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951.
The braconid parasitoid Microplitis mediator (Haliday) is a key natural enemy of the cabbage moth, Mamestra brassicae (L.), in Europe. In the context of an Integrated Pest Management approach, the use of selective insecticides is essential
for the conservation of naturally occurring beneficial arthropods. The present laboratory study investigated the side effects
of six insecticides applied at recommended field rates on adults and cocooned pupae of M. mediator. Male and female parasitoids were paired in drum cells contaminated with dry residues of insecticides. Besides lethal effects
after 24 h, parasitization capacity and longevity of the surviving parasitoids was evaluated. Lethal effects on cocooned pupae
were also investigated by assessing adult emergence from treated cocoons. Pirimicarb caused 100% adult mortality after 24 h,
whereas the other tested insecticides caused no direct toxic effects. However, sub-lethal effects in terms of reduced parasitization
activity, percentage of parasitism or female longevity were found for flonicamid, pymetrozine, spinosad and thiacloprid. Spirotetramat
shortened only male longevity. Adult emergence from treated cocoons was reduced only by flonicamid and pymetrozine. 相似文献
952.
Black nightshade (Solanum nigrum L.) is a troublesome weed worldwide, affecting a large number of crops. As weed development is affected by a variety of factors,
advanced knowledge on the plant’s biological and ecological qualities can support favorable management strategies. Seed density
is an ecological factor affecting emergence and early growth of many weed species. For that reason, the current study characterizes
and quantifies the seed density impact on black nightshade seedling-emergence and early growth, and the interaction between
seed density and burial depth on these growth parameters. Greenhouse studies conducted in 2005, 2006 and 2010 examined black
nightshade seed densities of 1, 5, 10, 25 and 50 seeds per pot, buried at, 1, 2, 3, 4 and 5 cm. Impact of seed density on
weed emergence and growth was characterized by number of emerged plants and leaves, followed by biomass measurements. Seed
density had no impact on emergence at the tested burial depths. There was a strong logistic relationship (P < 0.001, and R
2
> 0.97) between time and emergence, and a strong linear relationship (P < 0.002 and R
2
> 0.86) between time and number of leaves produced in all depths and seed densities. A negative relationship was observed
between seed density and plant development and growth rate. Results of this study extend the knowledge on black nightshade
biology and support decision-making concerning rational weed management. 相似文献
953.
Mónica Berbegal Luis Armando Álvarez Ana Pérez-Sierra Josep Armengol 《Phytoparasitica》2012,40(1):1-4
Pythium isolates were recovered from endive plants (Cichorium endivia) showing vascular necrosis collected from commercial fields located in Castellón province (eastern Spain). They were identified
as Pythium tracheiphilum on the basis of their phenotypical and molecular profile. Pathogenicity tests conducted with two P. tracheiphilum isolates, obtained from endive and lettuce (Lactuca sativa), respectively, in this region, confirmed that both isolates were pathogenic to endive, with no significant differences in
virulence between them. This is the first report of vascular necrosis caused by P. tracheiphilum on endive in Spain. 相似文献
954.
M. I. Tajul Takayuki Motoyama Akikazu Hatanaka M. Sariah Hiroyuki Osada 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):91-100
Four green-odour compounds—trans-2-hexenal, cis-3-hexenol, n-hexanal, and cis-3-hexenal—were applied (0.85 μg ml−1 as vapour) to rice plants in laboratory conditions to observe their biological activity against the phytopathogenic fungus
Maganporthe oryzae, which causes rice blast disease worldwide. Two compounds, trans-2-hexenal and cis-3-hexenal, showed remarkable disease suppression efficacy (99.7% and 100% suppression, respectively), while n-hexanal had moderate (86.5%) and cis-3-hexenol had weak (20.8%) disease-suppressing effects. Pre-application and post-application of trans-2-hexenal or cis-3-hexenal had slight effects on blast incidence, suggesting that these compounds had direct effects to suppress M. oryzae infection. In fact, trans-2-hexenal and cis-3-hexenal exhibited a growth suppression effect on M. oryzae. Interestingly, these two compounds inhibited appressorium formation at lower concentrations than the growth suppression.
Studies on the hypersensitive response (HR)-like reaction and plant β-1,3-glucanase activity in rice plant confirmed that
induced resistance was not the major factor involved in the disease suppression mechanism. Results of this study conclusively
showed that trans-2-hexenal and cis-3-hexenal possess potent inhibitory activities against the growth and the appressorium formation of M. oryzae and could be used as antifungal agents to significantly reduce M. oryzae infections in rice. 相似文献
955.
Michel Almaguer Teresa Irene Rojas Francisco Javier Rodríguez-Rajo María Jesús Aira 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(2):473-482
This study characterised the airborne mycobiota of a rice plantation in Bauta (Havana, Cuba), with a view to improving crop
quality. Culturable airborne fungi were sampled between March 2007 and February 2008 using a volumetric method (SAS Super
100) with potato dextrose agar as culture medium. The total fungal count was 51,425 cfu/m3. The 39 filamentous genera identified included several major rice pathogens (Bipolaris, Curvularia, Alternaria, Pyricularia, Cercospora and Fusarium) as well as potentially mycotoxigenic species of Fusarium, Penicillium and Aspergillus. Analysis of the influence of weather-related factors on spore counts revealed that total counts and Penicillium counts correlated positively with daily relative humidity, mean temperature and dew point. 相似文献
956.
Nalini Mallikarjuna Deepak R. Jadhav Kanaka Reddy Fatema Husain Kumkum Das 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):17-21
Cultivated groundnut is susceptible to late leaf spot (LLS) caused by Phaeoisariopsis personata [(Berk. & M.A. Curtis) Aex] and resistance is low to moderate in the primary gene pool of groundnut. Closely related wild
species in the secondary gene pool are highly resistant to the disease. All the closely related Arachis species are diploid and cultivated groundnut is a tetraploid. Utilization of diploid Arachis species to transfer LLS resistance is time consuming and cumbersome. New sources of Arachis hypogaea (also called synthetic groundnut) were developed at ICRISAT. These are tetraploids and the present investigation has shown
that they are resistant to LLS. 相似文献
957.
Sameh Boukef Bruce A. McDonald Amor Yahyaoui Salah Rezgui Patrick C. Brunner 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):111-122
The occurrence of fungicide resistance in Mycosphaerella graminicola populations from Tunisia was investigated by examining mutations known to be associated with strobilurin and azole resistance.
Few mutations associated with fungicide resistance were detected. No evidence for strobilurin resistance was found among 357
Tunisian isolates and only two among 80 sequenced isolates carried mutations associated with azole resistance. A network analysis
suggested that these mutations emerged independently from mutations found in previously described European populations. The
population genetic structure of M. graminicola in Tunisia was analyzed using variation at 11 microsatellite loci. Populations in Tunisia were characterized by high gene
and genotype diversity. All populations were in gametic equilibrium and mating type proportions did not deviate from the 1:1
ratio expected under random mating, consistent with regular cycles of sexual reproduction. In combination with a high degree
of gene flow among sampling sites, M. graminicola must be considered a pathogens with high evolutionary potential. Thus, control strategies against Septoria blotch in Tunisia
should be optimized to reduce the emergence and spread of resistant isolates. 相似文献
958.
Hyun Cheol Soh Ae Ran Park Sangkyu Park Kyoungwhan Back Jae Bok Yoon Hyo Guen Park Young Soon Kim 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):37-48
To elucidate the functional roles of PR10 genes from two pepper species during plant-pathogen interactions, PR10 genes were isolated from fungal-resistant (Capsicum baccatum var. PBC80) and fungal-susceptible (C. annuum var. Yeoju) pepper fruits infected with anthracnose fungus (Colletotrichum acutatum). Despite strong nucleotide sequence identity, there were significant differences in the patterns of gene expression and
protein accumulation between the genes from the two host species. Induced expression of the PR10 mRNA in PBC80 (bacPR10) was highly maintained from 24 h after infection (HAI) rather than that in Yeoju (annPR10). These mRNA expression patterns were correlated with the level of respective protein that was detected as two or three
bands in each species. Substantial induction of bacPR10 proteins was confirmed by 2D-gel analysis followed by immunoblotting. Immunolocalization study showed that deposition
of bacPR10 was exclusively observed in the pericarp of PBC80 fruits after fungal infection, suggesting functional significance
in defence. Additionally, in vitro analysis of the enzymatic properties of PR10 proteins revealed that recombinant bacPR10 had higher ribonucleolytic activity
and exhibited less sensitivity to proteinase treatment than did annPR10. Taken together, these results support the idea that
relative abundance and prolonged longevity of bacPR10 in PBC80 fruits may contribute to their increased resistance in response
to the anthracnose fungus, as compared with Yeoju fruit. 相似文献
959.
Zhixiang Zhang Shan Peng Dongmei Jiang Song Pan Hongqing Wang Shifang Li 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):9-16
This study aimed to develop a polyprobe for the simultaneous detection of four viroids that infect grapevine: Hop stunt viroid (HSVd), Australian grapevine viroid (AGVd), Grapevine yellow speckle viroid-1 and 2 (GYSVd-1, 2), using a non-isotopic dot blot hybridization technique. A polyprobe was constructed by cloning tandem
full-length sequences of HSVd, AGVd and GYSVd-1 into a single vector. The cRNA polyprobe detected all four viroids with similar
sensitivity to that obtained using individual probes. In addition, samples of 78 varieties from Beijing and Xinjiang were
analyzed using the polyprobe to survey the incidence of grapevine viroids in China. The result demonstrated that grapevine
viroids were detected in 56 (71.8%) varieties. In this study, a rapid, reliable and cost-effective approach to the simultaneous
detection of four grapevine viroids has been developed which has the potential for routine use in quarantine and certification
programs. 相似文献
960.
Biological control of postharvest diseases of fruit 总被引:1,自引:0,他引:1
Carla Alexandra Nunes 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(1):181-196
Postharvest decay in harvested fruit causes considerable economical losses. Fungicides are the primary means to control these
losses. Public concern in food safety and environmental issues and the increase of pathogen resistant populations have enhanced
the interest in developing alternative methods to fungicides to control postharvest fruit decay. During the last two decades
a huge information and advances concerning the selection of antagonists, mode of action, different approaches to enhance biocontrol
activity, formulation and production have been achieved, and some biofungicides are already in the market. It is likely that
several more products will enter the market in the near future, as the result of the biological control research programs
worldwide. Nonetheless, it is necessary to continue finding new potential microorganisms, better understanding the mode of
action, and pathogen, antagonist and host interactions, to increase the potential of biocontrol helping to become a real alternative
to synthetic postharvest fungicides. This article presents an overview of postharvest biological control approaches and explores
new research possibilities to improve biocontrol activity. 相似文献