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971.
The Economic Impact of Water Evaporation Losses from Water Reservoirs in the Segura Basin,SE Spain 总被引:1,自引:0,他引:1
David Martínez-Granados José Francisco Maestre-Valero Javier Calatrava Victoriano Martínez-Alvarez 《Water Resources Management》2011,25(13):3153-3175
In this paper we assess the economic impact of evaporation losses from great dams (GDs) and on-farm agricultural water reservoirs
(AWRs) in the semi-arid Segura River basin, SE Spain. Evaporation losses from water reservoirs reduce the high water use efficiency
reached in agriculture by means of other techniques such as well-built water pipes or drip irrigation and have a substantial
economic impact. Evaporation losses have been calculated using Class-A pan evaporation data and pan coefficients, whereas
their economic impact has been assessed using an economic mathematical programming model that simulates land and water allocation
in the different irrigated areas of the basin. Our results show that annual evaporation from GDs and AWRs represents 8.7%
of the water currently available for irrigation in the Segura basin. The economic impact of such losses has been estimated
in a reduction of 6.3% of the value of agricultural production and 5.4% of the farm net margin. As less water is effectively
available for farmers the basin’s irrigated area is reduced in a 7.5%. This impact is greater, in both absolute and relative
terms, in the areas accommodating the most intensive and profitable irrigated agriculture. The applied methodology and results
could be useful to regional water agencies and collective irrigation schemes for future planning and management, including
the assessment of alternatives for reducing evaporation from reservoirs. 相似文献
972.
The Shiyanghe river basin, an arid inland basin of northwest China, is taken as an example to analyze the risk for achieving the ecological planning objective in arid inland river basins under uncertainty conditions. Hydrology and management uncertainties that affect the accomplishment of ecological planning objective are analyzed quantitatively with the methods of Bayesian theory based Probabilistic model, scenario analysis and interval analysis. Bayesian probabilistic analysis method was used to analyze the hydrological uncertainties in the form of probability and interval distributions in planning period, while the scenario analysis method and interval method were used to analyze the managing uncertainties in the form of interval numbers. Instead of the ecological risk analysis, which for arid inland river basin, of studying the impact of environmental and human factor on ecological system, water resources and environment, we focused on analysing the possible impact of hydrological and management uncertainty factor on the ecological planning, and forecasting the degree of the completion under the uncertainty. Our study provided the probabilities of achieving ecological planning objective and the possible deviation of different scenarios. The more local water resources and higher level of local water resource utilization and management appeared to lead higher probability to achieve the ecological objective. This study can help environment and water resource managers and planner to formulate a rational planning for arid inland river basins under hydrological and management uncertainty. 相似文献
973.
Luis Garrote Francisco Martin-Carrasco Francisco Flores-Montoya Ana Iglesias 《Water Resources Management》2007,21(5):873-882
One crucial aspect of drought management plans is to establish a link between basin drought state and management actions.
Basin state is described by a drought indicator system that includes variables like precipitation, streamflow, reservoir inflow,
reservoir storage and groundwater piezometric levels. Basin policy consists on a catalogue of management actions, ranging
from enforcing demand reduction strategies to establishing priority of users to allocate scarce water or approving emergency
works. In this paper, the methodology applied in the Tagus Basin Drought Management Plan to link operational drought indicators
to policy actions in regulated water supply systems is presented. The methodology is based on the evaluation of the probability
of not being able to satisfy system demands for a given time horizon. A simplified model of every water resources system in
the basin was built to evaluate the threshold of reservoir volume that is required to overcome the drought situation without
deficit. For each reservoir level, a set of policy actions is proposed with the goal of guaranteeing essential demands during
drought conditions. The methodology was validated with a simulation of system behavior for 60 years of historic streamflow
series, finding acceptable results in most systems. 相似文献
974.
Reservoir operation rules are intended to help an operator so that water releases and storage capacities are in the best interests
of the system objectives. In multi-reservoir systems, a large number of feasible operation policies may exist. System engineering
and optimization techniques can assist in identifying the most desirable of those feasible operation policies. This paper
presents and tests a set of operation rules for a multi-reservoir system, employing a multi-swarm version of particle swarm
optimization (MSPSO) in connection with the well-known HEC-ResPRM simulation model in a parameterization–simulation–optimization
(parameterization SO) approach. To improve the performance of the standard particle swarm optimization algorithm, this paper
incorporates a new strategic mechanism called multi-swarm into the algorithm. Parameters of the rule are estimated by employing a parameterization–simulation–optimization approach,
in which a full-scale simulation model evaluates the objective function value for each trial set of parameter values proposed
with an efficient version of the particle swarm optimization algorithm. The usefulness of the MSPSO in developing reservoir
operation policies is examined by using the existing three-reservoir system of Mica, Libby, and Grand Coulee as part of the
Columbia River Basin development. Results of the rule-based reservoir operation are compared with those of HEC-ResPRM. It
is shown that the real-time operation of the three reservoir system with the proposed approach may significantly outperform
the common implicit stochastic optimization approach. 相似文献
975.
In recent years, droughts with increasing severity and frequency have been experienced around the world due to climate change
effects. Water planning and management during droughts needs to deal with water demand variability, uncertainties in streamflow
prediction, conflicts over water resources allocation, and the absence of necessary emergency schemes in drought situations.
Reservoirs could play an important role in drought mitigation; therefore, development of an algorithm for operation of reservoirs
in drought periods could help to mitigate the drought impacts by reducing the expected water shortages. For this purpose,
the probable drought’s characteristics and their variations in response to factors such as climate change should be incorporated.
This study aims at developing a contingency planning scheme for operation of reservoirs in drought periods using hedging rules
with the objective of decreasing the maximum water deficit. The case study for evaluation of the performance of the proposed
algorithm is the Sattarkhan reservoir in the Aharchay watershed, located in the northwestern part of Iran. The trend evaluations
of the hydro-climatic variables show that the climate change has already affected streamflow in the region and has increased
water scarcity and drought severity. To incorporate the climate change study in reservoir planning; streamflow should be simulated
under climate change impacts. For this purpose, the climatic variables including temperature and precipitation in the future
under climate change impacts are simulated using downscaled GCM (General Circulation Model) outputs to derive scenarios for
possible future drought events. Then a hydrological model is developed to simulate the river streamflow, based on the downscaled
data. The results show that the proposed methodology leads to less water deficit and decreases the drought damages in the
study area. 相似文献
976.
977.
978.
979.
Jan Bonenkamp 《De Economist》2009,157(1):49-77
Summary This paper assesses how the Dutch system of occupational pensions redistributes between and within generations. The approach
in this paper deviates from the usual approach by incorporating the full life cycle in the measurements, rather than only
the annual effects. In order to quantify redistribution, we use the level of educational attainment, gender and age to classify
the pension fund population. For all groups distinguished, we measure in present value terms the average net benefit from
participating in occupational pensions. The results indicate a sizable redistribution from males to females and from low educated
to higher educated workers. On a lifetime basis, the impact of intergenerational transfers is modest.
I am grateful to the two anonymous referees, Ed Westerhout, Casper van Ewijk, Lex Meijdam, Yvonne Adema and Peter Kooiman
for their helpful comments on earlier drafts of this paper, and to Andre Nibbelink for his valuable computational assistance. 相似文献
980.
Financial globalisation has been associated with divergent current account patterns in emerging markets. In this paper we
test for the relevance of financial market characteristics in explaining different current account patterns in emerging Europe
and emerging Asia. We find that better developed and more integrated financial markets increase emerging markets’ ability
to borrow abroad. The degree of financial integration within the convergence clubs as well as the extent of reserve accumulation
are found to be the most significant factors to explain divergent current account patterns in emerging Europe and emerging
Asia. 相似文献