全文获取类型
收费全文 | 454篇 |
免费 | 6篇 |
专业分类
化学 | 299篇 |
晶体学 | 8篇 |
力学 | 3篇 |
数学 | 7篇 |
物理学 | 143篇 |
出版年
2022年 | 6篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 9篇 |
2011年 | 18篇 |
2010年 | 17篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 29篇 |
2005年 | 20篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 14篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 11篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1968年 | 4篇 |
1967年 | 3篇 |
排序方式: 共有460条查询结果,搜索用时 0 毫秒
361.
Prof. Dr. Yasutomo Segawa Akiko Yagi Katsuma Matsui Prof. Dr. Kenichiro Itami 《Angewandte Chemie (International ed. in English)》2016,55(17):5136-5158
The selective and predictable synthesis of structurally uniform carbon nanotubes (CNTs) represents a long‐standing goal in both nanocarbon science and synthetic organic chemistry. This Review focuses on synthetic studies toward the controlled synthesis of CNTs with single chirality through the organic synthesis of CNT segments and the organic template assisted growth of CNTs. 相似文献
362.
363.
Kakiya H Yagi K Shinokubo H Oshima K 《Journal of the American Chemical Society》2002,124(31):9032-9033
A convergent synthesis of a pyrimidine core has been achieved. Treatment of alpha,alpha-dibromo oxime ethers, which are easily derived from the corresponding esters, with a variety of Grignard reagents provides trisubstituted pyrimidines in good yields. This new method offers an easy access to functionalized pyrimidines. 相似文献
364.
Mil'nikov GV Yagi K Taketsugu T Nakamura H Hirao K 《The Journal of chemical physics》2004,120(11):5036-5045
A practical and accurate semiclassical method for calculating the tunneling splitting of the ground state in polyatomic molecules is presented based on a recent version of the instanton theory [J. Chem. Phys. 115, 6881 (2001)]. The method uses ab initio quantum chemical data for the potential energy surface without any concomitant extrapolation and requires only a small number of ab initio data points to get convergence even for large molecules. This enables one to use an advanced level of electronic structure theory and achieve a high accuracy of the result. The method is applied to the 9-atomic malonaldehyde molecule by making use of the potential energy surface at the level of CCSD(T) with the hybrid basis set of aug-cc-pVTZ (for oxygen atoms and the transferred hydrogen atom) and cc-pVTZ (for other atoms). 相似文献
365.
Yagi I Mikami K Ebina K Okamura M Uosaki K 《The journal of physical chemistry. B》2006,110(29):14192-14197
Ultrafast photoexcited carrier dynamics in CdS nanoparticles prepared by an AOT/n-heptane reversed micelle system were investigated by a femtosecond visible-pump/mid-IR probe technique. A mid-IR probe beam was found to mainly probe the ultrafast dynamics of photoexcited electrons in the conduction band. Dispersions of CdS nanoparticles with 8 different mean diameters from 2.9 to 4.1 nm were prepared by tuning the mole ratio between water and AOT (W = [H(2)O]/[AOT]) in the reversed micelle systems. The excited state lifetime strongly depended on the mean size of CdS nanoparticles with a maximum around a mean diameter of 3.5 nm. This result was explained by considering the balance between the carrier recombination rates via surface states and those via interior states. The relationship between the excited state lifetime and the size of CdS nanoparticles was drastically changed when the surface was terminated by thiol molecules. 相似文献
366.
Taguchi M Yagi I Nakagawa M Iyoda T Einaga Y 《Journal of the American Chemical Society》2006,128(33):10978-10982
The first photocontrollable magnetic nanoparticles containing CdS and Prussian blue (PB) have been created using reverse micelles as nanoreactors. Photoinduced electron transfer from CdS to PB in the reverse micelle changed the magnetic properties of the composite nanoparticles from ferromagnetic to paramagnetic. The magnetization in the ferromagnetic region below 4 K was substantially decreased after UV light illumination and could be restored almost to its original level by thermal treatment at room temperature. This novel strategy of designing composite nanoparticles containing photoconductive semiconductors and magnetic materials to create photoswitchable magnetic materials may open many possibilities in the development of magneto-optical devices. 相似文献
367.
Pinky A. Bautista Tokiya Abe Masahiro Yamaguchi Yukako Yagi Nagaaki Ohyama 《Optical Review》2005,12(1):7-14
Histological structures of a pathological tissue sample convey information relevant to the diagnosis of the disease that might have afficted the person. To reveal the morphology of these structures clearly, pathological tissues are stained. In this paper, a digital staining methodology for pathological tissue samples is introduced. Digital staining implies the application of digital processing techniques to transform the image of an unstained sample to its stained image counterpart. In the method, the transmittance spectra of the unstained and Hematoxylin and Eosin (H&E) stained multispectral images (16 bands) of specific tissue components are utilized. Two experiments were conducted to probe the possibility of the digital staining framework: the linear mapping of spectral transmittances, and the classification of spectral transmittances in conjunction with the linear mapping of specific transmittance data sets. The method classified the four tissue components, e.g. nucleus, cytoplasm, red blood cells, and the white region (region devoid of tissue structures), while the misclassifications between components with spectral transmittances that are closely similar were not completely rectified. © 2005 The Optical Society of Japan 相似文献
368.
Jong-Ho Park Jung-Hwan Kim Sung-Ho Suh Jang-Kyoo Shin Minho Lee Pyung Choi Tetsuya Yagi 《Optical Review》2005,12(1):15-19
We have designed and fabricated a complementary metal-oxide-semiconductor (CMOS) vision chip by modeling cells of the human retina as hardware that are involved in edge and motion detection. There are several fluctuation factors which affect the characteristics of metal-oxide-semiconductor field effect transistors (MOSFETs) through the CMOS fabrication process and this effect appears as the output offset of the vision chip, which is composed of pixel arrays and readout circuits. The vision chip which detects edge and motion information from an input image is used for the input stage of other systems. Therefore, the output offset of the vision chip determines the efficiency of the entire system. In order to eliminate the offset at the output stage, we designed a vision chip utilizing the correlated double sampling (CDS) technique. The chip has been fabricated using a 0.6 m standard CMOS process. With reliable output characteristics, this chip can be used at the input stage for various applications. © 2005 The Optical Society of Japan 相似文献
369.
Kaori Yagi 《Tetrahedron》2006,62(20):4933-4940
CuCN-catalyzed reaction of the (1R)-isomer of 4-cyclopentene-1,3-diol monoacetate with TBDPSO(CH2)6MgCl produced an SN2-type product regioselectively in high yield. Mitsunobu inversion of the product and subsequent Claisen rearrangement furnished aldehyde with the two side chains, from which the title compounds were synthesized efficiently. 相似文献
370.
A tungsten trioxide (WO3) film was prepared by calcination from a precursor paste including suspended ammonium tungstate and polyethylene glycol (PEG). The ammonium tungstate suspension was yielded by an acid-base reaction of tungstic acid and an ammonium solution followed by deposition with ethanol addition. Thermogravimetric (TG) analysis showed that the TG profile of PEG is significantly influenced by deposited ammonium tungstate, suggesting that PEG is interacting strongly with deposited ammonium tungstate in the suspension paste. X-ray diffraction (XRD) data indicated that the WO3 film is crystallized by sintering over 400 °C. The scanning electron microscopic (SEM) measurement showed that the film is composed of the nano-structured WO3 platelets. The semiconductor properties of the film were examined by Mott-Schottky analysis to give flat band potential EFB=0.30 V vs. saturated calomel reference electrode (SCE) and donor carrier density ND=2.5×1022 cm−3, latter of which is higher than previous WO3 films by two orders of magnitude. The higher ND was explained by the large interfacial heterojunction area caused by the nano-platelet structure, which apparently increases capacitance per a unit electrode area. The WO3 film sintered at 550 °C produced 3.7 mA cm−2 of a photoanodic current at 1.2 V vs. SCE under illumination with a 500 W xenon lamp due to catalytic water oxidation. This photocurrent was 4.5-12.8 times higher than those for the other control WO3 films prepared by similar but different procedures. The high catalytic activity could be explained by the nano-platelet structure. The photocurrent was generated on illumination of UV and visible light below 470 nm, and the maximum incident photon-to-current conversion efficiency (IPCE) was 47% at 320 nm at 1.2 V. Technically important procedures for preparation of nano-structured platelets were discussed. 相似文献