篇
妇产科学   3979篇
基础医学   18510篇
口腔科学   7747篇
临床医学   25219篇
内科学   23330篇
皮肤病学   2844篇
神经病学   11132篇
特种医学   6853篇
外国民族医学   14篇
外科学   22507篇
综合类   46010篇
现状与发展   19篇
一般理论   46篇
预防医学   32620篇
眼科学   2271篇
药学   25946篇
  572篇
中国医学   43019篇
肿瘤学   10185篇
  2024年   1299篇
  2023年   5458篇
  2022年   10094篇
  2021年   13167篇
  2020年   13029篇
  2019年   13313篇
  2018年   11834篇
  2017年   10916篇
  2016年   9939篇
  2015年   9271篇
  2014年   19101篇
  2013年   18408篇
  2012年   16908篇
  2011年   17911篇
  2010年   14406篇
  2009年   12098篇
  2008年   11008篇
  2007年   11240篇
  2006年   9364篇
  2005年   7893篇
  2004年   6461篇
  2003年   5696篇
  2002年   4382篇
  2001年   3698篇
  2000年   3217篇
  1999年   2580篇
  1998年   2060篇
  1997年   1825篇
  1996年   1452篇
  1995年   1384篇
  1994年   1254篇
  1993年   1093篇
  1992年   994篇
  1991年   929篇
  1990年   778篇
  1989年   749篇
  1988年   683篇
  1987年   628篇
  1986年   561篇
  1985年   1825篇
  1984年   2091篇
  1983年   1304篇
  1982年   1728篇
  1981年   1210篇
  1980年   1038篇
  1979年   910篇
  1978年   743篇
  1977年   561篇
  1976年   699篇
  1975年   482篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
精神科儿少住院患者的42年资料回顾   总被引:2,自引:0,他引:2  
目的了解从1958年8月本院正式成立儿童精神科以来,42年中儿童住院病人的情况,以掌握及了解儿童和少年精神障碍的发展趋势。方法从1958年8月到2000年9月之间住院的所有病人的病历共1327份,逐一记载所需资料内容,并将所有资料进行分析。结果患儿年龄主要集中在13—14岁,并涉及3—16岁各年龄段。以儿童和少年期最多,文化程度以初中和小学居多。在早期,精神障碍诊断不规范,90年代后,诊断趋于标准化,位于前五位的诊断是:精神分裂症、精神发育迟滞、脑器质性精神障碍、情感性精神障碍、行为障碍。90年代以来,每年住院儿童病人数量均呈增长趋势。结论在住院期间,儿童少年病人既要接受治疗,又需进行儿童间交友训练,而在成人精神科病房,在这一点上不能满足住院患儿的需要,不利于儿童和少年的综合治疗,所以在我院开设儿童青少年病房有重要的意义。  相似文献   
992.
胃癌组织中KAI1、nm23及P53的表达及其临床意义   总被引:5,自引:4,他引:1  
目的:探讨正常胃黏膜、不典型增生胃黏膜及癌组织中KAI1、nm23及P53蛋白的表达.方法:应用SP法免疫组化检测22例正常胃黏膜,65例不典型增生胃黏膜及74N胃癌组织中的KAI1、nm23及P53蛋白的表达.结果:正常胃黏膜、不典型增生胃黏膜及胃癌组织中,KAI1和nm23阳性率呈降低趋势,组间差异性有统计学意义(x2=20.885, P<0.001;x2=29.133,P<0.05):P53蛋白阳性表达率呈增加趋势,组间差异性有统计学意义(x2=21.954,P<0.001).Fisher精确概率检验显示:在胃癌组中不同的浸润深度、有无淋巴结转移和脉管侵犯组内KAI1、nm23及 P53组阳性表达率的差异性有统计学意义(x2 =20.885,P<0.001;x2=29.133,P<0.05;x2= 21.954,P<0.001);而在年龄、性别组间的差异性无统计学意义.Spearman等级相关分析显示 KAI1与nm23表达呈正相关(r=0.859,P<0.05); KAI1与P53表达呈负相关(r=-0.859,P<0.05), nm23与P53表达呈负相关(r=-0.874,P<0.05) 结论:抑癌基因KAI1与nm23的缺失以及P53 蛋白的过表达可能是胃癌发生、发展及浸润和转移的重要原因之一.  相似文献   
993.
食管贲门癌术后早期肠内营养支持的应用研究   总被引:2,自引:0,他引:2  
目的研究食管贵门癌切除术中放置鼻肠营养管进行早期肠内营养,在维持机体营养、促进恢复履在防治术后并发症的作用。方法将90例管责门癌病人随机分为A、B两组,A组术后常规静脉输液,B组术中放置鼻肠营养管,术后第1天给予肠内营养。两组病人监测术前、术后第10天的体重、肠功能恢复排气时间、疲劳评分,吻合口瘘反感染并发症的发生率。结果两组病人在体重、肠功能恢复方面存在明显差异(P〈0.05),在术后并发症方面差异明显(P〈0.01)。结论鼻肠营养管进行早期肠内营养具有易于维持机体营养,促进机体康复,尽快恢复正氮平衡,减少术后并发症的优点。  相似文献   
994.
We evaluated the effects of allogeneic bone marrow stromal cell treatment of stroke on functional outcome, glial–axonal architecture, and immune reaction. Female Wistar rats were subjected to 2 h of middle cerebral artery occlusion. Rats were injected intravenously with PBS, male allogeneic ACI – or syngeneic Wistar –bone marrow stromal cells at 24 h after ischemia and sacrificed at 28 days. Significant functional recovery was found in both cell-treated groups compared to stroke rats that did not receive BMSCs, but no difference was detected between allogeneic and syngeneic cell-treated rats. No evidence of T cell priming or humoral antibody production to marrow stromal cells was found in recipient rats after treatment with allogeneic cells. Similar numbers of Y-chromosome+ cells were detected in the female rat brains in both groups. Significantly increased thickness of individual axons and myelin, and areas of the corpus callosum and the numbers of white matter bundles in the striatum were detected in the ischemic boundary zone of cell-treated rats compared to stroked rats. The areas of the contralateral corpus callosum significantly increased after cell treatment compared to normal rats. Processes of astrocytes remodeled from hypertrophic star-like to tadpole-like shape and oriented parallel to the ischemic regions after cell treatment. Axonal projections emanating from individual parenchymal neurons exhibited an overall orientation parallel to elongated radial processes of reactive astrocytes of the cell-treated rats. Allogeneic and syngeneic bone marrow stromal cell treatment after stroke in rats improved neurological recovery and enhanced reactive oligodendrocyte and astrocyte related axonal remodeling with no indication of immunologic sensitization in adult rat brain.  相似文献   
995.
167例老年人心力衰竭的循证治疗实践   总被引:1,自引:0,他引:1  
目的:探讨老年人充血性心力衰竭(CHF)的循证医学(EBM)标准化治疗。方法:167例确诊为CHF的住院患者,年龄60 ̄90岁,平均(74.38±6.84)岁,按照循证医学的基本原理,在病因、诱因和改善心衰症状的基础上,强调能改善预后的神经内分泌拮抗剂的应用。结果:本组167例CHF患者,显效96例(57.5%),有效62例(37.1%),总有效率94.6%,死亡9例(5.4%)。神经内分泌拮抗剂践行率分别为:ACEI类119例(71.3%),β受体阻滞剂69例(41.32%),醛固酮拮抗剂88例(52.7%);随访6 ̄36个月,平均(16.25±9.30)个月;107例(67.7%)再入院1 ̄5次,院外死亡6例。结论:按照EBM原理对老年CHF患者制定的个体化治疗方案,效果理想。在老年CHF患者中,神经内分泌拮抗剂践行率较低,可能是再住院次数多的原因之一。  相似文献   
996.
Background:   The aim of this study is to construct a simple screening test for the risk of falls in community-dwelling elder persons.
Methods:   A total of 1378 community-dwelling people aged 65 years and older in five different communities in Japan were asked to answer a self rated questionnaire including 22 items covering physical, cognitive, emotional and social aspects of functioning and environmental factors. At a six-month follow-up, the outcome of fall occurrence and the number of falls was ascertained by social workers, health visitors or nurses.
Results:   Five out of 22 items were selected using a logistic regression model. Using this five-item version, a screening test was constructed, and at the best cut-off point, the sensitivity and specificity were 68% and 70%, respectively. The validity of this scale was tested on persons with cognitive dysfunction.
Conclusion:   The simplicity and the predictive validity of the screening test support the use of this test in health check ups or general outpatient facilities.  相似文献   
997.
Treatment and prognostic factors in patients with hepatocellular carcinoma.   总被引:4,自引:0,他引:4  
INTRODUCTION: Hepatocellular carcinoma is a leading cause of death from cancer worldwide. Survival of patients depends on tumor extension and liver function, but yet there is no consensual prognostic model. AIMS: To evaluate the influence on survival of pretreatment parameters (clinico-laboratorial, liver function, tumor extension, Okuda and Cancer of the Liver Italian program (CLIP) staging) and treatment modalities. METHODS: We retrospectively analyzed 207 patients, diagnosed between 1993 and 2003. The initial treatment was: surgery--six patients; radiofrequency ablation--21; percutaneous ethanol injection--29; transarterial chemoembolization--49; tamoxifen--49; supportive care alone--53. Factors determining survival were assessed by Kaplan-Meier method and Cox regression models. RESULTS: Median survival was 24 months. In univariate analysis, Child-Pugh classification and Model for end-stage liver disease (MELD) score, portal vein thrombosis (PVT), tumor size, number of lesions, Okuda and CLIP scores were all associated with prognosis (P < 0.001). Alpha-fetoprotein levels were not predictive of survival. Independent predictors of survival were ascites, bilirubin, PVT and therapeutic modalities (P < 0.001). In early stage hepatocellular carcinoma (HCC), survival was similar for both percutaneous ablation modalities, either radiofrequency or ethanol injection (P = NS). In advanced HCC, survival was better in patients receiving tamoxifen than supportive care alone (P < 0.001). CONCLUSION: This study reinforces the importance of baseline liver function (Child-Pugh classification and MELD score) in the survival of patients with HCC, although staging systems allowed the stratification of patients in different prognostic groups. Ascites, bilirubin and PVT were independent pretreatment predictors of survival. All treatments influenced the patient's outcome, whether in early or advanced stages.  相似文献   
998.
OBJECTIVE: To clarify the role played by tissue factor pathway inhibitor (TFPI) in pregnancy hypertension. METHODS: Using enzyme-linked immunosorbent assays, hemostatic measurements were obtained for women with pre-eclampsia (n=51), nonproteinuric hypertension of pregnancy (n=62), postpartum pre-eclampsia 24 h after childbirth (n=31), and no hypertension (healthy pregnant controls, n=100). RESULTS: There was a significant increase in circulating free TFPI levels in women with pre-eclampsia (9.7+/-6.2 ng/mL) or nonproteinuric hypertension of pregnancy (8.3+/-5.3 ng/mL) compared with healthy controls (5.3+/-2.1 ng/mL). In women with pre-eclampsia the levels remained elevated after placental delivery (10.6+/-4.0 ng/mL). Free protein S levels were significantly higher in women with pre-eclampsia (40.0%+/-10.7%), nonproteinuric hypertension of pregnancy (37.1%+/-12.5%), or postpartum pre-eclampsia (39.3%+/-9.1%) than in healthy pregnant controls (32.2%+/-8.5%). CONCLUSION: Increased levels of the physiologically active free forms of TFPI and free protein S, 2 coagulation inhibitors, may protect women with pregnancy-induced hypertension from the risks of hemostatic activation.  相似文献   
999.
人心和山羊心脏上、下腔静脉肌袖大体解剖   总被引:2,自引:2,他引:0  
目的:观测人和山羊上、下腔静脉肌袖结构特点,为治疗局灶性心房颤动积累解剖学资料。方法:采用大体解剖方法观测人心(20例)和羊心(40例)的上、下腔静脉及其表面的心肌纤维。结果:人心上腔静脉肌袖的长和宽分别为(1.91±0.39)cm、(2.41±0.26)cm,下腔静脉肌袖的长和宽分别为(1.32±0.32)cm,(3.06±0.52)cm;羊心上(前)腔静脉肌袖的长和宽分别为(1.41±1.00)cm、(1.05±0.26)cm,下(后)腔静脉肌袖的长和宽分别为(0.81±0.48)cm,(1.03±0.28)cm。人和羊心脏的上腔静脉肌袖出现率均为100%;下腔静脉肌袖的出现率分别为88.89%和98%。肌纤维多数来源于右心房前后壁,也有来自于左心房或左右心房的。结论:①上腔静脉肌袖是人和羊普遍存在的解剖结构,人的下腔静脉肌袖出现率明显低于羊,可能是上腔静脉肌袖引起局灶性心房颤动多于下腔静脉肌袖的解剖学基础。②上腔静脉肌袖是构成左右房的又一重要通路。  相似文献   
1000.
目的研究人脑不同级别胶质瘤中白细胞介素(IL)-6,信号传导和转录活化因子3(STAT3)和血管内皮生长因子(VEGF)的表达,探讨IL-6、STAT3和VEGF与肿瘤病理级别和侵袭性的关系。方法采用免疫组织化学法,检测70例人脑胶质瘤,10例脑膜瘤和5例正常脑组织中IL-6、STAT3和VEGF的表达。结果胶质瘤中IL-6、STAT3和VEGF的表达水平在高级别组(Ⅲ、Ⅳ级)明显高于低级别组(Ⅰ、Ⅱ级),两组间差异有统计学意义(P〈0.01),STAT3的表达与IL-6和VEGF的表达均呈正相关(P〈0.01)。结论IL-6、STAT3和VEGF的表达与胶质瘤的恶性程度有密切关系;且三者协同在胶质瘤发生、发展过程中起重要作用。三者的相关性证实VEGF基因由STAT3蛋白调节,而STAT3又由IL-6刺激活化。  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