全文获取类型
收费全文 | 3028篇 |
免费 | 62篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 3篇 |
妇产科学 | 7篇 |
基础医学 | 573篇 |
口腔科学 | 1篇 |
临床医学 | 112篇 |
内科学 | 158篇 |
皮肤病学 | 1篇 |
神经病学 | 1020篇 |
特种医学 | 36篇 |
外科学 | 257篇 |
综合类 | 269篇 |
预防医学 | 25篇 |
眼科学 | 10篇 |
药学 | 586篇 |
1篇 | |
中国医学 | 44篇 |
肿瘤学 | 18篇 |
出版年
2023年 | 16篇 |
2022年 | 26篇 |
2021年 | 36篇 |
2020年 | 41篇 |
2019年 | 38篇 |
2018年 | 29篇 |
2017年 | 38篇 |
2016年 | 41篇 |
2015年 | 49篇 |
2014年 | 76篇 |
2013年 | 113篇 |
2012年 | 100篇 |
2011年 | 129篇 |
2010年 | 101篇 |
2009年 | 117篇 |
2008年 | 131篇 |
2007年 | 93篇 |
2006年 | 128篇 |
2005年 | 83篇 |
2004年 | 82篇 |
2003年 | 103篇 |
2002年 | 87篇 |
2001年 | 74篇 |
2000年 | 79篇 |
1999年 | 80篇 |
1998年 | 95篇 |
1997年 | 94篇 |
1996年 | 72篇 |
1995年 | 76篇 |
1994年 | 86篇 |
1993年 | 79篇 |
1992年 | 71篇 |
1991年 | 87篇 |
1990年 | 66篇 |
1989年 | 62篇 |
1988年 | 54篇 |
1987年 | 68篇 |
1986年 | 52篇 |
1985年 | 51篇 |
1984年 | 41篇 |
1983年 | 27篇 |
1982年 | 35篇 |
1981年 | 17篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1976年 | 21篇 |
1975年 | 14篇 |
1974年 | 10篇 |
1972年 | 8篇 |
排序方式: 共有3147条查询结果,搜索用时 15 毫秒
21.
中缝大核内催产素在大鼠痛行为调制中的作用 总被引:5,自引:1,他引:4
目的:探讨中缝大核(NRM)内催产素(OT)在痛行为调制中的作用,及其和内源性5-HT在痛行为调制中的关系。方法:以钾离子透入法引起大鼠甩尾反应的电流强度(mA)为痛行为反应指标,测定动物痛阈,观察NRM内催产素对大鼠痛行为反应的影响。结果:NMR内注入催产素后,大鼠的痛阈明显增加;注入抗催产素血清后,大鼠的痛阈则明显降低。NRM内注入噻庚啶后,可阻断OT镇痛的效应。结论:NRM内的催产素在痛行为调制的复杂过程中发挥着一定作用,且其效应可能是通过内源性5-HT系统中介的。 相似文献
22.
用免疫细胞化学PAP法研究了5-羟色胺(5-HT)、P物质(SP)、亮氨酸脑啡肽(L-ENK)和神经肽Y(NPY)阳性神经元在大鼠旁巨细胞外侧核(PGCL)的分布。结果表明:5-HT、SP和L-ENK阳性细胞较多,从PGCL的吻端至尾端呈柱状分布,5-HT阳性细胞较靠近延髓腹侧表面和内侧,SP和LENK阳性细胞分布的范围较广,靠近外侧;NPY阳性细胞较少,多集中在PGCL的尾侧至中分的区域。 相似文献
23.
Dusica Maysinger Mario Herrera-Marschitz Michel Goiny Urban Ungerstedt A. Claudio Cuello 《Brain research》1992,577(2):300-305
The effects of intraventricular nerve growth factor (NGF) or saline treatments on extracellular acetylcholine (ACh), dopamine (DA) and adenosine (Ade) levels in the cortex and striatum of rats with unilateral devascularizing cortical lesions were studied in vivo with microdialysis. The devascularizing cortical lesion produced a decrease in extracellular ACh levels in both cortex and striatum as compared to those in normal rats, while the NGF treatment produced a significant increase in ACh levels in both regions. NGF could even increase cortical ACh levels in normal rats. The cortical lesion produced a decrease in extracellular DA in the cortex, while the NGF treatment appeared to reverse this effect. No significant changes in DA were observed in the striatum. The present study gives evidence that a unilateral cortical devascularizing lesion leads to changes in extracellular ACh and DA levels in cortex and striatum and that these changes could be reversed with intraventricular NGF treatment. 相似文献
24.
伏隔核毁损对MAP模型大鼠行为及脑内DA受体影响的研究 总被引:2,自引:1,他引:1
目的探讨立体定向伏隔核毁损对甲基苯丙胺(MAP)模型大鼠行为学及不同脑区多巴胺D2受体表达的影响。方法80只SpraqueDawley(SD)大鼠随即分为对照组、模型组、假手术组和手术组,每组各20只;采用经腹腔注射MAP制备精神分裂症模型,立体定向-直流电毁损伏隔核,观察大鼠刻板行为变化,原位杂交法观察额叶、颞叶、边缘区及脑干部位D2受体表达。结果与对照组比较,模型组及假手术组大鼠刻板行为评分及各个脑区D2受体表达均显著增加;而与模型组及假手术组比较,手术组大鼠刻板行为评分及各脑区DA受体阳性细胞数目均显著减少。结论伏隔核毁损可能是通过抑制使用MAP而诱发的脑内D2表达的亢进而改变其行为学的异常。 相似文献
25.
The present study investigated the specific ways by which cytotoxicity due to glutamate receptor stimulation could be attenuated by the administration of agonists and antagonists of the ionotropic and metabotropic glutamate receptors within the nucleus basalis magnocellularis (NBM) of rats as measured by cortical choline acetyltransferase activity. The results of these studies suggest that (1) the cytotoxicity of ibotenate to NBM cholinergic cells is not dependent upon stimulation of metabotropic glutamate receptors, but results from activation of
(NMDA) receptors, (2) the cytotoxicity of quisqualate to cholinergic cells within the NBM is not dependent upon stimulation of NMDA or metabotropic receptors, and (3) the cytotoxicity of NMDA was prevented by administration (i.p.) of the un-competitive NMDA antagonist memantine (30 mg/kg), resulting in plasma levels of 2.5 μg/ml, a concentration known to block efficiently NMDA receptors in vitro. Finally, performance of a food-motivated, delayed-alternation task on a T-maze was impaired by injections of NMDA into the NBM, but was prevented by co-administration of NMDA with memantine. 相似文献
26.
F lix F. Cruz-Sanchez Marco L. Rossi Adriana Cardozo Ana Picardo E. Tolosa 《Journal of the neurological sciences》1992,110(1-2):228-231
The grumose degeneration observed in the dentate nuclei of 7 cases of progressive supranuclear palsy (PSP) was studied with a panel of antibodies which included 2 neurofilaments, Tau and ubiquitin. Dentate nucleus neurons were negative with all antibodies except ubiquitin which showed a slightly positive homogeneous pattern of staining. The amorphous material surrounding swollen or normal neurons was strongly positive for neurofilament and subunits and numerous torpedoes were observed in the granular layer of the cerebellar cortex. Our results confirm that grumose degeneration consists in degeneration of terminal axons of Purkinje cells in the dentate nucleus. The positivity of dentate nucleus neurons for ubiquitin may support the concept of synaptic dysfunction between Purkinje cells and dentate nucleus neurons. 相似文献
27.
Anatomical studies have revealed the existence of an ascending pathway originating in the spinal cord and medullary dorsal horn, relaying in nucleus submedius (Sm) in medial thalamus and terminating in ventrolateral orbital cortex. It has been suggested that this pathway may be involved in the transmission of nociceptive information. In the present study extracellular recordings were obtained from neurons in Sm of anesthetized arthritic and normal rats. Mechanical and thermal stimuli were delivered to various regions of the body to determine the types of somatic stimuli which could activate Sm neurons. Over 40% of the 146 neurons studied responded to somatic stimuli. In the normal rats only high intensity mechanical and thermal stimuli were effective in inducing responses. In the arthritic rats lower intensity mechanical stimuli, joint movements and high intensity thermal stimuli were effective. Such stimuli produce nociceptive reactions in the freely moving arthritic rat. Almost all the responses were excitatory and generally lasted the entire duration of the 15-s stimuli employed. In some cases after-discharges were present. The receptive fields of the neurons were in almost all cases large and bilateral. These findings support the hypothesis that Sm may be involved in mediating the affective-motivational aspects of pain. 相似文献
28.
29.
快乐作为情绪的重要方面,对人类的生存具有重要意义。早期关于快乐脑机制的研究将大脑奖励系统误认为是产生快乐的快乐中心,认为多巴胺是将感觉刺激转化为快乐的神经递质。最新的研究指出,产生快乐的脑环路主要包括伏核壳、脑干臂旁核和腹侧苍白球。 相似文献
30.
Masami Yoshida Hideyasu Yokoo Kimihiro Nakahara Masaru Tomita Naoyuki Hamada Michiko Ishikawa Jyunko Hatakeyama Masatoshi Tanaka Ikuko Nagatsu 《Brain research》1997,767(2):87
Infusion of muscimol (5×10−5 M, 60 min) into the nucleus accumbens (NAC) through a dialysis membrane caused a significant increase in extracellular dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC). Fos-like immunoreactivity induced by intra-NAC infusion of muscimol was seen ipsilaterally in many accumbofugal target areas, but no Fos-positive neurons were seen in the vicinity of the dialysis membrane in the NAC. Sequential staining of Fos and tyrosine hydroxylase (TH) immunoreactivities revealed that a portion of A10 dopaminergic neurons were double-labelled. These results suggest that muscimol in the NAC disinhibits mesolimbic DA neuronal activity possibly through activity of the accumbofugal GABA neuron system. 相似文献