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31.
32.
Yamauchi A Sakashita Y Hirose K Hayashita T Suzuki I 《Chemical communications (Cambridge, England)》2006,(41):4312-4314
Pseudorotaxane formed by reacting beta-cyclodextrin bearing a phenylboronic acid residue with 1-heptyl-4-(4'-dimethylaminostyryl)pyridinium functioned as a novel fluorescent saccharide receptor having unique responses. 相似文献
33.
Ryu I Miyazato H Kuriyama H Matsu K Tojino M Fukuyama T Minakata S Komatsu M 《Journal of the American Chemical Society》2003,125(19):5632-5633
Free-radical mediated stannylcarbonylation of azaenynes provides a general [n + 1]-type annulation approach leading to alpha-stannylmethylene lactams. The cyclization is unusual in its breadth, covering 4-exo, 5-exo, 6-exo, 7-exo, and 8-exo modes. 相似文献
34.
Tetracyanoethylene oxide (TCNEO) reacted with [CpCo(dithiolene)] (Cp = η5-cyclopentadienyl) complexes having 4-pyridyl or 3-pyridyl group to undergo a dicyanomethylation to the nitrogen atom on the pyridyl group. The reaction of [CpCo(S2C2(4Py)2)] (1) with TCNEO formed both the monodicyanomethylated [CpCo(S2C2(4Py)(4Py-C(CN)2))] (1a) and bisdicyanomethylated [CpCo(S2C2(4Py-C(CN)2)2)] (1b). [CpCo(S2C2(2Py)(4Py))] (2) reacted with TCNEO to give [CpCo(S2C2(2Py)(4Py-C(CN)2))] (2a) but no dicyanomethylation occurred on the 2-pyridyl group. 2 reacted with excess TCNEO to form the only dicyanomethylated acetylene derivative 2Py-CC-(4Py-C(CN)2) (2c), followed by a dissociation of the CpCoS2 fragment. The monodicyanomethylated [CpCo(S2C2(nPy-C(CN)2)(2-thienyl))] (n = 4 (4a) or 3 (5a)) complexes were also prepared from [CpCo(S2C2(nPy)(2-thienyl))] (n = 4 (4) or 3 (5)) and TCNEO. 1b was structurally characterized by X-ray diffraction study. The all dicyanomethylated [CpCo(dithiolene)] complexes showed the dithiolene LMCT absorption in the range of 605-644 nm (ε = 7000-9200 M−1 cm−1) and very strong absorption due to their pyridinium-dicyanomethylide moieties in near-UV region (e.g. 1b: λmax = 470 nm, ε = 43,400 M−1 cm−1). The CV of the all dicyanomethylated complexes exhibited two reduction waves. The first reduction is due to CoIII/CoII and the second one is due to the reduction of the pyridinium-dicyanomethylide moiety. The reduced 1b− is stable enough for several minutes according to the visible spectroelectrochemical measurement. The ESR spectrum of 1b− indicated eight hyperfine splittings due only to the interaction with the nuclear spin of cobalt (I = 7/2). 相似文献
35.
36.
V. A. Bogdanovskaya L. A. Beketaeva K. V. Rybalka B. N. Efremov N. M. Zagudaeva M. Sakashita T. Iidzima Z. R. Ismagilov 《Russian Journal of Electrochemistry》2008,44(3):293-302
We present the results of electrochemical and structural investigations of several carbon materials: carbon blacks AD 100 and XC 72, ultradisperse diamond (UDD), multiwalled nanotubes (MWNT), various types of filament-like carbon materials (CFC series), and similar carbon materials promoted with cobalt tetra(para-methoxyphenyl) porphyrin (CoTMPhP) pyropolymer (PP). The electrochemical studies were performed at room temperature in 0.5 M H2SO4 by using a rotating disk electrode (RDE), a rotating ring-disk electrode (RRDE) (a thin layer of test material was applied onto the disk electrode), and a floating electrode. Structural characterization of initial and promoted carbon materials involved the determination of specific surface area by the BET method and by the polarization capacitance from cyclic voltammograms, and the particle morphology and dimensions by the transmission electron microscopy (TEM) method. The study of kinetics and mechanism of oxygen electroreduction on carbon materials promoted with CoTMPhP PP showed that the catalysts based on carbon materials of CFC and UDD series possess high specific activity in this reaction and high selectivity with respect to oxygen reduction to water. These catalysts are superior to the catalysts, in which carbon blacks AD 100 and XC 72 are used as the supports, in the specific activity. 相似文献
37.
Fujihisa H Akahama Y Kawamura H Ohishi Y Shimomura O Yamawaki H Sakashita M Gotoh Y Takeya S Honda K 《Physical review letters》2006,97(8):085503
Despite many experimental and theoretical studies, the crystal structure of the epsilon phase of solid oxygen has not been determined. We performed powder x-ray diffraction experiments and the Rietveld analyses in this study to show that a new arrangement of the monoclinic space group C2/m could fit the diffraction patterns of the epsilon phase and obtained a structure that consisted of an O8 cluster with 4 molecules. The dependence of the lattice parameters, the molar volume, and the intermolecular distances on the pressure was investigated. 相似文献
38.
Brillouin scattering is an efficient nondestructive and noncontact measurement method to obtain the wave properties of thin layers at hypersonic frequencies. The reflection induced ThetaA (RIThetaA) scattering geometry enables the simultaneous measurement of the phonons, which propagate in each direction of wave vectors of q(Theta A) (propagation in the film plane) and q(180) (back scattering). Using this scattering geometry, we could observe the refractive indices and birefringence of the piezoelectric poly-vinylidene fluoride (PVDF) film as a function of temperature. By introducing the microscopic technique, the elastic anisotropy and refractive index measurements in the minute area of polycrystalline ZnO films were also performed. 相似文献
39.
Mami Miyairi Dr. Tsuyoshi Taniguchi Dr. Tatsuya Nishimura Prof. Katsuhiro Maeda 《Angewandte Chemie (International ed. in English)》2023,62(37):e202302332
Improved methods for the synthesis of linear and cyclic poly(diphenylacetylene)s by polymerization of the corresponding diphenylacetylenes using MoCl5- and WCl4-based catalytic systems have been developed. MoCl5 induces migratory insertion polymerization of diphenylacetylenes in the presence of arylation reagents such as Ph4Sn and ArSnnBu3 to produce cis-stereoregular linear poly(diphenylacetyelene)s with high molecular weights (number-average molar mass (Mn)=30,000–3,200,000) in good yields (up to 98 %). On the other hand, WCl4 induces ring expansion polymerization of diphenylacetylenes in the presence of Ph4Sn or reducing reagents to produce cis-stereoregular cyclic poly(diphenylacetylene)s with high molecular weights (Mn=20,000–250,000) in moderate to good yields (up to 90 %). Both catalytic systems are applicable to the polymerization of various diphenylacetylenes having polar functional groups such as esters that are not efficiently polymerized by conventional methods using WCl6-Ph4Sn and TaCl5-nBu4Sn systems. 相似文献
40.
Yasuko Yoshida Kentaro Iwai Kentaro Nagata Takehiko Seo Masato Mikami Osamu Moriue Tetsuya Sakashita Masao Kikuchi Takuma Suzuki Masaki Nokura 《Proceedings of the Combustion Institute》2019,37(3):3409-3416
This research conducted microgravity experiments on the flame spread over droplet-cloud elements with strong droplet interaction aboard Kibo on the ISS. The droplet-cloud element represents a local droplet pattern appearing in randomly distributed droplet clouds near the group-combustion-excitation limit and consists of small-droplet-spacing droplets and large-droplet-spacing droplets. As droplet-cloud elements, we used four n-decane droplets, Droplets C, B, A and L, placed at fiber intersections of two-dimensional SiC-fiber lattice with a 4-mm fiber interval in a combustion chamber. The flame spreads over the droplet-cloud element in order of Droplets C, B, A and L. The position of Droplet L relative to Droplet A was varied to investigate the flame-spread-limit distribution around burning Droplet A. The position of Droplet B relative to Droplet A was varied to investigate the effect of two-droplet interaction between Droplets B and A on the flame spread to Droplet L. The position of Droplet C relative to Droplet B was also varied to investigate the effect of three-droplet interaction among Droplets C, B and A. The results shows that in the case with the strong interaction by two or three interactive droplets, the high-temperature region is enlarged by the droplet interaction, centers near the center of mass of the interactive droplets and plays an important role in the flame-spread-limit distribution. Since the burning lifetime of Droplet A is finite, the flame-spread time from burning Droplet A to Droplet L is limited by burning lifetime of Droplet A and is less than 80% of the burning lifetime of Droplet A, which increases with the interactive effect. The flame-spread-limit distance from the center of mass of the interactive droplets increases with the burning lifetime. 相似文献