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81.
Zhaohui Huang Lika Yang Xiaoqing Hu Yiqian Huang Qing Cai Yingfang Ao Xiaoping Yang 《Macromolecular bioscience》2019,19(6)
Amino acid ester substituted polyphosphazenes are osteoactive benefiting from their phosphorus‐containing chemical structure, which highlights interests in bone tissue engineering. To correlate their chemical structures with cell activities, in this study, poly[(ethyl alanato)0.3(ethyl glycinato)0.7phosphazene] (PAGP) and poly[(ethyl phenylalanato)0.3(ethyl glycinato)0.7phosphazene] (PPGP) are synthesized to carry out studies on cell osteogenic differentiation. In the non‐contact culture manner, bone mesenchymal stromal cells (BMSCs) are cultured in transwell chambers containing PAGP or PPGP films, while the cells and the materials do not contact. In the contact culture manner, BMSCs are cultured on the PAGP or PPGP films. In the meantime, solutions containing PAGP or PPGP degradation products (i.e., phosphate, ammonium, and corresponding amino acids) are applied for cell culture using inorganic phosphate (Pi) ion as control. Thus, the influences from substrate surface and degradation products can be identified separately. The results reveal that both the phosphorus‐containing surface of PAGP and PPGP films and their degradation products play significant roles in regulating cell behaviors. In comparison with PAGP, PPGP seems able to provide relatively stable phosphorus‐containing surface to strengthen the cell‐scaffold interaction because of its slower degradation rate and higher Young's modulus, leading to greater promotion in osteogenic differentiation via contact effect. 相似文献
82.
Low-temperature preparation of F-doped TiO2 film and its photocatalytic activity under solar light 总被引:2,自引:0,他引:2
A novel and simple method for preparing F-doped anatase TiO2 (defined as FTO) film with high photocatalytic activity was developed using titanium-n-butoxide and NH4F as TiO2 and fluorine precursors under mild condition, i.e. low temperature (lower than 373 K) and ambient pressure. The prepared samples were characterized by XRD, SEM, X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectrum (DRS), photoluminescence spectrum (PL) and TG-DSC analysis. The photocatalytic activity was evaluated by decomposing X-3B under artificial solar light. The results showed that the crystallinity of TiO2 was improved by F-doping. F− ions can prevent the grain growth, and the transformation of anatase to rutile phase was also inhibited. The doped fluorine atoms existed in two chemical forms, and the ones incorporated into TiO2 lattice might take a positive role in photocatalysis. Compared with surface fluorination samples, FTO film exhibited better photocatalytic activity. The high photocatalytic activity of FTO may due to extrinsic absorption through the creation of oxygen vacancies rather than the excitation of the intrinsic absorption band of bulk TiO2. Furthermore, the FTO can be recycled with little photocatalytic activity depression. Without any further treatment besides rinsing, after 6 recycle utilization, the photocatalytic activity of FTO film was still higher than 79%. 相似文献
83.
Low-temperature preparation of anatase titania-coated magnetite 总被引:1,自引:0,他引:1
Jingjing Xu Yanhui Ao Degang Fu Chunwei Yuan 《Journal of Physics and Chemistry of Solids》2008,69(8):1980-1984
A composite photocatalyst with an anatase titania shell and a magnetite core was prepared in a novel way at low temperature (75 °C at most) by coating photoactive titanium dioxide onto a magnetic Fe3O4 core. The photocatalytic activity of the prepared photocatalyst was evaluated by the degradation of model contaminated water of phenol and compared to single-phase titania (either Degussa P25 or prepared titania without magnetic Fe3O4). The results showed that the photoactivity was slightly depressed. Then, a remarkable improvement in photoactivity was achieved by modifying the photocatalyst with a SiO2 layer between the Fe3O4 core and TiO2 shell. The repetitive using of the modified photocatalyst was also investigated, and experimental results illustrated that the photocatalytic-degraded ratio of phenol was still higher than 80% after six cycles. 相似文献
84.
Min‐Min Xu Ya‐Xian Yuan Jian‐Lin Yao San‐Yang Han Mei Wang Ren‐Ao Gu 《Journal of Raman spectroscopy : JRS》2011,42(3):324-331
The adsorption of 2‐amino‐5‐cyanopyridine (2‐ACP) was investigated in solution at different pH values by i n situ surface‐enhanced Raman scattering (SERS) spectroscopy combined with the electrochemical method. The assignments of the main bands were first performed on the basis of the spectral features of similar compounds and with the help of density functional theory calculations. The results revealed that the adsorption and the interfacial structure of 2‐ACP on the Au electrode depended on the applied potential and the pH values of the solution. In the natural solution, 2‐ACP was adsorbed on the surface with a vertical orientation by the CN group from − 0.4 to − 1.0 V, whereas in the − 0.4 to 0.8 V range, the N atom of the pyridine ring was bound to the surface. A transition region for the reorientation of the two adsorption modes was observed from − 0.8 to − 0.4 V. A flat configuration was preferred at an extremely negative potential. A similar surface adsorption behavior was observed in the alkali environment, while the Stark effect slope decreased because of the adsorption of OH−. Due to the protonation of N atom in the acidic solution, the potential region for the coexistence of two configurations ranged from − 0.4 to 0.2 V. Additionally, a similar adsorption configuration was proposed on the Au colloids at various pH values. The results revealed that the adsorption behavior became more complex on colloidal surfaces than that on a rigid electrode surface. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
85.
Xuejiao Hu Tiancheng Li Yidan Tang Yirong Wang Dr. Ao Wang Dr. Gengtao Fu Prof. Xiaodong Li Prof. Yawen Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7561-7568
The development of high-efficiency electrocatalysts with low costs for the oxygen evolution reaction (OER) is essential, but remains challenging. Herein, a new synthetic process is proposed to prepare Ni3S4 particles embedded in N,P-codoped honeycomb porous carbon aerogels (Ni3S4/N,P-HPC) through a hydrogel approach. The preparation of Ni3S4/N,P-HPC begins with the sol–gel polymerization of tripolyphosphate, chitosan, and guanidine polymer that contains metal-binding sites, allowing for the uniform incorporation of Ni ions into the gel matrix, freeze-drying, and subsequent carbonization under an inert atmosphere. This synthesis resolves difficulties in synthesizing the pure Ni3S4 phase caused by the instability of Ni3S4 at high temperature, while affording good control of the porous structure and N,P-doping of carbon aerogels. The synergy between the structural advantages of N,P-carbon aerogels (such as easily accessible active sites, high specific surface area, and excellent electron transport) and the intrinsic electrochemical properties of Ni3S4 result in the outstanding OER performance of Ni3S4/N,P-HPC, with overpotentials as low as 0.37 V at 10 mA cm−2. The work outlined herein offers a simple and effective method for the development of carbon-based electrocatalysts for renewable energy conversion. 相似文献
86.
Yanping Guan Bilian Li Wei Wei Siyi Wang Vivian‐min Yuen Yao Liu Zheng Ao Shan Zhou Hang Tian Min Huang Xingrong Song Guoping Zhong 《Biomedical chromatography : BMC》2019,33(12)
Dexmedetomidine is an important sedative agent administered as premedication to achieve procedural sedation in children. To describe the correlation between the genetic state and the concentration of dexmedetomidine, it is necessary to develop a specific, time‐saving and economical method for detection of dexmedetomidine in plasma samples. In this work, an ultra‐high‐performance liquid chromatography (UHPLC)–tandem mass spectrometry method has been established and validated for detection of dexmedetomidine in plasma from pediatric population. After a simple liquid–liquid extraction with an organic solution, the analytes were separated on an ACQUITY BEH C18 column (2.1 mm × 50 mm, 1.7 μm particle size) by gradient elution with the mobile phase of acetonitrile and 1‰ aqueous formic acid (flow rate 0.3 mL min?1). Mass spectrometry measurements were performed under the positive selected reaction monitoring and the mass transitions monitored were m/z 201.3 → 95.1, 204.2 → 98.0 for dexmedetomidine and deuterated medetomidine (internal standard), respectively. Validation of the method based on China Food and Drug Administration guidelines showed acceptable selectivity. The UHPLC method employed a stable isotope‐labeled internal standard, showed good specificity and was successfully used to detect dexmedetomidine in plasma samples from 260 pediatric patients. A subsequent application of this method to a pharmacogenetic study was also described. Importantly, this is the first study to report the correlation between CYP2A6 rs835309 activity and concentration of dexmedetomidine. 相似文献
87.
Wei Shi Feng Tang Jiwei Ao Qun Yu Junjie Liu Yubo Tang Bofeng Jiang Xuelian Ren Prof. He Huang Prof. Weibo Yang Prof. Wei Huang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20112-20116
Strain-promoted azide–alkyne cycloaddition using dibenzoazacyclooctyne (DBCO) is widely applied in copper-free bioorthogonal reactions. Reported here is the efficient acid-promoted rearrangement and silver-catalyzed amidation of DBCO, which alters its click reactivity robustly. In the switched click reaction, DBCO, as a caged acylation reagent, enables rapid peptide/protein modification after decaging facilitated by silver catalysts, rendering site-specific conjugation of an IgG antibody by a Fc-targeting peptide. 相似文献
88.
89.
Koser's reagent is found to be effective in the oxidative double dehydrogenation of various carbocyclic β-dicarbonyl compounds,which constitutes the first example on dehydrogenation reactivity of hypervalent iodine(Ⅲ) reagents for carbocyclic carbonyl compounds. DFT calculations reveal that the rate-determining step is the electrophilic addition of PhI+OH onto enolate of monodehydrogenated product. 相似文献
90.
Ao‐kai Zhang Jun Ling Kewen Li Guo‐dong Fu Tasuku Nakajima Takayuki Nonoyama Takayuki Kurokawa Jian Ping Gong 《Journal of Polymer Science.Polymer Physics》2016,54(13):1227-1236
In this study, controlled amount of dangling ends is introduced to the two series of poly(ethylene glycol)‐based hydrogel networks with three and four crosslinking functionality by using click chemistry. The structure of the gels with regulated defect percentage is confirmed by comparing the results of low‐field NMR characterization and Monte Carlo simulation. The mechanical properties of these gels were characterized by tensile stress–strain behaviors of the gels, and the results are analyzed by Gent model and Mooney–Rivlin model. The shear modulus of the swollen gels is found to be dependent on the functionality of the network, and decreases with the defect percentage. Furthermore, the value of shear modulus well obeys the Phantom model for all the gels with varied percentage of the defects. The maximum extension ratio, obtained from the fitting of Gent model, is also found to be dependent on the functionality of the network, and does not change with the defect percentage, except at very high defect percentage. The value of the maximum extension ratio is between that predicted from Phantom model and the Affine model. This indicates that at the large deformation, the fluctuation of the crosslinking points is suppressed for some extend but still exists. Polymer volume fractions at various defect percentages obtained from prediction of Flory–Rehner model are found to be in well agreement with the swelling experiment. All these results indicate that click chemistry is a powerful method to regulate the network structure and mechanical properties of the gels. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1227–1236 相似文献