全文获取类型
收费全文 | 5205篇 |
免费 | 456篇 |
国内免费 | 213篇 |
专业分类
林业 | 980篇 |
农学 | 299篇 |
基础科学 | 322篇 |
999篇 | |
综合类 | 2079篇 |
农作物 | 38篇 |
水产渔业 | 520篇 |
畜牧兽医 | 165篇 |
园艺 | 142篇 |
植物保护 | 330篇 |
出版年
2024年 | 20篇 |
2023年 | 90篇 |
2022年 | 113篇 |
2021年 | 164篇 |
2020年 | 161篇 |
2019年 | 191篇 |
2018年 | 122篇 |
2017年 | 227篇 |
2016年 | 216篇 |
2015年 | 218篇 |
2014年 | 323篇 |
2013年 | 372篇 |
2012年 | 573篇 |
2011年 | 490篇 |
2010年 | 343篇 |
2009年 | 346篇 |
2008年 | 296篇 |
2007年 | 314篇 |
2006年 | 306篇 |
2005年 | 212篇 |
2004年 | 175篇 |
2003年 | 124篇 |
2002年 | 86篇 |
2001年 | 73篇 |
2000年 | 75篇 |
1999年 | 56篇 |
1998年 | 47篇 |
1997年 | 39篇 |
1996年 | 14篇 |
1995年 | 21篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 1篇 |
1986年 | 2篇 |
排序方式: 共有5874条查询结果,搜索用时 453 毫秒
41.
42.
In urban design, only by continuous and dynamic research work from design to finally putting it into practice, can we made good control on city appearance. This article analyzes nowadays defects in our urban design from two aspects as the result establishment and validated control, and tries to conceive a feasibility plan to solve the problem. 相似文献
43.
The management of urban reconstruction is a process of game between the government and developers.It is helpful that the interest and its equilibrium for the relative parties involved in the reconstruction process are considered during the formation of government policy.This paper analyzes the environment for the policy constitution and establishes a model for strategy making based on the game theory.This model provides a basic foundation to improve the management ability of the government in the reconstruction process.Finally,in this paper some strategic issues are suggested to cope with the challenges from urban reconstruction in China. 相似文献
44.
Today the information globalization is the trend of society development. The information technology has great influence not only on the mode of life and production, but also on the urban social and economic structure. In order to fit in with the change in this regard, the urban land-use distribution, residential mode, traffic pattern and so on should be changed correspondingly. Therefore, this change will lead to the development and evolution of whole urban spatial structure. In this paper, the development tendency of urban spatial structure in the information age is analyzed and some proposals on city planning and construction are put forward. 相似文献
45.
ZHOU Hua-jun 《保鲜与加工》2001,(5):1
Hydrodynamic models have been widely applied to river and coastal engineering projects. Understanding the hydrodynamic process is a prerequisite to modeling the pollution and sediment transport process. Hydrodynamic models of varying degrees of complexity should be selected appropriately according to the object of study, physical properties of the flow domain and hydrodynamic features. The essential procedure of hydrodynamic simulation is described in this paper. The main problems such as selection of model dimension in physical space, choice of variables, boundary conditions, initialization, design of computational grid, model resolution, parameterization of smaller scale fluctuations and sub-grid scale processes, model calibration and verification are investigated. 相似文献
46.
The thesis introduces the origin of demonstrate item on the city water environment quality improvement-tao-hua river water environment competitive administer, analyzes the current situation and cause of taohua river valley pollute and ecological destroy, and summarizes the gain and loss in projects which have taken place in the domestic city water environment competitive administer. On the base, a collectivity idea is put forward that it should stress recovering and rebuilding ecosystem on the item. Due to the water environment in taohua river is representative, if the item can be favorably carried out, it not only improves GuiLin water environment, makes people life advantage and expands city tour, but also produces important affects to the other domestic cities in the condition of using marketable economy means to improve city water environment quality. 相似文献
47.
The conservation of historic buildings and their environment is an unavoidable problem in urban construction. In this paper, the authors give a few new thoughts about the problem. First, the historic buildings are important part of the core power in city competition.Second,the conservation work should be combined with their development. Third, a classified and multilevel system of protection and reuse of old buildings should be set up. 相似文献
48.
The policy of public participation in urban planning was first practiced in Europe in the 1960s. After 40 years of development, the policy has become the essential step of city planning in Western countries where as is just at the elementary step in China. For the purpose of knowing the situation about the policy performing in local cities and discussing the feasibility of public participation in urban planning, several kinds of investigation have been done. From the investigation, it is found that although the public participation has already been the important step of urban planning in some city during just several years,there are still many problems. This paper shows a panorama view of this issue. Th describe the future of public participation in e authors will offer some solutions according to the problems and the urban planning. 相似文献
49.
50.