全文获取类型
收费全文 | 78篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
化学 | 31篇 |
晶体学 | 3篇 |
力学 | 2篇 |
综合类 | 1篇 |
数学 | 24篇 |
物理学 | 23篇 |
出版年
2022年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有84条查询结果,搜索用时 46 毫秒
41.
针对软件统计测试中随机测试和分域测试的优劣问题,章对这两种测试方法进行了全面的比较,从理论上证明了分域测试优于随机测试。并根据软件验收的实际情况,提出了一种改进的软件测试方法,该方法有较好的测试效率。 相似文献
42.
Cheng-yi Zhang Fengmin Xu Zongben Xu Jicheng Li 《Frontiers of Mathematics in China》2014,9(5):1141-1168
The definitions of θ-ray pattern proposed to establish some new results matrix and θ-ray matrix are firstly on nonsingularity/singularity and convergence of general H-matrices. Then some conditions on the matrix A ∈ C^n×n and nonempty α (n) = {1,2,... ,n} are proposed such that A is an invertible H-matrix if A(α) and A/α are both invertible H-matrices. Furthermore, the important results on Schur complement for general H-matrices are presented to give the different necessary and sufficient conditions for the matrix A E HM and the subset α C (n) such that the Schur complement matrix A/α∈ HI^n-|α| or A/α ∈ Hn-|α|^M or A/α ∈ H^n-| α|^S. 相似文献
43.
随着国际恐怖袭击事件的增多,痕量爆炸物的识别技术研究越来越为重要.本文以作者在该领域的研究为例,综述了基于一维有机纳米材料、荧光金属配位聚合物(金属-有机框架化合物)和聚噻咯的荧光猝灭技术,在痕量爆炸物识别上的应用.同时介绍了酞菁薄膜和苝亚酰胺纳米线制备的电子传感器分别对过氧化物和硝基类爆炸物有灵敏的响应. 相似文献
44.
This paper uses a direct simulation Monte Carlo (DSMC) approach to simulate rarefied aerodynamic characteristics during the aerobraking process of the NASA Mars Global Surveyor (MGS) spacecraft. The research focuses on the flowfield and aerodynamic characteristics distribution under various free stream densities. The vari- ation regularity of aerodynamic coefficients is analyzed. The paper also develops an aerodynamics-aeroheating-trajectory integrative simulation model to preliminarily calculate the aerobraking orbit transfer by combining the DSMC technique and the classical kinematics theory. The results show that the effect of the planetary atmospheric density, the spacecraft yaw, and the pitch attitudes on the spacecraft aerodynamics is significant. The numerical results are in good agreement with the existing results reported in the literature. The aerodynamics-aeroheating-trajectory integrative simulation model can simulate the orbit transfer in the complete aerobraking mission. The current results of the spacecraft trajectory show that the aerobraking maneuvers have good performance of attitude control. 相似文献
46.
孔雀石绿是一种人工合成的三苯甲烷类化合物.孔雀石绿的常规检测方法前期处理复杂、耗时长、需要使用大型仪器等缺点导致不能及时的对其进行检测.所以研究出一种能够高效、便捷、快速的检测孔雀石绿残留的方法具有十分重要的意义.分子印迹聚合物(M IPs)是一种多孔隙材料,具有特定的识别位点,可以对特定的目标分子进行识别和吸附.稀土... 相似文献
47.
Campos KR Klapars A Kohmura Y Pollard D Ishibashi H Kato S Takezawa A Waldman JH Wallace DJ Chen CY Yasuda N 《Organic letters》2011,13(5):1004-1007
A convergent and enantioselective route to the hNK-1 receptor antagonist (1) is described, which sets all six stereogenic centers with high diastereoselectivity and delivers 1 in only 11 steps and 23% overall yield. The process was enabled by the development of the enantioselective enzymatic reduction of 3-functionalized cyclopentenones and stereospecific Pd-catalyzed etherification coupling of fragments 6 and 7. 相似文献
48.
The comprehensive model with “weighted-objective nearness degree” is introduced in the process of multi-objective decision-making,
by which a reduction problem of inference antecedents is studied in traditional fuzzy inference method. Moreover, based on
the comprehensive model with “weighted-objective nearness degree”, SMTT fuzzy inference algorithm is proposed. This algorithm
not only shows the relative importance of every antecedent component in fuzzy inference, but also considers the influence
of nearness degree between every antecedent component’s evaluation and inference objective on inference conclusions. The enactment
of inference objective reflects the preference degree of decision maker to every antecedent component’s evaluation. Therefore,
it is much fitter for the demands of practical inference. 相似文献
49.
50.