全文获取类型
收费全文 | 133篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
林业 | 4篇 |
农学 | 1篇 |
基础科学 | 1篇 |
3篇 | |
综合类 | 17篇 |
农作物 | 2篇 |
水产渔业 | 9篇 |
畜牧兽医 | 106篇 |
植物保护 | 6篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1911年 | 1篇 |
排序方式: 共有149条查询结果,搜索用时 15 毫秒
1.
The average passage time, the rumen fluid volume and the digestibility of the organic matter were determined in addition to 3 individual feeding experiments with fertility oriented crossbreed ewes, which received pelleted straw-concentrate mixtures. The average passage time of the feed particles through the digestive tract is shorter in pregnant animals than in lactating ones. It is longest in non-pregnant sheep. High quotas of straw and coarse particles prolong the passage time, increasing feed intake and supplements of long straw shorten it. The volume of rumen fluid is lower in ewes fed ad libitum in the stage of late pregnancy and after lactation than during lactation. The rumen fluid volume is also lower in restrictively fed animals during the stage of late pregnancy than during lactation. In animals in the stage of late pregnancy it correlates negatively with the weight of the litter. On an average of all experiments at maintenance level the digestibility of the organic matter in ewes in the 4th month of pregnancy gravidity amounted to 56.6%, in the 2nd month of lactation to 59.8% and in wethers to 59.5% Due to an increase of energy intake from maintenance to 2. maintenance digestibility of the straw-concentrate mixture with 40% straw decreased by 5.5 units and of that with 60% straw by 17.8 units in the period before delivery. Pregnancy in the 4th month resulted in a digestion depression of between 3.0 and 5.8 units. 相似文献
2.
SUMMARY The proposal by the Zoological Parks Board of New South Wales to import 10 southern black rhinoceros (Diceros bicornis) from Zimbabwe as part of an international project for conservation of the species presented the Australian Quarantine and Inspection Service (AQIS) with a unique challenge. This importation is, at least in the modern era, the first importation of live herbivores from the African continent. Many of the serious animal diseases in the world are endemic in parts of Africa. Knowledge of which of these diseases infect wild species and may be transmitted from the wild species to domesticated species, is limited. This paper describes the strategies adopted by AQIS to facilitate the importation of rhinoceros while maintaining protection of Australian consumers, rural industries, domestic livestock and fauna against the entry and spread of unwanted pests and diseases. 相似文献
3.
4.
5.
Influence of the root endophyte Piriformospora indica on the plant water relations,gas exchange and growth of Chenopodium quinoa at limited water availability 下载免费PDF全文
S. Hussin W. Khalifa N. Geissler H.‐W. Koyro 《Journal of Agronomy and Crop Science》2017,203(5):373-384
This study aimed to evaluate the ability of Piriformospora indica to colonize the root of Chenopodium quinoa and to verify whether this endosymbiont can improve the growth, performance and drought resistance of this species. The study delivered, for the first time, evidence for successful colonization of P. indica in quinoa. Hence, pot experiment was conducted in the greenhouse, where inoculated and non‐inoculated plants were subjected to ample (40%–50% WHC) and deficit (15%–20%WHC) irrigation treatments. Drought adversely influenced the plant growth, leading to decline the total plant biomass by 74%. This was linked to an impaired photosynthetic activity (caused by lower gs and Ci/Ca ratio; stomatal limitation of photosynthesis) and a higher risk of ROS production (enhanced ETR/Agross ratio). P. indica colonization improved quinoa plant growth, with total biomass increased by 8% (controls) and 76% (drought‐stressed plants), confirming the growth‐promoting activity of P. indica. Fungal colonization seems to diminish drought‐induced growth hindrance, likely, through an improved water balance, reflected by the higher leaf ψw and gs. Additionally, stomatal limitation of photosynthesis was alleviated (indicated by enhanced Ci/Ca ratio and Anet), so that the threat of oxidative stress was minimized (decreased ETR/Agross). These results infer that symbiosis with P. indica could negate some of the detrimental effects of drought on quinoa growth, a highly desired feature, in particular at low water availability. 相似文献
6.
Zoledronate is a bisphosphonate frequently used for the treatment of hypercalcaemia of malignancy and tumour-associated bone pain in dogs, however, there is a paucity of information regarding its use in veterinary medicine. The aim of this retrospective study was to report the tolerability of zoledronate in the palliative treatment of cancer-bearing dogs and secondarily to to assess the efficacy of zoledronate for the treatment of hypercalcaemia of malignancy. Thirty-seven dogs (22 with tumour-associated bone pain and 15 with hypercalcaemia of malignancy) that received 114 zoledronate infusions were included. Tolerability was assessed by the absence of post-zoledronate hypocalcaemia or other adverse events as defined by Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events criteria. Efficacy was assessed by comparison of available ionized calcium levels before and after zoledronate administration in hypercalcaemic dogs. In 79% of zoledronate infusions, no adverse events were reported. The majority of adverse events which occurred in the other 21% of infusions could be attributed to concurrent chemotherapy or the underlying neoplastic disease. There was a small but significant increase in creatinine following treatment with zoledronate, however, none of the dogs developed clinically significant renal disease. In eight hypercalcaemic dogs with available ionized calcium following zoledronate administration, ionized calcium decreased rapidly within 7 days following treatment with zoledronate. Zoledronate is well-tolerated with few recorded adverse events, however, monitoring of serum creatinine is advised. Zoledronate seems to be effective in the treatment of hypercalcaemia of malignancy. 相似文献
7.
8.
[目的]分析研究洪泽湖湖滨地区植物群落对湿地水环境的净化效果,为该区生态修复提供参考依据。[方法]以洪泽湖湿地国家级自然保护区典型湖滨带为研究对象,通过对该区的水草区和无草区环境特征进行野外调查,并结合室内试验,测定湖泊湿地水体的营养盐(N和P)、化学需氧量(COD)及透明度(SD)含量的变化,定量分析水生植被在生长过程中对湖泊湿地生态系统中水环境的净化效果,并对其可能存在的影响因素进行探讨。[结果]水生植被对洪泽湖湿地水环境中TN、TP、COD、Chla的去除作用及对SD含量变化有较明显的影响。水生植物之间的竞争可以抑制藻类的生长,减轻水体的富营养化情况。[结论]该试验为研究洪泽湖湖滨带生态修复及增强其自净能力提供理论依据。 相似文献
9.
[目的]研究在放牧补饲条件下不同品种肉牛的早期生长发育与经济效益。[方法]选择3月龄断奶新褐杂牛(新疆褐牛与本地牛)、安杂牛(安格斯与本地牛)、荷斯坦牛、土种牛31头,按品种分组开展夏草场放牧补饲试验。[结果]安杂牛、荷斯坦牛、新褐杂牛和土种牛补饲日增重分别为0.51、0.55、0.56、0.25 kg/d,安杂牛、荷斯坦牛、新褐杂牛的日增重与土种牛相比差异极显著(P0.01)。新褐杂牛、荷斯坦牛、安杂牛的放牧补饲效果较土种牛好,新褐杂牛、荷斯坦牛、安杂牛和土种牛的投入产出比分别为1∶2.32、1∶2.29、1∶2.12和1∶1.02,放牧补饲经济效益明显。[结论]早期断奶对后期放牧补饲肉牛的生长发育具有促进作用。 相似文献
10.
Oceanographic investigation of the American Samoa albacore (Thunnus alalunga) habitat and longline fishing grounds 总被引:1,自引:0,他引:1
RÉKA DOMOKOS MICHAEL P. SEKI JEFFREY J. POLOVINA DONALD R. HAWN 《Fisheries Oceanography》2007,16(6):555-572
The American Samoa fishing ground is a dynamic region with strong mesoscale eddy activity and temporal variability on scales of <1 week. Seasonal and interannual variability in eddy activity, induced by baroclinic instability that is fueled by horizontal shear between the eastward‐flowing South Equatorial Counter Current (SECC) and the westward‐flowing South Equatorial Current (SEC), seems to play an important role in the performance of the longline fishery for albacore. Mesoscale eddy variability in the American Samoa Exclusive Economic Zone (EEZ) peaks from March to April, when the kinetic energy of the SECC is at its strongest. Longline albacore catch tends to be highest at the eddy edges, while albacore catch per effort (CPUE) shows intra‐annual variability with high CPUE that lags the periods of peak eddy activity by about 2 months. When CPUE is highest, the values are distributed toward the northern half of the EEZ, the region affected most by the SECC. Further indication of the possible importance of the SECC for longline performance is the significant drop in eddy variability in 2004 when compared with that observed in 2003 – resulting from a weak SECC – which was accompanied by a substantial drop in albacore CPUE rates and a lack of northward intensification of CPUE. From an ecosystem perspective, evidence to support higher micronekton biomass in the upper 200 m at eddy boundaries is inconclusive. Albacore's vertical distribution seems to be governed by the presence of prey. Albacore spend most of their time between 150 and 250 m, away from the deep daytime and shallow nighttime sonic scattering layers, at depths coinciding with those of small local maxima in micronekton biomass whose backscattering properties are consistent with those of albacore's preferred prey. Settling depths of longline sets during periods of decreased eddy activity correspond to those most occupied by albacore, possibly contributing to the lower CPUE by reducing catchability through rendering bait less attractive to albacore in the presence of prey. 相似文献