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81.
82.
Emamectin benzoate, a macrocyclic lactone, can be used in low quantities to control arthropod pests, effectively. However, its poor photostability prevents its further use. To delay its photodegradation, novel acrylate‐type polymeric nanoparticles were synthesized and tested as materials for improving pesticide photostability. N‐acylated emamectin benzoate was synthesized via bonding emamectin benzoate to acrylamide. The resulting pesticide, containing the double bond linkage –C=C–N–, was copolymerized with butyl acrylate and methyl methacrylate by the emulsion polymerization method. The refined polymers were characterized by Fourier transform infrared spectroscopy spectroscopy, and result illustrated the pesticide was conjugated to the polymers. Atomic force microscope and dynamic light scattering analyses were also used for determining the average particle diameters of pesticide–polymer conjugates. Photostability tests showed that the nanoparticles obtained exhibited greatly improved photostability. Additionally, the laboratory toxicity tests demonstrated that the insecticidal effects of the novel emamectin benzoate formulation were better than those of the control pesticide formulation (emamectin benzoate EC). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
83.
Information regarding the metabolism of xenobiotic chemicals plays a central role in regulatory risk assessments. In regulatory programmes where metabolism studies are required, the studies of metabolic pathways are often incomplete and the identification of activated metabolites and important degradation products are limited by analytical methods. Because so many more new chemicals are being produced than can be assessed for potential hazards, setting assessment priorities among the thousands of untested chemicals requires methods for predictive hazard identification which can be derived directly from chemical structure and their likely metabolites. In a series of papers we are sharing our experience in the computerized management of metabolic data and the development of simulators of metabolism for predicting the environmental fate and (eco)toxicity of chemicals. The first paper of the series presents a knowledge-based formalism for the computer simulation of non-intermediary metabolism for untested chemicals, with an emphasis on qualitative and quantitative aspects of modelling metabolism. 相似文献
84.
《Green Chemistry Letters and Reviews》2013,6(1):1-2
Abstract Zinc dust serves as a reducing agent in the presence of ammonium formate and NaOH, and is highly effective for the hydrodebromination of decabromodiphenyl ether to give diphenyl ether and the less brominated diphenyl ethers. 相似文献
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A. Marcilla A. Gómez-Siurana S. Menargues 《Journal of Thermal Analysis and Calorimetry》2007,87(2):519-527
A study of the catalytic degradation of EVA
copolymers under air atmosphere has been carried out using thermogravimety
(TG). Three commercial EVA copolymers and five zeolites and related materials
catalysts have been selected. The degradation process in air atmosphere involves
four main decomposition steps (as observed in TG), being more complex than
the corresponding process in inert atmosphere. The presence of MCM-41, HY
and H-β does not seem to noticeably affect to the overall degradation
temperature, despite the temperature of maximum reaction rate for the second
decomposition step being slightly displaced towards lower temperatures. Contrarily,
the presence of HZSM-5 and HUSY zeolites seems to displace the main stage
of the oxidative degradation process towards higher temperatures. Moreover,
the relative importance of the second and third decomposition step is different
depending on the amount and the nature of the zeolite mixed with the EVA sample.
The results obtained show that the presence of the catalyst also enhances
the formation of the carbonous residue. 相似文献
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Hélène A. Lecomte 《Polymer Degradation and Stability》2008,93(2):498-506
Many types of fire retardants are used in poly(ethylene terephthalate), PET, formulations, and two commercial fire retardants, Ukanol® and Phosgard®, have been shown to improve significantly PET flame-retardancy when used as comonomers. Phosgard incorporates a phosphorus atom within the main chain whereas Ukanol incorporates a phosphorus atom as a pendent substituent. Despite their acknowledged effectiveness, the mode of action of these fire retardants remains unclear, and in this paper we present a comparison of the overall thermal degradation behaviour of PET and Ukanol and Phosgard fire-retarded formulations. DSC and particularly TGA data show that both Ukanol and Phosgard have some stabilising influence on PET degradation, especially under oxidative conditions. TGA and pyrolysis experiments both clearly indicate that neither of the additives acts as a char promoter. Only the Phosgard formulation shows any release of volatile phosphorus species which could act in the gas phase. On the other hand, the most striking feature of the pyrolysis experiments is the macroscopic structure of the chars produced by the fire-retarded formulations, which hints at their fire-retardancy action - an open-cell charred foam was obtained upon charring at 400 °C or 600 °C. This foaming layer between the degrading melt and the flame would lower the amount of fuel available for combustion, and would also limit the feedback of heat to the condensed phase. 相似文献
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