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1.
Capacity Constrained Transit Assignment with Common Lines 总被引:1,自引:0,他引:1
Fumitaka Kurauchi Michael G. H. Bell Jan-Dirk Schmöcker 《Journal of Mathematical Modelling and Algorithms》2003,2(4):309-327
This paper proposes the use of absorbing Markov chains to solve the capacity constrained transit network loading problem taking
common lines into account. The approach handles congested transit networks, where some passengers will not be able to board
because of the absence of sufficient space. The model also handles the common lines problem, where choice of route depends
on frequency of arrivals. The mathematical formulation of the problem is presented together with a numerical example.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
3.
4.
5.
Meyers CY Chan-Yu-King R Hua DH Kolb VM Matthews WS Parady TE Horii T Sandrock PB Hou Y Xie S 《The Journal of organic chemistry》2003,68(2):500-511
Most alkyl phenyl sulfones are readily alpha-chlorinated with CCl(4) and alpha-brominated with CBrCl3 in KOH-t-BuOH via radical-anion radical pair (RARP) reactions. While isopropyl mesityl sulfone (4) is easily alpha-chlorinated with CCl(4), it was completely recovered when treated with the more reactive CBrCl3. Subsequent investigations showed the latter result to be due to the poor acidity of 4 together with the rapid depletion of CBrCl3 and KOH by their reaction with each other, and led to a variety of other important results. 4-Hydroxyphenyl isopropyl sulfone (6) is unreactive with either CCl4 or CBrCl3 in KOH-t-BuOH, its phenoxide anion strongly reducing the electronegativity of the sulfonyl group, thereby inhibiting alpha-anion formation. This effect is reversed by the electron-withdrawing influence of two alpha-phenyls, so that benzhydryl 4-hydroxyphenyl sulfone (8) is readily alpha-halogenated in KOH-t-BuOH with CCl4 or CBrCl3. On further contact with KOH-t-BuOH the alpha-halogenated sulfones from 8 are decomposed into benzophenone and phenol. While the alpha-halogenated derivatives of 4-methoxyphenyl benzhydryl sulfone (9) are stable to base, they are decomposed even under mildly acidic conditions into 4-methoxyphenyl 4-methoxybenzenethiolsulfonate (9c), phenol, and benzophenone. Mono-alpha-halogenation of benzyl phenyl sulfone (10) enhances the rate of the subsequent halogenation, so that alpha,alpha-dihalogenation is attained while much substrate is still present and the mono-alpha-halogenated product is not detected. The ease of reductive debromination of alpha-bromo sulfones with Cl3C- was correlated with the stability of the formed alpha-anions, explaining the success with alpha-bromobenzylic sulfones but failure with alpha-bromoalkyl sulfones. In the presence of air and the absence of competing halogenation, formation of the alpha-anions of alkyl aryl sulfones is quickly accompanied by oxidative cleavage by atmospheric O2, leading to the formation of arenesulfonyl alcohols, arenesulfonyl halides, and haloarenes. 相似文献
6.
Tatsuro Ouchi Hidetake Miyazaki Hidetoshi Arimura Fumitaka Tasaka Atsushi Hamada Yuichi Ohya 《Journal of polymer science. Part A, Polymer chemistry》2002,40(10):1426-1432
Amphiphilic AB‐type diblock copolymers composed of hydrophobic poly(L ‐lactide) (PLA) segments and hydrophilic poly(glycolic acid lysine) [poly(Glc‐Lys)] segments with amino side‐chain groups self‐associated to form PLA‐based polymeric micelles with amino surfaces in an aqueous solution. The average diameter of the loose core–shell polymeric micelles for poly(Glc‐Lys) [number‐average molecular weight (Mn) = 1240]‐b‐PLA (Mn = 7000) obtained by a dimethyl sulfoxide/water dialysis method was estimated to be about 50 nm in water by dynamic light scattering measurements. The size and shape of the obtained polymeric micelles were further observed with transmission electron microscopy and atomic force microscopy. To investigate the possibility of applying the obtained PLA‐based polymeric micelles as bioabsorbable vehicles for hydrophobic drugs, we tested the entrapment of drugs in poly(Glc‐Lys) (Mn = 1240)‐b‐PLA (Mn = 7000) micelles and their release with doxorubicin as a hydrophobic drug. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1426–1432, 2002 相似文献
7.
Masahisa Wada Takeshi Okano Junji Sugiyama Fumitaka Horii 《Cellulose (London, England)》1995,2(4):223-233
We have investigated unlignified tension wood and normally lignified wood celluloses inPopulus maximowiczii with particular reference to the composition of two crystalline phases I/I (triclinic/ monoclinic). Four independent techniques, which enable us to detect the two phases, CP/MAS13C NMR, Fourier transform infrared microscopy, selected-area electron diffraction, and X-ray diffraction were applied. Because of the low crystallinity of wood celluloses, particularly in the case of celluloses in the lignified cell wall, no single method was decisive enough to be able to determine the composition of the two phases as one can with highly crystalline materials. The I dominant structure (monoclinic crystal type) was, however, preferred for both tension and normal wood celluloses. 相似文献
8.
A new infrared-spectroscopic method to characterize acid sites of zeolites using small and weakly basic molecules such as diatomic and monoatomic molecules is reviewed. It has been revealed that N2 is an effective probe molecule to characterize both Brønsted acidity and Lewis acidity of H-form zeolites. The characteristics of the N 2 probe are discussed in detail in comparison with the CO probe. O2 and rare gases have also been applied to monitor the strong acid sites in the H-form zeolites. Further, the studies of the adsorption of water on H-form zeolites are shortly reviewed: a recent IR study of the H2
18O adsorption on H-ZSM-5 has given direct experimental evidence that the main feature of the observed IR bands is due to the hydrogen-bonded adsorption of water on the Brønsted acid sites. 相似文献
9.
Spirobenzopyran 1 , with the 3-(diethoxymethylsilyl)-propyl group at the N atom, was synthesized. The condensation reaction of the spiropyran 1 and diethoxydimethylsilane gave oligomeric poly(dimethylsiloxane) with the spiropyran moiety in the side chain. The oligomer was photochromic; its colour changed from colorless to purple-red on uv irradiation and the color faded on visible irradiation or on standing in the dark. The half-decay time of the thermal decoloration was about twice that of monomeric spiropyran dissolved in the dimethylsiloxane oligomer. Photochromic poly(dimethylsiloxane) with the spirooxazine moiety in the side chain was also prepared. 相似文献
10.
Shinji Suzuki Furitsu Suzuki Yasumasa Kanie Koji Tsujitani Asako Hirai Hironori Kaji Fumitaka Horii 《Cellulose (London, England)》2012,19(3):713-727
The structure and crystallization of carefully isolated sub-elementary fibrils (SEFs) of bacterial cellulose have been investigated
using TEM, WAXD, and high-resolution solid-state 13C NMR. The addition of a suitable amount of fluorescent brightener (FB) to the incubation medium of Acetobacter xylinum effectively suppressed the aggregation of the SEFs into the microfibrils, as previously reported. However, this study confirmed
for the first time that serious structural change in the SEFs occurs during the removal of excess FB by washing with buffer
solutions having pH values higher than 6 or with the alkaline aqueous solution that was frequently used in previous studies.
In contrast, the isolation of unmodified SEFs was successfully performed by utilizing a washing protocol employing pH 7 citrate–phosphate
buffer solution containing 1% sodium dodecyl sulfate. High-resolution solid-state 13C NMR and WAXD measurements revealed that the SEFs thus isolated are in the noncrystalline state in which the pyranose rings
of the almost parallel cellulose chains appear to be stacked on each other. The respective CH2OH groups of the SEFs adopt the gt conformation instead of the tg conformation found in cellulose I
α
and I
β
crystals, and undergo significantly enhanced molecular motion in the absence of intermolecular hydrogen bonding associated
with these groups. The main chains are also subject to rapid motional fluctuations while maintaining the parallel orientation
of the respective chains, indicating that the SEFs have a liquid crystal-like structure with high molecular mobility. Moreover,
the SEFs crystallize into cellulose I
β
when the FB molecules that may adhere to the surface of the SEFs are removed by extraction with boiling 70 v/v% ethanol and
0.1N NaOH aqueous solution. On the basis of these results, the crystallization of the SEFs into the I
α
and I
β
forms is discussed, including the possible formation of the crystalline-noncrystalline periodic structure in native cellulose. 相似文献