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991.
Pozo-Bayón MA G-Alegría E Polo MC Tenorio C Martín-Alvarez PJ Calvo de la Banda MT Ruiz-Larrea F Moreno-Arribas MV 《Journal of agricultural and food chemistry》2005,53(22):8729-8735
Red wine amino acids and volatile compounds were analyzed before and after malolactic fermentation carried out by four different starter cultures of the species Oenococcus oeni and Lactobacillus plantarum. The purpose of this study was to determine whether differences can be attributed to the lactic acid bacteria strain used in this important step of the wine-making process. The malolactic cultures selected for this study were indigenous wine lactic acid bacteria strains. The data were evaluated using different multivariate analysis techniques. Results showed different malolactic behaviors for O. oeni and L. plantarum and significant metabolic differences between both species. A degree of diversity was found within each lactic acid bacteria group, since wines presented specific characteristics depending on the lactic acid bacteria strain used. In all cases, malolactic fermentation seemed to modify the amino acid and volatile composition of the wine. 相似文献
992.
A protein fraction with peroxidase (EC 1.11.1.7) activity against guaiacol from Beta vulgaris L. roots oxidized both betanidin and betanin (betanidin 5-O-beta-D-glucoside), the former being the more efficient substrate for the enzyme. The protein fraction contained three strongly basic perxidase isoenzymes. Betanidin quinone was formed as the only product in the course of enzymatic betanidin oxidation, whereas betalamic acid and several oxidized cyclo-DOPA 5-O-beta-D-glucoside polymers were generated during the oxidation of betanin. In accordance with the catalytic properties of peroxidase, a possible mechanism for betanidin oxidation is proposed. This mechanism includes the formation of a betanidin radical, which, by further dismutation, yields betanidin quinone and betanidin. The betanidin oxidation rate showed a Michaelis-type dependence on the substrate concentration. The apparent K(M) for the reaction was 0.46 mM. On the basis of the spectral properties of the enzyme responsible for both betanidin and betanin oxidations, its peroxidase nature is suggested. 相似文献
993.
Arsenic species: effects on and accumulation by tomato plants. 总被引:7,自引:0,他引:7
F Burló I Guijarro A A Carbonell-Barrachina D Valero F Martínez-Sánchez 《Journal of agricultural and food chemistry》1999,47(3):1247-1253
The uptake of arsenic (As) species by Lycopersicum esculentum, growing under soilless culture conditions, was studied. A 4 x 3 x 2 factorial experiment was conducted with four As species (arsenite, arsenate, methylarsonate, and dimethylarsinate), three As concentrations (1, 2, and 5 mg L(-)(1)) and two tomato cultivars (Marmande and Muchamiel). The phytoavailability and phytotoxicity were primarily determined by the As species. The concentrations of As in plant increased significantly with increasing As concentration in solution. Both MA and DMA showed a higher upward translocation than arsenite and arsenate, and treatments with MA and DMA clearly reduced plant growth and fruit yield. The As concentration in tomatoes treated with arsenite or arsenate were within the range considered normal in food crops; however, the As concentration in tomatoes treated with MA and DMA were close to or even above the maximum limit. When tomato plants are exposed to high concentrations of As in nutrient solutions, they may uptake As to concentrations unacceptable for human food. 相似文献
994.
Rodríguez García JC Iglesias Rodríguez R Peña Crecente RM Barciela García J García Martín S Herrero Latorre C 《Journal of agricultural and food chemistry》2006,54(19):7206-7212
Thirteen metal elements were determined in 40 honey samples from Galicia with different environmental origins: rural, urban, and industrial areas. The data set of the honey metallic profiles was studied with a double purpose: first, to make a preliminary evaluation of honey as an environmental indicator in Galicia with the aim of monitoring pollution and, second, to compare the different capabilities of diverse pattern recognition prediction procedures for modeling the environmental surrounding of the hive. A certain level of similarity for urban and industrial samples was obtained using principal component analysis and cluster analysis, whereas significant differences for urban and industrial honeys were found in relation to rural honey samples. Different classification rules to associate metal content of honeys with their environmental surrounding were obtained by chemometric pattern recognition procedures. In general, the classification methods developed by neural networks provided better results than the traditional pattern recognition procedures. The metal profiles of honey seem to provide sufficient information to enable categorization criteria for classifying samples according to their environmental surrounding. Thus, honey could be a potential pollution indicator for the Galician area. 相似文献
995.
Elena Palacios Ilie S. Racotta Benjamín Aparicio Olivia Arjona Carlos A. Martínez-Palacios 《Fish physiology and biochemistry》2007,33(1):81-91
Lipid classes and fatty acid levels were analyzed in freshly fertilized eggs, early and late embryo development, and freshly
hatched larvae obtained from wild and captive silverside Chirostoma estor estor broodstock, as well as in plankton, Artemia, and pelleted feed. The concentration of triglycerides (TGs) and highly unsaturated fatty acids (HUFAs) in neutral lipid
fraction significantly decreased during early development and especially after hatching, whereas phospholipids and HUFA in
polar lipid fraction remained constant. These results indicate that TGs rather than PLs are used as energy sources and that
all HUFAs [20:4n-6/arachidonic acid (ARA), 20:5n-3/eicosapentaenoic acid (EPA), and 22:6n-3/docosahexaenoic acid (DHA)] of
polar lipids are selectively conserved during early development. High levels of DHA (30%, on average, of total fatty acids)
and low levels of EPA (4%) were observed in eggs, embryos, and larvae and did not reflect the proportions of these fatty acids
in food. Preferential accumulation of DHA from food consumed by broodstock, and then transference to eggs, was probably occurring.
The main difference between eggs from both origins was a low level of ARA in eggs from captive fish (4% of total fatty acids)
compared to wild fish (9%). This could be associated with a deficiency in the diet that is not compensated for by desaturation/elongation
of 18:2n-6 and, possibly, with greater stress in captive fish. In any case, particular requirements of ARA should be determined
to optimize the culture of C. estor. 相似文献
996.
997.
998.
Climate-growth variability in Quercus ilex L. west Iberian open woodlands of different stand density
Guillermo Gea-Izquierdo Dario Martín-Benito Paolo Cherubini Isabel Cañellas 《Annals of Forest Science》2009,66(8):802-802
999.
Lesions of variable size, associated with the hymenomycete Inocutis jamaicensis, a white‐rot fungus, have been observed on the stems of Eucalyptus globulus trees in Uruguay. The aim of this study was to evaluate some ecophysiological characteristics of I. jamaicensis and assess its ability to colonize E. globulus trees of two different seed origins (Geeveston and Jeeralang) and the clone, 334‐1‐AR, obtained by micropropagation (ENCE, Spain). The growth of an I. jamaicensis isolate (MVHC11379) was evaluated at 25°C in a medium with a water potential of 0 (Ψ = 0). The growth rate did not vary significantly with a growth medium pH of between 4 and 7. I. jamaicensis showed no growth at either 5 or 37°C at any pH or Ψ tested. Weight loss of heartwood and sapwood of different plant provenances inoculated with I. jamaicensis under laboratory conditions was evaluated, and significant differences observed. Lignin‐modifying enzyme activity was evaluated in culture medium with or without E. globulus sawdust as substrate or inducer. Laccase activity was observed with sawdust and manganese peroxidase activity with and without sawdust. Only slight activity of aryl‐alcohol oxidase and lignin peroxidase was detected without sawdust. Experimental inoculation with I. jamaicensis of 3‐year‐old Geeveston and Jeeralang, and of 4‐year‐old 334‐1‐AR stems, resulted in successful fungal colonization of 56% of the 334‐1‐AR, 50% of Geeveston and 25% of Jeeralang trees. Only the heartwood was decayed. In 334‐1‐AR, the rotted wood was delimited by a reaction zone. Wood characteristics and the ability of I. jamaicensis to overcome the chemical reactions in the tree could partially explain differences in susceptibility to the fungus among provenances observed under natural and laboratory conditions. 相似文献
1000.
A new cyclic diamine, 1,5-diazacyclohenicosane (1), was isolated from samples of the marine sponge Mycale sp. collected at Lamu Island (Kenya). Its structure was determined by a combination of spectroscopic techniques, including (+)-HRESIMS and 1D and 2D NMR spectroscopy. The compound displayed cytotoxicity at the μM level against three human tumor cell lines. 相似文献