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121.
We prepared TiO2–ZrO2 binary oxide particles with various Ti/(Zr+Ti) mole ratios (x) from the solutions containing Ti(OC3H7i)4, Zr(OC3H7n)4 and acetylacetone (acac). The spherical particles of 1–5 μm in diameter were obtained via solvothermal treatment at 150 °C. The spheres were anatase at x=1 and amorphous at x=0–0.8. The spheres were thought to be formed through the moderate hydrolysis and nucleation provided by the chelation of the alkoxides by acac. Crystalline TiO2–ZrO2 particles were obtained by the heat treatment of the as-precipitated spheres, and the crystalline phase changed with the Ti/(Zr+Ti) mole ratios. Pure ZrO2 and TiO2, ZrO2 doped with Ti4+, TiO2 doped with Zr4+ and ZrTiO4 phases were produced, and the spherical shape remained after the heat treatment at 500–750 °C. 相似文献
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124.
Shinya Oda Hiroaki Uchiyama Hiromitsu Kozuka 《Journal of Sol-Gel Science and Technology》2014,70(3):441-450
Titanium tetra-n-butoxide was hydrolyzed in the presence of benzoylacetone (BzAc), and the solution obtained was concentrated and served for spin-coating or dropping on substrates, followed by successive drying at 120, 200 and 250 °C. The dried products were transparent and amorphous, and the infrared absorption and Raman spectroscopic studies showed that BzAc forms chelate rings. Thermomechanical analysis showed that the 120 and 200 °C-dried products showed steep, thermoplastic shrinkage at around 30 and 70–85 °C, respectively, whereas the 250 °C-dried product did not show thermoplasticity. Thus as the drying temperature was increased, the thermoplasticity appeared at a higher temperature and finally disappeared. These changes in thermoplasticity with drying temperature were concluded to result from the progress of condensation between titanoxane polymers and/or clusters, which was evidenced in gel permeation chromatographic analysis. 相似文献
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126.
Seizo Tamagaki Ryuji Akatsuka Mitsuyoshi Nakamura Seizi Kozuka 《Tetrahedron letters》1979,20(38):3665-3668
The photo-oxygenation of the title compound leads to the corresponding ketone and sulfine. A mechanism for the reaction is elucidated. 相似文献
127.
Kentaro Hirai Hirohiko Sugimoto Teruyuki Ishiba Toshio Fujishita Yuji Tsukinoki Katsumi Hirose 《Journal of heterocyclic chemistry》1982,19(6):1363-1369
The synthesis of (5-acylaminomethyl-3-carbamoyl-1H-1,2,4-triazol-1-yl)benzophenone derivatives 4a-i, 14a-d, 15a-d, 16a-c , is described. Acylation of the key intermediate, 1-benzoylphenylazo-1-aminoacetamide 7, followed by cyclization in the presence of acid afforded 1H-1,2,4-triazole derivatives. These compounds were evaluated for their central nervous system (CNS) activity. Some of these compounds exhibited high activities in anti-pentylene tetrazole and rotarod test in mice when orally administered. 相似文献
128.
[reaction: see text] Addition of aniline derivatives to aromatic and aliphatic alkynes proceeds efficiently in the presence of a gold(I) catalyst (0.01-1.0 mol %) to afford ketimines in good yields 相似文献
129.
Mimura H Gato K Kitamura S Kitagawa T Kohda S 《Chemical & pharmaceutical bulletin》2002,50(6):766-770
This study clearly demonstrates that clathrated water molecules can contribute to both chemical stabilization and destabilization of clathrates. The solid-state stabilities for two isomorphic clathrates of cephalosporin, cefazolin sodium and FK041, were investigated in terms of the effects of water content. The isomorphic ranges of water content were estimated to be 3.5-5 mol/mol for alpha-form cefazolin sodium and 2-4 mol/mol for FK041 hydrate. Upon the isomorphic dehydration, alpha-form cefazolin sodium was destabilized as the water content decreased below 4.25 mol/mol owing to the disruption of hydrogen bonding network in lattice channels. In this case, the hydration of clathrated water up to 4.25 mol/mol contributed to the physical and chemical stability of the crystals. On the contrary, the isomorphic hydration in FK041 hydrate contributed to the chemical destabilization owing to the high water activity. The difference in water activity between alpha-form cefazolin sodium and FK041 hydrate could be attributed to the size of water channels. 相似文献
130.
Komatsu T Moritake M Tsuchida E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(19):4626-4633
Novel molecular energy and electron transfer assemblies in vesicular form, which are made of self-organized amphiphilic porphyrins bearing phospholipid-like substituents (lipid-porphyrins), have been photochemically characterized. Tetraphenylporphyrin (TPP) derivatives with four dialkylphosphocholine groups [free-base (1 a), Zn(2+) complex (1 b), and Fe(3+) complex (1 c)] are spontaneously associated in water to form spherical unilamellar vesicles with a diameter of 100-150 nm. Exciton calculations based on the bilayered sheet model of 1 b, which has a porphyrin packing similar to that seen in the triclinic unit cell of the Zn(2+)TPP crystals, reproduced the Soret band bathochromic shift appearing in the aqueous solution of 1 b well. The UV/Vis absorption spectrum of the 1 a/1 b hybrid vesicles (molar ratio: 1/1) showed no electronic interaction between the two porphyrin chromophores in the ground state, but efficient intermolecular singlet-singlet energy transfer took place from the excited 1 b donors to the 1 a acceptor within the vesicle. Near-field scanning optical microspectroscopy of the 1 a/1 b vesicles on a graphite surface also showed only free-base porphyrin fluorescence. The efficiency of the energy transfer was 0.81 and the rate constant was 3.1 x 10(9) s(-1). On the other hand, protoporphyrin IX bearing two alkylphosphocholine propionates (2) was incorporated into the 1 a or 1 c bilayer vesicles (ca. 100 nm phi, molar ratio: 1 a/2 or 1 c/2=10). The UV/Vis absorption spectrum showed that 2 was successfully anchored into the fluid alkylene region of the membrane without stacking. Photoirradiation (lambda(ex): 390 nm) of the 1 c/2 vesicles in the presence of triethanolamine led a vectorial electron transfer from the outer aqueous phase to the membrane center, which allowed reduction of the ferric ion of the Fe(3+)TPP platform. 相似文献