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51.
Smith AD Brown CJ Bulman CM Fulton EA Johnson P Kaplan IC Lozano-Montes H Mackinson S Marzloff M Shannon LJ Shin YJ Tam J 《Science (New York, N.Y.)》2011,333(6046):1147-1150
Low-trophic level species account for more than 30% of global fisheries production and contribute substantially to global food security. We used a range of ecosystem models to explore the effects of fishing low-trophic level species on marine ecosystems, including marine mammals and seabirds, and on other commercially important species. In five well-studied ecosystems, we found that fishing these species at conventional maximum sustainable yield (MSY) levels can have large impacts on other parts of the ecosystem, particularly when they constitute a high proportion of the biomass in the ecosystem or are highly connected in the food web. Halving exploitation rates would result in much lower impacts on marine ecosystems while still achieving 80% of MSY. 相似文献
52.
Pemphigus foliaceous (PF) is a pustular, immune-mediated skin disease characterised by acantholytic cells and commonly treated with high doses of glucocorticoids. This report describes one case of feline PF successfully controlled using oral oclacitinib, suggesting a possible therapeutic alternative to glucocorticoids in some cases. 相似文献
53.
54.
King MR White BA Blaschek HP Chassy BM Mackie RI Cann IK 《Journal of agricultural and food chemistry》2002,50(20):5676-5682
Food ingredients containing alpha-1,6-galactoside bonds elicit gastrointestinal disturbances in monogastric animals, including humans. Pretreatment of such ingredients with alpha-galactosidase (EC 3.2.1.22) has the potential to alleviate this condition. For this purpose, a thermostable alpha-galactosidase from Thermoanaerobacterium polysaccharolyticum was purified by a combination of anion exchange and size exclusion chromatographies. The enzyme has a monomeric molecular weight of approximately 80 kDa; however, it is active as a dimer. The optimum temperature for enzyme activity is 77.5 degrees C. Approximately 84 and 88% of enzyme activity remained after 36.5 h of incubation at 70 and 65 degrees C, respectively. Optimum activity was observed at pH 8.0, with a broad range of activity from pH 5.0 to 9.0. Different transition metals had weak to strong inhibitory effects on enzyme activity. The K(m) and V(max) of the enzyme are 0.29-0.345 mM and 200-232 micromol/min/mg of protein, respectively. Importantly, enzyme activity was only slightly inhibited by 75-100 mM galactose, an end product of hydrolysis. Enzyme activity was specific for the alpha-1,6-galactosyl bond, and activity was demonstrated on melibiose and soy molasses. 相似文献
55.
Assessment of the uniformity of wheat and tomato varieties at DNA microsatellite loci 总被引:9,自引:1,他引:9
R.J. Cooke G.M.M. Bredemeijer M.W. Ganal R. Peeters P. Isaac S. Rendell J. Jackson M.S. Röder V. Korzun K. Wendehake T. Areshchenkova M. Dijcks D. Laborie L. Bertrand B. Vosman 《Euphytica》2003,132(3):331-341
By analysing a number (20–38) of individuals from selected varieties of wheat and tomato, we have been able to assess intra-varietal
uniformity at certain micro satellite (simple sequence repeat, SSR) loci. In total, 45 varieties of wheat were analysed at
between 7–9 different SSR loci, and 10 varieties of tomato were analysed at six loci. The results showed that there was variation
both between varieties and between microsatellites in the degree of non-uniformity observed, and it was possible to identify
a number of different probable sources of non-uniformity. Twenty-four of the wheat varieties and nine of the tomato varieties
were sufficiently uniform to meet the standards currently applied for distinctness, uniformity and stability (DUS) testing
using phenotypic characteristics. The implications for the potential future use of SSRs in DUS testing are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
56.
Marney E. Isaac Eric O. Adjei Roland N. Issaka Vic R. Timmer 《Agroforestry Systems》2011,81(2):147-155
Shade tolerant species response to nutrient additions and light regulation by canopy trees in perennial agroforestry systems
has been well documented. However, accelerated early growth, particularly in cocoa-shade systems, may be offset by competition
for limited resources on nutrient poor sites. To date, few agroforestry management strategies focus on nutrient manipulation
of the shade tree component or strategies for precision nutrient application. Our research objective was to diagnose interactions
between nutrient supplied shade trees intercropped with cocoa. We established greenhouse trials in Kwadaso, Ghana cultivating
Terminalia superba seedlings with four fertility treatment levels: conventional rate (current practices) under linear additions, and half, full
and double conventional rate under exponential additions (steady-state nutrition) to determine maximal growth and nutrient
uptake. After 4 months of additions in the nursery, pre-fertilized T. superba seedlings were then out-planted into field trials with cocoa seedlings. After 4 months of intercropping, cocoa associated
with half rate exponentially supplied T. superba had significantly larger leaf area, greater leaf number, and higher nutrition (N and P uptake) than cocoa associated with
full rate conventionally supplied T. superba. This may be attributed to (1) more favorable light conditions under these taller shade seedlings and (2) the internal use
of nutrients associated with exponentially supplied T. superba seedlings, which lowered stress on native soil resources. The latter is corroborated with our findings on soil fertility
status. This strategy focused on reducing fertilizer inputs and developing precise plant nutrition technology for on-farm
use. Our findings suggest that shade seedlings under steady state nutrition can mitigate early growth competition in the field. 相似文献
57.
Flufenerim, a novel insecticide acting on diverse insect pests: biological mode of action and biochemical aspects 总被引:1,自引:0,他引:1
Ghanim M Lebedev G Kontsedalov S Ishaaya I 《Journal of agricultural and food chemistry》2011,59(7):2839-2844
A new chemical compound was tested for its insecticidal activity against several major insect pests. The compound, called "flufenerim", has a core pyrimidine structure and an unknown mode of action and showed potent activity against the sweet potato whitefly Bemisia tabaci (Gennadius), the green peach aphid Myzus persicae (Sulzer), and the African cotton leafworm Spodoptera littoralis (Boisduval); however, it did not show any activity against two thrips species: western flower thrips Frankliniella occidentalis (Pergande) and tobacco thrips Thrips tabaci (Lindeman). The compound was relatively potent against the three tested pests and caused mortality rates that reached up to 100% at concentrations under 10 mg of active ingredient (ai) L(-1). The action of the compound was very fast, and mortality was observed within 48 h after exposure of the insects to treated leaves. A unique characteristic of this compound is its very short residual activity, which approximates to 4 days after application under laboratory conditions and to 2 days under outdoor conditions for both B. tabaci and S. littoralis. Although this new compound's mode of action is yet unknown, its rapid and potent action against sap-sucking pests suggests that it acts on a very important target site in the insect body and possibly could be applied very close to harvesting. 相似文献
58.
Makoto N. Masuno Alexander C. Hoepker Isaac N. Pessah Tadeusz F. Molinski 《Marine drugs》2004,2(4):176-184
Two new sulfate monoesters of hemibastadins-1 and -2 were isolated from the marine sponge Ianthella basta (Pallas) from Guam. A third new compound was tentatively assigned the structure 34-O-sulfatobastadin-9. The 1-O-sulfatohemibastadins-1 and –2 were antagonists of the RyR1-FKBP12 Ca2+ channel under conditions where the known compound bastadin-5 exhibits potent agonism (EC50 2 μM). 相似文献
59.
Isaac K. Mpanga Günter Neumann Judith K. Brown Joseph Blankinship Russell Tronstad Omololu Idowu 《植物养料与土壤学杂志》2023,186(3):276-285
Background
Grape pomace (GP) is a by-product of wineries after filtering the grape juice for wine production. GP contains seeds, pulp, skin, and stalks with acidic properties, and it is normally composted before using as a soil amendment. However, composting GP requires more time, labor, and equipment; furthermore, composting loses some of the desirable organic acids for arid soils. The acidic properties of these organic acids and the plant nutrients in GP make it a desirable amendment for arid soils in both non-composted and composted forms.Aim
This study investigates the potential of directly applying GP as a soil amendment and its impact on arid soil health and plant performance.Methods
To test the potential of non-composted GP as a soil amendment, greenhouse and field studies were conducted by combining GP with existing management practices (manure application for soil used in the greenhouse study and fertigation for the field study) to assess the effects of GP on soil health and crop (maize, wheat, and grape) performance.Results
Adding 5% GP to an alkaline soil significantly increased maize and wheat growth and shoot nutrient concentrations in the greenhouse and grapes in the field (48% yield increase). The significance of GP on maize, wheat, and grapes was associated with soil nutrient enhancements (i.e., nutrients supplied, increase in organic matter and microbial biomass increase, reduction in pH, and better nutrient mobilization).Conclusion
GP has the potential for direct use as a soil amendment for soil and crop health improvement, especially in arid soils with high pH and limited soil organic matter. 相似文献60.
Wirgin I Roy NK Loftus M Chambers RC Franks DG Hahn ME 《Science (New York, N.Y.)》2011,331(6022):1322-1325
The mechanistic basis of resistance of vertebrate populations to contaminants, including Atlantic tomcod from the Hudson River (HR) to polychlorinated biphenyls (PCBs), is unknown. HR tomcod exhibited variants in the aryl hydrocarbon receptor 2 (AHR2) that were nearly absent elsewhere. In ligand-binding assays, AHR2-1 protein (common in the HR) was impaired as compared to widespread AHR2-2 in binding TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and in driving expression in reporter gene assays in AHR-deficient cells treated with TCDD or PCB126. We identified a six-base deletion in AHR2 as the basis of resistance and suggest that the HR population has undergone rapid evolution, probably due to contaminant exposure. This mechanistic basis of resistance in a vertebrate population provides evidence of evolutionary change due to selective pressure at a single locus. 相似文献