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91.
杨立法 《昆明理工大学学报(自然科学版)》2013,(5):22-27
给出KML空间数据查询的解决方案,并在基于Google地图建立的Web地理信息系统中予以实现.该方案采用Linq to XML方法实现KML属性查询,采用Net Topology Suite计算空间对象之间的拓扑关系,综合应用此两种技术解决KML空间查询.基于此方案,在VS2010中开发出一套交互式KML空间查询工具,包括点选、连选、区域选择、依属性选择、去选等. 相似文献
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《Measurement》2016
Compressive strength and direct shear testing parameters on unsaturated soil are often used in analysis and design of several geotechnical infrastructures. Rarely, any attempt has been made to quantify shear strength of unsaturated soil under different net normal stress conditions. The objectives of this study are to quantify shear strength parameters of unsaturated silty sand and to establish a simple correlation of it with unconfined compressive strength. Consolidated drained direct shear tests and unconfined compressive strength tests were performed to determine shear strength of unsaturated completely decomposed granite (CDG) soil. To interpret this, a series of typical soil water characteristic curves (SWCC) of CDG soil under different net normal stresses were also measured. Experimental results show that the unsaturated shear strength significantly increases with increase in net normal stress and matric suction. A new model for prediction of unconfined compression strength of unsaturated soil from shear strength and initial suction was proposed. The predictions from newly proposed model were found to be consistent with the measured unconfined compressive strength. This correlation can be useful in economical and rapid design/analysis of geotechnical infrastructure. 相似文献
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介绍了抚顺石化MES生产统计报表设计与开发的方法,在物料移动及物料平衡系统的系统设计实施基础上,对生产运行管理部门和生产操作层用户的业务进行了充分分析,通过在B/S模式下,利用VBA技术实现ORACLE数据库与Excel报表的交互,根据抚顺石化公司的业务状况,设计开发出了报表系统,统一了公司各直属单位的企业生产统计报表格式,提高了管理水平。 相似文献
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Detection and mapping of long-term land degradation using local net production scaling: Application to Zimbabwe 总被引:3,自引:0,他引:3
Degradation of vegetation and soils in drylands, sometimes called desertification, is thought to be a serious threat to the sustainability of human habitation, but maps of the extent and severity of degradation at country and global scales do not exist. Degraded land, by definition, has suffered a change relative to its previous condition set by its climate, soil properties, topography and expectations of land managers. The local net production scaling (LNS) method, tested here in Zimbabwe, estimates potential production in homogeneous land capability classes and models the actual productivity using remotely-sensed observations. The difference between the potential and actual productivities provides a map of the location and severity of degradation. Six years of 250 m resolution MODIS data were used to estimate actual net production in Zimbabwe and calculate the LNS using three land capability classifications. The LNS maps agreed with known areas of degradation and with an independent degradation map. The principal source of error arose because of inhomogeneity of some land capability classes caused by, for example, the inclusion of local hot-spots of high production and differences in precipitation caused by local topography. Agriculture and other management can affect the degradation estimates and careful inspection of the LNS maps is essential to verify and identify the local causes of degradation. The Zimbabwe study found that approximately 16% of the country was at its potential production and the total loss in productivity due to degradation was estimated to be 17.6 Tg Cyr− 1, that is 13% of the entire national potential. Since the locations of degraded land were unrelated to natural environmental factors such as rainfall and soils, it is clear that the degradation has been caused by human land use, concentrated in the heavily-utilized, communal areas. 相似文献
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Simulation-based life cycle assessment of energy efficiency of biomass-based ethanol fuel from different feedstocks in China 总被引:2,自引:0,他引:2
Interests in biomass-based fuel ethanol (BFE) have been re-boosted due to oil shortage and environmental deterioration. Biomass-based fuel ethanol is renewable and, apparently, environmentally friendly. Biomass-based E10 (a blend of 10% ethanol and 90% gasoline by volume) is a promising conventional gasoline substitute, because vehicle engines require no modifications to run on E10 and vehicle warranties are unaffected. This paper presented life cycle assessments (LCAs) of energy efficiency of wheat-based E10 from central China, corn-based E10 from northeast China, and cassava-based E10 from southwest China. The respective energy flow-based evaluation model of wheat-, corn-, and cassava-based E10 was built based on data from pilot BFE plants. Monte Carlo method is applied to deal with the uncertain parameters and input and output variables of the evaluation model because of its wide application and easy development of statistical dispersion of calculated quantities. According to the assessment results, the average energy input/output ratio of wheat-based fuel ethanol (WFE), corn-based fuel ethanol (CFE), and cassava-based fuel ethanol (KFE) is 0.70, 0.75, and 0.54, respectively, and biomass-based E10 vehicle can have less fossil energy demand than gasoline-fueled ones. 相似文献