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排序方式: 共有196条查询结果,搜索用时 15 毫秒
51.
Morphologic observations on respiratory tracts of chickens after hatchery infectious bronchitis vaccination and formaldehyde fumigation 总被引:1,自引:0,他引:1
The histologic changes in the respiratory tracts of chickens were evaluated after hatchery fumigation with 40% formaldehyde vapors and vaccination against infectious bronchitis virus with live attenuated vaccine (Massachusetts serotype). One-day-old chickens were housed in four isolation units in controlled environmental conditions, fed and watered ad libitum, and separated into four groups: 1) fumigated and vaccinated birds (FV group); 2) nonfumigated and vaccinated birds (NFV group); 3) fumigated and nonvaccinated birds (FNV group); and 4) control group (C group). All birds were tested to be free from Mycoplasma gallisepticum and Mycoplasma synoviae. After necropsy on the first, eighth, and twenty-sixth days after birth, samples from tracheal upper portion and lungs were conventionally processed for light, scanning, and transmission electron microscopy. Tissue response was monitored by microscopic examination of trachea and lung. On the first day of observation, fumigated and vaccinated birds (FV group) showed extensively damaged tracheal epithelium with exfoliated areas and some active glands with electrodense granules, and in the lung, the primary bronchi epithelium had disorganized cilia and abundant lymphocytes, with emphysematous areas in tertiary bronchus. On day 8 after vaccination, cubical and cylindrical tracheal cell proliferation was observed, and on day 26, ciliated columnar epithelium was almost regenerated with heterophil corion infiltration, and hyaline cartilage nodules appeared in parabronchi. The nonfumigated and vaccinated birds (NFV) revealed less injury on the epithelial surface and a more rapid response to epithelial regeneration than the in only fumigated animals (FNV). The control group did not show remarkable morphologic changes. Postvaccinal and fumigation effects on the upper respiratory tract were temporary, whereas in lungs, increased emphysema, cartilage nodules in the interchange zone, and general lymphocyte infiltration had caused intensive injury. 相似文献
52.
53.
Application of Trichoderma harzianum (T22) and Trichoderma atroviride (P1) as plant growth promoters, and their compatibility with copper oxychloride 下载免费PDF全文
Francesco Vinale Gaetano D'' Ambrosio Khalid Abadi Felice Scala Roberta Marra David Turrà Sheridan L Woo Matteo Lorito 《浙江大学学报(农业与生命科学版)》2004,30(4):425-425
Trichoderma strains are used in agriculture because they provide to the plants the following benefits: i) are rhizosphere competence and establish stable rhizosphere microbial communities; ii) control plant disease caused by pathogenic and competitive microflora, by using a variety of mechanisms; iii) improve vegetative growth, root development and yield; iv) make nutrients more available to the plant. In this work we have investigated the ability of T. harzianum T22 and T. atroviride P… 相似文献
54.
Ericson LM Fan H Peng H Davis VA Zhou W Sulpizio J Wang Y Booker R Vavro J Guthy C Parra-Vasquez AN Kim MJ Ramesh S Saini RK Kittrell C Lavin G Schmidt H Adams WW Billups WE Pasquali M Hwang WF Hauge RH Fischer JE Smalley RE 《Science (New York, N.Y.)》2004,305(5689):1447-1450
Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties. 相似文献
55.
Ahn TK Avenson TJ Ballottari M Cheng YC Niyogi KK Bassi R Fleming GR 《Science (New York, N.Y.)》2008,320(5877):794-797
Energy-dependent quenching of excess absorbed light energy (qE) is a vital mechanism for regulating photosynthetic light harvesting in higher plants. All of the physiological characteristics of qE have been positively correlated with charge transfer between coupled chlorophyll and zeaxanthin molecules in the light-harvesting antenna of photosystem II (PSII). We found evidence for charge-transfer quenching in all three of the individual minor antenna complexes of PSII (CP29, CP26, and CP24), and we conclude that charge-transfer quenching in CP29 involves a delocalized state of an excitonically coupled chlorophyll dimer. We propose that reversible conformational changes in CP29 can "tune" the electronic coupling between the chlorophylls in this dimer, thereby modulating the energy of the chlorophyll-zeaxanthin charge-transfer state and switching on and off the charge-transfer quenching during qE. 相似文献
56.
Christin Selige Monike Quirino Filip Schröter Matteo Aepli Martin Schulze 《Reproduction in domestic animals》2021,56(8):1152-1155
Egg yolk (EY, control) is an essential ingredient of diluents for boar semen cryopreservation. Pasteurized egg yolk (PEY) reduces hygienic risks in processing and is easier to standardize. The aim of this study was to evaluate the in vitro effect of PEY (treatment) on frozen-thawed boar semen. In a split-sample approach (n = 13 boars), it could be shown that there is neither an influence (p > .05) on post-thawing motility (PTM: 5, 30 and 120 min) nor on morphologically intact sperm, percentage of acrosome defects and membrane fluidity using a PEY extender compared to the control. Mitochondrial activity (p = .043), membrane integrity (p = .015) and PTM 300 min (p = .023) were slightly affected in the treatment group. Overall, sperm quality was at a high level in both experimental groups. Further studies are needed to determine the impact of PEY on the fertilizing capacity of boar ejaculates. 相似文献
57.
Fast determination of catechins and xanthines in tea beverages by micellar electrokinetic chromatography 总被引:2,自引:0,他引:2
Bonoli M Colabufalo P Pelillo M Gallina Toschi T Lercker G 《Journal of agricultural and food chemistry》2003,51(5):1141-1147
Antioxidant properties and stimulating effects of green tea are related to its content of cathechins and xanthines; tea quality evaluation is based on organoleptic tests and on the presence of those components. In this work, by a MEKC method, eight cathechins and three xanthines were quantified in some tea-based beverages. The best separation was realized using a phosphate-borate running buffer, with sodium dodecyl sulfate as micellar agent. A 40 cm capillary, a temperature of 29 degrees C, a voltage of 30 kV, and UV detection at 200 nm were used. The method showed a very good sensitivity (limit of detection ranging from 0.0011 to 0.0051 microg/mL) and was applied to real tea samples to characterize their antioxidant content. Statistical studies were performed and showed a satisfactory reliability of the data. 相似文献
58.
John. W. Snape M. John Foulkes James Simmonds Michelle Leverington Lesley J Fish Yingkun Wang Matteo Ciavarrella 《Euphytica》2007,154(3):401-408
Crops frequently display genotype × environment interaction for yield and end-use quality in response to different environments,
particularly when stresses such as water limitation and temperature are components of the interaction. Plant breeders usually
exploit this variation via phenotypic selection to develop varieties with both general and specific adaptation. However the
individual genes and physiological processes underlying the basis of general and specific adaptation have rarely been elucidated.
We are combining large-scale QTL analysis of several doubled haploid populations of wheat, grown over different environments
and seasons, with detailed physiological analysis, to dissect the genes and mechanisms responsible for yield and yield × environment
variation in adapted European winter germplasm. Analysis of populations grown under irrigated and non-irrigated conditions
on drought-prone soils has revealed individual genes showing stable and differential expression over environments, and the
analysis has also identified physiological traits that contribute to differential yield performance. Genes on the homoeologous
group 2 chromosomes were associated with flag leaf senescence (stay-green) variation and were the most significant in drought
interactions. Variation for stem soluble carbohydrate reserves was associated with the 1RS arm of the 1BL/1RS translocated
chromosome, and was positively correlated with yield under both irrigated and non-irrigated conditions, and thus general adaptability.
Separate analyses of populations grown over three seasons in England, Scotland, France and Germany revealed QTL for yield
performance showing both general and specific effects. A stable QTL on chromosome 6A, consistent in different populations,
showed significant effects over seasons and environments, whilst other QTL were specific to season and/or environments. 相似文献
59.
60.
Brian Paterson David Mann Beverley Kelly & Matteo Barchiesi 《Aquaculture Research》2007,38(14):1569-1579
Limb‐loss in crustaceans can reduce moult increment and delay or advance the timing of moulting, both aspects that are likely to impact upon soft‐shell crab production. Pond‐reared blue swimmer crabs Portunus pelagicus were harvested and maintained in a crab shedding system. The wet weight, carapace width (CW) and the occurrence of limb‐loss were assessed before stocking in the shedding system and after each of the next three moults. Many of the crabs were initially missing one or two limbs and these did not grow as much as the crabs that were intact at the start of the trial. Despite its strong correlation with wet weight, CW changes proved to be misleading. Limb‐loss reduced the %CW increment but not the per cent weight increment (where the later is calculated from the actual pre‐moult weight). Pre‐moult weight explained much of the variation in post‐moult weight, with crabs moulting to approximately double their weight. Limb‐loss reduced ‘growth’ and production from the pond because it reduced pre‐moult weight but limb‐loss did not alter the weight change on shedding a given weight of crabs, although some of that change now included regeneration of limbs. One can hypothesize that much of the size variation seen in pond‐reared crabs may be due to accumulated effects of repeated limb‐loss, rather than genetic variation. 相似文献