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991.
转录因子是指那些专一性地结合于DNA特定序列上、能激活或抑制其他基因转录的蛋白质(王少峡等,2004)。DREB(dehydration responsive element binding protein)转录因子是一种特异性的转录因子,当植物在干旱、低温及盐等逆境胁迫下,DREB转录  相似文献   
992.
[目的]探究新疆某奶牛场奶牛流产病因.[方法]采集的19份血清样品和4份牛流产胎儿脑组织进行布氏杆菌病凝集实验、弓形虫PCR检测和新孢子虫病ELISA方法检测,参考GenBank登录的犬新孢子虫种Nc-5序列[1],设计引物,建立新孢子虫病的PCR检测方法.[结果]调查结果显示该牛场布氏杆菌病与弓形虫病感染均呈阴性,新孢子虫病感染率为14.3;(2/19).新孢子虫PCR诊断方法的最佳退火温度为57℃,灵敏度为35 pg/μL.用建立后的PCR方法检测流产胎儿,感染率为50.0;(2/4).[结论]新孢子虫病是导致该厂奶牛流产的重要原因之一,为今后新疆地区有效预防和治疗新孢子虫病提供了一定的科学依据.  相似文献   
993.
A Tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) system was employed to investigate the role of the tomato ethylene receptor ETR4. By comparing wilting symptoms of verticillium wilt in wild-type, ethylene-insensitive Never ripe ( Nr ) mutant tomato plants and ETR4 -silenced plants, it was demonstrated that disease severity in the Nr and ETR4 -silenced plants was statistically reduced compared to wild-type plants. Disease incidence and severity were reduced by 11 and 20%, respectively, in the Nr plants compared to the wild-type plants, at 33 days post-inoculation (d.p.i.). In the ETR4 -silenced plants, disease incidence and severity were reduced by 14 and 15%, respectively, compared to the TRV -only-inoculated plants, at 37 d.p.i. Quantification of Verticillium dahliae by qPCR revealed that the reduction in symptom severity in the Nr plants was associated with significant reduction of growth of the pathogen in the vascular tissues of the Nr plants compared to that in the wild-type plants, suggesting that impaired perception of ethylene via the Never-ripe receptor results in increased disease resistance. Fungal reduction was evident at each sampling day in the Nr plants, ranging from 1·5 to 1·75 times less than that in the wild-type plants. Fungal quantification in the ETR4- silenced and TRV -only-inoculated plants showed similar levels of fungal biomass.  相似文献   
994.
In organic seed production of Brassica vegetables, infections by Alternaria brassicicola and A. brassicae can cause severe losses of yield and seed quality. Four field experiments with or without artificial inoculation with A. brassicicola were conducted in organically managed seed‐production crops of cauliflower cv. Opaal RZ in 2005 and 2006 in the Netherlands. The development of A. brassicicola and A. brassicae on pod tissues and developing seeds was followed and seed quality was assessed. Alternaria brassicicola was externally present on 1·2% of the seeds 14 days after flowering and observed internally within 4 weeks after flowering. In both seasons, seed colonization by the pathogen increased slowly until maturation but sharply increased during maturation. A similar pattern was found for the colonization of pod tissues by A. brassicicola as quantified by TaqMan‐PCR. The incidence of A. brassicicola on mature seeds reached 70–90%. Internal colonization was found for 62–80% of the seeds. External and internal seed colonization by A. brassicae was much lower, with incidences below 3%. The quality of harvested seeds was generally low, with less than 80% of seeds able to germinate. Seed quality was not affected by warm water treatments. It was concluded that A. brassicicola and A. brassicae have the potential to infect pods and seeds soon after flowering. For the production of high quality seeds, producers must prevent such early infections. Therefore, new control measures are needed for use in organic cropping systems.  相似文献   
995.
This study analysed genomic variation of the translation elongation factor 1α (TEF‐1α) and the intergenic spacer region (IGS) of the nuclear ribosomal operon of Fusarium oxysporum f. sp. cubense (Foc) isolates, from different banana production areas, representing strains within the known races, comprising 20 vegetative compatibility groups (VCG). Based on two single nucleotide polymorphisms present in the IGS region, a PCR‐based diagnostic tool was developed to specifically detect isolates from VCG 01213, also called tropical race 4 (TR4), which is currently a major concern in global banana production. Validation involved TR4 isolates, as well as Foc isolates from 19 other VCGs, other fungal plant pathogens and DNA samples from infected tissues of the Cavendish banana cultivar Grand Naine (AAA). Subsequently, a multiplex PCR was developed for fungal or plant samples that also discriminated Musa acuminata and M. balbisiana genotypes. It was concluded that this diagnostic procedure is currently the best option for the rapid and reliable detection and monitoring of TR4 to support eradication and quarantine strategies.  相似文献   
996.
Controlled‐environment and field experiments were done to quantify the individual contribution of seed‐tuber and soilborne inoculum of Colletotrichum coccodes in causing black dot disease of potato tubers. Seed‐tuber and soilborne inocula of C. coccodes were quantified using an existing real‐time PCR assay and related to subsequent incidence and severity of disease. In four field trials, a controlled‐environment experiment and through the monitoring of 122 commercial crops, seed‐tuber inoculum was found to be relatively less important than soilborne inoculum in causing black dot, and the level of seed‐tuber inoculum did not significantly affect either the incidence or severity of disease or the percentage of progeny tubers deemed unmarketable. By contrast, soilborne inoculum had the potential to result in high levels of disease and the level of C. coccodes soil infestation (pg DNA g?1 soil) was found to have a significant effect. At soil infestation levels below 100 pg DNA C. coccodes g?1 soil, 7% of commercial crops had an incidence of black dot greater than 20%, increasing to 40% and 57% of crops at levels of 100–1000 pg g?1 and >1000 pg g?1 soil, respectively. These arbitrary threshold levels for soilborne inoculum related to disease risk are discussed. Interpretation of disease risk based on inoculum levels must, in the future, be informed by agronomic variables and potential control strategies.  相似文献   
997.
 The investigation showed that stem-pitting Citrus tristeza virus (CTV)occurred commonly in citrus production areas in several varieties of Hunan Province. Accurate detection of CTV strains was performed by p23/PCR method, PCR and the results indicated that the most samples were infected with several CTV isolates. Three mild strains were isolated and their pathogenicity was identified by biological identification, it indicated that p23/PCR groups had uniformity with the pathogenicity of CTV isolates. Furthermore, three mild isolates were tested in the cross protection by analysis of biological symptoms and composition of p23 gene. Different protecting effects were observed among these strains and W17 mild isolate was effective.  相似文献   
998.
采用realtime quantitative PCR方法测定了Ba33胞外蛋白对烟草花叶病毒RNA在叶片内积累的抑制作用,结果显示:与接种TMV+PBS对照相比,Ba33蛋白与TMV混合接种、接种TMV前24h喷雾Ba33蛋白及接种TMV后6h喷雾Ba33蛋白,均能显著抑制叶片内RNA积累,其中以接种前24h喷雾Ba33蛋白抑制效果最好。  相似文献   
999.
蔬菜保护地木霉菌rDNA-ITS序列和UP-PCR遗传多样性分析   总被引:2,自引:0,他引:2  
采用传统形态学分类和ITS序列比对的方法,研究蔬菜保护地土壤中木霉菌种群分布和遗传多样性。木霉菌分离培养结果显示,共获得397株木霉菌,鉴定出11个种,分别为:长枝木霉Trichoderma longibrachiatum、深绿木霉T.atroviride、哈茨木霉T.harzianum、粘绿木霉T.viren、微孢木霉T.minutisporum、拟康木霉T.pseudokoningii、黄绿木霉T.aureoviride、非钩木霉T.inhamatum、棘孢木霉T.asperellum、长孢木霉T.longipile和螺旋木霉T.helicum。经ITS序列建立系统发育树后,将木霉菌分为5个组。用5条通用引物经UP-PCR扩增后,扩增出46条谱带,其中多态性条带43条,占总条带数的93.5%。遗传多样性分析表明,当相似系数为0.80时,可将24个菌株划分为9个组。UP-PCR与ITS序列相比,更能体现木霉菌种间和种内的亲缘关系及遗传差异性,可以作为木霉菌分类的辅助方法。  相似文献   
1000.
臀纹粉蚧属有多个种类是重要的农业害虫,大洋臀纹粉蚧(Planococcus minor(Maskell))和南洋臀纹粉蚧(Planococcus lilacius Cockerell)是我国有重要检疫意义的有害生物.这两种臀纹粉蚧经常从进口泰国和东南亚水果口岸检疫中截获,但形态学方法很难进行准确鉴定.本研究首次利用mtDNA COI基因设计了两条特异性探针,应用TaqMan实时荧光PCR方法对大洋臀纹粉蚧和南洋臀纹粉蚧进行了快速准确鉴定.  相似文献   
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