全文获取类型
收费全文 | 239篇 |
免费 | 11篇 |
专业分类
化学 | 149篇 |
晶体学 | 1篇 |
力学 | 7篇 |
数学 | 29篇 |
物理学 | 64篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 9篇 |
2012年 | 14篇 |
2011年 | 25篇 |
2010年 | 11篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1960年 | 1篇 |
1934年 | 1篇 |
1919年 | 1篇 |
1913年 | 2篇 |
1906年 | 1篇 |
1893年 | 1篇 |
1882年 | 1篇 |
排序方式: 共有250条查询结果,搜索用时 15 毫秒
71.
Schuster ME Hävecker M Arrigo R Blume R Knauer M Ivleva NP Su DS Niessner R Schlögl R 《The journal of physical chemistry. A》2011,115(12):2568-2580
Diesel soot (Euro IV and Euro VI) was investigated with spectroscopic methods such as near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray photoemission spectroscopy (XPS). C and O K-edge NEXAFS show that structural disorder on the surface is accompanied by a higher amount of oxygen functional groups. O K-edge NEXAFS and O1s XPS results are discussed with the aim to elucidate the nature of the oxygen surface species. The analysis of the data presented here allows the postulation of a hypothetical structure for soot samples emitted by diesel engines. 相似文献
72.
Dimeric (gemini) surfactants: effect of the spacer group on the association behavior in aqueous solution 总被引:23,自引:0,他引:23
Zana R 《Journal of colloid and interface science》2002,248(2):203-220
Dimeric (gemini) surfactants are made up of two amphiphilic moieties connected at the level of, or very close to, the head groups by a spacer group of varying nature: hydrophilic or hydrophobic, rigid or flexible. These surfactants represent a new class of surfactants that is finding its way into surfactant-based formulations. The nature of the spacer group (length, flexibility, chemical structure) has been shown to be of the utmost importance in determining the solution properties of aqueous dimeric surfactants. This paper reviews the effect of the nature of the spacer on some of these properties. The behavior of dimeric surfactants in the submicellar range of concentration, at interfaces, in dilute solution (solubility in water, Krafft temperature, critical micellization concentration, thermodynamics of micelle formation, micelle ionization degree, size, polydispersity, micropolarity and microviscosity, microstructure and rheology of the solutions, solubilization, micelle dynamics, and interaction with polymers) and in concentrated solution (phase behavior) are successively reviewed. Selected results concerning trimeric and tetrameric surfactants are also reviewed. 相似文献
73.
74.
Daniel Beaupère Najet Belkhouya Christophe Morin Raoul Uzan Gilles Demailly 《Journal of carbohydrate chemistry》2013,32(1):159-164
Abstract Deoxyhalogenosugars constitute an important class of compounds for the synthesis of other carbohydrate derivatives.1–3 Several members of this class are of interest in their own right, being intensely sweet4, 5 or possessing anti-cariogenic6,7 or male anti-fertility properties.8–11 相似文献
75.
All steps involved in the determination of tributyltin in sediments by anhydrous acetic acid extraction, hydride generation, cold trapping, gas chromatographic separation and quartz furnace atomic absorption spectrometry are critically examined. Detection limits (1.8 ng Sn.g–1) and reproducibility at representative concentration levels (6–12%) are satisfying for practical purposes. 相似文献
76.
Phuoc Dien Pham Vincent Lapinte Yann Raoul Jean‐Jacques Robin 《Journal of polymer science. Part A, Polymer chemistry》2014,52(11):1597-1606
Oleic acid and α,ω‐diacid were converted into propargylic esters followed by thiol‐ene/yne coupling (TEC/TYC) functionalization in presence of mercaptoethanol. The multiradical addition on fatty esters leads to the formation of lipidic polyols (OH1 and OH2), as judged by 1H NMR and mass spectroscopies as well as by size exclusion chromatography. The crosslinking reaction between TEC/TYC‐based polyols and 4,4′‐methylene bis(phenylisocyanate) isocyanate reactant was monitored by FTIR experiment and reaction parameters were optimized. By differential scanning calorimetry, relatively high glass transitions are measured corresponding to structure with little or without dangling chain. Moreover, the thermal stability of the resulting plant oil‐based polyurethane materials (PU1 and PU2) were found to be fully consistent with that of other lipidic PUs respecting a three‐step process. Thanks to TYC methodology, fatty α,ω‐diacid produces lipidic polyol without dangling chain and lipidic thermoset PU with relatively high Tg. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1597–1606 相似文献
77.
Raoul R. Nigmatulin Alexander P. Alekhin Dumitru Baleanu Erdal Dinç Zafer Üstündağ Haslet Ekşi Ali Osman Solak 《Electroanalysis》2010,22(4):419-426
The effect of the potential cycles on the reflective IR signals of nitro‐groups in nanofilms was studied for the statistical characterization of nitrobenzene (NB) and nitroazobenzene (NAB)‐modified glassy carbon (GC) surfaces. Both NB and NAB nanofilms were obtained by the electrochemical reduction of the diazonium tetrafluoroborate salts in acetonitrile using cyclic voltammetry (CV). The modified surfaces were denoted as GC‐(NB)n and GC‐(NAB)n, respectively, where n indicates the number of CV cycles performed during modification. Reflective IR signals of the normalized NB and NAB nanofilms and GC were used for the quantitative evaluation of the effect of the potential cycles on the reflective IR signals of nitro‐groups in nanofilms. The detection and quantitative ‘reading’ of the influence of number of CV cycles were realized in the frame of a new error controllable approach that was applied for analysis of all available set of data. This approach includes in itself the following basic steps: (a) the procedure of the division (normalization) on the GC spectra, (b) the comparison of the smoothed spectra for their statistical proximity in the frame of the statistics of the fractional moments, (c) extraction of possible calibration parameters for possible calibration of the normalized spectra with respect to the number of CV cycles. These three basic steps are becoming effective for detection of the influence of some external factors. In our case it is important to detect the influence of the factor n characterizing CV cycles. 相似文献
78.
Raoul Mens Fatma Demir Guy Van Assche Bruno Van Mele Dirk Vanderzande Peter Adriaensens 《Journal of polymer science. Part A, Polymer chemistry》2012,50(5):1037-1041
In this article, it is demonstrated that doctor blading of thin poly‐3‐hexylthiophene/phenyl‐C61‐butyric acid methyl ester (1/1) bulk‐hetero junction films from toluene leads to an improved nanocrystallinity, when compared with their unannealed chlorobenzene processed counterparts. This difference in morphology was demonstrated by solid‐state NMR and Rapid Heating Cooling Calorimetry (RHC), being useful complementary techniques to investigate the active layer morphology of photovoltaic devices. An increased PC60BM nanocrystallinity is indicated by several NMR relaxation decay times (T1C, T1H, and T1ρH) and confirmed by an increase of the melting enthalpy in RHC experiments. An improved solar cell performance further strengthens this conclusion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
79.
den Hollander MJ Magis JG Fuchsenberger P Aartsma TJ Jones MR Frese RN 《Langmuir : the ACS journal of surfaces and colloids》2011,27(16):10282-10294
The utilization of proteins as nanodevices for solar cells, bioelectronics, and sensors generally necessitates the transfer of electrons to or from a conducting material. Here we report on efforts to maximize photocurrent generation by bacterial photosynthetic reaction center pigment-protein complexes (RCs) interfaced with a metal electrode. The possibility of adhering RCs to a bare gold electrode was investigated with a view to minimizing the distance for electron tunneling between the protein-embedded electron-transfer cofactors and the metal surface. Substantial photocurrents were achieved despite the absence of coating layers on the electrode or engineered linkers to achieve the oriented deposition of RCs on the surface. Comparison with SAM-covered gold electrodes indicating enhanced photocurrent densities was achieved because of the absence of an insulating layer between the photoactive pigments and the metal. Utilizing RCs surrounded by light-harvesting 1 complex resulted in higher photocurrents, surprisingly not due to enhanced photoabsorption but likely due to better surface coverage of uniformly oriented RC-LH1 complexes and the presence of a tetraheme cytochrome that could act as a connecting wire. The introduction of cytochrome-c (cyt-c) as a molecular relay also produced increases in current, probably by intercalating between the adhered RCs or RC-LH1 complexes and the electrode to mediate electron transfer. Varying the order in which components were introduced to the electrode indicated that dynamic rearrangements of RCs and cyt-c occurred at the bare metal surface. An upper limit for current generation could not be detected within the range of the illumination power available, with the maximum current density achieved by RC-LH1 complexes being on the order of 25 μA/cm(2). High currents could be generated consecutively for several hours or days under ambient conditions. 相似文献
80.
Christoph Rameshan Werner Stadlmayr Christian Weilach Simon Penner Dr. Harald Lorenz Michael Hävecker Dr. Raoul Blume Dr. Tulio Rocha Dr. Detre Teschner Dr. Axel Knop‐Gericke Dr. Robert Schlögl Prof. Norbert Memmel Prof. Dmitry Zemlyanov Dr. Günther Rupprechter Prof. Bernhard Klötzer Dr. 《Angewandte Chemie (International ed. in English)》2010,49(18):3224-3227