全文获取类型
收费全文 | 120篇 |
免费 | 9篇 |
国内免费 | 13篇 |
出版年
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1961年 | 1篇 |
1958年 | 3篇 |
1957年 | 6篇 |
1956年 | 3篇 |
1955年 | 1篇 |
1954年 | 1篇 |
1953年 | 7篇 |
1952年 | 4篇 |
排序方式: 共有142条查询结果,搜索用时 31 毫秒
71.
72.
Yeast cells, when grown in the presence of arsenate, are capable of accumulating phosphoinositides (PI) at the expense of inhibiting their degradation more than their synthesis. PI levels return to normal when the cells are cultured or exposed to media without arsenate. These reversible changes are employed as a tool to test the effect of inositide accumulation and dynamics on several membrane properties. In the PI-rich cells, phosphate and arsenate transport from low external concentrations (high affinity systems), as well as the transport of glycine, which enter the cells accompanied by protons, were increased. The proton ejection energized by glucose is also enhanced in the PI-rich cells that show a more efficient potassium inflow at pH 4.0-4.5. The membrane surface potential of the PI-rich cells was found to be 2-times higher than that of the normal cells, in agreement with the 2-fold increment in the PI. All the above mentioned alterations in membrane properties are reverted when the PI content of the PI-rich cells is reduced to the level of normal cells. The results show the participation of the phosphoinositides in the formation, maintenance and regulation of the membrane surface potential and their possible influence upon transport mechanisms. 相似文献
73.
Campos-Sánchez R Barrantes R Silva S Escamilla M Ontiveros A Nicolini H Mendoza R Munoz R Raventos H 《Human biology; an international record of research》2006,78(5):551-563
Two hundred seventeen male subjects from Costa Rica, Mexico, and the Hispanic population of the southwestern United States were studied. Twelve Y-chromosome STRs and the HVSI sequence of the mtDNA were analyzed to describe their genetic structure and to compare maternal and paternal lineages. All subjects are part of two NIMH-funded studies to localize schizophrenia susceptibility genes in Hispanic populations of Mexican and Central American ancestry. We showed that these three populations are similar in their internal genetic characteristics, as revealed by analyses of mtDNA and Y-chromosome STR diversity. These populations are related through their maternal lineage in a stronger way than through their paternal lineage, because a higher number of shared haplotypes and polymorphisms are seen in the mtDNA (compared to Y-chromosome STRs). These results provide evidence of previous contact between the three populations and shared histories. An analysis of molecular variance revealed no genetic differentiation for the mtDNA for the three populations, but differentiation was detected in the Y-chromosome STRs. Genetic distance analysis showed that the three populations are closely related, probably as a result of migration between close neighbors, as indicated by shared haplotypes and their demographic histories. This relationship could be an important common feature for genetic studies in Latin American and Hispanic populations. 相似文献
74.
75.
NO signalling in cytokinin-induced programmed cell death 总被引:6,自引:0,他引:6
FRANCESCO CARIMI MICHELA ZOTTINI ALEX COSTA IRENE CATTELAN ROBERTO DE MICHELE MARIO TERZI & FIORELLA LO SCHIAVO 《Plant, cell & environment》2005,28(9):1171-1178
Cell death can be induced by cytokinin 6-benzylaminopurine (BA) at high dosage in suspension-cultured Arabidopsis cells. Herein, we provide evidence that BA induces nitric oxide (NO) synthesis in a dose-dependent manner. A reduction in cell death can be observed when the cytokinin is supplemented with the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) or the nitric oxide synthase (NOS) inhibitors: 2-aminoethyl-isothiourea (AET) and NG.-monomethyl- l -arginine ( l -NMMA), which suggests that NO is produced via a NOS and is a signalling component of this form of programmed cell death. In BA-treated cells, mitochondrial functionality is altered via inhibition of respiration. This inhibition can be prevented by addition of either cPTIO or AET implying that NO acts at the mitochondrial level. 相似文献
76.
77.
Jesús Caro Diego Ontiveros Juan M. Pleguezuelos 《European Journal of Wildlife Research》2011,57(4):729-736
Although many studies have investigated the feeding habits of Palaearctic raptors, few have analysed non-breeding populations
during dispersal. Bonelli’s eagle (Aquila fasciata), a threatened species in Western Europe, has a relatively long and critical dispersal period. We studied feeding habits,
prey selection, and the influence of prey density on floater abundance in this species during its dispersal period in southern
Spain. Differences were found between the diet of floaters and that of the closest breeding populations. Diet diversity was
rather low for floaters, with European wild rabbits (Oryctolagus cuniculus) being the main prey and the only prey positively selected. Moreover, the number of floater Bonelli’s eagles observed in
the dispersal areas was positively associated with rabbit abundance. Other prey included red-legged partridges (Alectoris rufa) and pigeons (Columba sp.). We propose measures to match suitable prey availability for floater eagles in settlement areas and the use of such
areas as human hunting fields. 相似文献
78.
Radiation injury in the skin causes radiodermatitis, a condition in which the skin becomes inflamed and the epidermis can break down. This condition causes significant morbidity and if severe it can be an independent factor that contributes to radiation mortality. Radiodermatitis is seen in some settings of radiotherapy for cancer and is also of concern as a complication post-radiation exposure from accidents or weapons, such as a "dirty bomb". The pathogenesis of this condition is incompletely understood. Here we have developed a murine model of radiodermatitis wherein the skin is selectively injured by irradiation with high-energy electrons. Using this model we showed that the interleukin-1 (IL-1) pathway plays a significant role in the development of radiodermatitis. Mice that lack either IL-1 or the IL-1 receptor developed less inflammation and less severe pathological changes in their skin, especially at later time-points. These findings suggest that IL-1 pathway may be a potential therapeutic target for reducing the severity of radiodermatitis. 相似文献
79.
80.
The red coral grouper, Plectropomus maculatus, is a high value marine food fish species. We isolated the first set of 10 polymorphic microsatellites and examined their polymorphism in two related species: the Malabar grouper Epinephelus malabaricus and the brown‐marbled grouper Epinephelus fuscoguttatus. The average allele number of these 10 microsatellite DNA loci is 9.1/locus with a range of four to 17, whereas the expected heterozygosity ranged from 0.18 to 0.94, averaging 0.76. Five of the 10 markers amplified polymorphic and specific products in E. malabaricus, whereas only four were amplified in E. fuscoguttatus. These microsatellites could be applicable to captive breeding and to the studies on genetic diversity and population structure of grouper wild stocks. 相似文献