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以MMA为起始原料经转变为GMA,再与双酚-S反应合成了一种新的含有砜基的交联剂BisS-GMA。这种双酚-S型交联剂与MMA可以顺利地用紫外光或BPO-胺体系引发聚合。新的双酚-S型交联剂BisS-GMA与双酚-A型交联剂Bis-GMA相比,具有活性高与粘结强度高两个显著优点。它还可以和二氧化硅填料混合组成复合树脂,经光引发或BPO-DHET体系引发聚合,得到的复合树脂其物性已达到国外同类产品的水平。DHET作为促进剂要比DMT性能好,前者配制的交联剂液体组份贮存稳定性好,经半年后而不“失活”,后者配制的液体组份则在较短的时间内“失活”。 相似文献
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The geometric and electronic structures of FeS(2) (100) surface have been studied by a quantum-mechanical calculation using a total-energy pseudopotential code, CASTEP. The (100) surface is very stable and does not give any significant geometric relaxation. The electronic structure of FeS(2) (100) surface is characterized by the appearance of new native surface states in the bulk band gap, which correspond to antibonding mixed Fea-Ssp(3) states. These surface states play an important role as mediators of electron transfer on both anodic and cathodic sites in the incipient oxidation of pyrite. Moreover, the (100) surface has small band gaps and shows some metallic character. It is predicted that the rate of cathodic reductive reaction of O(2) in the incipient oxidation of pyrite is much faster than previously considered. The transport of electrons from the anodic sites to the cathodic sites on the (100) surface is faster and hole injection of anodic sites is not the rate-determining step. So we can deduce that the rate-determining step of incipient oxidation for pyrite consists of both electron transfer of pyrite/aqueous O(2) interface and the splitting of H(2)O. 相似文献
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Interval analysis method and convex models for impulsive response of structures with uncertain-but-bounded external loads 总被引:1,自引:1,他引:0
Two non-probabilistic, set-theoretical methods for determining the maximum and minimum impulsive responses of structures to uncertain-but-bounded impulses are presented. They are, respectively, based on the theories of interval mathematics and convex models. The uncertain-but-bounded impulses are assumed to be a convex set, hyper-rectangle or ellipsoid. For the two non-probabilistic methods, less prior information is required about the uncertain nature of impulses than the probabilistic model. Comparisons between the interval analysis method and the convex model, which are developed as an anti-optimization problem of finding the least favorable impulsive response and the most favorable impulsive response, are made through mathematical analyses and numerical calculations. The results of this study indicate that under the condition of the interval vector being determined from an ellipsoid containing the uncertain impulses, the width of the impulsive responses predicted by the interval analysis
method is larger than that by the convex model; under the condition of the ellipsoid being determined from an interval vector containing the uncertain impulses, the width of the interval impulsive responses obtained by the interval analysis method is smaller than that by the convex model.The project supported by the National Outstanding Youth Science Foundation of China (10425208), the National Natural Science Foundation of China and Institute of Engineering Physics of China (10376002) The English text was polished by Keren Wang. 相似文献
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Zhen-Lin Qiu Dandan Chen Zeying Deng Ke-Shan Chu Yuan-Zhi Tan Jun Zhu 《中国科学:化学(英文版)》2021,(6):1004-1008
Carbon nanohoop,a class of constrained molecular architecture consisting of linked arene units,has attracted considerable interest from both experimental and th... 相似文献
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In this paper,the symplectic perturbation series methodology of the non-conservative linear Hamiltonian system is presented for the structural dynamic response ... 相似文献
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Huaming?YangEmail author Guanzhou?Qiu Xiangchao?Zhang Aidong?Tang Wuguo?Yang 《Journal of nanoparticle research》2004,6(5):539-542
CdO nanoparticles of 43 nm in crystal size were successfully synthesized by the mechanochemical reaction (CdCl2 + Na2CO3) with NaCl as a diluent and subsequent thermal treatment at 700°C for 2 h. The samples were characterized by differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Effect of calcination temperature on the crystal size of CdO nanoparticles was primarily investigated. The apparent activation energy of CdO nanoparticle formation during thermal treatment was calculated to be 12.2 kJ/mol. 相似文献