全文获取类型
收费全文 | 138篇 |
免费 | 4篇 |
专业分类
化学 | 75篇 |
力学 | 2篇 |
数学 | 24篇 |
物理学 | 41篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 12篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 8篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1977年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有142条查询结果,搜索用时 0 毫秒
141.
Ruud J. B. Peters Ingrid J. W. Elbers Mirjam D. Klijnstra Alida A. M. Stolker 《Accreditation and quality assurance》2011,16(11):567-574
Nowadays, a lot of time and resources are used to determine the quality of goods and services. As a consequence, the quality
of measurements themselves, e.g., the metrological traceability of the measured quantity values is essential to allow a proper
evaluation of the results with regard to specifications and regulatory limits. This requires knowledge of the measurement
uncertainties of all quantity values involved in the measurement procedure, including measurement standards. This study shows
how the uncertainties due to the preparation, as well as the chemical and compositional stability of a chemical measurement
standard, or calibrator, can be estimated. The results show that the relative standard uncertainty of the concentration value
of a typical analytical measurement standard runs up to 2.8% after 1 year. Of this, 1.9% originates from the preparation of
the measurement standard, while 2.0 and 0.53% originate from the chemical and compositional stability during storage at −20 °C.
The monthly preparation of working calibrators stored at 4 °C and used on a weekly basis, results in an additional standard
uncertainty of the analyte concentration value of 0.35% per month due to compositional stability. While the preparation procedure
is the major contributor to the total measurement uncertainty, the uncertainties introduced by the stability measurements
are another important contributor, and therefore, the measurement procedure to evaluate stability is important to minimize
the total measurement uncertainty. 相似文献
142.
Nonperturbative D-brane instantons can generate perturbatively absent though phenomenologically relevant couplings for type II orientifold compactifications with D-branes. We discuss the generation of the perturbatively vanishing SU(5) GUT Yukawa coupling of type <10 10 5(H)>. Moreover, for a simple globally consistent intersecting D6-brane model, we discuss the generation of mass terms for matter fields. This can serve as a mechanism for decoupling exotic matter. 相似文献