全文获取类型
收费全文 | 11614篇 |
免费 | 592篇 |
国内免费 | 97篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 210篇 |
妇产科学 | 112篇 |
基础医学 | 1290篇 |
口腔科学 | 201篇 |
临床医学 | 631篇 |
内科学 | 3231篇 |
皮肤病学 | 237篇 |
神经病学 | 828篇 |
特种医学 | 390篇 |
外科学 | 2533篇 |
综合类 | 75篇 |
预防医学 | 250篇 |
眼科学 | 150篇 |
药学 | 586篇 |
中国医学 | 30篇 |
肿瘤学 | 1442篇 |
出版年
2023年 | 99篇 |
2022年 | 195篇 |
2021年 | 321篇 |
2020年 | 148篇 |
2019年 | 219篇 |
2018年 | 259篇 |
2017年 | 241篇 |
2016年 | 284篇 |
2015年 | 302篇 |
2014年 | 415篇 |
2013年 | 453篇 |
2012年 | 822篇 |
2011年 | 853篇 |
2010年 | 454篇 |
2009年 | 418篇 |
2008年 | 711篇 |
2007年 | 765篇 |
2006年 | 798篇 |
2005年 | 762篇 |
2004年 | 781篇 |
2003年 | 731篇 |
2002年 | 727篇 |
2001年 | 147篇 |
2000年 | 97篇 |
1999年 | 163篇 |
1998年 | 155篇 |
1997年 | 120篇 |
1996年 | 110篇 |
1995年 | 84篇 |
1994年 | 82篇 |
1993年 | 92篇 |
1992年 | 59篇 |
1991年 | 55篇 |
1990年 | 55篇 |
1989年 | 47篇 |
1988年 | 43篇 |
1987年 | 28篇 |
1986年 | 31篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 16篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1972年 | 5篇 |
1966年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
81.
We here report a molecular basis for downregulation of interferon (IFN)-beta production by V and C proteins of Sendai virus (SeV). The infection of HeLa cells with SeV poorly induced IFN-beta even if the expression of C/C' was disrupted. In contrast, when the expression of C/C'/Y1/Y2 or V/W was disrupted, SeV infection strongly induced IFN-beta production and significantly activated the interferon regulatory factor (IRF)-3 pathway. The independent expression of C or V inhibited the double-stranded (ds) RNA- or Newcastle disease virus (NDV)-induced activation of IRF-3 and NF-kappa B, as well as the IFN-beta promoter. This inhibitory effect was also observed when Y1, Y2, or a C-terminal half fragment (aa 85-204) of C was independently expressed. Phosphorylation and homodimer formation of IRF-3 were suppressed not only in cells infected with SeV capable of expressing both C/C'/Y1/Y2 (or Y1/Y2) and V/W, but also in HeLa cells constitutively expressing Y1. These results suggest that C, Y1, Y2, and V block signaling pathways leading to IRF-3 activation to downregulate IFN-beta production. 相似文献
82.
Comparison of the inhibitory effects of glucocorticoids on the expression of eotaxin in airway epithelial cell line BEAS-2B] 总被引:2,自引:0,他引:2
Koushi Ieki Satoshi Matsukura Fumio Kokubu Masatsugu Kurokawa Mio Kawaguchi Hideki Kuga Shin Watanabe Shintaro Suzuki Miho Odaka Hiroko Takeuchi Robert P Schleimer Mitsuru Adachi 《Arerugī》2004,53(4):423-429
OBJECTIVE: Inhaled corticosteroids play a pivotal role in the treatment of asthma. To observe the mechanisms of glucocorticoids, we focused our study on the comparison of several glucocorticoids' effects on eotaxin expression in the airway epithelial cells. METHODS: Airway epithelial cell line BEAS-2B was cultured in vitro. Cells were preincubated with or without glucocorticoids (becromethasone dipropionate; BDP, budesonide; BUD, fluticasone propionate; FP) and stimulated with TNFalpha and/or IL-4. Protein levels of eotaxin in the supernatants of the cultured cells were determined by ELISA. RESULTS AND CONCLUSIONS: TNFalpha and IL-4 increased the levels of eotaxin in BEAS-2B cells. Combination of these cytokines synergistically upregulated the eotaxin expression as reported previously. Each glucocorticoid significantly inhibited the expression of eotaxin protein induced with TNFalpha and IL-4 and the compared efficacy was in order of FP>BUD>BDP. FP seemed most potent and the inhibitory effect was also observed with relatively low concentration such as 10 (-10)M. Taken together, the comparison of the potency of each glucocorticoid using airway epithelial cells may reflect the efficacy of these drugs in asthmatics. 相似文献
83.
Intracerebroventricular administration of NPY stimulates resistin gene expression in mice 总被引:5,自引:0,他引:5
Yuzuriha H Inui A Goto K Asakawa A Fujimiya M Kasuga M 《International journal of molecular medicine》2003,11(5):675-676
Resistin is thought to cause insulin resistance and link obesity to type 2 diabetes mellitus. However, little is known about the effects of neuropeptide Y (NPY) on resistin gene expression in white adipose tissue (WAT). Resistin gene expression was determined by northern blot analysis in food-deprived mice after NPY administration. Administered NPY (1 nmol/mouse) significantly increased resistin mRNA expression in WAT by 72% compared with artificial cerebrospinal fluid treated controls. These observations indicate that NPY might have a role in regulating resistin gene expression in WAT and that the novel brain-fat axis might be involved in the pathogenesis of obesity and related diseases. 相似文献
84.
The effect of electro-acupuncture stimulation (EAS) on duodenal motility was examined in anesthetized, artificially ventilated rats. EAS was applied to the abdominal area or to a hindpaw for 30 s at stimulus intensities of 0.1-10.0 mA with a stimulus frequency of 20 Hz. The duodenal motility was measured using the balloon method at a position about 1.5 cm caudal from the pylorus. Duodenal motility was inhibited by EAS at intensities of more than 5.0 mA (suprathreshold of group IV afferent excitation) when applied to the abdominal area. The duodenal inhibitory response existed after bilateral vagotomy or spinal transection, but was abolished by sectioning bilateral splanchnic nerves. Duodenal motility was facilitated by EAS at intensities of more than 2.0 mA (subthreshold of group IV, and suprathreshold for groups II+III afferent excitation) when applied to a hindpaw. The duodenal facilitatory response by EAS to a hindpaw existed after sectioning the splanchnic nerves, but disappeared after bilateral vagotomy or spinal transection. Furthermore, repetitive electrical stimulation of vagal efferent nerves enhanced duodenal motility, while repetitive electrical stimulation of the splanchnic efferent nerves inhibited the motility. It was concluded that the inhibitory response of duodenal motility elicited by EAS to the abdominal area is a spinal reflex response involving splanchnic inhibitory efferent nerves, and the enhanced response of duodenal motility by EAS to a hindpaw is a supraspinal reflex response involving vagal excitatory nerves. 相似文献
85.
Yamamoto Y Tanaka H Yamazaki K Shirakawa S 《Shinrigaku kenkyu : The Japanese journal of psychology》2003,74(2):140-147
In this study, we developed a ratings scale for estimating sleep onset that would be capable of providing quantitative evaluations of the quality of the sleep onset process. We also examined factors affecting sleep onset using a questionnaire consisting of two separate clusters of items: the first, consisting of 9 items, related to the quality of sleep onset; and the second, consisting of 56 items, related to factors with apparent effects on sleep onset. The questionnaire was administered to 515 day-workers (range: 25-44 years old) for standardization. Each item was weighted based on the distribution of subject responses to determine discrimination. The reliability coefficient alpha for the questionnaire was high, exceeding 0.8. Of 41 items set out as potential factors affecting sleep onset, the results of the questionnaire indicated that five factors consisting of 26 items could be isolated as most likely affecting sleep onset. Path analysis indicated that sleep onset is more commonly affected by factors present at bedtime than factors related to sleep quality the previous night, or to daytime activities. 相似文献
86.
Blood supply to the retina and the lens in the gerbil (<Emphasis Type="Italic">Meriones unguiculatus</Emphasis>) 总被引:1,自引:0,他引:1
Imada H Isomura G Miyachi E 《Anatomical science international / Japanese Association of Anatomists》2003,78(1):36-41
The blood supply to the retina and the lens in 32 gerbils (Meriones unguiculatus) of both sexes from infancy to maturity was studied under light and stereoscopic microscopes, and a scanning electron microscope.
Mercox (CL-2R; Dai Nippon Ink, Tokyo, Japan) was injected into the left ventricle of 30 animals in order to visualize the
blood supply to the retina and the lens from the ophthalmic artery. The central retinal artery arises from the ophthalmic
artery, passes through the papilla of the optic nerve together with the central retinal vein and penetrates the vitreous space
(cavity of the eye) between the lens and the internal limiting membrane of the retina, where it divides into the central branches
covering the lens and the parietal branches to supply the retina. The former passes through the hyaloid space after branching
several arterioles and then covers the lens like a network from its medial and marginal sides. Different from small experimental
animals, the parietal branches, just after separating from the central one, divides into the nasal, dorsal and temporal branches
in the vitreous space, each of which then subdivides to distribute across the retina on the inner limiting membrane, then
delineates the membrana vasculosa retinae. This basal pattern of vasculization 1 day after birth continues to death. Both
the central and parietal branches of the central retinal artery correspond to the branches of the hyaloid artery in embryo
and the latter is preserved in adult gerbils. 相似文献
87.
Giant mitochondria in alcoholic liver disease 总被引:1,自引:0,他引:1
88.
Chung-Chuan Chou Shengmei Zhou Hideki Hayashi Motoki Nihei Yen-Bin Liu Ming-Shien Wen San-Jou Yeh Michael C. Fishbein James N. Weiss Shien-Fong Lin Delon Wu Peng-Sheng Chen 《The Journal of physiology》2007,580(3):895-906
We hypothesize that remodelling of action potential and intracellular calcium (Cai ) dynamics in the peri-infarct zone contributes to ventricular arrhythmogenesis in the postmyocardial infarction setting. To test this hypothesis, we performed simultaneous optical mapping of Cai and membrane potential ( V m ) in the left ventricle in 15 rabbit hearts with myocardial infarction for 1 week. Ventricular premature beats frequently originated from the peri-infarct zone, and 37% showed elevation of Cai prior to V m depolarization, suggesting reverse excitation–contraction coupling as their aetiology. During electrically induced ventricular fibrillation, the highest dominant frequency was in the peri-infarct zone in 61 of 70 episodes. The site of highest dominant frequency had steeper action potential duration restitution and was more susceptible to pacing-induced Cai alternans than sites remote from infarct. Wavebreaks during ventricular fibrillation tended to occur at sites of persistently elevated Cai . Infusion of propranolol flattened action potential duration restitution, reduced wavebreaks and converted ventricular fibrillation to ventricular tachycardia. We conclude that in the subacute phase of myocardial infarction, the peri-infarct zone exhibits regions with steep action potential duration restitution slope and unstable Cai dynamics. These changes may promote ventricular extrasystoles and increase the incidence of wavebreaks during ventricular fibrillation. Whereas increased tissue heterogeneity after subacute myocardial infarction creates a highly arrhythmogenic substrate, dynamic action potential and Cai cycling remodelling also contribute to the initiation and maintenance of ventricular fibrillation in this setting. 相似文献
89.
Hozumi Katsuto; Kondo Motonari; Nozaki Hideki; Kobori Akiko; Nishimura Takashi; Nishikawa Shin-Ichi; Sugamura Kazuo; Habu Sonoko 《International immunology》1994,6(9):1451-1454
The effects of IL-7 on the growth and differentiation of thymocyteswere analyzed using murine fetal thymua organ cultures (FTOC)in the presence of mAbs specific for the conventional IL-7 receptor(1L-7R) and for the common (c) chain. In FTOC, the developmentof CD4–CD8– double-negative thymocytes to CD4+CD8+double-positive (DP) and CD4+ or CD8+ single-positive (SP) cellswas not completely blocked by adding these mAbs, although cellgrowth was reduced by the treatment. To define a developingstage sensitive to the mAbs, most immature thymocytes, Pgp-1+c-kit cells, were cultured in the 2-deoxyguartosine treatedfetal thymus. In the presence of both mAbs in the culture, neitherDP nor SP thymocytes developed whereas either of the mAbs partiallyblocked their development. These results indicate that the Cchain is involved in early T cell development as an indispensablesubunlt of the functional IL-7 receptor complex. 相似文献
90.
Methyl-3,3,3-trifluoropropylsiloxane (F)-dimethylsiloxane (D) random and block copolymers were prepared. The random copolymers were prepared by equilibrium copolymerization starting from a mixture of cyclic F and D siloxanes with potassium silanolate as the catalyst. The F-D block copolymer was prepared by sequential anionic living polymerization of strained cyclic trisiloxanes using butyllithium as initiator, first polymerizing D3 then adding F3 after consumption of D3. The copolymer microstructure was established by means of 29Si NMR, differential scanning calorimetry (DSC), and gel-permeation chromatography (GPC). Characteristic glass transition temperature (Tg) shifts were observed depending on the F:D ratio of the random copolymers. It was demonstrated that the tensile strength of the poly(methyl-3,3,3-trifluoropropylsiloxane)-poly(dimethylsiloxane) (PTFPMS-PDMS) blend system was improved when either of the copolymers was added. 相似文献