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91.
Wai Yi Kelly Chan T. W. Dominic Chan Peter B. O’Connor 《Journal of the American Society for Mass Spectrometry》2010,21(6):1012-1015
Electron-transfer dissociation (ETD) with supplemental activation of the doubly charged deamidated tryptic digested peptide
ions allows differentiation of isoaspartic acid and aspartic acid residues using the c + 57 or z • − 57 peaks. The diagnostic peak clearly localizes and characterizes the isoaspartic acid residue. Supplemental activation
in ETD of the doubly charged peptide ions involves resonant excitation of the charge reduced precursor radical cations and
leads to further dissociation, including extra backbone cleavages and secondary fragmentation. Supplemental activation is
essential to obtain a high quality ETD spectrum (especially for doubly charged peptide ions) with sequence information. Unfortunately,
the low-resolution of the ion trap mass spectrometer makes detection of the diagnostic peak, [M-60], for the aspartic acid
residue difficult due to interference with side-chain loss from arginine and glutamic acid residues. 相似文献
92.
Dye aggregation is detrimental to the performance of high optical density dye-doped photonic materials. To overcome this challenge,
the ability of cucurbit[7]uril (CB7) as a molecular host to disrupt aggregate formation on glass substrates was examined.
Rhodamine B was covalently attached to glass slides by initially coating the surface with azidohexylsiloxane followed by copper-catalyzed
“click” triazole formation with rhodamine B propargyl ester. The absorption and emission spectra of rhodamine B coated slides
in water indicated diverse heterogeneous properties as surface dye density varied. Fluorescence quenching due to dye aggregation
was evident at high surface dye density. Addition of aqueous cucurbit[7]uril (CB7) to the surface-tethered dyes perturbed
the spectra to reveal a considerable reduction in heterogeneity, which suggested that the presence of a surface in close proximity
does not significantly impair CB7’s ability to complex with tethered rhodamine B. 相似文献
93.
Low temperature quenching and high efficiency CaSc2O4:Ce3+ (CSO:Ce3+) phosphors co-doped with Tm3+, La3+ and Tb3+ ions were prepared by a solid state method and the phase-forming, morphology, luminescence and application properties of these phosphors were investigated. The results showed that co-doping of Tm3+, La3+ and Tb3+ ions can improve the luminescence properties and decrease temperature quenching of CSO:Ce3+ phosphor remarkably. High efficiency green-light-emitting diodes were fabricated with the prepared phosphors and InGaN blue-emitting (∼460 nm) chips. The good performances of the green-light-emitting LEDs made from co-doped CSO:Ce3+ phosphors confirm the luminescence enhancement and indicate that Tm3+, La3+ and Tb3+ co-doped CSO:Ce3+ phosphors are suitable candidates for the fabrication of high efficiency white LEDs. 相似文献
94.
Past research has demonstrated that hologram of a real world object can be acquired by scanning it with a single two-dimensional optical scan. The technology commonly referred to as optical scanning holography (OSH), have found important applications such as in microscopy, pattern recognition, 3D holographic display, and optical remote sensing. As holograms are often employed to capture three dimensional objects with high resolution, large amount of data is required to represent them. In this paper we propose a method for compressing holograms based on Delta modulation. Specifically, we apply our proposed method for holograms captured by OSH. Experimental evaluation reveals that our proposed approach is capable of attaining a compression ratio of 64 times, and still preserves favorable fidelity on the reconstructed images. In addition, both the encoding and decoding processes of the proposed method are very low in complexity, hence enabling real-time operation. 相似文献
95.
ZHONG ZhiYong ZHANG HuaiWu TANG XiaoLi JING YuLan BAI FeiMing & LIU Shuang State Key Laboratory of Electronic Thin Films Integrated Devices University of Electronic Science Technology of China Chengdu China School of Optoelectronic Information 《中国科学:物理学 力学 天文学(英文版)》2011,(7)
The microstructure and magnetic properties of cobalt ferrite thin films deposited by the sputtering method on an Fe3O4 under-layer were investigated at different post-annealing temperatures.Results show that the Fe3O4 under-layer can accelerate the grain growth of cobalt ferrite films due to the phase transformation of the Fe3O4 under-layer at about 400°C-500°C.By introducing the Fe3O4 under-layer,cobalt ferrite nanocrystalline thin films with high coercivity can be obtained at lower post-annealing temperat... 相似文献
96.
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98.
E. A. Podolina O. B. Rudakov Fan Vin Thin L. V. Rudakova 《Journal of Analytical Chemistry》2010,65(2):117-119
A new procedure was developed for the liquid—liquid extraction of phenols from aqueous solutions With acetonitrile. It is based on the ability of aqueous acetonitrile systems to form immiscible phases in the temperature range 271—269 K. The resulting duration of analysis is 40–45 min, the partition coefficient is 45–140, and the recovery is 97.8–99.2%. The procedure was proved applicable for sample pretreatment followed by determination by reversed-phase HPLC. 相似文献
99.
Raymond Wai‐Yin Sun Dr. Carrie Ka‐Lei Li Dr. Dik‐Lung Ma Dr. Jessie Jing Yan Chun‐Nam Lok Dr. Chung‐Hang Leung Dr. Nianyong Zhu Dr. Chi‐Ming Che Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(10):3097-3113
In the design of physiologically stable anticancer gold(III) complexes, we have employed strongly chelating porphyrinato ligands to stabilize a gold(III) ion [Chem. Commun. 2003 , 1718; Coord. Chem. Rev. 2009 , 253, 1682]. In this work, a family of gold(III) tetraarylporphyrins with porphyrinato ligands containing different peripheral substituents on the meso‐aryl rings were prepared, and these complexes were used to study the structure–bioactivity relationship. The cytotoxic IC50 values of [Au(Por)]+ (Por=porphyrinato ligand), which range from 0.033 to >100 μM , correlate with their lipophilicity and cellular uptake. Some of them induce apoptosis and display preferential cytotoxicity toward cancer cells than to normal noncancerous cells. A new gold(III)–porphyrin with saccharide conjugation [Au(4‐glucosyl‐TPP)]Cl ( 2 a ; H2(4‐glucosyl‐TPP)=meso‐tetrakis(4‐β‐D ‐glucosylphenyl)porphyrin) exhibits significant cytostatic activity to cancer cells (IC50=1.2–9.0 μM ) without causing cell death and is much less toxic to lung fibroblast cells (IC50>100 μM ). The gold(III)–porphyrin complexes induce S‐phase cell‐cycle arrest of cancer cells as indicated by flow cytometric analysis, suggesting that the anticancer activity may be, in part, due to termination of DNA replication. The gold(III)–porphyrin complexes can bind to DNA in vitro with binding constants in the range of 4.9×105 to 4.1×106 dm3 mol?1 as determined by absorption titration. Complexes 2 a and [Au(TMPyP)]Cl5 ( 4 a ; [H2TMPyP]4+=meso‐tetrakis(N‐methylpyridinium‐4‐yl)porphyrin) interact with DNA in a manner similar to the DNA intercalator ethidium bromide as revealed by gel mobility shift assays and viscosity measurements. Both of them also inhibited the topoisomerase I induced relaxation of supercoiled DNA. Complex 4 a , a gold(III) derivative of the known G‐quadruplex‐interactive porphyrin [H2TMPyP]4+, can similarly inhibit the amplification of a DNA substrate containing G‐quadruplex structures in a polymerase chain reaction stop assay. In contrast to these reported complexes, complex 2 a and the parental gold(III)–porphyrin 1 a do not display a significant inhibitory effect (<10 %) on telomerase. Based on the results of protein expression analysis and computational docking experiments, the anti‐apoptotic bcl‐2 protein is a potential target for those gold(III)–porphyrin complexes with apoptosis‐inducing properties. Complex 2 a also displays prominent anti‐angiogenic properties in vitro. Taken together, the enhanced stabilization of the gold(III) ion and the ease of structural modification render porphyrins an attractive ligand system in the development of physiologically stable gold(III) complexes with anticancer and anti‐angiogenic activities. 相似文献
100.
本文给出了一类非时齐的Markov链的强逼近.作为应用,建立了临床试验中Markov链自适应设计的强相合性,重对数律和弱收敛. 相似文献