全文获取类型
收费全文 | 5613篇 |
免费 | 313篇 |
国内免费 | 57篇 |
专业分类
化学 | 4156篇 |
晶体学 | 22篇 |
力学 | 99篇 |
综合类 | 1篇 |
数学 | 940篇 |
物理学 | 765篇 |
出版年
2023年 | 49篇 |
2022年 | 80篇 |
2021年 | 107篇 |
2020年 | 149篇 |
2019年 | 123篇 |
2018年 | 105篇 |
2017年 | 87篇 |
2016年 | 183篇 |
2015年 | 158篇 |
2014年 | 204篇 |
2013年 | 286篇 |
2012年 | 456篇 |
2011年 | 479篇 |
2010年 | 230篇 |
2009年 | 170篇 |
2008年 | 403篇 |
2007年 | 375篇 |
2006年 | 380篇 |
2005年 | 342篇 |
2004年 | 313篇 |
2003年 | 237篇 |
2002年 | 211篇 |
2001年 | 83篇 |
2000年 | 43篇 |
1999年 | 40篇 |
1998年 | 39篇 |
1997年 | 49篇 |
1996年 | 52篇 |
1995年 | 45篇 |
1994年 | 41篇 |
1993年 | 40篇 |
1992年 | 35篇 |
1991年 | 35篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 24篇 |
1987年 | 23篇 |
1986年 | 29篇 |
1985年 | 25篇 |
1984年 | 15篇 |
1983年 | 19篇 |
1982年 | 17篇 |
1981年 | 20篇 |
1980年 | 20篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 11篇 |
1971年 | 10篇 |
排序方式: 共有5983条查询结果,搜索用时 797 毫秒
71.
There is a need to develop broadly applicable, highly sensitive detection methods for microchip CE that do not require analyte derivatization. LIF is highly sensitive but typically requires analyte derivatization. Electrochemistry provides an alternative method for direct analyte detection; however, in its most common form, direct current (DC) amperometry, it is limited to a small number of easily oxidizable or reducible analytes. Pulsed amperometric detection (PAD) is an alternative waveform that can increase the number of electrochemically detectable analytes. Increasing sensitivity for electrochemical detection (EC) and PAD requires the isolation of detection current (nA) from the separation current (muA) in a process generally referred to as current decoupling. Here, we present the development of a simple integrated decoupler to improve sensitivity and its coupling with PAD. A Pd microwire is used as the cathode for decoupling and a second Au or Pt wire is used as the working electrode for either EC or PAD. The electrode system is easy to make, requiring no clean-room facilities or specialized metallization systems. Sensitive detection of a wide range of analytes is shown to be possible using this system. Using this system we were able to achieve detection limits as low as 5 nM for dopamine, 74 nM for glutathione, and 100 nM for glucose. 相似文献
72.
Abe K Abt I Ahn CJ Akagi T Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Dasu S 《Physical review letters》1995,74(9):1512-1516
73.
Abe K Abt I Ahn CJ Akagi T Allen NJ Ash WW Aston D Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Daoudi M 《Physical review D: Particles and fields》1995,52(7):4240-4244
74.
In this article we give an existence theorem for localized travelling wave solutions on one-dimensional lattices with Hamiltonian $$H = \sum\limits_{n \in \mathbb{Z}} {\left( {\tfrac{1}{2}p_n^2 + V(q_{n + 1} - q_n )} \right)} ,$$ whereV(·) is the potential energy due to nearest-neighbour interactions. Until now, apart from rare integrable lattices like the Toda latticeV(φ)=ab ?1(e ?bφ+bφ?1), the only evidence for existence of such solutions has been numerical. Our result in particular recovers existence of solitary waves in the Toda lattice, establishes for the first time existence of solitary waves in the (nonintegrable) cubic and quartic latticesV(φ)= 1/2φ 2 + 1/3aφ 3,V(φ) = 1/2φ 2 + 1/4bφ 4, thereby confirming the numerical findings in [1] and shedding new light on the recurrence phenomena in these systems observed first by Fermi, Pasta and Ulam [2], and shows that contrary to widespread belief, the presence of exact solitary waves is not a peculiarity of integrable systems, but “generic” in this class of nonlinear lattices. The approach presented here is new and quite general, and should also be applicable to other forms of lattice equations: the travelling waves are sought as minimisers of a naturally associated variational problem (obtained via Hamilton's principle), and existence of minimisers is then established using modern methods in the calculus of variations (the concentration-compactness principle of P.-L. Lions [3]). 相似文献
75.
76.
Abe K Abt I Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Dasu S De Sangro R De Simone P 《Physical review D: Particles and fields》1994,50(9):5580-5590
77.
Armstrong TA Bettoni D Bharadwaj V Biino C Borreani G Broemmelsiek D Buzzo A Calabrese R Ceccucci A Cester R Church M Dalpiaz P Dalpiaz PF Dimitroyannis D Fabbri M Fast J Gianoli A Ginsburg CM Gollwitzer K Govi G Hahn A Hasan M Hsueh S Lewis R Luppi E Macrí M Majewska AM Mandelkern M Marchetto F Marinelli M Marques J Marsh W Martini M Masuzawa M Menichetti E Migliori A Mussa R Palestini S Pallavicini M Passaggio S Pastrone N Patrignani C Peoples J Petrucci F Pia MG Pordes S Rapidis P Ray R 《Physical review D: Particles and fields》1996,54(11):7067-7070
78.
79.
Abe K Abt I Acton PD Agnew G Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Baranko G Bardon O Battiston R Bazarko AO Bean A Belcinski RJ Ben-David R Benvenuti AC Biasini M Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Carr J Cassell R Castaldi R Castro A Cavalli-Sforza M Chadwick GB Chen L Church E Claus R Cohn HO Coller JA Cook V Cotton R 《Physical review letters》1993,71(16):2528-2532
80.