全文获取类型
收费全文 | 748篇 |
免费 | 121篇 |
国内免费 | 158篇 |
专业分类
1027篇 |
出版年
2023年 | 10篇 |
2022年 | 25篇 |
2021年 | 25篇 |
2020年 | 16篇 |
2019年 | 26篇 |
2018年 | 14篇 |
2017年 | 24篇 |
2016年 | 28篇 |
2015年 | 31篇 |
2014年 | 26篇 |
2013年 | 45篇 |
2012年 | 47篇 |
2011年 | 43篇 |
2010年 | 48篇 |
2009年 | 40篇 |
2008年 | 39篇 |
2007年 | 34篇 |
2006年 | 30篇 |
2005年 | 20篇 |
2004年 | 29篇 |
2003年 | 33篇 |
2002年 | 33篇 |
2001年 | 38篇 |
2000年 | 25篇 |
1999年 | 19篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1967年 | 7篇 |
1961年 | 4篇 |
1932年 | 4篇 |
排序方式: 共有1027条查询结果,搜索用时 15 毫秒
1.
Douglas G. Gilmour Walter M. Collins Tom L. Fredericksen Willard E. Urban Jr. Paul F. Ward Nancy L. DiFronzo 《Immunogenetics》1986,23(1):1-6
Chickens of Regional Poultry Research Laboratory (RPRL) inbred line 63 regress sarcomas induced by Bryan high-titer Rous sarcoma virus to a greater extent than chickens of line RPRL 100, although these lines are identical for the major histocompatibility B complex. They differ, however, at three independent autosomal loci: Ly-4 and Th-1 determine the surface alloantigens of partly overlapping subsets of T lymphocytes, and Bu-1 determines a surface alloantigen of B lymphocytes. The association of genotypes at these loci with quantitative variation in their ability to regress Rous sarcomas was tested in segregating F4 generation progeny derived from crosses of lines 100 and 63. The Ly-4 and Bu-1 genotypes showed association with Rous sarcoma regression, but the Th-1 genotype did not. Chickens of the Ly-4
a/Ly-4
a, Bu-1
b/Bu-1
b and Ly-4
b/Ly-4
b, Bu-1
a/Bu-1
a genotypes had a significantly higher regressor ability than the other two double homozygous genotypes. These results indicate that higher regression is associated with (1) interaction between the Ly-4 and Bu-1 loci, and (2) complementation between either the line 6 Ly-4
a allele and the line 100 Bu-1
b allele, or the line 100 Ly-4
b allele and the line 6 Bu-1
a allele. 相似文献
2.
3.
Microflora associated with the internal surfaces of rubber and stainless steel milk transfer pipeline 总被引:2,自引:0,他引:2
Sterile sections of rubber and stainless steel milk transfer pipeline were inserted sequentially into a milking installation and soiled with fresh raw milk over a period of 5 d. The resultant adherent microbial population was removed and the generic composition of mesophilic and psychotropic types was determined. In all cases Acinetobacter spp. were found to predominate (59.5-75.6%). The generic composition of the raw milk used to soil the milking unit (with inserted pipe section) was determined once during each 5-d soiling period. In general the milk was found to contain a mixed flora in which Gram-positive organisms predominated. 相似文献
4.
D. G. Gilmour J. R. Morton 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1971,41(2):57-66
Summary Association of the egg-white genotypes of dams with the mortality of their embryos was studied in 1966 in the pure and crossbred embryos of dams of two relatively noninbred Light Sussex substrains, 6D and 6F. These had been derived two generations earlier, in 1964, by equal division of strain 6, which we previously studied in 1962; while the sires of the crosses came from two Rhode Island Red/New Hampshire substrains, 5D and 5F, similarly derived. The effects were estimated parametrically for the three loci Tf, II and III singly and in two- and three-way interaction.In the first week of incubation, Tf had an additive effect in all matings, while II (and perhaps III) had a near-additive effect in the pure matings only. There was an additive X additive interaction effect of II X III in the last six days of incubation, which was consistent over all matings except 5F X 6F. The only effect to influence the total mortality over the whole of incubation was the three-way additive X additive X additive interaction, and there was substantial agreement in this over the matings. Some triple homozygotes were superior and others inferior to the genotypes with one or more loci heterozygous.This evidence of multiple interaction between loci affecting fitness is discussed in relation to hypotheses for the maintenance of genetic variability in populations. 相似文献
5.
6.
7.
Medicolegal issues in cardiopulmonary resuscitation (CPR) and emergency cardiac care were considered in the United States by the National Conference on Cardiopulmonary Resuscitation in 1985. This paper discusses these issues in the Canadian context. Although there is little legislation or case precedent in Canada to guide providers of CPR in decision-making, there appears to be little risk of liability or prosecution for competently rendered care. Providers should be cautious in withholding or withdrawing resuscitative measures from incompetent patients when brain death has not occurred and cardiovascular unresponsiveness has not been demonstrated. However, resuscitation may be withheld when a competent patient refuses it or if there is another medically and legally valid reason to do so. 相似文献
8.
F M Robertson S K Gilmour A J Beavis S M O'Connell A H Conney M T Huang J D Laskin O A Hietala T G O'Brien 《Cytometry》1990,11(7):832-836
Using flow cytometry in combination with membrane permeabilization techniques to enhance binding of antibodies with immunoreactive protein within the cytoplasm, we have developed a method to examine the ornithine decarboxylase (ODC) activity present within subpopulations of epidermal cells following acute and chronic exposure to the phorbol ester tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA). The method described has the sensitivity to detect basal levels of ODC as well as increases in ODC at early time points following treatment with TPA and has the additional advantage of allowing subpopulation identification and characterization. 相似文献
9.
B. R. Cullis F. M. Thomson J. A. Fisher A. R. Gilmour R. Thompson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(1):21-27
The retrospective analysis of a large database on wheat variety testing in New South Wales (NSW) is considered. This analysis involved three key steps. Initially error variance heterogeneity is modelled, indicating significant differences in error variance due to trial location, year of trialling, sowing date and trial mean yield. The implication of this modelling for the estimaion of variance components is discussed. 相似文献
10.
Incidence of Listeria spp. and Listeria monocytogenes in a poultry processing environment and in poultry products and their rapid confirmation by multiplex PCR. 总被引:1,自引:1,他引:0 下载免费PDF全文
The incidence of Listeria spp. and Listeria monocytogenes in a poultry processing plant and in raw and cooked poultry products was determined over a 6-month period. Within the raw and cooked poultry processing environments, 46% (36 of 79) and 29% (51 of 173) of the samples contained Listeria spp. while 26% (21 of 79) and 15% (27 of 173) contained L. monocytogenes, respectively. Various sites within the processing environment were found to be consistently positive for L. monocytogenes throughout the entire sampling period. Of the raw and cooked products tested, 91% (53 of 58) and 8% (8 of 96) were found to contain Listeria spp. while 59% (34 of 58) and 0% (0 of 96) contained L. monocytogenes, respectively. Although L. monocytogenes was not detected in the cooked products examined, the presence of other Listeria spp. highlights the potential which exists for postprocessing contamination. Multiplex PCR proved to be a convenient and time-saving technique for rapid confirmation of Listeria spp. and L. monocytogenes in a single reaction. 相似文献