全文获取类型
收费全文 | 957757篇 |
免费 | 59663篇 |
国内免费 | 1073篇 |
专业分类
耳鼻咽喉 | 12619篇 |
儿科学 | 31633篇 |
妇产科学 | 25015篇 |
基础医学 | 157663篇 |
口腔科学 | 25275篇 |
临床医学 | 83772篇 |
内科学 | 176747篇 |
皮肤病学 | 22456篇 |
神经病学 | 66953篇 |
特种医学 | 35191篇 |
外国民族医学 | 116篇 |
外科学 | 142141篇 |
综合类 | 15681篇 |
现状与发展 | 2篇 |
一般理论 | 219篇 |
预防医学 | 71481篇 |
眼科学 | 22541篇 |
药学 | 74400篇 |
1篇 | |
中国医学 | 2015篇 |
肿瘤学 | 52572篇 |
出版年
2018年 | 9886篇 |
2016年 | 8251篇 |
2015年 | 9190篇 |
2014年 | 12419篇 |
2013年 | 18910篇 |
2012年 | 26675篇 |
2011年 | 29189篇 |
2010年 | 16991篇 |
2009年 | 15673篇 |
2008年 | 27420篇 |
2007年 | 29779篇 |
2006年 | 29591篇 |
2005年 | 28259篇 |
2004年 | 27599篇 |
2003年 | 26548篇 |
2002年 | 25840篇 |
2001年 | 43313篇 |
2000年 | 44770篇 |
1999年 | 36852篇 |
1998年 | 9963篇 |
1997年 | 8523篇 |
1996年 | 8833篇 |
1995年 | 8209篇 |
1994年 | 7509篇 |
1992年 | 27776篇 |
1991年 | 28980篇 |
1990年 | 29110篇 |
1989年 | 28276篇 |
1988年 | 25976篇 |
1987年 | 25738篇 |
1986年 | 24151篇 |
1985年 | 23124篇 |
1984年 | 17254篇 |
1983年 | 14694篇 |
1982年 | 8033篇 |
1981年 | 7343篇 |
1979年 | 16680篇 |
1978年 | 12001篇 |
1977年 | 9907篇 |
1976年 | 9962篇 |
1975年 | 11685篇 |
1974年 | 13499篇 |
1973年 | 12978篇 |
1972年 | 12205篇 |
1971年 | 11744篇 |
1970年 | 10932篇 |
1969年 | 10361篇 |
1968年 | 9782篇 |
1967年 | 8771篇 |
1966年 | 7829篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
V B Tuason 《The Journal of clinical psychiatry》1986,47(3):126-129
In a parallel groups, double-blind study, 54 acutely psychotic schizophrenics were given loxapine or haloperidol parenterally for 24 to 72 hours, then orally for a total study period of up to 10 days. Dosage ratios of loxapine to haloperidol ranged from a minimum of 2.7:1 to a maximum of 4.4:1. Both groups showed significant and rapid improvement from baseline. Forty-eight percent of the loxapine patients and 33% of the haloperidol patients achieved and maintained a global severity of illness rating of mild or better. By the end of the study, 84% of the loxapine patients and 63% of the haloperidol patients had achieved an improvement rating of moderate or marked. This difference approached significance (p less than .10). The most frequently reported adverse experiences were dystonic reactions and akathisia. The number and severity of adverse experiences did not differ significantly between drug groups. Intramuscular loxapine was at least as effective as haloperidol in the initial management of hostile and aggressive schizophrenic patients. The maintenance of therapeutic response after conversion to oral concentrate was comparable with the two drugs. 相似文献
992.
993.
1-Methyl-4-(2'-methylphenyl)-1,2,3,6-tetrahydropyridine (2'-CH3-MPTP) is a more potent dopaminergic neurotoxin than MPTP in mice 总被引:1,自引:0,他引:1
S K Youngster R C Duvoisin A Hess P K Sonsalla M V Kindt R E Heikkila 《European journal of pharmacology》1986,122(2):283-287
The administration to mice of 1-methyl-4-(2'-methylphenyl)-1,2,3, 6-tetrahydropyridine (2'-CH3-MPTP), a substituted analog of the dopaminergic neurotoxin MPTP caused even more dopaminergic toxicity than MPTP itself. Under conditions in which MPTP was relatively ineffective (i.e. two injections per day of 0.113 mmol/kg at an interval of 6 h for one or two days), 2'-CH3-MPTP caused a very large decrement in the neostriatal content of dopamine and its metabolites and a corresponding decrement in the capacity of a neostriatal synaptosomal preparation to take up [3H]dopamine. Moreover, 2'-CH3-MPTP administration (as few as four injections) caused a virtually complete loss of nerve cells in the zona compacta of the substantia nigra. This compound, like MPTP, may prove to be a valuable research tool. 相似文献
994.
In brain regions containing noradrenergic (NA) cell bodies or terminals, DSP-4 induces changes in the activity of catecholamine-synthesizing enzymes which suggest that central NA neurons are lesioned by this neurotoxin. In contrast, the lack of change in the same enzymatic activities in an area containing mostly adrenergic (A) neurons (C2 region), favors the hypothesis of a resistance of the A neurons to DSP-4. Furthermore, the enzymatic changes observed in peripheral organs suggest a peripheral activation of the NA cell bodies in response to lesioning of the sympathetic terminals by DSP-4. 相似文献
995.
996.
997.
998.
999.
M Gómez-Silva L Garza-Oca?as N Waksman V Rivas A Pi?eyro-López 《Toxicology in vitro》2005,19(1):47-53
T-514 (Peroxisomicine A(1)) from Karwinskia humboldtiana is a dimeric hydroxyanthracenone with a highly selective cytotoxic effect on tumor cells. We evaluated the metabolism of this compound in two in vitro systems (liver microsomes and hepatocytes) and assessed the cytotoxicity of its metabolites on normal and tumor cells. Microsomes (12.5, 125 and 250 microg of protein/ml) and hepatocytes (1 x 10(6) cells/ml) were incubated with the toxin (25 microM) for 0.5, 1, 3, 6, 9, 12 and 24 h and the samples were examined using chromatographic analysis and UV spectra. Two metabolites (M1 and M2) were detected in the rat microsomes and one (M1) in the monkey microsomes. The retention times and UV spectra of the peaks were very similar to those of the toxin T-514. M1 was isolated and identified as a mixture of two isomers. The cytotoxicity of the metabolites was evaluated in Chang liver and Hep G2 cells but they did not show the selective cytotoxic effect on tumor cells seen in the original compound. 相似文献
1000.