全文获取类型
收费全文 | 375篇 |
免费 | 8篇 |
专业分类
化学 | 182篇 |
晶体学 | 7篇 |
力学 | 23篇 |
数学 | 36篇 |
物理学 | 135篇 |
出版年
2022年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2013年 | 14篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 19篇 |
2005年 | 8篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1973年 | 12篇 |
1972年 | 3篇 |
1970年 | 4篇 |
1941年 | 4篇 |
1939年 | 4篇 |
1938年 | 2篇 |
1913年 | 2篇 |
1899年 | 3篇 |
排序方式: 共有383条查询结果,搜索用时 15 毫秒
71.
72.
John J. Goodell Christine M. Egnatuk Stephen W. Padgett Corey C. Keith Todd A. Bredeweg Norris K. Harward Bryan B. Bandong Kevin E. Roberts Alice C. Mignerey 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(2):475-483
Theoretical activation calculations for Fe, Ni, and stainless steel foils were compared against irradiated foil measurements from a critical assembly. Calculated/experiment values spanning 0.62–1.31 showed that the restricted approach used here is insufficient for experiment planning, with the collapsed cross-section being the primary source of error. The effect of decay time on gamma-ray spectroscopy measurement reliability was investigated using a Monte Carlo HPGe detector model. Simulations showed no correlation with decay time, absent interferences. Specific interferences for Fe-59 (Ni) and Co-60 (stainless steel) activation product ratios suggested optimal measurement windows having respective decay times of 9–11 days and 4–7 days. 相似文献
73.
Small amounts of self-phase modulation can lead to significant pulse distortions in chirped-pulse amplifiers. However, we show the surprising result that the strong chirp of the pulse can be exploited to remove these distortions completely by linear pulse shaping before amplification. 相似文献
74.
Wu G Norris C Stewart H Cox H Stace AJ 《Chemical communications (Cambridge, England)》2008,(35):4153-4155
A combined theoretical and experimental study of electronic transitions in the complex [Zn(pyridine)(4)](2+) provides the first example of a state-resolved electronic spectrum to be recorded for a dication complex in the gas phase. 相似文献
75.
Legent G Delaune A Norris V Delcorte A Gibouin D Lefebvre F Misevic G Thellier M Ripoll C 《The journal of physical chemistry. B》2008,112(17):5534-5546
Localizing two or more components of assemblies in biological systems requires both continued development of fluorescence techniques and invention of entirely new techniques. Candidates for the latter include dynamic secondary ion mass spectrometry (D-SIMS). The latest generation of D-SIMS, the Cameca NanoSIMS 50, permits the localization of specific, isotopically labeled molecules and macromolecules in sections of biological material with a resolution in the tens of nanometers and with a sensitivity approaching in principle that of a single protein. Here we use two different systems, crystals of glycine and mixtures of proteins, to show that the formation of recombinant CN secondary ions under Cs bombardment can be exploited to create a new colocalization technique. We show experimentally that the formation of the recombinant (13)C(15)N secondary ion between (13)C- and (15)N-labeled macromolecules is indeed an indicator of the distance between the interacting macromolecules and on their shape. We build up a convolution model of the mixing-recombination process in D-SIMS that allows quantitative interpretations of the distance-dependent formation of the recombinant CN. Our results show that macromolecules can be colocalized if they are within 2 nm of one another. We discuss the potential advantages of this new technique for biological applications. 相似文献
76.
Zerrouk Z Alexandre S Lafontaine C Norris V Valleton JM 《Colloids and surfaces. B, Biointerfaces》2008,63(2):306-310
In prokaryotic cells, the hypothesis of the existence of lipid domains was considered. In order to test this hypothesis and study the organization of lipids in the inner membrane of Escherichia coli, we elaborated Langmuir films mimicking the inner leaflet of this membrane by considering lipids extracted from the inner membrane of E coli by Folch protocol.
Lipid monolayers were elaborated by using these extracts (Langmuir technique); the organization of the resulting films was studied at the air–water interface by Brewster angle microscopy and after transfer onto muscovite by atomic force microscopy. The existence of domains was demonstrated for different interfacial pressures of biological interest, and their stability was studied. 相似文献
77.
Constanti Magda Giralt Jaume Bordons Albert Norris Paul R. 《Applied biochemistry and biotechnology》1992,(1):767-776
The growth and oxygen consumption of a variety of thermophilic, acidophilic bacteria in the presence of thiophene-2-carboxylate
(T2C) and dibenzothiophene (DBT) have been determined. T2C was extremely toxic to the acidophiles in comparison with neutrophiles,
but appeared to be degraded by a heterotrophicSulfolobus- like thermophile. DBT proved to be unstable at high temperatures, even in the absence of bacteria, and was not a substrate for
the thermophiles. 相似文献
78.
Stephanie M. Delgado Sam C. P. Norris Andrea M. Kasko 《Journal of polymer science. Part A, Polymer chemistry》2022,60(5):825-841
Hydrogels are attractive materials for generating 4D shapes due to their ability to undergo pronounced volume changes in response to several stimuli, including light. We previously reported shape-changing hydrogels actuated by long-wave UV and visible light in the presence of live cells using poly(ethylene glycol) macromers incorporating different photodegradable ortho-nitrobenzyl (o-NB) groups. In this comprehensive study, we determine the effect of chemical structure of different o-NB macromers (which influences molar absorptivity and rate constant of degradation), composition (macromer weight percent), fabrication design (initial gel thickness) and environment (ionic strength of solution) on light-induced hydrogel folding. We demonstrate successful photopolymerization and subsequent photodegradation of hydrogels, multistep folding, and live-cell encapsulation. This hydrogel system may be useful as new tool in stem cell differentiation and developmental biology research, facilitating the in vitro investigation of processes that are sensitive to both physical and temporal stimuli. 相似文献
79.
Bearden IG Beavis D Besliu C Blyakhman Y Budick B Bøggild H Chasman C Christensen CH Christiansen P Cibor J Debbe R Enger E Gaardhøje JJ Hagel K Hansen O Holm A Holme AK Ito H Jakobsen E Jipa A Jørdre JI Jundt F Jørgensen CE Karabowicz R Keutgen T Kim EJ Kozik T Larsen TM Lee JH Lee YK Løvhøiden G Majka Z Makeev A McBreen B Mikelsen M Murray M Natowitz J Nielsen BS Norris J Olchanski K Olness J Ouerdane D Płaneta R Rami F Ristea C Röhrich D Samset BH Sandberg D Sanders SJ Sheetz RA Staszel P 《Physical review letters》2002,88(20):202301
We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at square root[s(NN)] = 200 GeV. For the 5% most central events we obtain dN(ch)/deta/(eta = 0) = 625+/-55 and N(ch)/(-4.7< or =eta < or =4.7) = 4630 +/- 370, i.e., 14% and 21% increases, respectively, relative to square root[s(NN)] = 130 GeV collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy. 相似文献
80.
Nonreciprocal and directional wave propagation in a two-dimensional lattice with bilinear properties
Nonlinear Dynamics - A passive method of realizing nonreciprocal wave propagation in a two-dimensional (2D) lattice is proposed, using bilinear springs combined with the necessary spatial asymmetry... 相似文献