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141.
Biological Control of Sclerotinia Diseases of Rapeseed by Aerial Applications of the Mycoparasite Coniothyrium minitans 总被引:1,自引:0,他引:1
G. Q. Li H. C. Huang H. J. Miao R. S. Erickson D. H. Jiang Y. N. Xiao 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(4):345-355
Indoor and field experiments were conducted to evaluate the efficacy of applying the mycoparasite Coniothyrium minitans to the aerial parts of rapeseed plants at the flowering stage to control sclerotinia diseases caused by Sclerotinia sclerotiorum. Under controlled conditions, a petal inoculation technique was used to determine the effect of conidial suspensions of C. minitans on suppression of sclerotinia leaf blight. Results showed that C. minitans was effective in inhibiting infection initiated by ascospores of S. sclerotiorum on flower petals by restricting mycelial growth of the pathogen. Suppression of lesion development was related to the conidial
concentration of C. minitans, with larger lesions at low concentration (5×103conidia ml−1), but smaller lesions at high concentration (5×104 conidia ml−1 or higher). When C. minitans-treated rapeseed leaves were inoculated with mycelia of S. sclerotiorum, C. minitans failed to prevent infection of leaves, but caused a significant reduction in number of sclerotia produced on the diseased
leaves. No significant difference in efficacy was detected between the two isolates of C. minitans, LRC 2137 and Chy-1, on the two rapeseed cultivars, Westar (spring type) and Zhongyou 821 (winter type). Results of field
trials showed a significant reduction of stem rot of rapeseed in four (1997, 1999, 2003 and 2004) out of five years by aerial
application of C. minitans, compared with controls. No significant difference in suppressive efficacy was observed between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + benomyl (50 μg ml−1) and benomyl (100 μg ml−1) in 2003, and between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + vinclozolin (100 μg ml−1) and vinclozolin (500 μg ml−1) in 2004. Sclerotia of S. sclerotiorum collected from diseased plants in plots treated with C. minitans in 1999, 2000 and 2003, or with C. minitans + benomyl in 2003 were infected by C. minitans at frequencies ranging from 21.3 to 54.5%. This study concludes that aerial spraying of C. minitans is an effective method for controlling sclerotinia diseases of rapeseed. 相似文献
142.
半番鸭羽色性状AFLP标记初步研究 总被引:1,自引:0,他引:1
本研究初步利用AFLP标记对半番鸭及其母本-北京鸭进行检测。结果显示,AFLP标记扩增带丰富,10对引物组合共检测到2046条扩增带,平均每对引物组合/每个池DNA可产生60.15条。半番鸭白羽性状特有的扩增带共有15条,分布在E AAC/M CTA、E AAC/M CTT、E AAG/M CAG、E ACA/M CTC、E ACT/M CTA和E ACT/M CTC等6对引物组合上,为半番鸭个体羽色与AFLP标记相关分析和验证提供了素材。 相似文献
143.
An introductory study was conducted to investigate the pyrethroid resistance ofHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) strains in Turkey, collected from cotton fields in the Adana and Antalya provinces, through
two different synthetic pyrethroid insecticides: lambda-cyhalothrin and esfenvalerate. In addition, the roles of glutathioneS-transferases (GSTs) in this resistance mechanism were analyzed. It was found that whereas resistance ratios for lambda-cyhalothrin
(LD50 levels) were 3- and 98-fold increased in the Adana and Antalya strains, respectively, esfenvalerate ratios were 3.3- and
92.3-fold increased in the Adana and Antalya strains, respectively, with respect to the susceptible strain. Furthermore, Adana
and Antalya strains showed 2.4- and 2.9-fold higher GST activities than the susceptible strain, respectively. In the Antalya
field strain, the minor increase in GST activity compared with the resistance levels implies that GSTs may be not greatly
involved in this resistance. It also provides evidence that they could not be the only metabolic mechanism responsible for
resistance to lambda-cyhalothrin and esfenvalerate inH. armigera from Turkey.
http://www.phytoparasitica.org posting Nov. 16, 2006. 相似文献
144.
145.
M. Lodovica Gullino Riccardo Savigliano Giuliana Gasparrini Corrado Clini 《Phytoparasitica》2007,35(4):321-329
Methyl bromide (MB) was phased out on January 1, 2005, and a Critical Use Exemption (CUE) process has been established in
order to define the rules for allocating the needed amounts of the fumigant. This paper deals with the effects of the CUE
process on Italian horticulture. The actual usage of the amounts of MB allocated to Italy for the year 2005 in the different
areas and on the economically most important crops was monitored and critically evaluated. The usage pattern monitored shows
that already in the first year after MB phaseout, Italy was able to replace it completely on crops such as zucchini, salad
greens, basil and watermelon. However, on crops such as tomato, pepper, melon, eggplant, strawberry, and cut flowers, further
work is required in order fully to replace MB. The emerging problems and research needs are discussed briefly. 相似文献
146.
David White Weidong Chen 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):3-12
Ascochyta blight is a serious disease of cool-season grain legumes (chickpea, faba bean, lentil and pea) caused by fungal
species of the anamorphic genus Ascochyta and related genera. Despite extensive studies on the biology, ecology, epidemiology
and management of the disease, little is known about the pathogenic determinants of these pathogens. This research aims at
using Ascochyta rabiei as a model for the genus in investigating genetic factors of pathogenicity, with the ultimate goal of elucidating pathogenic
mechanisms. Three advances were made: (1) insertional mutants with altered pathogenicity were identified through in vivo screening,
and genomic regions adjacent to the insertion sites in selected mutants were determined; (2) a phage library of A. rabiei genomic DNA was constructed, and the library was estimated to provide complete coverage of the A. rabiei genome. This library was used successfully to recover clones with DNA adjacent to insertional mutation sites and to isolate
specific genes; (3) DNA probes specific for an acyl-CoA ligase (cps1) and a polyketide synthase gene (pks1) were developed and library clones containing the corresponding genomic regions were identified from the phage library.
These advances provide the foundation and necessary tools for experimentation of ectopic complementation assays and targeted
mutagenesis to elucidate the genetic mechanisms of pathogenicity of A. rabiei. 相似文献
147.
148.
Simulating the cumulative effects of multiple forest management strategies on landscape measures of forest sustainability 总被引:1,自引:2,他引:1
While the cumulative effects of the actions of multiple owners have long been recognized as critically relevant to efforts
to maintain sustainable forests at the landscape scale, few studies have addressed these effects. We used the HARVEST timber
harvest simulator to predict the cumulative effects of four owner groups (two paper companies, a state forest and non-industrial
private owners) with different management objectives on landscape pattern in an upper Michigan landscape managed primarily
for timber production. We quantified trends in landscape pattern metrics that were linked to Montreal Process indicators of
forest sustainability, and used a simple wildlife habitat model to project habitat trends. Our results showed that most trends
were considered favorable for forest sustainability, but that some were not. The proportion of all age classes and some forest
types moved closer to presettlement conditions. The trend for the size of uneven-aged patches was essentially flat while the
average size of patches of the oldest and youngest age classes increased and the size of patches of the remaining age classes
decreased. Forest fragmentation generally declined, but edge density of age classes increased. Late seral forest habitat increased
while early successional habitat declined. The owners use different management systems that cumulatively produce a diversity
of habitats. Our approach provides a tool to evaluate such cumulative effects on other landscapes owned by multiple owners.
The approach holds promise for helping landowner groups develop and evaluate cooperative strategies to improve landscape patterns
for forest sustainability. 相似文献
149.
Identification of functional corridors with movement characteristics of brown bears on the Kenai Peninsula,Alaska 总被引:2,自引:1,他引:2
Tabitha A. Graves Sean Farley Michael I. Goldstein Christopher Servheen 《Landscape Ecology》2007,22(5):765-772
We identified primary habitat and functional corridors across a landscape using Global Positioning System (GPS) collar locations
of brown bears (Ursus arctos). After deriving density, speed, and angular deviation of movement, we classified landscape function for a group of animals
with a cluster analysis. We described areas with high amounts of sinuous movement as primary habitat patches and areas with
high amounts of very directional, fast movement as highly functional bear corridors. The time between bear locations and scale
of analysis influenced the number and size of corridors identified. Bear locations should be collected at intervals ≤6 h to
correctly identify travel corridors. Our corridor identification technique will help managers move beyond the theoretical
discussion of corridors and linkage zones to active management of landscape features that will preserve connectivity. 相似文献
150.
Prediction of multinomial probability of land use change using a bisection decomposition and logistic regression 总被引:1,自引:1,他引:1
Land use change is an important research area in landscape ecology and urban development. Prediction of land use change (urban
development) provides critical information for making the right policies and management plans in order to maintain and improve
ecosystem and city functions. Logistic regression is a widely used method to predict binomial probabilities of land use change
when just two responses (change and no-change) are considered. However, in practice, more than two types of change are encountered
and multinomial probabilities are therefore needed. The existing methods for predicting multinomial probabilities have limits
in building multinomial probability models and are often based on improper assumptions. This is due to the lack of proper
methodology and inadequate software. In this study, a procedure has been developed for building models to predict the multinomial
probabilities of land use change and urban development. The foundation of this procedure consists of a special bisection decomposition
system for the decomposition of multiple-class systems to bi-class systems, conditional probability inference, and logistic
regression for binomial probability models. A case study of urban development has been conducted to evaluate this procedure.
The evaluation results demonstrated that different samples and bisection decomposition systems led to very similar quality
and performance in the developed multinomial probability models, which indicates the high stability of the proposed procedure
for this case study. 相似文献