全文获取类型
收费全文 | 91篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
农学 | 5篇 |
基础科学 | 1篇 |
23篇 | |
综合类 | 15篇 |
农作物 | 12篇 |
水产渔业 | 10篇 |
畜牧兽医 | 36篇 |
出版年
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有102条查询结果,搜索用时 281 毫秒
81.
82.
Efficiency of microbial phytase supplementation in diets formulated with different calcium:phosphorus ratios,supplied to broilers from 22 to 33 days old
下载免费PDF全文
![点击此处可从《Journal of animal physiology and animal nutrition》网站下载免费的PDF全文](/ch/ext_images/free.gif)
L. de P. Naves P. B. Rodrigues L. do V. Teixeira E. C. de Oliveira M. M. Saldanha R. R. Alvarenga A. D. Corrêa R. R. Lima 《Journal of animal physiology and animal nutrition》2015,99(1):139-149
An experiment was conducted with broilers from 22 to 33 days of age to evaluate the efficiency of six microbial phytases supplemented in diets (1500 FTU/kg) that were formulated with three different calcium:available phosphorus (Ca:Pavail) ratios (4.5:1.0, 6.0:1.0 and 7.5:1.0). A positive control diet without phytase was formulated with a Ca:Pavail ratio of 7.5:3.4 to meet the nutritional requirements of the broilers. The P and ash contents of the tibia, magnesium in the plasma, performance, balance and retention of phytate phosphorus (Pphyt), intake of total P and nitrogen (N), nitrogen‐corrected apparent metabolizable energy and apparent digestibility of dry matter of the diets were not influenced (p > 0.05) by the type of phytase or the dietary Ca:Pavail ratio. However, there was an interaction (p < 0.05) between the phytase type and the Ca:Pavail ratio for the retention coefficients of total P, Ca and N. Phytase B resulted in the highest Ca deposition in the tibia (p < 0.01). Phytases D, E and F reduced the Ca concentrations in the tibia (p < 0.01) and plasma (p < 0.05). Phytase D increased the P level in the plasma and decreased the total P excretion (p < 0.01). Phytases E and F increased Ca excretion, while phytase A reduced it (p < 0.01). Regardless of the phytase type, increasing the dietary Ca:Pavail ratio reduced (p < 0.05) the plasma P concentration and the excretion of total P and N and, conversely, increased (p < 0.05) the plasma concentration, intake and excretion of Ca. For the rearing period evaluated, it is possible to reduce the Pavail of the diet to 1.0 g/kg when Ca is maintained at 7.5 g/kg, and the diet is supplemented with 1500 FTU of phytase A, C, D or E/kg. This diet allows the maintenance of performance and adequate bone mineralization, and it improves the Ca, total P and Pphyt utilization in addition to reducing the excretion of N and P into the environment. 相似文献
83.
84.
85.
Rainbow trout, Oncorhynchus mykiss, were fed diets containing untreated or phytase-treated soybean meal and corn gluten meal with or without 50 mg supplemental zinc kg–1 to determine if dietary phytate caused a zinc (Zn) deficiency. Fish fed diets containing untreated soybean meal and corn gluten meal without supplemental Zn (basal diet) showed no signs of a Zn deficiency after 170 d of weight gain. Weight gain, carcass protein content, total bone Zn, and alkaline phosphatase and carboxypeptidase B activities were not significantly altered in fish fed the basal diet. Dietary phytate removal and supplemental dietary Zn were not required to prevent Zn deficiency in rainbow trout fed a plant-based diet. Although bone Zn concentrations were reduced in fish fed the basal diet, total bone Zn increased in all fish regardless of dietary treatment. Future assessments of Zn status of fish should be based on changes in Zn-dependent metabolism or total bone Zn rather than on bone Zn concentration. 相似文献
86.
大豆紫色酸性磷酸酶基因GmPAP4启动子结构与活性分析 总被引:2,自引:0,他引:2
【目的】克隆GmPAP4启动子(PAP4-pro),并分析其表达特性,为进一步研究其作用机制奠定基础。【方法】依据GmPAP4 c DNA序列(Gen Bank No.HQ162477),通过比对大豆参考基因组,设计特异引物,克隆GmPAP4启动子序列,通过PLACE与Plant CARE在线生物信息学数据库预测该启动子相关调控元件。构建GmPAP4启动子驱动GUS表达载体(PAP4-pro-GUS)并转化根癌农杆菌GV3101;通过Floral dip法将PAP4-pro-GUS转化拟南芥,利用卡那霉素(Kan)抗性筛选和特异引物的PCR鉴定,最终获得T3转基因拟南芥。通过对T_3转基因拟南芥不同组织GUS染色,分析启动子的组织表达特性,将T3转基因拟南芥通过适磷和植酸磷处理,20 d后,取其根部进行GUS活性和表达分析,研究启动子对不同磷环境的响应。【结果】克隆了GmPAP4上游启动子序列,通过PLACE与Plant CARE在线生物信息学数据库预测显示,GmPAP4启动子除含有启动子核心的调控元件外,还含有(1)组织特异调控元件:as1(根系特异表达调控元件)和Skn-1_motif(胚乳特异表达调控元件);(2)应答元件:TC-rich repeats(逆境胁迫反应调控元件)和Box-W3(真菌应答相关调控元件);(3)结合位点:MBS(MYB转录因子的结合位点)等。不同组织GUS染色结果显示,转基因拟南芥整个根系GUS染色较深,茎、叶中仅微管组织有较明显GUS染色,花瓣微管组织中也能观察到微弱GUS染色。定量PCR结果显示,植酸磷处理条件下转基因拟南芥根系GUS表达比适磷处理提高了1.3倍(P0.05);同时GUS活性测定显示,与适磷处理相比,植酸磷处理条件下转基因拟南芥根系GUS活性提高了1.9倍(P0.05)。【结论】获得大豆GmPAP4启动子,通过不同组织GUS染色和不同磷环境GUS表达分析显示该启动子主要在根部且受低磷信号诱导表达,为诱导型启动子。 相似文献
87.
植酸酶生产菌的筛选及生长条件的研究 总被引:3,自引:1,他引:3
从单胃动物的粪便垃圾堆中分离出一种可分泌植酸酶的青霉 .进一步的研究表明这种青霉培养液最佳的淀粉含量为 40g·L-1.青霉生长与其分泌植酸酶之间存在矛盾 .青霉生长旺盛时产酶少 ,测出的酶活性低 .青霉生长缓慢时产酶多 ,测出的酶活性高 .植酸酶大量分泌前伴随着培养液pH值的急剧下降 相似文献
88.
麦类籽实中植酸酶的活性及体外降解植酸盐效果的研究 总被引:1,自引:0,他引:1
为评价不同麦类籽实中内源植酸酶的活性及其对外源植酸盐的降解能力,以植酸钠为底物,测定5种10个不同品种麦类籽实中植酸酶的活性;在37℃、pH 5.50的条件下,以300 U/kg的浓度加入从麦类籽实中提取的植酸酶,检测了对玉米、豆粕中植酸磷的释放效果。结果表明,燕麦、大麦(垦啤2号)、小麦(东农123)、小麦(东农973821)、小黑麦(5305)、小黑麦(92021)、小黑麦(96026)、小黑麦(8809)、胜利黑麦和黑麦(2号)籽实中植酸酶的活性分别为57.50、143.25、1048.06、725.22、1978.67、2201.65、1713.46、1406.49、5310.89 U/kg和3446.53 U/kg(风干基础);在上述条件下,反应8h,玉米、豆粕中的植酸磷分别释放71.92%和38.94%。 相似文献
89.
G.A. Morales L. Márquez M. Saenz de Rodrigañez L. Bermúdez R. Robles F.J. Moyano 《Aquaculture Nutrition》2014,20(2):172-182
To assess to what extent addition of phytase to a plant‐based diet results in spatio‐temporal changes of phytate, available P, soluble protein, total amino acids and the activity of the main digestive proteases in gilthead sea bream, fish were fed two plant‐based diets with or without phytase. Stomach, proximal intestine and distal intestine contents were monitored for these parameters at 0, 1, 2, 4 and 6 h after feeding. A reduction (P < 0.0001) of the soluble P–IP6 in the stomach when phytase was added to the diet was observed. Within stomach, most of the total P–IP6 was precipitated (86%), possibly due to the low acidification capacity of the sea bream (pH > 4), but 57% of the dietary P–IP6 was dephosphorylated, suggesting that phytase could have the capacity to dephosphorylate insoluble IP6 at such pH. An increment (60%) (P < 0.01) in total gastric protease activity was observed by phytase addition, this being the first demonstration of the in vivo effect of IP6 on the pepsin activity in fish stomach. Gastric pH and residence time of the digesta inside the stomach are critical factors for an efficient phytase action and improve P and N bioavailability in plant‐based diets used in fish aquaculture. 相似文献
90.
Phytase and sodium diformate supplementation in a plant‐based diet improves protein and mineral utilization in rainbow trout (Oncorhynchus mykiss)
下载免费PDF全文
![点击此处可从《Aquaculture Nutrition》网站下载免费的PDF全文](/ch/ext_images/free.gif)
G.A. Morales V. Denstadli S.A. Collins L.T. Mydland F.J. Moyano M. Øverland 《Aquaculture Nutrition》2016,22(6):1301-1311
A basal isonitrogenous and isoenergetic plant‐based diet (Control) was supplemented with either 10 g kg?1 sodium diformate (NaDF), 4000 FTU kg?1 phytase (Phy) or a combination of both additives (NaDF + Phy). Three hundred juvenile rainbow trout with an average weight of 120 g were randomly distributed into 12 fibreglass tanks (300 L). After 65 days of trial, fish fed diets containing phytase, NaDF or the combination of both additives showed a higher growth rate (P < 0.05) compared to fish fed Control diet. NaDF increased feed intake (P = 0.032), while phytase inclusion resulted in a better feed conversion ratio (P < 0.0001) and a higher N retention efficiency (P = 0.02) compared with the Control. Apparent digestibility of P, Ca, Mg and Zn was improved by the use of phytase (P < 0.005) as well as P, Ca and Mg retention efficiency in fish (P < 0.0001). Using 4000 FTU kg?1 phytase in plant‐based diets resulted in a 13% and 50% reduction in N and P loadings, respectively. The use of NaDF in combination with phytase in a plant‐based diet for rainbow trout resulted in a higher weight gain than that when NaDF was used alone. 相似文献