全文获取类型
收费全文 | 12171篇 |
免费 | 1277篇 |
国内免费 | 218篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 119篇 |
妇产科学 | 102篇 |
基础医学 | 1278篇 |
口腔科学 | 111篇 |
临床医学 | 1434篇 |
内科学 | 624篇 |
皮肤病学 | 44篇 |
神经病学 | 517篇 |
特种医学 | 232篇 |
外科学 | 395篇 |
综合类 | 3488篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 3433篇 |
眼科学 | 80篇 |
药学 | 946篇 |
14篇 | |
中国医学 | 443篇 |
肿瘤学 | 369篇 |
出版年
2024年 | 42篇 |
2023年 | 187篇 |
2022年 | 400篇 |
2021年 | 540篇 |
2020年 | 533篇 |
2019年 | 400篇 |
2018年 | 370篇 |
2017年 | 395篇 |
2016年 | 457篇 |
2015年 | 521篇 |
2014年 | 1072篇 |
2013年 | 1083篇 |
2012年 | 982篇 |
2011年 | 1005篇 |
2010年 | 776篇 |
2009年 | 673篇 |
2008年 | 771篇 |
2007年 | 590篇 |
2006年 | 542篇 |
2005年 | 447篇 |
2004年 | 351篇 |
2003年 | 320篇 |
2002年 | 212篇 |
2001年 | 148篇 |
2000年 | 139篇 |
1999年 | 94篇 |
1998年 | 98篇 |
1997年 | 75篇 |
1996年 | 53篇 |
1995年 | 46篇 |
1994年 | 41篇 |
1993年 | 31篇 |
1992年 | 30篇 |
1991年 | 40篇 |
1990年 | 17篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 23篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 21篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1969年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
近红外信息辐照对免疫抑制大鼠体液免疫功能的影响 总被引:1,自引:0,他引:1
本实验观察了近红外信息辐照(辐照)对免疫抑制大鼠体液免疫功能的调整作用。取大鼠54只随机分为三组:甲组各鼠腹腔注射环磷酰胺(CY,75mg/kg)和伤寒沙门氏菌鞭毛抗原(HAg,7×10~8菌体/只),同时各鼠每天全身辐照1h,共4周;乙组腹腔注射CY和HAg丙组仅腹腔注射HAg。结果甲、乙、丙三组于第四周末的存活率分别为83.3%、38.1%和66.7%(甲与乙组比较P<0.05);第四周末血清总IgG含量分别为141.4±17.6U/ml,120.3±16.6U/ml和117.0±22.9U/ml(甲组与其它两组比较P<0.01);第二周末抗H抗体效价分别为1:91.9、1:46.6和1:149.3(甲与乙组比较P<0.05;乙与丙组比较P<0.01)。结果表明,辐照对免疫功能低下的机体有增强免疫功能的作用。 相似文献
62.
SUMMARY In vivo extracellular recordings of 102 units in the central nucleus of the inferior colliculus (IC), were made in chronically implanted guinea-pigs during the sleep/wake cycle. During wakefulness, the units were classified according to their response characteristics. Most neurons (63%) recorded showed changes, increasing or decreasing in the number of evoked discharges during the animal's transitions between wakefulness and slow-wave sleep. In the paradoxical sleep phase, the result was similar; changes were observed in most neurons, while only 11% of units did not shift their discharge pattern during ipsilateral sound stimulation.
The post-stimulus time histogram of the overall evoked pattern of discharge showed sleep/wake dependency, i.e. changed in 35% of the units recorded during the 50 ms of sound stimulation.
Fifty-five percent of auditory neurons did not show any change in the spontaneous firing rate during slow-wave sleep as compared to the previous waking period, while 22% exhibited a discharge increase and 23% decreased their firing. During paradoxical sleep, 14 out of 17 cells increased their spontaneous firing rate. The IC auditory neurons send descending connections to regions such as the dorsal pontine nuclei, known to mediate sleep processes. Thus, for constant auditory input, the firing rate or number of discharge variations are due to functional shifts in the sleeping brain. Auditory processing is present during sleep and differs from that observed during wakefulness. Differences were observed in the evoked firing number and/or spontaneous rate, as well as in the pattern of discharge. The ultimate reason for auditory unit shifts during sleep remains yet unexplained. 相似文献
The post-stimulus time histogram of the overall evoked pattern of discharge showed sleep/wake dependency, i.e. changed in 35% of the units recorded during the 50 ms of sound stimulation.
Fifty-five percent of auditory neurons did not show any change in the spontaneous firing rate during slow-wave sleep as compared to the previous waking period, while 22% exhibited a discharge increase and 23% decreased their firing. During paradoxical sleep, 14 out of 17 cells increased their spontaneous firing rate. The IC auditory neurons send descending connections to regions such as the dorsal pontine nuclei, known to mediate sleep processes. Thus, for constant auditory input, the firing rate or number of discharge variations are due to functional shifts in the sleeping brain. Auditory processing is present during sleep and differs from that observed during wakefulness. Differences were observed in the evoked firing number and/or spontaneous rate, as well as in the pattern of discharge. The ultimate reason for auditory unit shifts during sleep remains yet unexplained. 相似文献
63.
V. S. Gurfinkel Yu. S. Levik 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1993,95(2):359-364
Horizontal eye movements were recorded in eight healthy subjects during super-slow trunk rotation with respect to the space-stationary head. In some trials, subjects simultaneously indicated their perception of selfmotion by means of a joystick. Over the frequency range employed (0.007–0.05 cycles per second, ±20°), all subjects perceived the relative motion of head and trunk as a head rotation with respect to the stationary trunk. Eye movements were observed which were in phase with imaginary head rotation; their amplitude exceeded the amplitude of actual body rotation. The grasping of a rigid ground-based handle (1) produced a sensation of trunk rotation in space, (2) suppressed the sensation of imaginary head rotation in space and (3) gave rise to a significant decrease in amplitude of eye movements. The grasping of a stiff rod with non-zero compliance did not produce these effects. It is concluded that eye movements in response to body rotation with respect to the fixed head are not purely reflex reactions, but are influenced by the internal representation of body motion. 相似文献
64.
Schwaninger A Lobmaier JS Fischer MH 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2005,167(1):49-55
When faces are turned upside-down they are much more difficult to recognize than other objects. This "face inversion effect" has often been explained in terms of configural processing, which is impaired when faces are rotated away from the upright. Here we report a "gaze inversion effect" and discuss whether it is related to configural face processing of the whole face. Observers reported the gaze locations of photographed upright or inverted faces. When whole faces were presented, we found an inversion effect both for constant errors and observer sensitivity. These results were closely replicated when only the eyes were visible. Together, our findings suggest that gaze processing is largely based on component-based information from the eye region. Processing this information is orientation-sensitive and does not seem to rely on configural processing of the whole face. 相似文献
65.
原因信息系统与医保系统实现有效接口,促进了药品的数量管理和医生工作站的推广,降低了错误处方的发生率,使医院服务更加顺畅。 相似文献
66.
大鼠三叉神经脊束间质核内接受内脏伤害性信息的含CB神经元向孤束核的投射 总被引:5,自引:0,他引:5
目的 探讨大鼠三叉神经脊束间质核(INV)内接受内脏伤害性信息的含calbindin D-28K(CB)神经元与孤束核(NTS)的投射联系。方法 用福尔马林刺激上消化道,应用荧光金(FG)逆行束路追踪结合Fos和CB的免疫荧光组织化学三重标记法。结果 INV的背侧边缘旁核(PaMd)和三叉旁核(PaV)内可见到大量FG逆标细胞,以注射FG的同侧为主。大部分FG逆标细胞(约71.2%)为CB免疫反应阳性。部分FG和CB双标记神经元(约31.5%)同时呈Fos免疫反应阳性的三重标记。结论 INV内部分接受内脏伤害性刺激的CB神经元可直接投射至NTS,含CB的神经元在内脏伤害性信息经INV向NTS的传导通路中,可能发挥重要作用. 相似文献
67.
68.
69.
Classes of neurons in relation to the laminar organization of the lateral geniculate nucleus in the tree shrew, Tupaia belangeri 总被引:1,自引:0,他引:1
We used the rapid Golgi and horseradish peroxidase (HRP) techniques to study the dendritic spread of relay neurons in functionally distinct laminae of the tree shrew dorsal lateral geniculate nucleus (LGNd). On the basis of their dendritic spread in relation to laminar and interlaminar zones, we describe three classes of relay neurons. Unilaminar neurons with multipolar radiate, bitufted, and intermediate types of dendrites. Dendrites of these neurons are confined to one lamina only, but also can have some of their segments in adjacent interlaminar zones. Multilaminar neurons with multipolar radiate, bitufted, and intermediate types of dendrites. Independent of the site of their cell bodies in a laminar or interlaminar zone, these neurons spread their dendrites over two or more laminae. Interlaminar neurons whose cell bodies and dendrites are confined to a single interlaminar zone. Unilaminar neurons are found in all the laminae. In the medial three laminae, they are more of the radiate type, whereas in laminae 4 and 5 their dendrites tend to be more of a tufted nature. Lamina 6 shows a preponderance of the elongated bitufted type. Multilaminar neurons, although less common as compared to the unilaminar, are also observed in all the laminae. Some neurons have their dendrites confined to an interlaminar zone. By retrograde transport of HRP injected into the visual cortex, we have shown that these neurons are, in fact, relay neurons. In addition to relay neurons, there are small interneurons with "axoniform" dendrites and an unmyelinated axon whose arborization is confined within the limits of the neuron's dendritic spread. Neurons of this type are not labeled with HRP injected into the visual cortex. We conclude that although each lamina is functionally specialized by input from ipsilateral or contralateral retina and by segregation of neurons responding to on or off stimuli, some multilaminar neurons can be found in each lamina. Thus, laminar as well as interlaminar zones contain a class of neurons that could provide a cross-talk between the functionally specialized laminae. Most relay neurons in all the laminae, however, confine their dendrites to their home lamina. Thus, the dendritic architecture of relay neurons allows for processing of information both within channels and between channels. 相似文献
70.
【目的】在信息交流视角下,探讨我国科技期刊知识服务转型发展的突破路径。 【方法】通过文献调研和对比分析法,探讨面向科技期刊知识服务的科学信息交流模式框架,对国内外科技期刊知识服务模式进行分析。 【结果】分别从正式交流和非正式交流视角,归纳总结国内外科技期刊所开展的知识服务。通过对比国内外科技期刊在服务模式、手段和渠道的差异,提出我国科技期刊知识服务的发展策略。 【结论】我国科技期刊应从集团化经营模式、自动化出版流程、基于微信矩阵拓展服务项目等方面入手,完善自身的知识服务体系,实现知识生产向知识服务的创新转型。 相似文献