全文获取类型
收费全文 | 151534篇 |
免费 | 4352篇 |
国内免费 | 27篇 |
专业分类
财政金融 | 25736篇 |
工业经济 | 11569篇 |
计划管理 | 21671篇 |
经济学 | 29219篇 |
综合类 | 1465篇 |
运输经济 | 955篇 |
旅游经济 | 2482篇 |
贸易经济 | 23501篇 |
农业经济 | 6134篇 |
经济概况 | 17101篇 |
水利工程 | 15832篇 |
信息产业经济 | 8篇 |
邮电经济 | 240篇 |
出版年
2021年 | 1068篇 |
2020年 | 1791篇 |
2019年 | 2623篇 |
2018年 | 2798篇 |
2017年 | 2840篇 |
2016年 | 3125篇 |
2015年 | 2358篇 |
2014年 | 3774篇 |
2013年 | 16259篇 |
2012年 | 4806篇 |
2011年 | 4686篇 |
2010年 | 4070篇 |
2009年 | 4696篇 |
2008年 | 4297篇 |
2007年 | 3772篇 |
2006年 | 4018篇 |
2005年 | 4001篇 |
2004年 | 3555篇 |
2003年 | 3111篇 |
2002年 | 3122篇 |
2001年 | 2937篇 |
2000年 | 2773篇 |
1999年 | 2694篇 |
1998年 | 2514篇 |
1997年 | 2620篇 |
1996年 | 2472篇 |
1995年 | 2252篇 |
1994年 | 2262篇 |
1993年 | 2267篇 |
1992年 | 2343篇 |
1991年 | 2177篇 |
1990年 | 2031篇 |
1989年 | 1908篇 |
1988年 | 1819篇 |
1987年 | 1825篇 |
1986年 | 1849篇 |
1985年 | 2643篇 |
1984年 | 2519篇 |
1983年 | 2325篇 |
1982年 | 2193篇 |
1981年 | 2131篇 |
1980年 | 2164篇 |
1979年 | 2061篇 |
1978年 | 1893篇 |
1977年 | 1833篇 |
1976年 | 1642篇 |
1975年 | 1488篇 |
1974年 | 1401篇 |
1973年 | 1402篇 |
1972年 | 1101篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
191.
192.
In this paper we will analyze the relationship between the value and duration moments of a cash flow and movements in the yield curve. We will show that for changes in the yield curve which can be related to tn , the 1st order changes in the net present value of a cash flow are linearly dependent on the n + lth duration moments, and that the 2nd order changes are dependent on the sum of duration moments of order 2 n + 1 and 2 n + 2. We will use this relationship to tilt tracking portfolios so as to protect them against specific changes in the yield curve. 相似文献
193.
Objections to the teaching of business ethics 总被引:1,自引:0,他引:1
194.
In this paper, we examine the warrant price and stock price reactions to the announcement of warrant life extensions by REITs. As predicted by option pricing theory, warrant prices increase in response to these extensions. The stocks of REITs making the extension announcements experience average abnormal returns that are not significantly different from zero. Thus, total firm value appears to increase, with the gains accruing primarily to the warrantholders. 相似文献
195.
Li Yu-cheng He Ming Dept.of Civil Engineering Dalian Univ.of Technology Dalian P.R.China 《水动力学研究与进展(B辑)》1993,(4)
Based on model test,the statistical distribution of extreme values of wave-current in-line forces acting on vertical circular cylinder is analyzed in this paper.It is shownthat the results calculated by the simplified method,proposed by authors,agree well with the testdata;Weibull distribution is also adoptable in the region of high KC number, and the shapeparameter a and scale parameter β are related well with KC number respectively. 相似文献
196.
197.
R.Q. Doeswijk 《De Economist》1997,145(4):573-598
The efficient markets hypothesis states that at any times security prices fully reflect all available information. Contrarian investment strategies do not recognize the efficiency of capital markets. They call for buying undervalued stocks, i.e. stocks with a low price relative to their fundamentals. The idea behind such a strategy is to take advantage of the extrapolation behaviour of naive investors. Using a fresh and extensive data set from the Dutch stock market, we found that these strategies yield an outperformance without a higher risk. Our results make it hard to maintain the efficient market hypothesis. 相似文献
198.
199.
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
200.
Li Wang ping Mechanics Department Huazhong University of Science Technology Wuhan P.R.China Yeo K.S. Khoo B.C. Mechanical Production Engineering Department National University of Singapore 《水动力学研究与进展(B辑)》1999,(3)
1. INTRODUCTIONThemaingoalofthispaperistoexplorethepossibilitytolearnmoreaboutthemechanismofturbulentboundarylayerflowinteractionsanditseffectsoncompliantwallperformance.Therearecertainprerequisiteconditionstofurtherthestudyonthemechanism,i.e.theco… 相似文献