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281.
Storage research, especially at small-farm level, makes too little impact on policy, largely for want of evidence that the benefits of grain savings – especially to the poor and hungry – justify the costs of improved structures. The paper describes a pilot survey of the costs and benefits of alternative means of paddy storage in two South Indian villages. Preliminary results suggest that subsequent, ongoing work in a larger sample of villages will justify substantial outlays on improved stores for small farmers and even landless labourers. 相似文献
282.
Contribution of trees to soil carbon sequestration under agroforestry systems in the West African Sahel 总被引:1,自引:0,他引:1
Consequent to recent recognition of agricultural soils as carbon (C) sinks, agroforestry practices in the West African Sahel
(WAS) region have received attention for their C sequestration potential. This study was undertaken in the Ségou region of
Mali that represents the WAS, to examine the extent of C sequestration, especially in soils, in agroforestry systems. Five
land-use systems were selected in farmers’ fields [two traditional parkland systems, two improved agroforestry systems (live
fence and fodder bank), and a so-called abandoned land]. Soil samples taken from three depths (0–10 cm, 10–40 cm, and 40–100 cm)
were fractionated into three size classes (2,000–250 μm, 250–53 μm, and <53 μm) and their C contents determined. Whole-soil
C contents, g kg−1 soil, across three depths ranged from 1.33–4.69 in the parklands, 1.11–4.42 in live fence, 1.87–2.30 in fodder bank, and
3.69–5.30 in abandoned land; and they correlated positively with silt + clay content. Using the 13C isotopic ratio as an indicator of relative contribution of trees (C3 plants) and crops (C4 plants) to soil C, more tree-origin
C was found in larger particle size and surface soil and indicated that long-term tree presence promoted storage of protected
C in deeper soil. Existing long-standing agroforestry practices of the region such as the parklands seemed to have little
advantage for sequestering additional C, whereas improved agroforestry practices such as live fence and fodder bank introduced
in treeless croplands seemed to be advantageous. 相似文献
283.
Baseline sensitivity of maize borers in India to the Bacillus thuringiensis insecticidal proteins Cry1A.105 and Cry2Ab2
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Phenotypic and genotypic characterization of bovine mastitis isolates of Staphylococcus aureus for biofilm formation 总被引:1,自引:0,他引:1
Staphylococcus aureus is one of the most common pathogens responsible for contagious mastitis in ruminants. The ability of S. aureus to form biofilm in vivo is considered to be a major virulence factor influencing its pathogenesis in mastitis. The objectives of the study were to examine in vitro slime production, biofilm formation, and the presence of the ica gene locus and icaA and icaD genes in S. aureus isolates from bovine mastitis. Thirty-two of the 35 isolates tested produced slime on Congo red agar, whereas only 24 of the isolates were found to produce biofilm in vitro. However, all the 35 isolates possessed the ica locus, icaA and icaD genes. This study indicates a high prevalence of the ica genes among S. aureus mastitis isolates, and their presence is not always associated with in vitro formation of slime or biofilm. A combination of phenotypic and genotypic tests is recommended for investigating biofilm formation in S. aureus. 相似文献
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L. -A. Appelqvist Baboo M. Nair 《Plant foods for human nutrition (Dordrecht, Netherlands)》1977,27(3-4):265-273
There are considerable differences in amino acid pattern between the seed coat and the embryo (separated after 5 h of imbibition in water) but only minor differences between the various embryonic parts, the hypocotyl, the inner and outer cotyledons. Thus, the seed coat is high in proline and hydroxyproline and relatively low in glutamic acid. No change in amino acid pattern was observed in the cotyledons after an additional 19 h of imbibition. This is of pratical significanse since a separation of the seed parts — of value in genetic studies — is greatly simplified if performed with swollen seeds as compared with dry seeds.The variation in the amino acid composition among single seeds of heterozygousB. campestris was higher than the variation among single seeds of homozygousB. tournfortii.
Zusammenfassung Es bestehen bedeutende Unterschiede im Aminosäuremuster der Samenschale und des Embryos (getrennt nach 5 Stunden Inhibition in Wasser) aber nur geringere zwischen den verschiedenen Teilen des Embryos, dem Hypocotyl und den inneren und äusseren Cotyledonen. So sind die Gehalte der Samenschale hoch an Prolin und Hydroxyprolin sowie relativ niedrig an Glutaminsäure. Keine Anderung trat im Aminosäuren-Muster der Cotyledonen ein, wenn sie einer weiteren 19 Stunden-Inhibition unterworfen wurden. Dies ist von praktischer Bedeutung, da eine Trennung der Samenbestandteilewichtig für genetische Studien-im inhibierten Zustand sstärker vereinfacht wird als im normalen trockenen Zustand.Die Variation des Aminosäuren-Spektrums zwischen einzelnen Samen vonBrassica campestris-Heterozygoten war gröszer als die der Heterozygoten vonBrassica tournefortii.
Résumé Il y a des différences considérables dans la composition en aminoacides entre le tégument séminal et l'embryon (séparé après 5h d'imbibition dans l'eau); par contre il y a peu de différences entre les diverses parties de l'embryon, l'hypocotyle, l'intérieur des cotylectons. Ainsi le tégument séminal est riche en proline et hydroxyproline, et relativement pauvre en acideglutamique. Aucun changement dans les taux d'amincides n'a été observé lors d'une imbibition supplémentaire de 19 heures.Ce fait a une importance pratique, car la séparation de la graine en ses diverses parties — importante dans les recherches génétiques — est grandement simplifiée si elle est pratiquée sur des graines gonflées et non sur des graines sèches. La variation du taux d'aminoacides entre graines isollées deB. campestris hétérozygote était plus grande que chez les graines homozygotes deB. tournefortii.相似文献
290.