全文获取类型
收费全文 | 1754篇 |
免费 | 73篇 |
国内免费 | 4篇 |
专业分类
化学 | 1472篇 |
晶体学 | 8篇 |
力学 | 10篇 |
数学 | 135篇 |
物理学 | 206篇 |
出版年
2023年 | 20篇 |
2022年 | 22篇 |
2021年 | 49篇 |
2020年 | 46篇 |
2019年 | 29篇 |
2018年 | 37篇 |
2017年 | 33篇 |
2016年 | 69篇 |
2015年 | 67篇 |
2014年 | 81篇 |
2013年 | 108篇 |
2012年 | 111篇 |
2011年 | 116篇 |
2010年 | 73篇 |
2009年 | 67篇 |
2008年 | 115篇 |
2007年 | 106篇 |
2006年 | 101篇 |
2005年 | 93篇 |
2004年 | 66篇 |
2003年 | 51篇 |
2002年 | 63篇 |
2001年 | 21篇 |
2000年 | 31篇 |
1999年 | 19篇 |
1998年 | 16篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 18篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1969年 | 3篇 |
1959年 | 2篇 |
1956年 | 6篇 |
排序方式: 共有1831条查询结果,搜索用时 281 毫秒
1.
Central European Journal of Operations Research - This paper deals with the dynamic efficiency analysis based on Data Envelopment Analysis (DEA) models. Our aim is to formulate new dynamic DEA... 相似文献
2.
3.
A protocol to correct for intra‐ and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line 下载免费PDF全文
4.
5.
Wolfram Bremser Roland Becker Heinrich Kipphardt Petra Lehnik-Habrink Ulrich Panne Antje Töpfer 《Accreditation and quality assurance》2006,11(10):489-495
ISO Guide 35 deals with RM stability issues and scrutinizes the evaluation of stability testing results under the assumption that either there is no trend at all (a rather rare situation), or any observed deterministic change is insignificant and thus can be neglected. However, market demands for reliable reference materials are obviously not limited to stable or at least seemingly stable materials. In many analytical applications, analytes and measurands under consideration are known, or at least suspected, to be unstable on time scales that may vary widely from measurand to measurand. The Federal Institute for Materials Research and Testing (BAM) has developed (and successfully uses) an integrated approach in its certification practice. The approach is based on an initial stability study and subsequent post-certification monitoring. Data evaluation is model-based and takes advantage of all information collected in the stability testing scheme(s). It thus allows one to deal with any kind of instability observed, to assess limiting time intervals at any stress condition in the range tested, to estimate a final expiry date for materials with detected instabilities or the maximum admissible re-testing interval for seemingly stable materials, and to assess maximum admissible stress loads during delivery of the material to the customer. The article describes (and exemplifies) typical study layout, the model selection, and the integrated data assessment. 相似文献
6.
P. Kolář 《Czechoslovak Journal of Physics》1989,39(11):1317-1320
Conclusions The sets (3) and (4) of condensates have been compared using the QCD sum rules (2) with indefinite weight functions. A bad matching between both sets of condensates and experimental data has been obtained. The standard values (3) appear to be closer to data but some increase ofQ is necessary to improve the agreement. Only higher values ofm
0
2
could change the results of this analysis. It is interesting that negative values ofm
0
2
considerably improve the agreement with data; note that this quantity cannot be determined with a sufficient accuracy. We conclude that the QCD sum rules (2) cannot definitely determine a privileged set of condensates.Dedicated to Academician Václav Votruba on the occasion of his eightieth birthday. 相似文献
7.
A computer construction of the Monster is used to prove thatPSL(2, 59) is a subgroup of the Monster. 相似文献
8.
Botjan Japelj Simon Re
nik Petra ebaek Branko Stanovnik Jurij Svete 《Journal of heterocyclic chemistry》2005,42(6):1167-1173
A series of alkyl l‐heteroaryl‐1H‐1,2,3‐triazole‐4‐carboxylates 6a‐u were synthesised in four steps from methyl (Z)‐2‐benzyloxycarbonylarmino‐3‐(dimethylamino)prop‐2‐enoate ( 1 ) and heterocyclic amines 2a‐s. Triazoles 6a‐o were tested against antimycobacterial activity. For the most active compound, n‐pentyl 1‐(6‐phenylpyridazin‐3‐yl)‐1H‐1,2,3‐triazole‐4‐carboxylate ( 6n ), minimum inhibitory concentration 3.13 μg/ml was determined. 相似文献
9.
10.
G. R. Kosmambetova P. E. Strizhak É. M. Moroz T. E. Konstantinova A. V. Gural’skii V. P. Kol’ko V. I. Gritsenko I. A. Danilenko O. A. Gorban 《Theoretical and Experimental Chemistry》2007,43(2):102-107
The morphological and catalytic properties of samples of nanomeric zirconium dioxide, stabilized with yttrium oxide, manufactured
via the effect of a UHF field during the process of drying precipitated zirconium hydroxide and calcination at temperatures
from 300 to 1000 °C, were studied. It was shown that the highest activity in the oxidation of CO occurred with 40 nm particles
of zirconium dioxide prepared at 1000 °C.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 2, pp. 96–101, March–April, 2007. 相似文献