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   21286篇
  免费   455篇
  国内免费   501篇
耳鼻咽喉   598篇
儿科学   1274篇
妇产科学   389篇
基础医学   2084篇
口腔科学   713篇
临床医学   1100篇
内科学   4939篇
皮肤病学   371篇
神经病学   1547篇
特种医学   565篇
外科学   3603篇
综合类   279篇
一般理论   10篇
预防医学   2240篇
眼科学   492篇
药学   1293篇
中国医学   263篇
肿瘤学   482篇
  2024年   4篇
  2023年   27篇
  2022年   62篇
  2021年   83篇
  2020年   92篇
  2019年   101篇
  2018年   126篇
  2017年   57篇
  2016年   133篇
  2015年   78篇
  2014年   126篇
  2013年   60篇
  2012年   1994篇
  2011年   2269篇
  2010年   524篇
  2009年   270篇
  2008年   1743篇
  2007年   1987篇
  2006年   1752篇
  2005年   1885篇
  2004年   1803篇
  2003年   1747篇
  2002年   1639篇
  2001年   1101篇
  2000年   1601篇
  1999年   727篇
  1998年   87篇
  1997年   29篇
  1996年   21篇
  1995年   24篇
  1994年   26篇
  1993年   5篇
  1992年   4篇
  1991年   6篇
  1990年   5篇
  1989年   8篇
  1988年   8篇
  1987年   4篇
  1986年   3篇
  1984年   3篇
  1983年   5篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
  1978年   2篇
  1976年   1篇
  1967年   1篇
  1966年   1篇
  1957年   1篇
  1942年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Mechanisms of Cardioprotection by Volatile Anesthetics   总被引:2,自引:0,他引:2  
  相似文献   
12.
Background: Manipulations that cause hypersensitivity to visceral stimuli have been shown to also result in hypersensitivity to somatic stimuli coming from convergent dermatomes, but the converse has not been examined. The authors tested whether lumbar spinal nerve ligation in rats, a common model of neuropathic pain that results in hypersensitivity to somatic stimuli, also leads to hypersensitivity to visceral stimuli coming from convergent dermatomes and whether pharmacology of inhibition differed between these two sensory modalities.

Methods: Female Sprague-Dawley rats were anesthetized, and the left L5 and L6 spinal nerves were ligated. Animals received either intrathecal saline or milnacipran (0.1-3 [mu]g), and withdrawal thresholds to mechanical testing in the left hind paw, using von Frey filaments, and visceral testing, using balloon colorectal distension, were determined.

Results: Nerve ligation resulted in decreases in threshold to withdrawal to somatic mechanical stimulation (from 13 +/- 1.8 g to 2.7 +/- 0.7 g) and also in decreases in threshold to reflex response to visceral stimulation (from 60 mmHg to 40 mmHg). Intrathecal milnacipran increased withdrawal threshold to somatic stimulation in a dose-dependent manner but failed to alter the response to noxious visceral stimulation.  相似文献   

13.
Background: Volatile anesthetic preconditioning (APC) protects against myocardial ischemia-reperfusion (IR) injury, but the precise mechanisms underlying this phenomenon remain undefined. To investigate the molecular mechanism of APC in myocardial protection, the activation of nuclear factor (NF) [kappa]B and its regulated inflammatory mediators expression were examined in the current study.

Methods: Hearts from male rats were isolated, Langendorff perfused, and randomly assigned to one of three groups: (1) the control group: hearts were continuously perfused for 130 min; (2) the IR group: 30 min of equilibration, 15 min of baseline, 25 min of ischemia, 60 min of reperfusion; and (3) the APC + IR group: 30 min of equilibration, 10 min of sevoflurane exposure and a 5-min washout, 25 min of global ischemia, 60 min of reperfusion. Tissue samples were acquired at the end of reperfusion. NF-[kappa]B activity was determined by electrophoretic mobility shift assay. The NF-[kappa]B inhibitor, I[kappa]B-[alpha], was determined by Western blot analysis. Myocardial inflammatory mediators, including tumor necrosis factor [alpha], interleukin 1, intercellular adhesion molecule 1, and inducible nitric oxide synthase, were also assessed by Western blot analysis.

Results: Nuclear factor [kappa]B-DNA binding activity was significantly increased at the end of reperfusion in rat myocardium, and cytosolic I[kappa]B-[alpha] was decreased. Supershift assay revealed the involvement of NF-[kappa]B p65 and p50 subunits. APC with sevoflurane attenuated NF-[kappa]B activation and reduced the expression of tumor necrosis factor [alpha], interleukin 1, intercellular adhesion molecule 1, and inducible nitric oxide synthase. APC also reduced infarct size and creatine kinase release and improved myocardial left ventricular developed pressure during IR.  相似文献   

14.
Background: Adenosine triphosphate-regulated potassium channels mediate protection against myocardial infarction produced by volatile anesthetics and opioids. We tested the hypothesis that morphine enhances the protective effect of isoflurane by activating mitochondrial adenosine triphosphate-regulated potassium channels and opioid receptors.

Methods: Barbiturate-anesthetized rats (n = 131) were instrumented for measurement of hemodynamics and subjected to a 30 min coronary artery occlusion followed by 2 h of reperfusion. Myocardial infarct size was determined using triphenyltetrazolium staining. Rats were randomly assigned to receive 0.9% saline, isoflurane (0.5 and 1.0 minimum alveolar concentration [MAC]), morphine (0.1 and 0.3 mg/kg), or morphine (0.3 mg/kg) plus isoflurane (1.0 MAC). Isoflurane was administered for 30 min and discontinued 15 min before coronary occlusion. In eight additional groups of experiments, rats received 5-hydroxydecanoic acid (5-HD; 10 mg/kg) or naloxone (6 mg/kg) in the presence or absence of isoflurane, morphine, and morphine plus isoflurane.

Results: Isoflurane (1.0 MAC) and morphine (0.3 mg/kg) reduced infarct size (41 +/- 3%; n = 13 and 38 +/- 2% of the area at risk; n = 10, respectively) as compared to control experiments (59 +/- 2%; n = 10). Morphine plus isoflurane further decreased infarct size to 26 +/- 3% (n = 11). 5-HD and naloxone alone did not affect infarct size, but abolished cardioprotection produced by isoflurane, morphine, and morphine plus isoflurane.  相似文献   

15.
目的探讨儿童孤独症(CA)与多巴胺转运体(DAT1)440bp等位基因的关系。 方法陕西省纺织医院等于2004年3~8月,采用PCR技术对来自西安市两所康复中心的汉族CA儿童与DAT1基因多态性进行遗传关联分析。 结果(1)DAT1基因多态性中共观察到5种等位基因(320bp,360bp,440bp,480bp,520bp),6种基因型(480/480,480/320,520/480,480/360,480/440,440/440)。(2)使用相对危险度RR对CA与DAT1基因多态性的等位基因和基因型进行关联分析,显示480/440基因型和等位基因440与CA呈正关联,相对危险度分别为265和230,480/480基因型和等位基因480与CA呈负关联,相对危险度分别为064和077。但统计结果没有发现具有统计意义的差异。 结论中国汉族CA儿童与DAT1440bp等位基因无遗传关联。也许等位基因440bp与基因型480bp/440bp这两个因素是发病的风险因素,还有待今后的进一步研究。  相似文献   
16.
本文目的是检验一种用于量化和预测内镜检查患者的不良体验的一种问卷调查的可靠性。分别给予目前常规接受内镜检查的患者2份问卷(操作前及操作后)。第1份问卷包括人口统计学资料、既往内镜检查史、用药或饮酒史、患者期望值、操作前的焦虑及紧张程度。内镜检查后,重新确定患者的耐受性和意愿。内镜检查后对患者进行重复内镜检查的总体满意度或不情愿的主要结果评分≥5确定为“内镜检查的不良体验”(A EE)。148例受试者中有13例报告有AEE。通过对与不良反应如疼痛、紧张和操作期间的损伤情况明显相关的可靠分析,确定测定主要结果的项目。…  相似文献   
17.
18.
Background: A multidisciplinary effort was undertaken to determine whether patients could safely bypass the postanesthesia care unit (PACU) after same-day surgery by moving to an earlier time point evaluation of recovery criteria.

Methods: A prospective, outcomes research study with a baseline month, an intervention month, and a follow-up month was designed. Five surgical centers (three community-based hospitals and two freestanding ambulatory surgical centers) were utilized. Two thousand five hundred eight patients were involved in the baseline period, and 2,354 were involved in the follow-up period. Outcome measures included PACU bypass rates and adverse events. Intervention consisted of a multidisciplinary educational program and routine feedback reports.

Results: The overall PACU bypass rate (58%) was significantly different from baseline (15.9%, P < 0.001), for patients to whom a general anesthetic was administered (0.4-31.8%, P < 0.001), and for those given other anesthetic techniques (monitored anesthesia care, regional or local anesthetics; 29.1-84.2%, P < 0.001). During the follow-up period, the average (SD) recovery duration for patients who bypassed the PACU was significantly shorter compared to that for patients who did not bypass, 84.6 (61.5) versus 175.1 (98.8) min, P < 0.001, with no change in patient outcome. Patients receiving only short-acting anesthetics were 78% more likely (P < 0.002) to bypass the PACU after adjusting for various surgical procedures.  相似文献   

19.
黄色蔬菜可控制胃炎文/王增现代营养学家将蔬菜分为绿、黄、白三种颜色。例如,芥菜、苜蓿、油菜等为绿色,西红柿、胡萝卜、南瓜等为黄色;冬瓜、竹笋等为白色。现代医学研究证明,黄色蔬菜可控制胃炎。据医学研究成果报道,日本国立癌症中心研究所临床医学研究部部长津...  相似文献   
20.
目的:评估子宫肌瘤患者经子宫动脉栓塞术(UAE)治疗后临床症状严重程度、健康相关生活质量(HRQOL)的变化及对治疗满意度的调查。设计:对1998~2002年80例经UAE治疗的子宫肌瘤患者进行问卷调查,了解治疗的有效性、治疗前后的临床症状严重程度及HRQOL的变化。主要观察指标:UAE治疗后症状严重程度及HRQOL评分的变化。次要观察指标:患者满意度及子宫体积缩小程度。结果:64例(80.0%)患者完成了问卷,调查时间为UAE后平均32.1月(范围:57.5~6月)。UAE后子宫体积平均缩小26.3%(95%CI19.6~33.0),79例患者中17例(21.5%)于术后平均18.6月…  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