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排序方式: 共有177条查询结果,搜索用时 15 毫秒
61.
Kinkini Bhattacharyya Tanusree Kar Rex A. Palmer Brian S. Potter Akira Inada 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):979-980
In the title compound, C30H50O3, the three six‐membered rings adopt chair, twist and twist‐boat conformations. The five‐membered ring is in a slightly distorted envelope conformation. The substituent on the five‐membered ring is in an extended conformation, with its two hydroxyl O atoms forming an intramolecular hydrogen bond. One of these O atoms also forms an intermolecular hydrogen bond with the oxygen of the carbonyl group in a neighbouring molecule. 相似文献
62.
Pornthep Chivavibul Manabu Enoki Shigeru Konda Yasushi Inada Tamotsu Tomizawa Akira Toda 《Journal of magnetism and magnetic materials》2011,323(3-4):306-310
An important issue in development of electrical steels for core-laminated products is to reduce core loss to improve energy conversion efficiency. This is usually obtained by tailoring the composition, microstructure, and texture of electrical steels themselves. A new technique to reduce core loss in electrical steel has been investigated. This technique involves electroless plating of magnetic thin coating onto the surface of electrical steel. The material system was electroless Ni–Co–P coatings with different thicknesses (1, 5, and 10 μm) deposited onto the surface of commercially available Fe–3% Si electrical steel. Characterization of deposited Ni–Co–P coating was carried out using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX) spectrometer. The deposited Ni–Co–P coatings were amorphous and composed of 56–59% Ni, 32–35% Co, and 8–10% P by mass. The effect of coatings on core loss of the electrical steel was determined using single sheet test. A core loss reduction of 4% maximum was achieved with the Ni–Co–P coating of 1 μm thickness at 400 Hz and 0.3 T. 相似文献
63.
Electrochemical characteristics of the transition metal dichalcogenide ZrSe2 were investigated as a cathode material. Lithium intercalated ZrSe2 showed a high reversibility of lithium ions in the non-aqueous solution. The discharge/ charge cycle was performed up to 160 times without deterioration. 相似文献
64.
We report (11)B and (195)Pt NMR measurements in noncentrosymmetric superconductor Li(2)Pt(3)B. We find that the spin susceptibility measured by the Knight shift remains unchanged across the superconducting transition temperature T(c). With decreasing temperature (T) below T(c), the spin-lattice relaxation rate 1/T(1) decreases with no coherence peak and is in proportion to T3. These results indicate that the Cooper pair is in the spin-triplet state and that there exist line nodes in the superconducting gap function. They are in sharp contrast to those in the isostructural Li(2)Pd(3)B which is a spin-singlet, s-wave superconductor, and are ascribed to the enhanced spin-orbit coupling due to the lack of spatial inversion symmetry. Our finding points to a new paradigm where exotic superconductivity arises in the absence of electron-electron correlations. 相似文献
65.
Kan’ichiro IshiuchiTakaaki Kubota Haruaki IshiyamaShigeki Hayashi Toshiro ShibataJun’ichi Kobayashi 《Tetrahedron letters》2011,52(2):289-292
New Lycopodium alkaloids, lyconadins C (1) and F (2), were isolated from the club moss Lycopodium complanatum. Lyconadin C (1) is a new C16N2-type Lycopodium alkaloid possessing unique fused-tetracyclic ring system consisting of a cycloheptene ring fused to a decahydroquinoline and pyridone rings. Lyconadin F (2) possesses a primary amide moiety in its molecular, which is the first example of Lycopodium alkaloids. Biogenetically, lyconadins C (1) and F (2) might be related to lyconadins A (4) and B (5). The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 2 was elucidated by chemical correlations with lyconadin B (5) through hemiaminal form of lyconadin F (3). 相似文献
66.
Many empirical parameters have been suggested to measure solvent effects in chemical reactions. Gutmann's donor number has been a successful parameter to quantify the electron-donating property of the solvent molecule; it is defined as the enthalpy change of the addition reaction of solvent molecule to SbCl(5) in 1,2-dichloroethane. Calorimetric measurements can be applied to determine the quantity. Because the existence of water is critical for reactions in organic solvents, we have analyzed the enthalpy change using the titration calorimetry while considering the complexation with water. The determined donor numbers of formamide, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and 1,1,3,3-tetramethylurea (TMU) are 22.4, 26.5, 30.0, and 40.4, respectively. The values of DMF and DMSO are in perfect agreement with those of Gutmann. A reliable value for TMU is obtained for the first time on the basis of the enthalpy change for the addition reaction. 相似文献
67.
Dr. Seiichi Uchiyama Kohki Kimura Chie Gota Dr. Kohki Okabe Kyoko Kawamoto Dr. Noriko Inada Dr. Toshitada Yoshihara Prof. Seiji Tobita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(31):9552-9563
An environment‐sensitive fluorophore can change its maximum emission wavelength (λem), fluorescence quantum yield (Φf), and fluorescence lifetime in response to the surrounding environment. We have developed two new intramolecular charge‐transfer‐type environment‐sensitive fluorophores, DBThD‐IA and DBSeD‐IA, in which the oxygen atom of a well‐established 2,1,3‐benzoxadiazole environment‐sensitive fluorophore, DBD‐IA, has been replaced by a sulfur and selenium atom, respectively. DBThD‐IA is highly fluorescent in n‐hexane (Φf=0.81, λem=537 nm) with excitation at 449 nm, but is almost nonfluorescent in water (Φf=0.037, λem=616 nm), similarly to DBD‐IA (Φf=0.91, λem=520 nm in n‐hexane; Φf=0.027, λem=616 nm in water). A similar variation in fluorescence properties was also observed for DBSeD‐IA (Φf=0.24, λem=591 nm in n‐hexane; Φf=0.0046, λem=672 nm in water). An intensive study of the solvent effects on the fluorescence properties of these fluorophores revealed that both the polarity of the environment and hydrogen bonding with solvent molecules accelerate the nonradiative relaxation of the excited fluorophores. Time‐resolved optoacoustic and phosphorescence measurements clarified that both intersystem crossing and internal conversion are involved in the nonradiative relaxation processes of DBThD‐IA and DBSeD‐IA. In addition, DBThD‐IA exhibits a 10‐fold higher photostability in aqueous solution than the original fluorophore DBD‐IA, which allowed us to create a new robust molecular nanogel thermometer for intracellular thermometry. 相似文献
68.
Christopher John Nuttall Yasuhira Inada Yoshihiro Watanabe Kiyoe Nagai Tsunehiro Muro Dam Hieu Chi 《Molecular Crystals and Liquid Crystals》2013,570(1):635-638
Abstract We report the structural and magnetic properties of the endohedral metallofullerene Ce@C82. A hexagonal close packing phase [P63/mmc [a=11.1544Å, c=18.2256Å] is formed exclusively after vacuum annealing of the solvent precipitated compound. In contrast, sublimed Ce@C82 was found to be dominantly face-centred cubic close packed [Fm-3m; a=15.766Å]. X-ray powder profile calculations revealed that the endohedral cerium atom lies close to 1.8Å from the C82 cage centre in both phases. Hexagonal Ce@C82 has been investigated by magnetic susceptibility measurements. Paramagnetic behaviour is maintained down to 2K attributable to Ce3+ ions. Towards lower temperatures, the observed paramagnetic moment falls from the free ion Ce3+(μeff =2.54μB) value, monotonically approaching 1μB at 2K. 相似文献
69.
Tanaka N Suto S Ishiyama H Kubota T Yamano A Shiro M Fromont J Kobayashi J 《Organic letters》2012,14(13):3498-3501
Two new structurally unique dimeric sesquiterpenoids, halichonadins K (1) and L (2), were isolated from an Okinawan marine sponge Halichondria sp. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis including a single crystal X-ray diffraction analysis and chemical conversion. Halichonadins K (1) and L (2) are homodimers of the eudesmane sesquiterpene linked with a piperidine ring through amide bonds. Halichonadin K (1) showed moderate cytotoxicity against KB cells. 相似文献
70.
Misaki Katayama Koichi Sumiwaka Kazuhiro Hayashi Kazuhiko Ozutsumi Toshiaki Ohta Yasuhiro Inada 《Journal of synchrotron radiation》2012,19(5):717-721
A two‐dimensional imaging system of X‐ray absorption fine structure (XAFS) has been developed at beamline BL‐4 of the Synchrotron Radiation Center of Ritsumeikan University. The system mainly consists of an ionization chamber for I0 measurement, a sample stage, and a two‐dimensional complementary metal oxide semiconductor (CMOS) image sensor for measuring the transmitted X‐ray intensity. The X‐ray energy shift in the vertical direction, which originates from the vertical divergence of the X‐ray beam on the monochromator surface, is corrected by considering the geometrical configuration of the monochromator. This energy correction improves the energy resolution of the XAFS spectrum because each pixel in the CMOS detector has a very small vertical acceptance of ~0.5 µrad. A data analysis system has also been developed to automatically determine the energy of the absorption edge. This allows the chemical species to be mapped based on the XANES feature over a wide area of 4.8 mm (H) × 3.6 mm (V) with a resolution of 10 µm × 10 µm. The system has been applied to the chemical state mapping of the Mn species in a LiMn2O4 cathode. The heterogeneous distribution of the Mn oxidation state is demonstrated and is considered to relate to the slow delocalization of Li+‐defect sites in the spinel crystal structure. The two‐dimensional‐imaging XAFS system is expected to be a powerful tool for analyzing the spatial distributions of chemical species in many heterogeneous materials such as battery electrodes. 相似文献