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排序方式: 共有183条查询结果,搜索用时 31 毫秒
1.
Cholera toxin blocks glucagon-mediated inhibition of the liver plasma membrane (Ca2+-Mg2+)-ATPase 总被引:2,自引:0,他引:2
S Lotersztajn C Pavoine A Mallat D Stengel P A Insel F Pecker 《The Journal of biological chemistry》1987,262(7):3114-3117
We have previously shown that liver plasma membrane (Ca2+-Mg2+)-ATPase activity is inhibited by glucagon. To investigate the possible involvement of a GTP-binding (G) protein in this regulation, we have examined the effects of pertussis toxin and cholera toxin on inhibition of (Ca2+-Mg2+)-ATPase by glucagon. Treatment of liver plasma membranes with pertussis toxin did not affect the sensitivity of (Ca2+-Mg2+)-ATPase to the hormone. In contrast, treatment of plasma membranes or prior injection of animals with cholera toxin prevented inhibition of the (Ca2+-Mg2+)-ATPase by glucagon. Even though adenylate cyclase activity was increased by cholera toxin treatment, addition of cyclic AMP did not mimic the effect of cholera toxin in blocking glucagon-mediated inhibition of (Ca2+-Mg2+)-ATPase activity. These data suggest that a cholera toxin-sensitive protein, perhaps Gs or a Gs-like protein, is involved in the regulation of liver (Ca2+-Mg2+)-ATPase activity. The results emphasize the possible role of Gs-like proteins in regulation of enzymes other than adenylate cyclase and suggest that the study of (Ca2+-Mg2+)-ATPase may provide a useful enzymatic system to examine such regulation. 相似文献
2.
D. Stengel J. Parma M. -H. Gannagé N. Roeckel M. -G. Mattei R. Barouki J. Hanoune 《Human genetics》1992,90(1-2):126-130
Summary Recently, we characterized a cDNA clone that encodes a human brain adenylyl cyclase (HBAC1). In the present study, we identified a second population of mRNA suspected to encode a new brain adenylyl cyclase (HBAC2). The amino acid sequence of HBAC2 displays significant homology with HBAC1 in the highly conserved adenylyl cyclase domain (250 aminio acids), found in the 3 cytoplasmic domain of all mammalian adenylyl cyclases. However, outside this domain, the homology is extremely low, suggesting that the corresponding mRNA originates from a different gene. We report here the first chromosomal localization of the adenylyl cyclase genes determined by in situ hybridization of human metaphase chromosomal spreads using human brain cDNA probes specific for each mRNA. The probe corresponding to HBAC1 exhibited a strong specific signal on chromosome 8q24, with a major peak in the band q24.2. In contrast, the HBAC2 probe hybridized to chromosome 5p15, with a major peak in the band p15.3. The two cDNAs hybridized at the two loci without any cross reactivity. Thus, in human brain, a heterogeneous population of adenylyl cyclase mRNAs is expressed, and the corresponding genes might be under the control of independent regulatory mechanisms.Abbreviations C
catalytic part of adenylyl cyclase
- BBAC
bovine brain
- HBAC
human brain
- ROAC
rat olfactory
- RLAC
rat liver
- RTAC
rat testis adenylyl cyclase
- G
guanine nucleotide GTP binding protein (s, stimulatory; i, inhibitory) 相似文献
3.
Michael J. Sofia William T. Jackson Davis L. SaussyJr. Steven A. Silbaugh Larry L. Froelich Sandra L. Cockerham Peter W. Stengel 《Bioorganic & medicinal chemistry letters》1992,2(12)
A series of
-alkoxyphenols containing a tetrazole acid sidechain have been prepared as antagonists of leukotriene B4 receptors. These compounds were tested as receptor antagonists of human neutrophil and guinea pig lung membrane leukotriene B4 receptors. Compounds in this series were found to be up to 18-fold more potent than LY255283. These results indicate that the acyl group of the 1,2,4,5 substituted hydroxyacetophenone class of LTB4 antagonists is not critical to antagonist potency. 相似文献
4.
Peter W. Stengel Penelope A. Pechous Steven A. Silbaugh 《Prostaglandins & other lipid mediators》1987,33(4)
Exposure of conscious guinea pigs to A23187 aerosol produced a concentration-related increase of excised lung gas volume (ELGV),
.
., postmortem pulmonary gas trapping. Measurements of ELGV were highly correlated with
measurements of dynamic compliance (Cdyn) and total pulmonary resistance (RL) and were used as an indication of
airway obstruction. We pretreated guinea pigs intravenously with the following drugs: atropine; LY163443, a selective LTD4/E4 antagonist; indomethacin; propranolol; and pyrilamine. The guinea pigs were exposed for 8 minutes to the A23187 aerosol, and ELGV measurements were then made. Atropine or pyrilamine prevented the A23187-induced gas trapping. Indomethacin or propranolol tended to potentiate the response and when combined, they potentiated the gas trapping by 80%. LY163443 had no effect alone, but when combined with indomethacin, propranolol, and pyrilamine, inhibited A23187-induced gas trapping by 67%. We conclude that cholinergic and histaminergic mechanisms play major roles in the ionophore-induced pulmonary gas trapping of the guinea pig. With appropriate pretreatment, sulfidopeptide leukotrienes may produce a substantial effect. 相似文献
5.
Maintenance of the cellobiose utilization genes of Escherichia coli in a cryptic state 总被引:6,自引:1,他引:5
The genes for cellobiose utilization are normally cryptic in Escherichia
coli. The cellobiose system was used as a model to understand the process
by which silent genes are maintained in microbial populations. Previously
reported was (1) the isolation of a mutant strain that expresses the
cellobiose-utilization (Cel) genes and (2) that expression of those genes
allows utilization of three beta- glucoside sugars: cellobiose, arbutin,
and salicin. The Cel gene cluster has now been cloned from that mutant
strain. In the course of locating the Cel genes within the cloned DNA
segment, it was discovered that inactivation of the Cel-encoded hydrolase
rendered the host strain sensitive to all three beta-glucosides as potent
inhibitors. This sensitivity arises from the accumulation of the
phosphorylated beta- glucosides. Because even the fully active genes
conferred some degree of beta-glucoside sensitivity, the effects of
cellobiose on a series of five Cel+ mutants of independent origin were
investigated. Although each of those strains utilizes cellobiose as a sole
carbon and energy source, cellobiose also acts as a potent inhibitor that
reduces the growth rate on glycerol 2.5-16.5-fold. On the other hand,
wild-type strains that cannot utilize cellobiose are not inhibited. The
observation that the same compound can serve either as a nutrient or as an
inhibitor suggests that, under most conditions in which cellobiose will be
present together with other resources, there is a strong selective
advantage to having the cryptic (Cel0) allele. In those environments in
which cellobiose is the sole, or the best, resource, mutants that express
the genes (Cel+) will have a strong selective advantage. It is suggested
that temporal alternation between these two conditions is a major factor in
the maintenance of these genes in E. coli populations. This alternation of
environments and fitnesses was predicted by the model for cryptic-gene
maintenance that was previously published.
相似文献
6.
Eberhard Stengel 《Plant biology (Stuttgart, Germany)》1970,83(11):589-606
- 1 . Es werden Anlagentypen für die autotrophe, mixotrophe oder heterotrophe Saubere Kultur von Mikroalgen sowie Verfahren der Algenkultur auf Abwasserbasis beschrieben. Zur Erstellung von Freilandanlagen erscheinen Beckenkonstruktionen besonders geeignet, die auf die Verwendung industrieller Fertigteile abgestellt sind. Bei der autotrophen Kultur von Mikroalgen im Freiland besteht das Hauptproblem darin, einen effizienten CO2-Eintrag zu erzielen
- 2 . Massenkulturen mariner und limnischer Mikroalgen haben vor allem in Japan als Komponenten komplexer Aquakultursysteme wirtschaftliche Bedeutung erlangt
- 3 . Besonderes Interesse verdienen Verfahren zur Massenkultur von Mikroalgen in Abwässern. Mit ihrer Hilfe gelingt es, auf verhältnismäßig engem Raum hohe Abbauleistungen der organischen Fracht zu erzielen und gleichzeitig proteinreiche Substanz für die Tierernährung zu produzieren
7.
Lung degassing: an evaluation of two methods 总被引:1,自引:0,他引:1
8.
9.
E. Stengel 《BMJ (Clinical research ed.)》1965,1(5451):1667-1668