首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   98篇
  免费   0篇
现状及发展   42篇
研究方法   7篇
综合类   49篇
  2016年   1篇
  2015年   1篇
  2012年   4篇
  2011年   6篇
  2008年   6篇
  2007年   5篇
  2006年   3篇
  2005年   6篇
  2004年   5篇
  2003年   2篇
  2002年   5篇
  2001年   2篇
  2000年   6篇
  1999年   4篇
  1996年   1篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1986年   1篇
  1983年   1篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1976年   2篇
  1974年   1篇
  1970年   2篇
  1969年   3篇
  1967年   1篇
  1966年   3篇
  1965年   3篇
  1963年   1篇
  1962年   2篇
  1961年   2篇
  1960年   2篇
  1959年   2篇
  1958年   3篇
  1956年   1篇
  1955年   2篇
  1948年   1篇
排序方式: 共有98条查询结果,搜索用时 31 毫秒
41.
Whole-genome sequence of Schistosoma haematobium   总被引:1,自引:0,他引:1  
Schistosomiasis is a neglected tropical disease caused by blood flukes (genus Schistosoma; schistosomes) and affecting 200 million people worldwide. No vaccines are available, and treatment relies on one drug, praziquantel. Schistosoma haematobium has come into the spotlight as a major cause of urogenital disease, as an agent linked to bladder cancer and as a predisposing factor for HIV/AIDS. The parasite is transmitted to humans from freshwater snails. Worms dwell in blood vessels and release eggs that become embedded in the bladder wall to elicit chronic immune-mediated disease and induce squamous cell carcinoma. Here we sequenced the 385-Mb genome of S. haematobium using Illumina-based technology at 74-fold coverage and compared it to sequences from related parasites. We included genome annotation based on function, gene ontology, networking and pathway mapping. This genome now provides an unprecedented resource for many fundamental research areas and shows great promise for the design of new disease interventions.  相似文献   
42.
43.
The primary structure of a voltage-dependent calcium channel from rabbit brain has been deduced by cloning and sequencing the complementary DNA. Calcium channel activity expressed from the cDNA is dramatically increased by coexpression of the alpha 2 and beta subunits, known to be associated with the dihydropyridine receptor. This channel is a high voltage-activated calcium channel that is insensitive both to nifedipine and to omega-conotoxin. We suggest that it is expressed predominantly in cerebellar Purkinje cells and granule cells.  相似文献   
44.
Summary The time function of corticosteroid level in plasma of rats under two different222Rn concentrations was investigated. Both curves show a maximum after 8 h. Whereas the higher activity of222Rn produces a second maximum after 5 days, the lower activity reaches its second maximum not before 9 days. From both time functions, a two-step mechanism in the intracellular control can be concluded.  相似文献   
45.
Summary In experiments with a sufficiently great number of observers, using our spectral colour integrator, it has been shown thatone colour containing a maximum of chromatic power (chroma) can be chosen out of a series of optimal colours continuously changeable from white over the fullcolour to black. The determination of such maximal colours, differing in hue, shows their position between fullcolour and spectral colour in the mixing metric colour solid. Their relation to maximal properties of scalemetrically defined chromatic power functions is discussed.  相似文献   
46.
Transduction in taste receptor cells requires cAMP-dependent protein kinase   总被引:11,自引:0,他引:11  
P Avenet  F Hofmann  B Lindemann 《Nature》1988,331(6154):351-354
In taste chemoreception, cyclic adenosine monophosphate (cAMP) appears to be one of the intracellular messengers coupling reception of stimulus to the generation of the response. The recent finding that sweet agents cause a GTP-dependent generation of cAMP poses the question of how this cytosolic messenger acts at the membrane of taste receptor cells. We have shown that cAMP causes a substantial depolarization in these cells. Here we show with whole-cell recordings and inside-out membrane patches that the depolarization caused by cAMP is accounted for by the action of cAMP-dependent protein kinase, which inactivates potassium channels predominantly of 44 pS conductance. Thus, intracellular signalling of the gustatory cells differs from that of olfactory and photoreceptor cells, where cyclic nucleotides control unspecific channels by binding to them rather than by inducing their phosphorylation.  相似文献   
47.
Summary Ergot alkaloids of the peptide type and their dihydro-derivatives can be converted reversibly in acid solution into isomeric compounds. They are characterised by the prefix aci, e.g. aci-ergotamine, aci-dihydro-ergotamine. The isomerisation takes place in the peptide part of the molecule.

49. Mitteilung über Mutterkornalkaloide. 48. Mitt. s. Helv. chim. Acta42, 2696 (1959).  相似文献   
48.
Proteasomal receptors that recognize ubiquitin chains attached to substrates are key mediators of selective protein degradation in eukaryotes. Here we report the identification of a new ubiquitin receptor, Rpn13/ARM1, a known component of the proteasome. Rpn13 binds ubiquitin through a conserved amino-terminal region termed the pleckstrin-like receptor for ubiquitin (Pru) domain, which binds K48-linked diubiquitin with an affinity of approximately 90 nM. Like proteasomal ubiquitin receptor Rpn10/S5a, Rpn13 also binds ubiquitin-like (UBL) domains of UBL-ubiquitin-associated (UBA) proteins. In yeast, a synthetic phenotype results when specific mutations of the ubiquitin binding sites of Rpn10 and Rpn13 are combined, indicating functional linkage between these ubiquitin receptors. Because Rpn13 is also the proteasomal receptor for Uch37, a deubiquitinating enzyme, our findings suggest a coupling of chain recognition and disassembly at the proteasome.  相似文献   
49.
50.
Abouchami W  Hofmann AW  Galer SJ  Frey FA  Eisele J  Feigenson M 《Nature》2005,434(7035):851-856
The two parallel chains of Hawaiian volcanoes ('Loa' and 'Kea') are known to have statistically different but overlapping radiogenic isotope characteristics. This has been explained by a model of a concentrically zoned mantle plume, where the Kea chain preferentially samples a more peripheral portion of the plume. Using high-precision lead isotope data for both centrally and peripherally located volcanoes, we show here that the two trends have very little compositional overlap and instead reveal bilateral, non-concentric plume zones, probably derived from the plume source in the mantle. On a smaller scale, along the Kea chain, there are isotopic differences between the youngest lavas from the Mauna Kea and Kilauea volcanoes, but the 550-thousand-year-old Mauna Kea lavas are isotopically identical to Kilauea lavas, consistent with Mauna Kea's position relative to the plume, which was then similar to that of present-day Kilauea. We therefore conclude that narrow (less than 50 kilometres wide) compositional streaks, as well as the larger-scale bilateral zonation, are vertically continuous over tens to hundreds of kilometres within the plume.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号