全文获取类型
收费全文 | 365篇 |
免费 | 18篇 |
专业分类
化学 | 295篇 |
晶体学 | 11篇 |
力学 | 2篇 |
数学 | 19篇 |
物理学 | 56篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 14篇 |
2013年 | 20篇 |
2012年 | 34篇 |
2011年 | 27篇 |
2010年 | 16篇 |
2009年 | 19篇 |
2008年 | 34篇 |
2007年 | 24篇 |
2006年 | 20篇 |
2005年 | 18篇 |
2004年 | 19篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 7篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有383条查询结果,搜索用时 15 毫秒
151.
Inside Cover: Supramolecular Engineering of Oligothiophene Nanorods without Insulators: Hierarchical Association of Rosettes and Photovoltaic Properties (Chem. Eur. J. 49/2014)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Prof. Dr. Shiki Yagai Mika Suzuki Dr. Xu Lin Marina Gushiken Takuya Noguchi Prof. Dr. Takashi Karatsu Prof. Dr. Akihide Kitamura Prof. Dr. Akinori Saeki Prof. Dr. Shu Seki Dr. Yoshihiro Kikkawa Yuki Tani Prof. Dr. Ken‐ichi Nakayama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16010-16010
152.
153.
Kanji Takahashi Michihiro Kawabata Daisuke Uemura Shuichi Iwadare Ryuji Mitomo Fumio Nakano Akinori Matsuzaki 《Tetrahedron letters》1985,26(8):1077-1078
Based on the spectroscopic analysis and correlation with the degradation products of oxazolomycin, the structure of neooxazolomycin has been elucidated. 相似文献
154.
Perchlorate-selective electrodes prepared from a new matrix, Urushi, and tri-n-octylmethylammonium perchlorate or the Corning perchlorate liquid ion-exchanger are described. The electrodes have linear response ranges and selectivity similar to those of commercial perchlorate-selective electrodes. The membranes are hard, lustrous and smooth; their useful lifetimes exceed 1000 h. 相似文献
155.
6,11-Dihydrobenzo[b]pyrrolo[4,3,2-de][1,10]phenanthroline-5,8-dione (6), which possesses a unique heterocyclic ring system similar to that in plakinidines A-D (1-4), was synthesized from 2-acetyl-3′-nitrodiphenylamine (16) in nine steps. 相似文献
156.
Radiationless transitions of molecules accompanied by a large nuclear rearrangement were investigated. A general formula which includes interference effects among promoting modes was used. Numerical analysis for the model system revealed that the energy-gap dependence of the transition probability exhibits quite different behavior from the usual gaussian-type dependence. 相似文献
157.
Akinori Takasu Shigeki Ohmori Yutaka Yamauchi Tadamichi Hirabayashi 《Journal of polymer science. Part A, Polymer chemistry》2002,40(24):4477-4484
Amphiphilic and heterotactic‐rich poly(vinyl alcohol) (PVA) macromonomer, that is, PVA having a phenyl or phenoxyethyl methacrylate unit as the polymerizable end group, was synthesized via the aldol‐type group‐transfer polymerization (aldol‐GTP) technique. Aldol‐GTPs of vinyloxytriethylsilane (VOTES) were carried out in dichloromethane with 4‐methacryloylbenzaldehyde and 4‐(2‐methacryloylethoxy)benzaldehyde as the initiators with various Lewis acids. The polymerizations proceeded smoothly to give silylated PVA macromonomers (number‐average molecular weights: 1.3 × 103–1.96 × 104). Poly(VOTES) was easily desilylated to give heterotactic‐rich PVA macromonomer in good yield. The critical micelle concentration of the PVA macromonomer was determined by surface‐tension measurement. Micellar polymerization of the amphiphilic macromonomer gave comb‐shaped (graft) polymer having PVA side chains effectively (conversion: 80–82%), whereas polymerization in dimethyl sulfoxide (homogeneous state) did not. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4477–4484, 2002 相似文献
158.
Highly efficient Peterson olefination leading to unsaturated selenoamides and their characterization
The Peterson olefination of aromatic aldehydes with an alpha-silyl selenoacetamide proceeded smoothly with high stereoselectivity to give E-alpha,beta-unsaturated selenoamides in good to high yields. The reaction with aldehydes bearing alkenyl and dienyl groups gave the corresponding selenoamides bearing dienyl and trienyl groups, but the stability of the products depended on the substituents on the aromatic ring. X-ray molecular analysis disclosed that the alpha,beta,gamma,delta-unsaturated selenoamides had a nearly planar structure. In the (77)Se NMR spectra, signals were observed in the region greater than 130 ppm depending on the substituents on the aromatic ring, whereas the (1)J coupling constant between the carbon atom and the selenium atom was almost independent of the substituents. A linear relationship was observed between the chemical shifts in the (77)Se NMR spectra and Hammet sigma parameters, and this correlation was retained even when one or two alkenyl groups were introduced to alpha,beta-unsaturated selenoamides, although it became less sensitive. 相似文献
159.
Abstract— Proton transfer was theoretically examined as a possible primary process of vision. The motion of protons in the adiabatic potential of the Schiff base hydrogen bond was investigated in terms of quantum mechanics. The probability of proton transfer from the Schiff base nitrogen (i.e. the unprotonation of Schiff base) was found to increase as the retinal rotated around 11–12. double bond by 90°. The results also suggested that the proton transfer can take place before or during the transition from the excited to ground state (excited state proton transfer). We proposed that such excited state proton transfer is one of the elementary processes in primary visual photochemistry, and this process leads to the unprotonated visual pigment, hyposorhodopsin, which has been experimentally verified as one of the primary photoproducts of rhodopsin. The probability of this process could be comparable to the conventional process leading to the protonated intermediate, bathorhodopsin. The relation of these results with the recent experimental data is discussed. 相似文献
160.
Franck Dumeignil Danhong Wang Eika W Qian Shinichi Inoue Akinori Muto Toshiaki Kabe Atsushi Ishihara 《Research on Chemical Intermediates》2005,31(9):819-832
The first part of this paper deals with the morphology of the MoS2 phase and its oxide precursor, the MoO3 phase, mainly from a geometrical point of view. After giving a brief review of the literature describing the structure of
these compounds, Mo densities in both phases were calculated along various crystallographic planes. Further, using structural
models recently proposed by others, Mo densities in MoS2 were also calculated in the case of an epitactic growth on γ-Al2O3 and TiO2 model surfaces. Then, the calculated Mo densities were compared with experimental results (Mo density when HDS activity is
maximal) previously obtained for catalysts constituted of MoS2 supported on a low SSA TiO2, a high SSA TiO2 and a conventional γ-alumina. It was suggested that either on alumina or titania the MoS2 phase is growing as (100) MoS2 planes. However, while on the alumina the optimal MoS2 phase might be constituted of dispersed MoS2 slabs covering only a part of the alumina surface (2.9–3.9 Mo atoms/nm2), on titania the optimal MoS2 phase might be constituted of a uniform MoS2 monolayer (5.2 atoms/nm2 for the high SSA titania, which is equal to the Mo density of a perfect MoS2 (100) plane). This difference may originate in the creation of a 'TiMoS' phase enhancing the S atoms mobility over Mo/TiO2-sulfided catalysts. Indeed, while in the case of a γ-alumina carrier the active sites (labile S atoms) are located on the edge of MoS2 slabs making the ratio Moedge/Mototal a crucial parameter for the catalytic performances, in the case of a titania carrier the labile sulfur atoms might be statistically
distributed all over the TiMoS active phase. Further, the higher Mo density observed over the high SSA titania (5.2 atoms/nm2) when compared to that over the low SSA titania (4.2 atoms/nm2) was supposedly due to the pH-swing method advantageously used to prepare the former carrier. Indeed, this method allows
giving a solid with enhanced mechanical properties providing a good stability to the derived catalysts under experimental
conditions. In addition, this TiO2 carrier exhibits a great homogeneity, with a surface structure substantially uniform, which might be adequate for a long-range
growth of (100) MoS2 slabs. 相似文献