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21.
A. Sisto M. G. Cipriani S. Tegli M. Cerboneschi G. Stea E. Santilli 《Plant pathology》2007,56(3):366-372
The genetic diversity of 71 Pseudomonas savastanoi pv. savastanoi strains isolated from different host species and from diverse geographical regions was determined by fluorescent amplified fragment length polymorphism (f-AFLP) analysis. The study was carried out using three different selective primer combinations. Strains of P. syringae pv. syringae , P. syringae pv. phaseolicola , P. syringae pv. glycinea , P. syringae pv. tagetis and P. amygdali were also included as outgroups. Based on cluster analysis of f-AFLP data, all P. savastanoi pv. savastanoi strains showed a high degree of similarity, grouping in a cluster and forming a taxon clearly separate from outgroup strains. AFLP analyses failed to support placing strains of P. savastanoi pv. savastanoi , P. syringae pv. phaseolicola and P. syringae pv. glycinea in the same species. Strains of P. savastanoi pv. savastanoi formed subclusters that correlated with the host species. Strains identified within these subclusters were related to the geographical region where the strains were isolated. Strains of P. savastanoi pv. savastanoi from olive were divided into two subclusters. Strains from oleander were differentiated from those from ash and were divided into two additional subclusters, distinct from olive strains. Three strains isolated from jasmine showed a high level of similarity among them but, at a lower Dice similarity coefficient, were linked to a subcluster including olive strains. Finally, two strains isolated from privet were similar to strains from olive and were included in the same subcluster. 相似文献
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Pythium yorkensis sp. nov., a potential soybean pathogen from southeastern Pennsylvania,USA 下载免费PDF全文
Biodiversity surveys of natural as well as agricultural ecosystems commonly reveal novel isolates. A new species, Pythium yorkensis sp. nov., is reported here, isolated from field soil during a survey of oomycete diversity in symptomless soybean across southeastern Pennsylvania. Molecular data from both mitochondrial and nuclear loci support a unique phylogenetic position for the isolates collected, and morphological features distinguish this new species from close relatives in Pythium clade J. Pathogenicity assays suggest that this new species may be a potential agricultural pathogen, as isolates were mildly aggressive on soybean. This study highlights the continued need for culture‐based surveys in collaboration with high‐throughput sequence‐based approaches for environmental sampling. 相似文献
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利用RT-PCR和RACE技术克隆了小菜蛾(Plutella xylostella)鱼尼丁受体(Px-RyR)基因,其核苷酸序列全长15 748bp,5′非编码区267bp,3′端非编码区109bp,开放阅读区全长为15 372bp(GenBank登录号:JF927788),编码5 123个氨基酸残基。估测其蛋白分子量为579.39ku,等电点为5.45。该基因编码氨基酸序列和其他鳞翅目昆虫RyR氨基酸序列比对相似性较高(92%),与哺乳动物3种亚型RyRs的相似性为45%~47%。此外,二级结构预测,其C-末端存在6个跨膜区域;且Px-RyR中存在一个出现4次重复,长度为89~95个氨基酸的RyR结构域,平均相似性为33%。 相似文献
24.
Li-Wang Liu Yan Wang Yi-Qin Gong Tong-Min Zhao Guang Liu Xiao-Yan Li Fan-Min Yu 《Scientia Horticulturae》2007
Three DNA molecular marker systems, RAPD, ISSR and SSR, were used to test seed genetic purity of two commercial hybrid tomato (Lycopersicon esculentum L.) cultivars ‘Hezuo 903’ and ‘Sufen No. 8’. Genomic DNA from the two F1 hybrid cultivars and their corresponding parental lines was screened with 218 RAPD decamer primers, 54 ISSR primers and 49 SSR primers. Among the 321 primers, 4 primers for ‘Hezuo 903’ and 3 for ‘Sufen No. 8’, which could produce both female and male parent-specific markers, were selected for testing the genetic purity. A total of 210 hybrid individuals of each cultivar were analyzed using the identified primers. The combined results of the marker analysis showed that eight of the 210 F1 plants in ‘Hezuo 903’ and 13 of 210 in ‘Sufen No. 8’ were false hybrids, and the overall genetic purity of the two F1 hybrid seed lots was 96.2 and 93.8%, respectively. This study showed that RAPD and SSR markers could provide a practical and efficient tool in quality control of the tomato commercial hybrid seeds. 相似文献
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Rust resistance in the sunflower line P386 is controlled by Pu6, a gene which was reported to segregate independently from other rust resistant genes, such as R4. The objectives of this work were to map Pu6, to provide and validate molecular tools for its identification, and to determine the linkage relationship of Pu6 and R4. Genetic mapping of Pu6 with six markers covered 24.8 cM of genetic distance on the lower end of linkage Group 13 of the sunflower consensus map. The marker most closely linked to Pu6 was ORS316 at 2.5 cM in the distal position. ORS316 presented five alleles when was assayed with a representative set of resistant and susceptible lines. Allelism test between Pu6 and R4 indicated that both genes are linked at a genetic distance of 6.25 cM. This is the first confirmation based on an allelism test that at least two members of the Radv/R4/R11/ R13a/R13b/Pu6 cluster of genes are at different loci. A fine elucidation of the architecture of this complex locus will allow designing and constructing completely new genomic regions combining genes from different resistant sources and the elimination of the linkage drag around each resistant gene. 相似文献
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小麦条锈病和白粉病成株抗性研究进展与展望 总被引:9,自引:4,他引:9
利用成株抗性是小麦抗病育种的重要方向,本文综述了小麦条锈病和白粉病成株抗性鉴定方法、基因定位和克隆及其在育种中的应用。将报道的72个条锈病成株抗性数量性状遗传位点(quantitative trait loci,QTL)和82个白粉病成株抗性QTL整合到一张连锁图谱上,控制2种病害的基因簇(≥5个QTL)有8个,其中位于7DS的Yr18/Lr34/Pm38和1BS的Yr29/Lr46/Pm39对条锈病、叶锈病和白粉病均表现成株抗性,位于4DL的Yr46/Lr67位点可能也对白粉病表现成株抗性,Yr18/Lr34/Pm38和Yr36已被克隆,Yr29/Lr46/Pm39的克隆已取得良好进展,为培育兼抗和成株抗性相结合的品种提供了可用基因。总结了成株抗性在中国小麦育种中的应用现状,并用实例证实了培育成株抗性品种的可行性,建议对兼抗条锈病和白粉病成株抗性的咸农4号和小偃6号等进行遗传分析,育种工作者和品种审定部门需要转变观念,将成株抗性利用作为国内条锈病和白粉病抗性育种的重要内容。 相似文献