全文获取类型
收费全文 | 317篇 |
免费 | 43篇 |
出版年
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 33篇 |
2012年 | 10篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 14篇 |
2007年 | 15篇 |
2006年 | 7篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1971年 | 3篇 |
1969年 | 2篇 |
1966年 | 2篇 |
1943年 | 2篇 |
1915年 | 2篇 |
1897年 | 2篇 |
1883年 | 3篇 |
1882年 | 5篇 |
1881年 | 2篇 |
1879年 | 6篇 |
1878年 | 2篇 |
1877年 | 2篇 |
排序方式: 共有360条查询结果,搜索用时 15 毫秒
341.
342.
Plant Molecular Biology - 相似文献
343.
L D Faller 《Biochemistry》1989,28(16):6771-6778
ATP and the fluorescent substrate analogue TNP-ATP bind competitively to the gastric H,-K-ATPase. Substrate and product completely reverse the fluorescence enhancement caused by TNP-ATP binding to the enzyme. The fluorophore is displaced monophasically from apoenzyme. However, ATP displaces TNP-ATP from the Mg2+-quenched state in two steps of equal amplitude. The midpoints of the titrations differ by more than 2 orders of magnitude. The estimated substrate constants are in reasonable agreement with published Michaelis constants. TNP-ATP is not a substrate for the H,K-ATPase. The fluorophore prevents phosphorylation by ATP and competitively inhibits the K+-stimulated pNPPase and ATPase activities of the enzyme. Ki is approximately the same for both hydrolytic activities and consistent with the Kd of TNP-ATP measured directly. Km for pNPP is 1.48 +/- 0.15 mM. Two Michaelis constants are required to fit the ATPase data: Km1 = 0.10 +/- 0.01 mM and Km2 = 0.26 +/- 0.05 mM. 相似文献
344.
Christelle Hureau Christelle Mathé Peter Faller Tony A. Mattioli Pierre Dorlet 《Journal of biological inorganic chemistry》2008,13(7):1055-1064
The GGGTHSQW sequence in the amyloidogenic part of the prion protein is a potential binding site for Cu(II). We have previously
studied the binding of copper to the shorter GGGTH peptide and showed that it is highly pH dependent (Hureau et al. in J. Biol. Inorg. Chem. 11:735–744, 2006). Two predominant complexes could be characterized at pH 6.7 and 9.0 with equatorial binding modes of 3N1O and 4N for the
metal ion, respectively. In this work, we have further investigated the coordination of Cu(II) to the GGGTH peptide as well
as the longer GGGTHSQW peptide in order to identify the oxygen donor ligand at neutral pH and to study the proximity and redox
activity of the tryptophan residue of the latter. The results for both peptides show that, at pH 6.7, Cu(II) is coordinated
by a carbonyl peptide backbone. At higher pH values, the carbonyl ligand dissociates and the coordination changes to a 4N
binding mode, inducing a structural rearrangement that brings the GGGTHSQW peptide’s tryptophan residue into the vicinity
of the copper ion, thus affecting their respective redox properties. 相似文献
345.
D. G. Smith D. R. Buckle A. Faller I. L. Pinto 《Bioorganic & medicinal chemistry letters》1992,2(12):1595-1598
A series of C-4 pyrrole substituted benzopyrans and benzopyranols has been prepared, some members of which are potent relaxants of guinea pig trachealis in vitro. These compounds appear to act via potassium channel opening. It is envisaged that a pyrrole ring substituted with an electron-withdrawing group can function as a bioisostere of the pyrrolidinone of cromakalim. Two tetracyclic derivatives have been also prepared, one of which (18) appears to act as a potassium channel activator in a similar manner to cromakalim while the other (15), although a potent relaxant of guinea pig trachealis, has a profile which is inconsistent with this mechanism of action. 相似文献
346.
Adolf Faller 《Cell and tissue research》1942,32(2):173-193
Ohne Zusammenfassung 相似文献
347.
A Lillehaug C Monceyron Jonassen B Bergsj? M Hofshagen J Tharaldsen LL Nesse K Handeland 《Acta veterinaria Scandinavica》2005,46(4):193
A total of 119 fresh faecal samples were collected from graylag geese migrating northwards in April. Also, cloacal swabs were
taken from 100 carcasses of graylag geese shot during the hunting season in August. In addition, samples were taken from 200
feral pigeons and five mallards. The cultivation of bacteria detected Campylobacter jejuni jejuni in six of the pigeons, and in one of the mallards. Salmonella diarizona 14:k:z53 was detected in one graylag goose, while all pigeons and mallards were negative for salmonellae. No avian paramyxovirus
was found in any of the samples tested. One mallard, from an Oslo river, was influenza A virus positive, confirmed by RT-PCR
and by inoculation of embryonated eggs. The isolate termed A/Duck/Norway/1/03 was found to be of H3N8 type based on sequence
analyses of the hemagglutinin and neuraminidase segments, and serological tests. This is the first time an avian influenza
virus has been isolated in Norway. The study demonstrates that the wild bird species examined may constitute a reservoir for
important bird pathogens and zoonotic agents in Norway. 相似文献
348.
CLINTON W. EPPS JOHN D. WEHAUSEN PER J. PALSBØLL DALE R. MCCULLOUGH 《The Journal of wildlife management》2010,74(3):522-531
ABSTRACT Understanding colonization is vital for managing fragmented populations. We employed mitochondrial DNA haplotypes and 14 microsatellite (nuclear DNA) markers to infer the origins of newly established populations of desert bighorn sheep (Ovis canadensis nelsoni) and to assess loss of genetic diversity during natural colonizations. We used haplotype distribution, F-statistics, Bayesian population clustering, and assignment tests to infer source populations for 3 recent colonies and identified a previously undetected colonization from multiple source populations. Allelic richness declined in 3 of 4 colonies in comparison to the primary source populations, but not as much as has been reported for translocated populations. Heterozygosity declined in only one colony. We also demonstrated that both native and translocated desert bighorn sheep have naturally recolonized empty habitats and suggest that colonization may partially offset population extinction in the region as long as connectivity is maintained. Genetic techniques and mitochondrial DNA haplotypes we described will allow managers to determine the origins of future colonizations by bighorn sheep in California, USA, and prioritize protection of linkages between known sources and colonies. 相似文献
349.
In culture filtrates from the crayfish plague parasite, Aphanomyces astaci, protease and a low level of hyaluronidase activity were found. The hyaluronidase activity was highest at pH 6.5 or above and at about 23°C. The protease activity had a broad pH-optimum, between pH 7 and at least pH 10, and was partially denatured at 30°C. However, when incubated for 30 min with the substrate, casein, the activity increased logarithmically up to about 35–40°C and had an apparent optimum at 45–50°C. The proteases from the parasitic as well as from two less proteolytic, saprophytic Aphanomyces species were predominantly constitutive and were excreted mainly by the older mycelia. Proteases from the parasite and a saprophyte did not reach full activity until 10–30 min after substrate addition. No lipase activity was found in the case of the mycelium of the parasitic species. However, esterase was apparently present inside germinating zoospores. The native enzymes of A. astaci could degrade freeze-dried soft cuticle from crayfish. The relevance of the different enzymes of A. astaci for the penetration process within the cuticle of crayfish is discussed. 相似文献
350.