全文获取类型
收费全文 | 2101篇 |
免费 | 72篇 |
国内免费 | 6篇 |
专业分类
化学 | 1483篇 |
晶体学 | 16篇 |
力学 | 42篇 |
数学 | 288篇 |
物理学 | 350篇 |
出版年
2022年 | 30篇 |
2021年 | 41篇 |
2020年 | 36篇 |
2019年 | 27篇 |
2018年 | 35篇 |
2017年 | 27篇 |
2016年 | 64篇 |
2015年 | 40篇 |
2014年 | 51篇 |
2013年 | 100篇 |
2012年 | 91篇 |
2011年 | 97篇 |
2010年 | 65篇 |
2009年 | 57篇 |
2008年 | 104篇 |
2007年 | 82篇 |
2006年 | 80篇 |
2005年 | 97篇 |
2004年 | 62篇 |
2003年 | 66篇 |
2002年 | 62篇 |
2001年 | 30篇 |
2000年 | 23篇 |
1999年 | 12篇 |
1998年 | 17篇 |
1997年 | 23篇 |
1996年 | 35篇 |
1995年 | 21篇 |
1994年 | 16篇 |
1993年 | 33篇 |
1992年 | 17篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1988年 | 14篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 20篇 |
1984年 | 33篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 18篇 |
1980年 | 12篇 |
1979年 | 18篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 18篇 |
1975年 | 16篇 |
1973年 | 12篇 |
1966年 | 11篇 |
1901年 | 11篇 |
排序方式: 共有2179条查询结果,搜索用时 602 毫秒
1.
2.
Mejía Hugo Fernando Giraldo Jiménez-Piqué Emilio Valdés Matías Procaccini Raúl Pellice Sergio 《Journal of Solid State Electrochemistry》2020,24(10):2451-2460
Journal of Solid State Electrochemistry - A novel material was developed using sol-gel chemistry and an environmental-friendly grafting process of clay nanoparticles. In a previous work of our... 相似文献
3.
Viviane Van Hoof Hugo Cluckers Vera Verhaeghe An Hennebel Marleen Truyens Edith Van Loock Pierre Rombouts Dirk Maes Jan Van Elven Katrien Lesage Mark Flothmann Lieve Nijs Filip Colpaert Werner Vercammen Dominique Bolain 《Accreditation and quality assurance》2004,10(1-2):55-59
In response to a change of the Belgian National Directives whereby hospital laboratories became responsible for all point-of-care testing (POCT) performed within hospital walls a standardized and automated POC glucose-testing system was implemented in our hospital. The system consists of 50 AccuCheck Inform instruments (Roche Diagnostics, Vilvoorde, Belgium), 50 docking stations, a DataCare Server, and connections to the medical laboratory information system (MOLIS, Sysmex, Barchon, Belgium) and to the hospital information system. Implementation involved many parties and extensive preparation and communication. Key issues were bar-coded patient and user identification, training, and responsibilities. One year after the hospital wide implementation of this system the quality of POC glucose testing has significantly increased, thereby improving patient safety. This study describes a stepwise change over involving the medical laboratory and with a focus on hands-on quality.Presented at the ninth conference on Quality in the Spotlight, 18–19 March 2004, Antwerp, Belgium. 相似文献
4.
After having introduced by ion implantation 57Fe to a local concentration of 7 at% into Co6Ag94, we observed it by conversion electron Mössbauer spectroscopy in the as-prepared state and after isochronal annealing. A superferromagnetic state is inferred, which is correlated with the ordering of the magnetic moments on the Fe clusters through chain-like or dendritic Co/Fe linear structures. The magnetic moment disordering temperature lies above 473 K. 相似文献
5.
In this article, we show how to construct pairs of orthogonal pandiagonal Latin squares and panmagic squares from certain types of modular n‐queens solutions. We prove that when these modular n‐queens solutions are symmetric, the panmagic squares thus constructed will be associative, where for an n × n associative magic square A = (aij), for all i and j it holds that aij + an?i?1,n?j?1 = c for a fixed c. We further show how to construct orthogonal Latin squares whose modular difference diagonals are Latin from any modular n‐queens solution. As well, we analyze constructing orthogonal pandiagonal Latin squares from particular classes of non‐linear modular n‐queens solutions. These pandiagonal Latin squares are not row cyclic, giving a partial solution to a problem of Hedayat. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 221–234, 2007 相似文献
6.
The existence of sparse pseudorandom distributions is proved. These are probability distributions concentrated in a very small set of strings, yet it is infeasible for any polynomial-time algorithm to distinguish between truly random coins and coins selected according to these distributions. It is shown that such distributions can be generated by (nonpolynomial) probabilistic algorithms, while probabilistic polynomial-time algorithms cannot even approximate all the pseudorandom distributions. Moreover, we show the existence of evasive pseudorandom distributions which are not only sparse, but also have the property that no polynomial-time algorithm may find an element in their support, except for a negligible probability. All these results are proved independently of any intractability assumption. 相似文献
7.
Hugo Schiff 《Fresenius' Journal of Analytical Chemistry》1911,50(11):723
Ohne Zusammenfassung 相似文献
8.
9.
10.
Atiya MS Chiang I Frank JS Haggerty JS Ito MM Kycia TF Li KK Littenberg LS Stevens A Strand RC Louis WC Akerib DS Marlow DR Meyers PD Selen MA Shoemaker FC Smith AJ Azuelos G Blackmore EW Bryman DA Felawka L Kitching P Kuno Y Macdonald JA Numao T Padley P Poutissou J Poutissou R Roy J 《Physical review letters》1990,65(1):21-24