全文获取类型
| 收费全文 | 70篇 |
| 免费 | 3篇 |
专业分类
| 林业 | 7篇 |
| 农学 | 1篇 |
| 3篇 | |
| 综合类 | 1篇 |
| 农作物 | 4篇 |
| 水产渔业 | 2篇 |
| 畜牧兽医 | 48篇 |
| 园艺 | 3篇 |
| 植物保护 | 4篇 |
出版年
| 2022年 | 1篇 |
| 2021年 | 3篇 |
| 2020年 | 2篇 |
| 2019年 | 3篇 |
| 2018年 | 1篇 |
| 2017年 | 1篇 |
| 2016年 | 5篇 |
| 2015年 | 1篇 |
| 2014年 | 2篇 |
| 2013年 | 2篇 |
| 2012年 | 1篇 |
| 2011年 | 6篇 |
| 2010年 | 2篇 |
| 2009年 | 2篇 |
| 2008年 | 6篇 |
| 2007年 | 5篇 |
| 2006年 | 5篇 |
| 2005年 | 2篇 |
| 2004年 | 5篇 |
| 2003年 | 3篇 |
| 2002年 | 1篇 |
| 2000年 | 1篇 |
| 1999年 | 2篇 |
| 1997年 | 3篇 |
| 1996年 | 1篇 |
| 1995年 | 1篇 |
| 1994年 | 1篇 |
| 1993年 | 1篇 |
| 1992年 | 1篇 |
| 1990年 | 1篇 |
| 1986年 | 1篇 |
| 1984年 | 1篇 |
排序方式： 共有73条查询结果，搜索用时 31 毫秒
1.
The aim of the present study was to examine whether cumulus and fibroblast cell nuclear-transferred oocytes, which have high and low potential to develop into normal calves, respectively, are different in terms of in their patterns of timing of first cleavage and in their relationships between timing of first cleavage and in vitro developmental potential. The timing of first cleavage was similar in both types of nuclear-transferred and in vitro fertilized oocytes. More than 86% of the oocytes cleaved within 24 h after activation or in vitro fertilization; these oocytes contributed to more than 98% of the total number of blastocysts in all three groups. The potential of oocytes that cleaved at different intervals to develop into blastocysts differed among the groups. The developmental potential of the cumulus cell nuclear-transferred oocytes and in vitro fertilized oocytes decreased with the increase in time required for cleavage. Fibroblast cell nuclear-transferred oocytes that cleaved at 20 h, an intermediate cleaving time, had higher potential to develop into blastocysts. The results of the present study suggest that the type of donor nucleus used for nuclear transfer affects the timing of first cleavage. 相似文献
2.
Ether and methanol extracts of Ixora coccinea dry leaves were tested for their antimicrobial activity. Ether fraction was found to be more active than the methanol fraction. 相似文献
3.
The effects of high dose of microbial phytase and an emulsifier on the performance, apparent metabolisable energy (AME) and nitrogen (N) retention in broilers fed on diets containing different fat sources were examined in a 5-week trial. Two fat sources (soy oil and tallow), two inclusion levels of E. coli phytase (500 or 1000 phytase units (FTU)/kg diet) and two inclusion levels of lysolecithin emulsifier (0 or 3.5 g/kg of diet) were evaluated in a 2 × 2 × 2 factorial arrangement of treatments.
Throughout the 5-week trial, soy oil supplementation improved weight gain and feed per gain compared with tallow, but had no effect on feed intake.
The high dose of phytase increased the weight gain and feed intake and lowered the feed per gain during d 1–21, but had no effect on performance parameters over the whole trial period.
An effect of emulsifier was observed for feed intake during d 1–21 and over the whole trial period. Addition of emulsifier increased feed intake compared with diets without emulsifier.
During weeks 1, 2, 3 and 5, birds fed on soy oil–based diets had higher nitrogen-corrected AME (AMEN) compared with those fed on tallow-based diets. During weeks 2, 3 and 5, the effect of phytase was significant for AMEN, with the high dose increasing the AMEN. During week 2, AMEN was increased with emulsifier addition.
During weeks 1, 2, 3 and 5, birds fed on soy oil–based diets had higher fat retention compared with those fed on tallow-based diets. The high dose of phytase improved the retention of fat during week 5 and the addition of emulsifier resulted in higher fat retention during week 1.
During weeks 2, 3 and 5, an interaction between fat source × phytase × emulsifier was observed for N retention. In soy oil–based diets, emulsifier plus 1000 FTU/kg phytase increased N retention compared with other groups, while in tallow-based diets, emulsifier addition increased N retention in diets with 500 FTU/kg, but not in 1000 FTU/kg diet.
Overall, the present data suggest that the dietary fat source influenced performance, AMEN and fat retention in broiler chickens. There is opportunity to improve bird performance during d 1–21, AMEN and fat retention with higher doses of microbial phytase. Addition of the emulsifier increased the AMEN during week 2 and tract retention of fat during week 1, but this effect was not translated into improvements in performance.
4.
Zainal Abidin Cik Mohd Rizuan Mohd Noor Hafidzi Hamid Noor Hisham Ravindran Shakinah Puan Chong Leong Kasim Azhar Salim Hasber 《Journal of pest science》2022,95(2):1009-1022
Journal of Pest Science - In Peninsular Malaysia, barn owls (Tyto javanica javanica) have been utilized as biological control of rats since the 1960s. In this study, the impact of introduced barn... 相似文献
5.
Angkanaporn K. Ravindran V. Mollah Y. Bryden W.L. 《Veterinary research communications》1997,21(3):161-167
Angkanaporn, K., Ravindran, V., Mollah, Y. and Bryden, W.L., 1997. Secretion of homoarginine into the gut of chickens. Veterinary Research Communications, 21(3), 161-167A technique, based on the homoarginine present in guanidinated proteins, has been used to distinguish between endogenous secretions and exogenous dietary amino acids in the ileal digesta of monogastric animals. This technique assumes that the ingested homoarginine is not recycled into the small intestine after absorption, but this assumption is yet to be experimentally validated in chickens. The secretion of homoarginine into the gut of broilers that were intravenously infused with 20 and 40 mmol/L homoarginine solutions was assessed. The plasma concentrations of homoarginine increased with increasing concentrations of homoarginine infused. However, only negligible levels of homoarginine (7.0 to 45.2 µg/g dry matter) were found in the digesta. Less than 0.01% of the intravenously infused homoarginine was recovered in the intestinal digesta, indicating that the secretion of homoarginine into the gut of chickens was insignificant. 相似文献
6.
A field experiment was conducted from 1985–1986 to 2002–2003 on Vertisols under rainfed conditions to evaluate the effect of cropping systems and application of fertilizers and manure on seed cotton yield. To determine the long‐term effects, trends and stability analyses were performed. Soil samples (0–0.15 and 0.15–0.30 m) were collected at the end of year 18 and analysed for available P and AB‐DTPA extractable Zn. Among cropping systems, Asiatic diploid cotton (Gossypium arboreum) yielded 233 kg ha?1 more seed cotton than the upland tetraploid cotton (Gossypium hirsutum). Yield trend was positive for G. arboreum compared with G. hirsutum. However, the slope was not significant. Stability analyses indicated overall higher yield stability for G. arboreum than G. hirsutum. Compared with monocropping G. hirsutum, G. hirsutum–sorghum (Sorghum bicolor L.) (H‐S) rotation was significantly more stable. Soil samples (0–0.30 m) of the manure‐amended plots had significantly greater P and Zn content (above the critical limit) compared to those receiving inorganic fertilizers alone. With regard to nutrient management practices, seed cotton yield was the highest for the integrated nutrient management (INM) treatment receiving a combination of organic and inorganic fertilizers. Among primary nutrients, the effect of P was significant while that of K was not. Balanced fertilizer application was significantly better than treatments receiving N and NK. Yield trends were, in general, not significant. However, a positive trend was noticed for treatments receiving manure compared to fertilizer alone. Stability analysis, on the other hand, indicated that the slopes were, in general, significant. Among the nutrients, mean yield response with and without P was 1007 and 672 kg ha?1 respectively. Combined application of manure and fertilizer (INM) resulted in the highest mean yield response (1218 kg ha?1) and the slope was highly significant (P < 0.004). In the manure‐amended plots, a better nutrient status probably imparted a greater degree of yield stability. The present study suggests that compared to trend analysis, stability analysis being sensitive as it recognizes the treatment × environment interaction, is a better option to interpret results from long‐term agronomic experiments. 相似文献
7.
Usually saline soils were reclamized by chemical or mechanical remediation, since the cost of leaching technique for saline soil reclamation is higher in India. In the present study an attempt has been made to investigate to identify the fast and luxuriantly growing halophytic herbs which are salt accumulators and to assess the feasibility of salt bioaccumulation. From the results it is concluded that among six species studied Suaeda maritima and Sesuvium portulacastrum exhibited greater accumulation of salts in their tissues as well as higher reduction of salts in the soil medium. 相似文献
8.
Thomas DG Ravindran V Thomas DV Camden BJ Cottam YH Morel PC Cook CJ 《New Zealand veterinary journal》2004,52(2):76-81
AIM: To compare the effects of four stocking densities (5, 10, 15 or 20 birds per m2) on the performance, carcass characteristics and selected welfare indicators of broiler chickens. METHODS: A total of 756 day-old male broiler chicks were assigned as six replicates of 13, 25, 38 and 50 birds per pen, to stocking densities of 2,000, 1,000, 667 and 500 cm2 floor space per bird, respectively. The birds were housed in floor pens in an environmentally controlled room. Normal commercial diets were fed ad libitum and fresh water was freely available throughout the 5-week study period. Liveweights of birds and feed intake were recorded at weekly intervals. Data on carcass parameters and welfare indicators (moisture, gait scores, feather scores, breast and hip lesions, and foot pad and hock burns) were obtained on Day 35. Adrenal glands were removed at slaughter, weighed and examined histologically to determine the total proportion of cortical and medullary tissues. RESULTS: During the study, the birds at the lowest density grew faster (p<0.001-0.01) and consumed more (p<0.001- 0.01) feed than those at the other three stocking densities. The liveweight gains and feed intake of birds reared at densities of 10, 15 and 20 birds per m2 were similar (p=0.11-0.83 and p=0.17-0.57, respectively). Stocking density had no influence on the feed/weight gain, mortality or carcass characteristics. No breast or hip lesions were observed in carcasses from any of the groups. The weight and structure of the adrenal glands were similar across all groups although the staining of medullary tissue of birds was most intense in the highest stocking density group. As stocking density increased, so did moisture and gait score, hock and foot pad burn scores, and the feather score was adversely affected. CONCLUSIONS: The data showed that the relationship between stocking density and productivity traits was not linear in nature, in accordance with other studies. Under the conditions of the current study, the performance, mortality and carcass characteristics of broilers grown at densities of 10, 15 and 20 birds per m2 were similar. There were some welfare implications at high population densities as indicated by adverse effects on litter quality, gait scores and the incidence of hock and foot pad burns. 相似文献
9.
Kwasi Bannor Richard Amarnath Krishna Kumar Gupta Oppong-Kyeremeh Helena Abawiera Wongnaa Camillus 《水稻科学》2020,27(1):56-66
The factors affecting the adoption of modern varieties(MVs) of rice and impact on poverty in Odisha, India were discussed. A total of 363 households from Cuttack and Sambalpur districts of Odisha via multistage sampling technique participated in the survey. The Cragg's Double hurdle model was used to model the determinants of adoption and intensity of adoption of MVs of rice, and the propensity score matching was used to analyze the impact of adoption on poverty. The results showed that age, education, risk aversion, land size, yield, perception of MVs as high yielding, resistant to diseases and availability of MVs positively influenced the decision to adopt. However, variables such as household size, experience of a farmer, off-farm job participation, amount of credit received, cost of seeds, insecticides and fertilizers negatively influenced the adoption of MVs. Intensity of adoption of MVs was negatively influenced by experience of a farmer, cost of fertilizer and marketability of MVs, and positively affected by household size, risk aversion, land size, cost of insecticides, perception of MVs as high yielding and availability of MV seeds. Poverty incidence, gap and severity were high among non-adopters to adopters of MVs. After matching adopters and non-adopters of MV groups using four different algorithms of nearest neighbour matching, stratification matching, radius matching and kernel matching, the impact of MV adoption resulted in higher per capita monthly household expenditure by about US$ 52.82 to US$ 63.17. 相似文献
10.
1. The aim of the present study was to investigate the effect of an enzyme cocktail composed of xylanase, amylase and protease on the performance and nutrient utilisation of broiler starters fed on a maize-based diet. A maize/soy-based control diet was formulated to be marginal in apparent metabolisable energy (AME) and amino acids and this diet was fed without or with two concentrations (250 and 500 g/tonne) of the exogenous enzyme cocktail. 2. Growth performance was measured over a 21-d period after which ileal contents were collected for measurement of digestible energy, nitrogen and dry matter. Excreta were collected from d 17 to 20 post-hatch and used to determine the AME, and retention of nitrogen and dry matter. 3. Supplementation of the control diet with 250 and 500 g/tonne of the enzyme cocktail resulted in enhanced performance of the chicks (1.4 and 8.3%, respectively, for weight gain and 1.2 and 2.2%, respectively, for feed per gain), but the improvements were significant (P < 0.05) only at 500 g/tonne. 4. Addition of both 250 and 500 g/tonne improved AME, nitrogen-corrected AME and dry matter retention compared with the control though the improvements were greater with the higher dose. These effects were also reflected in the apparent ileal digestibility coefficients of dry matter, nitrogen and energy, with 500 g/tonne of the enzyme cocktail improving ileal digestible energy by 3.4%. 5. These results demonstrate that a cocktail of exogenous enzymes containing xylanase, amylase and protease is effective in improving the performance of broiler chicks fed on a maize/soybean-meal-based diet. However, these benefits may be dose-dependent and so an economic analysis involving ingredient and enzyme pricing and the relative performance and digestibility enhancements could allow the end user to select the most economical dose to maximise return on investment. 相似文献