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排序方式: 共有469条查询结果,搜索用时 31 毫秒
31.
Respiratory function and pulmonary lesions in pigs infected with porcine reproductive and respiratory syndrome virus 总被引:1,自引:0,他引:1
Judith Wagner Annette Kneucker Elisabeth Liebler-Tenorio Vicky Fachinger Melanie Glaser Stefan Pesch Michael P. Murtaugh Petra Reinhold 《Veterinary journal (London, England : 1997)》2011,187(3):310-319
Pulmonary dysfunction was evaluated in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV, isolate VR-2332) and compared to clinical and pathological findings. Infected pigs developed fever, reduced appetite, respiratory distress and dullness at 9 days post-inoculation (dpi). Non-invasive pulmonary function tests using impulse oscillometry and rebreathing of test gases (He, CO) revealed peripheral airway obstruction, reduced lung compliance and reduced lung CO-transfer factor. PRRSV-induced pulmonary dysfunction was most marked at 9–18 dpi and was accompanied by a significantly increased respiratory rate and decreased tidal volume. Expiration was affected more than inspiration. On histopathological examination, multifocal areas of interstitial pneumonia (more severe and extensive at 10 dpi than 21 dpi) were identified as a possible structural basis for reduced lung compliance and gas exchange disturbances. 相似文献
32.
Els M. Broens Elisabeth A.M. Graat Peter J. Van Der Wolf Arjen W. Van De Giessen Mart C.M. De Jong 《Veterinary journal (London, England : 1997)》2011,189(3):302-305
The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs at abattoirs is higher than in pigs sampled on farms. This study investigated whether MRSA negative pigs can become MRSA positive during transportation from the farm to the abattoir after exposure to other pigs and environmental sources of MRSA. Nasal swabs were collected from four batches of pigs during loading at the farm, on arrival at the abattoir and after stunning. Environmental wipes were taken from lorries after transporting pigs and from lairages after holding pigs. All pigs (n = 117) tested MRSA negative before transportation. On arrival at the abattoir, 12/117 (10.3%) pigs in two batches tested MRSA positive. In lorries that tested positive after transportation, the prevalence of MRSA positive pigs was 21.1%, whereas no MRSA was detected in pigs that had been transported in lorries that tested negative after transportation. At stunning, all batches and 70/117 (59.8%) pigs tested MRSA positive. Pigs can become MRSA positive in the short period of time during transportation from the farm to stunning at the abattoir. 相似文献
33.
Mohamed EL‐SHEHABY Mohamed Sayed SALAMA Elisabeth BRUNNER Jürgen HEINZE 《Integrative zoology》2011,6(3):259-265
Discrimination between nestmates and non‐nestmates in social insects is thought to rely on the pattern of cuticular hydrocarbons. We investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species, Temnothorax nylanderi (Förster, 1850) and Temnothorax crassispinus (Karavaiev, 1926), and their hybrid. We found that although the profiles show considerable similarities, a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 taxa. The profiles of hybrids were not consistently intermediate between those of the paternal species, suggesting either non‐additive interactions among the parental biosynthetic pathways or systematic differences in environment‐derived odor cues. 相似文献
34.
Walker AS Gautier AL Confais J Martinho D Viaud M Le P Cheur P Dupont J Fournier E 《Phytopathology》2011,101(12):1433-1445
Botrytis cinerea is a major crop pathogen infesting >220 hosts worldwide. A cryptic species has been identified in some French populations but the new species, B. pseudocinerea, has not been fully delimited and established. The aim of this study was to distinguish between the two species, using phylogenetic, biological, morphological, and ecological criteria. Multiple gene genealogies confirmed that the two species belonged to different, well-supported phylogenetic clades. None of the morphological criteria tested (spore size, germination rate, or mycelial growth) was able to discriminate between these two species. Sexual crosses between individuals from the same species and different species were carried out. Only crosses between individuals from the same species were successful. Moreover, population genetics analysis revealed a high level of diversity within each species and a lack of gene flow between them. Finally, a population survey over time showed that B. cinerea was the predominant species but that B. pseudocinerea was more abundant in spring, on floral debris. This observation could not be explained by temperature adaptation in tests carried out in vitro or by aggressiveness on tomato or bean leaves. This study clearly establishes that B. cinerea and B. pseudocinerea constitute a complex of two cryptic species living in sympatry on several hosts, including grapevine and blackberry. We propose several biological or molecular tools for unambiguous differentiation between the two species. B. pseudocinerea probably makes a negligible contribution to gray mold epidemics on grapevine. This new species has been deposited in the MycoBank international database. 相似文献
35.
Creaming in black tea 总被引:1,自引:0,他引:1
Jöbstl E Fairclough JP Davies AP Williamson MP 《Journal of agricultural and food chemistry》2005,53(20):7997-8002
Tea cream is the precipitate formed as tea cools. Its formation has been studied by X-ray scattering, and it is shown that a higher tea concentration leads to earlier onset of creaming and larger particles and that addition of theaflavin and calcium promotes creaming. Association constants between the major components of black tea have been obtained using NMR and show that calcium and glucose enhance the self-association of caffeine, polyphenols, and theaflavin but have little effect on hetero-association. Glycosylation of a polyphenol reduced self-association and reduced binding to caffeine. We conclude that theaflavin is important for the initiation of creaming, forming nanoclusters of typically 3 nm diameter, whereas caffeine acts more to fill in the gaps within the clusters and thus adds to the bulk of tea cream without being necessary for its initiation. Tea creaming may be reduced by increasing the solubility of the polyphenols (i.e., by glycosylation) or by removing calcium. Tea cream; theaflavin; caffeine; small-angle X-ray scattering; NMR; colloid. 相似文献
36.
Elisabeth Hornung Ferenc Vilisics Andrs Tartally 《European Journal of Soil Biology》2005,41(3-4):129-133
The myrmecophilous Platyarthrus schoblii Budde-Lund, 1885 is widely distributed and native in the Mediterranean region. In Hungary it was first found at Budapest, in 2001, in a colony of Lasius neglectus van Loon, Boomsma and Andrásfalvy, 1990 (Hymenoptera: Formicidae). This invasive and polygynous ant species is dispersing in an antropochorous way throughout Europe. There are 16 known colonies of L. neglectus in Hungary. Fourteen of them have been surveyed for the isopod, which was detected in eight cases (57%). In addition to L. neglectus, the isopod has been recently found with other native ant species [Lasius niger (Linnaeus, 1758), Lasius emarginatus (Olivier, 1791) and Tetramorium caespitum (Linnaeus, 1758)] in the country. We have also found the joint occurrence of P. hoffmannseggii Brandt, 1833 and P. schoblii. The co-occurrence and joint expansion of the ranges of L. neglectus and P. schoblii indicates their co-habitation and antropochorous dispersal while the appearance with L. emarginatus, L. niger and T. caespitum supports our hypothesis about possible adoption by different ant species. 相似文献
37.
Significance of microbial biomass and non-exchangeable ammonium with respect to the nitrogen transformations in loess soils of Niedersachsen during the growing season of winter wheat. I. Change of pool sizes Nitrogen transformations in loess soils have been examined by laboratory and field experiments. After straw application (· 8 t · ha?1), N in microbial biomass (Nmic) increased by about 20 mg · kg?1 soil (· 90 kg N · ha?1 · 30 cm?1) after 9 days of incubation (20 °C). Another laboratory experiment yielded an increase of about 400 mg of NH4+-N · kg?1 fixed by minerals within 1 h after addition of 1 M NH4+-acetate. Defixation of the recently fixed NH4+ after addition of 1 M KCl amounted to only 60 mg · kg?1 within 50 days. In a field experiment with winter wheat 1991, an increase in Nmic of about 80 kg N · ha?1 · 30 cm?1 was observed from March to June. After July, growth of the microbes was limited by decreased soluble carbon concentrations in the rhizosphere. Different levels of mineral N-fertilizer (0, 177 and 213 kg N · ha?1) did not affect significantly the microbial biomass. The same field experiment yielded a decrease of non-exchangeable ammonium on the “zero”-fertilized plot in spring by 200 kg N · ha?1 · 30 cm?1. The pool of fixed ammonium increased significantly after harvest. After conventional mineral N-fertilizer application (213 kg N · ha?1). NH4+-defixation was only about 120 kg N · ha?1 · 30 cm?1 until July. 相似文献
38.
39.
Die Dauer der biologischen Rastzeit ist eine variable Grβe und wird von ver-schiedenen endogenen und exogenen Faktoren beeinfluβt. Eine Rastzeit unter 60 Ta-gen ist nur bei einem kleinen Prozentsatz der Tiere als biologisch anzusehen. Eine indi-viduelle durchschnittliche Zwischenkalbezeit von 341 bis 360 Tagen ist in der Landes-zucht trotz frühzeitiger Besamung post partum nur bei einem relativ kleinen Prozentsatz zu erreichen (16,5 %). Eine individuelle durchschnittliche Zwischenkalbezeit von 361 Bis 380 Tagen dürfte als Ausdruck guter Fruchtbarkeit bei den heutigen Fütte-rungs- und Haltungsbedingungen zu werten sein. Bei einer individuellen durchschnitt-lichen Zwischenkalbezeit von 381 bis 400 Tagen liegt der Verdacht vor, daβ Fütte-rungs- und Haltungsfehler sowie Geburts- und Puerperalstörungen die Ursache der ver-langerten Zwischenkalbezeit sind. Bei Kühen mit einer sehr hohen Milchleistung kann diese Zwischenkalbezeit noch als vertretbar angesehen werden. Tiere mit einer individuellen durchschnittlichen Zwischenkalbezeit von über 400 Tagen sind im allgemeinen ats Minusvarianten hinsichtlich Fruchtbarkeit einzustufen. Dies gilt allerdings nicht für Tiere mit einer weit über dem Herdendurchschnitt liegenden Milchleistung. Eine Ver-kurzung der individuellen durchschnittlichen Zwischenkalbezeit erscheint möglich durch: Verbesserung von Fütterung und Haltung; gutes Management; Fruchtbarkeits-uberwachung; Verbesserung der Geburtshygiene; tierärztliche Überwachung von Puer-perium und Gustreit; Prophylaxe und rechtzeitige Behandlung diagnostizierter Erkran-kungen . 相似文献
40.