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B. AUSTIN M. STOBIE P. A. W. ROBERTSON H. G. GLASS J. R. STARK M. MUDARRIS 《Journal of fish diseases》1993,16(3):277-280
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1. Spermatozoa in semen samples from 8 individual male domestic fowls were shown to have a differential and characteristic ability to hydrolyse holes in the inner perivitelline layer from laid eggs in an in vitro assay. 2. The number of holes produced by samples of spermatozoa per unit area of inner perivitelline layer in vitro was linearly correlated with sperm ATP content ( r = 0.85) and motility (r=0.76). 3. The number of holes formed in the inner perivitelline layer in vitro was also linearly correlated with the numbers of holes formed in the inner perivitelline layer of eggs fertilised in vivo , in inseminated hens (r=0.90); and was correlated logarithmically with the proportion of fertile eggs laid by these hens. 相似文献
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Plants of Ulex europaeus were grown from cuttings and studies made of the absorption of 14C-picloram applied with unlabelled 2,4,5-T. In vivo experiments in a growth chamber showed that absorption ceased after 10 h, but was resumed on wetting. In in vitro experiments the Q10 and the activation energy for uptake decreased with increasing temperature. Absorption was increased by addition of non-ionic surfactants, by lowering the pH and by removal of cuticular wax. Gorse shoots were shown to have a high wax content but scanning electron microscopy revealed no obvious wax structures and the contact angle of spray droplets was less than 900, indicating that the surfaces were not difficult to wet. 相似文献
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Abstract. Sections of the bottom of three earthen fish ponds in central Scotland were enclosed to prevent access by juvenile brown trout, Salmo trutta L., stocked at different densities from July to October. Monthly benthic samples were taken inside and outside the enclosures with a suction sampler. The benthos was dominated by Oligochaeta, whose density and biomass were significantly lower outside the enclosures; production was also lower outside but the P:B ratio was much higher. Total Chironomidae were more abundant outside, but not the larger predatory species which appeared to control the inside population. Species diversity of Oligochaeta and Chironomidae was greater outside while mean size was reduced, presumably as a result of size-selective predation by trout. Numbers of Mollusca and Asellidae were lower in the presence of fish, but Hirudinea and Sialidae were unaffected. Increasing fish density boosted chironomid numbers and biomass, indicating a predominant response to organic enrichment, but reduced the numbers of most other benthic groups presumably as a result of predation. 相似文献
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This series of papers examines some significant differences in the constitution of organic matter found amongst major soil groups and their genetic and morphological horizons, as determined by the dynamic pyrolysis-mass spectrometry of whole soil samples. Multivariate methods of data analysis identify groups of co-variant mass ions which successfully partition samples in terms of the above soil categories, and correlate with other major properties such as humification and hydromorphism. This first study covers the A horizons from a group of 22 Scottish soils chosen from the major temperate soil groups including brown forest soils, podzols, and noncalcareous, peaty and humic gleys (phaeozems, cambisols, podzols and gleysols). The principal components analysis of 52 mass ion intensities was found to partition the soils successfully in terms of two main factors which represented 62% of the total statistical variance. The first factor was found to correspond closely to the extent of hydromorphism, being high for highly gleyed A horizons, and depended chiefly on the presence of aromatic hydrocarbon ions. The second factor corresponded to the extent of mull humus formation, being high for brown forest soils (phaeozems, cambisols) and low for podzols, and depended chiefly on the abundance of polypeptide products relative to polysaccharide products. This second factor was evidently a more comprehensive expression of a humification factor found in previous studies. The relationships of these factors with C and N content and with base status properties were examined. 相似文献
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MILA FREIRE IAN ROBERTSON HOWARD D. BONDELL JAMES BROWN JON HASH ANTHONY P. PEASE B. DUNCAN X. LASCELLES 《Veterinary radiology & ultrasound》2011,52(3):239-247
Degenerative joint disease (DJD) is common in domesticated cats. Our purpose was to describe how radiographic findings thought to indicate feline DJD relate to macroscopic cartilage degeneration in appendicular joints. Thirty adult cats euthanized for reasons unrelated to this study were evaluated. Orthogonal digital radiographs of the elbow, tarsus, stifle, and coxofemoral joints were evaluated for the presence of DJD. The same joints were dissected for visual inspection of changes indicative of DJD and macroscopic cartilage damage was graded using a Total Cartilage Damage Score. When considering all joints, there was statistically significant fair correlation between cartilage damage and the presence of osteophytes and joint‐associated mineralizations, and the subjective radiographic DJD score. Most correlations were statistically significant when looking at the different joints individually, but only the correlation between the presence of osteophytes and the subjective radiographic DJD score with the presence of cartilage damage in the elbow and coxofemoral joints had a value above 0.4 (moderate correlation). The joints most likely to have cartilage damage without radiographic evidence of DJD are the stifle (71% of radiographically normal joints) followed by the coxofemoral joint (57%), elbow (57%), and tarsal joint (46%). Our data support radiographic findings not relating well to cartilage degeneration, and that other modalities should be evaluated to aid in making a diagnosis of feline DJD. 相似文献