全文获取类型
收费全文 | 79080篇 |
免费 | 4532篇 |
国内免费 | 5552篇 |
专业分类
林业 | 9386篇 |
农学 | 5823篇 |
基础科学 | 4181篇 |
10705篇 | |
综合类 | 39544篇 |
农作物 | 3268篇 |
水产渔业 | 2826篇 |
畜牧兽医 | 7283篇 |
园艺 | 2018篇 |
植物保护 | 4130篇 |
出版年
2024年 | 275篇 |
2023年 | 1113篇 |
2022年 | 1645篇 |
2021年 | 1829篇 |
2020年 | 1879篇 |
2019年 | 2288篇 |
2018年 | 1281篇 |
2017年 | 2337篇 |
2016年 | 2913篇 |
2015年 | 2653篇 |
2014年 | 3714篇 |
2013年 | 3814篇 |
2012年 | 5709篇 |
2011年 | 6048篇 |
2010年 | 4950篇 |
2009年 | 4965篇 |
2008年 | 4599篇 |
2007年 | 5571篇 |
2006年 | 4901篇 |
2005年 | 4117篇 |
2004年 | 3140篇 |
2003年 | 2740篇 |
2002年 | 2125篇 |
2001年 | 1852篇 |
2000年 | 1708篇 |
1999年 | 1338篇 |
1998年 | 1170篇 |
1997年 | 1043篇 |
1996年 | 1021篇 |
1995年 | 1014篇 |
1994年 | 969篇 |
1993年 | 834篇 |
1992年 | 773篇 |
1991年 | 651篇 |
1990年 | 586篇 |
1989年 | 528篇 |
1988年 | 413篇 |
1987年 | 282篇 |
1986年 | 135篇 |
1985年 | 47篇 |
1984年 | 28篇 |
1983年 | 23篇 |
1982年 | 23篇 |
1981年 | 20篇 |
1980年 | 24篇 |
1979年 | 17篇 |
1978年 | 18篇 |
1977年 | 7篇 |
1976年 | 11篇 |
1962年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
The effective competition is an effective organizational form of the industry in modem market economy. It is a form accompanied with large - scale production and vigor competition. The analysis of effective competition has been the focus that people have paid close attention to it very much all the time. It is a basis of industrial policy, on the basis of the former research, the aufhors bring out 9 indexes according to the actual situation of our country, then take automobile trade as an example, we analyze the automobile trade with principal component. 相似文献
992.
This paper summarized the recent research results about the durability of structures, introduced their current application in durability design, appraisal, estimation of rest life and strategy of maintenance and strengthening as well as in other fields. 相似文献
993.
994.
Philosophy of science led by Popper is one of the most important contemporary scientific and philosophic theories.In addition to the science,the philosophy of science impacted contemporary social science mostly,of which the false-feasibility,circumstantial logic,anti-historical determinism and anti-scientism influenced the orientation of contemporary architecture.Just with these factors of philosophy of science,this thesis reanalyzed and reviewed Chinese contemporary architectural forms,especially the tradition inheritance. 相似文献
995.
996.
997.
998.
999.
1000.
Valuation based on the bill of quantifies will change the existing valuation mode of tender and bidding. For the standardized management of tender and bidding for power projects and the inteUigentized information management of power enterprises, it is an inevitable trend of reform to apply the valuation mode based on the bill of quantifies. According to the characteristics of power projects, this paper expounds the working process of the valuation mode based on the bill of quantities and analyzes the goal and function need of the tender and bidding management system. Considering the calculation procedure of the valuation and the quote strategy of quantities bill, the composition of fees for the valuation is settled and the calculation method is designed. To establish the management system of tender and bidding with a valuation based on the bill of quantities is beneficial for the costing reform of power projects and the perfection of the tender and bidding market. Therefore it is of great significance to spread the new management mode of project costing with a valuation based on the bill of quantities. 相似文献