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排序方式: 共有326条查询结果,搜索用时 15 毫秒
91.
Reconstitution of KCNE1 into lipid bilayers: comparing the structural, dynamic, and activity differences in micelle and vesicle environments 总被引:1,自引:0,他引:1
Coey AT Sahu ID Gunasekera TS Troxel KR Hawn JM Swartz MS Wickenheiser MR Reid RJ Welch RC Vanoye CG Kang C Sanders CR Lorigan GA 《Biochemistry》2011,50(50):10851-10859
KCNE1 (minK), found in the human heart and cochlea, is a transmembrane protein that modulates the voltage-gated potassium KCNQ1 channel. While KCNE1 has previously been the subject of extensive structural studies in lyso-phospholipid detergent micelles, key observations have yet to be confirmed and refined in lipid bilayers. In this study, a reliable method for reconstituting KCNE1 into lipid bilayer vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho(1'-rac-glycerol) (sodium salt) (POPG) was developed. Microinjection of the proteoliposomes into Xenopus oocytes expressing the human KCNQ1 (K(V)7.1) voltage-gated potassium channel led to nativelike modulation of the channel. Circular dichroism spectroscopy demonstrated that the percent helicity of KCNE1 is significantly higher for the protein reconstituted in lipid vesicles than for the previously described structure in 1.0% 1-myristoyl-2-hydroxy-sn-glycero-3-phospho(1'-rac-glycerol) (sodium salt) (LMPG) micelles. SDSL electron paramagnetic resonance spectroscopic techniques were used to probe the local structure and environment of Ser28, Phe54, Phe57, Leu59, and Ser64 of KCNE1 in both POPC/POPG vesicles and LMPG micelles. Spin-labeled KCNE1 cysteine mutants at Phe54, Phe57, Leu59, and Ser64 were found to be located inside POPC/POPG vesicles, whereas Ser28 was found to be located outside the membrane. Ser64 was shown to be water inaccessible in vesicles but found to be water accessible in LMPG micelle solutions. These results suggest that key components of the micelle-derived structure of KCNE1 extend to the structure of this protein in lipid bilayers but also demonstrate the need to refine this structure using data derived from the bilayer-reconstituted protein to more accurately define its native structure. This work establishes the basis for such future studies. 相似文献
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Jaclyn R. Aliperti Dirk H. Van Vuren Aviva J. Rossi Kenneth B. Armitage 《Ethology : formerly Zeitschrift fur Tierpsychologie》2020,126(3):i-i
Maternal investment in mammals may take many forms, including spatial relocation of offspring. Litter relocation behavior, in which a female moves her litter to a new location, has been reported for several species of carnivores and rodents but has received little study. We describe litter relocations during long-term studies of two species of ground-dwelling squirrels, yellow-bellied marmots (YBM, Marmota flaviventer) and golden-mantled ground squirrels (GMGS, Callospermophilus lateralis), to determine the distance and frequency of litter relocations and to explore possible explanations for litter relocation behavior. We observed 19 litters relocated by YBM mothers and 32 by GMGS mothers. Although YBM are much larger than GMGS, relocation distances for YBM (median = 46 m and range = 15–324 m) were not greater than those for GMGS (median = 79 m and range = 16–252 m), possibly because YBM home ranges in our study area were exceptionally small. Frequency of litter relocation was greater for GMGS (21% of litters produced) than for YBM (10%), perhaps because GMGS experience fewer social constraints or greater predation risk. We identified several possible costs (energy expenditure and vulnerability to predators while transporting young) and benefits (reduced exposure to predation risk, increased habitat quality, and social benefits) of litter relocation. Future studies should continue to explore litter relocations to better understand the ecological causes and consequences of this behavior. 相似文献
95.
Role of the Jak/STAT pathway in the regulation of interleukin-8 transcription by oxidized phospholipids in vitro and in atherosclerosis in vivo 总被引:1,自引:0,他引:1
Gharavi NM Alva JA Mouillesseaux KP Lai C Yeh M Yeung W Johnson J Szeto WL Hong L Fishbein M Wei L Pfeffer LM Berliner JA 《The Journal of biological chemistry》2007,282(43):31460-31468
96.
Damon DH Teriele JA Marko SB 《American journal of physiology. Heart and circulatory physiology》2007,293(1):H266-H273
Vascular sympathetic innervation is an important determinant of blood pressure and blood flow. The mechanisms that determine vascular sympathetic innervation are not well understood. The present study tests the hypothesis that vascular-derived artemin promotes the development of sympathetic innervation to blood vessels by promoting sympathetic axon growth. RT-PCR and Western analyses indicate that artemin is expressed by cultured vascular smooth muscle and arteries, and artemin coreceptors, glial cell-derived neurotrophic factor family receptor alpha3 and ret, are expressed by postganglionic sympathetic neurons. The effects of artemin on axon growth were assessed on explants of neonatal rat sympathetic ganglia. In the presence, but not in the absence, of nerve growth factor, exogenous artemin stimulated neurite growth. Femoral arteries (FA) from adult rats contain artemin, and these arteries stimulated sympathetic neurite growth. Growth in the presence of FA was 92.2 +/- 11.9 mm, and that in the absence of FA was 26.3 +/- 5.4 mm (P < 0.05). FA stimulation of axon growth was reduced by an antibody that neutralized the activity of artemin (P < 0.05). These data indicate that artemin is expressed in arteries, and its receptors are expressed and functional in the postganglionic sympathetic neurons that innervate them. This suggests that artemin may be a determinant of vascular sympathetic innervation. 相似文献
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Smith JA Tierney SM Park YC Fuller S Schwarz MP 《Molecular phylogenetics and evolution》2007,43(3):1131-1137
Phylogenetic studies on insect social parasites have found very close host-parasite relationships, and these have often been interpreted as providing evidence for sympatric speciation. However, such phylogenetic inferences are problematic because events occurring after the origin of parasitism, such as extinction, host switching and subsequent speciation, or an incomplete sampling of taxa, could all confound the interpretation of phylogenetic relationships. Using a tribe of bees where social parasitism has repeatedly evolved over a wide time-scale, we show the problems associated with phylogenetic inference of sympatric speciation. Host-parasite relationships of more ancient species appear to support sympatric speciation, whereas in a case where parasitism has evolved very recently, sympatric speciation can be ruled out. However, in this latter case, a single extinction event would have lead to relationships that support sympatric speciation, indicating the importance of considering divergence ages when analysing the modes of social parasite evolution. 相似文献
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Jessica F. Bruhn Katherine C. Barnett Jaclyn Bibby Jens M. H. Thomas Ronan M. Keegan Daniel J. Rigden Zachary A. Bornholdt Erica Ollmann Saphire 《Journal of virology》2014,88(1):758-762
The Nipah virus phosphoprotein (P) is multimeric and tethers the viral polymerase to the nucleocapsid. We present the crystal structure of the multimerization domain of Nipah virus P: a long, parallel, tetrameric, coiled coil with a small, α-helical cap structure. Across the paramyxoviruses, these domains share little sequence identity yet are similar in length and structural organization, suggesting a common requirement for scaffolding or spatial organization of the functions of P in the virus life cycle. 相似文献