收费全文 | 198583篇 |
免费 | 2164篇 |
国内免费 | 164篇 |
耳鼻咽喉 | 1367篇 |
儿科学 | 6952篇 |
妇产科学 | 3198篇 |
基础医学 | 19208篇 |
口腔科学 | 2101篇 |
临床医学 | 13727篇 |
内科学 | 36549篇 |
皮肤病学 | 1916篇 |
神经病学 | 18529篇 |
特种医学 | 9789篇 |
外科学 | 32617篇 |
综合类 | 2441篇 |
预防医学 | 18608篇 |
眼科学 | 3042篇 |
药学 | 11408篇 |
中国医学 | 715篇 |
肿瘤学 | 18744篇 |
2023年 | 107篇 |
2022年 | 220篇 |
2021年 | 517篇 |
2020年 | 298篇 |
2019年 | 411篇 |
2018年 | 22356篇 |
2017年 | 17653篇 |
2016年 | 19944篇 |
2015年 | 1428篇 |
2014年 | 1457篇 |
2013年 | 1503篇 |
2012年 | 8097篇 |
2011年 | 22208篇 |
2010年 | 19475篇 |
2009年 | 12041篇 |
2008年 | 20536篇 |
2007年 | 22831篇 |
2006年 | 1718篇 |
2005年 | 3356篇 |
2004年 | 4573篇 |
2003年 | 5528篇 |
2002年 | 3645篇 |
2001年 | 936篇 |
2000年 | 1103篇 |
1999年 | 843篇 |
1998年 | 536篇 |
1997年 | 458篇 |
1996年 | 321篇 |
1995年 | 312篇 |
1994年 | 277篇 |
1993年 | 219篇 |
1992年 | 507篇 |
1991年 | 502篇 |
1990年 | 555篇 |
1989年 | 521篇 |
1988年 | 476篇 |
1987年 | 413篇 |
1986年 | 352篇 |
1985年 | 335篇 |
1984年 | 198篇 |
1983年 | 198篇 |
1982年 | 121篇 |
1980年 | 104篇 |
1979年 | 170篇 |
1978年 | 100篇 |
1977年 | 95篇 |
1974年 | 95篇 |
1973年 | 87篇 |
1970年 | 94篇 |
1969年 | 94篇 |
The common marmoset (Callithrix jacchus) is a useful experimental animal to evaluate the pharmacokinetics of drug candidates. Cytochrome P450 (P450) 2B enzyme in marmoset livers has been identified; however, only limited information on the enzymatic properties and distribution has been available.
Marmoset P450 2B6 amino acids showed high sequence identities (>86%) with those of primates including humans and cynomolgus monkeys. Phylogenetic analysis using amino acid sequences indicated that marmoset P450 2B6 was closer to human and cynomolgus monkey P450 2B6 than to P450 2B orthologs of other species, including pigs, dogs, rabbits and rodents.
Quantitative polymerase chain reaction analysis using specific primers showed P450 2B6 mRNA predominantly expressed in livers among the five marmoset tissues, similar to those of humans and cynomolgus monkeys.
Marmoset P450 2B6 heterologously expressed in Escherichia coli membranes oxidized 7-ethoxycoumarin, pentoxyresorufin, propofol and testosterone, at roughly similar rates to those of humans and/or cynomolgus monkeys. A high capacity of marmoset P450 2B6 with propofol 4-hydroxylation (at low ionic strength conditions) with a low Km value was relatively comparable to that for marmoset livers.
These results collectively indicated a high propofol 4-hydroxylation activity of P450 2B6 expressed in marmoset livers.
Purpose
Suppression of respiratory movement of the liver would be desirable for high-precision radiation therapy for liver tumors. We aimed to investigate the effect of our original device-free compressed shell fixation method and breathing instruction on suppression of respiratory movement. The characteristics of liver motion based on the movement of a fiducial marker were also analyzed.Methods and Materials
First, respiratory amplitudes of the liver with the device-free compressed shell were analyzed from the data of 146 patients. The effect of this shell fixing method on liver movement was evaluated. Second, as another cohort study with 166 patients, interfractional internal motion of the liver for patients fixed in the shell was calculated using the fiducial marker coordinate data of images for position setting before daily irradiation. Third, in another 12 patients, intrafractional internal motion was calculated from the fiducial marker coordinate data using x-ray images before and after irradiation.Results
The median respiratory movement without the shell, after fixing with the shell, and after instructing on the breathing method with the shell was 14.2 (interquartile range, 10.7-19.8), 11.5 (8.6-17.5), and 10.4 mm (7.3-15.8), respectively. Systematic and random errors of interfractional internal motion were all ≤2 mm in the left-right and anteroposterior directions and 3.7 and 3.0 mm, respectively, in the craniocaudal direction. Systematic and random errors of intrafractional internal motion were all ≤1.3 mm in the left-right and anteroposterior directions and 0.8 and 2.4 mm, respectively, in the craniocaudal direction.Conclusions
The device-free compressed shell fixation method was effective in suppressing the respiratory movement of the liver. Irradiation position matching using the fiducial marker can correct the interfractional internal motion on each day, which would contribute to the reduction of the margin to be given around the target. 相似文献![点击此处可从《Journal of the European Academy of Dermatology and Venereology》网站下载免费的PDF全文](/ch/ext_images/free.gif)