全文获取类型
收费全文 | 219篇 |
免费 | 18篇 |
国内免费 | 7篇 |
专业分类
林业 | 24篇 |
农学 | 9篇 |
基础科学 | 13篇 |
13篇 | |
综合类 | 62篇 |
农作物 | 5篇 |
水产渔业 | 12篇 |
畜牧兽医 | 93篇 |
园艺 | 6篇 |
植物保护 | 7篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 6篇 |
2017年 | 12篇 |
2016年 | 14篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 11篇 |
2011年 | 13篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有244条查询结果,搜索用时 15 毫秒
31.
M. K. Malde I. E. Graff H. Siljander‐Rasi E. Venäläinen K. Julshamn J. I. Pedersen J. Valaja 《Journal of animal physiology and animal nutrition》2010,94(5):e66-e76
In general, there is a lack of scientific documentation of nutritional value of marine by‐products. The bone fraction from fish has been regarded as waste. Due to the high mineral content of fish bones, this material can be well suitable as a natural calcium source. In the present study, apparent calcium absorption of different fish bone sources was tested using growing pigs. The experimental diets consisted of boiled salmon frames, or salmon, saithe or cod bones treated with enzymes. Calcium carbonate (CaCO3) was used as control. The experimental diets were formulated to contain 0.7% total calcium of which the added calcium source to be tested contributed about 71% (study 1) and 86% (study 2). Except for the calcium and phosphorus sources, the animals received similar basal diets. Apparent calcium digestibility coefficient was calculated using yttrium as indicator (both studies) and was based on complete collection of faeces and urine (study 2). The experimental design was parallel and cross‐over in study 1 and study 2, respectively. In study 1, piglets getting salmon bone treated with enzymes had significantly higher calcium absorption than piglets getting boiled fish bone or calcium carbonate. Therefore, in the second study only enzymatically treated fish bones were included. The higher calcium absorption from enzymatically treated salmon bone was also found in study 2, but this time not significant. Calcium from boiled salmon bones in study I, and from enzymatically treated saithe and cod bones in study II were absorbed as well as the calcium carbonate control. The results indicate that fish bones may be a useful and well absorbed calcium source. Due to the high mineral content of the bone fraction, salmon bones can be well suitable as a natural calcium and phosphorus source in, for example, food, feed or as supplement. 相似文献
32.
在肉仔鸡日粮中分别添加0.5%、1%和2%由黄荆、黄芪、白术、紫菊、山药、常春藤、四季青、白芍、陈皮、甘草配成的补益生长素进行饲喂效果试验研究。结果表明,含1%补益生长素的试验2组比未添加补益生长素的对照组以及含0.5%补益生长素的试验1组和含2%补益生长素的试验3组肉仔鸡平均日增重分别提高12.89%、10.24%和12.26%(P0.05),饲料增重比分别降低了12.91%、8.17%和9.59%(P0.05),日粮中分别添加0.5%和2%补益生长素的试验组与对照组差异均不显著(P0.05)。添加补益生长素以1%比例为佳,并能改善肉仔鸡生产性能。 相似文献
33.
为探讨NPN(non protein nitrogen 非蛋白氮 简称NPN)补充料在奶牛养殖业中的作用,选取相关材料和方法进行研究。中国荷斯坦奶牛32头随机分为试验组和对照组,每组16头。试验组在精料中用NPN补充料取代一定数量的常规蛋白质补充料,对照组饲喂常规饲料,不添加NPN补充料。经过60天的试验,结果表明:试验组奶牛总产奶量16108 kg,比对照组的15289 kg增产819 kg,平均每头每日增产0.85 kg,以当地鲜奶时价2 元/kg计,计算出日增收1.7 元。再来计算饲料成本,在用NPN补充料替换出常规蛋白质补充料胡麻饼时,精饲料总成本降低544 元,即试验组比对照组饲料成本节省544 元,通过相关计算可得试验组平均每头每日节约饲料成本0.57 元。从而得出NPN补充料对奶牛产奶量及经济效益的影响结果,对其在生产中推广应用有指导作用。 相似文献
34.
本试验以6月龄伊犁马驹为试验动物,饲喂不同水平的精料补充料,通过全收粪、收尿法进行消化代谢试验,探究饲喂不同水平的精料补充料对6月龄伊犁马消化代谢、血液生化指标及体增重的影响,为6月龄伊犁马驹的科学饲喂提供依据。试验选用平均体重为(145.28±1.69) kg的6月龄断奶伊犁公马驹20匹,随机分为4组,每组5匹,分别为试验Ⅰ、Ⅱ、Ⅲ及Ⅳ组,各组每匹马每天饲喂4 kg苜蓿干草,在此基础上分别饲喂精料补充料0.4、0.6、0.8、1.0 kg。进行20 d的消化代谢试验,其中预试期16 d,正试期4 d。结果表明,随精料补充料饲喂水平的增加6月龄伊犁马马驹对营养物质的摄入量,干物质、有机物、粗蛋白质、钙的消化量,以及消化能、代谢能、氮沉积率、钙沉积率均增加,对6月龄伊犁马马驹血浆中总蛋白、球蛋白、白蛋白及血液尿素氮含量均无显著影响(P > 0.05),但6月龄伊犁马马驹血液中球蛋白的含量有增加的趋势,血液中尿素氮的含量有降低的趋势;此外试验期内平均日增重随精料补充料饲喂水平的增加呈上升趋势。因此,增加6月龄伊犁马马驹精料补充料的饲喂水平可提高营养物质摄入量、消化率及沉积率,还可增强机体免疫能力、促进氮沉积并提高马驹的平均日增重。 相似文献
35.
在2012年4月23日至26日高含沙的黄河水向东昌湖补水期间,分别对湖面12个监测点及从入湖口到出湖口的纵断面 5个监测点同步取样、测流和测沙,从整体到局部分析了悬浮泥沙与叶绿素a浓度的变化。结果表明:补水前,湖区叶绿素a平均浓度为4.07 μg·L-1,补水后达到7.74 μg·L-1,其中黄河补水贡献了21.1%。在从入湖口到出湖口的纵断面中,入湖口附近监测点A、B叶绿素a浓度增幅由大变小,流速、悬浮泥沙均出现明显高峰,监测点C、D、E依次呈现递减趋势。补水期间,5个纵断面监测点叶绿素a浓度与悬浮泥沙含量呈现极显著负相关,相关系数达-0.81,而补水前后其相关系数仅在-0.43左右。湖面细颗粒悬浮泥沙占主导的监测点,叶绿素a浓度增幅大,反之,粗颗粒占主导的监测点,叶绿素a浓度增幅小,故可推断悬浮泥沙对叶绿素a的影响表现为“高浓度粗颗粒悬浮泥沙抑制叶绿素a浓度的增加,细颗粒或胶粒悬浮泥沙促进叶绿素a浓度的增加”,但这种影响只在补水短期内显著。因此,悬浮泥沙在黄河补水期间是影响叶绿素a浓度变化的主要水环境因素之一。 相似文献
36.
37.
High insulin concentrations are a common clinical feature of equine metabolic syndrome (EMS) and insulin dysregulation. Hyperinsulinemia can induce laminitis, so reduction of insulin concentrations in response to an oral challenge should decrease risk. In human studies, diets containing a polyphenol (resveratrol) led to improvements in insulin sensitivity. In rodents, the addition of leucine to a resveratrol supplement caused a decrease in the amount of resveratrol needed to achieve a clinical effect. We hypothesize a supplementation with a low dose of a synergistic polyphenol and amino acid blend including leucine (SPB+L) would improve metabolic health in EMS/insulin dysregulated horses. Fifteen EMS/ID horses received a high or low dose of SPB+ L daily for 6 weeks. Insulin during an oral sugar test (OST), body condition score, weight, baseline high-molecular-weight (HMW) adiponectin, triglycerides, nonesterified fatty acids, and tumor necrosis factor alpha were assessed before supplementation (PRE) and after supplementation (POST) via paired Student’s t-tests and a repeated-measures mixed-model analysis of variance (significant at P < .05). There were no differences between doses. Horses in the POST group weighed significantly less, had significantly higher baseline HMW adiponectin concentrations, and had significantly lower insulin concentrations at 60- and 75-minute time points (P < .05). Insulin concentrations of the horsesin the POST group, but not in the PRE group, were lower and similar to results from the study conducted three years before the present study (PRIOR) for 0- and 60-minute time points (P < .002). An increased HMW adiponectin level supports increasing insulin sensitivity after supplementation. These results suggest that SPB + L supplementation at either dose leads to improvements in the clinical manifestations of EMS/insulin dysregulation, potentially reducing laminitis risk. 相似文献
38.
对40例牛、马原发性肠炎和消化不良性腹泻临床病例进行了口服补液、抗菌止泻药物(口服补液盐液、痢菌净及泻速宁2号)治疗试验。结果表明:口服补液盐液各成份均可吸收,具有补充水、葡萄糖、钠、钾、氯及碳酸氢盐的作用;口服补液盐液与抗菌止泻药物配伍,有协同作用,使用简便、安全。 相似文献
39.
40.
[目的]优化高浓度玉米生料酒精发酵的工艺。[方法]在外环流式发酵罐中,考察了起始发酵醪加入量、起始添加时间、添加间隔时间及每批添加量等因素对玉米生料酒精发酵的影响,并将优化工艺应用于高浓度酒精的发酵。[结果]按料水比1.0∶2.3,添加100AUN/g原料的生淀粉酶获得初始发酵醪,取30%加入外环流式发酵罐,接种发酵,至2 h起每30 min添加5%的剩余发酵醪,30℃恒温发酵72 h,发酵终点酒精度达到120.0 g/L,淀粉利用率为90.08%,与普通工艺相比酒精度提高了15.3%。将该工艺进一步应用于高浓度生料酒精发酵,当料水比为1.0∶1.8时,酒精度达到133.6 g/L,淀粉利用率为86.6%。[结论]该试验提出的分批添加强制循环生料酒精发酵工艺能明显提高酒精浓度和淀粉利用率,有利于高效、清洁酒精生产工艺的建立。 相似文献