全文获取类型
收费全文 | 13406篇 |
免费 | 1273篇 |
国内免费 | 513篇 |
专业分类
电工技术 | 222篇 |
综合类 | 787篇 |
化学工业 | 2811篇 |
金属工艺 | 1339篇 |
机械仪表 | 413篇 |
建筑科学 | 814篇 |
矿业工程 | 771篇 |
能源动力 | 394篇 |
轻工业 | 949篇 |
水利工程 | 350篇 |
石油天然气 | 2597篇 |
武器工业 | 58篇 |
无线电 | 304篇 |
一般工业技术 | 1308篇 |
冶金工业 | 1557篇 |
原子能技术 | 307篇 |
自动化技术 | 211篇 |
出版年
2024年 | 56篇 |
2023年 | 250篇 |
2022年 | 377篇 |
2021年 | 494篇 |
2020年 | 535篇 |
2019年 | 438篇 |
2018年 | 394篇 |
2017年 | 413篇 |
2016年 | 496篇 |
2015年 | 468篇 |
2014年 | 762篇 |
2013年 | 1029篇 |
2012年 | 1061篇 |
2011年 | 1009篇 |
2010年 | 715篇 |
2009年 | 649篇 |
2008年 | 579篇 |
2007年 | 753篇 |
2006年 | 708篇 |
2005年 | 604篇 |
2004年 | 507篇 |
2003年 | 461篇 |
2002年 | 435篇 |
2001年 | 312篇 |
2000年 | 301篇 |
1999年 | 272篇 |
1998年 | 197篇 |
1997年 | 150篇 |
1996年 | 147篇 |
1995年 | 121篇 |
1994年 | 82篇 |
1993年 | 57篇 |
1992年 | 69篇 |
1991年 | 56篇 |
1990年 | 47篇 |
1989年 | 32篇 |
1988年 | 11篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 33篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 9篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1975年 | 6篇 |
1959年 | 2篇 |
1958年 | 1篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
本文探讨了影响中厚板厚度波动的因素,结合安钢中板厂2800mm轧机按合同轧制一批交货重量不大于理论重量船板的生产实践,总结了实际生产中实现高精度厚度控制的有效方法。 相似文献
22.
The low melting point metallic tin powder or alloy of tin and lead was blended with polypropy-lene. A kind of in situ composite has been prepared. The variations of torque were studied when the composites were mixed in Haake torque rheogeniometer. By way of capillary extrusion, effects upon rheology of the in situ com-posites of the low melting point metals (LMPM) and coupling agent for their different variety and content, were investigated. From flow curves, the results indicate that in situ composites mixed with the LMPM are a kind of pseudoplastic fluid. If the LMPM were melted, the higher the content of the LMPM , the lower apparent viscosity of composites. Meanwhile, when the coupling agent is added into composites, the viscosity of composite will go up first and drop then. This shows that the LMPM have a promoter flow action on the polypropylene. 相似文献
23.
24.
Yoshinori Nakazawa 《Advanced Performance Materials》1995,2(4):369-384
MITI has actively done R&D on industrial technology for waste and reclamation and so there are many research items from small scale to large scale. However, Ecofactory and researches on recycling of metallic materials are introduced here. Ecofactory was proposed by the Mechanical Engineering Laboratory and is now at the stage of the Leading Research, a new research scheme in AISt. Researches on recycling of metallic materials are being done with subsidy. Those researches should contribute to both the preservatin of the global environment and effective recycling of waste materials.Abbreviations AIST
Agency of Industrial Science and Technology
- MITI
Ministry of International Trade and Industry
- NEDO
New Energy and Industrial Technology Development Organization 相似文献
25.
部分种子成分的特征X射线在等效生物材料中衰减的测定 总被引:6,自引:5,他引:1
用Si(Li)探测器实现了Na、Mg、S、Cl的特征X射线在有机膜中的相对衰减以及与O、K元素的特征X射线能量相当的X射线或轫致辐射在有机膜中的相对衰减,分别得出了它们减的数学描述,并把实验得到不同能量的X射线在有机膜中的质量吸收系数与Berkeley的OCG软件计算出的结果相比,相关都小于30%。 相似文献
26.
Wire-shaped zinc samples were resistively volume heated as part of a fast-capacitor discharge circuit. Time-resolved measurements with submicrosecond resolution of the current through the specimen, the voltage drop across it, and the thermal expansion of the specimen as a function of time allow determination of the enthalpy, electrical resistivity, and density at different temperatures up to superheated liquid states of zinc far above the normal boiling point. High static pressures, up to 3800 bar of the ambient medium water, were used. An estimate of the critical pressure for zinc is given by investigations of the stability of the sample with a framing CCD camera, taking pictures of different samples varying the ambient static pressure. The critical volume and the critical temperature are obtained by means of an extrapolation of measured data at different pressures.Paper presented at the Fourth International Workshop on Subsecond Thermophysics, June 27–29, 1995, Köln, Germany. 相似文献
27.
Y. Kraftmakher 《International Journal of Thermophysics》1994,15(5):983-991
Relaxation phenomena due to equilibration of point defects in metals are reviewed. The relaxation effect in specific heat observed in tungsten and platinum confirms that in both cases the nonlinear increase in the high-temperature specific heat has to be attributed to point-defect formation. Relaxation phenomena observed by measurements of electrical resistivity and positron annihilation are also considered. The comparison of the data seems to be favorable for the conclusion that all the phenomena are of one origin. 相似文献
28.
Sabha Kesraoui-Ouki Christopher R. Cheeseman Roger Perry 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(2):121-126
This paper assesses the potential of natural zeolite utilization as a low-cost ion-exchange and sorbent material in pollution control and recovery of metals. The improvement of the purity of natural zeolites coupled with their chemical modification capabilities in order to provide specific properties may provide a cost-effective alternative for the treatment of heavy metal contaminated soil and water. The application of natural zeolites in industrial pollution control is becoming important and the level of technical effort is increasingly expanding. The extent of application is unlikely to be related solely to their low cost, but also to improved properties and performance characteristics, which will advance the practical implementation of natural zeolites' technology. 相似文献
29.
30.