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881.
Yan Taihong Zhen Weifang Ye Guoan Zhang Yu Xian Liang Di Ying Bian Xiaoyan 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):293-299
Dihydroxyurea (DHU) was synthesized using tri-associated solid phosgene [bis(trichloromethyl) carbonate] dissolved in dioxane and hydroxylamine hydrochloride dissolved in potassium acetate solution.
The reduction of Pu(IV) by DHU was investigated using UV-Vis spectrophotometry. The reduction back-extraction behavior of
Pu(IV) in 30% tri-butyl phosphate/kerosene was firstly investigated under conditions of various temperature, various DHU and
HNO3 concentrations and various phase contact times. The results showed that Pu(IV) in the organic phase can be stripped rapidly
to the aqueous phase by DHU. Simulating the 1B contactor of the PUREX process using a 0.1 M DHU in 0.36M nitric acid solution
as the stripping agent, the separation factors of uranium/plutonium can reach 2.1·104. This indicates that DHU is a promising salt free agent for uranium/plutonium separation. 相似文献
882.
The objective of this study was to evaluate the performance of a photocatalysis/H2O2/metal membrane hybrid system in the degradation of humic acid. A metal membrane of nominal pore size 0.5 μm was used in the
experiment for separation of TiO2 particles. Hydrogen peroxide was tested as an oxidant. The efficiency of removal of CODCr and color increased rapidly for initial hydrogen peroxide concentrations up to 50 mg L−1. The efficiency of removal of CODCr and color by 50 mg L−1 initial hydrogen peroxide concentration was approximately 95 and 98%, respectively. However, addition of hydrogen peroxide
over 50 mg L−1 inhibited the efficiency of the system. Addition of hydrogen peroxide to a UV/TiO2 system enhanced efficiency of removal of CODCr and color compared with no addition of hydrogen peroxide. This may be ascribed to capture electrons ejected from TiO2 and to the production of OH radicals. Application of the metal membrane in the UV/TiO2/H2O2 system enhanced the efficiency of removal of CODCr and color because of adsorption by the metal membrane surface and the production of OH radicals. By application of a metal
membrane with a nominal pore size of 0.5 μm, TiO2 particles were effectively separated from the treated water by metal membrane rejection. The photocatalytic metal membrane
had much less resistance than the humic acid, TiO2, and humic acid/TiO2 because of the degradation of humic acid by the photocatalytic reaction. 相似文献
883.
The optimal performance of heat-driven binary separation processes with linear phenomenological heat transfer law(q∝△(T-1)) is analyzed by taking the processes as heat engines which work between high-and low-temperature reservoirs and produce enthalpy and energy flows out of the system,and the temperatures of the heat reservoirs are assumed to be time-and space-variables.A numerical method is employed to solve convex optimization problem and Lagrangian function is employed to solve the average optimal contr... 相似文献
884.
Aiju Zhang Zhihong Li Zicheng Li Yumei Zhu 《Journal of Sol-Gel Science and Technology》2009,49(1):6-11
SiO2–Al2O3–Na2O glass coated cubic boron nitride (cBN) abrasive particles were prepared by sol–gel technique. The results indicated that
SiO2–Al2O3–Na2O glass was excellent material for oxidation protection of cBN abrasive grains because coefficient of thermal expansion of
this glass closely matched that of cBN materials. The single particle compressive strength and impact toughness of this glass
coated cBN abrasive particles were significantly increased. For the application of glass coated cBN abrasives to vitrified
grinding wheels, it was evident that the glass coating provided high bonding strength between cBN abrasive grains and vitrified
bond system. 相似文献
885.
886.
Yiping Guo Daisuke Akai Kazuaki Sawada Makoto Ishida Mingyuan Gu 《Journal of Sol-Gel Science and Technology》2009,49(1):66-70
Highly (110)-oriented Ba0.65Sr0.35TiO3 films were deposited on Pt/LaNiO3/SiO2/Si substrates by a sol–gel method. It was found that the (110)-preferred Pt film was very effective for growing (110)-oriented
ferroelectric films with perovskite structure. The as-grown Ba0.65Sr0.35TiO3 films showed good dielectric properties with dielectric constant and loss tangent tan δ = 0.026. Excellent dielectric tunability was also achieved in the (110)-oriented films. With applying
an electric field of 230 kV/cm at 100 kHz, the dielectric tunability and the figure of merit can reach up to 63.4% and 16,
respectively. These results indicate that the highly (110)-oriented Ba0.65Sr0.35TiO3 film is a promising candidate for the applications in microwave tunable devices. 相似文献
887.
Silica films with honeycomb-like structure were successfully obtained by emulsion method. Emulsion films prepared by the Dip-Withdrawing
method were dried at 180 °C for 2 h and sintered at 500 °C, the films turned from superhydrophilic to superhydrophobic after
being modified by octyltrimethoxysilane (OTMS) to form a self-assembled monolayer (SAM) with low surface energy. The surface
structures and the thickness of the silica emulsion films were observed by scanning electron microscopy (SEM), and the results
showed that the emulsion method had a similar effect to the phase separation one on producing the honeycomb-like structure
that highly influenced the wettability of solid surface. 相似文献
888.
de Lima CJ Ribeiro EJ Sérvulo EF Resende MM Cardoso VL 《Applied biochemistry and biotechnology》2009,152(1):156-168
Pseudomonas aeruginosa PACL strain, isolated from oil-contaminated soil taken from a lagoon, was used to investigate the efficiency and magnitude
of biosurfactant production, using different waste frying soybean oils, by submerged fermentation in stirred tank reactors
of 6 and 10 l capacities. A complete factorial experimental design was used, with the goal of optimizing the aeration rate
(0.5, 1.0, and 1.5 vvm) and agitation speed (300, 550, and 800 rpm). Aeration was identified as the primary variable affecting
the process, with a maximum rhamnose concentration occurring at an aeration rate of 0.5 vvm. At optimum levels, a maximum
rhamnose concentration of 3.3 g/l, an emulsification index of 100%, and a minimum surface tension of 26.0 dynes/cm were achieved.
Under these conditions, the biosurfactant production derived from using a mixture of waste frying soybean oil (WFSO) as a
carbon source was compared to production when non-used soybean oil (NUSO), or waste soybean oils used to fry specific foods,
were used. NUSO produced the highest level of rhamnolipids, although the waste soybean oils also resulted in biosurfactant
production of 75–90% of the maximum value. Under ideal conditions, the kinetic behavior and the modeling of the rhamnose production,
nutrient consumption, and cellular growth were established. The resulting model predicted data points that corresponded well
to the empirical information. 相似文献
889.
Eric B. Kalman Olivier Sudre Ivan Vlassiouk Zuzanna S. Siwy 《Analytical and bioanalytical chemistry》2009,394(2):413-419
Control of ionic transport through nanoporous systems is a topic of scientific interest for the ability to create new devices
that are applicable for ions and molecules in water solutions. We show the preparation of an ionic transistor based on single
conical nanopores in polymer films with an insulated gold thin film “gate.” By changing the electric potential applied to
the “gate,” the current through the device can be changed from the rectifying behavior of a typical conical nanopore to the
almost linear behavior seen in cylindrical nanopores. The mechanism for this change in transport behavior is thought to be
the enhancement of concentration polarization induced by the gate.
Figure
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
890.
Dongfang Zhang 《Journal of mathematical chemistry》2009,46(2):576-585
The electronic transitions and excited-state fragmentation of hydrogen iodide have been studied within the A-band continuum.
The extinction intensity for the excitations from the ground to the low-lying electronic states are derived by performing
the wave packet simulations of nuclear dynamics in this study. The quantum yields of the spin-excited I* product at the different photon energies are determined as well. The results suggest that the possibility of intersystem
crossing can be neglected. Employing the time-dependent density functional theory (TDDFT), the four highest occupied and the
two lowest unoccupied orbitals of hydrogen iodide have been analyzed, and the transition to the state is found to be most probable in the first absorption band. 相似文献