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Decroly E Debarnot C Ferron F Bouvet M Coutard B Imbert I Gluais L Papageorgiou N Sharff A Bricogne G Ortiz-Lombardia M Lescar J Canard B 《PLoS pathogens》2011,7(5):e1002059
Cellular and viral S-adenosylmethionine-dependent methyltransferases are involved in many regulated processes such as metabolism, detoxification, signal transduction, chromatin remodeling, nucleic acid processing, and mRNA capping. The Severe Acute Respiratory Syndrome coronavirus nsp16 protein is a S-adenosylmethionine-dependent (nucleoside-2'-O)-methyltransferase only active in the presence of its activating partner nsp10. We report the nsp10/nsp16 complex structure at 2.0 ? resolution, which shows nsp10 bound to nsp16 through a ~930 ?2 surface area in nsp10. Functional assays identify key residues involved in nsp10/nsp16 association, and in RNA binding or catalysis, the latter likely through a SN2-like mechanism. We present two other crystal structures, the inhibitor Sinefungin bound in the S-adenosylmethionine binding pocket and the tighter complex nsp10(Y96F)/nsp16, providing the first structural insight into the regulation of RNA capping enzymes in +RNA viruses. 相似文献
954.
This study reports a novel form of interference behaviour between the invasive wasp Vespula vulgaris and the New Zealand native ant Prolasius advenus. By videotaping interactions at bait stations, we found that wasps commonly remove ant competitors from food resources by picking up the workers in their mandibles, flying backward and dropping them unharmed some distance from the food. Both the frequency and the efficiency of the wasp behaviour significantly increased with the abundance of ant competitors. Ant removals were the most common interference events initiated by wasps when ants were numerous, while intraspecific conflicts among wasps were prominent when few ants were present. The 'ant-dropping' behaviour emphasizes how asymmetry in body sizes between competitors can lead to a pronounced form of interference, related to asymmetric locomotion modes. 相似文献
955.
The significance threshold for coherence when using the Welch's periodogram method: Effect of overlapping segments 总被引:1,自引:0,他引:1
A classical tool to identify coupling mechanisms between two biological signals is transfer function (TF) analysis, commonly estimated by the Welch's periodogram method. However, the reliability of TF estimation depends on the coherence function, an index of linear coupling in the frequency domain. Thus, a threshold value has to be determined before assuming a coupling between two signals at a given frequency.Koopmans (The spectral analysis of time series) proposed a theoretical expression in the case of non-overlapping segments. Overlapping segments, however, improves the estimation of TF.In the present study, a modification of the expression by Koopmans is proposed for taking into account the effect of the overlapping procedure, including the most common case of a 50% overlapping ratio. Simulation tests were done on non-coherent signals (using the Hanning window), and a Kolmogorov–Smirnov test was used to check for the adequacy with the proposed threshold formula. The results showed that for an overlapping ratio of 50%, no statistical difference could be found (P > 0.05), except when using less than seven segments.The method has been applied to the computation of the transfer function between systolic blood pressure and heart rate. 相似文献
956.
Rowe KC Singhal S Macmanes MD Ayroles JF Morelli TL Rubidge EM Bi K Moritz CC 《Molecular ecology resources》2011,11(6):1082-1092
Natural history collections are unparalleled repositories of geographical and temporal variation in faunal conditions. Molecular studies offer an opportunity to uncover much of this variation; however, genetic studies of historical museum specimens typically rely on extracting highly degraded and chemically modified DNA samples from skins, skulls or other dried samples. Despite this limitation, obtaining short fragments of DNA sequences using traditional PCR amplification of DNA has been the primary method for genetic study of historical specimens. Few laboratories have succeeded in obtaining genome-scale sequences from historical specimens and then only with considerable effort and cost. Here, we describe a low-cost approach using high-throughput next-generation sequencing to obtain reliable genome-scale sequence data from a traditionally preserved mammal skin and skull using a simple extraction protocol. We show that single-nucleotide polymorphisms (SNPs) from the genome sequences obtained independently from the skin and from the skull are highly repeatable compared to a reference genome. 相似文献
957.
Muscodor albus (Xylariaceae, Ascomycetes) isolate CZ-620 produces antimicrobial volatile organic?compounds (VOC), which appear to have potential for the control of various postharvest diseases. The effect of water activity (Aw) on the production of VOC by M. albus culture, and their inhibitory effects on the growth of three pathogens of potato tuber (Fusarium sambucinum, Helminthosporium solani, and Pectobacterium atrosepticum) and the development of diseases caused by the three pathogens (dry rot, silver scurf, and bacterial soft rot, respectively)?were investigated. Rye grain culture of the fungus produced six alcohols, three aldehydes, five acids or esters, and two terpenoids. The most abundant VOC were: isobutyric acid; bulnesene, a sesquiterpene; an unidentified terpene; 2 and 3-methyl-1-butanol; and ethanol. However, the level of each of those VOC varied with Aw of the culture. Emission activity?occurred mainly at Aw above 0.75 and high emission of most VOC occurred only at Aw above 0.90. The aldehydes (2-methyl-propanal and 3-methyl-butanal) were the only VOC produced in quantities below an Aw of 0.90. An Aw value of 0.96 favored maximum emission of acids, esters, and terpenoids. There was a higher production of alcohols and a decrease in aldehydes with increase in Aw. Isobutyric acid, which has been the main M.?albus VOC monitored in previous studies as an indicator of antifungal activity, had a rather narrow optimum, peaking at Aw of 0.96 and declining sharply above 0.98. Results showed that substrate Aw affects the production dynamics of each group of VOC by the fungus, and suggest that VOC production can be prolonged by maintaining M. albus culture at a constant optimum Aw. The VOC was inhibitory to F. sambucinum, H. solani, and P. atrosepticum; and biofumigation with M. albus significantly reduced dry rot and soft rot development, and completely controlled silver scurf in inoculated tubers incubated at both 8°C and 22°C. The results show that Aw of grain culture affects the production of VOC by M.?albus; and that the VOC inhibit the growth of the tested pathogens and the diseases caused by them in potato?tubers. 相似文献
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Vande Velde C McDonald KK Boukhedimi Y McAlonis-Downes M Lobsiger CS Bel Hadj S Zandona A Julien JP Shah SB Cleveland DW 《PloS one》2011,6(7):e22031
Mutations in superoxide dismutase (SOD1) are causative for inherited amyotrophic lateral sclerosis. A proportion of SOD1 mutant protein is misfolded onto the cytoplasmic face of mitochondria in one or more spinal cord cell types. By construction of mice in which mitochondrially targeted enhanced green fluorescent protein is selectively expressed in motor neurons, we demonstrate that axonal mitochondria of motor neurons are primary in vivo targets for misfolded SOD1. Mutant SOD1 alters axonal mitochondrial morphology and distribution, with dismutase active SOD1 causing mitochondrial clustering at the proximal side of Schmidt-Lanterman incisures within motor axons and dismutase inactive SOD1 producing aberrantly elongated axonal mitochondria beginning pre-symptomatically and increasing in severity as disease progresses. Somal mitochondria are altered by mutant SOD1, with loss of the characteristic cylindrical, networked morphology and its replacement by a less elongated, more spherical shape. These data indicate that mutant SOD1 binding to mitochondria disrupts normal mitochondrial distribution and size homeostasis as early pathogenic features of SOD1 mutant-mediated ALS. 相似文献
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