全文获取类型
收费全文 | 14490篇 |
免费 | 1614篇 |
国内免费 | 817篇 |
专业分类
电工技术 | 1467篇 |
综合类 | 1609篇 |
化学工业 | 1508篇 |
金属工艺 | 933篇 |
机械仪表 | 1824篇 |
建筑科学 | 1085篇 |
矿业工程 | 993篇 |
能源动力 | 662篇 |
轻工业 | 466篇 |
水利工程 | 338篇 |
石油天然气 | 608篇 |
武器工业 | 461篇 |
无线电 | 1703篇 |
一般工业技术 | 1426篇 |
冶金工业 | 430篇 |
原子能技术 | 147篇 |
自动化技术 | 1261篇 |
出版年
2024年 | 78篇 |
2023年 | 206篇 |
2022年 | 366篇 |
2021年 | 437篇 |
2020年 | 507篇 |
2019年 | 423篇 |
2018年 | 455篇 |
2017年 | 594篇 |
2016年 | 620篇 |
2015年 | 621篇 |
2014年 | 974篇 |
2013年 | 987篇 |
2012年 | 1130篇 |
2011年 | 1110篇 |
2010年 | 871篇 |
2009年 | 877篇 |
2008年 | 771篇 |
2007年 | 921篇 |
2006年 | 802篇 |
2005年 | 635篇 |
2004年 | 523篇 |
2003年 | 461篇 |
2002年 | 369篇 |
2001年 | 372篇 |
2000年 | 289篇 |
1999年 | 257篇 |
1998年 | 203篇 |
1997年 | 223篇 |
1996年 | 164篇 |
1995年 | 150篇 |
1994年 | 117篇 |
1993年 | 88篇 |
1992年 | 71篇 |
1991年 | 56篇 |
1990年 | 38篇 |
1989年 | 38篇 |
1988年 | 33篇 |
1987年 | 23篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1959年 | 3篇 |
1958年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
矿用圆环链弯曲点的角度分布 总被引:2,自引:1,他引:1
矿用圆环链弯曲点是应力集中点 ,肩部断裂发生于该点附近 .以 2 6× 92矿用圆环链为研究对象 ,应用方向数据统计导出该点的角度分布 ,并给出了批量检验矿用圆环链尺寸匹配状况的一种方法 相似文献
42.
Masahide Hojo Yasunori Mitani Toshifumi Ise Kiichiro Tsuji 《Electrical Engineering in Japan》2002,138(3):43-51
The advancement of power electronics technologies has significantly developed the power system stabilizing controllers. Quantitative as well as qualitative evaluation of their effectiveness in power systems is a matter of great importance for the feasibility investigation of these apparatus. In this paper, the possible control region of FACTS controllers with series and/or shunt configuration in a single machine to infinite bus system is formulated in the powerangle curve with a set of algebraic equations. The effectiveness of TCPST (Thyristor‐Controlled Phase Shifting Transformer), SSSC (Static Synchronous Series Compensator), and TCSC (Thyristor‐Controlled Series Compensator) for the improvement of the transient stability is evaluated quantitatively as a numerical example. The correctness of the proposed method has been confirmed by analysis based on the electromagnetic transients simulation with a detailed system model. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 43–51, 2002 相似文献
43.
44.
45.
46.
Relative grain boundary energies can be simply related to true dihedral angles, which are the angles between grain boundary planes meeting at triple edges in polycrystals. Some limited efforts in the measurement of true dihedral angles have used the technique of serial sectioning, which is usually cumbersome and time consuming. In this study the three‐dimensional probe called the ‘disector’ has been employed to evaluate true dihedral angles. This probe, combined with automated image processing, introduces precision as well as efficiency, overcomes the disadvantages of the two‐dimensional probe and is far less tedious and less complicated than serial sectioning. It is shown that the technique is relatively simple and therefore can be applied to obtain a significantly large and accurate statistical sample of true dihedral angles. The application of this method is demonstrated by evaluating the triple junction geometry and the associated relative grain boundary energies in polycrystalline 316L austenitic stainless steel. 相似文献
47.
The grafting of acrylic acid onto electron beam‐irradiated polypropylene was carried out using preirradiation method. The stability of peroxy radicals was investigated by electron spin resonance. It was found that the decay of peroxy radicals is much faster at 70°C than at 40°C and ambient temperature. The grafting has been observed to be strongly dependent on the monomer dilution in the reaction medium. The grafting was ascertained by attenuated total reflectance (ATR). The distribution of grafts across the samples was monitored by infrared microscopy. It was found that the graft management is considerably influenced by composition of the grafting medium. The grafting involving pure monomer leads to the surface enrichment with the polyacrylic acid chains. The samples grafted in pure monomer led to much lower contact angles as compared to the diluted monomer solution. The swelling of the grafted samples also showed a trend that was governed by the graft management. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 546–553, 2006 相似文献
48.
49.
提出了基于AutoCAD2 0 0 0的图解法求解机械加工过程中工艺转角的问题 ,并针对具体的应用实例给出了圆满的解答 ,并验证了其精度。 相似文献
50.
介绍了一种新型悬臂棒条筛分机械,论述了其结构、工作原理和技术特性。从理论和实践两方面论证了它的结构、处理能力、筛分效率、返矿率都明显优于普通悬臂棒条筛分机械,可广泛应用于高炉槽下烧结矿的筛分作业。 相似文献