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991.
Activity-guided fractionation of the methanol extract of Ebenus pinnata aerial parts led to the isolation of ombuoside (1), kaempferol 3-O-rutinoside (2), rutin (3), catechin (4), and picein (5), along with beta-sitosterol and beta-sitosterol glucoside. Compounds 1-4 showed significant antioxidant activity in the DPPH, and TEAC, reducing power assays. 相似文献
992.
Khalid Majourhat Youssef Jabbar Abdellatif Hafidi Pedro Martínez-Gómez 《Annals of Forest Science》2008,65(8):805-805
993.
Assessment of vineyard water status variability by thermal and multispectral imagery using an unmanned aerial vehicle (UAV) 总被引:3,自引:0,他引:3
Javier Baluja Maria P. Diago Pedro Balda Roberto Zorer Franco Meggio Fermin Morales Javier Tardaguila 《Irrigation Science》2012,30(6):511-522
The goal of this study was to assess the water status variability of a commercial rain-fed Tempranillo vineyard (Vitis vinifera L.) by thermal and multispectral imagery using an unmanned aerial vehicle (UAV). The relationships between aerial temperatures or indices derived from the imagery and leaf stomatal conductance (g s) and stem water potential (Ψstem) were determined. Aerial temperature was significantly correlated with g s (R 2?=?0.68, p?<?0.01) and Ψstem (R 2?=?0.50, p?<?0.05). Furthermore, the thermal indices derived from aerial imagery were also strongly correlated with Ψstem and g s. Moreover, different spectral indices were related to vineyard water status, although NDVI (normalized difference vegetation index) and TCARI/OSAVI (ratio between transformed chlorophyll absorption in reflectance and optimized soil-adjusted vegetation index) showed the highest coefficient of determination with Ψstem (R 2?=?0.68, p?<?0.05) and g s (R 2?=?0.84, p?<?0.05), respectively. While the relationship with thermal imagery and water status parameters could be considered as a short-term response, NDVI and TCARI/OSAVI indices were probably reflecting the result of cumulative water deficits, hence a long-term response. In conclusion, thermal and multispectral imagery using an UAV allowed assessing and mapping spatial variability of water status within the vineyard. 相似文献
994.
995.
Pedro Henrique Monteiro do Amaral Lidimara Souza da Silveira Beatriz Figueiraujo Jabour Vescovi Rosa Vívian Campos de Oliveira Roberto da Gama Alves 《Journal of insect science (Online)》2015,15(1)
Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages’ insects can differ between these habitats and influence the results of assessments in low-order streams. 相似文献
996.
Viviana Marcela Camelo-García Élison Fabricio B. Lima Pedro Javier Mansilla-Córdova Jorge Alberto Marques Rezende Elliot Watanabe Kitajima Modesto Barreto 《Journal of General Plant Pathology》2014,80(3):282-286
A high incidence of plants with mosaic, chlorotic spots, ringspots, necrosis, smaller leaves, and stunting was observed on peanut crops (Arachis hypogaea L.) in Itápolis, São Paulo State, Brazil. Transmission electron microscope examination of thin sections of infected leaves revealed the presence of spheroidal particles, ca. 80 nm in diameter, suggestive of Tospovirus. A DNA fragment of ~600 bp was amplified by RT-PCR from total RNA extracted from infected tissues using primers specific for the nucleocapsid gene of Groundnut ringspot virus (GRSV). Nucleotide and deduced amino acid sequences of the fragments showed high identities with known GRSV isolates. 相似文献
997.
998.
Animals have developed a range of drinking strategies depending on physiological and environmental constraints. Vertebrates with incomplete cheeks use their tongue to drink; the most common example is the lapping of cats and dogs. We show that the domestic cat (Felis catus) laps by a subtle mechanism based on water adhesion to the dorsal side of the tongue. A combined experimental and theoretical analysis reveals that Felis catus exploits fluid inertia to defeat gravity and pull liquid into the mouth. This competition between inertia and gravity sets the lapping frequency and yields a prediction for the dependence of frequency on animal mass. Measurements of lapping frequency across the family Felidae support this prediction, which suggests that the lapping mechanism is conserved among felines. 相似文献
999.
Emilio R. Diaz-Varela Manuel F. Marey-Pérez Antonio Rigueiro-Rodriguez Pedro Álvarez-Álvarez 《Annals of Forest Science》2009,66(3):301-301
1000.
Developmental thresholds and thermal requirements for development of post-dormancy larvae of Monochamus galloprovincialis (Olivier) (Cerambycidae; Monochamini) were studied at ten constant temperatures ranging from 7 to 35°C. The relationship
between temperature and development duration in days was linear between 15 and 30°C (r
2
= 0.98). The lower threshold for development was determined to be 12.2 ± 0.8°C and an average of 822 degree-days (DD) above
that value was required for 50% adult emergence under laboratory conditions. The rate of larval development decreased above
30°C and the lethal upper threshold was between 32 and 35°C. Degree-day rate summation was initiated in the first of March
and model predictions were validated with records of field emergence for the years 2001 to 2004. The modified sine wave predicted
median emergence with an average error of 3.8 days from emergences in the field and a zero-day difference for two of the years.
Model predictions were always within 10% of actual observed emergences. Predictions for early emergences (cumulative percentiles
1 and 10) were less accurate than predictions for median and late emergencies. The results suggest that a simple linear method
driven by air temperatures can predict the emergence of M. galloprovincialis with sufficient accuracy to improve the pest management programmes currently implemented on the pine wilt disease affected
zone in Portugal. 相似文献