全文获取类型
收费全文 | 792篇 |
免费 | 27篇 |
国内免费 | 26篇 |
专业分类
林业 | 105篇 |
农学 | 81篇 |
基础科学 | 71篇 |
46篇 | |
综合类 | 469篇 |
农作物 | 12篇 |
水产渔业 | 23篇 |
畜牧兽医 | 21篇 |
园艺 | 6篇 |
植物保护 | 11篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 24篇 |
2018年 | 5篇 |
2017年 | 15篇 |
2016年 | 22篇 |
2015年 | 26篇 |
2014年 | 52篇 |
2013年 | 41篇 |
2012年 | 62篇 |
2011年 | 49篇 |
2010年 | 46篇 |
2009年 | 43篇 |
2008年 | 48篇 |
2007年 | 69篇 |
2006年 | 48篇 |
2005年 | 49篇 |
2004年 | 37篇 |
2003年 | 27篇 |
2002年 | 33篇 |
2001年 | 20篇 |
2000年 | 13篇 |
1999年 | 17篇 |
1998年 | 15篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
排序方式: 共有845条查询结果,搜索用时 15 毫秒
22.
适应投资体制改革规范林业工程咨询成果 总被引:2,自引:0,他引:2
为适应我国投资体制改革,规范林业工程咨询成果,本文总结了林业工程咨询成果中存在的问题,并对林业工程咨询从业人员提出了建议。 相似文献
23.
24.
25.
The focus of foreign direct investment (FDI) in the global forest sector has shifted from developed to developing economies (currently accounting 73% of total) during the past two decades. China has been the main global driver with its annual FDI soaring from USD 130 million in 2002 to USD 550 million in 2010. In light of international economic and business theories, choice of foreign entry mode is considered the most critical issue in corporate expansion strategy, which, however, has not been empirically studied in the forest sector. To fill this gap, our paper focuses on modeling two equity-based entry mode choices (i.e. wholly owned subsidiary or joint ventures) of foreign investment projects in China based on data from 109 activities of the Top 100 forest, paper, and packaging industry companies. By using logistic modeling, the main determinants of corporate entry mode choice are found to be cultural and geographical distance between the corporate home country and China, duration of corporate presence in China, and spatial concentration of local-level forest industry. Instead, investment project size and local resource availability are found to have no significant impact on corporate entry mode choice in China. 相似文献
26.
Analysis on Unbalance of Real Estate Investment Goal under the Environment of High Profit Margin 下载免费PDF全文
With incessant development of Chinese real estate market, the amount and size of real estate corporations are enlarging rapidly and the real estate corporation investment goal is tending to become divertive. So it is especially important to understand rightly the investment goal of the real estate corporations. This paper analyzes the unbalance phenomena of real estate corporation investment under the environment of high profit margin and discusses the serious aftereffect from this unbalance. Finally this paper brings forward the right order of investment goals for the real estate corporations in order to contribute to a nicer performance of real estate corporations in establishing sustainable development stratagem. 相似文献
27.
According to analyses of the existing problems in the evaluation of agent of government investment project, combining with the characters of the substituted construction system of the government invested project and the project management, a performance evaluation index system of the agent of government invested project was constructed, fdlowing the basic principles of the index settlement. It introduces the AHP, the fuzzy evaluation mode, and the ADF comprehensive evaluation mode based on DEA, and gives some practical examples. 相似文献
28.
给水管线造价公式的精确性对工程经济分析与给水管网优化的科学性和经济性有重大影响。通过五个地区的铸铁管综合单价数据,采用最小二乘法对各组数据进行多项式一至十次的拟合,确定了给水管线造价公式的最佳拟合次数为三次;进一步采用模拟退火算法对拟合的多项式参数进行优化计算,求解给水管线造价公式。结果表明:凭借模拟退火算法随机全局搜索模式以及不受函数性质影响的优势,能够克服传统算法难以求解多阶导数的困难,提高公式拟合精度。 相似文献
29.
30.