全文获取类型
收费全文 | 177篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
林业 | 22篇 |
农学 | 7篇 |
基础科学 | 3篇 |
8篇 | |
综合类 | 103篇 |
农作物 | 11篇 |
水产渔业 | 6篇 |
畜牧兽医 | 15篇 |
园艺 | 7篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 5篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 6篇 |
2007年 | 14篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 0 毫秒
91.
92.
20世纪初黑龙江省小麦生产的发展速度很快,种植面积较大,品质较好,小麦的贸易量也很大,但是单位面积的产量较低。同时,黑龙江省的小麦生产受到气象条件和病害以及国内外贸易的严重约束。20世纪初是黑龙江省小麦生产、贸易、加工快速发展的时期,成为我国主要的小麦产区。 相似文献
93.
C.S. Olsen 《Biological conservation》2005,125(4):505-514
There is a large annual international trade in the rhizomes of the alpine Himalayan perennials Nardostachys grandiflora DC. and Neopicrorhiza scrophulariiflora (Pennell) Hong, both species in a monotypic genus. This paper estimates the range of the annual trade levels and discusses the conservation implications. Data was collected through a nation-wide survey in Nepal using standardised open-ended interviews with 223 harvesters, 149 local traders, 90 central wholesalers, 53 regional wholesalers, and 16 processing industries. Data collection allowed cross-checking of findings by comparing an annual supply estimate and an annual consumption estimate. Regarding methodology, it is concluded that using agents’ own-reported values results in reliable volume and value estimates; however, validity should be treated with caution, as there is evidence of systematic bias in price reporting and underestimation of quantities. Trade data is thus evaluated to constitute conservative estimates, with local trader derived data being more valid than wholesaler derived data. Annual trade levels from Nepal are estimated at 100-500 tonnes of N. grandiflora rhizomes and 175-770 tonnes of N. scrophulariiflora rhizomes. In the case year of 1997/1998, the respective global amounts were estimated at 350-400 and 650-1000 tonnes (of which a maximum of 50-300 tonnes are from Picrorhiza kurrooa whose rhizomes are mixed with P. scrophulariiflora and traded under the name kutki) with a total CIF value of USD 2.7-3.6 million. Nepal is the main supplier (82 ± 5% of N. grandiflora and 66 ± 12 of kutki) followed by India (13 ± 5 and 19 ± 12) and Bhutan (5 ± 4 and 14 ± 8). The importance of applying a regional approach to conservation of the species is emphasised, as is the need for improved official trade monitoring by governments. 相似文献
94.
区域产业结构的变化对土地利用结构有决定性作用,从而对耕地质量保护形成决定性影响。尤其在我国进入WTO(the World Trade Organization)以及我国区域经济发展不平衡等大的社会经济背景下,我国产业升级将面临新的机遇与挑战,从而对我国耕地质量保护战略目标的实现形成强烈冲击。从总体上看,我国产业发展对耕地质量保护具有以下两个方面的影响:WTO框架下农业发展主要对农村生态环境和耕地质量保护的微观主体农户行为产生影响;WTO框架下非农产业发展一方面通过污染扩散、国际污染转移等方式直接影响到我国耕地质量;另一方面对农业发展和农户保护耕地行为产生影响,进而影响到我国耕地质量保护。为确定我国耕地质量变化与产业升级之间的关系,通过对WTO框架下我国产业升级对耕地质量影响分析,本文提出完善耕地质量保护的一些措施。 相似文献
95.
96.
97.
中国加入WTO,将对林业投资产生较大的影响,既存在机遇,也面临挑战。外资的引进无疑也会发生一定的变化,同时也将进一步促进中国企业优势项目的再投资。 相似文献
98.
The Fair Trade movement seeks to alter conventional trade relations through a system of social and environmental standards, certification, and labels designed to help shorten the social distance between consumers in the North and producers in the South. The strategy is based on working both in and against the same global capitalist market that it hopes to alter, raising questions about if and how Fair Trade initiatives exhibit counter-hegemonic potential to transform the conventional agro-food system. This paper considers the multiple levels at which Fair Trade alternatives operate to identify the different forms of social action that the movement engages with, and to clarify where the movements counter-hegemonic potentials are being realized. I suggest the Fair Trade movement is most successful in encouraging consumers and producers to commit acts of resistance and in supporting redistributive action that shifts resources from North to South. Up to now, however, Fair Trade alternatives appear to hold only a theoretical potential to provoke transformative change in the agro-food system. A reconceptualization of the Fair Trade model and how it is implemented could allow it to manifest more of its implicit, oppositional promise.Aimee Shreckis a sociologist and the Research Specialist for the California Faculty Association. Her previous work as a postdoctoral researcher with the University of California, Berkeley and the Sustainable Agriculture Research and Education Program focused on social justice, sustainable agriculture, and fair trade. 相似文献
99.
本文比较深入地分析了广东省东莞市鲜活农产品出口创汇的持续发展形势及面临的严峻挑战,从国际环境和自身条件,机遇和挑战的辨证关系上,论证了东莞市确立鲜活农产品以出口创汇为主的发展战略的必要性和可能性,提出了八项具体措施与对策,以实现扩展港澳市场,开拓东南亚和欧美等市场为目标。 相似文献
100.
Natalia Gomez 《山东饲料》2014,(5):215-216
China's growing participation in Latin American countries has been seen as a massive threat on the region 's manufacturing sector. Is it really this significant when it comes to its impact on manufacturing employment?With this project I pretend to examine the relationship between the bilateral commerce from China and Colombia in the textile a sector between the years 2000-2012. By examining the data I want to find out what is the correlation between jobs losses in Colombia's textile industry and the imports from China in the same industry.Analyzing the sector of textile is very significant to the country.It represents employment and production of added value products in an industry that has not only social impact but also historical meaning for the country. 相似文献