全文获取类型
收费全文 | 166篇 |
免费 | 34篇 |
国内免费 | 14篇 |
专业分类
化学 | 104篇 |
晶体学 | 3篇 |
力学 | 6篇 |
综合类 | 1篇 |
数学 | 36篇 |
物理学 | 64篇 |
出版年
2023年 | 16篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 19篇 |
2019年 | 9篇 |
2018年 | 5篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 36篇 |
2012年 | 12篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1985年 | 1篇 |
1980年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有214条查询结果,搜索用时 31 毫秒
91.
Laser Raman Spectroscopy and FT-IR spectroscopy are used for the study of “urinary sand”. The examination of Raman spectra indicates the presence of struvite and apatite in the sample. The FT-IR spectrum is used to evaluate the relative concentration of apatitebtruvite components in the sample. The form of band profile may be correlated to the history of particle growth. 相似文献
92.
《Analytical letters》2012,45(11):821-825
Abstract A rapid field-test of ascorbic acid content in fruit juices is feasible by the application of indicator papers capable for approximate quantitation. 相似文献
93.
《Optimization》2012,61(1-4):309-341
Let Xbe a setW set of extended-real valued functions on Xand 0 an element of Xsuch that w(0) = 0 for all win W. We give a general theory of dual representations, without any extra parameters, of various hulls for extended-real valued functions on X satisfying f(0)= inf f(X\{0})We use the unifying framework of quasi-convex functions with respect to families of subsets of Xand a condition generalizing the bipolar theorem. Our results contain, as particular cases, some recent results of Thach (1991, 1993) and Rubinov and Glover (1996) on W-pseudo-affine and W-quasi-coaffine hulls.We also give some results in the converse direction. These yield, in particular, that the bipolar theorem is equivalent to a certain property of the lower semi-continuous quasi-convex hulls of functions on locally convex spaces 相似文献
94.
95.
Hg2+可以猝灭核黄素的荧光,碘离子(I-)可以与Hg2+形成HgI2,基于此,发展了一种新型的荧光增强法检测水中I-的方法。Hg2+加入后,核黄素在525 nm处的荧光被猝灭;继续在体系中加入不同浓度的I-,体系中Hg2+被不断消耗,导致核黄素在525 nm处的荧光逐渐增强。该方法检测I-的线性范围在1-100μmol·L-1,检测限是0.4μmol·L-1;同时,该方法具有较快的响应时间(2 min);对其他卤素离子具有较好的选择性;用于水中I-检测时得到了较好的回收率。 相似文献
96.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):529-548
The effect of 1,4-dioxane as an added base on the cationic polymerization of isobutyl vinyl ether (IBVE) initiated by carboxyl groups on carbon black surface/ethylaluminum dichloride (EtAlCl2) system was investigated. Although the cationic polymerization of IBVE by carbon black/EtAlCl2 system the absence of 1,4-dioxane instaneously proceeded and the monomer conversion achieved 100% within a minute. The molecular weight distribution (MWD) of polyIBVE obtained was very broad. On the contrary, the MWD of polyIBVE obtained was very narrow and narrower than that obtained from the carbon black/ZnCl2 initiating system by the addition of 1,4-dioxane. The number-average molecular weight (Mn) of polyIBVE obtained was directly proportional to monomer conversion in the cationic polymerization. However, the Mn of polyIBVE obtained from the polymerization by the initiating system in the the presence of 1,4-dioxane was smaller than that of the calculated value, assuming that polyl(IBVE) chain forms per unit carboxyl group on carbon black surface. It was concluded that carbon black/EtAlCl2 initiating systems in the presence of 1,4-dioxane has an ability to initiate “living-like” cationic polymerization of IBVE based on the above results. PolyIBVE was grafted onto a carbon black surface after quenching the above “living-like” cationic polymerization systems with methanol. 相似文献
97.
98.
99.
100.
Francesco Calogero 《Journal of Nonlinear Mathematical Physics》2013,20(3):348-354
Some properties—including relations having a Diophantine character—of the zeros of the sum of two polynomials are reported. 相似文献