全文获取类型
收费全文 | 72篇 |
免费 | 13篇 |
出版年
2018年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 3篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1972年 | 6篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 5篇 |
1968年 | 7篇 |
1967年 | 2篇 |
1966年 | 3篇 |
1962年 | 1篇 |
排序方式: 共有85条查询结果,搜索用时 265 毫秒
1.
A convenient program for the rapid calculation of sedimentation coefficients in linear salt or sucrose gradients 总被引:4,自引:0,他引:4
C W Dingman 《Analytical biochemistry》1972,49(1):124-133
A program is presented for calculating s20,w values from data obtained by zone sedimentation in linear sucrose or salt gradients in a variety of rotors at temperatures ranging from 0° to 20°C. The program can be either run with the use of high-speed computers or performed with the aid of a small calculator in a reasonably short time. 相似文献
2.
3.
4.
The Habsburg jaw 总被引:3,自引:0,他引:3
5.
6.
7.
8.
Current status of antisense DNA methods in behavioral studies 总被引:4,自引:0,他引:4
The antisense DNA method has been used successfully to block the expression
of specific genes in vivo in neuronal systems. An increasing number of
studies in the last few years have shown that antisense DNA administered
directly into the brain can modify various kinds of behaviors. These
findings strongly suggest that the antisense DNA method can be used as a
powerful tool to study causal relationships between molecular processes in
the brain and behavior. In this article we review the current status of the
antisense method in behavioral studies and discuss its potentials and
problems by focusing on the following four aspects; (i) optimal application
paradigms of antisense DNA methods in behavioral studies; (ii) efficiencies
of different administration methods of antisense DNA used in behavioral
studies; (iii) determination of specificity of behavioral effects of
antisense DNA; and (iv) discrepancies between antisense DNA effects on
behaviors and those on protein levels of the targeted gene.
相似文献
9.
Paul DW Kirk Aviva Witkover Alan Courtney Alexandra M Lewin Robin Wait Michael PH Stumpf Sylvia Richardson Graham P Taylor Charles RM Bangham 《Retrovirology》2011,8(1):1-9
Background
A new subgroup of HIV-1, designated Group P, was recently detected in two unrelated patients of Cameroonian origin. HIV-1 Group P phylogenetically clusters with SIVgor suggesting that it is the result of a cross-species transmission from gorillas. Until today, HIV-1 Group P has only been detected in two patients, and its degree of adaptation to the human host is largely unknown. Previous data have shown that pandemic HIV-1 Group M, but not non-pandemic Group O or rare Group N viruses, efficiently antagonize the human orthologue of the restriction factor tetherin (BST-2, HM1.24, CD317) suggesting that primate lentiviruses may have to gain anti-tetherin activity for efficient spread in the human population. Thus far, three SIV/HIV gene products (vpu, nef and env) are known to have the potential to counteract primate tetherin proteins, often in a species-specific manner. Here, we examined how long Group P may have been circulating in humans and determined its capability to antagonize human tetherin as an indicator of adaptation to humans.Results
Our data suggest that HIV-1 Group P entered the human population between 1845 and 1989. Vpu, Env and Nef proteins from both Group P viruses failed to counteract human or gorilla tetherin to promote efficient release of HIV-1 virions, although both Group P Nef proteins moderately downmodulated gorilla tetherin from the cell surface. Notably, Vpu, Env and Nef alleles from the two HIV-1 P strains were all able to reduce CD4 cell surface expression.Conclusions
Our analyses of the two reported HIV-1 Group P viruses suggest that zoonosis occurred in the last 170 years and further support that pandemic HIV-1 Group M strains are better adapted to humans than non-pandemic or rare Group O, N and P viruses. The inability to antagonize human tetherin may potentially explain the limited spread of HIV-1 Group P in the human population. 相似文献10.
To determine the response of human cortical bone to projectile impact, 364 projectile impact tests were conducted on the shafts of embalmed human femurs. Chrome steel spherical projectiles in two diameters, 0·250 and 0·406 in., were employed to differentiate the effects of projectiles of varied sizes and masses in impacts at the same velocity. It was found that the larger projectiles expended significantly more energy in fracturing a femur than the smaller projectiles did at an identical impact velocity. Also, when impacts in which larger and smaller spheres possessed identical kinetic energies were compared, it was found that the larger spheres still expended more energy in fracturing the femur. Finally, it was clearly demonstrated by these experiments that impacts to cortical bone of the femoral shaft by either size projectile caused greater energy expenditure than impacts to the distal end of the femur, which is composed almost entirely of cancellous bone. 相似文献