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排序方式: 共有175条查询结果,搜索用时 15 毫秒
1.
随着室内污染问题的日趋严重,我国室内空气污染状况、来源与危害及主要的防治措施也越来越受到关注。  相似文献   
2.
通过对LTE网络中高价值区域的识别与分析,可有效保证网络建设投资合理性、提升网络优化效率、节约各类资源投入。同时,高价值场景是中国移动“五高一地”重点关注的场景类型,但缺乏有效识别手段。本文通过LTE网络信令数据、MR数据、工参数据、经分数据等多维数据源关联分析,充分挖掘了数据价值,建立了价值评估体系,从经济价值和社会价值两个层面对网络发展情况进行多维度评估和分析,实现了高价值区域的聚合与自动生成,开展了区域价值分析,解决了高价值场景识别和规划优化工作中的痛点和难点问题,为提高规划优化投资效率提供了理论指导和技术支撑。  相似文献   
3.
Around the globe, intermittent renewable energies in the form of wind and solar power are on the rise. Their subsidization can be seen as a market intervention, which may deter optimal investment. Thus, this study tests the effect of renewable energies on investment in conventional electricity generation technologies. We estimate a dynamic investment model for 14 European economies for the period 2004–2016 and find a non-negligible negative impact of intermittent renewables on investment in peak-load capacity (mainly gas), while base-load (particularly coal) plants are unaffected. However, the production flexibility of gas-fired plants represents a particularly vital function to balance the supply intermittency of wind and solar. Thus, dispatchable conventional power plants are still necessary to back the system under scarcity events, such as unfavorable weather conditions during high electricity demand. Policymakers should be aware of the adverse effects of RES on investment in peak-load plants and may consider a redesign of the current system, for example by introducing capacity markets.  相似文献   
4.
The Flemish renewable electricity support system has struggled to address a number of problematic issues in the past. These included excessive profit margins and general malfunctioning of the green certificate market, as well as a lack of qualification of various existing renewable energy technologies. The Flemish government responded to these issues by introducing major reforms in 2013, including “banding” to differentiate the support for various technologies. However, reliable methods for differentiating renewable electricity technologies and calculating support levels have not been sufficiently developed. The main objective of the 2013 reforms was to reduce support costs, but application of German feed-in tariffs on 18 reference technologies has shown that most projects in Flanders continue to receive high levels of support. The 2013 reforms did not succeed in addressing malfunctioning of the green certificate market. On the contrary, the confidence of investors in renewable electricity plants has decreased as the terms of support can be altered retroactively by adjusting remuneration levels and through political interventions. Future adaptations are likely to be made which will further decrease the overall stability and effectiveness of the system.  相似文献   
5.
This study characterized indoor volatile organic compounds (VOCs) and investigated the effects of the dwelling characteristics, building materials, occupant activities, and environmental conditions on indoor VOC concentrations in 40 dwellings located in Melbourne, Australia, in 2008 and 2009. A total of 97 VOCs were identified. Nine VOCs, n‐butane, 2‐methylbutane, toluene, formaldehyde, acetaldehyde, d‐limonene, ethanol, 2‐propanol, and acetic acid, accounted for 68% of the sum of all VOCs. The median indoor concentrations of all VOCs were greater than those measured outdoors. The occupant density was positively associated with indoor VOC concentrations via occupant activities, including respiration and combustion. Terpenes were associated with the use of household cleaning and laundry products. A petroleum‐like indoor VOC signature of alkanes and aromatics was associated with the proximity of major roads. The indoor VOC concentrations were negatively correlated (P < 0.05) with ventilation. Levels of VOCs in these Australian dwellings were lower than those from previous studies in North America and Europe, probably due to a combination of an ongoing temporal decrease in indoor VOC concentrations and the leakier nature of Australian dwellings.  相似文献   
6.
基于互素对称阵的近场源定位   总被引:1,自引:0,他引:1  
针对近场源定位中存在的孔径损失问题,该文提出了一种新的近场源定位算法。该算法采用互素对称阵列,使得阵元间距不必限制于1/4信号波长。首先构造一个特殊的四阶累积量矩阵,进而采用MUSIC算法估计信源方位角,然后在每个估计方向上搜索距离。该算法将近场源2维定位问题转化为多次1维搜索,且参数自动配对。互素对称阵的使用有效地扩展了阵列孔径,提高了空间分辨概率和参数估计性能。计算机仿真验证了该算法的有效性。  相似文献   
7.
Facing increasing open innovation trends, Portuguese enterprises are considering the related processes and impacts. Thus, this work aims to identify the sectors whose enterprises most engage in open innovation (such as cooperation on this issue) and which sources/agents are most used. This is analyzed by sector and type of innovation as an interesting way of differentiation for better open innovation strategy delineation. Using the data from the Community Innovation Survey (CIS-2012), it first appraises the nature of the innovation process, either cooperative or firm-based, as the starting level of analysis. Then, it differentiates the results by sector illustrating which cooperation sources/agents are most used (scope) and relative intensity of use (scale). This is important to assess levels of openness and related factors. Results show that main innovating sectors in Portugal are of three types: research-based, knowledge-based and service-based. They reveal an increasing focus on knowledge and services, trends that have been leading to more active openness towards innovation. For instance, health and construction are increasing their openness for innovating and internationalizing processes. However, Portuguese innovation is still more firm-based (in-house) than cooperation-based, especially concerning new products' launching. This work and future analyzes around it can contribute to encourage the open innovation strategy in more sectors of the economy as an easy and effective way to cope with rapid trends and changes.  相似文献   
8.
介绍了乘客能量源的特点,调查了某学校附近城市公交车的营运状况,根据收集的乘客数据初步分析了乘客能量源的总量,为今后的相关研究工作提供参考。  相似文献   
9.
可吸入颗粒物严重影响空气质量和人体健康。国内外学者对可吸入颗粒物已经做了很多研究。探讨典型室内可吸入颗粒物的来源及其对人体健康的影响,并初步介绍了室内可吸入颗粒物的一些防治措施,以进一步提高室内空气品质。  相似文献   
10.
In order to investigate the pollution situation for a fast-developing industrial area at its first stage, a systematic study on the gaseous and particulate pollution in the Ordos Region of Inner Mongolia was performed during 9-24 September 2005. The gases SO2, NOx, O3, CO, and the particulates PM10 and PM2.5 were sampled at five sites in Ordos. Species measured in aerosol were 21 elements, 10 ions, organic carbon (OC), elemental carbon (EC), and the acid-buffering capacity of particulates. Possible markers of sources for different transport directions were firstly investigated, which was a new attempt for clarification of regional transport with different directions. None of the gases exceeded the national standards of China. PM2.5 contributed most to PM10 at the background site, indicating the greatest contribution of regional transport. Organic matter, crustal material, and sulfate ion were the three dominant species of aerosol, followed by EC, NO3, NH4+, trace elements, and other ions. The acidity of PM2.5 was higher than that of PM10, and the buffering capacity in PM10 was higher than that in PM2.5. Four peaks of pollution aerosol were observed during the 3-week study sampling period, separated by periods of cleaner air. Back-trajectories revealed that the peaks came from the south and the cleaner air from the north. It is the first time to find different markers for aerosols from different transport directions in Ordos. S and Pb, as well as SO42−, NO3, and NH4+ appeared to be good markers of southern aerosol in the Ordos, since all showed four clear peaks on days dominated by southern direction. Extremely high peaks of Al and Ti on the 16th and 17th, especially at the dust-monitoring site, indicated good markers for soil dust. Ca and Mg showed earlier peaks on the 16th at the western site, indicating possible markers for western aerosol.  相似文献   
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