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921.
We evaluated the effects of Leishmania spp infection on several
population parameters of Lutzomyia longipalpis sensu lato
andLutzomyia pseudolongipalpis, vectors of visceral leishmaniasis
in Venezuela, under experimental conditions during the first post-feeding period.
Females of both species were allowed to feed and engorge on a suspension of fresh
washed human red blood cells in foetal calf serum. These blood cells were either
non-infected or infected with one of the fourLeishmania spp strains
and were offered through a chicken skin membrane. The longevity, life expectancy and
the fecundity of uninfected flies were similar in both species, but the fertility was
significantly lower in uninfected Lu. longipalpis females. In all
cases, the infection of Lu. longipalpis and Lu.
pseudolongipalpis by the Leishmania strains resulted in
significant detrimental effects, which exerted a fitness cost expressed by reduced
survival and life expectancy, as well as decreased fertility and fecundity compared
with the control groups. Nevertheless, differences in these parameters were observed
between these vector species depending on whether they were infected with the
autochthonous Venezuelan Leishmania infantum strain (NESA) or the
Brazilian reference strain (PP75). The experimental data obtained agree with field
data on the natural infection of these vector species and the significance of this
scenario is discussed. 相似文献
922.
Grégory Arnal Géraldine Bastien Nelly Monties Anne Abot Véronique Anton Leberre Sophie Bozonnet Michael O'Donohue Claire Dumon 《Applied and environmental microbiology》2015,81(1):31-39
Biocatalysts are essential for the development of bioprocesses efficient for plant biomass degradation. Previously, a metagenomic clone containing DNA from termite gut microbiota was pinpointed in a functional screening that revealed the presence of arabinofuranosidase activity. Subsequent genetic and bioinformatic analysis revealed that the DNA fragment belonged to a member of the genus Bacteroides and encoded 19 open reading frames (ORFs), and annotation suggested the presence of hypothetical transporter and regulator proteins and others involved in the catabolism of pentose sugar. In this respect and considering the phenotype of the metagenomic clone, it was noted that among the ORFs, there are four putative arabinose-specific glycoside hydrolases, two from family GH43 and two from GH51. In this study, a thorough bioinformatics analysis of the metagenomic clone gene cluster has been performed and the four aforementioned glycoside hydrolases have been characterized. Together, the results provide evidence that the gene cluster is a polysaccharide utilization locus dedicated to the breakdown of the arabinan component in pectin and related substrates. Characterization of the two GH43 and the two GH51 glycoside hydrolases has revealed that each of these enzymes displays specific catalytic capabilities and that when these are combined the enzymes act synergistically, increasing the efficiency of arabinan degradation. 相似文献
923.
924.
Sebastian Schlafer Javier E. Garcia Matilde Greve Merete K. Raarup Bente Nyvad Irene Dige 《Applied and environmental microbiology》2015,81(4):1267-1273
pH in the extracellular matrix of bacterial biofilms is of central importance for microbial metabolism. Biofilms possess a complex three-dimensional architecture characterized by chemically different microenvironments in close proximity. For decades, pH measurements in biofilms have been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit the monitoring of horizontal pH gradients in biofilms in real time. Quantitative fluorescence microscopy can overcome these problems, but none of the hitherto employed methods differentiated accurately between extracellular and intracellular microbial pH and visualized extracellular pH in all areas of the biofilms. Here, we developed a method to reliably monitor extracellular biofilm pH microscopically with the ratiometric pH-sensitive dye C-SNARF-4, choosing dental biofilms as an example. Fluorescent emissions of C-SNARF-4 can be used to calculate extracellular pH irrespective of the dye concentration. We showed that at pH values of <6, C-SNARF-4 stained 15 bacterial species frequently isolated from dental biofilm and visualized the entire bacterial biomass in in vivo-grown dental biofilms with unknown species composition. We then employed digital image analysis to remove the bacterial biomass from the microscopic images and adequately calculate extracellular pH values. As a proof of concept, we monitored the extracellular pH drop in in vivo-grown dental biofilms fermenting glucose. The combination of pH ratiometry with C-SNARF-4 and digital image analysis allows the accurate monitoring of extracellular pH in bacterial biofilms in three dimensions in real time and represents a significant improvement to previously employed methods of biofilm pH measurement. 相似文献
925.
926.
The Increase in Maternal Expression of axin1 and axin2 Contribute to the Zebrafish Mutant Ichabod Ventralized Phenotype
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![点击此处可从《Journal of cellular biochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fabio Valenti Jessica Ibetti Yuko Komiya Melissa Baxter Anna Maria Lucchese Lauren Derstine Claudia Covaciu Valeria Rizzo Renza Vento Giuseppe Russo Marcella Macaluso Franco Cotelli Daniele Castiglia Cara J. Gottardi Raymond Habas Antonio Giordano Gianfranco Bellipanni 《Journal of cellular biochemistry》2015,116(3):418-430
927.
928.
Characterization of postdive recovery using sound recordings and its relationship to dive duration,exertion, and foraging effort of southern elephant seals (Mirounga leonina)
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![点击此处可从《Marine Mammal Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alexandre Génin Gaëtan Richard Joffrey Jouma'a Baptiste Picard Nory El Ksabi Jade Vacquié Garcia Christophe Guinet 《Marine Mammal Science》2015,31(4):1452-1470
It is notoriously difficult to measure physiological parameters in cryptic free‐ranging marine mammals. However, it is critical to understand how marine mammals manage their energy expenditure and their diving behavior in environments where the predation risks are low and where survival is mainly linked to capacities to maintain physiological homeostasis and energy budget balance. Elephant seals are top marine predators that dive deeply and continuously when at sea. Using acoustic recorders deployed on two postbreeding southern elephant seals (SES) females, we developed methods to automatically estimate breathing frequency at the surface. Using this method, we found that seals took successive identical breaths at high frequency (0.29 Hz) when recovering at the surface and that breath count was strongly related to postdive surfacing time. In addition, dive depth was the main factor explaining surfacing time through the effects of dive duration and total underwater swimming effort exerted. Finally, we found that recovery does not only occur over one dive timescale, but over a multidive time scale for one individual. The way these predators manage their recovery will determine how they respond to the change in oceanic water column structure in the future. 相似文献
929.
930.