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101.
Abstract AIM: To determine the effect of oral dosing of sheep with loline alkaloids on their excretion in urine and faeces, and to monitor for any toxic effects. METHODS: In Experiment 1, six 9-month-old ewe lambs were given a single oral dose of loline alkaloids (52 mg/kg bodyweight (BW); acute exposure) as a suspension of ground meadow fescue (Festuca pratensis) seed in water. In Experiment 2, on six consecutive days, six ewe lambs were given three doses of loline (68 mg/kg BW/day; chronic exposure). Blood was collected at variable intervals up to 72 h in Experiment 1, and up to 8 days in Experiment 2, for haematology and measurement of alkaline phosphatase, aspartate aminotransaminase, creatine kinase and γ-glutamyl transferase in plasma. Urine and faecal samples were collected at similar times for measurement of creatinine in urine and loline alkaloid analysis. A post mortem with histopathology was carried out on two animals at the end of each experiment. RESULTS: The loline alkaloids, N-acetyl norloline, N-formyl loline, N-acetyl loline, N-methyl loline and loline base were detected in urine within 15 minutes after the single dosing. N-formyl loline and loline base were the predominant metabolites in urine in both experiments. The total quantity of lolines excreted in both urine and faeces was 10% and 4% of the amount dosed in Experiments 1 and 2, respectively. In both experiments, the clinical chemistry parameters in blood and urine were within normal ranges. Post-mortem and histopathological examination did not show any abnormalities. CONCLUSIONS: This is the first report of loline alkaloid profiles in both urine and faeces of sheep. The appearance of loline alkaloids and the loline base in urine within 15 minutes suggests rapid uptake, metabolism and excretion. Loline alkaloids were non-toxic to sheep at the concentrations they are exposed to under New Zealand grazing conditions. The low recovery of loline alkaloids in urine and faeces in the absence of toxicity signs suggests lolines are extensively metabolised; probably to forms other than N-formyl loline, N-methyl loline, N-acetyl loline, N-acetyl norloline, and loline base in the digestive tract of sheep prior to absorption, and/or in the liver or other tissues following absorption. 相似文献
102.
William H. Romme Craig D. Allen John D. Bailey William L. Baker Brandon T. Bestelmeyer Peter M. Brown Karen S. Eisenhart M. Lisa Floyd David W. Huffman Brian F. Jacobs Richard F. Miller Esteban H. Muldavin Thomas W. Swetnam Robin J. Tausch Peter J. Weisberg 《Strength and Conditioning Journal》2009,62(3):203-222
Piñon–juniper is a major vegetation type in western North America. Effective management of these ecosystems has been hindered by inadequate understanding of 1) the variability in ecosystem structure and ecological processes that exists among the diverse combinations of piñons, junipers, and associated shrubs, herbs, and soil organisms; 2) the prehistoric and historic disturbance regimes; and 3) the mechanisms driving changes in vegetation structure and composition during the past 150 yr. This article summarizes what we know (and don't know) about three fundamentally different kinds of piñon–juniper vegetation. Persistent woodlands are found where local soils, climate, and disturbance regimes are favorable for piñon, juniper, or a mix of both; fires have always been infrequent in these woodlands. Piñon–juniper savannas are found where local soils and climate are suitable for both trees and grasses; it is logical that low-severity fires may have maintained low tree densities before disruption of fire regimes following Euro-American settlement, but information is insufficient to support any confident statements about historical disturbance regimes in these savannas. Wooded shrublands are found where local soils and climate support a shrub community, but trees can increase during moist climatic conditions and periods without disturbance and decrease during droughts and following disturbance. Dramatic increases in tree density have occurred in portions of all three types of piñon–juniper vegetation, although equally dramatic mortality events have also occurred in some areas. The potential mechanisms driving increases in tree density—such as recovery from past disturbance, natural range expansion, livestock grazing, fire exclusion, climatic variability, and CO2 fertilization—generally have not received enough empirical or experimental investigation to predict which is most important in any given location. The intent of this synthesis is 1) to provide a source of information for managers and policy makers; and 2) to stimulate researchers to address the most important unanswered questions. 相似文献
103.
miRNA and piRNA expression profiles of breeder cock testes detected by next‐generation sequencing
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SR Wu W Guo YL Li XC Ren XY Lei XY Li JH Yao XJ Yang 《Reproduction in domestic animals》2017,52(2):203-213
miRNAs are small non‐coding regulatory RNAs that play key roles in diverse biological processes. In this study, we used the Solexa sequencing technique to profile miRNAs in breeder cock testes to illustrate their functions. A total of 663 co‐expressed miRNAs and 3,180 co‐expressed piRNAs were detected in three libraries. Based on Mir‐X? miRNA qRT‐PCR, three miRNAs representing low, medium and high expression levels according to the sequencing results were selected randomly to validate the miRNAs' expression profiles. Results suggested that the miRNA expression profiles data could represent actual miRNA expression levels. Moreover, target genes prediction of the co‐expressed miRNAs and further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed, which revealed that some candidate miRNAs were involved in the regulation of the spermatogenesis process, spermatozoa function and testicular metabolism. In conclusion, we provided a useful resource for further elucidation of the miRNAs' regulatory role in spermatogenesis, contributing to a preliminary database for functional and molecular mechanistic studies in testicular metabolism, spermatogenesis and other testes functions. 相似文献
104.
105.
Shuping Zhang Floyd Wilson Lanny Pace 《Journal of veterinary diagnostic investigation》2006,18(2):221-224
An approximately 2-month-old, reproductively intact female Domestic Shorthair kitten was presented to the Mississippi Veterinary Research and Diagnostic Laboratory with a history of possible trauma to the left shoulder region while playing with children, and was found dead the following day. Marked swelling, with subcutaneous edema and hemorrhages, was observed in the left forelimb. Severe pleocellular, but largely suppurative cellulitis, fasciitis, and interstitial myositis with edema were observed microscopically in sections from the affected limb. Massive numbers of gram-positive diplococci also were observed. Other pathologic changes included moderate interstitial pneumonia, mild cholangitis, lymph node hemorrhage, gastrointestinal nematodiasis, mild enteritis, and mild interstitial nephritis. Bacteriologic culture identified Streptococcus pneumoniae as the causative agent, which was confirmed by polymerase chain reaction amplification of the pneumolysin gene from chromosomal DNA of the isolate. 相似文献
106.
J G Floyd R S Ott R M Weigel G M Zinn J E Hixon 《American journal of veterinary research》1989,50(9):1493-1495
Efficacy of a repositol formulation of melengestrol acetate (MGA) for inhibition of pregnancy was determined in one hundred 14- to 16-month-old beef heifers. Nonpregnant heifers were allocated on the basis of weight into 5 groups of 20 heifers each and were given 0, 30, 60, 90, or 120 mg of repositol MGA, SC, on day 0. Four bulls, determined to be satisfactory potential breeders, were pastured with the heifers from postinjection days (PID) 7 to 177. The day of gestation was estimated for each heifer by rectal palpation at PID 59, 91, 134, 177, and 225. Heifers not pregnant by PID 177 were assigned a day of conception of greater than 177. For heifers given 0, 30, 60, 90, and 120 mg of MGA, respectively, the percentage pregnant at PID 177 was 95, 95, 50, 15, and 15%, and the median day of estimated conception was PID 21, 87, 175, greater than 177, and greater than 177. Repositol MGA significantly (P less than 0.001) affected the distribution of conception times over all doses. Average daily gain (+/- SEM) for 178 days was 0.28 +/- 0.04 kg, 0.24 +/- 0.03 kg, 0.33 +/- 0.04 kg, 0.40 +/- 0.03 kg, and 0.35 +/- 0.03 kg for heifers given 0, 30, 60, 90, and 120 mg of MGA, respectively. Increased dose of repositol MGA was associated with increased average daily gain, but this effect was not apparent when days pregnant were taken into account. Repositol MGA was an effective contraceptive for pastured heifers and the duration of its effect was dose-dependent. 相似文献
107.
An enteric coronavirus infection of cats and its relationship to feline infectious peritonitis 总被引:14,自引:0,他引:14
N C Pedersen J F Boyle K Floyd A Fudge J Barker 《American journal of veterinary research》1981,42(3):368-377
An enteric coronavirus that is antigenically closely related to feline infectious peritonitis virus (FIPV) is ubiquitous in the cat population. This virus has been designated feline enteric coronavirus to differentiate it from FIPV. The virus is shed in the feces by many seropositive cats; in catteries it is a cause of inapparent to mildly severe enteritis in kittens 6 to 12 weeks of age. The virus may produce a more severe enteritis in young specific-pathogen-free kittens. Feline enteric coronavirus selectively infects the apical columnar epithelium of the intestinal villi, from the caudal part of the duodenum to the cecum. In severe infections, there are sloughing of the tips of the villi and villous atrophy. Many cats recovering from the disease remain carriers of the virus. Recovered cats, observed for 3 to 24 months, remained healthy and did not develop peritonitis, pleuritis, or granulomatous disease. The relationship of feline enteric coronavirus and FIPV was studied. Although the viruses were antigenically similar, they were distinctly different in their pathogenicities. The enteric coronavirus did not cause feline infectious peritonitis in coronavirus antibody-negative cats inoculated orally or intraperitoneally nor in coronavirus antibody-positive cats inoculated intraperitoneally or intratracheally. Serologic tests, using FIPV, canine coronavirus, and transmissible gastroenteritis virus of swine as substrate antigens in fluorescent antibody procedures may not accurately identify FIPV infection. These tests do not appear to distinguish between FIPV and this feline enteric coronavirus. 相似文献
108.
A simple heat transfer model is presented for estimating the diurnal variation in temperature of air, water and leaf surfaces. It is based on a sinusoidal heat input, modelling the influence of the sun, and a linear heat loss, modelling the cooling process. The model parameters were estimated by least squares fitting of average hourly temperatures. The predictions of the model were acceptable for all data sets resulting in root mean square values of 0.78°C or less. The use of the model in agricultural and biological modelling, as a method of fitting diurnal temperature curves in any media is discussed. 相似文献
109.
Sischo WM Floyd JG McKean JD Hueston WD 《Journal of the American Veterinary Medical Association》1999,215(10):1439-1443
OBJECTIVE: To assess veterinary extension in the United States as perceived by veterinary extension personnel. DESIGN: Cross-sectional survey. SAMPLE POPULATION: Extension veterinarians in the United States. PROCEDURE: 2 surveys were designed and mailed to extension veterinarians listed by the USDA and the American Association of Extension Veterinarians. RESULTS: 34 states had > or = 1 extension veterinarian. The majority (> 60%) of extension veterinarians did not commit time to resident education and were not involved in research activities. Paradoxically, 23% of responding extension veterinarians did not report extension work. Programs for food animal producers, horse owners, and companion animal owners were provided by 100, 63, and 37% of states, respectively. Continuing education (CE) programs were provided for food animal veterinarians, equine veterinarians, and companion animal veterinarians by 96, 63, and 52% of states, respectively. Challenges facing veterinary extension included limited recognition of veterinary extension activities by universities, lack of university personnel to support CE programs, and decreased support for companion animal extension programs. CONCLUSIONS AND CLINICAL RELEVANCE: Extension veterinarians need to identify and clearly articulate the mission of veterinary extension, develop more collaborative programs across regions, and continue to serve as catalysts to bring diverse constituents together. Extension veterinarians must distinguish their mission not solely as information transfer, which can be accomplished in a variety of ways outside of extension, but as a coherent and consistent program of education and policy developed on a national level and distributed locally. 相似文献
110.