全文获取类型
收费全文 | 26033篇 |
免费 | 1631篇 |
国内免费 | 2086篇 |
专业分类
电工技术 | 834篇 |
综合类 | 1437篇 |
化学工业 | 5553篇 |
金属工艺 | 3232篇 |
机械仪表 | 1924篇 |
建筑科学 | 311篇 |
矿业工程 | 178篇 |
能源动力 | 1236篇 |
轻工业 | 1749篇 |
水利工程 | 86篇 |
石油天然气 | 370篇 |
武器工业 | 122篇 |
无线电 | 4257篇 |
一般工业技术 | 6631篇 |
冶金工业 | 680篇 |
原子能技术 | 400篇 |
自动化技术 | 750篇 |
出版年
2024年 | 121篇 |
2023年 | 310篇 |
2022年 | 493篇 |
2021年 | 602篇 |
2020年 | 673篇 |
2019年 | 576篇 |
2018年 | 583篇 |
2017年 | 810篇 |
2016年 | 768篇 |
2015年 | 770篇 |
2014年 | 1103篇 |
2013年 | 1395篇 |
2012年 | 1550篇 |
2011年 | 2018篇 |
2010年 | 1457篇 |
2009年 | 1569篇 |
2008年 | 1402篇 |
2007年 | 1820篇 |
2006年 | 1706篇 |
2005年 | 1421篇 |
2004年 | 1313篇 |
2003年 | 1093篇 |
2002年 | 927篇 |
2001年 | 865篇 |
2000年 | 763篇 |
1999年 | 637篇 |
1998年 | 565篇 |
1997年 | 461篇 |
1996年 | 386篇 |
1995年 | 345篇 |
1994年 | 313篇 |
1993年 | 255篇 |
1992年 | 178篇 |
1991年 | 132篇 |
1990年 | 89篇 |
1989年 | 90篇 |
1988年 | 54篇 |
1987年 | 34篇 |
1986年 | 17篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1976年 | 3篇 |
1963年 | 3篇 |
1959年 | 5篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Songping Wu 《Materials Letters》2007,61(16):3526-3530
In this paper, non-agglomerated monodispersed ultra-fine copper metallic powders have been synthesized with chemical reduction method. Fine lead-free glass powders were also prepared by solid synthesis process. Thick film paste prepared by above-mentioned copper metallic powders and lead-free glass powders was applied as conductive paste of MLCC. Mixture of glass and zinc oxide give the thick film a high adhesion strength which is attributed to the rough interface from interfacial reaction between glass and chip, and a good densification. Diffusion of metal between copper thick film and nickel thick film is clear. Ni-Cu solid solution appears under high temperature firing. 相似文献
42.
Talita Moreira de Oliveira Nilda de Fátima Ferreira Soares Rodrigo Magela Pereira Kátia de Freitas Fraga 《Packaging Technology and Science》2007,20(2):147-153
Conservation of food products depends on product quality and packaging suitability. The objective of this work was to develop and evaluate the antimicrobial efficiency of natamycin‐incorporated film in the production process of Gorgonzola cheese. It aims to optimize the production process and increase shelf‐life and food safety for the consumer. Films with different concentrations of natamycin were produced and tested in Gorgonzola cheeses to evaluate its efficiency against Penicillium roqueforti on the cheese surface. Films with 2 and 4% natamycin presented satisfactory results for fungus inhibition and the amount of natamycin released to the cheese was below that allowed by the legislation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
43.
The exact magnetization pattern of magnetic films close to a spin-reorientation transition is difficult to analyze due to the intrinsically three-dimensional (3d) variation of the orientation of the local magnetization. We present a technique how this can be performed, based on the analysis of high quality 2d polarization maps from a single scanning electron microscope with polarization analysis (SEMPA) measurement with tilted sample. The key tool is the statistical distribution of all occurring polarization doublets, visualized in a 2d histogram plot. From the shape of the distribution the type of transition—canted-phase, or coexisting phases—can be inferred. For the canted-phase state, the canting angle can be accurately determined from geometrical considerations. With help of the histogram the image data can be analyzed and the three components of the magnetization can be calculated for most points of the image. For a Co/Pt multilayer film we found a cone state. The magnetization forms a complex pattern consisting of out-of-plane domains while the in-plane magnetization shows a maze pattern. 相似文献
44.
晶体硅薄膜电池制备技术及研究现状 总被引:2,自引:0,他引:2
晶体硅薄膜太阳电池近些年来得到广泛的研究和初步的商业化探索。根据所采用的晶体硅薄膜沉积工艺中温度范围的不同,晶体硅薄膜电池研究可分为高温路线和低温路线两个不同发展方向。本文分别从这两个方向综述了目前国外晶体硅薄膜电池制备技术的最新进展,最新实验室研究结果。报导了晶体硅薄膜电池商业化进展状况,指出了晶体硅薄膜电池实现产业化必须解决的问题。 相似文献
45.
46.
聚氨酯-聚丙烯酸酯共聚乳液的成膜和性能 总被引:4,自引:0,他引:4
通过XPS和接触角测试研究了聚氨酯-聚丙烯酸酯共聚乳液在不同基材上的成膜情况,并对共聚胶膜的耐水性和附着力进行了考察.由于该共聚乳液同时存在着亲水组分和疏水组分,所以它在不同的基材上成膜可导致其膜表面的组成成分不同,因而导致其耐水性和附着力也随基材而异。结果表明,亲水性的聚氨酯组分均富集于胶膜内部,但胶膜底层聚氨酯组分的含量却随基材的不同而不同。在憎水且表面张力较高的基材上,共聚胶膜的耐水性良好;共聚胶膜的附着力在表面张力较高的基材上也良好。 相似文献
47.
H. Konishi 《Electrochimica acta》2003,48(5):563-568
Electrochemical implantation was performed at Ni electrodes to form DyNi2 films at 0.55 V (vs. Li+/Li), 0.62 V, and 0.70 V for 0.5-5.0 h in a molten LiCl-KCl-DyCl3 (0.50 mol%) system at 700 K. It was found that the DyNi2 films grew linearly with time with coulomb efficiency of about 100%. The obtained growth rates were higher at more negative potentials, i.e., 0.47 μm min−1 at 0.55 V, 0.32 μm min−1 at 0.62 V, and 0.14 μm min−1 at 0.70 V. On the analogy of the metal oxide growth, the observed rapid and linear growth of DyNi2 films may be explained by the existence of the outer and inner DyNi2 layers. 相似文献
48.
49.
Kenji Nomura Hiromichi OhtaKazushige Ueda Toshio Kamiya Masahiro HiranoHideo Hosono 《Thin solid films》2003,445(2):322-326
We have investigated the characteristics of transparent metal-insulator-semiconductor field-effect transistors (MISFETs) fabricated using InGaO3(ZnO)m (m=integer) single-crystalline thin films as n-channel layers and amorphous alumina as gate insulator films. The MISFETs exhibit good characteristics such as insensitivity to visible light illumination, off-current as low as ∼1 nA with a positive threshold voltage of ∼3 V and on/off current ratio of 105. The field-effect mobility increased from ∼1 to ∼10 cm2 (V s)−1 as the m-value increased. Room temperature Hall mobility also increased. However, unexpectedly these values were lower than the field-effect mobility. It is explained by existence of shallow localized state in the homologous compounds. 相似文献
50.