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排序方式: 共有875条查询结果,搜索用时 15 毫秒
81.
Jaime Gutiérrez Cristian A. Droppelmann Osvaldo Contreras Chiaki Takahashi Enrique Brandan 《PloS one》2015,10(8)
Fibroblasts are critical for wound contraction; a pivotal step in wound healing. They produce and modify the extracellular matrix (ECM) required for the proper tissue remodeling. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a key regulator of ECM homeostasis and turnover. However, its role in wound contraction is presently unknown. Here we describe that Transforming growth factor type β1 (TGF-β1), one of the main pro-fibrotic wound-healing promoting factors, decreases RECK expression in fibroblasts through the Smad and JNK dependent pathways. This TGF-β1 dependent downregulation of RECK occurs with the concomitant increase of β1-integrin, which is required for fibroblasts adhesion and wound contraction through the activation of focal adhesion kinase (FAK). Loss and gain RECK expression experiments performed in different types of fibroblasts indicate that RECK downregulation mediates TGF-β1 dependent β1-integrin expression. Also, reduced levels of RECK potentiate TGF-β1 effects over fibroblasts FAK-dependent contraction, without affecting its cognate signaling. The above results were confirmed on fibroblasts derived from the Reck
+/- mice compared to wild type-derived fibroblasts. We observed that Reck
+/- mice heal dermal wounds more efficiently than wild type mice. Our results reveal a critical role for RECK in skin wound contraction as a key mediator in the axis: TGF-β1—RECK- β1-integrin. 相似文献
82.
The soluble tellurium oxyanion, tellurite, is toxic for most organisms. At least in part, tellurite toxicity involves the
generation of oxygen-reactive species which induce an oxidative stress status that damages different macromolecules with DNA,
lipids and proteins as oxidation targets. The objective of this work was to determine the effects of tellurite exposure upon
the Escherichia coli pyruvate dehydrogenase (PDH) complex. The complex displays two distinct enzymatic activities: pyruvate dehydrogenase that
oxidatively decarboxylates pyruvate to acetylCoA and tellurite reductase, which reduces tellurite (Te4+) to elemental tellurium (Teo). PDH complex components (AceE, AceF and Lpd) become oxidized upon tellurite exposure as a consequence of increased carbonyl
group formation. When the individual enzymatic activities from each component were analyzed, AceE and Lpd did not show significant
changes after tellurite treatment. AceF activity (dihydrolipoil acetyltransferase) decreased ~30% when cells were exposed
to the toxicant. Finally, pyruvate dehydrogenase activity decreased >80%, while no evident changes were observed in complex′s
tellurite reductase activity. 相似文献
83.
84.
Sepehr Bahadorani Jaehyoung Cho Thomas Lo Heidy Contreras Hakeem O. Lawal David E. Krantz Timothy J. Bradley David W. Walker 《Aging cell》2010,9(2):191-202
The ‘rate of living’ theory predicts that longevity should be inversely correlated with the rate of mitochondrial respiration. However, recent studies in a number of model organisms, including mice, have reported that interventions that retard the aging process are, in fact, associated with an increase in mitochondrial activity. To better understand the relationship between energy metabolism and longevity, we supplemented the endogenous respiratory chain machinery of the fruit fly Drosophila melanogaster with the alternative single‐subunit NADH–ubiquinone oxidoreductase (Ndi1) of the baker’s yeast Saccharomyces cerevisiae. Here, we report that expression of Ndi1 in fly mitochondria leads to an increase in NADH–ubiquinone oxidoreductase activity, oxygen consumption, and ATP levels. In addition, exogenous Ndi1 expression results in increased CO2 production in living flies. Using an inducible gene‐expression system, we expressed Ndi1 in different cells and tissues and examined the impact on longevity. In doing so, we discovered that targeted expression of Ndi1 in fly neurons significantly increases lifespan without compromising fertility or physical activity. These findings are consistent with the idea that enhanced respiratory chain activity in neuronal tissue can prolong fly lifespan. 相似文献
85.
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87.
Several species of bivalves coexist at the lower intertidal of large tidal flats located in the enclosed or inland coast of
the northern area of the Nord-Patagonic archipelagos on the Chilean coast (ca. 40–42°S): Tagelus dombeii (Lamarck), Mulinia edulis (King & Broderip), Venus antiqua King & Broderip, Semele solida (Gray), Gari solida (Gray) and Diplodonta insconspicua Philippi. To explore possible spatial variation in the community structure of the macroinfauna inhabiting sediments with
different assemblages of these bivalves, seasonal sampling was carried out during 2003–2004 at two tidal flats of that area.
Higher species richness and specimen densities of the macroinfauna occurred in sediments with the higher densities of bivalves,
especially in sediments where the deep burrower T. dombeii reaches its greatest abundances. Our results suggest that, apart from presence of bivalves, the burrowing depth of these
organisms is also important in promoting the abundance of macroinfauna. Our results are in contrast with earlier conceptualizations
for community organization of the soft bottom macroinfauna inhabiting intertidal flats, related to biological interactions
occurring among different phyletic groups, such as that arguing that suspension feeding bivalves (such as T. dombeii and V. antiqua) will negatively affect the recruitment of species with planktonic larvae, by filtering them before they become established
in the substrate. Thus, it is concluded that beneficial effects of bivalve bioturbation overcome that negative effects on
the macroinfauna, although detrimental effects may well occur at bivalve densities higher than those studied here.
Electronic supplementary material Supplementary material is available for this article at and accessible for authorised users 相似文献
88.
Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88 总被引:1,自引:0,他引:1
Pel HJ de Winde JH Archer DB Dyer PS Hofmann G Schaap PJ Turner G de Vries RP Albang R Albermann K Andersen MR Bendtsen JD Benen JA van den Berg M Breestraat S Caddick MX Contreras R Cornell M Coutinho PM Danchin EG Debets AJ Dekker P van Dijck PW van Dijk A Dijkhuizen L Driessen AJ d'Enfert C Geysens S Goosen C Groot GS de Groot PW Guillemette T Henrissat B Herweijer M van den Hombergh JP van den Hondel CA van der Heijden RT van der Kaaij RM Klis FM Kools HJ Kubicek CP van Kuyk PA Lauber J 《Nature biotechnology》2007,25(2):221-231
89.
María Lourdes Acosta Asterio Sánchez Francisco García Antonio Contreras Emilio Molina 《Cytotechnology》2007,54(3):189-200
Batch cultures were carried out to study the kinetic, stoichiometry, and regulation of glucose and glutamine metabolism of
a murine hybridoma line. Asymmetric logistic equations (ALEs) were used to fit total and viable cell density, and nutrient
and metabolite/product concentrations. Since these equations were analytically differentiable, specific rates and yield coefficients
were readily calculated. Asymmetric logistic equations described satisfactorily uncontrolled batch cultures, including death
phase. Specific growth rate showed a Monod-type dependence on initial glucose and glutamine concentrations. Yield coefficients
of cell and lactate from glucose, and cell and ammonium from glutamine were all found to change dramatically at low residual
glucose and glutamine concentrations. Under stoichiometric glucose limitation, the glucose-to-cell yield increased and glucose-to-lactate
yield decreased, indicating a metabolic shift. Under stoichiometric glutamine limitation the glutamine-to-cell and glutamine-to-ammonium
yields increased, but also glucose-to-cell yield increased and the glucose-to-lactate yield decreased. Monoclonal antibody
production was mainly non-growth associated, independently of glucose and glutamine levels. 相似文献
90.