全文获取类型
收费全文 | 105篇 |
免费 | 50篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 15篇 |
基础医学 | 51篇 |
临床医学 | 11篇 |
内科学 | 26篇 |
皮肤病学 | 13篇 |
神经病学 | 8篇 |
特种医学 | 3篇 |
外科学 | 11篇 |
预防医学 | 12篇 |
药学 | 2篇 |
肿瘤学 | 2篇 |
出版年
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 1篇 |
1963年 | 1篇 |
1960年 | 3篇 |
排序方式: 共有155条查询结果,搜索用时 109 毫秒
1.
2.
The effects of aerobic conditioning and/or caloric restriction in overweight men and women 总被引:1,自引:0,他引:1
The purpose of this study was to compare the effects of exercise and/or caloric restriction for 12 wk on body composition, maximal aerobic power (VO2max), and serum lipids and lipoproteins in overweight individuals. Forty-eight males and 48 females (means age = 36.6 yr), 120-140% of ideal body weight, were randomly assigned to groups (N = 12 each) of diet-exercise (DE), diet (D), exercise (E), and sedentary control (C). The dietary regimen consisted of 1,200 kcal X d-1, while exercise consisted of 5 d X wk-1 of 30 min of walk/running. For the males, body weight (BW) and fat weight loss in the DE group (-11.8 and 23%, respectively) were significantly greater than in the D group (-9.1 and -18%), with both groups significantly greater than for E and C. In the females, BW and fat weight loss for DE (-10.4 and -24%) were significantly greater than for D (-7.8 and -20%), with both groups significantly greater than E and C. Both DE and D males and females had a decrease in fat-free weight of -4.5 and -2.4%, respectively. In both sexes, the increase in VO2max-BW (ml X kg -1 X min-1) in DE (25%) was significantly greater than for E (15%), D (11%), and C (0%), with differences between E and D nonsignificant. However, increases in absolute VO2max (1 X min-1) and VO2max-fat-free weight (ml X kg-1 X min-1) were similar (P greater than 0.05) for DE and E (14%) but significantly greater compared to D and C (2%).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Population genetics of pathogenic bacteria 总被引:26,自引:0,他引:26
4.
Molecular characterization of a serotype O121:H19 clone,a distinct Shiga toxin-producing clone of pathogenic Escherichia coli 下载免费PDF全文
Tarr CL Large TM Moeller CL Lacher DW Tarr PI Acheson DW Whittam TS 《Infection and immunity》2002,70(12):6853-6859
Most illnesses caused by Shiga toxin-producing Escherichia coli (STEC) have been attributed to E. coli serotype O157:H7, but non-O157 STEC infections are now increasingly recognized as public health problems worldwide. The O121:H19 serotype is being isolated more frequently from clinical specimens and has been implicated in one waterborne outbreak. We used multilocus virulence gene profiling, a PCR-based assay, to characterize the virulence gene content of 24 isolates of serotype O121:H19 and nonmotile variants. We also performed multilocus enzyme electrophoresis and multilocus sequencing to establish the clonal relatedness of O121 isolates and to elucidate the relationship of O121 to common STEC clones. The 24 isolates were found to represent a single bacterial clone, as there was no allelic variation across 18 enzyme loci among the isolates. The complete nucleotide sequence of the intimin gene differed by four substitutions from that of the epsilon (Int- epsilon ) allele of O103:H2 strain PMK5. The typical O121 virulence gene profile was similar to the profiles of enterohemorrhagic E. coli (EHEC) clones of E. coli: it included a Shiga toxin 2 gene (stx(2)), two genes on the EHEC plasmid (toxB and ehxA), and the gene encoding intimin (eae). Despite the similarities, putative virulence genes distributed on O islands-large chromosomal DNA segments present in the O157:H7 genome-were useful for discriminating among STEC serotypes and the O121:H19 clone had a composite profile that was distinct from the profiles of the other major EHEC clones of pathogenic E. coli. On the basis of sequencing analysis with 13 housekeeping genes, the O121:H19 clone did not fall into any of the four classical EHEC and enteropathogenic E. coli groups but instead was closely related to two eae-negative STEC strains. 相似文献
5.
6.
Chamberlain Jayne L. Huda Saif Whittam Daniel H. Matiello Marcelo Morgan B. Paul Jacob Anu 《Journal of neurology》2021,268(5):1665-1665
Journal of Neurology - The original version of this article unfortunately contained a mistake. Fifth sentence of the fourth paragraph in the section “Non-nAChR autoantibody targets in... 相似文献
7.
Allelic variation in human mitochondrial genes based on patterns of restriction site polymorphism. 总被引:9,自引:3,他引:9 下载免费PDF全文
T S Whittam A G Clark M Stoneking R L Cann A C Wilson 《Proceedings of the National Academy of Sciences of the United States of America》1986,83(24):9611-9615
Restriction maps of 145 human mtDNAs representing samples from five geographic regions were used to construct multilocus genotypes for 28 genetic loci of the mitochondrial genome. Alleles were defined as distinct combinations of the presence or absence of polymorphic restriction sites within each locus. The 28 loci included 13 genes encoding proteins, 10 genes specifying tRNAs, 2 genes specifying rRNAs, and 3 noncoding regions consisting of the D loop, the light strand origin of replication, and the 5' noncoding sequence. In 35 comparisons of allele frequency distributions to expected distributions predicted by neutral mutation theory (assuming an infinite alleles model), the results revealed that most genetic diversity values (71%) fell within the range predicted by the neutral model; however, excesses in the frequencies of common alleles and in the number of singleton alleles within populations were observed at specific loci. Departures from the neutral mutation model are most readily explained by the effects of the recent expansion of the human population and the action of purifying selection. Coefficients of population differentiation suggest that gene flow of mtDNA types between certain geographic regions may be limited. 相似文献
8.
9.
10.