全文获取类型
收费全文 | 652篇 |
免费 | 26篇 |
国内免费 | 3篇 |
专业分类
化学 | 391篇 |
晶体学 | 1篇 |
力学 | 31篇 |
数学 | 170篇 |
物理学 | 88篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 18篇 |
2021年 | 28篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 8篇 |
2017年 | 15篇 |
2016年 | 24篇 |
2015年 | 23篇 |
2014年 | 27篇 |
2013年 | 28篇 |
2012年 | 51篇 |
2011年 | 49篇 |
2010年 | 51篇 |
2009年 | 37篇 |
2008年 | 35篇 |
2007年 | 48篇 |
2006年 | 34篇 |
2005年 | 20篇 |
2004年 | 30篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有681条查询结果,搜索用时 15 毫秒
61.
Christos Kokkinos Anastasios Economou Ioannis Raptis Thanasis Speliotis 《Electrochemistry communications》2009,11(2):250-253
This work describes a novel type of antimony electrode for adsorptive stripping voltammetry (AdSV). The electrode was microfabricated by coating a silicon chip with a thin antimony-film by means of sputtering and the active area of the electrode was defined by photolithography. The resulting antimony-film electrodes (SbFEs) were characterized by optical and electrochemical techniques. The sensors were tested for the detection of low concentrations of Ni(II) by AdSV in the presence of dimethylglyoxime. Well-formed stripping peaks and a linear dependence of the stripping peak current on the Ni(II) concentration were observed on the microfabricated SbFEs while comparative measurements attempted with electroplated SbFEs were unsuccessful. Utilizing thin-film technology for the formation of the antimony-film extends the scope of these devices as mercury-free sensors in AdSV. 相似文献
62.
Per-Olof Fjällström Jyrki Katajainen Christos Levcopoulos Ola Petersson 《BIT Numerical Mathematics》1990,30(3):378-384
We present a parallel algorithm for finding the convex hull of a sorted set of points in the plane. Our algorithm runs inO(logn/log logn) time usingO(n log logn/logn) processors in theCommon crcw pram computational model, which is shown to be time and cost optimal. The algorithm is based onn
1/3 divide-and-conquer and uses a simple pointer-based data structure.Part of this work was done when the last three authors were at the Department of Computer and Information Science, Linköping University. The research of the second author was supported by the Academy of Finland. 相似文献
63.
Christos M. Tsoumanis 《Talanta》2010,82(2):575-358
A field flow approach for the in situ monitoring of wastewater quality is developed and assessed in this work, based on a combination of methods employing deconvolution of molecular absorption spectra and in situ/on-line analysis of wastewater effluent of various origin. The approach involves in situ immersion probes to monitor basic physicochemical parameters followed by UV spectrum deconvolution in order to provide a rapid estimate of organic matter, suspended solids and nitrate and on-line analysis of phosphates in a fully automated setup. The collected data are then treated with a series of supervised pattern recognition techniques in order to classify wastewater effluent according to their origin in three major categories namely municipal, industrial and hospital. The results suggest that the method affords a good approximation of realistic concentrations, as determined by reference methods, while it affords a good classification among various wastewater effluents of different origin. In that manner, the method enables a rapid inference of treated wastewater quality and a robust assessment of treatment process state, especially with regards to violations of effluent quality parameters. 相似文献
64.
Ilias Papasarantos Persefoni Klimentzou Vassiliki Koutrafouri Maria Anagnostouli Christos Zikos Maria Paravatou-Petsotas Evangelia Livaniou 《Applied biochemistry and biotechnology》2010,162(1):221-232
A biotin derivative, namely biotin–aminocaproic acid–lysine (BAL), was synthesized with solid-phase chemistry, conjugated
to a carrier-protein, and used for rabbit immunization. The aminocaproic acid–lysine “long-arm” was used in order to project
the biotin-hapten above the carrier-protein surface. Lysine was selected due to its Nε-amino group, through which BAL was conjugated to the carrier-protein. BAL was synthesized on a commercially available resin
with the Fmoc-solid-phase strategy; this has simplified the experimental procedure, overcome the need for intermediate purification
steps, and led to a final product of high purity, with high yield. The anti-BAL antibodies recognized free biotin, as shown
with an in-house-developed ELISA, in which biotin conjugated to a synthetic “lysine–dendrimer” was used to coat the ELISA
microwells. In immunocytology and Western-blot experiments, the anti-BAL antibodies led to similar results with those obtained
with streptavidin. Synthetic derivatives of hapten molecules that can be easily prepared with solid-phase chemistry, such
as BAL, may be used for the development of specific antibodies for the corresponding hapten. 相似文献
65.
Kefalidis CE Baudoin O Clot E 《Dalton transactions (Cambridge, England : 2003)》2010,39(43):10528-10535
DFT(B3PW91) calculations of the mechanism of the intramolecular C(sp(3))-H arylation of 2-bromo-tert-butylbenzene to form benzocyclobutene catalysed by Pd(PR(3)) (R = Me, (t)Bu) and a base (acetate, bicarbonate, carbonate) show that the preferred mechanism is highly dependent on the nature of the phosphine and the base used in the calculations. With the experimental reagents (P(t)Bu(3) and carbonate) the rate-determining step is C-H activation with the base coordinated trans to the C-H bond. An agostic interaction of a geminal C-H bond with respect to the bond to be cleaved induces a lowering of the activation barrier. 相似文献
66.
Christos Argirusis Francois JomardStefan F. Wagner Wolfgang MenesklouEllen Ivers-Tiffée 《Solid State Ionics》2011,192(1):9-11
For applications in high temperature fast conductometric gas sensors and oxygen membranes, several mixed conductors show promising features. In particular, acceptor-doped strontium titanate (STO) has been widely investigated for an application as a fast conductometric oxygen sensor. By a B-site substitution with 35% iron, the resulting ceramic solid solution SrTi0.65Fe0.35O3 (STF35) exhibits a temperature-independent conductivity, an ideal prerequisite for a gas sensor.In the presented study, the oxygen tracer exchange behavior and the tracer diffusion of dense ceramic STF35 bulks have been investigated in the temperature range between 600 and 900 °C by means of 18O2 tracer exchange experiments and subsequent secondary ion mass spectrometry (SIMS), resulting in the determination of k* and D* values, respectively.Furthermore, by coating the samples with a thin alkaline earth metal oxide layer (CaO), a significantly enhanced oxygen surface exchange reaction was observed. These findings are in good agreement with previous results on STO single crystals. 相似文献
67.
68.
Gerhard Post Jeffrey H. Kingston Samad Ahmadi Sophia Daskalaki Christos Gogos Jari Kyngas Cimmo Nurmi Nysret Musliu Nelishia Pillay Haroldo Santos Andrea Schaerf 《Annals of Operations Research》2014,218(1):295-301
We present the progress on the benchmarking project for high school timetabling that was introduced at PATAT 2008. In particular, we announce the High School Timetabling Archive XHSTT-2011 with 21 instances from 8 countries and an evaluator capable of checking the syntax of instances and evaluating the solutions. 相似文献
69.
Dimitrios G. Konstantinides Christos E. Kountzakis 《Journal of Theoretical Probability》2017,30(4):1726-1762
This paper relies on the application of Kantorovich functionals on quasi-interior points of the positive cone for certain classes of Orlicz spaces. Particularly we provide the asymptotic calculation of the ruin probability in the renewal risk model under heavy-tailed claims in the Orlicz spaces. This application assures the extension of classical asymptotic theory of regular variation. 相似文献
70.
Christos Tatakis Apostolos Thoma 《Journal of Combinatorial Theory, Series A》2011,118(5):1540-1548
The universal Gröbner basis of an ideal is a Gröbner basis with respect to all term orders simultaneously. We characterize in graph theoretical terms the elements of the universal Gröbner basis of the toric ideal of a graph. We also provide a new degree bound. Finally, we give examples of graphs for which the true degrees of their circuits are less than the degrees of some elements of the Graver basis. 相似文献