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121.
Nonlinear Polarization Rotation-Based Mode-Locked Erbium-Doped Fiber Laser with Three Switchable Operation States 下载免费PDF全文
A simple mode-locked erbium-doped fiber laser (EDFL) with three switchable operation states is proposed and demonstrated based on nonlinear polarization rotation. The EDFL generates a stable square pulse at a third harmonic pulse repetition rate of 87kHz as the 1480 nm pump power increases from the threshold of 17.5 m W to 34.3mW. The square pulse duration increases from 105 ns to 245ns as the pump power increases within this region. The pulse operation switches to the second operation state as the pump power is varied from 48.2mW to l16.Tm W. The laser operates at a fundamental repetition rate of 29 kHz with a fixed pulse width of 8.5 μs within the pump power region. At a pump power of ll6.TmW, the average output power is 3.84mW, which corresponds to the pulse energy of 131.5 ng. When the pump power continues to increase, the pulse train experiences unstable oscillation before it reaches the third stable operation state within a pump power region of 138.9 m W to 145.0 m W. Within this region, the EDFL produces a fixed pulse width of 2.8 μs and a harmonic pulse repetition rate of 58 kHz. 相似文献
122.
This paper reports a microchip with an integrated passive micromixer based on chaotic advection. The micromixer with staggered herringbone structures was used for luminol-peroxide chemiluminescence detection. The micromixer was examined to assess its suitability for chemiluminescence reaction. The relationship between the flow rate and the location of maximum chemiluminescence intensity was investigated. The light intensity was detected using an optical fiber attached along the mixing channel and a photon detector. A linear correlation between chemiluminescence intensity and the concentration of cobalt(ii) ions or hydrogen peroxide was observed. This microchip has a potential application in environmental monitoring for industries involved in heavy metals and in medical diagnostics. 相似文献
123.
Separation and fragmentation study of isocoproporphyrin derivatives by UHPLC‐ESI‐exact mass MS/MS and identification of a new isocoproporphyrin sulfonic acid metabolite 下载免费PDF全文
Christopher M. Benton Chang Kee Lim Caje Moniz Sinéad L. Baxter Donald J. L. Jones 《Journal of mass spectrometry : JMS》2014,49(1):80-85
Isocoproporphyrin and its derivatives are commonly used as biomarkers of porphyria cutanea tarda, heavy metal toxicity and hexachlorobenzene (HCB) intoxication in humans and animals. However, most are isobaric with other porphyrins and reference materials are unavailable commercially. The structural characterisation of these porphyrins is important but very little data is available. We report here the separation and characterisation of isocoproporphyrin, deethylisocoproporphyrin, hydroxyisocoproporphyrin and ketoisocoproporphyrin, isolated in the faeces of rats fed with a diet containing HCB, by ultra high performance liquid chromatography‐exact mass tandem mass spectrometry (UHPLC‐MS/MS). Furthermore, we report the identification and characterisation of a previously unreported porphyrin metabolite, isocoproporphyrin sulfonic acid isolated in the rat faeces. The measured mass‐to‐charge ratio (m/z) of the precursor ion was m/z 735.2338, corresponding to a molecular formula of C36H39N4O11S with an error of 0.3 ppm from the calculated m/z 735.2336. The MS/MS data was consistent with an isocoproporphyrin sulfonic acid structure, derived from dehydroisocoproporphyrinogen by sulfonation of the vinyl group. The metabolite was present in a greater abundance than other isocoproporphyrin derivatives and may be a more useful biomarker for HCB intoxication. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
124.
The structure of PhHg(S2CNPr2) shows a distorted linear geometry about mercury defined by a sulfur and a carbon atom. Centrosymmetric molecules aggregate via Hg?S interactions to form loosely associated dimers. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
125.
The structure of As(S2CNMe2)3 has approximate threefold symmetry and features essentially monodentate dithiocarbamate ligands, so that the geometry is trigonal pyramidal. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
126.
This paper investigates the Rouquier blocks of the Hecke algebras of the symmetric groups and the Rouquier blocks of the q-Schur algebras. We first give an algorithm for computing the decomposition numbers of these blocks in the ``abelian defect
group case' and then use this algorithm to explicitly compute the decomposition numbers in a Rouquier block. For fields of
characteristic zero, or when q=1 these results are known; significantly, our results also hold for fields of positive characteristic with q≠1. We also discuss the Rouquier blocks in the ``non–abelian defect group' case. Finally, we apply these results to show
that certain Specht modules are irreducible. 相似文献
127.
The mononuclear structure of Zn(S2CN(CH2)4)2(4,7‐Ph2‐1,10‐phenanthroline) shows the zinc atom in each of the two independent molecules comprising the asymmetric unit to exist in a distorted octahedral geometry defined by an N2S4 donor set. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
128.
The mononuclear structure of Cd(S2CNEt2)2(2,9‐Me2‐1,10‐phenanthroline) shows symmetric coordination of the dithiocarbamate ligands and a distorted octahedral geometry for cadmium, defined by an N2S4 donor set, results. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
129.
130.
Chi‐Ming Che Prof. Hai‐Feng Xiang Dr. Stephen Sin‐Yin Chui Dr. Zong‐Xiang Xu V. A. L. Roy Dr. Jessie Jing Yan Wen‐Fu Fu Prof. P. T. Lai Prof. Ian D. Williams Prof. 《化学:亚洲杂志》2008,3(7):1092-1103
Organic field‐effect transistors incorporating planar π‐conjugated metal‐free macrocycles and their metal derivatives are fabricated by vacuum deposition. The crystal structures of [H2(OX)] (H2OX=etioporphyrin‐I), [Cu(OX)], [Pt(OX)], and [Pt(TBP)] (H2TBP=tetra‐(n‐butyl)porphyrin) as determined by single crystal X‐ray diffraction (XRD), reveal the absence of occluded solvent molecules. The field‐effect transistors (FETs) made from thin films of all these metal‐free macrocycles and their metal derivatives show a p‐type semiconductor behavior with a charge mobility (μ) ranging from 10?6 to 10?1 cm2 V?1 s?1. Annealing the as‐deposited Pt(OX) film leads to the formation of a polycrystalline film that exhibits excellent overall charge transport properties with a charge mobility of up to 3.2×10?1 cm2 V?1 s?1, which is the best value reported for a metalloporphyrin. Compared with their metal derivatives, the field‐effect transistors made from thin films of metal‐free macrocycles (except tetra‐(n‐propyl)porphycene) have significantly lower μ values (3.0×10?6–3.7×10?5 cm2 V?1 s?1). 相似文献