首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   91篇
  免费   9篇
  国内免费   4篇
农学   1篇
综合类   35篇
农作物   2篇
畜牧兽医   66篇
  2024年   1篇
  2023年   1篇
  2022年   2篇
  2021年   5篇
  2020年   2篇
  2019年   4篇
  2018年   4篇
  2017年   8篇
  2016年   4篇
  2015年   3篇
  2014年   7篇
  2013年   10篇
  2012年   7篇
  2011年   4篇
  2010年   3篇
  2009年   1篇
  2007年   5篇
  2006年   2篇
  2005年   5篇
  2004年   2篇
  2003年   3篇
  2002年   1篇
  2001年   1篇
  2000年   2篇
  1998年   3篇
  1997年   2篇
  1996年   2篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
排序方式: 共有104条查询结果,搜索用时 48 毫秒
51.
The study aimed to investigate the effects of vitamin E injection for the prevention of transport stress on ewes. Kivircik ewes (2–3 years old, = 24) were randomly separated into three groups; G1 (Control) and G2 treated with 14 ml. saline as the placebo, G3 treated with 2100 IU/ind. DL-alpha-tocopherol acetate prior to transport. G2 and G3 were transported at 80 km/h for 4 h on a truck. Serum samples were obtained before (T0) and after (T1) transport. Serum cortisol, catalase, IgG, ceruloplasmin, C-reactive protein, complement component 4, interleukin-1 beta, tumour necrosis factor-alpha, glutathione peroxidase (GPx), superoxide dismutase, malondialdehyde analyses performed by ELISA, and serum alpha-tocopherol concentrations were evaluated by HPLC-UV. Wilcoxon and Kruskal–Wallis tests were used for statistical assessments (p < 0.05). Alpha-tocopherol concentrations were founded 1.22 ± 0.82, 0.27 ± 0.14 and 0.14 ± 0.07 µmol/L, respectively, in G1, G2 and G3 at T1. Alpha-tocopherol concentration decreased significantly in G2 between T0 and T1. GPx concentrations were increased twofold in G2 and G3 between T0 and T1 (p < 0.01). As a result, G2 alpha-tocopherol concentrations decreased but, the stress and oxidative parameters tested in this study were not affected by treating 2100 IU/ind. DL-alpha-tocopherol acetate before transport.  相似文献   
52.
以绵羊卵泡颗粒细胞为研究对象,采用体外培养细胞的方法,分别于不同时间收集细胞培养液,用放射免疫法(RIA)测定雌二醇和孕酮含量。结果表明:不同培养时间对卵泡颗粒细胞分泌雌二醇影响显著,24h、36h、48h之间差异均极显著(P<0.001),并随时间延长,雌二醇含量呈下降趋势;在不同时间收集的细胞培养液中检测不到孕酮。  相似文献   
53.
54.
为探明辽西地区舍饲条件下母羊繁殖性能与缺硒的关系,本研究在对舍饲母羊繁殖性能调查和血硒含量测定的基础上,系统比较了添加不同量酵母硒对母羊繁殖性能的影响。结果表明,辽西地区3个半舍饲和3个舍饲羊群全血硒含量分别为0.0167μg/mL和0.0126μg/mL,舍饲和半舍饲羊群间血清硒含量的差异显著(P<0.05),低于正常机体需要量的0.06μg/mL;舍饲羊群的发情率、受胎率和产羔率等指标显著低于半舍饲羊群相关指标(P<0.05)。硒补充试验结果表明,无论是酵母硒还是富硒舔砖均对繁殖母羊的发情率、受胎率、产羔率和繁殖成活率有所改善,且添加0.2 mg/kg和0.3 mg/kg的酵母硒对以上各指标的影响更为显著。以上研究结果为缺硒地区繁殖母羊补硒方案提供了重要参考。  相似文献   
55.
将15只甘肃高山细毛羊按体重分为三组:Ⅰ组注射生理盐水作为对照组;Ⅱ组埋植MLT(36mg);Ⅲ组埋植MLT(36mg)+孕马血清激素(400IU),研究MLT对体重、发情的影响。结果表明:0~15d、15~30dMLT+孕马血清激素处理组体增重显著低于对照组(P<0.05);30~45d、45~60dMLT组体增重也显著低于对照组(P<0.05),其它时期各组间均无显著差异性,总增重和末重也无显著差异性(P>0.05)。与对照组相比,实验组第一只母羊发情时间提早30d,发情率提高40%。  相似文献   
56.
试验探讨了通过导入体大高产澳血公羊对甘肃高山细毛羊F1、F2代周岁母羊主要生产性能的影响。从体侧毛长、体重、剪毛量、纤维直径、净毛率等主要生产性能进行了分析比较,为培育甘肃高山细毛羊体大高产品系奠定基础。结果表明:(1)F1代周岁母羊与同龄甘肃高山细毛羊超细品系母羊相比,羊毛长度增长了0.398cm(P0.01),体重增加了3.7949kg(P0.01),剪毛量有所增加(P0.01),毛纤维变粗(P0.01),净毛率没有变化。(2)F2代周岁母羊羊毛细度变化不显明,与甘肃高山细毛羊超细品系母羊相比变粗了1.294μm(P0.01);毛长和剪毛量有所提高(P0.01);体重分别较甘肃高山细毛羊和甘肃高山细毛羊超细品系母羊增加了3.3051kg(P0.01)、1.0648kg(P0.05);净毛率没有变化(P0.05)。  相似文献   
57.
58.
本研究分析饲喂苜蓿(Medicago sativa)干草对越冬母羊体质量增加和日粮消化率的影响。从5组(SA1、SA2、SA3、SA4、SA5)暖季放牧母羊中各选取18只健康母羊,随机分为对照组和试验组,每组9只,对照组和试验组平均体质量差异不显著(P>0.05)。对照组不使用苜蓿干草,试验组中苜蓿干草占日粮干物质的比例为11.4%~17.1%。结果表明,SA2、SA3、SA5试验组使用苜蓿干草提高日粮粗蛋白含量并保持适宜的能量蛋白比[消化能(MJ)∶粗蛋白(g)为(1.06~1.08)∶10],可使越冬母羊不掉膘并降低日粮成本。试验组日粮的粗蛋白和中性洗涤纤维消化率均高于对照组,而干物质消化率均低于对照组。  相似文献   
59.
We investigated the effects of gonadotropin releasing hormone (GnRH) agonist on expressions of GnRH receptor (GnRHR), follicle‐stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) proteins in the ovaries and follicular development in the ewes. Forty‐two pre‐pubertal ewes were assigned to experimental groups 1 to 5 (EG‐I to EG‐V) and control group (CG). Ewes in EG‐I, EG‐II and EG‐III were subcutaneously injected with 200, 300 or 400 μg alarelin antigens twice (on days 0 and 14), respectively. Ewes in EG‐IV and EG‐V were subcutaneously injected with 200 μg and 300 μg alarelin antigen four times (on days 0, 7, 14 and 21). Ewes in CG were subcutaneously injected with a solvent twice (on days 0 and 14). Serum concentrations of GnRH antibody in the EGs increased and were higher than (P < 0.05) that of CG from day 14 to day 60. GnRH antibody concentrations in EG‐IV and EG‐V were higher than that in EG‐I, EG‐II and EG‐III from days 35 to 45. Expressions of GnRHR protein in EG‐IV and EG‐V were lower than that in CG (P < 0. 01). Expressions of FSHR and LHR proteins in EGs increased. Levels of FSHR and LHR proteins in EG‐IV and EG‐V (P < 0.05) were higher than CG. Ovarian weights in EGs increased. Values of follicle vertical diameter, follicle transverse diameter, follicle wall thickness, follicle externatheca thickness and follicle internatheca thickness in EG‐III and EG‐V were greater than other groups. Primordial follicles and primary follicles developed quickly in alarelin‐immunized animals. Secondary follicles and mature follicles became more abundant. Mitochondria, mitochondrial cristaes and cortical granules increased. Serum FSH concentrations of EGs remained higher than that in CG from days 28 to 70 (P < 0.05). Alarelin immunization stimulated GnRH antibody production, suppressed expression of GnRHR protein, enhanced expressions of FSHR and LHR proteins in ovaries, promoted FSH secretion and thereby accelerated the development of ovaries and follicles in ewes.  相似文献   
60.
The effects of allowance of extended (deferred) grazed herbage (AEGH) and herbage allocation management (HAM) were studied in ewe lambs (248) and late‐gestation ewes (152), respectively, on commercial farms in south‐east Ireland in 2005–06. In Experiment 1, which consisted of four treatments, the effects of AEGH (0·75, 1·25 and 1·75 kg DM per head daily) and concentrate supplementation (0·5 kg per head daily with the 0·75 kg DM herbage allowance) on lamb performance during the extended grazing (16 December to 3 March) and subsequent grazing (4 March to 11 August) seasons were evaluated. Increasing AEGH increased herbage intake linearly (P < 0·001) and live weight (P < 0·001) at the end of extended grazing and the subsequent grazing season. In Experiment 2, single‐ and twin‐bearing ewes were allocated to either a conventional (single‐ and twin‐bearing ewes grazed separately) or leader–follower system (twin‐ and single‐bearing ewes, as leaders and followers respectively) of HAM from 30 January to 24 March. The same quantities of herbage were offered daily for each system. System of HAM affected ewe condition score at lambing but did not alter (P > 0·05) subsequent lamb birth or weaning weights. It is concluded that increasing AEGH to ewe lambs increased liveweight gain during extended grazing and resulted in heavier animals in mid August of the subsequent grazing season. For ewe lambs each 1 kg concentrate DM had the same feed value as 2·4 kg DM AEGH. Use of a leader–follower system for ewes in late pregnancy did not alter lamb birth weight or subsequent performance.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号