全文获取类型
收费全文 | 3176篇 |
免费 | 139篇 |
国内免费 | 20篇 |
专业分类
化学 | 2491篇 |
晶体学 | 7篇 |
力学 | 54篇 |
数学 | 467篇 |
物理学 | 316篇 |
出版年
2023年 | 19篇 |
2022年 | 26篇 |
2021年 | 28篇 |
2020年 | 71篇 |
2019年 | 49篇 |
2018年 | 29篇 |
2017年 | 41篇 |
2016年 | 74篇 |
2015年 | 101篇 |
2014年 | 105篇 |
2013年 | 176篇 |
2012年 | 212篇 |
2011年 | 223篇 |
2010年 | 162篇 |
2009年 | 120篇 |
2008年 | 220篇 |
2007年 | 212篇 |
2006年 | 218篇 |
2005年 | 200篇 |
2004年 | 152篇 |
2003年 | 130篇 |
2002年 | 153篇 |
2001年 | 68篇 |
2000年 | 54篇 |
1999年 | 59篇 |
1998年 | 45篇 |
1997年 | 52篇 |
1996年 | 58篇 |
1995年 | 44篇 |
1994年 | 31篇 |
1993年 | 23篇 |
1992年 | 22篇 |
1991年 | 11篇 |
1990年 | 17篇 |
1989年 | 14篇 |
1988年 | 4篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有3335条查询结果,搜索用时 15 毫秒
981.
Margarita Guenther Gerald Gerlach Cathrin Corten Dirk Kuckling Martin Muller Zhangman Shi Joerg Sorber Karl-Friedrich Arndt 《Macromolecular Symposia》2007,254(1):314-321
Summary: A rapidly expanding field of on-line process monitoring and on-line control in biotechnology, food industry, pharmaceutical industry, process chemistry, environmental measuring technology, water treatment and sewage processing requires the development of new micro fabricated reliable chemical and biosensors that are specific for particular species and can attain the analytic information in a faster, simpler and cheaper manner. Using a functionalised polymer coating in sensors provides the possibility to detect, transmit and record the information regarding the concentration change or the presence of a specific analyte (a chemical or biological substance that needs to be measured) by producing a signal proportional to the concentration of the target analyte. However, the sensor response time and signal reproducibility are limited by the visco-elastical and hysteresis behaviour of the polymer material. We propose some methods improving the properties of the chemical sensors on the basis of thermo-shrinking N-isopropylacrylamide (NIPAAm) copolymer gels. 相似文献
982.
983.
Since the initial work by I. H. Sloan and his collaborators on the component-by-component construction of good lattice rules for the approximation of multivariate integrals, a lot of variations on this theme have been published. These include various function spaces, prime and composite number of points, intermediate-rank rules, polynomial lattice rules and extensible rules. We sketch the different variations and discuss the properties needed to have a fast component-by-component construction. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
984.
Determination of the Stoichiometric Composition of High-Temperature Superconductors by ICP-OES for Production Control 总被引:1,自引:0,他引:1
A procedure to dissolve and analyse different types of high-temperature superconducting materials in order to determine their
stoichiometric com- position is described. As sample materials Y-Ba-Cu-O and (Pb)Bi-Sr-Ca-Cu-O were analysed. They were dissolved
with hydrochloric acid and analysed by simultaneous ICP-OES, which fits best for this analytical task because of its multielement
capacity, its high precision of determination and accuracy. Each of the relevant metals (Pb, Bi, Sr, Ca, Y, Ba, Cu) could
be determined successfully. The precision of the determination was found to be better than 2% relative standard deviation
and usually even below 1%. The sample preparation and determination procedure described allows a high sample throughput, which
is essential for production control. Also precursors of the superconducting materials (e.g. nitrate solutions) could be analysed
by the procedure described. 相似文献
985.
986.
987.
Claire Adam Jean-Loic Kneur Rémi Lafaye Tilman Plehn Michael Rauch Dirk Zerwas 《The European Physical Journal C - Particles and Fields》2011,71(1):1-19
If supersymmetry is observed at the LHC its model parameters can be measured at the electroweak scale. We discuss the expected precision on the parameter determination, including a proper treatment of experimental and theoretical errors. Particular attention is paid to degenerate solutions. Using the SFitter framework we perform a bottom–up reconstruction of the unified parameters at the high scale, including a full error propagation. 相似文献
988.
989.
Dirk J. A. Senden Johannes A. W. van Dommelen L. E. Govaert 《Journal of Polymer Science.Polymer Physics》2012,50(22):1589-1596
Considering the current view that physical aging of glasses results in an increase of activation barriers to plastic deformation, it is surprising that, until now, no influence of physical aging was observed experimentally on the temperature dependence of plastic deformation in polymeric glasses. This study evaluates why such an influence has not been found, and it is shown that detailed analysis of a set of uniaxial compression data on polycarbonate (PC) at different strain rates and temperatures leads to the conclusion that a significant influence indeed exists. As a consequence, the Eyring activation energy depends on the aging history of the material. These experimental observations are rationalized in terms of a simple physical interpretation of the aging phenomenon. The article also contains a discussion of the apparent deaging of amorphous polymers induced by large‐strain plastic deformation. This discussion is of key importance here, because this study compares yield stresses of aged PC with those of mechanically deaged, or rejuvenated, PC. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
990.
Fortunato Piersimoni Giedrius Degutis Sabine Bertho Koen Vandewal Donato Spoltore Tim Vangerven Jeroen Drijkoningen Marlies K. Van Bael An Hardy Jan D'Haen Wouter Maes Dirk Vanderzande Milos Nesladek Jean Manca 《Journal of Polymer Science.Polymer Physics》2013,51(16):1209-1214
For an increased lifetime of polymer:fullerene bulk heterojunction (BHJ) solar cells, an understanding of the chemical and morphological degradation phenomena taking place under operational conditions is crucial. Phase separation between polymer and fullerene induced by thermal stress has been pointed out as a major issue to overcome. While often the effect of thermal stress on the morphology of polymer:fullerene BHJ is investigated in the darkness, here we observe that light exposure slows down fullerene crystallization and phase separation induced at elevated temperatures. The observed photo‐stabilizing effect on active layer morphology is quite independent on the polymer and is attributed to light‐induced dimerization of the fullerene. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1209–1214 相似文献