全文获取类型
收费全文 | 7082篇 |
免费 | 189篇 |
国内免费 | 51篇 |
专业分类
化学 | 4507篇 |
晶体学 | 51篇 |
力学 | 235篇 |
数学 | 1389篇 |
物理学 | 1140篇 |
出版年
2022年 | 61篇 |
2021年 | 67篇 |
2020年 | 90篇 |
2019年 | 82篇 |
2018年 | 73篇 |
2017年 | 55篇 |
2016年 | 117篇 |
2015年 | 143篇 |
2014年 | 153篇 |
2013年 | 374篇 |
2012年 | 344篇 |
2011年 | 395篇 |
2010年 | 259篇 |
2009年 | 242篇 |
2008年 | 344篇 |
2007年 | 375篇 |
2006年 | 355篇 |
2005年 | 320篇 |
2004年 | 307篇 |
2003年 | 249篇 |
2002年 | 241篇 |
2001年 | 119篇 |
2000年 | 103篇 |
1999年 | 113篇 |
1998年 | 91篇 |
1997年 | 77篇 |
1996年 | 101篇 |
1995年 | 79篇 |
1994年 | 91篇 |
1993年 | 103篇 |
1992年 | 84篇 |
1991年 | 55篇 |
1990年 | 89篇 |
1989年 | 67篇 |
1988年 | 63篇 |
1987年 | 65篇 |
1986年 | 61篇 |
1985年 | 89篇 |
1984年 | 92篇 |
1983年 | 65篇 |
1982年 | 101篇 |
1981年 | 91篇 |
1980年 | 108篇 |
1979年 | 87篇 |
1978年 | 94篇 |
1977年 | 86篇 |
1976年 | 86篇 |
1975年 | 64篇 |
1974年 | 49篇 |
1973年 | 72篇 |
排序方式: 共有7322条查询结果,搜索用时 15 毫秒
1.
Dr. Chenge Li Dr. Alison G. Tebo Marion Thauvin Marie-Aude Plamont Prof. Dr. Michel Volovitch Dr. Xavier Morin Prof. Dr. Sophie Vriz Prof. Dr. Arnaud Gautier 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18073-18079
Far-red emitting fluorescent labels are highly desirable for spectral multiplexing and deep tissue imaging. Here, we describe the generation of frFAST (far-red Fluorescence Activating and absorption Shifting Tag), a 14-kDa monomeric protein that forms a bright far-red fluorescent assembly with (4-hydroxy-3-methoxy-phenyl)allylidene rhodanine (HPAR-3OM). As HPAR-3OM is essentially non-fluorescent in solution and in cells, frFAST can be imaged with high contrast in presence of free HPAR-3OM, which allowed the rapid and efficient imaging of frFAST fusions in live cells, zebrafish embryo/larvae, and chicken embryos. Beyond enabling the genetic encoding of far-red fluorescence, frFAST allowed the design of a far-red chemogenetic reporter of protein–protein interactions, demonstrating its great potential for the design of innovative far-red emitting biosensors. 相似文献
2.
3.
4.
5.
6.
Herman Winick 《Synchrotron Radiation News》2015,28(4):26-27
I am indebted to Karl Brown for suggesting that I invite Klaus, who I did not know at the time, to a workshop on wiggler magnets in March 1977. I recall Karl saying to me something like, “Herman, if you want someone who knows about magnets, you should invite Klaus Halbach.” Klaus came and even made a contribution about some aspects of the design of electromagnet wigglers, the only type of wigglers that had been considered to that time. However, it was at that workshop that Klaus got his introduction to synchrotron radiation, mostly by listening to talks by Albert Hofmann and Andy Sesler, who explained the marvelous properties of undulator magnets as radiation sources. Klaus filed this information in his long-term memory banks while working on other topics, particularly the design of permanent magnet quadrupoles for proton linacs. 相似文献
7.
Abstract
In this note, we consider a Frémond model of shape memory alloys. Let us imagine a piece of a shape memory alloy which is
fixed on one part of its boundary, and assume that forcing terms, e.g., heat sources and external stress on the remaining
part of its boundary, converge to some time-independent functions, in appropriate senses, as time goes to infinity. Under
the above assumption, we shall discuss the asymptotic stability for the dynamical system from the viewpoint of the global
attractor. More precisely, we generalize the paper [12] dealing with the one-dimensional case. First, we show the existence
of the global attractor for the limiting autonomous dynamical system; then we characterize the asymptotic stability for the
non-autonomous case by the limiting global attractor.
* Project supported by the MIUR-COFIN 2004 research program on “Mathematical Modelling and Analysis of Free Boundary Problems”. 相似文献
8.
Michel Hébert 《Archive for Mathematical Logic》1991,31(2):133-143
Summary We give a syntactic characterization of (finitary) theories whose categories of models are closed under the formation of connected limits (respectively the formation of pullbacks and substructures) in the category of all structures. They are also those theories whose consistent extensions by new atomic facts admit in each component an initial structure (respectively an initial term structure), and also thoseT for whichM(T) is locally finitely multi-presentable in a canonical way. We also show that these two properties of theories are nonuniform. 相似文献
9.
Constraint Programming and Operations Research: Comments from an Operations Researcher 总被引:4,自引:0,他引:4
Michel Gendreau 《Journal of Heuristics》2002,8(1):19-24
This paper relates the author's personal experience with constraint programming and gives a personal assessment of the relationships between constraint programming and operations research. 相似文献
10.
Franois Lavaud Michel Fontanille Yves Gnanou 《Journal of polymer science. Part A, Polymer chemistry》2004,42(19):4964-4975
Studies on the anionic polymerization of methyl methacrylate in tetrahydrofuran and in the presence of sparteine have revealed a beneficial effect due to this additive, resulting in a decrease in the extent of termination. Better control of the definition of the polymers formed can thus be achieved in the presence of this additive. On the other hand, macromolecular engineering requires a range of active species concentrations lower than 10?3 mol L?1 and particularly the synthesis of polymers of high molar masses. For a better understanding of the mechanism of chain growth under such concentration conditions, the kinetics of polymerization have been investigated with a technique based on adiabatic calorimetry. Sparteine has been found to lack sufficient cation‐binding power to prevent the propagating enolate ion pairs from aggregating. The rate constant of propagation of nonaggregated species has been estimated, as well as the aggregation constant of equilibrium. For very low initiator concentrations, termination reactions have been shown to profoundly alter the control of the polymerization and to prevent a quantitative monomer conversion. Theoretical maximal conversions have been calculated from kinetic data and compare well with the experimental values. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4964–4975, 2004 相似文献