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61.
Natácia Evangelista de Lima Alexandre Assis Carvalho Alan William Meerow Maura Helena Manfrin 《Organisms Diversity & Evolution》2018,18(2):151-161
The genus Acrocomia, popularly known as macaw palm or macaúba, occurs in savanna areas and open forests of tropical America, with distribution from Central to southern South America. They are important oleaginous palm trees, due to their role in ecosystems and local economies and their potential for biofuel production and vegetable oil. Although the taxonomy of the genus is not resolved because of observed phenotypic diversity in A. aculeata (Jacq.) Lodd. ex Mart., there are several conflicting treatments. Some authors recognize three caulescent spp. occurring in South America: A. aculeata, A. intumescens Drude, and A. totai Mart, although a new one was described recently—Acrocomia corumbaensis. Because some Latin American governments want to expand production of macaw palm in their territory as raw material for agro-energy, several groups have been encouraged to study this genus, focusing on the production of biodiesel, seed germination, phenotypic aspects, and genetic diversity. The goal of this review is to compile key information available in the literature and herbarium data, focusing on South American populations of the genus. 相似文献
62.
Large, rapidly evolving intergenic spacers in the mitochondrial DNA of the salamander family Ambystomatidae (Amphibia: Caudata) 总被引:5,自引:2,他引:3
We report the presence, in the mitochondrial DNA (mtDNA) of all of the
sexual species of the salamander family Ambystomatidae, of a shared 240- bp
intergenic spacer between tRNAThr and tRNAPro. We place the intergenic
spacer in context by presenting the sequence of 1,746 bp of mtDNA from
Ambystoma tigrinum tigrinum, describe the nucleotide composition of the
intergenic spacer in all of the species of Ambystomatidae, and compare it
to other coding and noncoding regions of Ambystoma and several other
vertebrate mtDNAs. The nucleotide substitution rate of the intergenic
spacer is approximately three times faster than the substitution rate of
the control region, as shown by comparisons among six Ambystoma
macrodactylum sequences and eight members of the Ambystoma tigrinum
complex. We also found additional inserts within the intergenic spacers of
five species that varied from 87-444 bp in length. The presence of the
intergenic spacer in all sexual species of Ambystomatidae suggests that it
arose at least 20 MYA and has been a stable component of the ambystomatid
mtDNA ever since. As such, it represents one of the few examples of a large
and persistent intergenic spacer in the mtDNA of any vertebrate clade.
相似文献
63.
Influence of the Hydrological Cycle on the Bacterioplankton of an Impacted Clear Water Amazonian Lake 总被引:4,自引:0,他引:4
Abstract
Free-living and attached bacterial population sizes were determined fortnightly from December 1991 to December 1992 in natural
and disturbed areas of an Amazonian clear water lake (Batata Lake, Pará, Brazil) impacted by bauxite tailings. The bacterioplankton
showed distinct patterns during different phases of the hydrological cycle. Total bacterial population size and rates of thymidine
incorporation (measured during high and low water phases) were high during low water, with values ranging from 3.3 × 105 to 1.1 × 106 cells ml−1, and from 0.28 to 4.01 μg C l−1 h−1, respectively. The population size of free-living bacteria was larger at the natural station, while no differences were observed
between attached bacterial populations at both stations. However, production and turnover rate of attached bacteria were high
at the disturbed area. During low water, bacterial growth appeared to be driven mainly by the input of dissolved organic carbon
(DOC) from phytoplankton origin. During high water, bacterial abundance was reduced, probably as the result of dilution and
the input of less labile DOC from floodplains. The presence of bauxite tailings seems to influence bacterial dynamics in an
indirect way, probably due to shading of phytoplankton cells and, hence, reducing the DOC supply for bacterial growth. This
study, the first on the microbial ecology of an Amazonian clear water lake, demonstrated that water level variations exert
a strong influence on the bacterioplankton dynamics.
Received: 9 January 1996; Accepted 6 November 1996 相似文献
64.
C. A. Assis 《Journal of fish biology》2003,62(6):1268-1295
The general morphology of the asterisci from recent European teleosts is described, terminology for their parts is proposed, their three major morphological types are identified and the relevance of the morphology of these otoliths in species identification, and as a source of information for studies on fish phylogeny and systematics is discussed. 相似文献
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68.
Graciete S. Silva Denilson J. Assis Janice I. Druzian Maria B. P. P. Oliveira Paulo L. L. Ribeiro Soraia M. Cordeiro Cleber A. Schmidt 《Indian journal of microbiology》2017,57(3):351-358
The conditions of storage, cultivation and maintenance of microbial cultures should preserve the microbiological homogeneity, phenotypic and genotypic characteristics to ensure better reproducibility of metabolic production. To evaluate the influence of the storage condition on the composition of cell fatty acids, genetic profile and biochemical characteristics of Xanthomonas campestris pv. mangiferaeindicae IBSBF 2103, as well as, to identify its relationship with the yielding and viscosity of the xanthan gum produced, this study monitored the strain preserved in two simple and widely used conditions, ultra-freezer (?80 °C) and refrigeration (3–8 °C) during 5 months. Were identified and quantified 13 fatty acids. The cells preserved at ?80 °C showed more stable concentration of all fatty acids, producing more xanthan gum and with higher viscosity. The chromosomal analysis obtained with the enzyme XbaI revealed 17 distinct fragments with maximum size of 485 kilobases, without variations among the subcultures maintained in both storage conditions. The X. campestris pv. mangiferaeindicae subcultures preserved at ?80 °C showed less pronounced phenotypic variations, which had positive influence in the qualitative and quantitative characteristics of the xanthan gum produced. 相似文献
69.
70.
Daniel Alvares Silveira de Assis Vinícius Augusto Dias-Filho André Lincoln Barroso Magalhães Marcelo Fulgêncio Guedes Brito 《Studies on Neotropical Fauna and Environment》2017,52(3):228-238
Alterations in the hydrologic regime downstream from hydroelectric dams create a high invasibility to non-native species. This study aims to analyze the establishment of non-native Metynnis lippincottianus downstream of the Xingó Dam, lower São Francisco River, Brazil. Adults in reproduction were found throughout the study. Gonadosomatic index was higher in the reproductive phases and the species produces a large number of small oocytes. Hydrometric level and water flow data after the construction of Xingó Dam showed decrease in both parameters, facilitating the establishment of M. lippincottianus. Management actions are suggested to reduce the threat on the native biota. 相似文献