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71.
践行绿色发展理念持续推进太湖水环境治理工程建设 总被引:2,自引:0,他引:2
总结分析了2007年太湖蓝藻爆发发生水危机后,实施调水引流、蓝藻打捞、湖泛监控、河湖清淤等水利项目所取得的明显成效和经验;针对目前太湖水环境治理中面临的新问题和贯彻新时期治水方针的要求,提出了用绿色发展理念引领新一轮治太水利工程建设,从加强河湖连通、河湖疏浚整治和城市"活水"工程建设的实践,阐述了这一方法论的科学性、有效性;系统思考了完善太湖流域水环境治理体系的建议。 相似文献
72.
Pollutant load reductions are often required to restore aquatic ecosystems experiencing eutrophication. Loads can be estimated using watershed models or data from monitoring stations, however data availability can limit the timeliness or comprehensiveness of the load estimates. We developed an approach to address this challenge that used watershed model results to estimate the proportion of annual nonpoint source nitrogen (N), phosphorus (P) and sediment (Sed) loads derived from unmonitored catchments. This proportion was multiplied by the nonpoint portion of United States Geological Survey (USGS) estimated annual river loads to account for annual variation in hydrologic conditions. Total loads were calculated as the sum of measured river loads, reported point sources from unmonitored areas and the estimated nonpoint source loads from unmonitored catchments. We applied this approach to the Chesapeake Bay because of its socio‐economic and ecological importance. Median watershed loads for N, P and Sed were 140, 6.4 and 3030 Mg year?1, respectively (1990–2004). Nonpoint source loads from the monitored areas constituted the greatest source of N, P and Sed (55, 47 and 74% respectively) to the Bay. The high N, P and Sed yield rates (7.3, 0.38 and 99 kg ha?1 year?1, respectively) from nonpoint loads originating from unmonitored areas near the Bay resulted in 25, 32 and 26% (N, P and Sed, respectively) of the Bay's total loads (excluding direct atmospheric deposition, shoreline erosion and oceanic inputs). Disproportionately high loads of P and Seds were associated with years that experienced elevated discharge whereas N loads were directly related to discharge. Error estimates indicated that our methods were most reliable for N (±6%) but reasonable for P (±22%) and provide an effective technique for the timely estimation of pollutant loads from watersheds with unmonitored catchments. Management strategies that decrease N deposition and reduce runoff to control P and Sed transport will effectively reduce pollutant loads. Published in 2010 by John Wiley & Sons, Ltd. 相似文献
73.
通过评价黄河流域河湖生态环境演变特征,探究其存在的问题,分析黄河流域河湖生态环境复苏目标与总体格局,探讨并提出黄河流域河湖生态环境复苏的实现路径.结果表明,黄河流域河湖生态环境系统正在由无序发展向有序发展转变.针对黄河流域河湖生态环境复苏面临的河湖生态环境脆弱、区域地下水超采、流域水土流失等主要问题,应从强化河湖监管、... 相似文献
74.
对花都湖工程的规划设计进行介绍,规划方案注重保护河道自然生境,充分利用历史和现状场地条件,突破了以往传统水利工程的生硬、单一和枯燥,将水安全、水生态、水文化、水景观融为一体,为河道整治、人工湖建设与现代城市水利建设理念相结合提供了一宗成功的案例。 相似文献
75.
针对河流微孔曝气系统复氧效率较低的问题,基于单因素试验和响应面优化试验,以氧体积传质系数为评价指标,研究了曝气系统氧传质过程中微孔曝气器孔径、曝气水深、盐度、BOD_(5)及表面活性剂十二烷基苯磺酸钠(SDBS)质量浓度对充氧性能的影响规律,并建立了多元二次回归模型,对曝气参数进行优化。结果表明:5种因素对氧体积传质系数均有影响,其影响的显著程度由大到小分别为曝气水深、SDBS质量浓度、盐度、微孔曝气器孔径、BOD_(5)质量浓度;微孔曝气器孔径和SDBS质量浓度、盐度和SDBS质量浓度之间存在显著的交互作用;模型预测值与试验值的相对误差在合理范围内,所建立的回归模型准确可靠。 相似文献
76.
Enrique Vsquez 《河流研究与利用》1989,3(1):381-392
The Orinoco River is one of the world's longest rivers (2060 km) and in terms of average water discharge (36000 m3 s?1) it ranks third. Seventy per cent of its basin (1.1 × 106km2) is found in Venezuela and the rest in Colombia. Due to the uneven distribution of the population toward the northern coastal areas (97 per cent of the population inhabits 55 per cent of the country with only 16 per cent of the surface waters) plans have been carried out to develop resources in the Orinoco Basin. So far these programs include mining (mainly iron and bauxite), oil exploration and extraction from the Orinoco Oil Belt, industry, river transport, and hydroelectric exploitation. Development of the latter has involved the construction of two dams on the Caroní River (the most important blackwater tributary of the Orinoco) and two more are planned on this same river. Hydroelectric projects are also being considered for the Orinoco River. Physicochemical and biological characterization has been regarded as of major importance to establish base-line information to detect and quantify possible alterations in this river which is considered to be in a pristine state. Systematic hydrobiological research has recently been carried out in the river, some of its major tributaries, and floodplain lakes, and a fair amount of knowledge has emerged mainly from its lower section. Phytoplankton studies have revealed the presence of over 400 species of algae. Zooplankton research has identified 116 taxa of rotifers and 58 taxa of cladocerans. In general plankton densities negatively correlate with water level. Diatoms were observed to predominate in the Orinoco River while Cyanophyta predominate in the studied floodplain lakes. Seventeen aquatic macrophyte species have been recorded in the lakes of the Orinoco with high densities of Eichhornia crassipes, Oxycarium cubense, and Paspalum repens. Rooted emergent and floating-plant cover tends to increase rapidly during high water. Some 318 species and subspecies of fish have been reported for the Orinoco Basin, even though this number is far from complete. Preliminary data have revealed different species associations among relatively close lakes with biomasses ranging between 30 to 900kg ha?1 displaying considerable variations in diversity and species richness. Fisheries along the Orinoco are mainly of a multispecific nature and their overall potential has been estimated as being in the order of 45 000t yr?1. In general, management plans have taken into consideration the multispecific potential of the Orinoco Basin but indicate a lack of sufficient knowledge of the physical, biological, and social aspects involved. Furthermore development plans tend to precede the generation of this basic knowledge, thereby increasing the risks of conflict among the various users of the resources involved. 相似文献
77.
Understanding the retention time of water in waterbodies during periods of no surface flow in dryland rivers provides an important context for evaluating the ecological importance of a waterhole to the river system. Time series of water level data were collected from 10 waterbodies spread across three river systems of the Lake Eyre Basin (LBE), Australia. Observed loss rates in the absence of surface flow were compared to modelled evaporation rates in order to determine whether open water evaporation was the main loss process from isolated waterholes and to what extent there is evidence of interaction between the surface water and any shallow groundwater aquifers. The modelled evaporation rates were determined using the Penman combination equation and meteorological data from the closest climate station in the region of the waterbodies. The modelled evaporation data were able to explain only some of the variability in the observed loss data but did highlight periods where other processes (including observation error) need to be invoked. These other possible processes, which include temporary groundwater connection and the effect of heat storage on the evaporation losses, probably contribute as much to the observed data variability as error introduced by the use of regional meteorological data. Assuming evaporation is the dominant process determining water loss in the absence of flow, the persistence of a waterhole is primarily dependent upon its depth when flow ceases. The annual loss shown by most waterbodies lies within the range of the modelled evaporation rate using the Penman combination equation and equates between 1.5 and 2.5 m per annum. The use of water level data in conjunction with the modelled evaporation rates was able to provide important insights into controls on waterbody loss rates and persistence. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
78.
本文表述既能抗御台风暴潮又能回卷波浪,集海塘、挡潮、交通、旅游多种功能于一体的两级台阶弧形组合防浪堤的设计基本点及其运用特性。 相似文献
79.
阐释"河流代言人"概念的法律内涵 总被引:2,自引:1,他引:1
从社会规范中的法律视角来看。“河流代言人”概念蕴含着的公共行政体制的法治理念、环境资源法学的基本理念。如何看待“河流代言人”理念中体现出来的人与自然的法律关系,以及如何对人与自然的关系进行法律定位,从制度、方法、理念上进行理性思考。 相似文献
80.
E. A. Olofin 《河流研究与利用》1988,2(2):167-174
In the main, the assessment of environmental impact of dams is not undertaken in feasibility surveys of dam-related projects in the Tropics, as it should. Consquently, post-implementation investigations (mostly by research students) continue to reveal undersirable effects. The lack of appropriate data on which to base predictions in proposed projects, or to assess environmental impacts in ongoing ones, is a major problem. It is argued that continuous monitoring of existing projects can help to fill this data gap. Such monitoring should cover the entire basin affected, taking into account environmental variables of the upstream, reservoir, and downstream systems. This paper considers the downstream system. Variables of importance include: soil erosion and sediment yield; channel morphometry; discharge and runoff pattern and volume; and changes in vegetation cover, water chemistry and water quality. Field measurements and observations, laboratory analyses, and statistical inferences are required to yield acceptable results. Such results are expected to enhance a better understanding (through impact assessment) and management of existing projects, on the one hand, and to aid wise predictions (at the feasibility stage) of environmental effects of new projects, on the other. 相似文献