全文获取类型
收费全文 | 5132篇 |
免费 | 414篇 |
国内免费 | 265篇 |
专业分类
电工技术 | 56篇 |
综合类 | 152篇 |
化学工业 | 1510篇 |
金属工艺 | 319篇 |
机械仪表 | 226篇 |
建筑科学 | 18篇 |
矿业工程 | 33篇 |
能源动力 | 149篇 |
轻工业 | 385篇 |
水利工程 | 5篇 |
石油天然气 | 68篇 |
武器工业 | 8篇 |
无线电 | 1182篇 |
一般工业技术 | 1489篇 |
冶金工业 | 75篇 |
原子能技术 | 83篇 |
自动化技术 | 53篇 |
出版年
2024年 | 21篇 |
2023年 | 146篇 |
2022年 | 147篇 |
2021年 | 181篇 |
2020年 | 187篇 |
2019年 | 191篇 |
2018年 | 180篇 |
2017年 | 211篇 |
2016年 | 212篇 |
2015年 | 171篇 |
2014年 | 268篇 |
2013年 | 326篇 |
2012年 | 288篇 |
2011年 | 443篇 |
2010年 | 263篇 |
2009年 | 326篇 |
2008年 | 254篇 |
2007年 | 255篇 |
2006年 | 277篇 |
2005年 | 212篇 |
2004年 | 210篇 |
2003年 | 183篇 |
2002年 | 160篇 |
2001年 | 127篇 |
2000年 | 83篇 |
1999年 | 61篇 |
1998年 | 58篇 |
1997年 | 40篇 |
1996年 | 48篇 |
1995年 | 50篇 |
1994年 | 47篇 |
1993年 | 36篇 |
1992年 | 33篇 |
1991年 | 26篇 |
1990年 | 28篇 |
1989年 | 20篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有5811条查询结果,搜索用时 31 毫秒
101.
为了提供磷酸奥司他韦药品拉曼检测参考需求,对磷酸奥司他韦的拉曼散射光谱进行了实验测量和理论分析。检测了磷酸奥司他韦标准化学对照品200~4000cm-1的自然拉曼光谱,通过构建磷酸奥司他韦分子空间结构,利用密度泛函(m06-2x/6-31++g**)方法优化结构计算获得的理论拉曼光谱。分析指认了200~3800cm-1区间特征频率的振动谱,为拉曼光谱技术在药品鉴定领域提供参考与应用。 相似文献
102.
2—巯基苯并噻唑在铜表面的吸附状态 总被引:4,自引:0,他引:4
在pH值大于6时,2-巯基苯并噻唑(MBT)在银和铜表面具有相同的吸附状态;随溶液pH值降低,部分吸附的硫醇离子逐渐异构化为硫酮,破坏了MBT平面吸附层。在pH值高于3时,MBT在铜表面仍然以其分子平面平行于表面,起到阻挡侵蚀分子的作用,由此可知在弱碱性溶液中它对于铜有更的保护效果。 相似文献
103.
104.
105.
Robert B. Heimann 《Surface & coatings technology》2006,201(5):2012-2019
Osteoconductive hydroxyapatite coatings for metallic endoprostheses for hip and knee joint replacement provide a state-of-the-art template for enhanced in-growth of bone cells. However, the high temperature of the plasma jet leads to large scale dehydroxylation and decomposition of the starting powder. A model is being developed to explain the formation of chemically and mechanically inhomogeneous porous calcium phosphate coatings deposited by atmospheric plasma spraying onto titanium alloy substrates. In addition the biofunctionality is being discussed of titania bond coats and their influence on the in vivo performance of hydroxyapatite-titania duplex coating systems. 相似文献
106.
Glass transition temperatures Tg and Raman spectra of KPO3·Ln(PO3)3 (Ln=rare earth ion) glasses were measured for all rare earth members (except Pm). From the series behavior of the Tg and Raman data, it is concluded that the coordination number around rare earth ions changes, probably from nine to eight, in the middle of the rare earth series. 相似文献
107.
Diamond deposition on a series of ferrous alloy substrates has been examined in a microwave plasma enhanced chemical vapor deposition reactor. The results show that the nucleation, growth, and adhesion properties of the diamond are strongly dependent on the types and relative concentrations of the alloy elements in the substrates. Along with high nucleation densities, continuous and adherent diamond films have been successfully fabricated on the Al-modified alloy substrates, even in the absence of inter-layers or nucleation enhancing surface pre-treatment. The mechanism is preliminarily clarified regarding the delicate competition and balance between the base metal and the alloying elements in terms of their activation and deactivation ability on catalyzing graphite formation during deposition process. 相似文献
108.
Density functional theory (DFT) studies on adsorption of several gaseous homo- and hetero-diatomic molecules (AB) including H2, O2, N2, NO and CO on external surface of H-capped pristine armchair (5, 5) single-walled carbon nanotube (SWCNT) were conducted. Structures of C70H10 and the corresponding C70H10–AB adducts were fully optimized at the B3LYP/6-311G* level of theory. Calculated HOMO/LUMO energy gaps (Eg), 13C NMR chemical shifts and IR/Raman parameters were analyzed and critically compared with available experimental data. Significant changes of carbon NMR atom chemical shifts (up to −100 ppm) and shielding anisotropies (up to −180 ppm) at sites of addition were observed. Functionalized SWCNTs produced IR and Raman spectra different from the pristine nanotube model. The selective changes in vibrational spectra will help in assigning the topology of functionalization at the nanotube wall. 相似文献
109.
110.
In this paper, we review the state-of-the-art in surface-enhanced Raman scattering (SERS) based optical detection techniques
with an application focus on cancer diagnostics. As we describe herein, SERS has several analytical, biological and engineering
advantages over other methods including extremely high sensitivity, inherent molecular specificity of unlabeled targets, and
narrow spectral bands. We review advances in both in vitro and in vivo applications of SERS and examine how technical issues
with the technology are being addressed. A special technology focus is given to emerging optofluidic devices which aim to
merge microfluidic and optical detection technologies into simple packages. We conclude with a brief discussion of some of
the emerging challenges in the field and some of the approaches that are likely to enhance their application.
Y. S. Huh and A. J. Chung contributed equally. 相似文献