全文获取类型
收费全文 | 15256篇 |
免费 | 416篇 |
国内免费 | 4篇 |
专业分类
财政金融 | 2355篇 |
工业经济 | 1099篇 |
计划管理 | 2148篇 |
经济学 | 2822篇 |
综合类 | 181篇 |
运输经济 | 93篇 |
旅游经济 | 188篇 |
贸易经济 | 2167篇 |
农业经济 | 659篇 |
经济概况 | 1474篇 |
水利工程 | 2483篇 |
信息产业经济 | 1篇 |
邮电经济 | 6篇 |
出版年
2021年 | 120篇 |
2020年 | 163篇 |
2019年 | 220篇 |
2018年 | 301篇 |
2017年 | 306篇 |
2016年 | 320篇 |
2015年 | 208篇 |
2014年 | 292篇 |
2013年 | 1352篇 |
2012年 | 499篇 |
2011年 | 527篇 |
2010年 | 402篇 |
2009年 | 454篇 |
2008年 | 417篇 |
2007年 | 555篇 |
2006年 | 464篇 |
2005年 | 355篇 |
2004年 | 383篇 |
2003年 | 274篇 |
2002年 | 314篇 |
2001年 | 284篇 |
2000年 | 293篇 |
1999年 | 242篇 |
1998年 | 257篇 |
1997年 | 260篇 |
1996年 | 245篇 |
1995年 | 221篇 |
1994年 | 229篇 |
1993年 | 222篇 |
1992年 | 277篇 |
1991年 | 256篇 |
1990年 | 218篇 |
1989年 | 182篇 |
1988年 | 183篇 |
1987年 | 210篇 |
1986年 | 208篇 |
1985年 | 289篇 |
1984年 | 305篇 |
1983年 | 285篇 |
1982年 | 257篇 |
1981年 | 262篇 |
1980年 | 249篇 |
1979年 | 257篇 |
1978年 | 188篇 |
1977年 | 163篇 |
1976年 | 131篇 |
1975年 | 145篇 |
1974年 | 120篇 |
1973年 | 113篇 |
1971年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
141.
142.
143.
Ronald D. Anderson Roger E. Jerman James A. Constantin 《Industrial Marketing Management》1978,7(1):60-64
The study in this article involved the investigation of 15 carrier selection variables over three dimensions by three groups with high involvement in the purchasing decision—traffic managers, sales representatives, and sales managers. The primary focus of the study was the identification of significant differences in the assessment of importance of the technical abilities of a carrier, the service orientation of a carrier and the image of a carrier as perceived by sales managers and sales representatives representing the selling systems, and traffic managers representing the buying systems. 相似文献
144.
145.
Based on data obtained from 359 idea evaluators, canonical correlation analysis was used to examine the relationship between several organizational factors and a set of criteria used in the evaluation of technical ideas. In contrast to other studies, it was found that organizational factors—assessed in terms of organizational climate—could be explained in terms of two dimensions: organizational clarity and risk. Technical evaluation criteria could be explained in terms of professional self-gratification and organizational responsibility. In light of the multivariate relationship among the two sets of factors, a number of organizational design implications are outlined. 相似文献
146.
147.
148.
Abstract Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immediate children and what we can only guess our yet-to-be-born descendants may wish us to do, or not do, for them in some distant future. This task must involve professionals from other disciplines in a context much broader than just water management. Once these impacts and tradeoffs are identified, it is then up to the political process to make choices when they are in conflict. All of us need to be a part of this decision-making process. 相似文献
149.
E. Slawczo Denczew 《国际水》2013,38(3):448-450
150.
In order to extract intracellular lipids from cyanobacterial Synechocystis PCC 6803 for biofuel production, seven cell-disruption methods - autoclaving, bead beating, freeze drying, French press, microwave, pulsed electric fields (PEF), and ultrasound - were tested prior to lipid extraction to make intracellular lipids more accessible by organic solvents. The different methods brought about distinct disruption effects to the cell envelope, plasma membrane, and thylakoid membranes that were related to extraction efficiency. Microwave, PEF, and ultrasound with temperature control had significant enhancement of lipid extraction (9-13% increases). Bead beating, freeze drying, and French press did not provide significant enhancement of lipid extraction. Furthermore, autoclaving, French press, and ultrasound treatments caused significant release of lipid into the medium, which may increase solvent usage and make medium recycling difficult. In order to minimize the cost of cell-disruption and lipid-extraction steps, microwave and PEF (with temperature control) might be best suited for large-scale cell disruption among all techniques investigated. 相似文献