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881.
Ringø E Seppola M Berg A Olsen RE Schillinger U Holzapfel W 《Systematic and applied microbiology》2002,25(1):120-129
An atypical strain of Carnobacterium divergens, strain 6251, was isolated from the small intestine of Arctic charr (Salvelinus alpinus L.), fed high dietary carbohydrate. This strain showed marked growth inhibitory effects in vitro against the fish pathogens Aeromonas salmonicida subsp. salmonicida (furunculosis), Vibrio anguillarum (vibriosis) and Vibrio viscocus (winter ulcer). The strain is a non-motile Gram-positive psychrotrophic rod that lacks both catalase and oxidase, grows at pH 9.1 (CTAS agar), but not on acetate containing media (pH < or = 5.4), on TCBS or at < or =6% sodium chloride content. Strain 6251 is facultatively anaerobic and utilises tryptone as a sole source of nutrient. Further characterisation showed the most abundant cellular fatty acid of strain 6251 to be oleic acid (18:1) (n-9) (36.0%). Sequencing of a 16S rDNA region of 578 nucleotides and AFLP microbial fingerprinting suggested that strain 6251 is not closely related to any carnobacteria known, however, DNA-DNA similarity determinations showed high similarity (96.2%) with the type strain of Carnobacterium divergens. The unique phenotypic attributes of this strain represent new information on the biodiversity and ecology of carnobacteria and especially of the species C. divergens. 相似文献
882.
Colonization of Lonicera periclymenum L. (honeysuckle) was studied by RAPD analysis of young ramets in two woodlots planted 20 years ago, and in all ramets in older woodlots within a range of 1 km. Mature ramets that climbed in a particular tree always belonged to one individual. Twenty-five percent of the mature individuals had reproduced vegetatively to other trees or patches nearby, which indicates that the larger part of reproduction is sexual. Some young plants that were growing at close distances from each other were genetically highly similar and shared high similarities to the same mature plants. They may be the product of one dispersal event. Detection of parents of young individuals by exclusion was not successful, because of the dominant nature of the bands. Average distances from young plants to genetically most similar mature plants were variable, due to the small number of colonization events. However, four ways of analysis of genetic similarity among all individuals indicated that exchange of genetic material by seed and pollen occurs to a large extent over small distances and within woodlots: (i) using the Mantel test, pairs of individuals with highest similarity were found significantly more often in the same woodlot than in different woodlots; (ii) genetic similarities between individuals decreased significantly with geographical distance, but only for distances up to 300 m; (iii) individuals of woodlots in the Western part of the study area were hardly related to individuals in the Eastern part of the study area, a distance of 2–3 km; (iv) ΦST in the study area was 0.186, indicating a limited gene flow between woodlots. These results are consistent with the dispersal distance as estimated from the average distance between colonized woodlots and the nearest occupied old woodlot in earlier research. 相似文献
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图聚类用于蛋白质分类问题可以获得较好结果,其前提是将蛋白质之间复杂的相互关系转化为适当的相似性网络作为图聚类分类的输入数据。本文提出一种基于BLAST检索的相似性网络构建方法,从目标蛋白质序列出发,通过若干轮次的BLAST检索逐步从数据库中提取与目标蛋白质直接或间接相关的序列,构成关联集。关联集中序列之间的相似性关系即相似性网络,可作为图聚类算法的分类依据。对Pfam数据库中依直接相似关系难以正确分类的蛋白质的计算表明,按本文方法构建的相似性网络取得了比较满意的结果。 相似文献
885.
She gets many and she chooses the best: polygynandry in Salamandrina perspicillata (Amphibia: Salamandridae)
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Valentina Rovelli Ettore Randi Francesca Davoli Daniele Macale Marco Alberto Bologna Leonardo Vignoli 《Biological journal of the Linnean Society. Linnean Society of London》2015,116(3):671-683
Polyandry is a widespread mating strategy, found in a broad number of taxa. Among amphibians, polyandry, and multiple paternity as its direct consequence, is quite common in salamanders, especially within Ambystomatidae and Plethodontidae. In the suborder Salamadroidea the existence of two different types of spermatheca allows several kinds of polyandry strategies to appear. We used multilocus microsatellite genotyping to investigate the presence of polyandry and its effects on the paternity in a previously unstudied species with a terrestrial habit, Salamandrina perspicillata. We collected gravid females in their natural habitat and analysed the paternity of the offspring by using the software COLONY and GERUD. We found that all the analysed clutches had been fertilized by 2–4 males and that in every clutch one male had sired most of the offspring. Our results confirmed that polyandry is an important component of the mating system of this species, suggesting that females are able to recognize the sperm of the male that will provide a genetic benefit for their offspring. We found evidence of female cryptic choice based on males' genetic dissimilarity: (1) males who sire most of the offspring of a given female tend to be genetically different from their sexual partner; (2) a same male, when mated with two females, sired a proportion of the offspring inversely correlated with his genetic similarity to the female; (3) genetic dissimilarity between mating partners is positively correlated with offspring heterozygosity. According to the genetic compatibility model, we hypothesized that in the observed non resource‐based mating system the indirect benefit for the offspring should reflect interactions between paternal and maternal genomes rather than the inheritance of the so‐called ‘good genes’. This study suggests a polygynandrous mating system for the study species and provides the first report in a salamandrid species in natural condition that reproductive success of males is correlated with genetic dissimilarity between mates. Moreover, we found evidence of an offspring benefit (higher heterozygosity) derived from the most genetically dissimilar father. 相似文献
886.
Paula Leitman André M. Amorim Jerônimo B. B. Sansevero Rafaela C. Forzza 《Botanical journal of the Linnean Society. Linnean Society of London》2015,179(4):587-601
To assess the main factors driving epiphytic angiosperm distribution throughout the Brazilian Atlantic Forest, we compiled 57 floristic surveys and analysed species composition under the influence of environmental variables, space and vegetation type using canonical correspondence analysis (CCA), similarity (Sorensen) and Mantel's tests. The indicator value index (IndVal) was used to find indicator species of each Brazilian Atlantic Forest vegetation type. Group sharpness analysis was performed in order to determine the appropriate group partition level. CCA showed a separation of the epiphytic flora reflecting temperature and rainfall gradients. Mantel's test showed that environment and space were highly correlated with floristic similarity. Cluster analysis, indicating floristic similarity, resolved five groups, mainly grouped by region. Clear differentiation of the Brazilian Atlantic Forest epiphytic flora on a north–south axis with a strong correlation with temperature and rainfall gradients was found. The role of space and environment on species composition varied according to distinct epiphytic species groups. In particular, for Bromeliaceae and Orchidaceae, the main factor associated with floristic similarity was space. Indicator species were found for all vegetation types apart from the Seasonal Semideciduous Forest that seemed to represent a subset of a more humid forest type. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 587–601. 相似文献
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Kai-Wei Chang Nancy A Huang I-Hsuan Liu Yi-Hui Wang Ping Wu Yen-Tzu Tseng Michael W Hughes Ting Xin Jiang Mong-Hsun Tsai Chien-Yu Chen Yen-Jen Oyang En-Chung Lin Cheng-Ming Chuong Shau-Ping Lin 《BMC genomics》2015,16(1)