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901.
Ueno TE Gonçalves VS Heinemann MB Dilli TL Akimoto BM de Souza SL Gennari SM Soares RM 《Tropical animal health and production》2009,41(4):547-552
Serum samples from 1028 sheep were collected from 32 herds within Federal District, in the central region of Brazil. The samples
were examined by indirect fluorescent antibody test (IFAT) using sera diluted 1:64 and 1:50 as cut-off values for the detection
of antibodies against Toxoplasma gondii and Neospora caninum, respectively. The observed prevalence for T. gondii infection was 38.22% (26.81%<CI 0.95<49.62%), and the titers ranged from 64 to 65536. The observed prevalence for N. caninum infection was 8.81% (7.08%<CI 0.95<10.53%). The titers ranged from 50 to 51200. The reactant sera to both pathogens corresponded
to 4.67% of the samples. The risk factors were not determined because of the absence of negative herds for T. gondii and the high proportion of positive herds for N. caninum (87.50%). The prevalence for T. gondii infection was significantly higher among males than in females. The present work is the first report on seroprevalence of
T. gondii and N. caninum in sheep from Federal District and shows that infection by both parasites is widespread in the ovine population from this
region. 相似文献
902.
Paschoalini Alessandro Loureiro Savassi Lourenço Almeida Weber André Alberto Moreira Davidson Peruci Ribeiro Yves Moreira Rizzo Elizete Bazzoli Nilo 《Fish physiology and biochemistry》2021,47(4):797-810
Fish Physiology and Biochemistry - In the last decades, oestrogenic compounds have often been reported in environmentally relevant concentrations in aquatic environments around the world. Most... 相似文献
903.
Rafael Augusto Vieira Carlos Alberto Scapim Lia Mara Moterle Dauri José Tessmann Antonio Teixeira do Amaral Júnior Leandro Simões Azeredo Gonçalves 《Euphytica》2012,185(3):325-336
The combining ability and genetic parameters of maize grown in two different environments of diseases pressure were estimated
for partial resistance to northern leaf blight (Exserohilum turcium, NLB) and gray leaf spot (Cercospora spp., GLS). Nine inbred lines were crossed in a complete diallel mating scheme including reciprocals. Two experiments were
carried out to test the hybrids using randomised complete blocks design with three replications during the growing season
2008/2009. The severities of NLB and GLS were assessed under natural infestation conditions. The first experiment was the
lowest NLB and GLS pressure environment, whereas the second was the highest. Data was evaluated using individual and joint
Griffing’s diallel analyses. General and specific combining abilities were significant (P < 0.10) for NLB and GLS resistance under both pressures. Although additive and nonadditive gene effects were significant,
the additive gene effects were more important for resistance to the diseases. The lines 1 (P83), 6 (P30F) and 7 (Pst) had the most outstanding general combining ability for NLB resistance, and the line 3 (P80) was outstanding for resistance to GLS. Based on both diseases resistance and grain yield, the synthetic composites 6 × 7 × 3
and (6 × 7) × 3 were recommended for intrapopulational breeding using recurrent selection. Three promising hybrid combinations
(the 3 × 6, and 5 × 7 for resistance to NLB, and 3 × 9 for resistance to GLS) were recommended for interpopulational breeding.
Resistance levels to NLB and GLS resistance were better discriminated under HP than LP conditions; however, promising lines
were detected under both pressures. 相似文献
904.
M. C. G. Gasparoto H. D. Coletta‐Filho R. B. Bassanezi S. A. Lopes S. A. Lourenço L. Amorim 《Plant pathology》2012,61(4):658-664
The objectives of this work were (i) to determine the influence of temperature on infection of citrus by ‘Candidatus Liberibacter asiaticus’ and ‘Candidatus Liberibacter americanus’, the two bacterial species associated with citrus huanglongbing (HLB) in Brazil, and (ii) to determine the influence of temperature on citrus colonization by ‘Ca. L. asiaticus’, which has taken over from ‘Ca. L. americanus’ as the predominant species in Brazil since 2008. Two experiments were carried out with graft‐inoculated Valencia oranges on Rangpur lime rootstocks. Immediately after inoculation the plants were maintained for 423 days in growth chambers under the following night/day temperature conditions: 17/22, 22/27 or 27/32°C, with a dark/light photoperiod of 8/16 h. Infection and colonization of plants were determined using quantitative PCR (qPCR). ‘Candidatus Liberibacter americanus’ did not infect the plants maintained at 27/32°C; however, infection by ‘Ca. L. asiaticus’ occurred at all studied temperatures. Two months after inoculation, ‘Ca. L. asiaticus’ was distributed throughout the inoculated plants, with mean Ct values in the range of 30–31 for leaves and 25–28 for roots. Over time, ‘Ca. L. asiaticus’ reached the highest titres in mature leaves (mean Ct value = 26·7) of citrus plants maintained at 22/27°C. ‘Candidatus Liberibacter asiaticus’ colonization of citrus plants was negatively affected by the daily temperature regime of 27/32°C (mean Ct value in mature leaves = 33·6). 相似文献
905.
A field study was conducted during 2005 and 2006 in Terra Quente, northeastern Portugal, to evaluate the efficacy of the spinosad-based insecticide Spintor Cebo® (Dow Agrosciences Ibérica, S.A.) against the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), as well as the impact of the treatments on non-target arthropods. Results suggest that this insecticide could be as effective as dimethoate and since it was reported as having more benign toxicological and ecological profiles, it seems to be a good alternative to control the pest in Continental Mediterranean climates such as Terra Quente. However, its use should be evaluated carefully, mainly in conditions that increase the arthropod biological control agents’ propensity for feeding on it (e.g. absence of pollen, nectar and honeydews) to identify unintended impacts on conservation biological control of olive pests as a result of its application. 相似文献
906.
Benjamin Richard Stéphane Jumel François Rouault Bernard Tivoli 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(3):367-379
On spring pea, ascochyta blight (Mycosphaerella pinodes) frequently appears at the plant base on yellowing stipules and disease scores are higher on basal parts of the plants than
on the uppermost parts. In order to investigate the relationship between pea plant growth stage and/or organ age, and ascochyta
blight on whole plants and detached stipules and pods, two experiments were conducted in 2009 and 2010 under controlled conditions.
This study showed that plant stage does not influence receptivity to ascochyta blight before the appearance of the first visual
signs of senescence (beginning of yellowing). When stipules were green, regardless of the plant stage, no differences of receptivity
was observed (except for the youngest stipule(s) at the top of the plant). Plant stage only had an effect on receptivity by
the way of the importance of the visual senescence of the organs and visual senescence has a more predominant effect on plant
receptivity than the plant stage considered alone. An effect of the nodal position, linked with the stipule age, was observed
on whole plant inoculation, with a decreasing disease severity gradient from the base to the top of the plant which was explained
by a greater receptivity for the basal/older stipules which had begun yellowing. On detached stipules, a higher receptivity
was observed as soon as visual senescence had been observed. On pods, during their filling, few symptoms appeared and severity
was important as soon as they began to yellow. The effect of ascochyta blight on induced senescence of the infected stipules
was also observed. 相似文献
907.
Baseline susceptibilities of B- and Q-biotype Bemisia tabaci to anthranilic diamides in Arizona 总被引:2,自引:0,他引:2
Li X Degain BA Harpold VS Marçon PG Nichols RL Fournier AJ Naranjo SE Palumbo JC Ellsworth PC 《Pest management science》2012,68(1):83-91
BACKGROUND: Development of pyriproxyfen and neonicotinoid resistance in the B-biotype whitefly and recent introduction of the Q biotype have the potential to threaten current whitefly management programs in Arizona. The possibility of integrating the novel anthranilic diamides chlorantraniliprole and cyantraniliprole into the current program to tackle these threats largely depends on whether these compounds have cross-resistance with pyriproxyfen and neonicotinoids in whiteflies. To address this question, the authors bioassayed a susceptible B-biotype strain, a pyriproxyfen-resistant B-biotype strain, four multiply resistant Q-biotype strains and 16 B-biotype field populations from Arizona with a systemic uptake bioassay developed in the present study. RESULTS: The magnitude of variations in LC50 and LC99 among the B-biotype populations or the Q-biotype strains was less than fivefold and tenfold, respectively, for both chlorantraniliprole and cyantraniliprole. The Q-biotype strains were relatively more tolerant than the B-biotype populations. No correlations were observed between the LC50 (or LC99) values of the two diamides against the B- and Q-biotype populations tested and their survival rates at a discriminating dose of pyriproxyfen or imidacloprid. CONCLUSION: These results indicate the absence of cross-resistance between the two anthranilic diamides and the currently used neonicotinoids and pyriproxyfen. Future variation in susceptibility of field populations to chlorantraniliprole and cyantraniliprole could be documented according to the baseline susceptibility range of the populations tested in this study. Copyright © 2011 Society of Chemical Industry 相似文献
908.
Heuskin S Lorge S Godin B Leroy P Frère I Verheggen FJ Haubruge E Wathelet JP Mestdagh M Hance T Lognay G 《Pest management science》2012,68(1):127-136
BACKGROUND: Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting predators and parasitoids of aphids. Various formulation criteria were optimised with respect to semiochemical encapsulation capacity. Moreover, the optimised formulation was characterised by texturometry and confocal microscopy. The slow-release rates of semiochemicals were calculated in laboratory controlled conditions. The attractiveness of semiochemical formulations towards Aphidius ervi was demonstrated by olfactometry. RESULTS: Two major parameters were highlighted in encapsulation optimisation: the type of alginate (Sigma L) and the type of crosslinker ion (Ca2+). Other formulation parameters were optimised: ionic strength (0.5 M), Ca2+ (0.2 M) and alginate (1.5%) concentrations and the maturation time of beads in CaCl2 solution (48 h). After physical characterisation of beads, semiochemical slow-release measurements showed that alginate formulations were efficient sesquiterpene releasers, with 503 µg of E-β-farnesene and 1791 µg of E-β-caryophyllene totally released in 35 days. The efficiency of semiochemical alginate beads as attractants for female parasitoids was demonstrated, with high percentages of attraction for semiochemical odours (88 and 90% for E-β-farnesene and E-β-caryophyllene respectively) and significant statistical results. CONCLUSION: Semiochemical alginate beads can be considered as efficient slow-release systems in biological control. These formulations could be very useful to attract aphid parasitoids on crop fields. Copyright © 2011 Society of Chemical Industry 相似文献
909.
Nelson MR Wegmann D Ehm MG Kessner D St Jean P Verzilli C Shen J Tang Z Bacanu SA Fraser D Warren L Aponte J Zawistowski M Liu X Zhang H Zhang Y Li J Li Y Li L Woollard P Topp S Hall MD Nangle K Wang J Abecasis G Cardon LR Zöllner S Whittaker JC Chissoe SL Novembre J Mooser V 《Science (New York, N.Y.)》2012,337(6090):100-104
Rare genetic variants contribute to complex disease risk; however, the abundance of rare variants in human populations remains unknown. We explored this spectrum of variation by sequencing 202 genes encoding drug targets in 14,002 individuals. We find rare variants are abundant (1 every 17 bases) and geographically localized, so that even with large sample sizes, rare variant catalogs will be largely incomplete. We used the observed patterns of variation to estimate population growth parameters, the proportion of variants in a given frequency class that are putatively deleterious, and mutation rates for each gene. We conclude that because of rapid population growth and weak purifying selection, human populations harbor an abundance of rare variants, many of which are deleterious and have relevance to understanding disease risk. 相似文献
910.
François Chiron Ondine Filippi-Codaccioni Vincent Devictor 《Biological conservation》2010,143(11):2609-2616
Increasing habitats diversity in agricultural landscapes has been proposed as a key measure for reversing the decline of farmland biodiversity in Europe. However, indicators used for assessing such a potential compensation effect usually only rely on species diversity and abundance while ignoring variations in species-specific vulnerability. The extent to which habitat diversity may reverse the decline of specialist species in Europe to farming systems is thus still unclear. In this study, we investigate whether the effect of non-cropped habitat diversity on farmland birds’ occurrences was dependent on species’ specialization for habitats. In particular, we focused on the relative effects of non-cropped habitat diversity on species’ abilities to persist or to colonize new vacant areas. We used a capture-recapture statistical framework to study the spatial dynamics of 20 farmland bird species in France monitored from 2001 to 2007. We found that non-cropped landscape diversity reduces both the probabilities that a species becomes extinct locally and that a species colonizes new vacant areas, and the occupancy rate. Although this suggests a possible stabilizing effect of the surrounding habitat diversity on species occurrence in farming systems, the occupancy was only weakly affected. Moreover, we found that the most specialist species were the more negatively affected by this landscape diversity in terms of colonization abilities. We argue that accounting for the differences in habitat specialization among farmland species can improve conservation policies dedicated to the management of landscape diversity. 相似文献