全文获取类型
收费全文 | 68篇 |
免费 | 3篇 |
国内免费 | 2篇 |
出版年
2021年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1980年 | 1篇 |
1974年 | 2篇 |
1971年 | 4篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1962年 | 2篇 |
1960年 | 2篇 |
1958年 | 2篇 |
1957年 | 3篇 |
1956年 | 1篇 |
1953年 | 1篇 |
1952年 | 3篇 |
排序方式: 共有73条查询结果,搜索用时 15 毫秒
31.
RICHARD BISCHOF RIKAKO FUJITA ANDREAS ZEDROSSER ARNE SÖDERBERG JON E. SWENSON 《The Journal of wildlife management》2008,72(1):79-88
Abstract We analyzed harvest data to describe hunting patterns and harvest demography of brown bears (Ursus arctos) killed in 3 geographic regions in Sweden during 1981–2004. In addition, we investigated the effects of a ban on baiting, instituted in 2001, and 2 major changes in the quota system: a switch to sex-specific quotas in 1992 and a return to total quotas in 1999. Brown bears (n=887) were harvested specifically by bear hunters and incidentally by moose (Alces alces) hunters. Both hunter categories harvested bears 1) using dogs (37%), 2) by still hunting (30%), 3) with the use of bait (18%), and 4) by stalking (16%). The proportion of bears killed with different harvest methods varied among regions and between bear- and moose-oriented hunters. We found differences between male (52%) and female bears (48%) with respect to the variables that explained age. Moose-oriented hunters using still hunting harvested the youngest male bears. Bears harvested during the first management period (1981–1991) were older and had greater odds of being male than during the subsequent period. It appears that hunters harvesting bears in Sweden are less selective than their North American counterparts, possibly due to differences in the hunting system. When comparing the 4 years immediately prior to the ban on baiting with the 4 years following the ban, we found no differences in average age of harvested bears, sex ratio, or proportion of bears killed with stalking, still hunting, and hunting with dogs, suggesting that the ban on baiting in Sweden had no immediate effect on patterns of brown bear harvest demography and remaining hunting methods. As the demographic and evolutionary side effects of selective harvesting receive growing attention, wildlife managers should be aware that differences in harvest systems between jurisdictions may cause qualitative and quantitative differences in harvest biases. (JOURNAL OF WILDLIFE MANAGEMENT 72(1):79–88; 2008) 相似文献
32.
33.
Adebola AJ Raji James V Anderson Olufisayo A Kolade Chike D Ugwu Alfred GO Dixon Ivan L Ingelbrecht 《BMC plant biology》2009,9(1):118-11
Background
Cassava (Manihot esculenta Crantz), a starchy root crop grown in tropical and subtropical climates, is the sixth most important crop in the world after wheat, rice, maize, potato and barley. The repertoire of simple sequence repeat (SSR) markers for cassava is limited and warrants a need for a larger number of polymorphic SSRs for germplasm characterization and breeding applications. 相似文献34.
Helper Function of Follicle Cells in Sperm-Egg Interactions of the Ascidian, Ciona intestinalis 总被引:2,自引:2,他引:0
KAZUO KAWAMURA HIROKO FUJITA MITSUAKI NAKAUCHI 《Development, growth & differentiation》1988,30(6):693-703
Studies were made on the involvement in sperm-egg interactions of follicle cells of Ciona intestinalis , which are tall, vacuolated cells attached to the outer surface of the egg vitelline coat. The basal surface of the follicle cells is polygonal. The borders between cells could easily be observed by the binding of fluorescent SBA (soy bean agglutinin), a lectin recognizing N-acetylgalactosamine (GaINAc) residues. At fertilization many spermatozoa aggregate along these polygonal borders of cells on the vitelline coat, through which they entered the perivitelline space. The removal of follicle cells was sometimes associated with loss of SBA-binding sites, and in such cases the sperm did not show a hexagonal pattern of aggregation, but became dispersed all over the vitelline coat. Removal of the follicle sometimes delayed fertilization. Examination of sections of gametes stained with DAPI, a fluorescent dye staining DNA, showed that removal of the follicle reduced the number of spermatozoa bound to the vitelline coat and, more especially, the number of spermatozoa penetrating through the vitelline coat. The blockage of GalNAc residues on the vitelline coat with SBA did not appreciably affect the time course of fertilization or the number of sperm associated with eggs. These findings are discussed in relation to the role of follicle cells in facilitating sperm aggregation on the vitelline coat and their penetration through it. 相似文献
35.
Eight dinucleotide microsatellite markers were developed on Hymeniacidon sinapium (Porifera: Demospongiae), common littoral sponge around Japan, to investigate population genetic structure. Two to 10 alleles were identified in an analysis of 24 individuals of H. sinapium, with observed heterozygosity ranging from 0.04 to 0.83. All loci did not deviate from the Hardy–Weinberg expectations; however, significant linkage disequilibrium between Sinp126 and Sinp142 was found. 相似文献
36.
S Lee MJ Emond MJ Bamshad KC Barnes MJ Rieder DA Nickerson;NHLBI GO Exome Sequencing Project—ESP Lung Project Team DC Christiani MM Wurfel X Lin 《American journal of human genetics》2012,91(2):224-237
We propose in this paper a unified approach for testing the association between rare variants and phenotypes in sequencing association studies. This approach maximizes power by adaptively using the data to optimally combine the burden test and the nonburden sequence kernel association test (SKAT). Burden tests are more powerful when most variants in a region are causal and the effects are in the same direction, whereas SKAT is more powerful when a large fraction of the variants in a region are noncausal or the effects of causal variants are in different directions. The proposed unified test maintains the power in both scenarios. We show that the unified test corresponds to the optimal test in an extended family of SKAT tests, which we refer to as SKAT-O. The second goal of this paper is to develop a small-sample adjustment procedure for the proposed methods for the correction of conservative type I error rates of SKAT family tests when the trait of interest is dichotomous and the sample size is small. Both small-sample-adjusted SKAT and the optimal unified test (SKAT-O) are computationally efficient and can easily be applied to genome-wide sequencing association studies. We evaluate the finite sample performance of the proposed methods using extensive simulation studies and illustrate their application using the acute-lung-injury exome-sequencing data of the National Heart, Lung, and Blood Institute Exome Sequencing Project. 相似文献
37.
Antibodies specific to the granulosis virus (GV) of the codling moth (Cydia pomonella) were detected by indirect ELISA in sera of woodmice (Apodemus sylvaticus) trapped in an apple orchard sprayed by tractor-drawn mist blower with 2 × 1013 virus granules C. pomonella GV/ha. Such antibodies were absent from sera of mice trapped before virus had been applied. Virus antigens were detected by double antibody sandwich ELISA on the ground in and around the orchard and also in the faeces of woodmice inhabiting the orchard, but did not persist from one year to another. Some, but not all, of the samples containing virus antigens were found to be infective. 相似文献
38.
39.
40.