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991.
Mei-Li You Sheng-Yi Weng Min-Siou Liao Can-Yong Jhu Yun-Ting Tsai Quentin Lineberry Chi-Min Shu 《Journal of Thermal Analysis and Calorimetry》2014,116(3):1453-1459
Isoprene monomer (IPM) is a colorless, volatile liquid obtained from petroleum or coal tar that occurs naturally in many process plants. It is used chiefly to make synthetic rubber. Our study used calorimetric approaches to conduct thermal analysis and hazard assessment of aluminum oxide (Al2O3) and IPM relevant studies. Differential scanning calorimetry, thermal activity monitor III, thermogravimetry, and vent sizing package 2 were used to discuss thermal instability reaction of Al2O3, which adsorbed IPM, and find every possible reason for cases of fire to prevent any future recurrence of the package store and transport related hazards. By means of calorimetric analysis technology, we can observe thermal decomposition or mass loss for different adsorbed concentrations of IPM and Al2O3 to discuss the related thermal stability parameters, such as exothermic onset temperature (T 0), heat of decomposition (ΔH d), self-accelerating exothermic rate (dT dt ?1), pressure rise rate, and maximum reaction temperature (T max). Then, we can understand the potential hazard factors that contribute to disasters related to processing, transport, and storage of security controls and reaction process design. 相似文献
992.
Yan Shao Dan‐Wei Ou‐Yang Wen Gao Liang Cheng Xiao‐Xiang Weng De‐Yun Kong 《Helvetica chimica acta》2014,97(7):992-998
Three new pentacyclic triterpenoids, named centellasaponin I ( 1 ), centellasaponin J ( 2 ), and centellasaponin E ( 3 ), together with three known compounds, were isolated from the whole plants of Centella asiatica. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D‐ and 2D‐NMR and HR‐MS experiments, and by comparison with literature data. 相似文献
993.
Elastic and Wearable Wire‐Shaped Lithium‐Ion Battery with High Electrochemical Performance
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Jing Ren Ye Zhang Wenyu Bai Xuli Chen Zhitao Zhang Xin Fang Wei Weng Dr. Yonggang Wang Prof. Huisheng Peng 《Angewandte Chemie (International ed. in English)》2014,53(30):7864-7869
A stretchable wire‐shaped lithium‐ion battery is produced from two aligned multi‐walled carbon nanotube/lithium oxide composite yarns as the anode and cathode without extra current collectors and binders. The two composite yarns can be well paired to obtain a safe battery with superior electrochemical properties, such as energy densities of 27 Wh kg?1 or 17.7 mWh cm?3 and power densities of 880 W kg?1 or 0.56 W cm?3, which are an order of magnitude higher than the densities reported for lithium thin‐film batteries. These wire‐shaped batteries are flexible and light, and 97 % of their capacity was maintained after 1000 bending cycles. They are also very elastic as they are based on a modified spring structure, and 84 % of the capacity was maintained after stretching for 200 cycles at a strain of 100 %. Furthermore, these novel wire‐shaped batteries have been woven into lightweight, flexible, and stretchable battery textiles, which reveals possible large‐scale applications. 相似文献
994.
Flexible and Stretchable Lithium‐Ion Batteries and Supercapacitors Based on Electrically Conducting Carbon Nanotube Fiber Springs
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Ye Zhang Wenyu Bai Dr. Xunliang Cheng Jing Ren Dr. Wei Weng Peining Chen Xin Fang Zhitao Zhang Prof. Huisheng Peng 《Angewandte Chemie (International ed. in English)》2014,53(52):14564-14568
The construction of lightweight, flexible and stretchable power systems for modern electronic devices without using elastic polymer substrates is critical but remains challenging. We have developed a new and general strategy to produce both freestanding, stretchable, and flexible supercapacitors and lithium‐ion batteries with remarkable electrochemical properties by designing novel carbon nanotube fiber springs as electrodes. These springlike electrodes can be stretched by over 300 %. In addition, the supercapacitors and lithium‐ion batteries have a flexible fiber shape that enables promising applications in electronic textiles. 相似文献
995.
Radhiya Al-Hashemi Nasser Safari Vahid Amani Saeid Amani Seik Weng Ng 《Journal of the Iranian Chemical Society》2014,11(2):341-349
Two new copper complexes [Cu(Hdpa)2(en)] (1) and [{Cu2(μ-na)4(CH3OH)2}·2CH3OH] (2) (where en is ethylene diamine, Hdpa is 2′-carboxy-[1,10-biphenyl]-2-carboxylate anion and na is 1-naphtalenecarboxylate) have been synthesized and their crystal structures were determined by X-ray crystallography. Complex 1 was prepared from the reaction of Cu(NO3)2·3H2O with ethylene diamine and 2,2′-biphenyldicarboxylic acid in a mixture of water and methanol and complex 2 was prepared from the reaction of CuSO4·5H2O with 1-naphtalenecarboxylic acid in methanol. The two complexes were characterized by IR, UV–vis, luminescence and elemental analysis. Moreover, complex 2 was characterized by EPR spectroscopy and thermogravimetric analysis. Complex 1 is a monomer and complex 2 is a dimer with a paddle-wheel structure; both structures are without precedent in the literature. 相似文献
996.
Zouaoui Setifi Fouzia Lehchili Fatima Setifi Adel Beghidja Seik Weng Ng Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(3):338-341
In the title salt, C14H18N22+·2C9H5N4O−, the 1,1′‐diethyl‐4,4′‐bipyridine‐1,1′‐diium dication lies across a centre of inversion in the space group P21/c. In the 1,1,3,3‐tetracyano‐2‐ethoxypropenide anion, the two independent –C(CN)2 units are rotated, in conrotatory fashion, out of the plane of the central propenide unit, making dihedral angles with the central unit of 16.0 (2) and 23.0 (2)°. The ionic components are linked by C—H...N hydrogen bonds to form a complex sheet structure, within which each cation acts as a sixfold donor of hydrogen bonds and each anion acts as a threefold acceptor of hydrogen bonds. 相似文献
997.
Zhifeng Weng Shuying Zhai Xinlong Feng 《Numerical Methods for Partial Differential Equations》2019,35(6):1949-1970
In this paper, we consider a second‐order fast explicit operator splitting method for the viscous Cahn‐Hilliard equation, which includes a viscosity term αΔut (α ∈ (0, 1)) described the influences of internal micro‐forces. The choice α = 0 corresponds to the classical Cahn‐Hilliard equation whilst the choice α = 1 recovers the nonlocal Allen‐Cahn equation. The fundamental idea of our method is to split the original problem into linear and nonlinear parts. The linear subproblem is numerically solved using a pseudo‐spectral method, and thus an ordinary differential equation is obtained. The nonlinear one is solved via TVD‐RK method. The stability and convergence are discussed in L2‐norm. Numerical experiments are performed to validate the accuracy and efficiency of the proposed method. Besides, a detailed comparison is made for the dynamics and the coarsening process of the metastable pattern for various values of α. Moreover, energy degradation and mass conservation are also verified. 相似文献
998.
Basis risk arises in a number of financial and insurance risk management problems when the hedging assets do not perfectly match the underlying asset in a hedging program. Notable examples in insurance include the hedging for longevity risks, weather index–based insurance products, variable annuities, etc. In the presence of basis risk, a perfect hedging is impossible, and in this paper, we adopt a mean‐variance criterion to strike a balance between the expected hedging error and its variability. Under a time‐dependent diffusion model setup, explicit optimal solutions are derived for the hedging target being either a European option or a forward contract. The solutions are obtained by a delicate application of the linear quadratic control theory, the method of backward stochastic differential equation, and Malliavin calculus. A numerical example is presented to illustrate our theoretical results and their interesting implications. 相似文献
999.
Multifunctional TiO2‐Based Particles: The Effect of Fluorination Degree and Liquid Surface Tension on Wetting Behavior
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Yuekun Lai Huanfu Zhou Zheng Zhang Yuxin Tang Jeffrey Weng Chye Ho Jianying Huang Qiuling Tay Keqin Zhang Zhong Chen Bernard P. Binks 《Particle & Particle Systems Characterization》2015,32(3):355-363
A systematic investigation into the influence of the degree of fluorination on the static and dynamic wetting behavior of TiO2‐based nanobelt (TNB) particles with various liquids is described. The effect of the degree of fluorination and the surface tension of the liquid on the occurrence and stability of liquid marbles, foams or dispersions are studied and the wetting behavior and arrangement of particles at the air–liquid surface are observed. Using contact angle (θ) measurements, the relation between the type of particle‐stabilized material and θ is established. For liquids of relatively high tension like water or formamide which do not wet the fluorinated particles, a powder‐like material (marble) is formed. For polar oils of intermediate tension (35–50 mN m?1), which partially wet the fluorinated particles, stable air‐in‐oil foams can be prepared in which particles form a close‐packed layer enveloping air bubbles. Liquids of relatively low tension, e.g., ethanol or polydimethylsiloxane, wet the particles forming a uniform dispersion and partial sedimentation. By contrast, the as‐prepared hydrophilic TNB particles are rapidly wetted by all the liquids as expected due to their high surface energy. The stable cross‐stacked TNB particles with fluoroalkylsilane (FAS) modification could be a versatile platform in a wide range of applications, especially for fluidic devices (e.g., biofluids, gas sensing, and lab‐on‐a‐chip devices). In a proof‐of‐concept study, the oil–water separation performance of fabrics with chemically stable TNB/FAS coating and the liquid isolation by a TNB/FAS shell for highly sensitive gas sensing or reagent assays are investigated. 相似文献
1000.
The thermal degradation behavior of nylon-6 (PA6) and PA6/attapulgite (ATP) nanocomposites was investigated by thermogravimetric analysis under non-isothermal conditions at various heating rates in nitrogen. It is suggested that during thermal degradation, ATP, as a protective barrier, can slow down degradation of polymer, but the catalytic effects of structural water and hydroxyl groups may accelerate the degradation of PA6. The combination of these two effects determined the final thermal stability of nanocomposites. The apparent activation energies of the samples were evaluated by the Kissinger and Flynn–Wall–Ozawa methods. The results showed that the presence of ATP adversely affected the thermal stability of PA6. The degradation activation energies of PA6/ATP nanocomposites decreased monotonically with increase in ATP content; thus, it is suggested that the ATP has a disadvantageous effect on the thermal stability of PA6. 相似文献