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排序方式: 共有141条查询结果,搜索用时 15 毫秒
1.
Francisco Javier Caballero Isabel Igeño Jacobo Cárdenas Francisco Castillo 《Archives of microbiology》1989,152(5):508-511
The phototrophic bacterium Rhodobacter capsulatus E1F1 assimilates ammonia and other forms of reduced nitrogen either through the GS/GOGAT pathway or by the concerted action of l-alanine dehydrogenase and aminotransferases. These routes are light-independent and very responsive to the carbon and nitrogen sources used for cell growth. GS was most active in cells grown on nitrate or l-glutamate as nitrogen sources, whereas it was heavily adenylylated and siginificantly repressed by ammonium, glycine, l-alanine, l-aspartate, l-asparagine and l-glutamine, under which conditions specific aminotransferases were induced. GOGAT activity was kept at constitutive levels in cells grown on l-amino acids as nitrogen sources except on l-glutamine where it was significantly induced during the early phase of growth. In vitro, GOGAT activity was strongly inhibited by l-tyrosine and NADPH. In cells using l-asparagine or l-aspartate as nitrogen source, a concerted induction of l-aspartate aminotransferase and l-asparaginase was observed. Enzyme level enhancements in response to nitrogen source variation involved de novo protein synthesis and strongly correlated with the cell growth phase.Abbreviations ADH
l-alanine dehydrogenase
- AOAT
l-alanine:2-oxoglutarate aminotransferase
- Asnase
l-asparaginase
- GOAT
Glycine: oxaloacetate aminotransferase
- GOGAT
Glutamate synthase
- GOT
l-aspartate: 2-oxoglutarate aminotransferase
- GS
Glutamine synthetase
- HPLC
High-Pressure Liquid Chromatography
- MOPS
2-(N-morpholino)propanesulfonic acid
- MSX
l-methionine-d,l-sulfoximine 相似文献
2.
Andrzej Slominski Alexander Pisarchik Igor Semak Trevor Sweatman Jacobo Wortsman 《European journal of biochemistry》2003,270(16):3335-3344
We showed expression of the tryptophan hydroxylase gene and of tryptophan hydroxylase protein immunoreactivity in mouse skin and skin cells. Extracts from skin and melanocyte samples acetylated serotonin to N-acetylserotonin and tryptamine to N-acetyltryptamine. A different enzyme from arylalkylamine N-acetyltransferase mediated this reaction, as this gene was defective in the C57BL6 mouse, coding predominantly for a protein without enzymatic activity. Serotonin (but not tryptamine) acetylation varied according to hair cycle phase and anatomic location. Serotonin was also metabolized to 5-hydroxytryptophol and 5-hydroxyindole acetic acid, probably through stepwise transformation catalyzed by monoamine oxidase, aldehyde dehydrogenase and aldehyde reductase. Activity of the melatonin-forming enzyme hydroxyindole-O-methyltransferase was notably below detectable levels in all samples of mouse corporal skin, although it was detectable at low levels in the ears and in Cloudman melanoma (derived from the DBA/2 J mouse strain). In conclusion, mouse skin has the molecular and biochemical apparatus necessary to produce and metabolize serotonin and N-acetylserotonin, and its activity is determined by topography, physiological status of the skin, cell type and mouse strain. 相似文献
3.
Augusto García Villanueva María Jesús García Villanueva Mercedes García Villanueva Roberto Rojo Blanco María Vicenta Collado Guirao Jacobo Cabañas Montero Rafael Beni Pérez Irene Moreno Montes 《Endocrinología y nutrición》2013,60(5):254-259
Amyloidosis is an uncommon syndrome consisting of a number of disorders having in common an extracellular deposit of fibrillary proteins. This results in functional and structural changes in the affected organs, depending on deposit location and severity.Amyloid infiltration of the thyroid gland may occur in 50% and up to 80% of patients with primary and secondary amyloidosis respectively. Amyloid goiter (AG) is a true rarity, usually found associated to secondary amyloidosis. AG may require surgical excision, usually because of compressive symptoms.We report the case of a patient with a big AG occurring in the course of a secondary amyloidosis associated to polyarticular onset juvenile idiopathic arthritis who underwent total thyroidectomy. Current literature is reviewed, an attempt is made to provide action guidelines, and some surgical considerations on this rare condition are given. 相似文献
4.
Alba M. Franco‐Pereira Jacobo de Uña‐Álvarez 《Biometrical journal. Biometrische Zeitschrift》2013,55(1):52-67
In this paper, we introduce a new estimator of a percentile residual life function with censored data under a monotonicity constraint. Specifically, it is assumed that the percentile residual life is a decreasing function. This assumption is useful when estimating the percentile residual life of units, which degenerate with age. We establish a law of the iterated logarithm for the proposed estimator, and its ‐equivalence to the unrestricted estimator. The asymptotic normal distribution of the estimator and its strong approximation to a Gaussian process are also established. We investigate the finite sample performance of the monotone estimator in an extensive simulation study. Finally, data from a clinical trial in primary biliary cirrhosis of the liver are analyzed with the proposed methods. One of the conclusions of our work is that the restricted estimator may be much more efficient than the unrestricted one. 相似文献
5.
The diet of Perla madritensis, endemic species of the northern half of the Iberian Peninsula, is described for the first time by means of a study carried out in north-western Spain. As other species of the genus Perla, this taxon behaves mainly as predator, with Chironomidae, followed by Baetidae, being the most abundant prey in its gut. Shifts in diet composition were detected in relation to size in this species, with smaller prey being replaced by larger ones such as Simuliidae and Leptophlebiidae when the nymphs become larger. 相似文献
6.
Amy M. Van Cise Robin W. Baird Charles Scott Baker Salvatore Cerchio Diane Claridge Russell Fielding Brittany Hancock‐Hanser Jacobo Marrero Karen K. Martien Antonio A. Mignucci‐Giannoni Erin M. Oleson Marc Oremus M. Michael Poole Patricia E. Rosel Barbara L. Taylor Phillip A. Morin 《Molecular ecology》2019,28(11):2886-2902
Genomic phylogeography plays an important role in describing evolutionary processes and their geographic, ecological, or cultural drivers. These drivers are often poorly understood in marine environments, which have fewer obvious barriers to mixing than terrestrial environments. Taxonomic uncertainty of some taxa (e.g., cetaceans), due to the difficulty in obtaining morphological data, can hamper our understanding of these processes. One such taxon, the short‐finned pilot whale, is recognized as a single global species but includes at least two distinct morphological forms described from stranding and drive hunting in Japan, the “Naisa” and “Shiho” forms. Using samples (n = 735) collected throughout their global range, we examine phylogeographic patterns of divergence by comparing mitogenomes and nuclear SNP loci. Our results suggest three types within the species: an Atlantic Ocean type, a western/central Pacific and Indian Ocean (Naisa) type, and an eastern Pacific Ocean and northern Japan (Shiho) type. mtDNA control region differentiation indicates these three types form two subspecies, separated by the East Pacific Barrier: Shiho short‐finned pilot whale, in the eastern Pacific Ocean and northern Japan, and Naisa short‐finned pilot whale, throughout the remainder of the species' distribution. Our data further indicate two diverging populations within the Naisa subspecies, in the Atlantic Ocean and western/central Pacific and Indian Oceans, separated by the Benguela Barrier off South Africa. This study reveals a process of divergence and speciation within a globally‐distributed, mobile marine predator, and indicates the importance of the East Pacific Barrier to this evolutionary process. 相似文献
7.
8.
Slominski AT Roloff B Zbytek B Wei ET Fechner K Curry J Wortsman J 《In vitro cellular & developmental biology. Animal》2000,36(3):211-216
Summary Following previous findings in human skin of the functional expression of genes for the corticotropin releasing hormone (CHR)
receptor type 1 (CRH-R1) and CRH itself, we searched for local phenotypic effects for peptides related to CRH. We now report
that CRH, sauvagine, and urocortin inhibit proliferation of human HaCaT keratinocytes in a dose-dependent manner. The peptides
produced variable cyclic adenosine 3′∶5′-monophosphate stimulation with CRH having the highest potency. Binding of iodine
125 CRH to intact keratinocytes was inhibited by increasing doses of CRH, sauvagine, or urocortin, all showing equal inhibitory
potency. Immunocytochemistry identified CRH-R1 immunoreactivity in HaCaT keratinocytes. In conclusion, CRH (exogenous or produced
locally) and the related urocortin and sauvagine peptides can modify human keratinocyte phenotype through a receptor-mediated
pathway. 相似文献
9.
10.
Viral Co-Infections in Pediatric Patients Hospitalized with Lower Tract Acute Respiratory Infections
Miriam Cebey-López Jethro Herberg Jacobo Pardo-Seco Alberto Gómez-Carballa Nazareth Martinón-Torres Antonio Salas José María Martinón-Sánchez Stuart Gormley Edward Sumner Colin Fink Federico Martinón-Torres GENDRES network 《PloS one》2015,10(9)