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481.
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483.
Kitano H Mori T Takeuchi Y Tada S Gemmei-Ide M Yokoyama Y Tanaka M 《Macromolecular bioscience》2005,5(4):314-321
The structure and hydrogen bonding of water in the vicinity of a thin film of a sulfobetaine copolymer (poly[(N,N-dimethyl-N-(3-sulfopropyl)-3'-methacrylamidopropanaminium inner salt)-ran-(butyl methacrylate)], poly(SPB-r-BMA)), were analyzed with band shapes of O-H stretching of attenuated total reflection infrared (ATR-IR) spectra. The copolymer could be cast as a thin film, of approximate thickness 10 microm, on a ZnSe crystal for the ATR-IR spectroscopy. At an early stage of sorption of water into the polymer film, the O-H stretching band of the IR spectra for the water incorporated in the film was similar to that for free water. This is consistent with the tendency for another zwitterionic polymeric material, poly[(2-methacryloyloxyethylphosphorylcholine)-ran-(butyl methacrylate)] (poly(MPC-r-BMA). It is, however, contradictory to the drastic change in the O-H stretching band for water incorporated into films of polymers such as poly(2-hydroxyethyl methacrylate), poly(methyl methacrylate) and poly(butyl methacrylate). These results suggest that polymers with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules incorporated in the thin films. The investigation into the blood-compatibility of both the poly(SPB-r-BMA) and the poly(MPC-r-BMA) films indicate a definite correlation between the blood-compatibility of the polymers and the lack of effect of the polymeric materials on the structure of the incorporated water. 相似文献
484.
固相法氯化聚乙烯对PVC/LLDPE共混体系性能和形态的影响 总被引:2,自引:0,他引:2
采用固相法氯化聚乙烯(CPE)对聚氯乙烯/线型低密度聚乙烯(PVC/LLDPE)共混体系进行增容改性。扫描电子显微镜、透射电子显微镜、动态力学分析和力学性能测试结果表明,CPE对PVC/LLDPE共混体系具有很好的增容作用。 相似文献
485.
以过氧化二异丙苯(DCP)为引发剂,甲基丙烯酸缩水甘油酯(GMA)为活性单体,高抗冲苯乙烯(HIPS)通过熔融接枝制得了动能化的高抗冲聚苯乙烯接枝物(HIPS-g-GMA)。用红外光谱和电子能谱对其结构进行了表征。HIPS-g-GMA的红外谱图,证明GMA已经接枝到HIPS上。电子能谱分析也提供了相似的结论。研究了单体浓度和DCP用量对产物接枝率的影响,并用化学滴定方法测定了接枝物的接枝率。用DSC、SEM、WAXD、DMA等研究了PBT/HIPS和PBT、HIPS-g-GMA的结晶、形态结构、动态力学性能及力学性能随组成的变化。SEM及DMA分析表明增容后体系的相容性得到改善,力学性能有较大提高。 相似文献
486.
Ana Flávia Oliveira Santos I. D. Basílio Jr F. S. de Souza A. F. D. Medeiros Márcia Ferraz Pinto D. P. de Santana R. O. Macêdo 《Journal of Thermal Analysis and Calorimetry》2008,93(2):361-364
Thermal analysis is an essential analytical tool in development of new formulations as well as to study the interaction between drugs and excipients. This work aims to investigate the possible interactions between metformin and excipients as microcrystalline cellulose (Microcel MC101®), starch sodium glycolate (Explosol®), sodium croscarmellose (Explosel®), PVP K30, magnesium stearate, starch and lactose, usually employed in pharmaceutical products. TG, DSC and DTA techniques were used for the thermal characterization to track if the thermal properties of the drug substance were modified in the mixture. Disregard of the starch and lactose systems, no changes in thermal behavior of mixtures were found. Thermogravimetric studies (TG) of metformin and its binary mixtures showed different thermal behavior. 相似文献
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The purpose of this work is to develop a biocompatible polyurethane surface by the tailoring of sulfobetaine. The polyurethane film was first grafted polymerization with acrylic acid by ozonization, followed by immobilizing sulfobetaine via two routes: (i) synthesize primary amine group terminated sulfobetaine and then couple onto the surface of polyurethane using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC); (ii) couple the primary amine group terminated tertiary amine onto the surface of polyurethane primarily using EDC and then form sulfobetaine through a ring-opening reaction between tertiary amine and 1,3-propanesultone (PS). The reaction process was monitored with attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The blood compatibility was evaluated by a hemolytic test and platelet-rich plasma (PRP) adhesion experiment. Little hemolysis took place on the surface of polyurethane grafted with sulfobetaine. Platelets adhering on the surface of grafted polyurethane decreased greatly as compared to the original after 1 and 3h of incubation with PRP. 相似文献
489.
Myriam Díaz-Álvarez Esther Turiel Antonio Martín-Esteban 《Journal of separation science》2023,46(12):2300157
Molecular imprinting technology is a well-established technique for the obtainment of tailor-made polymers, so-called molecularly imprinted polymers, with a predetermined selectivity towards a target analyte or structurally related compounds. Accordingly, molecularly imprinted polymers are considered excellent materials for sample preparation providing unprecedented selectivity to analytical methods. However, the use of molecularly imprinted polymers in sample preparation still presents some shortcomings derived from the synthesis procedure itself limiting its general applicability. In this regard, molecularly imprinted polymers use to display binding sites heterogeneity and slow diffusion mass transfer of analytes to the imprinted sites affecting their overall performance. Besides, the performance of molecularly imprinted polymers in organic solvents is excellent, but their selective binding ability in aqueous media is considerably reduced. Accordingly, the present review pretends to provide an updated overview of the recent advances and trends of molecularly imprinted polymers-based extraction, focusing on those strategies proposed for the improvement of mass transfer and selective recognition in aqueous media. Besides, with the progressive implementation of Green Chemistry principles, the different steps and strategies for the preparation of molecularly imprinted polymers are reviewed from a green perspective. 相似文献
490.
H2O2 is a widely occurring molecule which is also a byproduct of a number of enzymatic reactions. It can therefore be used to quantify the corresponding enzymatic substrates. In this study, the time-resolved fluorescence emission of a previously described complex consisting of phthalic acid and terbium (III) ions (PATb) is used for H2O2 detection. In detail, glucose oxidase and choline oxidase convert glucose and choline, respectively, to generate H2O2 which acts as a quencher for the PATb complex. The response time of the PATb complex toward H2O2 is immediate and the assay time only depends on the conversion rate of the enzymes involved. The PATb assay quantifies glucose in a linear range of 0.02–10 mmol L−1, and choline from 1.56 to 100 μmol L−1 with a detection limit of 20 μmol L−1 for glucose and 1.56 μmol L−1 for choline. Both biomolecules glucose and choline could be detected without pretreatment with good precision and reproducibility in human serum samples and infant formula, respectively. Furthermore, it is shown that the detected glucose concentrations by the PATb system agree with the results of a commercially available assay. In principle, the PATb system is a universal and versatile tool for the quantification of any substrate and enzyme reaction where H2O2 is involved. 相似文献