全文获取类型
收费全文 | 8071篇 |
免费 | 238篇 |
国内免费 | 37篇 |
专业分类
化学 | 5192篇 |
晶体学 | 58篇 |
力学 | 111篇 |
综合类 | 16篇 |
数学 | 1136篇 |
物理学 | 1247篇 |
无线电 | 586篇 |
出版年
2021年 | 67篇 |
2020年 | 78篇 |
2019年 | 101篇 |
2018年 | 77篇 |
2017年 | 66篇 |
2016年 | 145篇 |
2015年 | 123篇 |
2014年 | 151篇 |
2013年 | 308篇 |
2012年 | 331篇 |
2011年 | 361篇 |
2010年 | 204篇 |
2009年 | 223篇 |
2008年 | 375篇 |
2007年 | 334篇 |
2006年 | 340篇 |
2005年 | 341篇 |
2004年 | 310篇 |
2003年 | 260篇 |
2002年 | 260篇 |
2001年 | 135篇 |
2000年 | 163篇 |
1999年 | 124篇 |
1998年 | 117篇 |
1997年 | 100篇 |
1996年 | 124篇 |
1995年 | 147篇 |
1994年 | 129篇 |
1993年 | 90篇 |
1992年 | 97篇 |
1991年 | 92篇 |
1990年 | 98篇 |
1989年 | 104篇 |
1988年 | 106篇 |
1987年 | 89篇 |
1986年 | 81篇 |
1985年 | 134篇 |
1984年 | 97篇 |
1983年 | 113篇 |
1982年 | 130篇 |
1981年 | 115篇 |
1980年 | 105篇 |
1979年 | 108篇 |
1978年 | 84篇 |
1977年 | 84篇 |
1976年 | 73篇 |
1975年 | 68篇 |
1974年 | 80篇 |
1973年 | 73篇 |
1971年 | 56篇 |
排序方式: 共有8346条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Werner Leißner 《Results in Mathematics》1991,20(1-2):530-537
5.
We relate the Schramm–Loewner Evolution processes (SLE) to highest-weight representations of the Virasoro Algebra. The restriction properties of SLE that have been recently derived in [19] play a crucial role. In this setup, various considerations from conformal field theory can be interpreted and reformulated via SLE. This enables one to make a concrete link between the two-dimensional discrete critical systems from statistical physics and conformal field theory. To cite this article: R. Friedrich, W. Werner, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 947–952. 相似文献
6.
Electron beam induced quantitative X-ray mapping has become a very useful characterisation tool for determining the elemental
distribution in materials, whether using energy dispersive spectroscopy or wavelength dispersive spectroscopy. The X-ray intensity
distributions of the elements from an X-ray map allow us to generate two dimensional and ternary scatter diagrams thus converting
spatial information into concentration dimensions, which is an important tool for displaying the spatial relationships of
elements or correlated elements (phases) in materials. To best understand how to use this tool, we need to understand the
production and features of the scatter diagram. The type of clustering observed in the scatter diagram, whether oval, linear
or spherical, can give the major and trace element distributions within phases as well as qualitative and quantitative phase
information. This paper demonstrates the generation of scatter diagrams, properties of scatter diagrams, interpretation of
scatter diagrams and the advantages of scatter diagrams through the use of examples. 相似文献
7.
8.
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
9.
Yoshiyuki Watabe Takuya Kondo Hiroe Imai Masatoshi Morita Nobuo Tanaka Jun Haginaka Ken Hosoya 《Analytical sciences》2004,20(1):133-137
A new high-performance liquid chromatography (HPLC) method has been developed to detect ultra-low concentrations of bisphenol-A (BPA) (below 1 ng/L (ppt)) using column switching electrochemical detection (ECD). The results were superior to those obtained from manual pretreatment procedure with membrane stationary phase. BPA is inherently ubiquitous in the environment, including tools and solvents used for its analysis; to obtain meaningful results, therefore, the concentration of the overall BPA contamination must be below the detection limit for BPA using the analytical system. Therefore, purified water for preparing the standard BPA solution must be filtered with a hydrophobic membrane to suppress BPA background levels of contamination. In addition, we investigated methods for effectively preserving environmental water containing BPA. The addition of a small amount of ethylenediaminetetraacetic acid (EDTA) provided good recovery even after overnight storage. By employing these precautionary measures and procedures to reduce BPA contamination from the analytical procedure, we could accurately determine l(-10) ppt of BPA in environmental water samples using a column switching HPLC system. 相似文献
10.
We examine certain special features exhibited by various classes of linear operators acting in a hereditarily indecomposable
Banach space. For instance, we show that the family of all Riesz operators in a H.I. space forms a closed, 2-sided ideal.
We also give further characterizations of the class of scalar-type spectral operators (to those already given in [16]). The
final section discusses some properties of the spectral maximal spaces of (necessarily decomposable) linear operators in such
spaces.
Conferenza tenuta il 16 settembre 1997
The support of the German Academic Exchange Scheme (DAAD) is gratefully acknowledged 相似文献