全文获取类型
收费全文 | 24807篇 |
免费 | 2037篇 |
国内免费 | 1233篇 |
专业分类
电工技术 | 4023篇 |
综合类 | 2688篇 |
化学工业 | 1849篇 |
金属工艺 | 870篇 |
机械仪表 | 1561篇 |
建筑科学 | 2741篇 |
矿业工程 | 852篇 |
能源动力 | 562篇 |
轻工业 | 795篇 |
水利工程 | 711篇 |
石油天然气 | 556篇 |
武器工业 | 222篇 |
无线电 | 4203篇 |
一般工业技术 | 1453篇 |
冶金工业 | 1004篇 |
原子能技术 | 218篇 |
自动化技术 | 3769篇 |
出版年
2024年 | 75篇 |
2023年 | 176篇 |
2022年 | 338篇 |
2021年 | 440篇 |
2020年 | 436篇 |
2019年 | 353篇 |
2018年 | 335篇 |
2017年 | 519篇 |
2016年 | 624篇 |
2015年 | 705篇 |
2014年 | 1446篇 |
2013年 | 1143篇 |
2012年 | 1645篇 |
2011年 | 1827篇 |
2010年 | 1514篇 |
2009年 | 1537篇 |
2008年 | 1596篇 |
2007年 | 1928篇 |
2006年 | 1803篇 |
2005年 | 1534篇 |
2004年 | 1410篇 |
2003年 | 1298篇 |
2002年 | 1123篇 |
2001年 | 915篇 |
2000年 | 690篇 |
1999年 | 583篇 |
1998年 | 411篇 |
1997年 | 314篇 |
1996年 | 265篇 |
1995年 | 190篇 |
1994年 | 162篇 |
1993年 | 139篇 |
1992年 | 123篇 |
1991年 | 81篇 |
1990年 | 81篇 |
1989年 | 65篇 |
1988年 | 52篇 |
1987年 | 30篇 |
1986年 | 29篇 |
1985年 | 20篇 |
1984年 | 22篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1973年 | 5篇 |
1968年 | 6篇 |
1966年 | 4篇 |
1958年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
万华炜 《湖北工业大学学报》2009,24(6):1-3
充分发挥市场在资源配置上的基础性作用和政府对经济的宏观调控职能是实现经济要又好又快发展必然要求.政府对经济的宏观调控,必须遵循以科学发展观为指导,以社会主义初级阶段的基本国情为出发点,以以人为本为根本导向,以实现经济可持续协调发展为根本目标,以多种调控手段统筹兼顾为基本方法,以市场为基础,以政府公共管理为中心,以国家发展规划、计划、产业政策为导向,以财政、货币政策、法律为手段的基本原则. 相似文献
32.
谢廷东 《四川轻化工学院学报》2010,(3):257-259
云南省永善县云荞水库自建成蓄水以来运行良好,2008年5月12日,四川省汶川县发生8.0级地震,云荞水库震感强烈,水库内水浪约1.0m高,水库受损,面板裂缝加大;震后云荞水库工程管理局高度重视云荞水库的安全问题,特请某水利水电勘测设计研究院对面板进行健全性检测,管理局根据检查单位对大坝面板的整体性能做出的评价及提出相应的处理意见,对面板裂缝进行了化学灌浆和表面封闭处理,至今运行良好。 相似文献
33.
Recently, it has been reported by our group and others1.2 that loss of curing agent is encountered during the curing of small droplets or thin films of amine cured epoxies. In our earlier study3 results were reported on loss of curing agent in small droplets used in conducting the rnicrobond, single fiber test for determination of interfacial shear strength (ISS). It was reported that use of a volatile curing agent (meta-phenylene diamine (m-PDA) with DGEBA resin) resulted in increasing amounts of curing agent being lost (as measured by T8 of the cured droplets) with decreasing droplet size during the processing procedure. Droplets smaller than 150 micrometers were seen to lose up to 40% of the curing agent leading to alteration of the mechanical properties of the droplet and, therefore, causing measured values of ISS to be exceedingly low. Use of a less volatile curing agent (Jeffamine 700, a polyether diamine, Texaco Specialty Chemicals) in combination with DGEBA resin produced results which indicated that loss of curing agent was not occuring. This study was undertaken to show the relationships between film (or droplet) size and the amount of curing agent lost (during the processing) for three different aminecured epoxy systems. 相似文献
34.
The object of the present study was to investigate the effect of superimposed dynamic and static stresses on mechanical and thermal properties of some epoxy adhesives. It was found that combinations of shear creep and torsional oscillations, applied simultaneously to adhesive joints at temperatures within the glassy range of the adhesive, led to strengthening of the joints in shear and to an increase in the glass transition temperature of the adhesive. Similar loading stresses applied at temperatures close to the Tg of the adhesive, led to opposite effects on the above mentioned properties of the joints. The width of the glassy-rubbery transition of the adhesives increased, in the whole range of temperatures used in this study and for all epoxy compositions, as a result of subjecting the joints to superimposed dynamic and static stresses. The broadening of the glass transition was interpreted as a result of the stiffening of polymer network during the combined stressing experiments. A linear relationship was found between the area of endothermal peaks in the first DSC scan of specimens subjected prior to test to superimposed dynamic and static stresses at temperatures below Tg, and the shear strength of the joints. In agreement with this observation and with literature data, a linear relationship was revealed also between the glass transition temperature of the resins (measured in the first DSC scan) and the shear strength of the joints. Based on experimental observations and on some literature information, it was suggested that the strengthening of the joint, as well as the changes in thermal properties of the adhesives, are mainly due to physical processes, such as short-range orientation of network chains and an increase in intermolecular interaction between highly polar sites of the network. The possibility that superimposed stressing led to changes in chemical crosslinking was discussed but it seems that no such reactions occurred. 相似文献
35.
The effect of the temperature of gas phase CO upon the kinetics of the oxygen titration reaction: COg +Oa CO2,g, has been studied. It is found that the reaction's rate is independant of CO gas temperature between 300 and 623 K. The activation energy (6.5 kcal/mole), dependence upon CO pressure (first-order), and independence upon oxygen coverage for 0.1 o 0.4 are all independant of the CO gas phase temperature. This result rules out any Eley-Rideal type mechanism whereby CO reacts directly from the gas phase with an oxygen adatom without first being accommodated to the surface temperature in an absorbed state. The result is instead interpretable in terms of a Langmuir-Hinshelwood mechanism.Camille and Henry Dreyfus Foundation Teacher-Scholar Fellowship. 相似文献
36.
赵国林 《吉林化工学院学报》2015,(7)
民办高校有着与公办高校不同的管理体制和机制,为了更加深入、更加有效地开展党的群众路线教育实践活动,要结合特点和发展的实际,科学制定活动方案、强化针对性,真正解决工作中存在的问题,正确地处理几个共性问题,有效凝聚学校发展的力量,推动中国高等教育事业全面健康可持续发展。 相似文献
37.
刘军丽 《四川烹饪高等专科学校学报》2014,(1):12-15
文人茶是中国茶文化体系中具有独立品格与内涵的茶文化模式,也代表着中国茶文化的最高层次。明代中期以后,文人们推崇饮茶“天趣悉备”的自然美,许多文人更是全身心投入到茶事活动中,将茶事品茗作为表达志向与修身养性的主要方式,茶诗创作成果丰硕。茶诗的创作是一种文学现象,极大地丰富了茶文化的表现形态与内涵。明代茶诗体现出明代文人茶虚静空灵、天人合一以及本真自然、闲适清逸的艺术精神。 相似文献
38.
C. Cagran B. Wilthan G. Pottlacher B. Roebuck M. Wickins R. A. Harding 《Intermetallics》2003,11(11-12):1327
The families of titanium aluminide intermetallic alloys have attractive high temperature mechanical properties which make them potential candidate materials for a wide range of applications, particularly in the aeronautic and automobile sectors. The development of appropriate manufacturing techniques is an essential stage in the engineering exploitation of these materials, e.g., Induction Skull Melting is one of the techniques which needs to be optimised for the casting of titanium aluminides. Research is underway to develop a computer model of this process but data are required for the key thermophysical properties. Pulse-heating techniques have been used to measure properties for the Ti–44Al–8Nb–1B system. Rectangular samples have been prepared and are resistively heated as part of a fast capacitor discharge circuit. Time-resolved measurements with sub-μs resolution of currents through the specimen were made with a Pearson probe current monitor using the induction principle. Voltages across the specimen were determined with knife-edge contacts and voltage dividers, and radiance temperatures of the sample were measured with a pyrometer. These measurements allow the calculation of specific heat and dependencies between enthalpy, electrical resistivity and temperature of the alloy up into the liquid phase. Data for thermal diffusivity have been obtained by using the Wiedeman–Franz relation. The results are compared with those obtained using DSC and the four-probe method to measure the temperature dependence of the resistivity. 相似文献
39.
40.