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61.
中国北方多属半干旱、半湿润地区,其降雨径流的形成过程较为复杂,既有蓄满产流,又有超渗产流,针对这种产流现象,分析其物理机制,在前人研究的基础上,探讨了适用于超渗产生地表径流、超持产生壤中流的"双超"产流模型和汇流模型,并将其应用于文峪河流域,进行了洪水模拟应用,研究结果表明,洪水过程的模拟预测结果与实测结果基本吻合;对于不同年份降雨的洪水模拟,除少数敏感的模型参数外,其它模型参数几乎不变,说明该模型弹性较好,因此该模型在这类地区具有较强的适用性和实用性。 相似文献
62.
为评价降雨输入对青龙河流域BASINs/HSPF模型模拟结果的影响,改善HSPF模型模拟精度,应用趋势成分建模、周期成分建模、相依随机建模和独立随机建模(白噪声)等随机建模程序和蒙特卡洛计算机模拟方法,获得200组降雨随机模拟序列,分别作为青龙河流域BASINs/HSPF模型的输入,以Nash-Sutcliffe效率系数(ENS)作为模型模拟效果的评价标准,获得如下结论:采用趋势成分、周期成分与ARMA建模以及正态随机模拟获得降雨随机模拟序列是量化降雨输入随机性的可行方法;在模型参数优化的条件下,降雨随机模拟序列HSPF模拟ENS值的变化区间为[71.09%,74.96%],波动幅度达3.87%,表明降雨输入随机性对于HSPF模拟结果具有显著影响;当考虑每年的日降雨量极大值时,ENS值变化区间为[75.35%,78.81%],波动幅度达3.46%,且结果均优于没有考虑降雨极大值点的降雨随机模拟序列,表明降雨时间序列的极大值点对于HSPF模拟效果具有显著影响;随着降雨时间序列中所考虑极大值点数量的逐渐增多,HSPF模拟效果出现下降趋势,表明HSPF模拟应特别关注若干最大极值点的影响;降雨输入的不确定性是HSPF模型模拟结果不确定性的重要来源,改善HSPF模拟效果需要考虑降雨时间序列随机性和极值点因素的影响.本研究可为量化降雨输入对HSPF模型模拟的影响以及HSPF模拟的降雨情景优选提供借鉴. 相似文献
63.
雨雪天气下特高压交流单回试验线段电晕损失实测分析 总被引:1,自引:1,他引:1
为了研究特高压交流输电线路在雨天、雪天气象条件下的电晕损失特性,基于我国特高压交流试验基地单回试验线段展开实测研究,采用研制的光电数字化输电线路电晕损失监测系统,实现了试验线段电晕损失全天候条件下实时在线测量,根据监测结果分析不同降雨率及大雪气象条件下电晕损失。研究结果表明,正常运行电压下,特高压交流单回试验线段雨天单相单位长度电晕损失约为20~60 W/m,在大雪气象条件下,根据监测结果,特高压交流单回试验线段单位长度电晕损失最大值为:边相达到53.54 W/m,中相达到62.95 W/m,与等值降雨率推算结果较为符合。电晕损失随降雨率增大呈非线性增长,在大雨条件下逐渐趋于饱和,并初步获得8×LGJ-500/35分裂导线降雨率与电晕损失拟合模型。该试验获得的特高压交流单回试验线段电晕损失实测结果,为特高压交流输电线路导线选型设计及运行经济性衡量提供了参考。 相似文献
64.
将降雨数值预报产品运用到水文预报中已经逐渐成为提高洪水作业预报的预见期的重要手段。为充分了解ECMWF(European Centre for Medium Range Weather Forecasts)和WRF(Weather Research and Forecasting model)2种数值天气预报产品对嘉陵江研究区面雨量预报的预报精度和误差分布,且为增强洪水预报精度的稳健性提供科学支持,采用TS评分、空报率、漏报率、正确率等指标,对嘉陵江地区7个气象分区内的2016年汛期面雨量预报结果进行了检验,分析了不同分区内各检验指标与预报时效的关系。结果表明:ECMWF数值预报产品和WRF数值预报产品均可用于该地区晴雨预报,且2种产品的预报精度随降水等级的增大呈增大趋势,随预报时效的增加呈减小趋势。综合而言,ECMWF数值预报产品对嘉陵江研究区的预报效果更好。 相似文献
65.
Nadhir Al-Ansari ;Mawada Abdellati ;Mohammad Ezeelden ;Salahalddin S. Ali ;Sven Knutsson 《土木工程与建筑:英文版》2014,(6):790-805
Iraq is facing water shortage problem despite the presence of the Tigris and Euphrates Rivers. In this research, long rainfall trends up to the year 2099 were studied in Sulaimani city northeast Iraq to give an idea about future prospects. The medium high (A2) and medium low B2 scenarios have been used for purpose of this study as they are more likely than others scenarios, that beside the fact that no climate modeling canter has performed GCM (global climate model) simulations for more than a few emissions scenarios (HadCM3 has only these two scenarios) otherwise pattern scaling can be used for generating different scenarios which entail a huge uncertainty. The results indicate that the average annual rainfall shows a significant downward trend for both A2 and B2 scenarios. In addition, winter projects increase/decrease in the daily rainfall statistics of wet days, the spring season show very slight drop and no change for both scenarios. However, both summer and autumn shows a significant reduction in maximum rainfall value especially in 2080s while the other statistics remain nearly the same. The extremes events are to decrease slightly in 2080s with highest decrease associated with A2 scenario. This is due to the fact that rainfall under scenario A2 is more significant than under scenario B2. The return period of a certain rainfall will increase in the future when a present storm of 20 year could occur once every 43 year in the 2080s. An increase in the frequency of extreme rainfall depends on several factors such as the return period, season of the year, the period considered as well as the emission scenario used. 相似文献
66.
《Urban Water Journal》2013,10(3):195-208
Storage facilities are key devices in mitigating the urban drainage impact on receiving water bodies, but their design is still affected by high uncertainty. The analytical-probabilistic approach has recently raised interest, because the facility performances are directly related to probability. Starting from statistically independent storm events, distributions of the meteorological variables must be fitted. Rainfall series, recorded in three Italian raingauges, were examined for appraising two main concerns: the choice of proper probability distributions for rainfall volume and the sample sensitivity with respect to the analysis criterion. The analytical derivation of the model is then finally discussed. 相似文献
67.
《Urban Water Journal》2013,10(5):370-378
This study conducted statistical analysis under both stationary and non-stationary climate using rainfall data measured in Seoul, South Korea. The 50 year annual maximum rainfall data were analysed with generalised extreme value distribution and Gumbel distribution. Possible rainfall changes were predicted with nonstationary forms of the two distributions, considering time variable location parameters. The current storm sewer design criteria were assessed by reflecting climate change implications and expected lifetime performance. Expected return periods were reduced to 4.67, 8.66, 19.16 and 23.53 years for the current 10 min - 5, 10, 30 and 50 years. The newly suggested design criteria of 5, 10, 30 and 50 yr return period storm events were 5.3, 12, 48 and 107 years for the 10 min duration for a 50 year lifetime expectancy. 相似文献
68.
《Urban Water Journal》2013,10(6):411-421
The distribution of bacterial contaminants (Escherichia coli and total coliforms) and nutrients (nitrogen and phosphorus) in a rapidly growing metropolitan area, the Las Vegas Valley, were studied to assess the contributions of point and nonpoint pollution sources under dry weather flow (pre rainfall) and wet weather flow (post rainfall) events. Nonpoint sources emanating from urban centers and septic seepage were found to be a primary source of bacterial contamination in the Las Vegas Wash, a mainstream wash channel where the Las Vegas Valley watershed drains. Contribution of point sources (wastewater treatment plants) to E. coli and total coliforms were found to be negligible. However, data in the Tropicana/Flamingo Wash, a tributary of the Las Vegas Wash, showed high bacterial activities in the wet antecedent rainfall condition as compared to the pre-rain dry antecedent condition suggesting that the rainfall increased bacterial activities. 相似文献
69.
洪水峪泥石流、沟内崩塌、不稳定斜坡等不良地质现象发育。该沟内煤矸石、沟道物源丰富,上游汇水面积大,沟道纵坡降较大,在强降雨沟道径流冲刷作用下,极易发生揭底起动而形成泥石流灾害。在雨季,支沟常有少量泥沙、块石冲出,阻塞进山道路,淤塞河道,引起原有坝体损毁,威胁居民生命财产安全。通过对以往资料的综合整理,结合现场调查,对洪水峪泥石流形成的诸多条件进行了分析,以期对该区泥石流的防治与预测起到参考作用。 相似文献
70.