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991.
Chu H Xiong Z Wu G Guo J He T Chen P 《Dalton transactions (Cambridge, England : 2003)》2010,39(44):10585-10587
Ca(BH(4))(2)-LiNH(2) combined system is shown to release hydrogen at much lower temperature compared to the pure Ca(BH(4))(2). The improved dehydrogenation in this system can be ascribed to a combination reaction between [BH(4)] and [NH(2)] based on the reaction mechanism of positive H and negative H. 相似文献
992.
A new labdanic norditerpene and six known labdanic diterpenes were isolated from the petroleum ether extract of the needles of Pinus sylvestris. By spectroscopic methods, the isolated compounds were determined as 15-norpinifolic acid (1), pinifolic acid (2), 4-eplimbricataloic acid (3), monomethyl pinifolate (4), 18α-acetoxylabd-8(17)-en-15-oic acid (5), 2-pentenoic acid (6) and 3β-hydroxy-8(17),E-13-labdadien-15-oic acid (7), respectively. Compound 1 showed significant anti-tumour activity. 相似文献
993.
Zengyun Hu Zhidong Teng Haijun Jiang 《Nonlinear Analysis: Real World Applications》2012,13(5):2017-2033
In this paper, the dynamical behaviors of a class of discrete-time SIRS epidemic models are discussed. The conditions for the existence and local stability of the disease-free equilibrium and endemic equilibrium are obtained. The numerical simulations not only illustrate the validity of our results, but also exhibit more complex dynamical behaviors, such as flip bifurcation, Hopf bifurcation and chaos phenomenon. These results reveal far richer dynamical behaviors of the discrete epidemic model compared with the continuous epidemic models. 相似文献
994.
Duliang He Mindong Chen Fei Teng Guiqing Li Huaxia Shi Jun Wang Mengjiao Xu Tianyun Lu Xuequn Ji Yingjie Lv Yongfa Zhu 《Superlattices and Microstructures》2012
CdS nanoparticles were in situ deposited on TiO2 nanosheets and nanorods under hydrothermal conditions, respectively. The effect of CdS–TiO2 interface structure on hydrogen production activity was mainly investigated under visible light irradiation. The results showed that the TiO2 nanosheet-based CdS/TiO2 showed a higher activity and a higher cyclability than the nanorod-based sample due to the stronger interaction of CdS with the (0 0 1) facets of TiO2 than with the (1 0 1) facets. It was proposed that the strong interaction between CdS nanoparticles and TiO2 nanosheets effectively refrains the recombination of electrons and holes. 相似文献
995.
A novel Nafion-sulfonated diphenyldimethoxysilane (N-sDDS) composite membrane is prepared and employed in vanadium redox flow
battery (VRB). Ion exchange capacity, proton conductivity, water transport behavior, and the cell performances are characterized.
Fourier transform-infrared and X-ray diffraction analysis indicate that the sulfonated diphenyldimethoxysilane (sDDS) particles
are successfully introduced into the Nafion matrix. In VRB single cell test, the VRB with N-sDDS membrane exhibits nearly
the same coulombic efficiency as the unmodified Nafion membrane, but higher voltage efficiency than that of the VRB with unmodified
Nafion membrane. The VRB with N-sDDS composite membrane keeps a stable performance after 60 times charge–discharge test. In
the self-discharge test, the VRB with the N-sDDS membrane presented a lower self-discharge rate than that of the VRB with
Nafion membrane. All results show that the addition of s-DDS is a simple and efficient way to improve the conductivity of
Nafion, and the composite membrane shows good potential use for VRB. 相似文献
996.
Spaulding UK Christensen CJ Crisp RJ Vaughn MB Trauscht RC Gardner JR Thatcher SA Clemens KM Teng DH Bird A Ota IM Hadfield T Ryan V Brunelle SL 《Journal of AOAC International》2012,95(3):860-891
The RAZOR EX Anthrax Air Detection System, developed by Idaho Technology, Inc. (ITI), is a qualitative method for the detection of Bacillus anthracis spores collected by air collection devices. This system comprises a DNA extraction kit, a freeze-dried PCR reagent pouch, and the RAZOR EX real-time PCR instrument. Each pouch contains three assays, which distinguish potentially virulent B. anthracis from avirulent B. anthracis and other Bacillus species. These assays target the pXO1 and pXO2 plasmids and chromosomal DNA. When all targets are detected, the instrument makes an "anthrax detected" call, meaning that virulence genes of the anthrax bacillus are present. This report describes results from AOAC Method Developer (MD) and Independent Laboratory Validation (ILV) studies, which include matrix, inclusivity/exclusivity, environmental interference, upper and lower LOD of DNA, robustness, product consistency and stability, and instrument variation testing. In the MD studies, the system met the acceptance criteria for sensitivity and specificity, and the performance was consistent, stable, and robust for all components of the system. For the matrix study, the acceptance criteria of 95/96 expected calls was met for three of four matrixes, clean dry filters being the exception. Ninety-four of the 96 clean dry filter samples tested gave the expected calls. The nucleic acid limit of detection was 5-fold lower than AOAC's acceptable minimum detection limit. The system demonstrated no tendency for false positives when tested with Bacillus cereus. Environmental substances did not inhibit accurate detection of B. anthracis. The ILV studies yielded similar results for the matrix and inclusivity/exclusivity studies. The ILV environmental interference study included environmental substances and environmental organisms. Subsoil at a high concentration was found to negatively interfere with the pXO1 reaction. No interference was observed from the environmental organisms. The nucleic acid LOD, however, was 10 times higher (1 pg/reaction, equivalent to about 200 spores) than that found in the MD study. These results indicate that the RAZOR System is a sensitive and specific system that accurately identifies B. anthracis in aerosol matrixes and in the presence of interfering substances, and that the method can be performed by an independent laboratory and achieve similar results. 相似文献
997.
Yan Zhang Teng Qiu Qi Hao Fan Kong Jinlei Gao Paul K. Chu 《Journal of luminescence》2012,132(10):2586-2589
We demonstrate a convenient nanotechnique to modulate Si–Ag “wire-cap” nanostructures for metal-enhanced fluorescence by self-selective electroless plating on Si. Optimized coupling between Ag caps and organic emitter can be achieved by altering the bending degree of the Si nanowires resulting in significantly enhanced local electric field intensity. The enhanced photoluminescence from the organic emitter coupled Si–Ag “wire-cap” nanostructures derives from the excitation of localized surface plasmons between the Ag nanocaps and also the energy transfer effect in the surface plasmon resonant coupling between the organic emitter and Ag caps. Our technique has potential applications in biochemical sensors and light emitters. 相似文献
998.
结合EAM镶嵌原子作用势, 通过经典的分子动力学模拟研究了不同截面尺寸Al纳米线在两种冷却速率下的凝固行为, 并采用键对分析技术探讨了相变过程中原子团簇的演化情况. 结果表明:Al纳米线的最终结构不仅与冷却速率有关, 还呈现出明显的尺寸效应. 在较快的冷却速率下, 五种截面尺寸的Al纳米线均得到了多壳螺旋结构; 而当冷却速率降低以后, 除了N3纳米线发生了断裂以外, 其余纳米线的结构随着截面尺寸的增加, 逐渐从多壳螺旋结构经由类-六边形多壳结构最终过渡到稳定的晶态结构. 相似文献
999.
实验提取了弱散射体产生的菲涅耳极深区的散斑场.发现当散射距离一定时,弱散射体光场的相位分布特征随散射体的粗糙度的变化而变化;对于某一弱散射体,相位分布特征随散射距离的变化而变化;当弱散射体的粗糙度大到一定程度时,才产生相位涡旋现象;散射体表面上存在相位涡旋;弱散射体产生的相位涡旋的密度随散射屏粗糙度的增大而增大,还随散射距离的增大而增大.研究结果对于认识弱散射体的相位及相位涡旋分布特征随粗糙度和散射距离的演化具有重要意义,而且对于认识散斑场随散射距离的演化有一定的帮助. 相似文献
1000.