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621.
Synthesis of Nanoporous Carbon–Cobalt‐Oxide Hybrid Electrocatalysts by Thermal Conversion of Metal–Organic Frameworks
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Dr. Watcharop Chaikittisilp Dr. Nagy L. Torad Dr. Cuiling Li Dr. Masataka Imura Dr. Norihiro Suzuki Dr. Shinsuke Ishihara Prof. Dr. Katsuhiko Ariga Prof. Dr. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(15):4217-4221
Nanoporous carbon–cobalt‐oxide hybrid materials are prepared by a simple, two‐step, thermal conversion of a cobalt‐based metal–organic framework (zeolitic imidazolate framework‐9, ZIF‐9). ZIF‐9 is carbonized in an inert atmosphere to form nanoporous carbon–metallic‐cobalt materials, followed by the subsequent thermal oxidation in air, yielding nanoporous carbon–cobalt‐oxide hybrids. The resulting hybrid materials are evaluated as electrocatalysts for the oxygen‐reduction reaction (ORR) and the oxygen‐evolution reaction (OER) in a KOH electrolyte solution. The hybrid materials exhibit similar catalytic activity in the ORR to the benchmark, commercial, Pt/carbon black catalyst, and show better catalytic activity for the OER than the Pt‐based catalyst. 相似文献
622.
Highly Crystallized Nanometer‐Sized Zeolite A with Large Cs Adsorption Capability for the Decontamination of Water
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Nagy L. Torad Dr. Masanobu Naito Dr. Junichi Tatami Dr. Akira Endo Sin‐Yen Leo Dr. Shinsuke Ishihara Dr. Kevin C.‐W. Wu Dr. Toru Wakihara Dr. Yusuke Yamauchi 《化学:亚洲杂志》2014,9(3):759-763
Nanometer‐sized zeolite A with a large cesium (Cs) uptake capability is prepared through a simple post‐milling recrystallization method. This method is suitable for producing nanometer‐sized zeolite in large scale, as additional organic compounds are not needed to control zeolite nucleation and crystal growth. Herein, we perform a quartz crystal microbalance (QCM) study to evaluate the uptake ability of Cs ions by zeolite, to the best of our knowledge, for the first time. In comparison to micrometer‐sized zeolite A, nanometer‐sized zeolite A can rapidly accommodate a larger amount of Cs ions into the zeolite crystal structure, owing to its high external surface area. Nanometer‐sized zeolite is a promising candidate for the removal of radioactive Cs ions from polluted water. Our QCM study on Cs adsorption uptake behavior provides the information of adsorption kinetics (e.g., adsorption amounts and rates). This technique is applicable to other zeolites, which will be highly valuable for further consideration of radioactive Cs removal in the future. 相似文献
623.
Controlled Crystallization of Cyano‐Bridged Cu–Pt Coordination Polymers with Two‐Dimensional Morphology
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Mohamed B. Zakaria Dr. Ming Hu Dr. Yoshihiro Tsujimoto Prof. Yoshio Sakka Dr. Norihiro Suzuki Yuichiro Kamachi Dr. Masataka Imura Dr. Shinsuke Ishihara Prof. Katsuhiko Ariga Prof. Yusuke Yamauchi 《化学:亚洲杂志》2014,9(6):1511-1514
Two‐dimensional (2D) coordination polymers (CPs) have a highly accessible surface area that permits guest molecules to effectively access the micropores in the CPs. Here we report a bottom‐up synthesis of 2D cyano‐bridged Cu–Pt CP nanoflakes using trisodium citrate as a chelating agent, which controls the nucleation rate and the crystal growth. The lateral sizes of the CP nanoflakes are controlled by changing the amount of trisodium citrate used. We strongly believe that our method will be useful for the preparation of other types of 2D CP nanoflakes. The 2D CPs have many active sites for catalytic and electrochemical reactions, and furthermore the assembled CPs can be used as membrane filters. 相似文献
624.
Satoh S Shindoh M Min JZ Toyo'oka T Fukushima T Inagaki S 《Analytica chimica acta》2008,618(2):210-217
The direct determination of lipoyllysine (LLys) in proteins was carried out by reversed-phase high-performance liquid chromatography with fluorescence (FL) detection. The proteins containing α-lipoic acid (LA) were first hydrolyzed with several enzymes such as pronase E and subtilisin A. The disulfide bond (-S-S-) in LLys liberated from the enzyme digestion was reduced with tris(2-carboxyethyl)phosphine to the thiol form (-SH). The reduced LLys was then labeled with ammonium 4-fluoro-2,1,3-benzoxadiazole-7-sulfonate (SBD-F) at 50 °C for 1 h. The resulting fluorophore, SBD-LLys, was separated by reversed-phase chromatography and fluorometrically detected at 510 nm (excitation at 380 nm). The calibration curve obtained from the peak areas versus the injection amounts of LLys showed a good linearity. The limits of detection and quantification of LLys on the chromatogram were approximately 0.13 pmol (signal-to-noise ratio (S/N) = 3) and 0.44 pmol (S/N = 10), respectively. A good recovery (98.9-107.1%) and precision (R.S.D.: 4.49-17.2%) of LLys were also obtained using the present procedure. The proposed method was used for the determination of LLys in spinach and animal tissues. The FL derivative was completely separated without any interference by endogenous substances in the sample and sensitively detected by the fluorimetry. The assay values of LLys per 1 g wet tissues were 3.67 μg (kidney), 1.97 μg (liver), 2.09 μg (heart), 0.59 μg (brain), 0.30 μg (lung), 0.38 μg (pancreas), and 0.20 μg (spleen). The direct determination of LLys in protein using the FL labeling method is reported for the first time. 相似文献
625.
We have found that unreactive and insoluble polymeric iodosobenzene [PhIO] n induced aqueous benzylic C-H oxidation to effectively give arylketones, in the presence of KBr and montmorillonite-K10 (M-K10) clay. Water-soluble and reactive species 1 having the unique I(III)-Br bond, in situ generated from [PhIO]n and KBr, was considered to be the key radical initiator during the reactions. 相似文献
626.
Anion-exchange porous sheets were prepared by radiation-induced graft polymerization and subsequent chemical modifications. A diethylamino (DEA) group as an anion-exchange group was introduced into the polymer chain grafted onto a porous sheet. The DEA group-introduced porous sheet was cut into disks 13 mm in diameter and 3 mm in thickness to fit an empty cylindrical cartridge (DEA cartridge). The DEA sheet had a DEA group of 3.4 mol/kg of the DEA-group-containing porous sheet and a linear velocity of 46 m/h at a permeation pressure of 0.1 MPa at 298 K. The adsorption capacity of the DEA cartridge for FeCl4− as a model ion in equilibrium with 1 g-Fe(III)/L in 10 M HCl was 0.17 mmol-Fe(III)/DEA cartridge. No Pu leakage during the permeation of 5 mL of 10 M HCl-0.1 M HNO3 containing Pu ionic species through the DEA cartridge was observed irrespective of the permeation rate ranging from 0.3 to 80 mL/min. A solution containing known amounts of 233U, 240Pu, and 241Am in 10 M HCl-0.1 M HNO3 was loaded onto the DEA cartridge. U and Pu were retained on the DEA cartridge, while Am was allowed to pass through the DEA cartridge. Subsequently, 7 M HNO3 and 1 M HCl as eluents were permeated to elute U and Pu from the DEA cartridge, respectively. The decontamination factor of U in a Pu fraction, defined by dividing the activity of U in the feed solution by that of U in the Pu fraction, was 2.7 × 105, which is desirable for the highly accurate ICP-MS determination of Pu for samples containing both U and Pu. The method using the DEA cartridge was validated by measuring isotopic compositions and quantities of U and Pu in a spent nuclear fuel sample by double-focusing magnetic sector ICP-MS. 相似文献
627.
A novel double intramolecular iodoetherification of σ-symmetric diene acetals from (R,R)-hydrobenzoin occurred in highly diastereoselective manners to give tetrahydrofuran moieties with multiple chiral centers in a one-pot operation. The chemoselective discrimination of the two iodomethyl functions in the products was attained in various reactions. The reaction was applied to the concise asymmetric syntheses of rubrenolide and rubrynolide, in which the unit from the chiral auxiliary worked as a template to achieve the chemoselectivity and as the protecting group of the hydroxyl function. 相似文献
628.
Hitomi Tsuno Jingfeng Shen Hiroki Komatsu Dr. Norihito Arichi Prof. Dr. Shinsuke Inuki Prof. Dr. Hiroaki Ohno 《Angewandte Chemie (International ed. in English)》2023,62(35):e202307532
A gold-catalyzed cascade cyclization of naphthalene-tethered allenynes gave strained fused phenanthrene derivatives. The reaction proceeds through the nucleophilic reaction of an alkyne with the activated allene to generate a vinyl cation intermediate, followed by arylation with a tethered naphthalene ring to form the 4H-cyclopenta[def]phenanthrene (CPP) scaffold. When using aryl-substituted substrates on the alkyne terminus, the gold-catalyzed reaction produced dibenzofluorene derivatives along with the CPP derivatives. Selective formation of CPP and dibenzofluorene derivatives depending on the reaction conditions is also presented. 相似文献
629.
Poly(amidoamine) (PAMAM) dendrimers showed high CO2 separation properties and were successfully immobilized in a poly(ethylene glycol) (PEG) network upon photopolymerization of PEG dimethacrylate. The PAMAM dendrimer incorporation ratio was readily controlled, and a stable self-standing membrane containing up to 75 wt.% PAMAM dendrimer was obtained. The CO2 separation properties over smaller H2 were investigated by changing the PAMAM dendrimer content or generation and CO2 partial pressure (ΔPCO2) under atmospheric conditions. Especially, a polymeric membrane containing 50 wt.% PAMAM dendrimer (0th generation) exhibited an excellent CO2/H2 selectivity of 500 with CO2 permeability of 2.74 × 10−14 m3(STP)m/(m2 s Pa) or 3.65 × 103 barrer (1 barrer = 7.5 × 10−18 m3(STP)m/(m2 s Pa)) when a mixture gas (CO2/H2: 5/95 by vol.) was fed at 25 °C and 100 kPa with 80% relative humidity. This polymeric materials are promising for a novel CO2 separation membrane. 相似文献
630.
Shinsuke Inagi Takahiro Sawamura Toshio Fuchigami 《Electrochemistry communications》2008,10(8):1158-1160
Anodic fluorination of ethyl α-(2-pyrimidylthio)acetate in neat ionic liquid hydrogen fluoride salts (Et3N–3HF, Et4NF–4HF, Et4NF–5HF) was investigated to avoid an anode passivation, which sometimes occurs during anodic fluorination in organic solvent. In order to improve the yield of fluorinated product, polyether having coordination ability to cation and anodic stability was introduced to the reaction system as additives (3%). Furthermore, such additives were found to be also effective for anodic fluorodesulfurization of 4-phenylthio-1,3-dioxolan-2-one in neat ionic liquid system. 相似文献