全文获取类型
收费全文 | 654篇 |
免费 | 48篇 |
国内免费 | 48篇 |
专业分类
林业 | 14篇 |
农学 | 48篇 |
基础科学 | 3篇 |
66篇 | |
综合类 | 241篇 |
农作物 | 42篇 |
水产渔业 | 124篇 |
畜牧兽医 | 184篇 |
园艺 | 13篇 |
植物保护 | 15篇 |
出版年
2024年 | 4篇 |
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 20篇 |
2020年 | 18篇 |
2019年 | 27篇 |
2018年 | 18篇 |
2017年 | 28篇 |
2016年 | 25篇 |
2015年 | 25篇 |
2014年 | 28篇 |
2013年 | 50篇 |
2012年 | 57篇 |
2011年 | 57篇 |
2010年 | 50篇 |
2009年 | 41篇 |
2008年 | 29篇 |
2007年 | 38篇 |
2006年 | 33篇 |
2005年 | 30篇 |
2004年 | 19篇 |
2003年 | 21篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1984年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有750条查询结果,搜索用时 15 毫秒
111.
P.W. Greig-Smith H.M. Thompson A.R. Hardy M.H. Bew E. Findlay J.H. Stevenson 《Crop Protection》1994,13(8):567-581
Suspected cases of poisoning of honeybees by agricultural pesticides are investigated by the Ministry of Agriculture, Fisheries and Food (in England and Wales) and the Scottish Office Agriculture and Fisheries Department (in Scotland). Studies include field visits to sites where bee mortality is recorded, examination of dead bees for disease, and analysis for the presence of pesticide residues. This paper reviews the results of these investigations for the period 1981–1991. Pesticide poisoning is diagnosed from the detection of residues in dead bees, through interpretation in relation to the median lethal dose (LD50), and ‘subsequent residue level’ (SRL) determined from laboratory studies in which bees were exposed to one LD50 dose. Overall, an annual average of 50 incidents were confirmed as due to pesticide poisoning, involving 30 pesticide active ingredients during the 1981–1991 period. In England and Wales, the principal hazards were caused by misuse of the insecticide triazophos on oilseed rape, a problem that has been reduced to low levels during the 1980s, and by dimethoate use on a variety of arable crops. In Scotland there were fewer incidents, most of which were associated with use of fenitrothion on raspberries, and gamma-HCH on oilseed rape. Opportunities for reducing the risks of poisoning, and for refining the investigation of suspected incidents, are discussed. 相似文献
112.
1前言湖南省洞口县第二例牛尿素中毒,制做了简易竹洞针,进行左赚部套洞针(竹洞针)穿刺术放气,灌入食醋,葡萄糖输液等抢救和治疗方案。牛场存栏328头,239头中毒,发病率72.9%,治疗239头,治愈216头,治愈率90.4%,较首例牛尿素中毒病例治愈率100%,降低9.6个百分点,瘤胃膨气病病牛128头,治愈105头,治愈率82.0%,较洞口县首例牛尿素中毒病例治愈率100%,下降18.0个百分点;并对牛瘤胃膨气病最佳抢救时间和尿素养牛正确用量用法进行了探索,供同行参考。 相似文献
113.
The influence of elevated levels of micronutrients on the growth and flowering of French marigold (Tagetes patula L.) was investigated. Plants were grown with nutrient solution containing 0.25, 0.5, 1, 2, 3, 4, 5, or 6 mM boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), or zinc (Zn) and toxicity development was monitored. The threshold micronutrient concentrations that induced visible foliar toxicity symptoms were 0.5 mM B, 4 mM Cu, 4 mM Fe, 2 mM Mn, 1 mM Mo, and 5 mM Zn. The dry matter yields during the 5 week experimental period were reduced when micronutrient concentrations exceeded 0.5 mM B, 3 mM Cu, 3 mM Fe, 6 mM Mn, 0.5 mM Mo, and 5 mM Zn in the fertilizer solution. Leaf chlorophyll contents decreased when the nutrient solution concentrations of Cu, Fe, and Mn were greater than 0.5 mM, 3 mM, and 2 mM, respectively. Visual toxicity symptoms of the six micronutrients were characterized. 相似文献
114.
115.
苯甲酸钠对土壤亚硝酸还原酶动力学参数的影响 总被引:1,自引:0,他引:1
采用改进的α-荼胺-对氨基苯磺酸比色法研究了苯甲酸钠对紫色土亚硝酸还原酶动力学参数的影响。结果表明,苯甲酸钠对灰棕紫泥土亚硝酸还原酶酶促反应的抑制能力随苯甲酸钠浓度的增大而增强,苯甲酸钠的加入,降低了V0、Km和Vmax值,表明苯甲酸钠对土壤亚硝酸还原酶的作用类型表现为反竞争性抑制作用;苯甲酸钠是一种优良的反硝化抑制剂,有良好的应用前景。 相似文献
116.
镉对水稻等作物的毒害作用 总被引:1,自引:0,他引:1
简单介绍镉对动物体的毒害机理和中毒病症。着重分析了镉对作物体的毒害,其中包括生物化学机理,对水稻和蔬菜等作物的毒害原理、程度、差异及后果。还阐明了与其他元素互作的毒害作用。从而,明确研究镉污染土壤的理论和现实意义,为防止镉进入食物链找到了有力的依据。 相似文献
117.
118.
Melissa A. Friedman Lora E. Fleming Mercedes Fernandez Paul Bienfang Kathleen Schrank Robert Dickey Marie-Yasmine Bottein Lorraine Backer Ram Ayyar Richard Weisman Sharon Watkins Ray Granade Andrew Reich 《Marine drugs》2008,6(3):456-479
Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world, and it causes substantial physical and functional impact. It produces a myriad of gastrointestinal, neurologic and/or cardiovascular symptoms which last days to weeks, or even months. Although there are reports of symptom amelioration with some interventions (e.g. IV mannitol), the appropriate treatment for CFP remains unclear to many physicians. We review the literature on the treatments for CFP, including randomized controlled studies and anecdotal reports. The article is intended to clarify treatment options, and provide information about management and prevention of CFP, for emergency room physicians, poison control information providers, other health care providers, and patients. 相似文献
119.
本试验是工厂化养鱼实用技术模式研究项目中的一个方面。试验于2002年5月24日至7月25日进行,养殖品种为奥尼罗非鱼和短盖巨脂鲤(亦名淡水白鲳)。初始放鱼量40.0kg/m^3,实验结束时单位水体鱼获量奥尼罗非鱼为78.2kg/m^3,淡水白鲳为82.2kg/m^3。试验期间每两天化验一次,共化验32次,监测8项水质理化指标的变化范围分别为:水温22-30℃、pH值7.36~8.28、溶解氧1.17~8.51mg/L、氨氮0.79~11.27mg/L、亚硝酸氮0.551~8.520mg/L、硝酸氮3.33-42.79mg/L、磷酸盐磷0.547-9.230mg/L、碱度257.2-358.2mg/L。 相似文献
120.