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221.
Carmen Stavarache Rokura Nishimura Yasuaki Maeda Mircea Vinatoru 《Central European Journal of Chemistry》2003,1(4):339-355
Sonolysis of aqueous solution of chlorobenzene at 200 kHz frequency in the presence of transition metals chlorides was investigated.
Through analyzing the nature and distribution of the products detected in the reaction mixture, a new mechanism of sonodegradation
is advanced. Depending on the metals used and their behavior during sonolysis, we were able to discriminate between inside
and outside cavitation bubble mechanisms. Iron and cobalt chlorides, which could undergo redox reactions in the presence of
HO radicals generated ultrasonically, give higher amounts of phenolic compounds compared with palladium chloride that undergoes
a reduction to metal. Palladium reduction takes place in bulk solution and therefore all organic reactions that compete for
hydrogen must occur also in bulk solution. Accordingly, palladium can be a useful tool in determining the reaction site and
the decomposition mechanism of organic compounds under ultrasonic irradiation. 相似文献
222.
Tetsuji Kametani Kazuo Kigasawa Mineharu Hiiragi Kikuo Wakisaka Osamu Kusama Hideo Sugi Kumeo Kawasaki 《Journal of heterocyclic chemistry》1977,14(7):1175-1182
1H- and 2H-Pyrazolo[3,4-f]quinolines were synthesized in order to get an antibacterial compound by two different methods from 6-nitro- and 6-aminoindazole. 相似文献
223.
Hiroshi Tanida Tadashi Irie Yoshiharu Wakisaka 《Journal of heterocyclic chemistry》1986,23(1):177-181
Treatment of 5,6,7,8-tetrahydro-5,8-methanoisoquinoline N-oxide ( 2 ) with fuming nitric acid afforded 3-nitro-5,6,7,8-tetrahydro-5,8-methanoisoquinoline N-oxide ( 3 ), an example of formation of an α-nitropyridine N-oxide derivative by nitration of N-oxides. Further reaction of 3 resulted in deoxygenation giving 3-nitro-5,6,7,8-tetrahydro-5,8-methanoisoquinoline ( 4 ). No aromatic nitration was observed by similar treatment of 5,6,7,8-tetrahydro-5,8-methanoisoquinoline ( 1 ) or 5,6,7,8-tetrahydroisoquinoline N-oxide ( 11 ). Some other aromatic substitutions with 1 and 2 were caried out to obtain mainly the 3-substituted derivatives. Significant mutagenicity of 3 is briefly reported. 相似文献
224.
Takeshi Kubota Naoto Hosomi Yuya Hamasaki Yasuaki Okamoto 《Chemical physics letters》2003,370(5-6):813-819
The S–Se exchange during the hydrode-selenium (HD-Se) reaction of selenophene was investigated over MoS2/Al2O3 and intrazeolite Mo sulfide clusters. The local structure of Se incorporated into the Mo sulfide catalysts was studied by means of Se K-edge XAFS. It was found that the capacity of S–Se exchange during the HD-Se reaction and dynamic behavior of Se incorporation strongly depend on the cluster size of Mo sulfides. 相似文献
225.
A column of iminodiacetate chelating resin is used to preconcentrate cadmium by a factor of 25-fold for a 5-ml sample. The sampling rate was 25 h?1, and the detection limit 0.05 ng Cd2+ ml?1. The r.s.d. for 0.1 μg Cd2+ ml?1 was 2.2% (n = 10). This technique was applied to the determination of cadmium in certified biological reference materials and waste-water samples. 相似文献
226.
Yoshihiro Itoh Kazuyoshi Wakisaka Koji Abe Saburo Senoh 《Journal of polymer science. Part A, Polymer chemistry》1987,25(5):1383-1394
Reduction of crystal violet (CV) by poly(sodium styrene-p,-sulfonate) containing dihydronicotinamide (NAH) groups (PNAH) was compared with that by poly(sodium 2-acrylamido-2-methylpropanesulfonate) containing NAH groups (PNAH-AMPS) in aqueous media. PNAH reduced CV far more effectively than PNAH-AMPS, suggesting the presence of both hydrophobic and electrostatic interaction between PNAH and CV. An obvious color change was observed on addition of CV to the polyelectrolyte solutions, which was largely affected by the kind of polymers and the experimental conditions such as ionic strength and medium composition. These results imply that the location of CV within the macromolecular domain is an important factor for the polyelectrolyte-induced metachromasy. Some correlations of the metachromatic behaviors of CV with the reduction were also discussed. 相似文献
227.
Yoshihiro Itoh Kazuyoshi Wakisaka Yutaka Matsuda Koji Abe Saburo Senoh 《Journal of polymer science. Part A, Polymer chemistry》1987,25(3):745-752
Reduction of charged or uncharged substrates by a copolymer of N-(p-vinylbenzyl)-1,4-dihydronicotinamide and sodium styrene-p-sulfonate (PNAH) in aqueous solutions was investigated. Electrostatic interaction of PNAH with charged substrates led to a far more effective reduction of crystalviolet (CV) and a far less effective reduction of potassium ferricyanide (FeC) than the monomer model [N-benzyl-1,4-dihydronicotinamide (BNAH)] system. In the PNAH-CV system, in particular, a rapid reduction occurs by a first-order process because of the remarkable concentration effect of the polymer. Furthermore, this reduction was not appreciably affected by an added salt, suggesting the presence of hydrophobic interaction between PNAH and CV. 相似文献
228.
A signals ratio method combined with wavelet transform was proposed for the resolution of a weak voltammetric signal overlapped by other components. The signals ratio method usually suffers from interference from noise and baseline contained in the original signals because these factors cause distortion of the signals ratio. The multiresolution capability of the wavelet transform method was exploited here to simultaneously remove or reduce the noise and background. As a result, a deformation-free signals ratio with good signal-to-noise ratio (SNR) was obtained even for very noisy signals. The properties of the proposed method were compared to other resolution methods. It was demonstrated that the combined signals ratio wavelet transform method was particularly applicable to resolve a minor component in the presence of large amount of other components, suggesting that it can provide improved detection limits and quantified results for minor components. The method was employed for the voltammetric determination of residual chlorine in the presence of N,N-diethyl-p-phenylenediamine (DPD). 相似文献
229.
The mannose monosaccharide derivative, acetylthiopropyl 2,3,4,6-tetra-O-acetyl-α-d-mannopyranoside (Man), and the mannobiose derivative, acetylthiopropyl 2,4,6-tri-O-acetyl-3-O-(2′,3′,4′,6′-tetra-O-acetyl-α-d-mannopyranosyl)-α-d-mannopyranoside (α-1,3-Man), were synthesized respectively. These mannose derivatives were introduced into carbosilane dendrimer scaffolds of the zero and first generations. As a result, six carbosilane dendrimers were functionalized by Man and α-1,3-Man. Isothermal titration microcalorimetry was done to determine binding assay between mannose moieties of carbosilane dendrimer and concanavalin A. It was found that carbosilane dendrimers bound more efficiently to concanavalin A than free mannose (Me-α-Man) and mannobiose (Me-α-1,3-Man). 相似文献
230.
We have systematically investigated the structural features, electronic properties, thermally-induced structural phase transitions and absorption spectra depending on the solvent for ten Cu(II) complexes with 3,5-halogen-substituted Schiff base ligands. Structural characterization of two new complexes, bis(N-R-1-phenylethyl- and N-R,S-2-butyl-5-bromosalicydenaminato-κ2N,O)copper(II), reveals that they afford a compressed tetrahedral trans-[CuN2O2] coordination geometry with trans-N–Cu–N = 159.4(2)° and trans-O–Cu–O = 151.7(3)° for the 1-phenylethyl complex and trans-N–Cu–N = 157.9(3)° and trans-O–Cu–O = 151.0(3)° for the 2-butyl one. All the complexes exhibit a structural phase transition by heating in the solid state regardless of their structures at room temperature. The absorption spectra of a series of ten complexes exhibit a slight shift of the d–d band at 16 000–20 000 cm−1 and remarkable shift of the π–π* band at 24 000–28 000 cm−1, which suggests that the dipole moment of the solvents presumably affects the conformation of the π-conjugated moieties of the ligands rather than the coordination environment. We have also attempted ‘photochromic solute-induced solvatochromism’ by a system of bis(N-R-1-phenylethyl-3,5-dichlorosalicydenaminato-κ2N,O)copper(II) and photochromic 4-hydroxyazobenzene in chloroform solution. We successfully observed a change of the d–d and π–π* bands of the complex in the absorption spectra caused by cis–trans photoisomerization of 4-hydroxyazobenzene. 相似文献