全文获取类型
收费全文 | 1901篇 |
免费 | 23篇 |
国内免费 | 3篇 |
专业分类
化学 | 1254篇 |
晶体学 | 5篇 |
力学 | 17篇 |
数学 | 189篇 |
物理学 | 462篇 |
出版年
2016年 | 27篇 |
2015年 | 17篇 |
2014年 | 22篇 |
2013年 | 42篇 |
2012年 | 56篇 |
2011年 | 51篇 |
2010年 | 39篇 |
2009年 | 28篇 |
2008年 | 37篇 |
2007年 | 46篇 |
2006年 | 44篇 |
2005年 | 48篇 |
2004年 | 47篇 |
2003年 | 27篇 |
2002年 | 31篇 |
2001年 | 43篇 |
2000年 | 37篇 |
1999年 | 28篇 |
1998年 | 30篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 26篇 |
1994年 | 24篇 |
1993年 | 34篇 |
1992年 | 24篇 |
1991年 | 31篇 |
1990年 | 31篇 |
1989年 | 19篇 |
1988年 | 33篇 |
1987年 | 20篇 |
1986年 | 18篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1982年 | 20篇 |
1980年 | 27篇 |
1979年 | 34篇 |
1978年 | 31篇 |
1977年 | 52篇 |
1976年 | 37篇 |
1975年 | 37篇 |
1974年 | 40篇 |
1973年 | 39篇 |
1972年 | 38篇 |
1971年 | 29篇 |
1970年 | 21篇 |
1969年 | 30篇 |
1968年 | 31篇 |
1967年 | 38篇 |
1966年 | 28篇 |
1933年 | 16篇 |
排序方式: 共有1927条查询结果,搜索用时 15 毫秒
161.
162.
The application of exponential integrators based on Krylov techniques to large‐scale simulations of complex fluid flows with multiple time‐scales demonstrates the efficiency of these schemes in reducing the associated time‐step restrictions due to numerical stiffness. Savings of approximately 50% can be achieved for simulations of the three‐dimensional compressible Navier–Stokes equations while still maintaining a truncation error typical of explicit time‐stepping schemes. Exponential time integration techniques of this type are particularly advantageous for fluid flows with a wide range of temporal scales such as low‐Mach number, reactive or acoustically dominated flows. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
163.
164.
165.
Instrumental neutron activation analysis (INAA) was used to determine 29 elements in pumice from several volcanic sources
(Milos, Nisyros, Yali, Kos and Thera) in the Aegean Sea, Greece, to establish a data basis for the identification of pumice
and tephra layers found in archaeological context. The widespread products of the “Minoan Eruption” of the Thera volcano can
now be distinguished clearly from all other sources and will be used to establish a datumline in the Eastern Mediterranean
Region in the second millenium B.C. The elements Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb,
Sb, Sc, Sm, Ta, Ti, Th, U, V, Yb and Zr were determined in 14 samples from Milos, 25 samples from Nisyros, 7 samples from
Yali, 7 samples from Kos and 17 samples from Thera. Two cycles of irradiation and four measurement runs were applied. The
results were compared and suitable groups, typical for each island, were classified. Due to insufficiently comparable data
sets, the criteria for distinguishing the different sources have not been revealed by previous studies. This basic knowledge
was used to relate pumice from excavations in Tell-el-Dab'a (Egypt) and Bronze Age Knossos to their specific volcanic origin. 相似文献
166.
P. Schmid K. Uran F. Macherey M. Ebert H.-J. Ullrich D. Sommer F. Friedel 《Analytical and bioanalytical chemistry》2009,393(8):1863-1870
The formation of Fe–Zn intermetallic compounds, as relevant in the commercial product galvannealed steel sheet, was investigated
by scanning electron microscopy and different methods of X-ray diffraction. A scanning electron microscope with high resolution
was applied to investigate the layers of the galvannealed coating and its topography. Grazing incidence X-ray diffraction
(GID) was preferred over conventional Bragg–Brentano geometry for analysing thin crystalline layers because of its lower incidence
angle α and its lower depth of information. Furthermore, in situ experiments at an environmental scanning electron microscope (ESEM)
with an internal heating plate and at an X-ray diffractometer equipped with a high-temperature chamber were carried out. Thus,
it was possible to investigate the phase evolution during heat treatment by X-ray diffraction and to display the growth of
the ζ crystals in the ESEM. 相似文献
167.
168.
Ohne Zusammenfassung 相似文献
169.
170.