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   669篇
  免费   33篇
  国内免费   14篇
耳鼻咽喉   1篇
儿科学   2篇
基础医学   129篇
口腔科学   1篇
临床医学   12篇
内科学   35篇
神经病学   373篇
特种医学   13篇
外科学   49篇
综合类   54篇
预防医学   6篇
药学   37篇
肿瘤学   4篇
  2023年   3篇
  2022年   8篇
  2021年   7篇
  2020年   8篇
  2019年   8篇
  2018年   10篇
  2017年   9篇
  2016年   11篇
  2015年   9篇
  2014年   22篇
  2013年   24篇
  2012年   14篇
  2011年   21篇
  2010年   30篇
  2009年   15篇
  2008年   19篇
  2007年   20篇
  2006年   34篇
  2005年   21篇
  2004年   20篇
  2003年   15篇
  2002年   23篇
  2001年   15篇
  2000年   17篇
  1999年   6篇
  1998年   17篇
  1997年   19篇
  1996年   19篇
  1995年   15篇
  1994年   14篇
  1993年   12篇
  1992年   7篇
  1991年   6篇
  1990年   13篇
  1989年   9篇
  1988年   6篇
  1987年   10篇
  1986年   11篇
  1985年   28篇
  1984年   21篇
  1983年   24篇
  1982年   21篇
  1981年   26篇
  1980年   21篇
  1979年   10篇
  1978年   8篇
  1977年   4篇
  1976年   2篇
  1975年   3篇
  1974年   1篇
排序方式: 共有716条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: Impaired neuropsychological test performance, especially on tests of executive function and attention, is often seen in children diagnosed with autism spectrum disorders (ASD). Structures involved in fronto-striatal circuitry, such as the caudate nucleus, may support these cognitive abilities. However, few studies have examined caudate volumes specifically in children with ASD, or correlated caudate volumes to cognitive ability. METHODS: Neuropsychological test scores and caudate volumes of children with ASD were compared to those of children with bipolar disorder (BD) and of typically developing (TD) children. The relationship between test performance and caudate volumes was analyzed. RESULTS: The ASD group displayed larger right and left caudate volumes, and modest executive deficits, compared to TD controls. While caudate volume inversely predicted performance on the Wisconsin Card Sorting Test in all participants, it differentially predicted performance on measures of attention across the ASD, BD and TD groups. CONCLUSIONS: Larger caudate volumes were related to impaired problem solving. On a test of attention, larger left caudate volumes predicted increased impulsivity and more omission errors in the ASD group as compared to the TD group, however smaller volume predicted poorer discriminant responding as compared to the BD group.  相似文献   
2.
Summary Rats were treated with desipramine 5mg/kg, nomifensine 10mg/kg, zimelidine 25 mg/kg or with 0.9% sodium chloride once a day during the second and third weeks after birth, and brain stem, caudate/putamen and cortical monoamines, and caudate/putamen dopamine D1 (3[H]SCH 23390) and D2 (3[H]spiroperidol) receptor binding were measured when rats were at two months of age. In the brain stem, the concentration of 3-methoxy-4-hydroxy-phenyl glycol was increased in nomifensine rats and the ratio of 5-hydroxyindoleacetic acid to 5-hydroxytryptamine was increased in zimelidine rats. In the caudate/putamen, the concentrations of 3,4-dihydroxyphenylacetic acid and homovanillic acid and the ratio of homovanillic acid to dopamine were increased in desipramine rats; neither3[H]SCH 23390 nor3[H]spiroperidol binding were affected by any of the three monoamine uptake inhibiting antidepressants studied. In the cortex, the ratio of 5-hydroxyindoleacetic acid to 5-hydroxytryptamine was increased in desipramine and zimelidine rats. The findings suggest that desipramine but not nomifensine increases the metabolism of dopamine in the caudate/ putamen and nomifensine but not desipramine increases the metabolism of norepinephrine in the brain stem, and furthermore that the metabolism of serotonin is affected by desipramine as well as by zimelidine. It is possible that also treatment of women with these drugs during late pregnancy causes long-lasting changes in the brain of human fetus.  相似文献   
3.
肝尾叶切除     
肝尾叶深藏于肝门结构与下腔静脉之间,具有独立的管道系统,手术切除风险较大,作者结合2例肝尾叶切除的体会,复习文献,对肝尾叶的解剖、影像学特征、切除指征及手术方法进行了讨论。  相似文献   
4.
实验在15只家兔上进行。以玻璃微电极记录尾核头部(DHCN)痛相关单位,刺激扣带回,观察痛相关单位电活动的变化。在70只DHCN痛相关单位中,有44个对刺激扣带回表现兴奋反应(62.9%),17个呈抑制反应(24.3%),9个变化不明显(12.8%)。进一步观察了52只痛相关单位,在刺激扣带回后再施伤害刺激,43个原痛兴奋单位中15个转为抑制(34.9%),16个进一步兴奋(37.2%)12个无变化(27.9%);原9个痛抑制单位,8个转为兴奋,1个变化不明显。提示,扣带回可通过其下行活动,调制伤害性冲动在尾核水平上的传递。  相似文献   
5.
目的研究多巴胺对正常大鼠和吗啡成瘾大鼠中枢的伤害性刺激的传递的影响。方法在给予坐骨神经伤害性刺激后,记录中枢痛兴奋神经元的电活动,观察多巴胺对正常大鼠和吗啡成瘾大鼠中枢痛兴奋神经元电活动的影响。结果正常大鼠中,多巴胺使尾核痛兴奋神经元的痛诱发放电潜伏期缩短,说明多巴胺可使正常大鼠尾核痛兴奋神经元的活动增强,多巴胺受体拮抗剂氟哌利多可以阻断这种作用。吗啡大鼠中,多巴胺使尾核痛兴奋神经元的痛诱发放电潜伏期延长,说明多巴胺可使吗啡大鼠尾核痛兴奋神经元的活动减弱。结论脑室注射多巴胺后,正常大鼠和吗啡成瘾大鼠的尾核对痛刺激的反应存在着差异。  相似文献   
6.
Electrophysiological mapping criteria were employed to identify visual areas 20a, 20b, 21a, 21b, PMLS, AMLS, ALLS, PLLS, DLS, VLS, and PS in the cat, and to guide placement of tracer deposits. Anterograde tracer methods were used to study the corticostriatal projections of these extrastriate visual areas. The experiments demonstrate that all 11 extrastriate areas send projections to two distinct regions within the striatum, an extensive longitudinal zone within the caudate nucleus, and a more compact region within the posterolateral putamen. Cortical visual projections to the putamen terminate in relatively compact sheets or slabs, and appear to overlap extensively, while those to the caudate nucleus are irregularly patchy and more widely dispersed. Retrograde tracer deposits into the visual recipient zone of the caudate nucleus reveal substantial convergence of other cortical inputs to this same domain. Aspects of visuotopic organization are preserved in the visual projections to both the putamen and the caudate nucleus, but unequivocal retinotopic organization could not be inferred from the available material. Ten of the eleven extrastriate visual area also project topographically onto the visual zone of the claustrum. Area PS does not appear to contribute to the corticoclaustral projections. Five of the extrastriate visual areas (ALLS, PLLS, DLS, VLS, PS) also send sparse projections to the amygdaloid complex. c 1993 Wiley-Liss, Inc.  相似文献   
7.
A model of instrumental defensive reflexes associated with the maintenance of a specific posture was used in chronic experiments with four dogs to demonstrate the preferential inhibitory influence of preliminary low-frequency stimulation (2 impulses/sec) of the head of the caudate nucleus in the right and left hemispheres on the electromyographic and mechanographic components of the instrumental defensive reflex effecting the reflex motor program. Subjected to the greatest changes were the postural, components of the electromyogram, which permits the postulate as to the importance of the caudate head in the organization of posture. It was shown that the caudate head is bilaterally involved in the prerelease processes preceeding the instrumental response. At the same time, the difficulty of inhibiting the performance of the actual instrumental task- the avoidance of an electric current- was noted during stimulation of the caudate head in a system of instrumental defensive reflexes.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 68, No. 11, pp. 1488–1499, November, 1982.  相似文献   
8.
肝尾状叶的外科解剖及其临床应用   总被引:1,自引:0,他引:1  
在42例成人肝脏标本上,研究了肝尾状叶的形态,动脉、静脉和肝管的分布特征;尾状叶常有3个突起,即尾状突、乳头突和下腔静脉后突,且变异较大;尾状叶有两个恒定的蒂,其结构排列由浅入深分别是门静脉支、肝动脉支和肝管。尾状叶静脉有2~5支,其中以3支居多,主要汇入下腔静脉肝后段的中、下1/3部的左前壁。中结合解剖学研究总结了施行肝尾状叶肿瘤切除术的方法和经验。  相似文献   
9.
10.
网膜囊上隐窝的CT应用解剖   总被引:4,自引:1,他引:4  
在42套腹部断面标本及50例整尸上观察到:网膜囊上隐窝呈“V”形间隙围绕肝尾状叶,前界为小网膜及肝左叶,后界是膈,顶由肝冠状韧带或膈形成,下抵胰,左邻食管;在正中矢状面上均出现肝尾状叶,且尾状叶套入或游离于网膜囊上隐窝。这些结果对在 CT 图像上鉴别尾状叶周围的积液及肿块具有重要意义。  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