全文获取类型
收费全文 | 527篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
化学 | 310篇 |
晶体学 | 4篇 |
力学 | 9篇 |
数学 | 67篇 |
物理学 | 168篇 |
出版年
2023年 | 3篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 21篇 |
2015年 | 21篇 |
2014年 | 12篇 |
2013年 | 28篇 |
2012年 | 32篇 |
2011年 | 32篇 |
2010年 | 26篇 |
2009年 | 18篇 |
2008年 | 21篇 |
2007年 | 40篇 |
2006年 | 22篇 |
2005年 | 35篇 |
2004年 | 22篇 |
2003年 | 15篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 22篇 |
1999年 | 18篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 15篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1977年 | 7篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有558条查询结果,搜索用时 15 毫秒
1.
On the basis of a plane-wave spectrum representation, the polarization features of a transverse quasimonochromatic non-paraxial field have been studied. A relationship has been established between the polarization characteristics in the near field and the coherence and symmetry properties of the beam in the far field. 相似文献
2.
3.
4.
Agüera A Pérez Estrada LA Ferrer I Thurman EM Malato S Fernández-Alba AR 《Journal of mass spectrometry : JMS》2005,40(7):908-915
Exact mass capabilities of time-of-flight (TOF) mass spectrometry along with other mass spectrometric techniques have been evaluated to elucidate a complete range of dichlofenac phototransformation products. Photolysis experiments with diclofenac in water under direct solar irradiation were performed to characterise the main phototransformation products generated and to determine their stability. Photolysis experiments were performed in both demineralised water and reconstructed standard freshwater. Samples were extracted before analysis by solid phase extraction (SPE) with Oasis HLB and MAX cartridges. Separation and identification of the transformation products were accomplished by the combined use of gas chromatography-mass spectrometry (GC/MS) and liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOFMS). Both techniques provided complementary information that enabled the identification of 13 phototransformation products. Six of them were identified by GC/MS through the structural information provided by the full scan mass spectra obtained under electron impact (EI) ionisation and the confirmation of the molecular mass provided by positive chemical ionisation (PCI) analyses. Accurate mass measurements obtained by LC/TOFMS provided the elucidation of seven polar transformation products. The low mass error observed (<2 ppm) enabled the assignment of highly probable empirical formulas as well as identification of a process dimerisation route. The photoproducts identified demonstrated that photolysis of diclofenac occurs by two main routes. One is the consequence of the initial photocyclisation of diclofenac into carbazole derivatives. The other route goes through the initial decarboxilation of diclofenac and further oxidation of the alkyl-chain, which are typical photolytic process reactions. The main photoproduct identified was 8-chloro-9H-carbazole-1yl-acetic acid. 相似文献
5.
6.
7.
IfA is a -algebra on setX, thenl
0
(X,A) is a barrelled space of class 0. IfA is an algebra, there are conditions which imply thatl
0
(X,A) is suprabarelled. Here, wheneverA is an algebra, we give conditions forl
0
(X,A) to be not barrelled which are related with the existence of non-trivial convergent sequences.Supported in part by DGICYT, project PB91-0407 and by the Institució Valenciana d'Estudis i Investigació, project 023. 相似文献
8.
9.
Alves GA Amato S Anjos JC Appel JA Astorga J Bracker SB Cremaldi LM Darling CL Dixon RL Errede D Fenker HC Gay C Green DR Halling AM Jedicke R Karchin PE Kwan S Leuking LH Mantsch PM de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A Passmore D Rafatian A dos Reis AC Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wallace A Wu Z 《Physical review D: Particles and fields》1994,49(9):R4317-R4320
10.
Alves GA Amato S Anjos JC Appel JA Astorga J Bracker SB Cremaldi LM Dagenhart WD Darling CL Dixon RL Errede D Fenker HC Gay C Green DR Jedicke R Karchin PE Kennedy C Kwan S Lueking LH de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A Passmore D Rafatian A dos Reis AC Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wallace A Wu Z 《Physical review letters》1996,77(12):2388-2391