全文获取类型
收费全文 | 9982篇 |
免费 | 1289篇 |
国内免费 | 800篇 |
专业分类
电工技术 | 460篇 |
技术理论 | 2篇 |
综合类 | 1233篇 |
化学工业 | 639篇 |
金属工艺 | 449篇 |
机械仪表 | 715篇 |
建筑科学 | 1330篇 |
矿业工程 | 684篇 |
能源动力 | 302篇 |
轻工业 | 312篇 |
水利工程 | 804篇 |
石油天然气 | 990篇 |
武器工业 | 176篇 |
无线电 | 878篇 |
一般工业技术 | 919篇 |
冶金工业 | 363篇 |
原子能技术 | 118篇 |
自动化技术 | 1697篇 |
出版年
2024年 | 31篇 |
2023年 | 148篇 |
2022年 | 326篇 |
2021年 | 335篇 |
2020年 | 377篇 |
2019年 | 364篇 |
2018年 | 328篇 |
2017年 | 366篇 |
2016年 | 446篇 |
2015年 | 464篇 |
2014年 | 618篇 |
2013年 | 621篇 |
2012年 | 715篇 |
2011年 | 749篇 |
2010年 | 515篇 |
2009年 | 525篇 |
2008年 | 510篇 |
2007年 | 646篇 |
2006年 | 592篇 |
2005年 | 501篇 |
2004年 | 434篇 |
2003年 | 367篇 |
2002年 | 324篇 |
2001年 | 283篇 |
2000年 | 240篇 |
1999年 | 194篇 |
1998年 | 179篇 |
1997年 | 132篇 |
1996年 | 132篇 |
1995年 | 121篇 |
1994年 | 105篇 |
1993年 | 61篇 |
1992年 | 57篇 |
1991年 | 47篇 |
1990年 | 40篇 |
1989年 | 33篇 |
1988年 | 21篇 |
1987年 | 13篇 |
1986年 | 16篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1978年 | 3篇 |
1964年 | 4篇 |
1962年 | 3篇 |
1957年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
汪健元 《中国有色金属学报》1996,6(2):141-145
探讨了回顶法灌注混凝土浆的成桩工艺,分析了影响混凝土浆灌注质量的主要因素,并给出了相应的技术参数和措施。 相似文献
22.
在对Sirius叠前深度偏移软件应用开发的基础上,分析讨论了Sirius 2D叠前深度偏移速度模型建立、层析成像及演、叠前深度偏移以及深度聚焦等技术环节的基本原理,并以莺歌海盆地某测线的处理为例,具体分析了Sirius 2D叠前深度偏移处理的流程、主要参数及时效.文中还分析讨论了莺歌海盆地中央“泥拱带”叠前深度偏移处理的地质效果.实践表明,莺歌海盆地广泛发育的与“泥拱模糊带”有关的构造各有其特殊性,只有通过3D叠前深度偏移处理才能从根本上解决“泥拱模糊带”的成像问题. 相似文献
23.
24.
Dimitrios Tzovaras Nikos Grammalidis Michael G. Strintzis 《Signal Processing: Image Communication》1998,11(3):205-230
In the present paper techniques are examined for the coding of the depth map and disparity fields for stereo or multiview image communication applications. It is assumed that both the left and right channels of the multiview image sequence are coded using block- or object-based methods. A dynamic programming algorithm is used to estimate a disparity field between each stereo image pair. Depth is then estimated and occlusions are optionally detected, based on the estimated disparity fields. Spatial interpolation techniques are examined based on the disparity/depth information and the detection of occluded regions using either stereoscopic or trinocular camera configurations. It is seen that the presence of a third camera at the transmitter site improves the estimation of disparities, the detection of occlusions and the accuracy of the resulting spatial interpolation at the receiver. Various disparity field and depth map coding techniques are then proposed and evaluated, with emphasis given to the quality of the resulting intermediate images at the receiver site. Block-based and wireframe modeling techniques are examined for the coding of isolated depth or disparity map information. Further, 2D and 3D motion compensation techniques are evaluated for the coding of sequences of depth or disparity maps. The motion fields needed may be available as a byproduct of block-based or object-based coding of the intensity images. Experimental results are given for the evaluation of the performance of the proposed coding and spatial interpolation methods. 相似文献
25.
26.
27.
Kazi Md. Shorowordi Md. Mohar Ali Bepari 《Journal of Materials Engineering and Performance》2002,11(6):625-630
Carbon (0.13%) steel samples containing about 0.48% molybdenum (Mo) singly and in combination with nickel (Ni) were carburized in a natural Titas gas atmosphere at a temperature of 1223 K (950 °C) and at a pressure of about 0.10 MPa (15 psia) for time periods ranging from 1–4 h followed by slow cooling in the furnace. Their microstructure was studied by optical microscopy. The austenite grain size of the case and the case depths were determined. It was found that Mo and Ni alone and in combination decrease the thickness of the cementite network near the surface of the carburized case of the steels. However, Ni is found to be more effective than Mo in decreasing the thickness of cementite network. Both Mo and Ni enhance the formation of Widmanstätten cementite plates at the grain boundary and within the grains near the surface of the carburized steels. However, Ni alone is more effective than Mo in the formation of Widmanstätten cementite plates. In the presence of Ni, Mo is much more effective in the formation of Widmanstätten cementite plates than Mo in absence of Ni. It was also revealed that both Mo and Ni increased the case depth. Ni is more effective than Mo in increasing the case depth. The combined effect of Mo and Ni is much greater than that of either Mo or Ni alone in increasing case depth. Mo as Mo carbide (Mo2C) particles refined the austenite grain size of the carburized case. Ni in solution was not found to have any effect in restricting grain growth of austenite, but the presence of Ni enhances the austenite grain size refining effect of Mo in the carburized case. 相似文献
28.
29.
2003年11月龙滩工程将实现大江截流,随着工程建设的全面推进,越发显出实施龙滩水电站正常蓄水位400m一次建成方案的重要性和紧迫性。相对分期建设而言,400m水位一次建成,工程效益大、增加投资少、无后期加高过程中的各种技术难题,基本不影响电站的初期发电效益,水轮机设计与运行问题少、机组运行条件好,电站规模效益与社会综合效益巨大,有利于移民安置和库区经济的发展,对国家、地方、企业均十分有利,因此应尽快决策实施400m一次建成方案。 相似文献
30.