全文获取类型
收费全文 | 5602篇 |
免费 | 130篇 |
国内免费 | 23篇 |
专业分类
化学 | 3615篇 |
晶体学 | 46篇 |
力学 | 103篇 |
数学 | 631篇 |
物理学 | 1360篇 |
出版年
2021年 | 31篇 |
2020年 | 62篇 |
2019年 | 67篇 |
2018年 | 30篇 |
2016年 | 101篇 |
2015年 | 87篇 |
2014年 | 93篇 |
2013年 | 189篇 |
2012年 | 219篇 |
2011年 | 277篇 |
2010年 | 142篇 |
2009年 | 130篇 |
2008年 | 268篇 |
2007年 | 219篇 |
2006年 | 230篇 |
2005年 | 216篇 |
2004年 | 165篇 |
2003年 | 157篇 |
2002年 | 165篇 |
2001年 | 123篇 |
2000年 | 114篇 |
1999年 | 88篇 |
1998年 | 95篇 |
1997年 | 69篇 |
1996年 | 96篇 |
1995年 | 85篇 |
1994年 | 72篇 |
1993年 | 88篇 |
1992年 | 94篇 |
1991年 | 75篇 |
1990年 | 66篇 |
1989年 | 74篇 |
1988年 | 77篇 |
1987年 | 63篇 |
1986年 | 60篇 |
1985年 | 94篇 |
1984年 | 92篇 |
1983年 | 62篇 |
1982年 | 80篇 |
1981年 | 81篇 |
1980年 | 94篇 |
1979年 | 97篇 |
1978年 | 94篇 |
1977年 | 70篇 |
1976年 | 62篇 |
1975年 | 69篇 |
1974年 | 56篇 |
1973年 | 60篇 |
1971年 | 33篇 |
1970年 | 31篇 |
排序方式: 共有5755条查询结果,搜索用时 15 毫秒
1.
Summary Using a saturated non-boiling hydrocarbon mixture, the influence of two parameters on the results of field ionization mass spectrometry (FI-MS) measurements was studied: (a) the potential difference between the FI emitter and the counterelectrode; (b) the emitter temperature.Variation of the potential difference had only a minor effect on the average molecular mass measured and had no evident effect on the relative ring number distribution in the sample. In contrast, when the emitter temperature was increased, higher average molecular masses were recorded. Moreover, the average molecular masses shifted to higher ring numbers. In order to control the relationship between the described influences during mixture analysis, measuring instructions have been developed that enable the quantitative analysis of unknown saturated samples. However, average molecular mass of the mixture must be known.
Entwicklung einer quantitativen FI-MS-Methode zur Charakterisierung von gesättigten hoch- und nichtsiedenden Kohlenwasserstoffgemischen相似文献
2.
J. B. Lewis E. L. Baldeschwieler L. D. Tabern E. F. Shelberg D. Hillis S. Cromer I. F. Bingham S. Givaudon M. Aubert M. R. Moutte A. Andant P. Lambert J. Lecomte J. Tausz H. Wolf B. Gordon W. Dachnow I. Perrier M. Lobunetz M. O. Chaikin C. Engler D. Holde 《Analytical and bioanalytical chemistry》1940,119(7-8):307-310
3.
4.
Feel like writing a review for The Mathematical Intelligencer? You are welcome to submit an unsolicited review of a book of your choice; or, if you would welcome being assigned a book to review, please write us, telling us your expertise and your predilections. 相似文献
5.
Gerald Moore. 《Mathematics of Computation》2004,73(245):211-242
We present an algorithm, based on approximation by Laguerre polynomials, for computing a point on the stable manifold of a stationary solution of an autonomous system. A superconvergence phenomenon means that the accuracy of our results is much higher than the usual spectral accuracy. Both the theory and the implementation of the method are considered. Finally, as an application of the algorithm, we describe a fully spectral approximation of homo- and heteroclinic orbits.
6.
Mark Doyle Susan A. Mulligan Tetsuya Matsuda Gerald M. Pohost 《Magnetic resonance imaging》1992,10(6):887-892
A new “bright blood” strategy, outflow refreshment imaging, is introduced in which a number of overlapping slices are excited in rapid succession. Flowing spins that refresh each overlapped slice portion contribute a bright signal. Additionally, static tissue in each non-overlapped slice portion also yields a bright signal. However, the flow/static contrast is comparable to that produced in inflow refreshment images, and angiograms can be generated by conventional maximum intensity projection processing. The dual ability to visualize angiograms and static tissue images is a major benefit of the strategy. Computer simulations of flow sensitivities and in vivo results are presented which compare the outflow and inflow refreshment imaging strategies. 相似文献
7.
K. Wolf 《Archive of Applied Mechanics (Ingenieur Archiv)》1941,12(4):259-264
Ohne Zusammenfassung 相似文献
8.
9.
10.