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51.
United States Geological Survey streamflow data are commonly used for hydraulic model calibration and boundary conditions. The transitory nature of sand-bed rivers’ bathymetry is problematic for the traditional automated stream gauging methods used by the USGS. This note seeks to assess the limitations of streamflow measurements for use in hydraulic models. An overview of USGS rating-curve development and use is presented with a focus on the specific challenges of sand-bed rivers. Measurements from three consecutive USGS gauges for a storm event on the Rio Grande in Albuquerque, New Mexico, illustrate the outlined problems with rating curves. These gauges are utilized to study the impact of uncertainty in rating-curve discharges on hydraulic model results. A one dimensional hydraulic model of the study reach indicates up to 25% reduction in the calculated flow depth if questionable rating-curve discharges are used as model input. Recommendations for using USGS streamflow data in hydraulic models are outlined. 相似文献
52.
53.
该文从空间入手,以杭州城西水街为例,研究了水与城市有机结合的方法和必要性,阐明其中所蕴含的文化沉积和历史底蕴是值得我们去感悟的。 相似文献
54.
Der-Fong Juang Chao-Hsien Lee Chung-Shin Yuan 《The Science of the total environment》2010,408(20):4524-4531
To understand the potential threat of volatile organic compounds (VOCs) to the health of residents living close to a heavily polluted river, this study investigated the species and the concentration of VOCs evaporating from a river and surveyed the health condition of the nearby residents. Air samples were taken seasonally at the upstream, midstream, and downstream water surfaces of the river, and at different locations at certain distances from the river. These samples were analyzed qualitatively and quantitatively through gas chromatography and electron capture detector (GC/ECD) for chlorinated organic compounds, and through gas chromatography and flame ionization detector (GC/FID) for ordinary hydrocarbons. The health data obtained from valid health questionnaires of 908 residents were analyzed through Statistical Package for Social Science (SPSS) software. Twenty-six species of VOCs were identified in the environment adjacent the river, many of which are carcinogenic or believed to be carcinogenic to humans. However, results of this study shows that the VOCs evaporating from the polluted river have not been definitively identified as a major factor of cancer in the residents. However, the risk of suffering from certain chronic diseases may increase in residents living less than 225 m away from the river due to the high levels of evaporated VOCs. Residents living less than 225 m away from the river and with nearby specific industries are 3.130 times more at risk of suffering from chronic diseases than those with no nearby specific industries. 相似文献
55.
在探索意大利波河平原城市发展历史的基础上,试图在重要的历史时期中找出那些对城市发展产生过影响的事件,并通过案例的研究找出这些历史的种子在今天城市结构中的痕迹。以此作为未来对波河平原和珠江三角洲进行比较研究的开篇。 相似文献
56.
利用星载ERS-2 SAR进行长江口海面风场反演研究 总被引:1,自引:0,他引:1
基于SAR图像反演原理,提出一种后向散射系数反演海面风场的新方法,以相关长度确定风向,再利用随机粗糙海面理论模型反演风速.并以ERS-2 SAR为数据源,以长江口海区为研究区,获取了海面风场,反演结果和浮标测量风场对比,相符得很好,证明了该方法的可行性。 相似文献
57.
本文基于多光谱遥感图像,提出了一种融合光谱特征和空间信息的主溜特征提取方法.将遥感影像的两大表现形式--光谱和空间信息结合,利用像元及其邻域的关系来描述其空间结构,用方向线来描述黄河主溜,从而确定其位置和走向.实验结果表明,该方法可有效地提取出黄河主溜特征. 相似文献
58.
Most of the rivers in Taiwan are short and run on a steep slope due to the island's topography. Because of the weak correlations of streamflow in time and the occurrence of extreme events such as typhoons, classical autoregressive-moving average (ARMA) models have difficulties in forecasting and synthesizing the average 10-day streamflow in Taiwan. In this study, the synthesis of the average 10-day streamflow of the Tanshui River in Taiwan is accomplished by a section model. The model divides the year-round streamflow records into several sections according to their distinguishable patterns, and each section is modeled by a separate ARMA model. For parameter control, a heuristic grouping procedure, based on statistical inference of the random noise part, is used to separate a year into a minimum number of sections. The section separation procedure follows the general precipitation pattern in a year. The case study results indicate high statistical agreement between synthesized series and historical records. Additionally, a new procedure, extended autocorrelation function (EACF), is introduced and applied in this study to assist in model identification. 相似文献
59.
黄河口清水沟行水年限的计算 总被引:1,自引:0,他引:1
八十年代中,人们提出黄河口应该改道了,报到中央,引起很大震动,报经作者研究,发现当时河口大堤防御水位尚有2m富余,河道比降也偏大较多,不必改道,以河道防洪条件作为改道标准,过去并不明确,作者进而用5种方法计算,得到河口还可以使用50年,不必加高河口大堤,而且都加了较大的安全系数,计算考虑了不能淤坏小清河口的问题,还进行了河口液次淤积延伸,附近潮汐因素依次变化的数学计算,没有发现有较大的不良影响。 相似文献
60.
黄河水资源利用现状,预测及对策 总被引:1,自引:0,他引:1
人民治黄以来,黄河流域修建了大量的蓄,引,提水工程,为黄河水资源的开发利用创造了良好的条件,1990年流域工农业总引用水478亿m^3其中地下水114亿m^3,河川水364亿m^3,用水量最多的是农业灌溉,工业及生活用水比重较小,据分析,2000年水平全流域总需水量640亿m^3年供水量为620亿m^3,缺水20亿m^3,2010年水平全流域总需水量为723亿m^3,在满足下游输水入海用水条件下, 相似文献