全文获取类型
收费全文 | 933篇 |
免费 | 36篇 |
国内免费 | 3篇 |
专业分类
化学 | 672篇 |
晶体学 | 8篇 |
力学 | 13篇 |
数学 | 78篇 |
物理学 | 201篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 3篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 25篇 |
2015年 | 20篇 |
2014年 | 29篇 |
2013年 | 52篇 |
2012年 | 60篇 |
2011年 | 73篇 |
2010年 | 38篇 |
2009年 | 45篇 |
2008年 | 80篇 |
2007年 | 77篇 |
2006年 | 43篇 |
2005年 | 43篇 |
2004年 | 50篇 |
2003年 | 56篇 |
2002年 | 50篇 |
2001年 | 8篇 |
2000年 | 15篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 14篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1974年 | 4篇 |
1973年 | 7篇 |
1969年 | 3篇 |
排序方式: 共有972条查询结果,搜索用时 15 毫秒
1.
2.
Naoto Sato Taiki Hayashi Kazuma Tochigi Prof. Hiroaki Wada Prof. Atsushi Shimojima Prof. Kazuyuki Kuroda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(33):7860-7865
Eight corners of a double-four ring cage-type germanoxane, containing a fluoride ion, were successfully silylated by the combination of chlorosilanes and silazanes. Three different silyl groups, trimethylsilyl, dimethylsilyl, and dimethylvinylsilyl, were attached on the corners of germanoxane cage. The solubility and reactivity of the cage modified with dimethylvinylsilyl groups were significantly increased, allowing for further reaction. Hydrosilylation reaction between dimethylvinylsilylated cage geramanoxanes and dimethylsilylated cage siloxanes afforded porous solids. Functionalization of the corners of germanoxanes with silyl groups should provide valuable building blocks in various functional materials. 相似文献
3.
4.
Sait Sadiq M. Ahmed Syed Faraz Rafiq Muhammad Rahil 《Journal of Thermal Analysis and Calorimetry》2021,143(3):1935-1942
Journal of Thermal Analysis and Calorimetry - The purpose of this study is to measure and document the maximum level of broadband radiofrequency electromagnetic radiations in the vicinity of... 相似文献
5.
Seong-Wook Kim Hyeonjung Jung Dr. Mahmut Sait Okyay Dr. Hyuk-Jun Noh Sein Chung Young Hyun Kim Jong-Pil Jeon Prof. Dr. Bryan M. Wong Prof. Dr. Kilwon Cho Dr. Jeong-Min Seo Prof. Dr. Jung-Woo Yoo Prof. Dr. Jong-Beom Baek 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310560
The development of covalent organic frameworks (COFs) with efficient charge transport is of immense interest for applications in optoelectronic devices. To enhance COF charge transport properties, electroactive building blocks and dopants can be used to induce extended conduction channels. However, understanding their intricate interplay remains challenging. We designed and synthesized a tailor-made COF structure with electroactive hexaazatriphenylene (HAT) core units and planar dioxin (D) linkages, denoted as HD-COF. With the support of theoretical calculations, we found that the HAT units in the HD-COF induce strong, eclipsed π–π stacking. The unique stacking of HAT units and the weak in-plane conjugation of dioxin linkages leads to efficient anisotropic charge transport. We fabricated HD-COF films to minimize the grain boundary effect of bulk COFs, which resulted in enhanced conductivity. As a result, the HD-COF films showed an electrical conductivity as high as 1.25 S cm−1 after doping with tris(4-bromophenyl)ammoniumyl hexachloroantimonate. 相似文献
6.
The Critical Effect of Niobium Doping on the Formation of Mesostructured TiO2: Single‐Crystalline Ordered Mesoporous Nb‐TiO2 and Plate‐like Nb‐TiO2 with Ordered Mesoscale Dimples 下载免费PDF全文
Takamichi Matsuno Dr. Yoshiyuki Kuroda Prof.Dr. Atsushi Shimojima Prof.Dr. Hiroaki Wada Prof.Dr. Kazuyuki Kuroda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(37):13073-13079
Highly ordered mesoporous niobium‐doped TiO2 with a single‐crystalline framework was prepared by using silica colloidal crystals with ca. 30 nm in diameter as templates. The preparation of colloidal crystals composed of uniform silica nanoparticles is a key to obtain highly ordered mesoporous Nb‐doped TiO2. The XPS measurements of Nb‐doped TiO2 showed the presence of Nb5+ and correspondingly Ti3+. With the increase in the amount of doped Nb, the crystalline phase of the product was converted from rutile into anatase, and the lattice spacings of both rutile and anatase phases increased. Surprisingly, the increase in the amount of Nb led to the formation of plate‐like TiO2 with dimpled surfaces on one side, which was directly replicated from the surfaces of the colloidal silica crystals. 相似文献
7.
8.
Activated carbon production from almond shells using phosphoric acid activation agent was achieved by applying both conventional heating and microwave heating in succession. The morphology and surface properties of activated carbon were studied using thermogravimetric and differential gravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller analysis. A surface area of 1128 m2/g was achieved by optimizing the microwave power (500?W), microwave application time (15?minutes), conventional heating time (45?minutes), conventional heating temperature (500?°C), and the phosphoric acid:sample ratio (0.7:1). An adsorption capacity of methylene blue of 148?mg/g and an iodine value of 791?mg/g was obtained for the prepared activated carbon. 相似文献
9.
Mengfei Wang Dr. Kei Murata Prof. Kazuyuki Ishii 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(35):8994-9002
Mono- and di-nuclear tricarbonyl Re(I) tetraazaporphyrin complexes ( Re1TAP and Re2TAP ) are investigated and compared with Re(I) phthalocyanine complexes ( Re1Pc and Re2Pc ). Although Re2Pc is unstable in polar solvents, and easily undergoes demetallation reaction, the coordination of the TAP ligand significantly improves the tolerance toward polar solvents, affording more stability to Re2TAP . Additionally, the incorporation of [Re(CO)3]+ unit(s) and the TAP ligand results in remarkable positive shifts in both oxidation and reduction potentials. Consequently, the more positive oxidation potentials of the ReTAP complexes significantly increase the tolerance toward oxidation, while the reduction potential indicates that Re2TAP is suitable for a soluble electron acceptor. In contrast to Re1Pc and Re2Pc , Re1TAP and Re2TAP show unique broad Q bands, which can be attributed to the admixture of the π-π* and metal-to-ligand charge transfer characters, owing to the lowered π orbital energy in the TAP complexes. This study is useful for controlling electronic properties and realizing high stability in Pc analogues. 相似文献
10.