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11.
乐滩水库引水灌区一期工程隧洞12座,总长为48.77 km,均为无压隧洞,针对隧洞从村屯附近穿越、长距离、低水头、大流量的特点,设计有针对性地提出了一些新观点。结合工程实际,从洞线选择、进出口布置、合理加大隧洞水深、减糙衬砌混凝土使用、TBM法施工应用等简述其设计要点。 相似文献
12.
灌区量水是灌区实现"总量控制"和"定额管理"的基础性工作.通过圆弧直墙平底量水槽试验研究和示范推广,为我省灌区防洪度汛、抗旱、供水调度、计量收费提供科学依据,改善管理人员测流工作环境,减轻工作人员劳动强度,提高测流精度和测流工作效率,节约管理费用开支,提高灌区的现代化管理水平. 相似文献
13.
Miscanthus biomass yield can be limited by poor rhizome establishment and this is linked to rhizome age and storage conditions prior to planting. To avoid poor establishment, best practice recommends field planting directly after rhizome division. Operations avoiding rhizome storage, and utilising favourable climatic conditions at planting, may be climatologically and logistically challenging when large areas are planted at high rhizome densities. Our aim is to evaluate storage regimes to maintain rhizome viability and maximise establishment when planted under optimal conditions. To achieve this we have compared differences in site pre-planting management (level of soil cultivation) strategies, along with post-planting treatments (irrigation and soil mulching with compost), against differences in storage regime (temperature) and duration. The results from a rhizome establishment bioassay showed viability at lifting in early March was high, while cold storage of rhizomes had no negative influence on viability and growth. There were no negative impacts of storage temperature on rhizome mineral or carbohydrate concentrations. Increases in air temperature enhanced rhizome and culm final biomass and rate of establishment. Application of irrigation, or compost mulch, to field rhizome plantings improved establishment increasing soil moisture levels in early May through August. In conclusion, cold storage of rhizomes is achievable and effective in maintaining rhizome viability and can be used to extend the planting time. Soil moisture and application of supplementary irrigation was important during establishment. Also important was the avoidance of weed competition. Achieving the most appropriate conditions for optimal establishment will be critical in regions where spring/summer rainfall is restrictive. 相似文献
14.
我省节水农业的技术体系与发展思路 总被引:4,自引:0,他引:4
本文论述了我省节水农业的重大战略意义,并提出出了节水灌溉技术体系和发展思路。 相似文献
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以GIS技术支持下的江西省农田节水灌溉系统为研究对象,阐述了系统研究的主要内容、方法和技术框架,并对GIS技术在节水灌溉中应用的特点及优势进行了分析。 相似文献
17.
舍埠排灌站基础在施工过程中遇到了流沙,出现了管涌现象,边坡塌方严重,基础受到破坏.必须采取相应的措施,进行加固处理,保证地基的稳定.本文结合实践和经验,介绍以松木桩加块石挤淤的方法来处理基础. 相似文献
18.
Water use patterns are not distributed evenly over space and time. Determining the amount of water used within a region, as
well as the various ways in which water is used is important for making adequate and sustainable water management policies
and determining future water availability. We examined differences in spatial trends in Oregon freshwater use (total, municipal,
and agricultural water withdrawals), by county, between the years 1985 and 2005. We also explored biophysical and socioeconomic
factors that explain spatial patterns using Moran’s I, local index of spatial autocorrelation (LISA), and spatial regression
models. There was a moderate positive spatial autocorrelation among counties that had similar total and irrigation withdrawals.
LISA analysis identified hot spots between certain arid agricultural counties in the southeastern Oregon and cold spots between
certain humid northwestern counties, including within the Portland metro area. Annual precipitation and income are negatively
associated with total water withdrawals. Summer temperature and farm size is positively associated with irrigation water withdrawals,
while net cash return and income are negatively associated with irrigation water withdrawals. When compared to ordinary least
square regression models, spatial error models that take into account spatial dependence provide a more comprehensive explanation
of the variations of water use, suggesting that water resource planning and management should incorporate spatial and neighborhood
effects to effective manage limited natural resources. 相似文献
19.
20.
Abdrabbo A. Abou Kheira 《Water Resources Management》2009,23(11):2317-2342
The Egyptian Ministry of Water Resources and Irrigation (MWRI) has expressed concern about the current high cost of the Irrigation Improvement Project (IIP) implemented in the “old lands” of the lower reaches of the Nile River. Because the IIP is financed through fees paid by the direct beneficiaries of the project, i.e., irrigation water users, these same Egyptian agricultural producers are especially sensitive to the higher than expected costs that the project has incurred to date. The objective of the current study is to evaluate whether this cost reduction is associated with any deficiency in irrigation performance. This Monitoring and Evaluation (M&;E) study aims to answer questions such as: Does reducing pump capacity and increased pump operation affect the farmers negatively? And, does the use of electricity instead of diesel fuel affect the farmers positively? Six indicators were used to compare new design criteria in the W10 and the IIP1 irrigation system designs, water savings, irrigation cost, irrigation time, night irrigation, and land savings. The W10 project design achieved the minimum actual operating cost per unit of area and per unit of water compared to the IIP1 project design on both Meet Yazied and El-Mesk Canals. The total cost per unit of area in the W10 project design is lower than IIP1 by 19.33% and 24.92% on the Meet Yazied and El-Mesk Canals, respectively. The total cost per unit of water in the W10 design is also lower than IIP1 on the Meet Yazied and El-Mesk Canals. Average irrigation time for rice and cotton crops cultivated in the W10 area are higher than average irrigation time for these crops cultivated in the IIP1 area for all locations on the Mesqa (head, middle and tail), because of increased pump operation in the W10 area (16 to 20 h d???1). The number of irrigation events at the head of the Sefsafa Canal in the W10 area is higher than on the Meet Yazied and El-Mesk Canals in the IIP1 areas because of the increased pump operation in the W10 area. 相似文献