全文获取类型
收费全文 | 307篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
化学 | 149篇 |
晶体学 | 2篇 |
力学 | 12篇 |
数学 | 51篇 |
物理学 | 100篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 24篇 |
2012年 | 7篇 |
2011年 | 16篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 14篇 |
2007年 | 11篇 |
2006年 | 18篇 |
2005年 | 7篇 |
2004年 | 14篇 |
2003年 | 5篇 |
2002年 | 13篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1960年 | 1篇 |
1939年 | 2篇 |
1938年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 37 毫秒
1.
Sunanda Banerjee Rohini M Godbole Sreerup Raychaudhuri Ben Allanach Sunanda Banerjee Satyaki Bhattacharyya Debajyoti Choudhury Siba Prasad Das Anindya Datta Rohini M Godbole Monoranjan Guchait Sabine Kraml Gobinda Majumdar David Miller Margarete Mühlleitner Nobuchika Okada Maxim Perelstein Santosh K Rai Sreerup Raychaudhuri Saurabh D Rindani DP Roy K Sridhar Rishikesh Vaidya D Zeppenfeld 《Pramana》2006,67(4):617-637
This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology
(WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these
problems by the subgroups formed during the workshop is included in this report. 相似文献
2.
M K Parida Nita Sinha B Adhikary B Allanach A Alok K S Babu B Brahmachari D Choudhury E J Chun P K Das A Ghosal D Hitlin W S Hou S Kumar H N Li E Ma S K Majee G Majumdar B Mishra G Mohanty S Nandi H Pas M K Parida S D Rindani J P Saha N Sahu Y Sakai S Sen C Sharma C D Sharma S Shalgar N N Singh S Uma Sankar N Sinha R Sinha F Simonetto R Srikanth R Vaidya 《Pramana》2006,67(5):849-860
This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been
mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions
carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently. 相似文献
3.
Vikas V. Vaidya Santosh M. Yetal Shikha M. N. Roy Noel A. Gomes Santosh S. Joshi 《Chromatographia》2007,66(11-12):925-928
A rapid, sensitive and specific method to quantify pregabalin in human plasma using metaxalone as the internal standard is described. Sample preparation involved simple protein precipitation by using acetronitrile as solvent. The extract was analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (LC-MS–MS). Chromatography was performed isocratically on Thermo Hypurity C18 5 μm analytical column, (50 mm × 4.6 mm i.d.). The assay of pegabalin was linear calibration curve over the range 10.000–10000.000 ng mL?1. The lower limit of quantification was 10.000 ng mL?1 in plasma. The method was successfully applied to the bioequivalence study of pregabalin capsules (150.0 mg) administered as a single oral dose. 相似文献
4.
A new acyl anion addition reaction between acylsilanes and alpha,beta-unsaturated conjugate acceptors promoted by a nucleophilic organic catalyst has been disclosed. The 1,4-dicarbonyl products produced in this reaction are highly useful synthons. Neutral carbenes (or zwitterions) generated in situ from commercial thiazolium salts are used as effective catalysts for the reaction which is in contrast to established anionic catalysts typically employed to promote the required Brook rearrangement (1,2-silyl shift from carbon to oxygen) involved in the reported reaction. This process successfully utilizes acylsilanes as tunable acyl anion progenitors and is tolerant of a wide range of structural diversity on the acylsilane or the conjugate acceptor. 相似文献
5.
Kamat R. V. Sawant R. M. Mhatre H. R. Chaudhuri N. K. Vaidya V. N. 《Journal of Radioanalytical and Nuclear Chemistry》1998,238(1-2):33-41
pH titration curves generated by slow addition of alkali to solutions containing varying concentrations of uranyl nitrate
and nitric acid were studied using an autotitrator linked to a personal computer. A procedure with multiple choice of equations
has been developed for the estimation of free acid, nitrate and uranium in pure uranyl nitrate solution by a single titration.
The technique provides a simple single-step method with required accuracy and precision for the simultaneous estimation of
the three quantities in the uranyl nitrate feed solution of the sol-gel process for making UO3 microspheres. The relative standard deviations in the determination of uranium and nitrate were ±0.82% and ±1.52%, respectively,
in 15 determinations. 相似文献
6.
Pravin M. Vaidya 《Mathematical Programming》1996,73(3):291-341
Let
be a convex set for which there is an oracle with the following property. Given any pointz∈ℝ
n
the oracle returns a “Yes” ifz∈S; whereas ifz∉S then the oracle returns a “No” together with a hyperplane that separatesz fromS. The feasibility problem is the problem of finding a point inS; the convex optimization problem is the problem of minimizing a convex function overS. We present a new algorithm for the feasibility problem. The notion of a volumetric center of a polytope and a related ellipsoid
of maximum volume inscribable in the polytope are central to the algorithm. Our algorithm has a significantly better global
convergence rate and time complexity than the ellipsoid algorithm. The algorithm for the feasibility problem easily adapts
to the convex optimization problem. 相似文献
7.
P. C. Vaidya 《General Relativity and Gravitation》1978,9(9):801-807
The metric for the standard static Einstein model of the universe can be expressed in coordinates for which a congruence of spacelike world lines of the model will be twisting. A method of shifting the twist has been devised by which the twist on spacelike world lines is shifted onto the timelike world lines. The model universe then becomes Gödel's model. A combined Einstein-Gödel model containing a parameter is obtained. Switching from +1 to –1 will effect the shift of twist in the world lines and lead from the Einstein model to the Gödel model. 相似文献
8.
A DTA apparatus has been built to examine some of the errors neglected in present quantitative DTA. The heat transfer characteristics within DTA systems were found to limit in situ measurements of powder thermal conductivity. It was also demonstrated that the negligence of heat lost to the DTA block from the sample cell during an exothermic reaction and heat gained from the DTA block by the sample cell during endothermic reactions lead to large errors in quantitative estimations. A modified double differential thermocouple DTA was designed to take these heat losses into account. The apparatus was calibrated with CaCO3 and kaolinite endotherms and the kaolinite exotherm and tested on the SrCO3 rhombic trigonal inversion endotherm. The result was found to be in good agreement with accepted literature values.
Zusammenfassung Ein DTA-Apparatur wurde gebaut um einige in der gegenwärtig üblichen quantitativen DTA vernachlässigte Fehler zu prüfen. Es wurde gefunden, daß die Wärmeübertragungscharakteristika in DTA-Systemen die in situ Messungen der Wärmeleitfähigkeit von Pulvern begrenzen. Es wurde ebenfalls gezeigt, daß die Vernachlässigung von Wärmeverlusten der Probezelle an den DTA-Block bei exothermen Reaktionen und vom Wärmegewinn der Probezelle vom DTA-Block bei endothermen Reaktionen zu bedeutenden Fehlern in den quantitativen Bestimmungen führt. Ein DTA-Gerät mit doppeltem Differentialthermoelement wurde entworfen um diese Wärmeverluste zu berücksichtigen. Der Apparat wurde mittels der endothermen Reaktionen von CaCO3 und Kaolinit, bzw. mittels der exothermen Reaktion von Kaolinit geeicht und an der Inversion von rhombischem zu trigonalem SrCO3 erprobt.
Résumé On a réalisé un appareil ATD pour étudier certaines erreurs négligées jusqu'à présent en ATD quantitative. On a trouvé ainsi que les caractéristiques du transfert de chaleur limitent la mesure in situ de la conductivité thermique des poudres. On montre également que le fait de négliger les échanges de chaleur entre la cellule renfermant l'échantillon et le bloc ATD (pertes ou gains de chaleur suivant que les réactions sont exothermiques ou endothermiques) conduit à des erreurs considérables dans les dosages. Un double thermocouple différentiel a été conçu pour tenir compte de ces pertes. L'étalonnage de l'appareil a été ré alisé à l'aide des réactions endothermiques de CaCO3 et de la kaolinite et contrôlé avec la transition endothermique de SrCO3 (rhomboédrique-trigonal).
DTA , DTA. , DTA . , , DTA DTA . , . CaCO3 SrCO3.相似文献
9.
[reaction: see text] The hydroxy-directed reduction of 1,2-dehydropiperidines with the "ate" complex of DIBAL-H and n-BuLi affords functionalized trans-2,6-disubstituted piperidines. This methodology was employed in the asymmetric synthesis of the quinolizidine alkaloid (-)-lasubine I. 相似文献
10.