全文获取类型
收费全文 | 206篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
化学 | 164篇 |
晶体学 | 1篇 |
数学 | 17篇 |
物理学 | 30篇 |
出版年
2020年 | 15篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 13篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 7篇 |
2006年 | 12篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1962年 | 2篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1959年 | 2篇 |
1943年 | 1篇 |
1941年 | 1篇 |
1934年 | 1篇 |
1905年 | 1篇 |
1903年 | 1篇 |
1895年 | 1篇 |
1892年 | 1篇 |
1891年 | 2篇 |
排序方式: 共有212条查询结果,搜索用时 31 毫秒
11.
Codruţa Şoica Adriana Fuliaş Gabriela Vlase Cristina Dehelean Titus Vlase Ionuţ Ledeţi 《Journal of Thermal Analysis and Calorimetry》2014,118(2):1305-1311
Ambazone is a pharmaceutical compound that possesses antiseptic activity and tested as well for anti-tumor properties. Metal complexes of Zn(II), Fe(III), and Cu(II) containing ambazone as ligand were synthesized using a molar ratio salt:ligand of 1:1, heating the mixture up to 50 °C for 6 h. Coordination compounds were characterized by thin-layer chromatography, FT-IR spectroscopy, elemental analysis, and thermal behavior. The non-isothermal experiments were carried out in order to investigate the thermal degradation process of these complexes and were performed in a dynamic air atmosphere at a heating rate β = 10 °C min?1 from ambient temperature, up to 500 °C. It was revealed that decomposition process is a multistadial one. 相似文献
12.
Intrinsic Flexibility of the Zeolitic Imidazolate Framework ZIF‐7 Unveiled by CO2 Adsorption and Hg Intrusion
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Marc Pera‐Titus 《Chemphyschem》2014,15(8):1581-1586
ZIF‐7, built as an assembly of ZnII centers and benzimidazolate ligands, shows prominent S‐shaped isotherms upon CO2 adsorption that can be attributed to sorbate‐induced gate‐opening phenomena involving a narrow‐to‐large pore phase transition. This peculiar sorption pattern can be captured via the formulation of thermodynamic isotherms, providing a direct enthalpic and entropic view of the gate‐opening process. Relying on such an approach, an energy barrier with preferential enthalpic nature for CO2 adsorption/desorption in the gate‐opening region could be unveiled. Moreover, the elastic energy involved during the gate‐opening process was revisited to 1.4–2.8 kJ mol?1 of solid in the temperature range 273–323 K, matching the value measured by isostatic compression of a ZIF‐7_lp sample filled with DMF and showing a dominant entropic contribution. 相似文献
13.
Croitor Lilia Petric Mihaela F. Vlase Gabriela Vlase Titus Siminel Anatolii V. Bourosh Paulina N. Crisan Manuela E. 《Journal of Thermal Analysis and Calorimetry》2020,141(3):973-979
Journal of Thermal Analysis and Calorimetry - Acid–base multicomponent systems based on active pharmaceutical ingredients 2-chloro-5-nitrobenzoic acid (2Cl5NBH) and monoethanolamine were... 相似文献
14.
15.
16.
17.
Titus Schindler 《Monatshefte für Chemie / Chemical Monthly》1891,12(1):637-638
Ohne Zusammenfassung 相似文献
18.
Grasping the historical volatility of stock market indices and accurately estimating are two of the major focuses of those involved in the financial securities industry and derivative instruments pricing. This paper presents the results of employing the intrinsic entropy model as a substitute for estimating the volatility of stock market indices. Diverging from the widely used volatility models that take into account only the elements related to the traded prices, namely the open, high, low, and close prices of a trading day (OHLC), the intrinsic entropy model takes into account the traded volumes during the considered time frame as well. We adjust the intraday intrinsic entropy model that we introduced earlier for exchange-traded securities in order to connect daily OHLC prices with the ratio of the corresponding daily volume to the overall volume traded in the considered period. The intrinsic entropy model conceptualizes this ratio as entropic probability or market credence assigned to the corresponding price level. The intrinsic entropy is computed using historical daily data for traded market indices (S&P 500, Dow 30, NYSE Composite, NASDAQ Composite, Nikkei 225, and Hang Seng Index). We compare the results produced by the intrinsic entropy model with the volatility estimates obtained for the same data sets using widely employed industry volatility estimators. The intrinsic entropy model proves to consistently deliver reliable estimates for various time frames while showing peculiarly high values for the coefficient of variation, with the estimates falling in a significantly lower interval range compared with those provided by the other advanced volatility estimators. 相似文献
19.
Alexander Aerts Dr. Mohamed Haouas Dr. Tom P. Caremans Lana R. A. Follens Dr. Titus S. van Erp Dr. Francis Taulelle Dr. Jan Vermant Prof. Johan A. Martens Prof. Christine E. A. Kirschhock Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(9):2764-2774
Colloidal silicalite‐1 zeolite was crystallized from a concentrated clear sol prepared from tetraethylorthosilicate (TEOS) and aqueous tetrapropylammonium hydroxide (TPAOH) solution at 95 °C. The silicate speciation was monitored by using dynamic light scattering (DLS), synchrotron small‐angle X‐ray scattering (SAXS), and quantitative liquid‐state 29Si NMR spectroscopy. The silicon atoms were present in dissolved oligomers, two discrete nanoparticle populations approximately 2 and 6 nm in size, and crystals. On the basis of new insight into the evolution of the different nanoparticle populations and of the silicate connectivity in the nanoparticles, a refined crystallization mechanism was derived. Upon combining the reagents, different types of nanoparticles (ca. 2 nm) are formed. A fraction of these nanoparticles with the least condensed silicate structure does not participate in the crystallization process. After completion of the crystallization, they represent the residual silicon atoms. Nanoparticles with a more condensed silicate network grow until approximately 6 nm and evolve into building blocks for nucleation and growth of the silicalite‐1 crystals. The silicate network connectivity of nanoparticles suitable for nucleation and growth increasingly resembles that of the final zeolite. This new insight into the two classes of nanoparticles will be useful to tune the syntheses of silicalite‐1 for maximum yield. 相似文献
20.
Madalina Tudose Florin D. Badea Gabriela Ionita Maria Maganu Miron T. Caproiu Petre Ionita Titus Constantinescu Alexandru T. Balaban 《Structural chemistry》2010,21(6):1227-1234
Starting from 4-chloro-3,5-dinitrobenzoic acid 1, compounds 2–10 (N-alkoxy-3,5-dinitro-4-aminobenzoic acid esters where alkoxy stands for methoxy, carboxymethoxy, triphenylmethoxy, or corresponding
amides) have been obtained, from which compounds 3–5 and 7–10 are new, and for the known compounds 2 and 6 the synthetic procedure has been improved. The new derivatives have been characterized by appropriate means (IR, UV–Vis,
1H- and 13C-NMR, fluorescence) and their properties were studied. Thus, depending on their structure, the compounds have acid properties,
fluorescence and complexing properties with alkaline cations. 相似文献