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   1896篇
  免费   152篇
  国内免费   10篇
耳鼻咽喉   19篇
儿科学   110篇
妇产科学   84篇
基础医学   201篇
口腔科学   34篇
临床医学   131篇
内科学   535篇
皮肤病学   68篇
神经病学   170篇
特种医学   70篇
外科学   366篇
综合类   10篇
一般理论   3篇
预防医学   38篇
眼科学   113篇
药学   51篇
肿瘤学   55篇
  2023年   13篇
  2022年   17篇
  2021年   49篇
  2020年   32篇
  2019年   40篇
  2018年   62篇
  2017年   30篇
  2016年   52篇
  2015年   59篇
  2014年   73篇
  2013年   87篇
  2012年   139篇
  2011年   153篇
  2010年   91篇
  2009年   65篇
  2008年   116篇
  2007年   141篇
  2006年   95篇
  2005年   103篇
  2004年   104篇
  2003年   83篇
  2002年   78篇
  2001年   45篇
  2000年   40篇
  1999年   21篇
  1998年   15篇
  1997年   12篇
  1996年   10篇
  1995年   15篇
  1994年   21篇
  1993年   15篇
  1992年   17篇
  1991年   11篇
  1990年   11篇
  1989年   15篇
  1988年   12篇
  1987年   20篇
  1986年   14篇
  1985年   16篇
  1984年   13篇
  1983年   6篇
  1982年   6篇
  1980年   3篇
  1979年   4篇
  1978年   5篇
  1976年   3篇
  1974年   5篇
  1972年   2篇
  1971年   3篇
  1966年   3篇
排序方式: 共有2058条查询结果,搜索用时 31 毫秒
1.
背景与研究目的:静脉曲张破裂出血是肝硬化的一个主要并发症,与6周内20%的死亡率有关。目前国际指南推荐肝硬化患应常规行上消化道内镜检查(食管胃十二指肠内镜检查,EGD)来筛查是否有食管静脉曲张。新近出现的食管胶囊内镜在对胃食管反流和Barrett食管的研究中已经显示出准确的诊断效应。该研究比较胶囊内镜和EGD对肝硬化患食管胃底静脉曲张和门脉高压性胃病的检出率。患与方法:在3个中心进行了先导试验。有进行EGD临床指征的肝硬化患,在EGD检查后48h内用胶囊内镜来筛查或监视食管静脉曲张。研究采用盲法,即由1名事先不知道患病史和EGD检查结果的研究评估胶囊视频成像。结果:在32例纳入的患中,EGD和胶囊内镜检查发现有食管静脉曲张23例患。有1例患经胶囊内镜发现有轻度静脉曲张,但EGD未检出。胶囊内镜和EGD诊断食管静脉曲张和门脉高压性胃病的总体一致性分别为96.9%和90.6%。没有与胶囊内镜相关的不良事件。  相似文献   
2.
3.
This study examined the effect of acute and chronic administration of the selective 5-HT3 receptor antagonist BRL 46470A, an analog of granisetron, on the number of spontaneously active dopamine (DA) cells in the substantia nigra pars compacta (A9 or SNC) and the ventral tegmental area (A10 or VTA) in the rat. In the A10 area, the acute administration of BRL 46470A decreased the number of spontaneously active DA cells at a dose of 0.1 mg/kg (0.28 μmol/kg) ip, yet increased the number of spontaneously active DA cells at a dose of 0.3 mg/kg (0.84 μmol/kg). The chronic administration (21 days) of BRL 46470A appeared to produce a multiphasic dose-response curve. Thus, the chronic treatment with BRL 46470A increased the number of spontaneously active A10 DA cells at 0.03 (0.084 μmol) and 0.3 mg/kg, but decreased the number of spontaneously active A10 DA cells at a dose of 0.1 mg/kg. In contrast, BRL 46470A did not decrease the number of spontaneously active A9 DA cells after either acute or chronic administration (0.01-0.3 mg/kg). However, BRL 46470A did increase the number of spontaneously active A9 DA cells at acute and chronic doses similar to those that were effective in A10. The iv administration of (+)-apomorphine (APO) not only failed to reverse the decrease produced by chronic administration of BRL 46470A at 0.1 mg/kg, but further decreased the number of spontaneously active A10 DA cells. Similar to the results obtained with granisetron, the pretreatment of naive rats with either 0.01 or 0.1 mg/kg iv of BRL 46470A significantly potentiated (2-fold) the suppressant action of APO on the basal firing rate of A10, but not A9 DA cells. Overall, our results indicate that similar to granisetron, chronic BRL 46470A at 0.1 mg/kg selectively decreases the number of spontaneously active A10 DA cells, via a mechanism not related to depolarization inactivation. Presently, it is not clear what factors may contribute to the multiphasic dose-response curve of BRL 46470A. © 1994 Wiley-Liss, Inc.  相似文献   
4.
Background: The cardiotoxic mechanism of local anesthetics may include interruption of cardiac sympathetic reflexes. The authors undertook this investigation to determine if clinically relevant concentrations of bupivacaine and levobupivacaine interfere with exocytotic norepinephrine release from cardiac sympathetic nerve endings.

Methods: Rat atria were prepared for measurements of twitch contractile force and 3[H]-norepinephrine release. After nerve endings were loaded with 3[H]-norepinephrine, the tissue was electrically stimulated in 5-min episodes during 10 10-min sampling periods. After each period, a sample of bath fluid was analyzed for radioactivity and 3[H]-norepinephrine release was expressed as a fraction of tissue counts. Atria were exposed to buffer alone during sampling periods 1 and 2 (S1 and S2). Control atria received saline (100 [mu]l each, n = 6 atria) in S3-S10. Experimental groups (n = 6 per group) received either bupivacaine or levobupivacaine at concentrations (in [mu]M) of 5 (S3-S4), 10 (S5-S6), 30 (S7-S8), and 100 (S9-S10).

Results: Bupivacaine and levobupivacaine decreased stimulation-evoked fractional 3[H]-norepinephrine release with inhibitory concentration 50% values of 5.1 +/- 0.5 and 6.1 +/- 1.3 [mu]m. The inhibitory effect of both local anesthetics (~70%) approached that of tetrodotoxin. Local anesthetics abolished the twitch contractions of atria with inhibitory concentration 50% values of 12.6 +/- 5.0 [mu]m (bupivacaine) and 15.7 +/- 3.9 [mu]m (levobupivacaine). In separate experiments, tetrodotoxin inhibited twitch contractile force by only 30%.  相似文献   

5.
6.
A rare case is reported of a young woman who suffered from suprascapular nerve entrapment syndrome (SNES) of the right side and two years later developed the same syndrome on the left. At the first operation an anomalous bifid transverse ligament was found and cut. The combination of pressure effect from the congenital defect together with frequent protraction of the shoulder due to her work as a physical education teacher caused triggering of the SNES. The clinical course, electromyographic findings, and differential diagnosis are reported. Cutting of the anomalous ligament on both sides brought relief from pain, weakness, and atrophy of the shoulder muscles, enabling the patient to return to work.  相似文献   
7.
8.
9.
10.
Lamotrigine in the treatment of painful diabetic neuropathy   总被引:1,自引:0,他引:1  
An open trial was conducted to study the potential efficacy of lamotrigine, a novel antiepileptic agent that blocks voltage-sensitive sodium channels and inhibits the release of glutamate, in relieving the pain associated with diabetic neuropathy. Subsequent to a 1 week washout period from previous analgesics, lamotrigine was administered at a dose of 25 mg/day for 1 week. The dose was doubled on a weekly basis up to 400 mg/day over 6 weeks. The McGill pain questionnaire (MPQ), spontaneous pain and a series of mechanical and thermal stimuli-induced pain were measured with the use of 0–100 visual analogue scale (VAS), on seven office visits. Pain level was also recorded by each patient twice daily, 1 week before, during, and 2 weeks after the treatment period with the use of a 0–10 numerical pain scale (NPS). Quantitative mechanical (Von Frey filaments) and thermal testing (QTT), and routine blood tests were performed at the beginning and at the end of the study. Thirteen patients completed the study. Spontaneous pain measured by VAS and NPS gradually dropped from a baseline of 49 ± 8 and 6.8 ± 0.6, to 20 ± 8.6 ( p < 0.001) and 4.3 ± 0.9 ( p < 0.001), respectively, at the end of the treatment period. Similarly, cold allodynia dropped from 38 ± 9.2 to 16 ± 15.3 ( p = 0.01), and the MPQ score from 13.6 ± 0.8 to 11.0 ± 1.5 ( p < 0.01). In contrast, no significant changes were found in the QTT, mechanical pain thresholds and laboratory results. Two patients were withdrawn from the study because of adverse effects. A long-term follow up showed that most patients were still using lamotrigine 6 months after the end of the study. The results of the study suggest that lamotrigine is potentially effective and safe in treating painful diabetic neuropathy.  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