全文获取类型
收费全文 | 55524篇 |
免费 | 4963篇 |
国内免费 | 3251篇 |
专业分类
耳鼻咽喉 | 855篇 |
儿科学 | 684篇 |
妇产科学 | 618篇 |
基础医学 | 7462篇 |
口腔科学 | 1068篇 |
临床医学 | 6690篇 |
内科学 | 9260篇 |
皮肤病学 | 820篇 |
神经病学 | 3304篇 |
特种医学 | 2757篇 |
外国民族医学 | 21篇 |
外科学 | 6051篇 |
综合类 | 6273篇 |
现状与发展 | 13篇 |
一般理论 | 5篇 |
预防医学 | 3217篇 |
眼科学 | 1304篇 |
药学 | 5702篇 |
38篇 | |
中国医学 | 2444篇 |
肿瘤学 | 5152篇 |
出版年
2024年 | 173篇 |
2023年 | 873篇 |
2022年 | 2152篇 |
2021年 | 3033篇 |
2020年 | 2190篇 |
2019年 | 2018篇 |
2018年 | 2052篇 |
2017年 | 1837篇 |
2016年 | 1837篇 |
2015年 | 2668篇 |
2014年 | 3080篇 |
2013年 | 3000篇 |
2012年 | 4290篇 |
2011年 | 4546篇 |
2010年 | 2808篇 |
2009年 | 2238篇 |
2008年 | 2975篇 |
2007年 | 2988篇 |
2006年 | 2713篇 |
2005年 | 2560篇 |
2004年 | 1879篇 |
2003年 | 1718篇 |
2002年 | 1433篇 |
2001年 | 1151篇 |
2000年 | 1129篇 |
1999年 | 1150篇 |
1998年 | 636篇 |
1997年 | 625篇 |
1996年 | 492篇 |
1995年 | 430篇 |
1994年 | 395篇 |
1993年 | 235篇 |
1992年 | 380篇 |
1991年 | 300篇 |
1990年 | 283篇 |
1989年 | 258篇 |
1988年 | 223篇 |
1987年 | 194篇 |
1986年 | 163篇 |
1985年 | 123篇 |
1984年 | 81篇 |
1983年 | 69篇 |
1982年 | 26篇 |
1981年 | 37篇 |
1980年 | 24篇 |
1979年 | 38篇 |
1978年 | 23篇 |
1977年 | 24篇 |
1976年 | 32篇 |
1974年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Endophthalmitis from Mycobacterium bovis-bacille Calmette-Guérin after intravesicular bacille Calmette-Guérin injections for bladder carcinoma 总被引:1,自引:0,他引:1
PURPOSE: To present clinical and histologic findings of intraocular infection with Mycobacterium bovis-bacille Calmette-Guérin after intravesicular bacille Calmette-Guérin injections for treatment of bladder carcinoma. METHODS: A 77-year-old man was initially seen with visual acuity of 20/200, focal retinitis, vasculitis, and progressive vitreous opacity in the right eye and visual acuity of light perception, intraocular inflammation, and a dense cataract in the left eye 14 months after intravesicular injection of live bacille Calmette-Guérin organisms. RESULTS: Vitreous cultures in the right eye demonstrated growth of bacille Calmette-Guérin organisms. Bilateral loss of light perception occurred despite systemic antimy-cobacterial therapy. Histopathologic examination demonstrated nongranulomatous inflammation and acid-fast bacilli in both eyes. CONCLUSION: Delayed endogenous endophthalmitis may develop after intravesicular bacille Calmette-Guérin injection that may not respond to systemic agents. Intravitreal therapy may be indicated. 相似文献
102.
When liriodendrin or syringin was incubated for 24 h with human intestinal bacteria, two metabolites, (+)-syringaresinol-beta-D-glucopyranoside and (+)-syringaresinol, from liriodendrin and one metabolite, synapyl alcohol, from syringin were produced. The metabolic time course of liriodendrin was as follows: at early time, liriodendrin was converted to (+)-syringaresinol-beta-D-glucopyranoside, and then (+)-syringaresinol. The in vitro cytotoxicities of these metabolites, (+)-syringaresinol and synapyl alcohol, were superior to those of liriodendrin and syringin. 相似文献
103.
Hak Cheol Kwon Byeong Gon Lee Seung Hee Kim Chil Mann Jung Sung Youl Hong Jeung Whan Han Hyang Woo Lee Ok Pyo Zee Kang Ro Lee 《Archives of pharmacal research》1999,22(4):410-413
In bioassay-guided search for inducible nitric oxide synthase (iNOS) inhibitory compounds from higher plants of South Korea, two beta-carboline alkaloids, 4-methoxy-1-vinyl-beta-carboline (1) and 4,8-dimethoxy-l-vinyl-beta-carboline (2) have been isolated from the cortex of Melia azedarach var. japonica. The structures of these compounds were elucidated on the basis of spectroscopic data. Compounds 1 and 2 showed marked inhibitory activity of iNOS on LPS- and interferon-gamma-stimulated RAW 264.7 cells. 相似文献
104.
Cytotoxicity of urushiols isolated from sap of Korean lacquer tree (Rhus vernicifera stokes) 总被引:1,自引:0,他引:1
Hong DH Han SB Lee CW Park SH Jeon YJ Kim MJ Kwak SS Kim HM 《Archives of pharmacal research》1999,22(6):638-641
Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells. 相似文献
105.
Socialization games, designed to reinforce prosocial behavior between moderately and severely mentally retarded aggressive institutionalized women, were presented to two groups on 12 occasions over 8 weeks, randomly interspersed with 12 sessions of arts and crafts or filmstrip stories. Half of the sessions were presented in the morning and half in the afternoon. Video-taped observations of interpersonal behavior for 10 minutes after each session were analyzed in terms of friendly, unfriendly, and inactive behavior, and the distance of each subject from each other subject was measured. The rate of friendly behavior was significantly greater after the games and was higher in morning than afternoon sessions. The games also significantly decreased interpersonal distance. Both unfriendly behavior and inactivity were higher after the "placebo" sessions. The relevance of these results to institutional programming was discussed. 相似文献
106.
To elucidate the nature of the apical opacity that is commonly seen in patients with tuberculosis--usually referred to as an "apical cap" or "apical pleural thickening"--18 patients with upper lobe tuberculosis were studied with high-resolution computed tomography (HRCT). All had a homogeneous apical opacity at least 1 cm thick on chest radiographs. Fifteen of the 18 had a history of pulmonary tuberculosis of more than 5 years duration, and nine showed evidence of ipsilateral pleurisy. HRCT scans at the apex of the thorax in all nine patients scanned at this level showed that extrapleural fat with interspersed vessels accounted for most of the plain radiographic opacity. Scans obtained at a level slightly above visible aerated lung showed extrapleural fat 3-25 mm thick peripherally and atelectatic lung centrally. At more caudal levels, at which both aerated lung and "thickened pleura" were visible on plain radiographs, HRCT showed extrapleural fat (3-20 mm thick), thickened pleura (1-3 mm thick), and atelectatic lung peripherally and areas of emphysematous bullae, bronchiectasis, and atelectatic lung centrally. 相似文献
107.
The extracts of sixty Korean plants were evaluated for their biological activities such as antitumor activities against Sarcoma 180, Leukemia SN-36 and Ehrlich ascites carcinoma, antimicrobial activities and behavioral observation in mice. The results are tabulated. 相似文献
108.
The inhibitory effect of the thoracic duct lymph of a patient with lung cancer on the "one-way" mixed lymphocyte reaction without cytoxicity is unequivocally demonstrated. The effect seems to be dose related. A moderate inhibition of mixed lymphocyte reaction is still observed, even if the responding cells are preincubated in the thoracic duct lymph for 1 hr only prior to the addition of stimulating cells. The inhibitory effect of thoracic duct lymph on the mixed lymphocyte reaction is no longer evident when the material is added 1-4 days after the beginning of culture. These observations suggest that the mechanism of the inhibitory effect of thoracic duct lymph may be a simple attachment of inhibitory factors to the receptor sites on the responding lymphocytes, causing interference in cell to cell interaction. The inhibitory effect of thoracic duct lymph collected 1 week after the thoracic duct drainage on mixed lymphocyte reaction is significantly lower than that of thoracic duct lymph collected at the beginning of the procedure. This indicates that the blocking effect of thoracic duct lymph can be easily removed by this technique; which is technically feasible in man. The interrelationship of the tumor-specific blocking factor, thoracic duct drainage, and tumor growth pattern are discussed with respect to the potential usefulness of this procedure as adjuvant immunotherapy in the management of patients with neoplastic diseases. 相似文献
109.
110.
BDNF blocks caspase-3 activation in neonatal hypoxia-ischemia 总被引:57,自引:0,他引:57
Han BH D'Costa A Back SA Parsadanian M Patel S Shah AR Gidday JM Srinivasan A Deshmukh M Holtzman DM 《Neurobiology of disease》2000,7(1):38-53
Hypoxic-ischemic (H-I) injury to the brain in the perinatal period often leads to significant long-term neurological deficits. In a model of neonatal H-I injury in postnatal day 7 rats, our previous data have shown that cell death with features of apoptosis is prominent between 6 and 24 h after H-I and that neurotrophins, particularly BDNF, can markedly protect against tissue loss. During brain development, caspase-3 is required for normal levels of programmed cell death. Utilizing an antibody specific for the activated form of caspase-3, CM1, we now show that caspase-3 is specifically activated in neuronal cell bodies and their processes beginning at 6 h and peaking 24 h following unilateral carotid ligation and exposure to hypoxia in postnatal day 7 rats. Caspase-3 activation began to occur in cortex at 6 h and in striatum and hippocampus at 12-18 h. Caspase-3 activation was also observed in developing oligodendrocytes. Intracerebroventricular injection of BDNF prior to H-I injury almost completely abolished evidence of H-I-induced caspase-3 activation in vivo. Utilizing a specific molecular marker of an apoptotic pathway, these findings demonstrate that H-I injury to the developing brain is a strong apoptotic stimulus leading to caspase-3 activation, that BDNF can block this process in vivo, and that the ability of BDNF to inhibit caspase activation and subsequent apoptosis likely accounts in large part for its protection against neuronal injury in this model. 相似文献