全文获取类型
收费全文 | 178篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 90篇 |
晶体学 | 1篇 |
数学 | 38篇 |
物理学 | 53篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 17篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 296 毫秒
1.
2.
Headspace gas chromatography-mass spectrometry (GC-MS) has been successfully applied to the analysis of the highly volatile species trimethyl amine (TMA). TMA quantitation in fiberglass insulation resins (ultimately used by the automotive and building products industries) is of interest because of its highly odoriferous nature. The release of TMA from fiberglass insulation products is the principal component responsible for the "fishy" odor encountered in automobiles. Currently, the industry standard for the analysis of TMA involves injecting an aqueous insulation extract into the GC-MS equipped with a polyethylene glycol column. Several problems inherent in this analysis prohibit consistent performance and enhance the possibility for wide variations in the quantitative results. This article reports the development of a new approach to the quantitation of TMA from fiberglass insulation between the levels of 1 and 150 ppm. 相似文献
3.
The fluorescence lifetime of Nile Red (NR) is not sensitive to dielectric solvent–solute interactions but markedly decreases with the increase of the hydrogen bond donating ability in alcohols because vibrations associated with hydrogen bonding are involved in the deactivation process. The negligible viscosity effect indicates that twisting of the diethylamino moiety of NR does not play significant role in the dissipation of the excitation energy. 相似文献
4.
5.
6.
Harshal P. Mungse Niharika Bhakuni Deependra Tripathi Om P. Sharma Bir Sain Om P. Khatri 《Journal of Physical Organic Chemistry》2014,27(12):944-951
Graphene oxide (GrO) prepared by the Hummers method was separated into three different fractions (GrO5000, GrO2000, and GrOres) on the basis of their dispersion stability in the water. Infrared, nuclear magnetic resonance, X‐ray photoelectron spectroscopy, and elemental analyses revealed that GrO5000 possesses a high degree of oxygen functionalities including phenolic, carboxylic, and ?OSO2H groups, compared with the other fractions. The GrO5000 was found to be a highly efficient and reusable solid catalyst for the esterification of various carboxylic acids with a variety of alcohols to furnish corresponding esters in high to excellent yields. The catalytic activity of the GrO5000 was attributed to the ability of highly polar GrO5000 scaffold to adsorb/attract reactants, where the acid functionalities of GrO5000 facilitated the esterification process efficiently. The chemical and structural features of GrO5000 were discussed to understand the improved catalytic activity compared with GrO2000 and conventional solid acid catalysts. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
Organic ammonium tribromide (OATB), N-methylpyrrolidine-2-one hydrotribromide (MPHT) was found to be an efficient catalyst for the regioselective ring opening of epoxides with various nucleophiles under solvent free conditions. This procedure occurs under neutral and mild reaction conditions with out adding any additive and afforded high yields of products.
8.
Lublóy Éva Biró András Hlavička Viktor Németh Zsolt Csanaky Judit 《Journal of Thermal Analysis and Calorimetry》2022,147(21):11693-11704
Journal of Thermal Analysis and Calorimetry - Fire protection of steel structures is playing an increasingly important role nowadays. The fire protection of steel structures can be solved with... 相似文献
9.
Strange particle production in heavy ion collisions is calculated in the framework of a hadrochemical model. It is compared with the results of cascade and fireball model calculations and experimental data. The importance of πN and πΔ collisions in producing kaons and hyperons is pointed out. 相似文献
10.
G. Balázs S. Doszlop O. Biró L. Palotás 《Journal of Thermal Analysis and Calorimetry》1990,36(5):1861-1865
It has been proved that the basic oxidative stability of butyl elastomer can be evaluated of isothermal calorimetry. Similarly, the effects of ozone and of thermooxidation can be followed by this method. The isothermal curves for the photooxidation of the elastomer gave a complex pattern, so here it seems necessary to use other methods (IR, UC, GPC dissolving/swelling, DTA, etc.) to determine the remaining stability.
Zusammenfassung Es wurde erwiesen, da\ die grundlegende oxidative StabilitÄt von Butylelastomeren mittels isothermer Kalorimetrie ermittelt werden kann. Analog können mit diesem Verfahren der Einflu\ von Ozon und Thermooxidation untersucht werden. Isotherme Kurven für die Photooxidation der Elastomere liefern ein kompliziertes Bild, hier scheint die Anwendung anderer Methoden (IR, UC, GPC, Löslichkeit, Quellvermögen, DTA usw.) erforderlich zu sein, um die verbleibende StabilitÄt zu bestimmen.相似文献