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211.
Nathalie Fenner Robert Williams Hannah Toberman Steve Hughes Brian Reynolds Chris Freeman 《Hydrobiologia》2011,665(1):51-66
The hypothesis that specific components of seawater, such as particulate, dissolved and colloidal organic and inorganic material,
render virions non-infective has long been postulated, but never rigorously tested. To address this hypothesis, the plaque
assay method was used to derive infective decay rates, k, of two bacteriophages—P1 (marine host: PWH3a) and T4 (enteric host: E. coli B). We compared k values of bacteriophage suspended in serial filtrations of seawater, with and without autoclaving and UV oxidation. Both
phages exhibited reduced decay rates in particle-free water (<0.2 μm) compared to <10 μm filtrate. The largest decrease in
virion decay rates was achieved by autoclaving the 0.2 μm filtrate. UV oxidation of <0.2 μm filtrate, however, yielded higher
decay rates than observed in autoclaved treatments. The lowest k values were seen in ultra-filtered seawater (<10 kDa). Exposure to a wide range of concentrations of Pronase E (a proteolytic
enzyme), inorganic clay (kaolinite or montmorillonite), and organic particles (phytoplankton debris) did not promote phage
inactivation. P1 infective titers were also not consistently reduced by exposures to axenic cultures of a resistant host mutant
(PWH3a-R) and a non-host marine bacterium (MB-5). Finally, phage were exposed to a range of temperatures to derive activation
energies required for phage inactivation. Application of the Arrhenius model to inactivation of T4 and P1 yielded activation
energies (E
a) of 49 and 40 kJ mol−1, respectively. This is the first comprehensive analysis in which specific seawater components were assayed for their ability
to inactivate bacteriophage. Inactivation of these phage does not appear to depend on capsomere denaturation, proteolytic
extracellular enzymes, sorption to non-host bacteria, clay particles or particulate organic debris, but is accelerated by
naturally occurring particles, which include living organisms, and heat-labile colloids and macromolecules >10 kDa. 相似文献
212.
Susanna-Assunta Sansone Daniel Schober Helen J. Atherton Oliver Fiehn Helen Jenkins Philippe Rocca-Serra Denis V. Rubtsov Irena Spasic Larisa Soldatova Chris Taylor Andy Tseng Mark R. Viant 《Metabolomics : Official journal of the Metabolomic Society》2007,3(3):249-256
In this article we present the activities of the Ontology Working Group (OWG) under the Metabolomics Standards Initiative
(MSI) umbrella. Our endeavour aims to synergise the work of several communities, where independent activities are underway
to develop terminologies and databases for metabolomics investigations. We have joined forces to rise to the challenges associated
with interpreting and integrating experimental process and data across disparate sources (software and databases, private
and public). Our focus is to support the activities of the other MSI working groups by developing a common semantic framework
to enable metabolomics-user communities to consistently annotate the experimental process and to enable meaningful exchange
of datasets. Our work is accessible via a public webpage and a draft ontology has been posted under the Open Biological Ontology
umbrella. At the very outset, we have agreed to minimize duplications across omics domains through extensive liaisons with
other communities under the OBO Foundry. This is work in progress and we welcome new participants willing to volunteer their
time and expertise to this open effort.
See the MSI Ontology Working Group website for a complete list of members and contributors. Web URL: 相似文献
213.
214.
We analyzed long-term winter survey data (1956–2007) for three endangered waterbirds endemic to the Hawaiian Islands, the
Hawaiian moorhen (Gallinula chloropus sandvicensis), Hawaiian coot (Fulica alai), and Hawaiian stilt (Himantopus mexicanus knudseni). Time series were analyzed by species–island combinations using generalized additive models, with alternative models compared
using Akaike information criterion (AIC). The best model included three smoothers, one for each species. Our analyses show
that all three of the endangered Hawaiian waterbirds have increased in population size over the past three decades. The Hawaiian
moorhen increase has been slower in more recent years than earlier in the survey period, but Hawaiian coot and stilt numbers
still exhibit steep increases. The patterns of population size increase also varied by island, although this effect was less
influential than that between species. In contrast to earlier studies, we found no evidence that rainfall affects counts of
the target species. Significant population increases were found on islands where most wetland protection has occurred (Oahu,
Kauai), while weak or no increases were found on islands with few wetlands or less protection (Hawaii, Maui). Increased protection
and management, especially on Maui where potential is greatest, would likely result in continued population gains, increasing
the potential for meeting population recovery goals. 相似文献
215.
Michael B. Clark Paulo P. Amaral Felix J. Schlesinger Marcel E. Dinger Ryan J. Taft John L. Rinn Chris P. Ponting Peter F. Stadler Kevin V. Morris Antonin Morillon Joel S. Rozowsky Mark B. Gerstein Claes Wahlestedt Yoshihide Hayashizaki Piero Carninci Thomas R. Gingeras John S. Mattick 《PLoS biology》2011,9(7)
216.
Understanding, and therefore measuring, factors that determine fitness is a central problem in evolutionary biology. We studied a natural population of Coenagrion puella (Odonata: Zygoptera) over two entire breeding seasons, with over a thousand individuals uniquely marked and genotyped, and all mating events at the rendezvous site recorded. Using a parentage analysis, fitness of individuals in the first generation was quantified as the numbers of offspring that survived to maturity. Although mating behaviour can be predicted by environmental and demographical variables, the numbers of mature offspring produced (fitness) cannot, and crucially, are poorly correlated with behavioural observations of mating. While fitness of both sexes was positively related to mating behaviour and to female's ectoparasite burden, these behavioural observations explained little more variance in offspring production than environmental and demographical variables. Thus, we demonstrate that behavioural measures of reproductive success are not necessarily reliable estimates of fitness in natural populations. 相似文献
217.
218.
V. Alex Sotola David S. Ruppel Timothy H. Bonner Chris C. Nice Noland H. Martin 《Ecology and evolution》2019,9(4):2083-2095
When ecologically divergent taxa encounter one another, hybrid zones can form when reproductive isolation is incomplete. The location of such hybrid zones can be influenced by environmental variables, and an ecological context can provide unique insights into the mechanisms by which species diverge and are maintained. Two ecologically differentiated species of small benthic fishes, the endemic and imperiled prairie chub, Macrhybopsis australis, and the shoal chub, Macrhybopsis hyostoma, are locally sympatric within the upper Red River Basin of Texas. We integrated population genomic data and environmental data to investigate species divergence and the maintenance of species boundaries in these two species. We found evidence of advanced‐generation asymmetric hybridization and introgression, with shoal chub alleles introgressing more frequently into prairie chubs than the reciprocal. Using a Bayesian Genomic Cline framework, patterns of genomic introgression were revealed to be quite heterogeneous, yet shoal chub alleles were found to have likely selectively introgressed across species boundaries significantly more often than prairie chub alleles, potentially explaining some of the observed asymmetry in hybridization. These patterns were remarkably consistent across two sampled geographic regions of hybridization. Several environmental variables were found to significantly predict individual admixture, suggesting ecological isolation might maintain species boundaries. 相似文献
219.
220.
Using haplotypes to monitor the migration of fall armyworm (Lepidoptera: Noctuidae) corn-strain populations from Texas and Florida 总被引:4,自引:0,他引:4
Nagoshi RN Meagher RL Flanders K Gore J Jackson R Lopez J Armstrong JS Buntin GD Sansone C Leonard BR 《Journal of economic entomology》2008,101(3):742-749
Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), infestations in most of North America north of Mexico arise from annual migrations of populations that overwinter in southern Texas and Florida. A comparison of the cytochrome oxidase I haplotype profiles within the fall armyworm corn-strain, the subgroup that preferentially infests corn (Zea mays L.) and sorghum (Sorghum vulgare Pers.), identified significant differences in the proportions of certain haplotypes between the Texas and Florida populations. These proportional differences were preserved as the populations migrated, providing a molecular metric by which the source of a migrant population could be identified. The migratory pattern derived from this method for several southeastern states was shown to be consistent with predictions based on analysis of historical agricultural and fall armyworm infestation data. These results demonstrate the utility of haplotype proportions to monitor fall armyworm migration, and they also introduce a potential method to predict the severity of cotton crop infestations in the short term. 相似文献