全文获取类型
收费全文 | 8378篇 |
免费 | 205篇 |
国内免费 | 18篇 |
专业分类
化学 | 5727篇 |
晶体学 | 50篇 |
力学 | 117篇 |
数学 | 1449篇 |
物理学 | 1258篇 |
出版年
2021年 | 60篇 |
2020年 | 67篇 |
2019年 | 76篇 |
2016年 | 161篇 |
2015年 | 121篇 |
2014年 | 154篇 |
2013年 | 251篇 |
2012年 | 277篇 |
2011年 | 327篇 |
2010年 | 195篇 |
2009年 | 188篇 |
2008年 | 283篇 |
2007年 | 275篇 |
2006年 | 276篇 |
2005年 | 232篇 |
2004年 | 264篇 |
2003年 | 211篇 |
2002年 | 212篇 |
2001年 | 138篇 |
2000年 | 167篇 |
1999年 | 125篇 |
1998年 | 128篇 |
1997年 | 105篇 |
1996年 | 124篇 |
1995年 | 165篇 |
1994年 | 139篇 |
1993年 | 113篇 |
1992年 | 121篇 |
1991年 | 123篇 |
1990年 | 102篇 |
1989年 | 134篇 |
1988年 | 128篇 |
1987年 | 107篇 |
1986年 | 103篇 |
1985年 | 152篇 |
1984年 | 113篇 |
1983年 | 139篇 |
1982年 | 140篇 |
1981年 | 118篇 |
1980年 | 123篇 |
1979年 | 127篇 |
1978年 | 103篇 |
1977年 | 112篇 |
1976年 | 90篇 |
1975年 | 79篇 |
1974年 | 87篇 |
1973年 | 88篇 |
1972年 | 59篇 |
1971年 | 75篇 |
1970年 | 56篇 |
排序方式: 共有8601条查询结果,搜索用时 15 毫秒
1.
Clemens G. Raab Georg Regensburger Jamal Hossein Poor 《Journal of Pure and Applied Algebra》2021,225(5):106564
A formal computation proving a new operator identity from known ones is, in principle, restricted by domains and codomains of linear operators involved, since not any two operators can be added or composed. Algebraically, identities can be modelled by noncommutative polynomials and such a formal computation proves that the polynomial corresponding to the new identity lies in the ideal generated by the polynomials corresponding to the known identities. In order to prove an operator identity, however, just proving membership of the polynomial in the ideal is not enough, since the ring of noncommutative polynomials ignores domains and codomains. We show that it suffices to additionally verify compatibility of this polynomial and of the generators of the ideal with the labelled quiver that encodes which polynomials can be realized as linear operators. Then, for every consistent representation of such a quiver in a linear category, there exists a computation in the category that proves the corresponding instance of the identity. Moreover, by assigning the same label to several edges of the quiver, the algebraic framework developed allows to model different versions of an operator by the same indeterminate in the noncommutative polynomials. 相似文献
2.
Robin F. Weitkamp Beate Neumann Hans‐Georg Stammler Berthold Hoge 《Angewandte Chemie (International ed. in English)》2020,59(14):5494-5499
We report on the first examples of isolated silanol–silanolate anions, obtained by utilizing weakly coordinating phosphazenium counterions. The silanolate anions were synthesized from the recently published phosphazenium hydroxide hydrate salt with siloxanes. The silanol–silanolate anions are postulated intermediates in the hydroxide‐mediated polymerization of aryl and alkyl siloxanes. The silanolate anions are strong nucleophiles because of the weakly coordinating character of the phosphazenium cation, which is perceptible in their activity in polysiloxane depolymerization. 相似文献
3.
4.
5.
Werner Leißner 《Results in Mathematics》1991,20(1-2):530-537
6.
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
7.
8.
9.
Georg von Georgievics 《Monatshefte für Chemie / Chemical Monthly》1885,6(1):754-759
Ohne ZusammenfassungDiese Untersuchung ist vor mehr als Jahresfrist infolge Eintrittes in die chemische Praxis abgebrochen worden. Äussere Verhältnisse machen die Vollendung der begonnenen Versuche auch weiterhin unmöglich und sehe ich mich desshalb veranlasst, meine Beobachtungen zu veröffentlichen. 相似文献
10.
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