全文获取类型
收费全文 | 557篇 |
免费 | 8篇 |
国内免费 | 9篇 |
专业分类
化学 | 281篇 |
晶体学 | 2篇 |
力学 | 11篇 |
数学 | 136篇 |
物理学 | 144篇 |
出版年
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 20篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 16篇 |
2002年 | 10篇 |
2001年 | 17篇 |
2000年 | 16篇 |
1999年 | 8篇 |
1998年 | 17篇 |
1997年 | 13篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 13篇 |
1993年 | 16篇 |
1992年 | 14篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 17篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1973年 | 10篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1968年 | 5篇 |
1967年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有574条查询结果,搜索用时 46 毫秒
491.
Alexander L. Rosenberg 《Communications in Mathematical Physics》1991,142(3):567-588
The left spectrum of a wide class of the algebras of skew differential operators is described. As a sequence, we determine and classify all the algebraically irreducible representations of the quantum Heisenberg algebra over an arbitrary field. 相似文献
492.
An explicit finite difference equation has been development for the solution of the convection-dispersion equation. This equation has been over the entire range of 2D/vΔx between zero and one, region where no completely satisfactory method has been previously available. No oscillations or numerical dispersion were observed in any of the solutions. 相似文献
493.
U. Beck K.H. Becks V. Burkert J. Drees B. Dresbach B. Gerhardt G. Knop H. Kolanoski M. Leenen K. Moser H. Müller Ch. Nietzel J. Päsler K. Rith M. Rosenberg R. Sauerwein E. Schlösser H.E. Stier 《Physics letters. [Part B]》1974,51(1):103-105
The reaction e? + p → e? + p + η has been studied in the region of the S11 (1535)-resonance by detecting the recoil proton in coincidence with the scattered electron. The reaction has been observed at three four-momentum transfers of the virtual photon: q2 = 0.2, 0.28 and 0.4 (GeV/c). First results of the differential cross section measurements are given and compared with quark model calculations. 相似文献
494.
495.
Ash WW Band HR Blume HT Camporesi T Chadwick GB Clearwater SH Coombes RW Delfino MC De Sangro R Fernandez E Ford WT Gettner MW Goderre GP Groom DE Heltsley BK Hurst RB Johnson JR Lau KH Lavine TL Lee HY Leedy RE Marini A Maruyama T Messner RL Moromisato JH Moss LJ Muller F Nelson HN Peruzzi I Piccolo M Prepost R Qi N Read AL Ritson DM Rosenberg LJ Shambroom WD Sleeman JC Smith JG Venuti JP von Goeler E Wald HB Weinstein R Wiser DE Zdarko RW 《Physical review letters》1985,54(23):2477-2480
496.
Ash WW Band HR Bloom ED Bosman M Camporesi T Chadwick GB Delfino MC De Sangro R Ford WT Gettner MW Goderre GP Godfrey GL Groom DE Hurst RB Johnson JR Lau KH Lavine TL Leedy RE Lippi I Maruyama T Messner RL Moromisato JH Moss LJ Muller F Nelson HN Peruzzi I Piccolo M Prepost R Pyrlik J Qi N Read AL Ritson DM Rosenberg LJ Shambroom WD Sleeman JC Smith JG Venuti JP Verdini PG von Goeler E Wald HB Weinstein R Wiser DE Zdarko RW 《Physical review letters》1987,58(7):640-643
497.
Supramolecular photolyses of 3-chloro-3-phenyl-3H-diazirine (8) were performed within cyclodextrin (CyD) hosts to determine whether these toroidal inclusion compounds could alter the reactivity of the ensuing carbene reaction intermediate, chloro(phenyl)carbene (9). Remarkably, no intramolecular products stemming from carbene 9 could be detected. Instead, modified CyDs were formed via so-called innermolecular reactions. Hence, diazirine 8 was photolyzed in various conventional solvents to gauge the intermolecular reactivity of carbene 9. Relevant results were used to rationalize the CyD innermolecular reaction products. 相似文献
498.
A. S. Rosenberg E. I. Aleksandrova N. P. Ivleva G. I. Dzhardimalieva A. V. Raevskii O. I. Kolesova I. E. Uflyand A. D. Pomogailo 《Russian Chemical Bulletin》1998,47(2):259-264
Thermal conversion of cobalt(II) maleate, CoC4H2O42H2O, (1) at 340–370 °C was studied. The composition of the products of pyrolysis was determined. The major solid-phase product of decomposition consists of nano-sized particles of CoO (sizes vary within narrow limits) stabilized by the polymeric matrix. Thermal conversions of CoII maleate involve dehydration, polymerization of dehydrated monomers, and decarboxylation of the resulting polymer. 相似文献
499.
Michael Day Shariff E. Kabir Erich Wolf Edward Rosenberg Kenneth I. Hardcastle 《Journal of Cluster Science》1990,1(4):355-369
The synthesis of (-H)(-2-RRNCO2)Os3(CO)10 (R=R=CH3
2a; R=R=CH2CH3,2b; R=CH3, R=CH2CH3,2c) and their cyclic analogs (-H)(-2--CO2)Os3(CO)10(n=42d,n=5,2e) from carbon dioxide, secondary amine, and Os3(CO)10(CH3CN)2 (1) are reported. A solid-state structure of2c reveals a bonding mode for the carbamato ligand very similar to that observed for related carboxylato complexes. Compound2c crystallizes in the orthorombic space group Pbca witha=9.136 (3),b=15.310 (4) andc=30.361 (5) Å;V=4247 Å3,Z=8. Least-squares refinement of 2405 observed reflections gave a final agreement factor ofR=0.043 (R
w
=0.043). The reactivity of the complexes2a–2e was examined. Compound2c or2b give good yields of the cluster derivatives (-H)(-X)Os3(CO)10 (X=Cl,3; X=OCH3,4; X=N(CH3)2,7) when reacted with HX. Reaction of2a with P(CH3)3 at 68°C gives good yields of the otherwise difficult to obtain 1,1,2-(P(CH3)3)3Os3(CO)9 (5). Evidence is presented that suggests that2a–2e form by oxidative addition of preformed carbamic acids to1. 相似文献
500.
A computer program for calculating activation analysis results is described. The program comprises two gamma spectrum analysis
programs, STOAV and SAMPO and one program for calculating elemental concentrations, KVANT. STOAV is based on a simple summation
of channels and SAMPO is based on fitting of mathematical functions. The programs are tested by analyzing the IAEA G-1 test
spectra. In the determination of peak location SAMPO is somewhat better than STOAV and in the determination of peak area SAMPO
is more than twice as accurate as STOAV. On the other hand, SAMPO is three times as expensive to use with a Cyber 170 computer
as STOAV. 相似文献