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11.
A reliable estimation of the efficiency of adding homopolymeric tails to double-stranded cDNA molecules by terminal deoxynucleotidyl transferase is extremely important in the construction of cDNA libraries. Appreciable differences in transformation efficiency result when the homopolymer tails to be annealed are of inadequate length. We report here that the use of a Sephadex G-50 spun column to remove oligo(dT)12-18 frequently coprecipitating in ethanol with the cDNA results in a more dependable estimation of tail lengths. 相似文献
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Intracellular protein catabolism: state of the art 总被引:7,自引:0,他引:7
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Gruber Véronique Berna Patrick P. Arnaud Thierry Bournat Philippe Clément Christèle Mison Dominique Olagnier Béatrice Philippe Laurence Theisen Manfred Baudino Sylvie Bénicourt Claude Cudrey Claire Bloës Carole Duchateau Nathalie Dufour Sylvie Gueguen Catherine Jacquet Séverine Ollivo Catherine Poncetta Christine Zorn Nathalie Ludevid Dolores Van Dorsselaer Alain Verger Robert Doherty Annette Mérot Bertrand Danzin Charles 《Molecular breeding : new strategies in plant improvement》2001,7(4):329-340
A recombinant dog gastric lipase with therapeutic potential for the treatment of exocrine pancreatic insufficiency was expressed in transgenic tobacco plants. We targeted the protein using two different signal sequences for either vacuolar retention or secretion. In both cases, an active glycosylated recombinant protein was obtained. The recombinant enzymes and the native enzyme displayed similar properties including acid resistance and acidic optimum pH. The proteolytic maturation and the specific activity of the recombinant proteins, however, were found to be dependent on subcellular compartmentalization. Expression levels of recombinant dog gastric lipase were about 5% and 7% of acid extractable plant proteins for vacuolar retention and secretion respectively. This expression system already has allowed the production of tens of grams of purified lipase through open-field culture of transgenic tobacco plants. 相似文献
15.
T. K. McCarthy P. Frankiewicz P. Cullen M. Blaszkowski W. O’Connor D. Doherty 《Hydrobiologia》2008,609(1):109-124
The Shannon, Ireland’s largest river, is used for hydroelectricity generation since 1929. Subsequently, the Electricity Supply
Board assumed responsibility for management of its eel stocks, due to the impact of the hydro-dam on recruitment to the commercial
fishery. In order to negate a decline in juvenile recruitment resulting from the installation of hydroelectric facilities,
management was focused on stocking lakes with elvers and fingerling eels. These were trapped at the hydropower facilities
and in estuarine tributaries during their up-stream migrations. Due to the decline of natural recruitment in more recent times,
attempts have also been made to develop an estuarine glass eel fishery. Stock levels are then monitored through annual surveys
of the population trends of juvenile (glass eel, elver), growing phase (yellow eel) and downstream migrating pre-spawners
(silver eels). Survey results and fishery management programmes are reviewed in this article. In addition to the long-term
effects the hydroelectric facilities have had on the stock levels, there is also an annual effect on the migratory patterns
of downstream migratory silver eels. In the lower reaches of the river system flow rates are regulated by the hydroelectric
stations. We review previous work that had highlighted the importance of flow in determining the timing of the silver eels
migrations, and assess the relationship between flow and migration in more detail through the use of hydroacoustic and telemetric
studies. Current research on seaward migrating silver eel populations, suggests that spawner escapement rates can most effectively
be increased by trapping migrating eels at fishing weirs located up-stream of the power station and transporting them towards
the estuary.
Guest editors: R. L. Welcomme & G. Marmulla
Hydropower, Flood Control and Water Abstraction: Implications for Fish and Fisheries 相似文献
16.
Nitric oxide is a diffusible messenger that plays a multitude of roles within the nervous system including modulation of cell viability. However, its role in regulating neuronal survival during a defined period of neurodevelopment has never been investigated. We discovered that expression of the messenger RNA for both neuronal and endothelial nitric oxide synthase increased in the early postnatal period in the cerebellum in vivo, whilst the expression of inducible nitric oxide synthase remained constant throughout this time in development. Whilst scavenging of nitric oxide was deleterious to the survival of early postnatal cerebellar granule neurons in vitro, this effect was lost in cultures derived at increasing postnatal ages. Conversely, sensitivity to exogenous nitric oxide increased with advancing postnatal age. Thus, we have shown that as postnatal development proceeds, cerebellar granule cells alter their in vitro survival responses to both nitric oxide inhibition and donation, revealing that the nitric oxide's effects on developing neurons vary with the stage of development studied. These findings have important consequences for our understanding of the role of nitric oxide during neuronal development. 相似文献
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Seamus Doherty Frédérik Saltré John Llewelyn Giovanni Strona Stephen E. Williams Corey J. A. Bradshaw 《Global Change Biology》2023,29(18):5122-5138
The biosphere is changing rapidly due to human endeavour. Because ecological communities underlie networks of interacting species, changes that directly affect some species can have indirect effects on others. Accurate tools to predict these direct and indirect effects are therefore required to guide conservation strategies. However, most extinction-risk studies only consider the direct effects of global change—such as predicting which species will breach their thermal limits under different warming scenarios—with predictions of trophic cascades and co-extinction risks remaining mostly speculative. To predict the potential indirect effects of primary extinctions, data describing community interactions and network modelling can estimate how extinctions cascade through communities. While theoretical studies have demonstrated the usefulness of models in predicting how communities react to threats like climate change, few have applied such methods to real-world communities. This gap partly reflects challenges in constructing trophic network models of real-world food webs, highlighting the need to develop approaches for quantifying co-extinction risk more accurately. We propose a framework for constructing ecological network models representing real-world food webs in terrestrial ecosystems and subjecting these models to co-extinction scenarios triggered by probable future environmental perturbations. Adopting our framework will improve estimates of how environmental perturbations affect whole ecological communities. Identifying species at risk of co-extinction (or those that might trigger co-extinctions) will also guide conservation interventions aiming to reduce the probability of co-extinction cascades and additional species losses. 相似文献
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M E Frankel R B Effros P C Doherty W U Gerhard 《Journal of immunology (Baltimore, Md. : 1950)》1979,123(5):2438-2440
A particular monoclonal antibody that binds to the influenza virus HA molecule inhibits HA-specific thymus-derived lymphocytes mediating cytotoxicity in the context of H-2Dd but not of H-2Kd. Another monoclonal antibody blocks both sets of HA-specific effector T cells. This observation, together with related findings from other laboratories, is considered to support the idea that T cell recognition is directed against some association of viral and H-2 glycoproteins, as proposed in the original formulation of the "altered self" concept. 相似文献