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排序方式: 共有89条查询结果,搜索用时 15 毫秒
81.
Regeneration of ammonia borane spent fuel by direct reaction with hydrazine and liquid ammonia 总被引:1,自引:0,他引:1
Sutton AD Burrell AK Dixon DA Garner EB Gordon JC Nakagawa T Ott KC Robinson JP Vasiliu M 《Science (New York, N.Y.)》2011,331(6023):1426-1429
Ammonia borane (H(3)N-BH(3), AB) is a lightweight material containing a high density of hydrogen (H(2)) that can be readily liberated for use in fuel cell-powered applications. However, in the absence of a straightforward, efficient method for regenerating AB from dehydrogenated polymeric spent fuel, its full potential as a viable H(2) storage material will not be realized. We demonstrate that the spent fuel type derived from the removal of greater than two equivalents of H(2) per molecule of AB (i.e., polyborazylene, PB) can be converted back to AB nearly quantitatively by 24-hour treatment with hydrazine (N(2)H(4)) in liquid ammonia (NH(3)) at 40°C in a sealed pressure vessel. 相似文献
82.
Caitlin K. Frankish Andrea Manica Joan Navarro Richard A. Phillips 《水产资源保护:海洋与淡水生态系统》2021,31(7):1715-1729
- Many seabirds dive to forage, and the ability to use this hunting technique varies according to such factors as morphology, physiology, prey availability, and ambient light levels. Proficient divers are more able to seize sinking baits deployed by longline fishing vessels and may return them to the surface, increasing exposure of other species. Hence, diving ability has major implications for mitigating incidental mortality (bycatch) in fisheries.
- Here, the diving behaviour and activity patterns of the most bycaught seabird species worldwide, the white-chinned petrel (Procellaria aequinoctialis), tracked from Bird Island (South Georgia), are analysed. Three data sources (dives, spatial movements, and immersion events) are combined to examine diverse aspects of at-sea foraging behaviour, and their implications for alternative approaches to bycatch mitigation are considered.
- The tracked white-chinned petrels (n = 14) mostly performed shallow dives (<3 m deep) of very short duration (<5 s), predominantly during darkness, but only 7 and 10% of landings in daylight and darkness, respectively, involved diving, suggesting that surface-seizing is the preferred foraging technique. Nonetheless, individuals were able to dive to considerable depth (max = 14.5 m) and at speed (max = 2.0 m·s−1), underlining the importance of using heavy line-weighting to maximize hook sink rates, and bird-scaring lines (Tori lines) that extend for long distances behind vessels to protect hooks until beyond diving depths.
83.
Walsh T McClellan JM McCarthy SE Addington AM Pierce SB Cooper GM Nord AS Kusenda M Malhotra D Bhandari A Stray SM Rippey CF Roccanova P Makarov V Lakshmi B Findling RL Sikich L Stromberg T Merriman B Gogtay N Butler P Eckstrand K Noory L Gochman P Long R Chen Z Davis S Baker C Eichler EE Meltzer PS Nelson SF Singleton AB Lee MK Rapoport JL King MC Sebat J 《Science (New York, N.Y.)》2008,320(5875):539-543
Schizophrenia is a devastating neurodevelopmental disorder whose genetic influences remain elusive. We hypothesize that individually rare structural variants contribute to the illness. Microdeletions and microduplications >100 kilobases were identified by microarray comparative genomic hybridization of genomic DNA from 150 individuals with schizophrenia and 268 ancestry-matched controls. All variants were validated by high-resolution platforms. Novel deletions and duplications of genes were present in 5% of controls versus 15% of cases and 20% of young-onset cases, both highly significant differences. The association was independently replicated in patients with childhood-onset schizophrenia as compared with their parents. Mutations in cases disrupted genes disproportionately from signaling networks controlling neurodevelopment, including neuregulin and glutamate pathways. These results suggest that multiple, individually rare mutations altering genes in neurodevelopmental pathways contribute to schizophrenia. 相似文献
84.
Barnes JW Brown RH Turtle EP McEwen AS Lorenz RD Janssen M Schaller EL Brown ME Buratti BJ Sotin C Griffith C Clark R Perry J Fussner S Barbara J West R Elachi C Bouchez AH Roe HG Baines KH Bellucci G Bibring JP Capaccioni F Cerroni P Combes M Coradini A Cruikshank DP Drossart P Formisano V Jaumann R Langevin Y Matson DL McCord TB Nicholson PD Sicardy B 《Science (New York, N.Y.)》2005,310(5745):92-95
Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80 degrees W and 20 degrees S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Science Subsystem. We discuss various hypotheses about the source of the spot, reaching the conclusion that the spot is probably due to variation in surface composition, perhaps associated with recent geophysical phenomena. 相似文献
85.
86.
Boon CS Xu Z Yue X McClements DJ Weiss J Decker EA 《Journal of agricultural and food chemistry》2008,56(4):1408-1414
Evidence that dietary lycopene decreases the risk for a number of health conditions has generated new opportunities for the addition of lycopene to functional foods. This work examined the potential of oil-in-water emulsions as a lycopene delivery system for foods. Oil-in-water emulsions containing lycopene were prepared using different kinds of surfactant (cationic, anionic, and nonionic) and oil types (corn oil, stripped corn oil, and hexadecane). The formation of fatty acid oxidation products and the degradation of lycopene and tocopherol were then monitored. Fatty acids and lycopene had greater stability in oil-in-water emulsions stabilized by cationic dodecyltrimethylammonium bromide (DTAB) or nonionic polyoxyethylene (23) lauryl ether than by anionic sodium dodecyl sulfate (SDS). Oxidative stability in the corn oil-in-water emulsions stabilized by SDS was in the following order: tocopherolhexadecane>tocopherol-stripped corn oil. Lycopene degradation rates were similar in emulsions with and without fatty acids, suggesting that lycopene loss was independent of the presence of fatty acids. These results suggest that the stability of lycopene in oil-in-water emulsions could be inhibited by altering the emulsion droplet interface and by the presence of tocopherols. 相似文献
87.
Carbohydrates in commercial tobacco products were quantified utilizing a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) technique. The method utilizes negative ion electrospray with multiple reactions monitoring and an internal standard calibration. Snuffs, chewing tobaccos, cigars, and cigarettes were analyzed. Product type differentiation was possible using the carbohydrate levels coupled with pH and moisture contents. The LC-MS/MS method was compared to a method utilizing ion chromatography with pulsed amperometric detection. The LC-MS/MS method provided improved selectivity and specificity, demonstrated better precision, and had a larger dynamic range for glucose, fructose, and sucrose in tobacco extracts. 相似文献
88.
Characterization of the cutaneous mycobiota in healthy and allergic cats using next generation sequencing
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89.
Halley E. Froehlich Jamie C. Montgomery David R. Williams Casey O'Hara Caitlin D. Kuempel Benjamin S. Halpern 《Fish and Fisheries》2023,24(6):1034-1047
Aquaculture (freshwater and marine) has largely supplemented fisheries, but in theory could help reduce fishing pressure on wild stocks. Although not the sole factors, some potential benefits depend on aquaculture pressures on fished species, including collection of wild ‘seed’ material—earlier to later life stages—for rearing in captivity and the capacity of aquaculture to increase. Here we first classify 203 marine (saltwater and brackish) animal species as being produced by either open-cycle capture-based aquaculture (CBA) or closed-cycle domesticated aquaculture (DA)—based on their likely reliance on wild seed—and assess the extent to which these forms of aquaculture could support seafood production and greater wild biomass. Using a data-limited modelling approach, we find evidence that current aquaculture practices are not necessarily helping reduce fishing to sustainable levels for their wild counterparts—consistent with emerging scientific research. However, if some wild capture species (87 equivalent spp.) were instead produced through CBA, almost a million extra tonnes could theoretically be left in the wild, without reducing seafood production. Alternatively, if reliance on wild seed inputs is further reduced by shifting to DA production, then a little less than doubling of aquaculture of the overexploited species in our study could help fill the ‘production gap’ to support fishing at maximum sustainable levels. While other ecological (e.g. escapes), social and economic considerations (e.g. market substitution) are important, we focused on a critical biological linkage between wild fisheries and aquaculture that provides another aspect on how to improve management alignment of the sectors. 相似文献