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   804篇
  免费   44篇
  国内免费   70篇
林业   13篇
农学   12篇
基础科学   6篇
  17篇
综合类   182篇
农作物   4篇
水产渔业   1篇
畜牧兽医   681篇
植物保护   2篇
  2024年   1篇
  2023年   15篇
  2022年   36篇
  2021年   51篇
  2020年   28篇
  2019年   33篇
  2018年   18篇
  2017年   34篇
  2016年   23篇
  2015年   22篇
  2014年   34篇
  2013年   38篇
  2012年   48篇
  2011年   56篇
  2010年   42篇
  2009年   51篇
  2008年   42篇
  2007年   39篇
  2006年   37篇
  2005年   40篇
  2004年   31篇
  2003年   25篇
  2002年   22篇
  2001年   21篇
  2000年   10篇
  1999年   17篇
  1998年   11篇
  1997年   8篇
  1996年   3篇
  1995年   8篇
  1994年   11篇
  1993年   15篇
  1992年   17篇
  1991年   9篇
  1990年   3篇
  1989年   4篇
  1988年   5篇
  1987年   1篇
  1985年   1篇
  1982年   4篇
  1979年   1篇
  1975年   1篇
  1956年   2篇
排序方式: 共有918条查询结果,搜索用时 15 毫秒
81.
本试验旨在研究黄花蒿乙醇提取物对奶山羊乳腺阴外动脉血和乳静脉血中共轭亚油酸(CLA)等脂肪酸含量的影响.选用9只健康、体重(38±3) kg的泌乳期[泌乳天数(210±15)d]关中奶山羊,随机分为3组,每组3只羊,对照组、Ⅰ组和Ⅱ组奶山羊分别饲喂0、7.26和12.10 g/d黄花蒿乙醇提取物.经预试期30 d后,分...  相似文献   
82.
鲁西南地区青山羊种质资源调查与分析   总被引:1,自引:0,他引:1  
许腾 《中国畜牧兽医》2011,38(1):148-151
济宁青山羊是中国著名的裘用地方山羊品种,作者分析了青山羊的选育历史、体型外貌、生产性能等种质特性,同时对青山羊种质资源的保护和利用提出了建议。  相似文献   
83.
采用国产HIT-5型生物活体自动植冰冷冻仪,先后将33枚浏阳黑山羊7日龄胚胎进行冷冻,在-196℃的液氮中保存10.5±6.12d.将其中13枚形态结构基本正常的胚胎移植给7只同期发情的本地母山羊,结果有2只受体妊娠,产羔3只,受体妊娠率为28.57%(2/7),自制冻胚移植成功率为23.08%(3/13).  相似文献   
84.
南江黄羊冬季不同饲养方式的效果研究   总被引:1,自引:0,他引:1  
南江黄羊在大巴山区生态条件下,在120d的冬季中,采取“舍饲”饲养方式,可获得周岁公羊日增重164.50g,只平净增效益31.30元;幼龄(6月龄以下)羊达到平均日增重78.13g,成活率95.24%的生产水平。  相似文献   
85.
应用改良甲苯胺蓝染色法(MTB)观察了大鼠泌乳期和静止期乳腺肥大细胞的分布、形态、数量变化规律.并用阿尔新蓝一番红鉴别染色法(AB-S)进行了细胞化学分型研究。结果:AB-S染色显示,大鼠乳腺只存在黏膜型肥大细胞;无论是泌乳期还是静止期。乳腺肥大细胞大多分布于腺泡间和小叶问结缔组织中。细胞的形态各异,但细胞数量在静止期和泌乳期有显著差异。泌乳期的乳腺肥大细胞数量明显减少(P<0.01)。乳腺肥大细胞的动态变化,可能与乳腺泌乳期腺泡上皮的生长和静止期腺泡问结缔组织细胞增生等结构变化有关。  相似文献   
86.
冰川棘豆对山羊的毒性试验   总被引:1,自引:0,他引:1  
10只杂种奶山羊随机等分为试验组和对照组,试验组羊按每日10g/kg的剂量饲喂冰川棘豆干粉,定期采血,测定血液常规指标和生化指标,进行病理学检验。结果表明,RBC、Hb、PCV、MCH、MCV、MCHC显著低于对照组(P〈0.01),淋巴细胞出现空泡变性。试验组羊血清碱性磷酸酶(AKP)活性,从试验的第7天起持续升高;从试验的第14天起,血清谷草转氨酶(GOT)、乳酸脱氢酶(LDH)活性,尿素氮(BUN)含量明显高于对照组;在试验的35~49d,血清淀粉酶活性持续升高,与对照组比较差异显著(P〈0.05或P〈0.01);从试验的第7天起,血清α-甘露糖苷糖(AMA)活性显著低于对照组(P〈0.01),说明冰川棘豆对心、肝、肾、脑等器官有一定的毒害作用,冰川棘豆中含有吲哚兹啶生物碱。病理组织学检查中发现,心、肝、脾、肺、肾、脑、卵巢等组织普遍发生空泡变性。  相似文献   
87.
In experiments on swine and goats the renal excretion of digoxin was examined, and it was found that the renal clearance of non-protein-bound digoxin in swine was lower than creatinine clearance which expresses filtration clearance. Correlation analysis showed that the renal clearance of digoxin in swine was not significantly influenced by the concentration of non-protein-bound digoxin in plasma and the pH of the urine, while there was a significant positive correlation between the clearance and the urine flow rate (Table 4). On the other hand, the renal clearance of digoxin in goats was significantly influenced by the concentration of non-proteinbound digoxin in plasma and by urine pH (Table 4). From these results it is concluded that glomerular filtration and back-diffusion are involved in the renal handling of digoxin in both swine and goats. In addition active tubular secretion is also involved in the renal excretion of digoxin in goats.  相似文献   
88.
Previous attempts to transfer embryos non-surgically to heifers have been rather discouraging. The present experiment describes a simple non-surgical technique where the 6½–7½ -day old embryo is placed in a 0.25 ml ministraw, fitted into a common insemination gun and transferred cervically to synchronized lactating dairy cows. Thirty-two viable embryos were transferred to the middle part of the uterine horn ipsilateral to the ovary containing the corpus luteum. It was easy to pass the cervix, and most embryos could be deposited in the horn within 1 or 2 min. Eighteen animals were diagnosed pregnant (56% ). It is conceivable that the easy atraumatic transfers and good management (feeding, oestrus control) of the recipients contributed to the high pregnancy rate.  相似文献   
89.
Two 4 x 4 Latin square design experiments were carried out. In experiment 1, four mature Anglo-Nubian x Fiji local goats, pre-experimental body weight 25.0 +/- 0.6 kg, 22-24 months old, were used to study the effect of supplementation of a basal diet of maize stover with Erythrina variegata (EV), Gliricidia sepium (GS) and Leucaena leucocephala (LL) on dry matter intake (DMI) and nutrient digestibility. Maize stover treated with urea was used as a control diet. E. variegata was higher in crude protein content than LL or GS. The DMI of the urea treated stover diet was significantly lower (p < 0.05) than that of the diets of untreated stover supplemented with forage legumes. The DMI was significantly lower (p < 0.05) in the GS diet than in the EV or LL diets. Significant (p < 0.05) differences existed between the urea-treated stover and the diets of stover supplemented with forage legumes in the digestibility of dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), organic matter (OM) and energy. In experiment 2, four mature goats, pre-experimental body weight 27.0 +/- 0.3 kg, 24-28 months old, were used to measure their response when the urea-treated maize stover and the maize stover and forage legume diets were sprayed with molasses. The intake of the urea-treated stover diet sprayed with molasses was significantly lower (p < 0.05) that that of the maize stover/forage legume diets sprayed with molasses. The DMI of the diets improved with the addition of molasses. The DMI among the goats offered the maize stover/forage legume diets + molasses did not differ significantly. (p > 0.05). Statistically significant (p < 0.05) differences were obtained in this second study between the urea-treated stover and the stover supplemented with forage legumes in the digestibility of DM, CP, NDF, OM and energy. The stover supplemented with forage legumes had a higher (p < 0.05) nutrient digestibility. The present studies demonstrated that the use of forage legumes as protein supplements improved the feed quality of maize stover in the diets of mature goats. It is suggested that molasses should be sprayed on fresh leaves of Gliricicia sepium and other forage legumes that are initially rejected, in order to improve acceptance and DMI when fed to ruminant animals in confinement or in a cut-and-carry system of production.  相似文献   
90.
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