全文获取类型
收费全文 | 154024篇 |
免费 | 3749篇 |
国内免费 | 26篇 |
专业分类
财政金融 | 26067篇 |
工业经济 | 11634篇 |
计划管理 | 22240篇 |
经济学 | 30038篇 |
综合类 | 1490篇 |
运输经济 | 963篇 |
旅游经济 | 2498篇 |
贸易经济 | 23804篇 |
农业经济 | 6166篇 |
经济概况 | 17109篇 |
水利工程 | 15495篇 |
信息产业经济 | 7篇 |
邮电经济 | 288篇 |
出版年
2021年 | 1079篇 |
2020年 | 1811篇 |
2019年 | 2625篇 |
2018年 | 2739篇 |
2017年 | 2764篇 |
2016年 | 3112篇 |
2015年 | 2381篇 |
2014年 | 3807篇 |
2013年 | 16389篇 |
2012年 | 4808篇 |
2011年 | 4645篇 |
2010年 | 4054篇 |
2009年 | 4708篇 |
2008年 | 4332篇 |
2007年 | 3812篇 |
2006年 | 4144篇 |
2005年 | 4060篇 |
2004年 | 3708篇 |
2003年 | 3195篇 |
2002年 | 3182篇 |
2001年 | 3026篇 |
2000年 | 2845篇 |
1999年 | 2730篇 |
1998年 | 2605篇 |
1997年 | 2654篇 |
1996年 | 2519篇 |
1995年 | 2308篇 |
1994年 | 2332篇 |
1993年 | 2315篇 |
1992年 | 2381篇 |
1991年 | 2243篇 |
1990年 | 2089篇 |
1989年 | 1945篇 |
1988年 | 1848篇 |
1987年 | 1860篇 |
1986年 | 1876篇 |
1985年 | 2679篇 |
1984年 | 2588篇 |
1983年 | 2392篇 |
1982年 | 2262篇 |
1981年 | 2180篇 |
1980年 | 2198篇 |
1979年 | 2110篇 |
1978年 | 1920篇 |
1977年 | 1838篇 |
1976年 | 1650篇 |
1975年 | 1502篇 |
1974年 | 1405篇 |
1973年 | 1409篇 |
1972年 | 1108篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
V. I. Shtykov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1998,32(8):459-462
Conclusions 1. Use of dewatering systems based on voidless drainage is most effective when dewatering slightly permeable soils in regions
with a deep seasonal frost.
2. Two-story drainage with the upper and lower stories spaced 30 m apart accelerates the discharge of gravitational water
from the arable layer. Results of observations on two-story drainage in experimental-production sections indicated that it
discharges 2 – 3.8 times more water than systematic tubular drainage with an interdrain spacing of 10 m and a 0.2-m thick
three-dimensional filter of a sandy-gravelly mixture.
3. It is recommended to use crushed stone and porous-clay gravel with a fineness of 10 – 20 mm as a filler. In that case,
protection of the drain filler is, as a rule, required only from the intrusion of soil from above during construction in cohesive
soils with a plasticity indexW
p≥7.
4. seepage rate in a voidless drain should be lower than the scouring velocity for the soil in which the voidless drainage
is placed. In the opposite case, it is necessary to lower the grade of the drains or select a filler gradation such that the
seepage rate in the drain be lower than the scouring velocity.
Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 8, pp. 41–43, August, 1998. 相似文献
92.
Rudy K. Moenaert Dirk Deschoolmeester Arnoud De Meyer William E. Souder 《R&D Management》1992,22(1):021-040
Abstract The research question in the present article can be phrased in the following way: what are the elements which influence the perception of the utility of information received from another function? A field study research has been conducted in 40 Belgian companies. In each company, we have studied two on-going innovation projects (one planning project, one development project). Crossfunctional communication behaviours at the R&D/marketing interface have been measured by means of mailed structured questionnaires. Three-hundred and eighty-six questionnaires have been returned. The data analyses show that there are four underlying information dimensions, i.e. the perceived relevance, the perceived comprehensibility, the perceived novelty and the perceived credibility of information. We also discuss some contingency variables (function of the message receiver, stage in the innovation process) that might moderate the impact of these dimensions. It will be shown that the interaction between source and receiver has a significant impact on the perceived credibility, the perceived comprehensibility and the perceived novelty of the received information. 相似文献
93.
The Graph Model for Conflict Resolution is a flexible methodology for systematically studying strategic conflicts in the real world, and is therefore a natural tool for negotiation support. The basic definitions underlying the graph model are reviewed, and the techniques for analysis and interpretation are discussed. The modeling and analysis of a case study, an international trade negotiation concerning the export of Canadian softwood lumber to the United States, are used to demonstrate the practical application of the Graph Model for Conflict Resolution as a negotiation support tool. The modeling and analysis is carried out using the GMCR software system. The ability of the Graph Model for Conflict Resolution to provide insights and advice to negotiators is emphasized. 相似文献
94.
95.
Consumers act out roles throughout their lives. Marketers assist in this role playing by providing the wardrobes, props, and sets in the form of products and services. They also help people understand acceptable role behavior by portraying roles in their communication programs. Consumers assume new roles as they age. This article is designed to enhance understanding of the often-ignored roles that accompany aging and provides examples of and suggestions for effective marketing for these role transitions. 相似文献
96.
The paper extends Manning's model on education and balanced growth to include labour immigration. Each immigration unit is assumed to consist of one skilled worker and some unskilled members. The optimal immigration policy which maximizes the per capita steady-state consumption of the host country is derived. We show that optimal immigration policy can reduce the steady-state skilled labour ratio. More interesting still, contrary to the widespread belief that immigration of skilled workers hurts local skilled workers, it is the unskilled local workers whose interests are threatened by optimal immigration policy. 相似文献
97.
The introduction of traffic management schemes has been one response of the National Parks to the problem of ever-increasing car-borne visitors and the consequent damage caused to the rural environment. By reviewing these schemes and by determining and explaining attitudes towards one particular traffic management experiment, the paper aims to deduce lessons for future policy. The analysis, based on two visitor surveys, suggests that the likelihood of success is improved when schemes are integrated, containing both ‘carrot’ and ‘stick’ elements. Since public perceptions are also found to be pivotal to its success, appropriate marketing of a scheme is vital. The paper concludes, however, that to achieve the fundamental objective of greater accessibility with less mobility, a more wide-ranging marketing effort is required intended to engender a sea change in attitude towards both the car and public transport. 相似文献
98.
99.
Linear and nonlinear Granger causality tests are used to examine the dynamic relation between daily Dow Jones stock returns and percentage changes in New York Stock Exchange trading volume. We find evidence of significant bidirectional nonlinear causality between returns and volume. We also examine whether the nonlinear causality from volume to returns can be explained by volume serving as a proxy for information flow in the stochastic process generating stock return variance as suggested by Clark's (1973) latent common-factor model. After controlling for volatility persistence in returns, we continue to find evidence of nonlinear causality from volume to returns. 相似文献
100.
This article investigates the change in operating performance of firms as they make the transition from private to public ownership. A significant decline in operating performance subsequent to the initial public offering (IPO) is found. Additionally, there is a significant positive relation between post-IPO operating performance and equity retention by the original entrepreneurs, but no relation between post-IPO operating performance and the level of initial underpricing. Post-issue declines in the market-to-book ratio, price/earnings ratio, and earnings per share are also documented. 相似文献