全文获取类型
收费全文 | 3359483篇 |
免费 | 272940篇 |
国内免费 | 13627篇 |
专业分类
耳鼻咽喉 | 46271篇 |
儿科学 | 106548篇 |
妇产科学 | 85540篇 |
基础医学 | 538848篇 |
口腔科学 | 91263篇 |
临床医学 | 302270篇 |
内科学 | 584717篇 |
皮肤病学 | 91406篇 |
神经病学 | 281144篇 |
特种医学 | 130487篇 |
外国民族医学 | 159篇 |
外科学 | 522490篇 |
综合类 | 100142篇 |
现状与发展 | 23篇 |
一般理论 | 2203篇 |
预防医学 | 283314篇 |
眼科学 | 78130篇 |
药学 | 230519篇 |
23篇 | |
中国医学 | 10389篇 |
肿瘤学 | 160164篇 |
出版年
2021年 | 55012篇 |
2020年 | 35136篇 |
2019年 | 58099篇 |
2018年 | 71143篇 |
2017年 | 54226篇 |
2016年 | 59593篇 |
2015年 | 73974篇 |
2014年 | 108121篇 |
2013年 | 173124篇 |
2012年 | 88162篇 |
2011年 | 88381篇 |
2010年 | 116320篇 |
2009年 | 120376篇 |
2008年 | 75793篇 |
2007年 | 78610篇 |
2006年 | 89298篇 |
2005年 | 84359篇 |
2004年 | 86621篇 |
2003年 | 77351篇 |
2002年 | 67643篇 |
2001年 | 103419篇 |
2000年 | 96342篇 |
1999年 | 95665篇 |
1998年 | 64982篇 |
1997年 | 62490篇 |
1996年 | 60402篇 |
1995年 | 55811篇 |
1994年 | 49962篇 |
1993年 | 46595篇 |
1992年 | 65720篇 |
1991年 | 63886篇 |
1990年 | 60958篇 |
1989年 | 60755篇 |
1988年 | 56011篇 |
1987年 | 54816篇 |
1986年 | 52001篇 |
1985年 | 52149篇 |
1984年 | 47586篇 |
1983年 | 43517篇 |
1982年 | 41081篇 |
1981年 | 38865篇 |
1980年 | 36742篇 |
1979年 | 39549篇 |
1978年 | 35303篇 |
1977年 | 32240篇 |
1976年 | 29827篇 |
1975年 | 29324篇 |
1974年 | 30160篇 |
1973年 | 28752篇 |
1972年 | 27129篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
In 1983, 1623 primary and secondary schoolchildren took part in a health survey which was organized by the Busselton Population Studies Group. Age, sex, weight, height and country of birth were recorded for each child. Where possible, the country of birth of parents and the occupation of the father were extracted from previous Busselton surveys of adults. Compared with Perth schoolchildren, the difference in the attained weight and height of Busselton children at any age was small. This was so even though the two communities differ in location (rural compared with metropolitan), in ethnic origin (mainly British compared with diverse origins) and, probably, in social-rank distribution. Data from the two communities showed that a similar small secular increase in height had occurred since 1970/1971. This increase averaged at 1.2 cm for children at each year of age in Busselton and 1.5 cm to 1.6 cm for children in Perth. 相似文献
992.
993.
994.
Carnitine status in Reye and Reye-like syndromes 总被引:4,自引:0,他引:4
Fourteen children with the following Reye and Reye-like syndromes were studied to determine each patient's carnitine status: valproate-induced Reye-like attack, ornithine transcarbamylase deficiency, systemic carnitine deficiency, methylmalonic acidemia, and propionic acidemia. Reduced free carnitine and increased serum and urine acylcarnitine levels were found in all patients except for 2 with Reye syndrome, in whom serum creatinine levels were mildly elevated and serum free carnitine levels were not reduced. The renal free carnitine reabsorption rate was reduced in all cases. The free carnitine content of autopsied liver samples were reduced in 2 Reye syndrome patients, 2 OTC deficiency patients, and in a single systemic carnitine deficiency patient. The observed secondary free carnitine deficiency may be a factor in the pathogenesis of Reye and Reye-like syndromes. 相似文献
995.
A novel approach for modelling the biological activity of organic molecules, which requires simultaneous consideration of the influence of all factors (topological, steric, hydrophobic, and electronic) that determine the bioactivity, is used to study the interaction of a series of benzoates with anti-p-(p'-azophenylazo)benzoate antibody. The results obtained suggest that this biological interaction proceeds by a two-step stereospecific mechanism. The first step requires a geometrical correspondence between the benzoates and the cavity in the biomacromolecule, which enables the pharmacophore to come into close contact with the receptor. The second step is the orbitally controlled electronic interaction between the active parts of the benzoates and the antibody. The electronic interaction results from pi-charge transfer from the pharmacophore to the biomacromolecule and from the formation of pi-complexes. A proposed mathematical model for this biological interaction exhibits some statistical advantages over existing models. 相似文献
996.
The influence of food and water intake on mefenamic acid (N-2,3-xylylanthranilic acid) bioavailability from commercial capsules of high bioavailability was studied in four healthy male volunteers. The drug was administered as a single oral dose of 250 mg, under fasting or nonfasting conditions, and a 4 X 4 Latin-square design was used. Eight blood samples were collected over a 24-h period following drug administration, and the drug plasma concentrations were determined by HPLC. The bioavailability of mefenamic acid from capsules was markedly influenced in the fasting subjects by the water but not by the food intake. A good correlation was found between the bioavailability and amount of water ingested with the drug in the fasting subjects. The area under the plasma concentration-time curve (AUC0-infinity) of mefenamic acid was highest when the capsule was taken with 50 mL of water or immediately after a meal. Increasing the amount of water from 50 to 500 mL in the fasting subjects caused a significant reduction in AUC0-infinity. 相似文献
997.
998.
999.
1000.
Alpha-adrenoreceptor reagents. 4. Resolution of some potent selective prejunctional alpha 2-adrenoreceptor antagonists 总被引:1,自引:0,他引:1
A P Welbourn C B Chapleo A C Lane P L Myers A G Roach C F Smith M R Stillings I F Tulloch 《Journal of medicinal chemistry》1986,29(10):2000-2003
The resolution of three 2-substituted derivatives of idazoxan is described. The enantiomers show large separations in activity in a variety of in vitro and in vivo tests, and the active isomers are all potent and selective antagonists at the alpha 2-adrenoreceptor. The significance of these results in relation to those published on the enantiomers of idazoxan and to those on optically active alpha 2-adrenoreceptor agonists is discussed. 相似文献