全文获取类型
收费全文 | 4441篇 |
免费 | 269篇 |
国内免费 | 385篇 |
专业分类
林业 | 324篇 |
农学 | 299篇 |
基础科学 | 322篇 |
552篇 | |
综合类 | 2166篇 |
农作物 | 176篇 |
水产渔业 | 324篇 |
畜牧兽医 | 594篇 |
园艺 | 71篇 |
植物保护 | 267篇 |
出版年
2024年 | 23篇 |
2023年 | 100篇 |
2022年 | 150篇 |
2021年 | 168篇 |
2020年 | 155篇 |
2019年 | 166篇 |
2018年 | 99篇 |
2017年 | 222篇 |
2016年 | 243篇 |
2015年 | 246篇 |
2014年 | 224篇 |
2013年 | 317篇 |
2012年 | 363篇 |
2011年 | 362篇 |
2010年 | 270篇 |
2009年 | 243篇 |
2008年 | 222篇 |
2007年 | 251篇 |
2006年 | 245篇 |
2005年 | 161篇 |
2004年 | 137篇 |
2003年 | 105篇 |
2002年 | 95篇 |
2001年 | 80篇 |
2000年 | 61篇 |
1999年 | 46篇 |
1998年 | 42篇 |
1997年 | 42篇 |
1996年 | 30篇 |
1995年 | 36篇 |
1994年 | 26篇 |
1993年 | 20篇 |
1992年 | 32篇 |
1991年 | 45篇 |
1990年 | 25篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有5095条查询结果,搜索用时 31 毫秒
81.
This paper analyzes the limitation of regarding the weighted average cost of capital as the optimal standard of capital structure in the traditional capital structure decision-making method, and analyzes the view that the capital structure is affected by many factors,such as earning power, long-term stability of operating, the attitudes held by owners and operators, the attitudes held by creditors and financial risk. With the example, the affecting factors of the capital structure is analyzed. The fuzzy synthetic evaluation model are employed to decision-making of the capital structure. This article also shows the key point of its application. 相似文献
82.
83.
In accordance with the special characteristics of state medium-sized construction enterprises and their reform objects of "having a free hand and enlivening", the suitable objective model, the stock cooperative system for state medium-sized construction enterprises has been put forward in this paper by analyzing the system mechanism of stock cooperative system enterprises. Then the causes for it were expounded. 相似文献
84.
The externality of surrounding is introduced into the 2-capital of economical increasing models, which includes human factors, to explore the influences of circumstances contradiction on the human capital formation. The normal and special nash equilibrium of environmental and human capital is presented through a limited boundary model of overlapping generations. The character of equilibrium trail and its economical meaning are examined. The study on the model shows that laissez faire economy will be either stagnant,growing,or collapsing in the long-run,depending on the returns of the learning technology with respect to the two kinds of capital,the initial state of economy,and the relative price of the environmental and consumption goods. 相似文献
85.
The relationship of investors and venture capitalists is an important part in venture capital. Based on asymmetric information, this paper analyzes the principal agent relationship between investors and venture capitalists with game theory. And this paper mainly discusses the choosing, controlling and incentive problem. It suggests that only the capable and self confident venture capitalists could accept the terms of the limited partnership. It also indicates that recompense mechanism which holds the interest of investors and that of venture capitalists tightly is the center of the limited partnership. Rate of yield is the key of recompense mechanism, it not only reflects the incentive on venture capitalists, also reflects the share of risk between investors and venture capitalists. At last, the market credit play an important role in venture capital. 相似文献
87.
The implement of enterprise knowledge management gives rise to extensive research on its measurement. Based on the existing measurement theories and evaluation index systems of enterprise knowledge management during the past three years in China, this paper analyzes the problems in measuring target and designing the evaluation index system in the existing research findings, and explains detailedly why measurement target of enterprise knowledge management should be "level evaluation" instead of "performance evaluation", and definitely points out the meanings of enterprise knowledge management level and significance of its evaluation. This paper also indicates that the design of the evaluation index system should be complete, reasonable, proper and operable. 相似文献
88.
89.
It is important for enterprises' inventory management to find out the optimal production cycle and the length of shortage time,so that the total cost of inventory system can be reduced and the service level can be raised.Based on the classical EPQ model,this paper develops an EPQ model for deterioration items with different lost sale factor relative to the inventory level during shortage period.The existence of unique optimal solution is discussed by mathematic analysis and a numeric example.The sensitivity analysis shows that the parameter of losing sale has different impact on the costs of inventory system.The factors must be considered for the production inventory system to make management decision. 相似文献
90.
The quality of service provided by the provincial Irrigation Department (DGI) to the Water Users Associations (UA), and subsequently by the UA's to the related water users, is based on the provincial water law. The intended volume of water being delivered per considered period further depends on the water availability and on the (crop irrigation) water requirements. The Service Level (SL) compares the intended water supply with the water supply that would be required to supply the entire irrigable area with sufficient water. As soon as the intended water delivery pattern is set, the measured actual delivery can be assessed against the intention. Several performance indicators are used in this context. Based on the assessment of the Water Delivery Performance Ratio and the Overall Consumed Ratio recommendations are made on changes which can be made to improve water use and reduce problems of waterlogging. 相似文献