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441.
Ana LS Vanz Gaby Renard Mario S Palma Jocelei M Chies Sérgio L Dalmora Luiz A Basso Diógenes S Santos 《Microbial cell factories》2008,7(1):13
Background
Biopharmaceutical drugs are mainly recombinant proteins produced by biotechnological tools. The patents of many biopharmaceuticals have expired, and biosimilars are thus currently being developed. Human granulocyte colony stimulating factor (hG-CSF) is a hematopoietic cytokine that acts on cells of the neutrophil lineage causing proliferation and differentiation of committed precursor cells and activation of mature neutrophils. Recombinant hG-CSF has been produced in genetically engineered Escherichia coli (Filgrastim) and successfully used to treat cancer patients suffering from chemotherapy-induced neutropenia. Filgrastim is a 175 amino acid protein, containing an extra N-terminal methionine, which is needed for expression in E. coli. Here we describe a simple and low-cost process that is amenable to scaling-up for the production and purification of homogeneous and active recombinant hG-CSF expressed in E. coli cells. 相似文献442.
443.
The structural genes for human galactokinase (GALK) and the human cytosolic form of thymidine kinase (TK1) are located on
17q21–q22. These two loci are tightly linked, and studies on Chinese hamster cell lines have shown that the expression of
TK1 and GALK genes may alter simultaneously. We investigated the possibility of a dependent mutation of TK1 and GALK genes
in cultured fibroblasts obtained from two patients homozygous for the GALKG-deficient gene. Since we showed that the TK1 level varies as a function of the passage and the growth rate of a given strain,
our experiments were performed on nonstored skin fibroblasts, between the third and the fifth passage for both controls and
patients. We found that TK1 levels in GALK-deficient cells were almost 75% of those observed in control strains with a similar
growth rate. Previous results in the literature have shown a pronounced decrease in TK1 activity in three GALK-deficient fibroblastic
strains. We suggest that these disparities of TK1 levels in GALK-deficient fibroblasts may be related either to genetic heterogeneity
of GALK deficiency or to differences in culture conditions.
This work was supported in part by grants from La CNAMTS and l’Université de Paris-Sud (AI 86 10). 相似文献
444.
Influence of water chemistry and environmental degradation on macroinvertebrate assemblages in a river basin in south-east Brazil 总被引:6,自引:4,他引:2
Buss Daniel F. Baptista Darcílio F. Silveira Mariana P. Nessimian Jorge L. Dorvillé Luís F. M. 《Hydrobiologia》2002,481(1-3):125-136
Benthic macroinvertebrate assemblages, water chemistry variables and environmental degradation were investigated in an Atlantic Forest region in Brazil. Seven sites of the Guapimirim river basin were studied during three sampling periods based on the rain regime: end of wet season (May 1998), dry season (August 1998), and wet season (January 1999). Four substrates were collected at each site: sand, stony substrates, litter in pool areas and litter in riffle areas. Relationships between macroinvertebrate assemblages, water chemistry variables and environmental degradation were examined using canonical correspondence analysis (CCA). According to CCA, concentrations of dissolved oxygen and chloride, and the environmental degradation, measured by the Riparian Channel Environment index, exhibited the strongest relationship to macroinvertebrate assemblages. Overall, the loss of community diversity measured by the Shannon Index along the degradation gradient was observed. Some taxa were shown to be sensitive to water pollution, especially among Plecoptera, Trichoptera, Coleoptera and some Ephemeroptera, while others such as Simuliidae, Odonata and molluscs were tolerant to moderate levels of pollutants. The Chironomidae were the only group tolerant to a high level of pollutants and degradation. 相似文献
445.
The mammalian accessory olfactory bulb (AOB) is chemoarchitecturally
heterogeneous in that it stains differentially with a number of markers;
the receptor cells that project to the AOB are similarly heterogeneous.
What is the significance of this heterogeneity? We have found that the AOB
of the gray, short-tailed opossum, Monodelphis domestica, stains
differentially with a number of 'markers': antibodies to olfactory marker
protein (OMP) and the alpha subunit of the G protein Gi2, the lectin of
Vicia villosa and NADPH-diaphorase. These markers stain the rostral AOB
more strongly than the caudal AOB whereas, the G protein subunit G(o) alpha
is located predominantly in the posterior subdivision of the AOB. This
heterogeneity in the chemoarchitecture of the AOB may reflect a fundamental
organizational dichotomy within the vomeronasal system that corresponds to
a functional dichotomy. The vomeronasal sensory epithelium also exhibits a
chemoarchitectural heterogeneity: receptor cells in the basal third are
G(o) alpha-immunoreactive whereas the cells in the middle third are Gi2
alpha-immunoreactive. Tracing studies using WGA-HRP demonstrate that the
neurons in the middle third of the vomeronasal sensory epithelium project
their axons to the anterior AOB whereas those in the basal third appear to
project to the posterior AOB.
相似文献
446.
F. Martinho M. Dolbeth I. Viegas J. Baptista H. N. Cabral M. A. Pardal 《Zeitschrift fur angewandte Ichthyologie》2010,26(6):843-852
Temporal and spatial patterns of abundance of the flatfish community in the Mondego estuary were investigated from 2003 to 2007, based on monthly beam trawl samples. During the study period there was a severe drought, with consequential reductions in river runoff. A total of eight flatfish species occurred within the estuary, with seasonal specific richness and abundance varying considerably. It was possible to identify three main groups: one composed of species present throughout the study period and in high densities: Platichthys flesus and Solea solea (maximum densities 3.7 and 4.1 Ind 1000 m?2, respectively); a second group of less abundant but regularly present species: Scophthalmus rhombus and Solea senegalensis (maximum densities 0.2 and 0.3 Ind 1000 m?2, respectively); and a third group of occasional species that occurred only during the drought period: Arnoglossus laterna, Buglossidium luteum, Dicologlossa hexophthalma and Pegusa lascaris. Flatfish distribution patterns varied according to the estuarine use guild: marine‐estuarine dependent fish occurred mainly in the upper reaches, while marine stragglers and marine‐estuarine opportunists occurred mostly in the downstream areas. Species with more northern latitudinal affinities were the most affected by the drought, related with a lesser extent of river plumes to the coastal area, resulting in a reduction in half of the abundance levels. However, flatfish species with more southern affinities increased in abundance during the drought, benefiting also from an increase in estuarine water temperature. Early summer salinity and precipitation values were good proxies for estimating abundance levels of P. flesus and S. solea, respectively, emphasizing the importance of hydrodynamics for the recruitment and abundance of these commercially important species. 相似文献
447.
Iris Foroni Claudio Baptista Lisandra Monteiro Maria S. Lopes Duarte Mendon?a Mónica Melo Concei??o Carvalho Paulo Monjardino David J. H. Lopes Artur da Camara Machado 《Plant Systematics and Evolution》2012,298(7):1297-1313
The objective of this study was to exploit the molecular and morphological variability present in Malus domestica to clarify the confused characterization of apple plantations in the Azores. Most Azorean apples are grown in orchards. They are usually given a local name, and sometimes the same name is used for different cultivars and varieties which share morphology and should be known by different names. Two-hundred samples of apples cultivated in the Azores were analyzed by use of ten microsatellites. The total number of alleles per locus ranged from 10 to 24, with a mean of 15.2. Heterozygosity was high, reflecting the high variability of the samples. Expected heterozygosity varied within a narrow range, from 0.74 to 0.88, whereas observed heterozygosity ranged from 0.41 to 0.98. The high genetic variability contributed to the high discriminating power, which ranged between 0.84 and 0.93. These microsatellites were used to unambiguously discriminate most of the tested apple cultivars on the basis of their allelic profiles. The rooted UPGMA tree organized most of the samples into thirteen main clusters, often with high bootstrap values. We identified 60 synonyms and 32 homonyms among the samples. Moreover, it was possible to relate each individual to its originating population and detect likely parent–offspring groups. 相似文献
448.
Marina Granado e Sá B. B. Baptista L. S. Farah V. P. Leite F. P. Zanotto 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(3):313-321
Crustaceans present a very interesting model system to study the process of calcification and calcium (Ca2+) transport because of molting-related events and the deposition of CaCO3 in the new exoskeleton. Dilocarcinus pagei, a freshwater crab endemic to Brazil, was studied to understand Ca2+ transport in whole gill cells using a fluorescent probe. Cells were dissociated, all of the gill cell types were loaded with
fluo-3 and intracellular Ca2+ change was monitored by adding Ca as CaCl2 (0, 0.1, 0.25, 0.50, 1.0 and 5 mM), with a series of different inhibitors. For control gill cells, Ca2+ transport followed Michaelis–Menten kinetics with K
m = 0.42 ± 0.04 mM and V
max = 0.50 ± 0.02 μM (Ca2+ change × initial intracellular Ca−1 × 180 s−1; N = 14, r
2 = 0.99). Verapamil (a Ca2+ channel inhibitor) and amiloride (a Na+/Ca2+ exchanger [NCX] inhibitor) completely reduced intracellular Ca2+ transport, while nifedipine, another Ca2+ channel inhibitor, did not. Vanadate, a plasma membrane Ca2+-ATPase inhibitor (PMCA), increased intracellular Ca2+ in gill cells through a decrease in the efflux of Ca2+. Ouabain increased intracellular Ca2+, similar to the effect of KB-R, a specific NCX inhibitor for Ca2+ in the influx mode. Alterations in extracellular [Na] in the saline did not affect intracellular Ca2+ transport. Caffeine, responsible for inducing Ca release from sarcoplasmic reticulum in vertebrate muscle, increased intracellular
Ca2+ compared to control, suggesting an effect of this inhibitor in gill epithelial cells of Dilocarcinus pagei, probably through release of intracellular stores. We also demonstrate here that intracellular Ca2+ in gill cells of Dilocarcinus pagei was kept relatively constant in face of an extracellular Ca concentration of 50-fold, suggesting that crustaceans are able
to display Ca2+ homeostasis through various Ca2+ intracellular sequestration mechanisms and/or plasma membrane Ca2+ influx and outflux that are highly regulatory. In summary, studies using whole gill cells are an interesting approach for
working with real regulatory Ca2+ mechanisms in intact cells under physiological Ca levels (mM range), compared to earlier work using isolated vesicles of
various epithelial cells. 相似文献