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121.
122.
Philipp B. Gannibal Sonja S. Klemsdal Mark M. Levitin 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(2):175-182
Alternaria tenuissima is a common pathogen on a number of plants described in several geographic regions of the world. Genetic variation within
and between Russian Far East, North West and Caucasus populations of A. tenuissima from wheat was examined. In addition, genetic differences between isolates from various hosts were estimated. In total, 101
isolates of A. tenuissima were studied using amplified fragment length polymorphism (AFLP) with four primer combinations. Wright’s fixation index (F
st), gene flow (N
m) and gene diversity (H
s) were calculated. AFLP banding patterns indicated significant genetic distance and at the same time a low level of gene flow
between the Far East and the two other groups of isolates originating from the European part of country. The degree of similarity
between the North West and Caucasus populations was very high, as was the migration rate. Isolates analysed by UPGMA-based
cluster analysis were grouped according to location of origin but irrespective of plant host. Based on the F
st value, the group of isolates originating from wheat and barley were not found to differ significantly from each other. 相似文献
123.
Jennifer Anne Davidson Rohan B. E. Kimber 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):99-110
Ascochyta blight causes significant yield loss in pulse crops worldwide. Integrated disease management is essential to take
advantage of cultivars with partial resistance to this disease. The most effective practices, established by decades of research,
use a combination of disease-free seed, destruction or avoidance of inoculum sources, manipulation of sowing dates, seed and
foliar fungicides, and cultivars with improved resistance. An understanding of the pathosystems and the inter-relationship
between host, pathogen and the environment is essential to be able to make correct decisions for disease control without compromising
the agronomic or economic ideal. For individual pathosystems, some components of the integrated management principles may
need to be given greater consideration than others. For instance, destruction of infested residue may be incompatible with
no or minimum tillage practices, or rotation intervals may need to be extended in environments that slow the speed of residue
decomposition. For ascochyta-susceptible chickpeas the use of disease-free seed, or seed treatments, is crucial as seed-borne
infection is highly effective as primary inoculum and epidemics develop rapidly from foci in favourable conditions. Implemented
fungicide strategies differ according to cultivar resistance and the control efficacy of fungicides, and the effectiveness
of genetic resistance varies according to seasonal conditions. Studies are being undertaken to develop advanced decision support
tools to assist growers in making more informed decisions regarding fungicide and agronomic practices for disease control. 相似文献
124.
125.
Yasuhiro Tomitaka Tohru Yamashita Kazusato Ohshima 《Journal of General Plant Pathology》2007,73(3):197-208
The genetic structure of the populations of Turnip mosaic virus in Kyushu and central Honshu, Japan was assessed. The host specificity of isolates was determined, and their gene sequences
compared utilizing a population genetic approach. Phylogenetic analysis of partial sequences revealed that 32 of 49 Honshu
isolates (65%) collected during 1997–2001 belonged to the basal-BR group as did 23 of 64 isolates from Kyushu. All these basal-BR
isolates infected both Brassica and Raphanus plants. However, analyses of the positions of recombination sites in five regions of the genome (one third of the full sequence)
showed that at least four intra-lineage recombinants were present in these populations. These analyses showed that Kyushu
and Honshu shared none of these subpopulations, and genetically distinct basal-BR populations were present in the two districts.
We conclude that different basal-BR subpopulations had expanded into those districts.
The nucleotide sequences are deposited in the DDBJ/EMBL/GenBank databases under accession numbers AB267281-AB267376. 相似文献
126.
Helena P. Trenado Isabel M. Fortes Diamantina Louro Jesús Navas-Castillo 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(2):193-196
Tomato chlorosis virus causes yellow leaf disorder epidemics in many countries worldwide. Plants of Physalis ixocarpa showing abnormal interveinal yellowing and plants of Physalis peruviana showing mild yellowing collected in the vicinity of tomato crops in Portugal were found naturally infected with ToCV. Physalis ixocarpa and P. peruviana were tested for susceptibility to ToCV by inoculation with Bemisia tabaci, Q biotype. Results confirmed that ToCV is readily transmissible to both species. The infection was expressed in P. ixocarpa by conspicuous interveinal yellow areas on leaves that developed into red or brown necrotic flecks, while P. peruviana test plants remained asymptomatic. Infected plants of both P. ixocarpa and P. peruviana served as ToCV sources for tomato infection via B. tabaci transmission. This is the first report of P. ixocarpa and P. peruviana as natural hosts of ToCV. 相似文献
127.
Florian Chain Gérard Riault Maxime Trottet Emmanuel Jacquot 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(1):35-43
Serial passage experiments (SPE) of a Barley yellow dwarf virus-PAV (BYDV-PAV) isolate were performed on Zhong ZH and TC14 wheat lines to evaluate the durability of their resistance to BYDV. At different passage numbers (from the 2nd to the 114th), biological properties of the produced isolates were recorded either by monitoring infection percentages and virus titers of the first 3 weeks of viral infection or by measuring their impact on yield components. Statistical analyses using the area under pathogen progress curves and the area under concentration progress curves demonstrated that these two resistant lines induce, after only a few passages, a selection of variant(s) with significantly modified infection abilities. Isolates resulting from SPE performed on these lines induced important decreases of yield components. These results indicate that the use of Zhong ZH and TC14 lines in BYDV-resistant breeding programmes should be approached with caution. 相似文献
128.
129.
Chu-Hui Chiang Chun-Yee Lee Ching-Hsien Wang Fuh-Jyh Jan Shih-Shun Lin Tsung-Chi Chen Joseph A. J. Raja Shyi-Dong Yeh 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(4):333-348
Papaya ringspot virus (PRSV) HA 5-1, a nitrous acid-induced mild mutant of severe strain HA, widely applied for control of PRSV by cross-protection,
was used to study the genetic basis of attenuation. Using infectious clones, a series of recombinants was generated between
HA 5-1 and HA and their infectivity was analyzed on the systemic host papaya and the local lesion host Chenopodium quinoa. The recombinants that contained mutations in P1 and HC-Pro genes caused attenuated infection on papaya without conspicuous
symptoms, similar to HA 5-1. The recombination and sequence analyses strongly implicated two amino acid changes in the C-terminal
region of P1 and two in HC-Pro of HA 5-1 involved in the attenuated infection on papaya. The recombinants that infected C. quinoa plants without local lesions contained the same mutations in the C-terminal region of HC-Pro for attenuated infection on
papaya. We conclude that both P1 and HC-Pro bear important pathogenicity determinants for the infection on the systemic host
papaya and that the mutations in HC-Pro affecting pathogenicity on papaya are also responsible for the inability to induce
hypersensitive reaction on C. quinoa. 相似文献
130.
S. Stankovic J. Levic T. Petrovic A. Logrieco A. Moretti 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(2):165-172
Fusarium proliferatum can occur on a wide range of economically important vegetable plants but its role in disease is not always well established.
In 2000 and 2001, from forty-one field samples of wilting onion and garlic plants in Serbia, F. proliferatum as the predominant fungal species was isolated from root and bulbs. Seventy isolates were firstly characterized for their
sexual fertility and were shown to be mostly members of Gibberella intermedia (sixty-seven of seventy isolates, the remaining three isolates were unfertile), the sexual stage of F. proliferatum (syn. mating population D of G. fujikuroi complex). A selected set of eleven F. proliferatum isolates from both hosts were also tested for their pathogenicity and toxigenicity. Although onion and garlic plants were
susceptible to all isolates, onion plants showed a significantly higher disease severity index. Six of the eleven isolates
of F. proliferatum produced fumonisin B1 from 25 to 3000 μg g−1, and beauvericin from 400 to 550 μg g−1; ten isolates produced fusaric acid from 80 to 950 μg g−1 and moniliformin from 50 to 520 μg g−1. Finally, all isolates produced fusaproliferin up to 400 μg g−1. These results confirm F. proliferatum as an important pathogen of garlic and onion in Europe and that there is a potential mycotoxin accumulation risk in contaminated
plants of both garlic and onion. 相似文献