全文获取类型
收费全文 | 1141篇 |
免费 | 89篇 |
国内免费 | 13篇 |
专业分类
林业 | 43篇 |
农学 | 74篇 |
基础科学 | 65篇 |
87篇 | |
综合类 | 864篇 |
农作物 | 26篇 |
水产渔业 | 13篇 |
畜牧兽医 | 47篇 |
园艺 | 6篇 |
植物保护 | 18篇 |
出版年
2024年 | 1篇 |
2023年 | 29篇 |
2022年 | 48篇 |
2021年 | 41篇 |
2020年 | 58篇 |
2019年 | 30篇 |
2018年 | 23篇 |
2017年 | 51篇 |
2016年 | 60篇 |
2015年 | 50篇 |
2014年 | 98篇 |
2013年 | 128篇 |
2012年 | 132篇 |
2011年 | 117篇 |
2010年 | 78篇 |
2009年 | 83篇 |
2008年 | 58篇 |
2007年 | 43篇 |
2006年 | 49篇 |
2005年 | 27篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有1243条查询结果,搜索用时 78 毫秒
1.
为探究健康意识对规模养殖户以使用环保饲料为代表的亲环境行为的作用,以湖北省402个生猪规模养殖户为研究对象,应用Heckman两阶段模型,探讨健康意识对不同群体规模养殖户的影响差异。研究结果表明,大多数规模养殖户(78.97%)愿意为环保饲料付费,且平均意愿支付水平为每头生猪饲料成本的6.69%(46.80元·头-1)。健康意识中的健康关注程度对生猪规模养殖户环保饲料支付意愿具有正向促进作用,健康变化感知对其意愿支付水平的影响正向显著。通过主成分分析,健康意识整体上直接对规模养殖户环保饲料的支付意愿与意愿支付水平产生正向影响。而差异性分析也表明,在环保饲料支付意愿决策上,健康意识不同的规模养殖户群体间有明显差异。 相似文献
2.
在我国农业现代化、城镇化过程中,急需培育壮大新型农业经营主体,在农业领域创业的青年群体是其重要成员。通过对江苏地区农业领域青年创业现状的调查,归纳出在农业领域青年创业过程中普遍存在土地流转、资金、产品销售等方面的问题,并针对这些问题提出了优化农业创业环境的对策建议。 相似文献
3.
4.
为反映福建省高素质农民的发展状况,探索高素质农民培育的更有效途径,采用比较分析方法,跟踪调查2015—2018年福建省高素质农民的总量、性别比例、年龄结构、文化程度等数据,并以此为基础,重点分析农业新型经营主体家庭农场经营者、农民合作社负责人等群体的发展情况,同时比较研究福建省高素质农民重点群体之间的发展特点。从文化程度、培育供求、产学矛盾、政策扶持等方面深入剖析当前高素质农民发展的制约因素,从加快推进福建省高素质农民培育工作、构建高素质农民终身学习体系、探索培育新型农业经营模式、推进线上线下融合培育、创设高素质农民扶持政策等方面提出相应的对策建议。 相似文献
5.
基于我国9省小农户调查数据,运用双稳健的平均处理效应模型,研究了农地确权对小农户信贷可得性的影响及其作用机理。结果表明:农地确权可以提升小农户信贷可得性。进一步研究发现,需求方面的影响路径是:确权提高了小农户的土地安全性,增加了农业长期投资,并提高了信贷意愿。供给方面的影响路径是:确权增加了小农户的财产权并使其拥有了可流转大额财产,传递了还款可能性增加的信号;而且可将农地作为抵押品获得农地抵押贷款,增加了金融机构的贷款供给。不过,农地的信号传递作用大于抵押作用,农地抵押作用的发挥需要进行进一步的制度和组织创新。 相似文献
6.
J. O. Gusmão M. A. C. Danés D. R. Casagrande T. F. Bernardes 《Grass and Forage Science》2018,73(3):717-726
Alternatives need to be addressed for reducing losses in elephant grass (EG; Pennisetum purpureum) silages. Furthermore, smallholders lack information on the nutritional aspects of dairy farms. The aim of this study was to evaluate total mixed ration silage (TMR) combining fresh EG and concentrate ingredients, creating the following treatments: (i) EG silage (control); (ii) EG, corn and soya bean meal; (iii) EG, corn, soya bean meal and molasses; (iv) EG, citrus pulp and soya bean meal; and (v) EG, citrus pulp, soya bean meal and molasses. Five replicates of each treatment were ensiled in 15‐L plastic jars. The fermentation profile, chemical composition, microbial counts and aerobic stability were assessed. Three contrasts were tested, as follows: (i) control vs. TMR; (ii) TMR with corn vs. TMR with citrus pulp; and (iii) TMR with molasses vs. TMR without molasses. Variables were analysed through the PROC MIXED procedure of the SAS at the 5% level. The TMR had better fermentation profile, lower effluent production and longer aerobic stability compared to control. When the effect of corn was compared to citrus pulp among the TMR, silages with citrus pulp showed lower fermentation losses, non‐protein nitrogen and effluent production. The aerobic stability also improved with citrus pulp. Molasses did not affect the fermentation profile. Overall, lactic acid was the primary acid in all TMR. Nitrogen source (e.g., soya bean meal) can be used without compromising the fermentation process. TMR with citrus pulp showed better results than corn. TMR may be an alternative to optimize the use of EG on smallholdings. 相似文献
7.
[目的]探讨陕西省"三农"融合发展路径,并揭示生态—社会—环境系统变迁对"三农"融合发展的影响,为实现建设"富裕陕西""和谐陕西"及"美丽陕西"的目标服务。[方法]通过实地调研与文献研究,分析生态—社会—环境系统变迁与"三农"融合发展的关联性及趋势。[结果]"三农"融合发展路径沿着消费结构→产业结构→职业结构→收入结构→阶层结构→社会结构的脉络依次展开。影响陕西省"三农"融合发展的压力在于"三农"割裂式发展形成相互牵制的循环圈,以及滞后于经济社会总进程的"三农"发展和生态保育;"三农"融合发展的潜力源自"三农"自身及变革中的生态—社会—环境系统;促使"三农"兼容和协调发展的5大动力分别是:国家作用、市场力量、组织角色、职业农民和生态环境。[结论]为了保证陕西省"三农"融合发展路径的顺畅,应从顶层设计、内涵发展和协同视角三方面,进一步健全与完善生态—社会—环境系统。 相似文献
8.
Celia Barbero-Sierra Manuel Ruíz Pérez María José Marqués Pérez Ana María Álvarez González José Luis Cruz Maceín 《Arid Land Research and Management》2018,32(1):111-129
Farmers’ land management is a key factor for sustainable agriculture, yet the traditional knowledge which constitutes its base is seldom incorporated in the land and soil academic literature. The need for a hybrid approach that combines local (farmers’) and scientific knowledge is formally recognized. Plot quality criteria are a component of both sources of knowledge, playing an important role in shaping land management practices. Yet there are few case studies comparing the criteria used by farmers and soil scientists when assessing plot quality, particularly in developed countries. We compare the plot quality assessment done by a sample of 31 farmers in a semiarid area of Spain with an edaphic quality index (EQI) obtained through laboratory analyses of soil samples from 61 farm plots. There is a coincidence between farmer and laboratory assessments in 70% of cases. Plots identified by farmers as being of good quality have a significantly higher EQI than those identified as bad quality. The two key differentiating parameters were clay content (average 21% in good versus 18% in bad quality plots) and soil organic carbon content (1.6 and 1.3%, respectively), both closely related to soil water retention ability. A holistic land vision, a higher level of education and large differences in EQI between good and bad plots as assessed by farmers have a positive influence in the degree of coincidence between farmers’ and laboratory assessments. 相似文献
9.
Justice A. Tambo Roger K. Day Julien Lamontagne-Godwin Silvia Silvestri Patrick K. Beseh Birgitta Oppong-Mensah 《国际虫害防治杂志》2020,66(4):298-310
AbstractSince its emergence in Africa in 2016, fall armyworm (FAW) has spread rapidly and poses a severe threat to the food security and livelihood of millions of smallholder farmers in the continent. Using survey data from Ghana and Zambia, we examined FAW prevention and control methods implemented by farm households and their impacts on maize output and household consumption of self-produced maize. The main control methods used included pesticide application and handpicking of larvae, while access to information on FAW was a key driver behind the implementation of the control methods. Results from an endogenous switching regression showed that the implementation of a FAW management strategy significantly enhanced maize yield and households’ own maize consumption. When disentangling the impacts of the main control methods, we found that the combination of pesticide application and handpicking of larvae produced the highest yield gain of 125%. We concluded that the current interventions put in place by farmers to tackle FAW infestations are providing positive outcomes, but successful management of the pest will require more actions, including raising awareness to enhance the adoption of control interventions and exploring other control options. 相似文献
10.