全文获取类型
收费全文 | 5161篇 |
免费 | 179篇 |
国内免费 | 32篇 |
专业分类
化学 | 2846篇 |
晶体学 | 54篇 |
力学 | 199篇 |
数学 | 1285篇 |
物理学 | 988篇 |
出版年
2023年 | 50篇 |
2022年 | 141篇 |
2021年 | 154篇 |
2020年 | 136篇 |
2019年 | 175篇 |
2018年 | 171篇 |
2017年 | 167篇 |
2016年 | 219篇 |
2015年 | 163篇 |
2014年 | 230篇 |
2013年 | 365篇 |
2012年 | 351篇 |
2011年 | 370篇 |
2010年 | 202篇 |
2009年 | 212篇 |
2008年 | 256篇 |
2007年 | 225篇 |
2006年 | 167篇 |
2005年 | 148篇 |
2004年 | 145篇 |
2003年 | 108篇 |
2002年 | 103篇 |
2001年 | 85篇 |
2000年 | 63篇 |
1999年 | 40篇 |
1998年 | 35篇 |
1997年 | 45篇 |
1996年 | 55篇 |
1995年 | 49篇 |
1994年 | 35篇 |
1993年 | 46篇 |
1992年 | 38篇 |
1991年 | 41篇 |
1990年 | 34篇 |
1989年 | 29篇 |
1988年 | 31篇 |
1987年 | 41篇 |
1986年 | 44篇 |
1985年 | 38篇 |
1984年 | 29篇 |
1983年 | 28篇 |
1982年 | 36篇 |
1981年 | 34篇 |
1980年 | 28篇 |
1979年 | 40篇 |
1978年 | 34篇 |
1977年 | 26篇 |
1976年 | 27篇 |
1975年 | 22篇 |
1974年 | 19篇 |
排序方式: 共有5372条查询结果,搜索用时 0 毫秒
21.
Ammar R Ball RC Banerjee S Bhat PC Bosetti P Bromberg C Canough GE Coffin T Dershem TO Dixon RL Fenker HC Ganguli SN Gensch U Girtler P Goshaw AT Grard F Gurtu A Hamilton C Henri VP Hernandez JJ Hrubec J Iori M Jones LW Kuhn D Knauss D Leedom ID Legros P Lemonne J Leutz H Liu X Malhotra PK Marraffino JM Mendez GE Miller R Naumann T Nguyen A Nowak H Pilette P Poirier J Poppleton A Raghavan R Rasner K Reucroft S Robertson WJ Roe BP Roth A Senko M Struczinski W Subramanian A Touboul MC Vonck B 《Physical review letters》1988,61(19):2185-2188
22.
K. D. Duch M. Heel H. Kalinowsky F. Kayser E. Klempt B. May O. Schreiber P. Weidenauer M. Ziegler D. Bailey S. Barlag J. M. Butler U. Gastaldi R. Landua C. Sabev W. Dahme F. Feld-Dahme U. Schaefer W. R. Wodrich J. C. Bizot B. Delcourt J. Jeanjean H. Nguyen E. G. Auld D. A. Axen K. L. Erdman B. Howard R. Howard B. L. White S. Ahmad M. Comyn G. M. Marshall G. Beer L. P. Robertson M. Botlo C. Laa H. Vonach C. Amsler M. Doser J. Riedlberger U. Straumann P. Truöl ASTERIX Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,45(2):223-234
Antiproton-proton annihilation at rest in a gaseous H2 target at NTP into the final state π+ π? K ± π? (K 0) with an undetectedK 0 or \(\bar K^0 \) has been investigated. We observe theE(1420) resonance in the invariant mass spectrum (K 0)miss K ± π? with massM E =1413±8 MeV/c2 and widthГ E =62 ± 16MeV/c2 and find evidence for the production of thef 1(1285). The absolute branching ratio of \(\bar p\) p → π+ π? E 0,E 0 →K 0 L K ± π ? at (61±6)%P wave annihilation is (3.0±0.9)·10?4 of all annihilations. The observed suppression of theE production fromP wave with respect to theS wave together with some simple selection rules suggest that the quantum numbers of theE(1420) areJ pc=0?+ and not I++. 相似文献
23.
24.
Bao Gia Nguyen 《Journal of statistical physics》1987,49(1-2):235-243
A study is made of the gap exponents for percolation processes with the triangle condition in the subcritical region. It is show that the gaps are given by
t
=2 fort=2, 3,. Scaling theory predicts thatP
p
(¦C
0¦S(p))–(p
c
–p) andE
p
(1/¦C
0¦; ¦C
0¦S(p))–(p
c
–p)3, whereS(p) is the typical cluster size. It is found that (p
c
–p)P
p
(|C
0S(p)
1–)(p
c
–p)1–2 and (p
c
–p)3E
p
(1/|C
0|;|C
0|S(p)
1–))(p
c
–p)3–4. 相似文献
25.
26.
27.
28.
The design of a supramolecular allosteric catalyst system for catalytic signal amplification and detection is presented. The catalyst was switched "on" by the introduction of an analyte that also behaves as an allosteric activator. Concentrations of Cl- ions as low as 800 nM were catalytically amplified and detected. The signal was transduced via a pH-sensitive fluorescent probe and observed visually using a laboratory, handheld UV lamp and by spectrophotometry. Furthermore, the allosteric effect was quantified using gas chromatography for a range of Cl- concentrations. This three-part detection scheme involving analyte binding, allosteric catalyst activation, and signal transduction represents a new approach to small-molecule detection. 相似文献
29.
A series of chemoselective polymers had been designed and synthesized to enhance the sorption properties of polymer coated chemical sensors for polynitroaromatic analytes. To evaluate the effectiveness of the chemoselective coatings, a polynitroaromatic vapor test bed was utilized to challenge polymer coated surface acoustic wave (SAW) devices with different explosive vapors. Dinitrotoluene detection limits were determined to be in the <100 parts per trillion ranges. ATR-FTIR studies were used to determine the nature of the polymer-polynitroaromatic analyte interactions, and confirm the presence of hydrogen-bonding between polymer pendant groups and the nitro functional groups of polynitroaromatic explosive materials. 相似文献
30.
Beyer RL Hoang HN Appleton TG Fairlie DP 《Journal of the American Chemical Society》2004,126(46):15096-15105
Short peptides corresponding to two to four alpha-helical turns of proteins are not thermodynamically stable helices in water. Unstructured octapeptide Ac-His1-Ala2-Ala3-His4-His5-Glu6-Leu7-His8-NH(2) (1) reacts with two [Pd((15)NH(2)(CH(2))(2)(15)NH(2))(NO(3))(2)] in water to form a kinetically stable intermediate, [[Pden](2)[(1,4)(5,8)-peptide]](2), in which two 19-membered metallocyclic rings stabilize two peptide turns. Slow subsequent folding to a thermodynamically more stable two-turn alpha-helix drives the equilibrium to [[Pden](2)[(1,5)(4,8)-peptide]] (3), featuring two 22-membered rings. This transformation from unstructured peptide via turns to an alpha-helix suggests that metal clips might be useful probes for investigating peptide folding. 相似文献