全文获取类型
收费全文 | 2801篇 |
免费 | 243篇 |
国内免费 | 380篇 |
专业分类
林业 | 78篇 |
农学 | 548篇 |
基础科学 | 2篇 |
167篇 | |
综合类 | 1012篇 |
农作物 | 343篇 |
水产渔业 | 192篇 |
畜牧兽医 | 631篇 |
园艺 | 125篇 |
植物保护 | 326篇 |
出版年
2024年 | 24篇 |
2023年 | 89篇 |
2022年 | 154篇 |
2021年 | 195篇 |
2020年 | 200篇 |
2019年 | 176篇 |
2018年 | 114篇 |
2017年 | 164篇 |
2016年 | 157篇 |
2015年 | 144篇 |
2014年 | 168篇 |
2013年 | 153篇 |
2012年 | 179篇 |
2011年 | 189篇 |
2010年 | 135篇 |
2009年 | 148篇 |
2008年 | 118篇 |
2007年 | 134篇 |
2006年 | 112篇 |
2005年 | 89篇 |
2004年 | 78篇 |
2003年 | 64篇 |
2002年 | 47篇 |
2001年 | 52篇 |
2000年 | 33篇 |
1999年 | 40篇 |
1998年 | 17篇 |
1997年 | 33篇 |
1996年 | 26篇 |
1995年 | 23篇 |
1994年 | 15篇 |
1993年 | 19篇 |
1992年 | 23篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 16篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1956年 | 3篇 |
1955年 | 5篇 |
排序方式: 共有3424条查询结果,搜索用时 31 毫秒
61.
62.
63.
64.
Yigal Elad 《Phytoparasitica》1991,19(3):201-209
Difluoromethylornithine (DFMO) — an inhibitor of polyamine biosynthesis, and the polyamine spermidine (Spd) reduced gray mold
of tomato, pepper, eggplant, bean andSenecio sp. leaves, and of rose petals by 37–88% when applied at 0.1–1.0 mM each. Higher doses did not result in better control.
The disease was also reduced significantly on tomato fruits by 1.0 inM DFMO and by 0.1–1.0 mM Spd, and on cucumber fruits
by 0.1–1.0 mM of both compounds, but not on grape berries. The combination of 0.2 mM DFMO with 1.0 mM Spd controlled gray
mold ofSenecio sp. and tomato leaves additively better than either treatment alone, whereas this effect was not observed in leaves of lettuce
and pepper. Ethylene production was reduced significantly by Spd applied to leaves of tomato and pepper, but not by DFMO.
Linear growth and germination of the fungus were affected by lower concentrations of DFMO (ED50 0.12–0.97 and 1.4, respectively)
as compared with Spd. Spermidine and DFMO controlled white mold(Sclerotinia sclerotiorum) as effectively as did the fungicide benomyl.
Contribution from the Agricultural Research Organization. No. 3195-E, 1991 series. 相似文献
65.
Inducible responses in plants against pathogen attack play a major role in resistance to disease. The defense responses are
mostly associated with the expression of various kinds of inducible genes. We employed differential hybridization to isolate
elicitor-inducible genes (EIGs) of tobacco (Nicotiana tabacum cv. Samsun NN) using the tobacco-fungal elicitor system. A cDNA library was constructed from tobacco leaves treated for 12
hr with hyphal wall components (HWC) prepared from Phytophthora infestans, and six EIGs were identified. Expression of all EIGs was induced after inoculation with the soybean pathogen Pseudomonas syringae pv. glycinea (nonpathogenic on tobacco) or treatment with salicylic acid, and a variety of expression patterns of EIG mRNAs was observed.
Sequence analysis of EIG cDNAs revealed similarities to genes for SAR8.2 (EIG-B39 and EIG-D14), glycine-rich protein (EIG-G7), extensin (EIG-I30), acyltransferase (EIG-I24) and unknown protein (EIG-J7). Possible roles of EIG products in disease resistance are discussed.
Received 30 August 2000/ Accepted in revised form 30 November 2000 相似文献
66.
P. Castagnone-Sereno M. Bongiovanni A. Palloix A. Dalmasso 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(6):585-590
Experiments were designed to analyze the relationships between the root-knot nematodeMeloidogyne incognita and resistant tomato and pepper genotypes. From a natural avirulent isolate, near-isogenic nematode lineages were selected with virulence either against the tomatoMi resistance gene or the pepperMe3 resistance gene. Despite the drastic selection pressure used, nematodes appeared unable to overcome the pepperMe1 gene, therefore suggesting some differences in the resistance conferred byMe1 andMe3 in this species. Nematodes virulent onMi-resistant tomatoes were not able to reproduce onMe1-resistant nor onMe3-resistant peppers, and nematodes virulent onMe3-resistant peppers were not able to reproduce onMi-resistant tomatoes nor onMe1-resistant peppers. These results clearly demonstrate the specificity ofM. incognita virulence against resistance genes from both tomato and pepper, and indirectly suggest that gene-for-gene relationships could occur between these two solanaceous crops and the nematode. 相似文献
67.
68.
综述了近年来国内外利用杀虫细菌苏云金杆菌ICP基因构建工程菌,包括植物根际定居菌、植物疫苗、重组杀蚊蓝细菌和杆状病毒Bt重组菌等研究的历程及现状、成功的范例及存在问题.文中亦讨论了该研究领域的应用前景. 相似文献
69.
Kenichi?TsuchiyaEmail author Christophe C.M.?D’Ursel Mitsuo?Horita Yuzo?Nozu 《Journal of General Plant Pathology》2003,69(5):310-315
Strains of Xanthomonas campestris pv. vesicatoria Dye 1978 (Xcv), the causal agent of bacterial spot, have been classified into two groups based on their ability to hydrolyze starch. Three monoclonal antibodies (MAbs), 7AH10, 5HB3, and 4AD2, were produced immunized against the living bacteria and were specific to and could distinguish Xcv strains able or unable to hydrolyze starch (Amy+ or Amy–). The MAb 7AH10, obtained against strain UPB141(Amy–) reacted in an enzyme-linked immunosorbent assay with all the Amy– strains (n = 19) and 1 of 11 Amy+ strains. Against Xcv 2625, an Amy– unusual phenotype strain, MAb 5HB3, recognized 97% of our worldwide collection of Xcvs (n = 30). Also against that strain, the MAb 4AD2 reacted with none of the homologous Amy– phenotypes and with 90% (n = 11) of the heterologous Amy+ phenotypes. For all the MAbs, cross reactions with other pathovars or species were less than 4% (n = 67). By assaying a Japanese collection of strains against the three MAbs, the Amy+ strains were distinguished from the Amy– strains, and their relation with other world strains could be demonstrated. All the MAbs reacted with the lipopolysaccharide fraction of the bacterial cell wall during immunoblotting. 相似文献
70.
A.N. Markoglou B.N. Ziogas 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(1):21-30
Mutants of Ustilago maydis resistant to the piperidine fungicide piperalin were isolated in a mutation frequency of 2.4 × 10–5 after UV-irradiation and selection on media containing 50gml–1 piperalin. Genetic analysis with 15 such mutant isolates resulted in the identifications of two unlinked chromosomal loci, the U/ppl-1 locus with two allelic genes (U/ppl-1A and U/ppl-1B) and the U/ppl-2 locus. The U/ppl-2 and U/ppl-1A mutations are responsible for two levels of moderate and high resistance to piperalin (resistance factor, Rf: 54 and 135, respectively, based on effective concentration causing a 50% reduction in the growth rate, EC50), while the U/ppl-1B mutation gives only a small reduction (approximately 8-fold) in piperalin sensitivity. Cross-resistance studies with other SBIs shows that the major gene (U/ppl-2 and U/ppl-1A) mutants are resistant to fenpropidin (Rf: 43 and 68), fenpropimorph (Rf: 261 and 283) and tridemorph (Rf: 9 and 10), but not to the inhibitors of C-14 demethylase (DMIs) and squalene epoxidase. The minor gene mutation U/ppl-1B codes a low-level of resistance (approximately 5—12-fold) to the above morpholine-type fungicides, but in contrast with the major gene mutations it increases 2–10 times the sensitivity to triazoles: triadimefon, triadimenol, propiconazole and flusilazole. Crosses between mutants carrying the U/ppl-genes with compatible isolates carrying the U/fpd, U/fpm or U/tdm mutations, which have been identified in previous genetic works for resistance to morpholine-type fungicides, yielded, with the exception of U/ppl-2 ×U/fpm-2 cross, a large number of recombinants with wild-type sensitivity, indicating that the mutant genes involved in these crosses, were not allelic. An additive gene effect was observed only between nonallelic minor genes U/ppl-1B and U/fpm-1B or U/tdm-1,2. Studies of the fitness of piperalin-resistant isolates showed that the reduced sensitivity of major gene mutants was not associated with changes on the phytopathogenic fitness determining characteristics, such as growth in liquid culture and pathogenicity on young corn plants. Conversely, the minor gene mutation U/ppl-1B appeared to be pleiotropic, having significantly adverse effects on the phytopathogenic fitness. 相似文献