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51.
Javid Hussain Nausheen Bukhari Hidayat Hussain Sajjad Haider Zahid Hassan 《Helvetica chimica acta》2010,93(7):1428-1431
Phlomisamide ( 1 ), a new ceramide, and a new stigmasterol derivative, phlomisteriod ( 2 ), have been isolated from Phlomis cashmeriana. Their structures were elucidated by comprehensive analysis of their 1D‐ (1H‐ and 13C‐NMR) and 2D‐NMR (COSY, HMQC, HMBC), and HR‐EI‐MS data. 相似文献
52.
Palladium and Fe3O4 nanoparticles were deposited on N‐(2‐aminoethyl)acetamide‐functionalized cellulose for use in a catalytic reaction. The catalyst was characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X‐ray diffraction, energy‐dispersive X‐ray analysis and transmission electron microscopy, and applied in the oxidation reaction of ethylbenzene at 100 °C using H2O2. Styrene oxide was obtained as the sole product of the oxidation reaction during 24 h. This reaction has some advantages such as one‐pot transformation of ethylbenzene to styrene oxide, high yield, excellent selectivity and magnetically recoverable catalyst. Also, the recovered catalyst could be used in the oxidation reaction four times without decrease in yield. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
53.
Length‐Scale‐Dependent Phase Transformation of LiFePO4: An In situ and Operando Study Using Micro‐Raman Spectroscopy and XRD 下载免费PDF全文
Dr. N. A. Siddique Amir Salehi Zi Wei Dong Liu Syed D. Sajjad Prof. Fuqiang Liu 《Chemphyschem》2015,16(11):2383-2388
The charge and discharge of lithium ion batteries are often accompanied by electrochemically driven phase‐transformation processes. In this work, two in situ and operando methods, that is, micro‐Raman spectroscopy and X‐ray diffraction (XRD), have been combined to study the phase‐transformation process in LiFePO4 at two distinct length scales, namely, particle‐level scale (~1 μm) and macroscopic scale (~several cm). In situ Raman studies revealed a discrete mode of phase transformation at the particle level. Besides, the preferred electrochemical transport network, particularly the carbon content, was found to govern the sequence of phase transformation among particles. In contrast, at the macroscopic level, studies conducted at four different discharge rates showed a continuous but delayed phase transformation. These findings uncovered the intricate phase transformation in LiFePO4 and potentially offer valuable insights into optimizing the length‐scale‐dependent properties of battery materials. 相似文献
54.
Jian Li Jiangtao Fan Sajjad Ali Guojun Lan Haodong Tang Wenfeng Han Huazhang Liu Bo Li Ying Li 《催化学报》2019,40(2):141-146
Thermal stability of HgCl2 has a pivotal importance for the hydrochlorination reaction as the loss of mercuric compounds is toxic and detrimental to environment. Here we report a low-mercury catalyst which has durability over 10000 h for acetylene hydrochlorination under the industrial condition. The stability of the catalyst is carefully analyzed from a combined experimental and density functional theory study. The analysis shows that the extraordinary stability of mercury catalyst is resulted from the synergy effects between surface oxygen groups and defective edge sites. The binding energy of HgCl2 is increased to be higher than 130 kJ/mol when adsorption is at the edge site with a nearby oxygen group. Therefore, the present study revealed that the thermal stability problem of mercury-based catalyst can be solved by simply adjusting the surface chemistry of activated carbon. Furthermore, the reported catalyst has already been successfully applied in the commercialized production of vinyl chloride. 相似文献
55.
For the first time, to the best of authors’ knowledge, a no-moving-parts axial scanning confocal microscope (ASCM) system is designed and demonstrated using a combination of a large diameter liquid crystal (LC) lens and a classical microscope objective lens. By electrically controlling the 5 mm diameter LC lens, the 633 nm wavelength focal spot is moved continuously over a 48 μm range with a measured 3-dB axial resolution of 3.1 μm using a 0.65 numerical aperture (NA) micro-objective lens. The ASCM is successfully used to image an Indium Phosphide (InP) twin square optical waveguide sample with a 10.2 μm waveguide pitch and 2.3 μm height and width. Using fine analog electrical control of the LC lens, a super-fine sub-wavelength axial resolution of 270 nm is demonstrated. The proposed ASCM can be useful in various precision three-dimensional (3D) imaging and profiling applications. 相似文献
56.
Farzad Nikpour Sajjad Mohebbi Touraj Paibast Mahdi Beigvand 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):663-667
A regio- and stereoselective synthesis of functionalized 4,5-disubstituted oxazolidin-2-ones is reported with moderate to
good yields from the reaction of α-epoxyketones with urea in the presence of p-toluenesulfonic acid as the catalyst.
Correspondence: Farzad Nikpour, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416,
Sanandaj, Iran. 相似文献
57.
Slide-away discharges are achieved by decreasing the plasma density or ramping down the plasma current in runaway discharges in the HT-7 tokamak. In the case of plasma current ramp down, the ratio of the electron plasma frequency to the electron cyclotron frequency is higher than in the stationary pulses when the discharge goes into a slide-away regime. The instability regime is characterized by relaxations in the electron cyclotron emission due to relativistic anomalous Doppler effect which transfers energy from parallel to perpendicular motion. The triggering of relativistic anomalous Doppler effect at higher density by ramping down of plasma current may provide a alternative runaway energy control scenario. 相似文献
58.
59.
We investigate the evolution of a discrete-time one-dimensional quantum walk driven by a position-dependent coin. The rotation angle, which depends upon the position of a quantum particle, parameterizes the coin operator. For different values of the rotation angle, we observe that such a coin leads to a variety of probability distributions, e.g. localized, periodic, classicallike, semi-classical-like, and quantum-like. Further, we study the Shannon entropy associated with position and the coin space of a quantum particle, and compare them with the case of the position-independent coin. Our results show that the entropy is smaller for most values of the rotation angle as compared to the case of the position-independent coin. We also study the effect of entanglement on the behavior of probability distribution and Shannon entropy by considering a quantum walk with two identical position-dependent entangled coins. We observe that in general, a wave function becomes more localized as compared to the case of the positionindependent coin and hence the corresponding Shannon entropy is lower. Our results show that a position-dependent coin can be used as a controlling tool of quantum walks. 相似文献
60.