全文获取类型
收费全文 | 113篇 |
免费 | 3篇 |
专业分类
化学 | 99篇 |
力学 | 1篇 |
数学 | 1篇 |
物理学 | 15篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 9篇 |
2007年 | 2篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 5篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有116条查询结果,搜索用时 234 毫秒
61.
Koyama T Miyata Y Asaka K Shinohara H Saito Y Nakamura A 《Physical chemistry chemical physics : PCCP》2012,14(3):1070-1084
Excitation energy transfer has long been an intriguing subject in the fields of photoscience and materials science. Along with the recent progress of photovoltaics, photocatalysis, and photosensors using nanoscale materials, excitation energy transfer between a donor and an acceptor at a short distance (≤1-10 nm) is of growing importance in both fundamental research and technological applications. This Perspective highlights our recent studies on exciton energy transfer between carbon nanotubes with interwall (surface-to-surface) distances of less than ~1 nm, which are equivalent to or shorter than the size of one-dimensional excitons in carbon nanotubes. We show exciton energy transfer in bundles of single-walled carbon nanotubes with the interwall distances of ~0.34 and 0.9 nm (center-to-center distances ~1.3-1.4 and 1.9 nm). For the interwall distance of ~0.34 nm (center-to-center distance ~1.3-1.4 nm), the transfer rate per tube from a semiconducting tube to adjacent semiconducting tubes is (1.8-1.9) × 10(12) s(-1), and that to adjacent metallic tubes is 1.1 × 10(12) s(-1). For the interwall distance of ~0.9 nm (center-to-center distance ~1.9 nm), the transfer rate per tube from a semiconducting tube to adjacent semiconducting tubes is 2.7 × 10(11) s(-1). These transfer rates are much lower than those predicted by the F?rster model calculation based on a point dipole approximation, indicating the failure of the conventional F?rster model calculations. In double-walled carbon nanotubes, which are equivalent to ideal nanoscale coaxial cylinders, we show exciton energy transfer from the inner to the outer tubes. The transfer rate between the inner and the outer tubes with an interwall distance of ~0.38 nm is 6.6 × 10(12) s(-1). Our findings provide an insight into the energy transfer mechanisms of one-dimensional excitons. 相似文献
62.
Yasumitsu Matsuo Yuya Shimizu Tomoaki Suzuki Seiichiro Ikehata 《Solid State Communications》2004,129(8):529-532
Measurements of the spin-lattice relaxation time, NMR absorption line and magnetization have been carried out on the Tl3H(SO4)2 crystal below 50 K. The anomaly at around 7 K was: (1) the spin-lattice relaxation times of 1H and 205Tl nuclei increase steeply with decreasing temperature below 7 K, (2) the NMR absorption lines below 7 K shift to the high-magnetic field side in comparison with that above 7 K, and (3) the 1H NMR line width exhibits a drastic increase of the line width with decreasing temperature below 7 K. These results indicate that the magnetic dipole fluctuation of the proton changes at 7 K. On the other hand, there are no remarkable anomalies of magnetic susceptibility at around 7 K. From these results it is deduced that the anomaly at around 7 K is caused by the change in quantum mechanical process of the proton from proton tunneling to zero-point vibration of hydrogen in the hydrogen bond with the decrease of temperature. 相似文献
63.
Dr. Yasufumi Takahashi Dr. Yu Kobayashi Dr. Ziqian Wang Dr. Yoshikazu Ito Masato Ota Dr. Hiroki Ida Dr. Akichika Kumatani Dr. Keisuke Miyazawa Prof. Takeshi Fujita Prof. Hitoshi Shiku Yuri E. Korchev Dr. Yasumitsu Miyata Prof. Takeshi Fukuma Prof. Mingwei Chen Prof. Tomokazu Matsue 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3629-3636
High-resolution scanning electrochemical cell microscopy (SECCM) is used to image and quantitatively analyze the hydrogen evolution reaction (HER) catalytically active sites of 1H-MoS2 nanosheets, MoS2, and WS2 heteronanosheets. Using a 20 nm radius nanopipette and hopping mode scanning, the resolution of SECCM was beyond the optical microscopy limit and visualized a small triangular MoS2 nanosheet with a side length of ca. 130 nm. The electrochemical cell provides local cyclic voltammograms with a nanoscale spatial resolution for visualizing HER active sites as electrochemical images. The HER activity difference of edge, terrace, and heterojunction of MoS2 and WS2 were revealed. The SECCM imaging directly visualized the relationship of HER activity and number of MoS2 nanosheet layers and unveiled the heterogeneous aging state of MoS2 nanosheets. SECCM can be used for improving local HER activities by producing sulfur vacancies using electrochemical reaction at the selected region. 相似文献
64.
Fused cyclobutanone derivatives have been utilized as intermediates in a variety of synthetic schemes.1) We are investigating the synthesis and ring opening reactions of cyclobutanones fused to indoles, benzo[b]furans, and benzo[b]-thiophenes, in part with the hope of discovering a novel method for introduction of two carbon atoms to such heteroaromatic systems. In this communication the synthesis and Beckmann fission2) of the cyclobutanone derivatives fused to 1-benzoyl-indoles and benzo[b]thiophene are described. This provides a new entry into indole-2-acetonitriles3) and benzo[b]thiophene-2-acetonitrile.4) 相似文献
65.
Kentaro Takahama Asami Takada Shota Tada Mai Shimizu Kazutoshi Sayama Riki Kurokawa Takanori Oyoshi 《Chemistry & biology》2013,20(3):341-350
- Download : Download high-res image (172KB)
- Download : Download full-size image
66.
Kyakuno H Matsuda K Yahiro H Inami Y Fukuoka T Miyata Y Yanagi K Maniwa Y Kataura H Saito T Yumura M Iijima S 《The Journal of chemical physics》2011,134(24):244501
Studies on confined water are important not only from the viewpoint of scientific interest but also for the development of new nanoscale devices. In this work, we aimed to clarify the properties of confined water in the cylindrical pores of single-walled carbon nanotubes (SWCNTs) that had diameters in the range of 1.46 to 2.40 nm. A combination of x-ray diffraction (XRD), nuclear magnetic resonance, and electrical resistance measurements revealed that water inside SWCNTs with diameters between 1.68 and 2.40 nm undergoes a wet-dry type transition with the lowering of temperature; below the transition temperature T(wd), water was ejected from the SWCNTs. T(wd) increased with increasing SWCNT diameter D. For the SWCNTs with D = 1.68, 2.00, 2.18, and 2.40 nm, T(wd) obtained by the XRD measurements were 218, 225, 236, and 237 K, respectively. We performed a systematic study on finite length SWCNT systems using classical molecular dynamics calculations to clarify the effect of open ends of the SWCNTs and water content on the water structure. It was found that ice structures that were formed at low temperatures were strongly affected by the bore diameter, a = D - σ(OC), where σ(OC) is gap distance between the SWCNT and oxygen atom in water, and the number of water molecules in the system. In small pores (a < 1.02 nm), tubule ices or the so-called ice nanotubes (ice NTs) were formed irrespective of the water content. On the other hand, in larger pores (a > 1.10 nm) with small water content, filled water clusters were formed leaving some empty space in the SWCNT pore, which grew to fill the pore with increasing water content. For pores with sizes in between these two regimes (1.02 < a < 1.10 nm), tubule ice also appeared with small water content and grew with increasing water content. However, once the tubule ice filled the entire SWCNT pore, further increase in the water content resulted in encapsulation of the additional water molecules inside the tubule ice. Corresponding XRD measurements on SWCNTs with a mean diameter of 1.46 nm strongly suggested the presence of such a filled structure. 相似文献
67.
68.
Hidetaro Yasumitsu Yasuhiro Ozeki Sarkar M. A. Kawsar Yuki Fujii Masayuki Sakagami Yuhsi Matuo Tosifusa Toda Hiroshi Katsuno 《Electrophoresis》2010,31(12):1913-1917
SDS‐PAGE and CBB staining are two of the most popular methods used for protein analysis. Although many reports that describe such staining methods have been published, these conventional protocols require several hours or days for staining and de‐staining. In this study we describe a recently developed, fast and sensitive CBB staining method that utilizes the staining solution of RAMA that consists of the low‐cost reagents: CBB R250, acetic acid, methanol and ammonium sulfate, and the destaining solution of water. Our method dose dependently detects 12 nanograms protein within 60 min and with a wide protein spectrum. Although the features of the dose‐dependent relationship depend upon protein amounts and protein types, for most of the protein samples tested, a linear relationship was observed in the region from 12 to 330 ng. Moreover, through further washing, the detection sensitivity of protein is enhanced and reaches a maximum at 1.4 ng and then gradually decreases in the de‐staining process. It has been shown recently through MS analyses that the sensitive colloidal CBB staining methods frequently result in artifactual methylations due to the strong acid and long contact during staining and the destaining processes. Such artifacts were reported to be reduced by the replacement of strong inorganic acid with acetic acid and because RAMA utilizes acetic acid and is in contact with the proteins for a short time during staining and de‐staining, it is expected that in vitro artifacts will be reduced. Finally, MS analyses of RAMA‐stained protein bands were revealed not to have been methylated. 相似文献
69.
70.