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1.
Mauro Zammarano John R. Shields Isaac Leventon Ickchan Kim Shonali Nazare Andre Thompson Rick D. Davis Artur Chernovsky Matthew Bundy 《火与材料》2021,45(1):114-126
Herein, we describe a reduced‐scale test (“Cube” test), measuring the fire performance of specimens including a fire barrier (FB) and a flammable core material, which acts as the main fuel load. The specimen is intended to reproduce a cross‐section of a composite product where heat/mass transfer occurs primarily in a direction perpendicular to the FB. The Cube test procedure and benefits are discussed in this work by adopting residential upholstery furniture as an exemplary study. One flexible polyurethane foam, one polypropylene cover fabric, and 10 commercially available FBs were selected. They were used to compare the fire performance of FBs, measured in terms of peak of heat release rate, in the ASTM E1474‐14 standard test and the newly developed Cube test. Edge effects severely affected the performance of FBs in the ASTM E1474‐14 standard test but not in the Cube test. Furthermore, appropriate test conditions were determined in the Cube test to measure the so‐called “wetting point,” that is, the time and value of heat release rate measured when flammable liquid products were first observed on the bottom of the specimen. The relevance of the “wetting point” in terms of full‐scale fire performance and failure mechanism of FBs is discussed. 相似文献
2.
William M. Pitts Martin Werrel Marco Fernandez Mary A. Long Evan A. Eisenberg James Filliben Cory D. Runyon 《火与材料》2021,45(1):127-154
Fire spread and growth on real‐scale four cushion mock‐ups of residential upholstered furniture (RUF) were investigated with the goal of identifying whether changes in five classes of materials (barrier, flexible polyurethane foam, polyester fiber wrap, upholstery fabric, and sewing thread), referred to as factors, resulted in statistically significant changes in burning behavior. A fractional factorial experimental design plus practical considerations yielded a test matrix with 20 material combinations. Experiments were repeated a minimum of two times. Measurements included fire spread rates derived from video recordings and heat release rates (HRRs). A total of 13 experimental parameters (3 based on the videos and 10 on the HRR results), referred to as responses, characterized the measurements. Statistical analyses based on Main Effects Plots (main effects) and Block Plots (main effects and factor interactions) were used. The results showed that three of the factors resulted in statistically significant effects on varying numbers of the 13 responses. The Barrier and Fabric factors had the strongest main effects with roughly comparable magnitudes. Foam was statistically significant for fewer of the responses and its overall strength was weaker than for Barrier and Fabric. No statistically significant main effects were identified for Wrap or Thread. Multiple two‐term interactions between factors were identified as being statistically significant. The Barrier*Fabric interaction resulted in the highest number of and strongest statistically significant effects. The existence of two‐term interactions means that it will be necessary to consider their effects in approaches designed to predict the burning behavior of RUF. 相似文献
3.
城市街道作为城市最重要的活动空间,对其进行合
理的规划和改造有利于改善城市热环境。揭示街道可视因子对
街道峡谷微气候和热舒适度的作用机制,可以作为城市规划设
计的理论基础。选取杭州市典型街道峡谷为研究对象,通过
实测和数据分析发现,在夏季午后,不同街道峡谷内微气候和
热舒适度存在明显差异:各街道峡谷之间空气温度、平均辐
射温度和生理等效温度最大值与最小值之差分别达到了2.9、
25.3和15.3℃;N-S朝向的街道热环境优于E-W朝向的街
道,但街道的开敞程度和植物遮阴会抵消街道朝向的影响。研
究也发现,在午后,街道可视因子会对街道峡谷热环境产生不
同程度的影响,天空可视因子越高,街道峡谷空间越开敞,街
道热环境和热舒适度越差;建筑可视因子与城市街道峡谷微气
候和热舒适度相关性不大;而树木可视因子则对街道峡谷热环
境具有重要影响,树木可视因子越高,街道树木的遮阴程度越
高,街道内热环境和热舒适度越佳,这种现象在E-W朝向的
街道峡谷中表现得更为明显。 相似文献
4.
为科学指导室内装饰装修选材,以实现对室内装饰装修项目完工后室内环境中甲醛有效的控制,本文重点研究了国内外应用气候舱法测量木质家具中甲醛释放量的相关检测标准,并在此基础上探讨了影响甲醛释放的相关环境因素,从而得出根据小型气候舱测试木制家具系统各组件甲醛释放量结果推算木制家具早期投入使用时室内甲醛浓度参数的计算模型,为木制家具甲醛测试方法的应用与工程选材提供了参考。 相似文献
5.
6.
University students spend most of their time in classrooms, mostly in a sitting position. Prolonged sitting on ill-fitted furniture and the resulting bad posture is making students suffer from different musculoskeletal disorders (MSDs). This study evaluates the potential mismatch between furniture dimensions and anthropometric measurements. To determine potential mismatch, 13 anthropometric measurements of 550 students and 11 dimensions of two types of classroom furniture (mounted-desktop and chair-with-table) were measured and then compared. Additionally, chi-square test was performed to compare the relation between anthropometry and relevant furniture dimensions. Results showed that a significant number of mismatches emerged between anthropometric measurements and furniture dimensions. For both types of furniture, seat height was too high and seat depth was too deep. Moreover, for mounted desktop, desk height is almost appropriate for all students whereas for chair and table, it was too high for the males. These circumstances may lead to increase discomfort and increase MSDs problems among all students. It can be concluded that the dimensions of both types of classroom furniture were not appropriate for users according to anthropometric measurements. This analysis recommends the measurements of furniture dimensions based on participants’ anthropometric measurements to avoid or minimise discomfort and MSDs problems. 相似文献
7.
在文献基础上梳理了街道安全感影响因素,并采用上海样本检验了"街道眼"等西方街道安全理论。邀请30位学生和30位市民对上海5个不同发展时期社区的300张百度街景图片进行安全感评定。实验发现绿视率、管理程度、车道数等都对安全感起着显著作用,并分别建立了单双车道和多车道街道空间的安全感回归模型。其中发现绿视率(单双车道相关系数R=0.728,p0.01;多车道相关系数R=0.471,p0.01)、管理程度(单双车道相关系数R=0.766,p0.01;多车道相关系数R=0.450,p0.01)、车道数量因素(相关系数R=0.502,p0.01)对安全感均有显著的积极作用,界面透明度(单双车道相关系数R=0.222,p0.01)、独立自行车道(相关系数R=0.309,p0.01)及设计美感(相关系数R=0.432,p0.01)等因素在单双车道空间中具有积极影响,而助动车与自行车(单双车道相关系数R=-0.327,p0.01;多车道相关系数R=-0.281,p0.01)在对安全感知评价具有消极影响,机动车(单双车道相关系数R=0.251,p0.01;多车道相关系数R=-0.327,p0.01)在单双车道与多车道空间中呈现相反的作用。 相似文献
8.
摘要 随着城市建设提质优化以及人们对美好生活的追求,空间品质成为城市研究中的重要组成部分。但近年来经济
的高速发展,城市空间出现失序。以合肥市二环内区域为案例,以街景图像等多源数据为载体,采用非现场建成环境
审计等技术方法,探索合肥市空间失序现象以及不同类型的街道与空间失序程度的关系。结果表明合肥市二环内:(1)
整体空间破败程度为35.11%;(2)空间失序要素中以沿街商业要素的失序程度最为严重;(3)商业服务业设施用
地街道(B 类)空间品质最差,物流仓储用地(W 类)街道空间品质优质。基于空间失序理论,大规模测度街道空间
品质的优劣,在实践上能为未来城市的精细化管理提供重要依据;在理论研究上尝试弥补以往国内城市地理对空间失
序研究的空缺。 相似文献
9.
摘要 地铁站作为城市重要的交通节点,在发达城市商业中心区的站点多与周边商业建筑地下空间相互连通,为城市
核心商业区输送大量的步行人流,从而带来更多商业机遇。选取我国典型中心商业区地铁开发模式的广州北京路商圈
及其附近的公园前地铁站为例,通过实地调研测量统计步行人流量、轨迹等数据,运用行为模拟、空间分析等方法,
讨论公园前地铁站域的地下空间建设对北京路商圈地面人流的再分配作用,进而分析地铁站各地面出入口的商业表现、
服务范围与功能,对该站点建设之于商业发展的促进作用做出初步评估。通过对公园前地铁站域以及其主要服务的北
京路商业区的案例深入解读,希望为其他城市传统中心商业区的站点交通发展或新开发提供借鉴。 相似文献
10.
城市景观是一种具有多感官价值的社会公共资源,但因其视觉等维度的公平性难以量化,景观公平性研究多集中于资源的合理配置和居民可达性等方向。尝试通过街道景观对路权冲突的补偿作用,来衡量其视觉公平性。研究将街道环境使用者在遭遇路权冲突时引发的情绪反应作为表征,量化街景补偿作用,从而建立街景元素、视觉补偿以及路权冲突三者之间的关系。通过问卷调查与情景模拟的方法识别上海市研究范围内的街景,呈现出两类明显不同的补偿作用:正向补偿与负向补偿。其中,在正向补偿型街景中,天空、绿植等街景元素与开阔度、一致性等景观特性对于缓解因路权冲突引起的愤怒情绪具有显著作用。此外,还发现上海市不同区域低等级街道的街景补偿作用在不同使用者群体之间具有偏向性。因此,提出从街景补偿角度对城市低等级街道进行分类,以街景补偿对使用者情绪的影响,缓解使用者之间固有的不公平性,减少冲突,改善街道使用者的心理健康水平,保证街道环境安全。 相似文献