全文获取类型
收费全文 | 396篇 |
免费 | 44篇 |
国内免费 | 1篇 |
专业分类
林业 | 14篇 |
农学 | 4篇 |
基础科学 | 2篇 |
31篇 | |
综合类 | 71篇 |
农作物 | 8篇 |
水产渔业 | 19篇 |
畜牧兽医 | 249篇 |
园艺 | 14篇 |
植物保护 | 29篇 |
出版年
2023年 | 5篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 29篇 |
2012年 | 17篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 7篇 |
2007年 | 11篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 11篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 8篇 |
1970年 | 4篇 |
1968年 | 4篇 |
1966年 | 5篇 |
1965年 | 2篇 |
1945年 | 4篇 |
1925年 | 2篇 |
排序方式: 共有441条查询结果,搜索用时 15 毫秒
71.
B.J. Mansell MS L.A. Baker PhD J.L. Pipkin PhD G.D. Potter PhD R.C. Bachman MS L.J. Perino PhD DVM G.O. Veneklasen DVM J.C. Haliburton PhD DVM M.A. Buchholz-Bryant MS 《Journal of Equine Veterinary Science》2001,21(9)
An experiment was performed to determine the effects of Ca and P supplementation, inactivity, and subsequent aerobic exercise on bone metabolism in young, mature, and aged horses. Twelve stock-type geldings were blocked into three groups: 2 and 3, 7 to 11, and 15 to 21 years of age. Horses within age groups were evenly divided and randomly assigned to one of two dietary treatments; control (C) or Ca and P supplementation (T). Horses consuming C and T received about 133% and 275% of National Research Council (NRC) requirements for Ca and P, respectively. The trial consisted of eight 21-day periods. During periods I, II, and III, all horses were inactive and received no forced exercise. During periods IV, V, VI, VII, and VIII, all horses were placed on an ascending aerobic exercise regimen. Blood samples were taken at the beginning of period I and at 21-day intervals thereafter to determine serum concentrations of osteocalcin (OST) and type I carboxyterminal telopeptide (ICTP). Dorsal-palmar and lateral-medial radiographs were taken of the left third metacarpal at the beginning of period I and at 21-day intervals thereafter to monitor changes in bone densities, as indicated by radiographic bone aluminum equivalencies (RBAE). Mean serum OST was affected by age (P < .004) and the interaction of time and age (P < .006). Mean serum ICTP was affected by age (P < .001), time (P < .001), the interaction of time and age (P < .001); and the interaction of time and treatment (P < .05). There was an effect of treatment on overall mean medial (MRBAE; P < .04) and total (TRBAE; P < .04) RBAE. Overall mean dorsal RBAE (DRBAE; P < .001), palmar RBAE (PRBAE; P < .003), lateral RBAE (LRBAE; P < .001), MRBAE (P < .001), normalized MRBAE (P < .001), TRBAE (P < .05), and normalized TRBAE (P < .05) were affected by time. There was an effect of the interaction of time and age on overall mean DRBAE (P < .05), LRBAE (P < .002), MRBAE (P < .02), normalized MRBAE (P < .02), TRBAE (P < .005), and normalized TRBAE (P < .005). Overall mean DRBAE (P < .02) and PRBAE (P < .001) were affected by the interaction of time, treatment, and age. Biochemical and radiographic data from this experiment indicate that dietary Ca and P supplementation may affect bone remodeling in aerobically exercised horses of varying ages following a period of inactivity. Furthermore, the data indicate that bone in horses of varying ages responds differently to inactivity and exercise. 相似文献
72.
Genetically engineered (GE) animals are likely to have an important role in the future in meeting the food demand of a burgeoning global population. There have already been many notable achievements using this technology in livestock, poultry and aquatic species. In particular, the use of RNA interference (RNAi) to produce virus‐resistant animals is a rapidly‐developing area of research. However, despite the promise of this technology, very few GE animals have been commercialised. This review aims to provide information so that veterinarians and animal health scientists are better able to participate in the debate on GE animals. 相似文献
73.
74.
75.
John Potter 《New Zealand veterinary journal》2013,61(7)
Abstract Extract Madam:— The N.Z.V.A. Nominee on the National Hydatids Council, Mr Peter Malone, in his annual report states that he knows of “no professional concerns that would allow certificates to be issued to exempt dogs from dosing with droncit, and on receipt of copies of such certificates will continue to forward them to the Veterinary Council to examine for disciplinary action”. (1 In September 1985 I examined a nine year old miniature poodle dog that had been dosed with droncit by a hydatids control officer two hours previously. The dog had collapsed into lateral recumbancy, was pale and cyanotic with a rectal temperature of 37.3°C. Cardiac and thoracic auscultation was normal, and no other abnormal clinical signs were detected. There was no previous history of similar episodes and the dog has been dosed with droncit several times beforehand without problems. The dog was treated with betamethasone and millophylline and made a full recovery within 48 hours. 相似文献
76.
Abstract Extract The paper by Goodwin et al (2004) which appeared in the August 2004 issue of the New Zealand Veterinary Journal highlighted the prevalence and costs to the sheep industry of pneumonia in lambs. The costs are considerable, and the article begs the question, “what can sheep farmers do to reduce the effects of pneumonia in lambs?” 相似文献
77.
78.
79.
B.D. Nielsen PhD G.D. Potter PhD L.W. Greene PhD E.L. Morris DVM M. Murray-Gerzik MS W.B. Smith PhD M.T. Martin DVM 《Journal of Equine Veterinary Science》1998,18(3):190-200
This study was conducted to determine physiologic responses reflective of bone metabolism during the onset of training and to relate those responses to the mineral requirements of young racehorses. Ten previously untrained Quarter Horse geldings were put into race training. They were fed a diet balanced to meet NRC recommendations for young horses in training. Feed, feces and urine were collected, weighed and analyzed over the experiment to determine mineral balance. Radiographs were taken of the left front leg to determine mineral content of a cross-sectional area of the third metacarpal. Blood samples were taken to determine osteocalcin, parathyroid hormone, 25-hydroxyvitamin D, Ca and inorganic P concentrations. Horses were gentled to ride, trained to gallop on the track and maintained in training for four 28-day periods. Blood serum was collected every 14 day, while radiographs and 72-hr total collections of urine and feces were taken every 28 d. Radiographs demonstrated that mineral content was lowest at day 56 in the dorsal, palmar and medial cortices of the third metacarpal. Urinary Ca declined dramatically from day 0 to day 28, then remained constant to day 56, before decreasing at day 84. Fecal Ca peaked at day 28 and remained elevated above day 0 amounts until day 112. calcium retention was negative at day 0, became slightly positive by day 28 and increased through day 112. Phosphorus and Mg balance remained relatively unchanged throughout the duration of the study. This study demon-strated changes in the mineral content of the third metacarpal and Ca balance during early training and suggests that further studies be performed. 相似文献
80.
Pathogenesis of porcine Actinobacillus pleuropneumonia, part II: roles of proinflammatory cytokines. 下载免费PDF全文
H Huang A A Potter M Campos F A Leighton P J Willson D M Haines W D Yates 《Canadian journal of veterinary research》1999,63(1):69-78
The in vitro production of proinflammatory cytokines after stimulation with Actinobacillus pleuropneumoniae and the relation of these cytokines in vivo with the disease caused by A. pleuropneumoniae were investigated. Within 24 h, in vitro stimulation by A. pleuropneumoniae (serotype 1) preparations, including killed bacteria, bacterial culture supernatant, lipopolysaccharide, and bacterial extracts, porcine pulmonary alveolar macrophages (PAM) produced significant (P < 0.05) amounts of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) as measured by bioassays. The supernatants containing interleukin-8 from PAM after stimulation by bacterial preparations showed significant neutrophil chemotaxis, while bacterial preparations alone did not. After in vivo infection with A. pleuropneumoniae, the mean levels of TNF-alpha and IL-1 in serum, as measured by bioassays, were elevated 37- to 27836-fold for TNF-alpha and 11- to 5941-fold higher for IL-1 within 4 d post-infection, depending on the treatments, and remained elevated up to Day 7. Both cytokines were also detected in porcine lungs by bioassays and immunocytochemistry. The results indicated that both secreted and surface components of A. pleuropneumoniae can stimulate PAM to produce proinflammatory mediators. Neutrophil chemoattractants rather than bacterial components are the major factor causing acute lung inflammation. The elevation of TNF-alpha and IL-1 in pigs occurred coincident with the onset of acute clinical disease. 相似文献