全文获取类型
收费全文 | 11769篇 |
免费 | 694篇 |
国内免费 | 1372篇 |
专业分类
林业 | 1268篇 |
农学 | 1601篇 |
基础科学 | 712篇 |
1540篇 | |
综合类 | 4237篇 |
农作物 | 934篇 |
水产渔业 | 599篇 |
畜牧兽医 | 1815篇 |
园艺 | 439篇 |
植物保护 | 690篇 |
出版年
2024年 | 47篇 |
2023年 | 181篇 |
2022年 | 393篇 |
2021年 | 480篇 |
2020年 | 519篇 |
2019年 | 491篇 |
2018年 | 296篇 |
2017年 | 445篇 |
2016年 | 420篇 |
2015年 | 540篇 |
2014年 | 616篇 |
2013年 | 633篇 |
2012年 | 754篇 |
2011年 | 827篇 |
2010年 | 773篇 |
2009年 | 667篇 |
2008年 | 580篇 |
2007年 | 485篇 |
2006年 | 469篇 |
2005年 | 475篇 |
2004年 | 302篇 |
2003年 | 436篇 |
2002年 | 709篇 |
2001年 | 571篇 |
2000年 | 397篇 |
1999年 | 248篇 |
1998年 | 175篇 |
1997年 | 137篇 |
1996年 | 123篇 |
1995年 | 106篇 |
1994年 | 73篇 |
1993年 | 83篇 |
1992年 | 97篇 |
1991年 | 78篇 |
1990年 | 64篇 |
1989年 | 48篇 |
1988年 | 31篇 |
1987年 | 22篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1962年 | 2篇 |
1956年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
141.
The traditional scheduling for vehicle is option in the fixed network. But it can't satisfy the real time environment. The demand of order is changeable and uncertain in real environment. It is convenient for scheduling transforming it into static data, but can't get the advantage on time. This paper proposes a real time vehicle scheduling on the study of traditional scheduling and discusses the model structure and the key technology for the real time system that establishes the base for develop teal time system. 相似文献
142.
Information integrating is the most important key to CIMS,which is the base of the function integrating and all others.Because of so many kinds,so complicated structure,so many different sources and uses that the information in CIMS has,it is necessary to build a popular Information Integrating Model. The model of information integrating in the thesis bases on the enterprise model,which is presented by ISO(International Organization for Standardization).According to the object-oriented method,the process of modeling begins with classifying the information,and then describes the definition of the attributes and the structural relation of those objects. By means of the idea of Encapsulation and Inheritance,the destination of information integrating can be arrive and the model of information integrating can be set up. The model which is based on the share information is helpful to finish the function integrating and the whole CIMS' construction. Moreover,the system which is developed following such program can be reused for many times and the developing circle of CIMS can be apparently shortened,too. 相似文献
143.
Based on analyzing about blasting mode of slope in the construction of road, the paper shows that pre splitting blasting is mostly suitable in the section of severely weathering soft rock with developed joints and fractures, introduced the laying out about the hole of pre splitting blasting that can apply in the high slope of the expressway in the section, and designed the parameter. The practice shows that it gained favourable effect by this method. 相似文献
144.
It has been briefly studied and reported that Actinidia chinensis , one of economic woody plants, has been bred with the method of plant tissue culture. Aim at the shortage of traditional plant tissue culture ways which ignored the refinement and transplant of test-tube seedling, it strengthen the study to breeding and management of Actinidia chinensis seedlings before they grow up and become mature seedlings. Through our explore, the transplant survive rate of tissue-culture seedlings attain to about 85%.This study is the improvement to traditional breeding seedling means and it is helpful to the rapid propagation of those economic woody plants. 相似文献
145.
This paper investigates the coordinated operation of the progress planning with the resource planning when carrying out engineering projects and puts forward a method of "RSM" under the resource limit conditions. Then, the "RSM" was improved to avoid complicated calculation. This method not only reduces the calculating work by hand but saves computer's memory as well, making the time-resource optimization work more quick and convenient. 相似文献
146.
147.
Xiao Weipin 《保鲜与加工》1994,(1)
This paper presents some problems that is important part of the desision supportsystem on science-technic progress management at the construction enterprise and discusses targetsystems and evaluation models of synthesis effects on science-technic grogress at the sonstruction en-terprise,and some problem are illustrated and analysed further. 相似文献
148.
Cai Shaoxi Wu Xi Xiao Jun Liu Yanhai Wu Yunpeng 《保鲜与加工》1992,(3):15-18
This paper describes a part of the experiments concerning the viscoelasticity of human blood, which are based upon the theories lead by the authors. The data from the experiments are compared with those in the literatures. The effect of cell hematocrit on viscoelasticity is especially discussed and a new viscoelasticity index is defined to eliminate this effect. 相似文献
149.
150.
This paper presents the end-effect factor of Synchronous motor with cylindricalsolid rotor offered by analysing the 3-D electromagnetic field and using the Poynting vector.To ap-ply it in an actual calculation,the end-effect factor is proved correct and applicable. 相似文献