全文获取类型
收费全文 | 1010篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
化学 | 516篇 |
晶体学 | 70篇 |
力学 | 20篇 |
数学 | 113篇 |
物理学 | 299篇 |
出版年
2020年 | 4篇 |
2019年 | 11篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2014年 | 7篇 |
2013年 | 31篇 |
2012年 | 29篇 |
2011年 | 76篇 |
2010年 | 38篇 |
2009年 | 26篇 |
2008年 | 45篇 |
2007年 | 33篇 |
2006年 | 29篇 |
2005年 | 31篇 |
2004年 | 30篇 |
2003年 | 24篇 |
2002年 | 29篇 |
2001年 | 34篇 |
2000年 | 23篇 |
1999年 | 18篇 |
1998年 | 21篇 |
1997年 | 14篇 |
1996年 | 20篇 |
1995年 | 27篇 |
1994年 | 17篇 |
1993年 | 17篇 |
1992年 | 25篇 |
1991年 | 17篇 |
1990年 | 19篇 |
1989年 | 20篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 19篇 |
1984年 | 23篇 |
1983年 | 11篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 20篇 |
1979年 | 18篇 |
1978年 | 12篇 |
1977年 | 23篇 |
1976年 | 13篇 |
1975年 | 11篇 |
1974年 | 5篇 |
1973年 | 11篇 |
1972年 | 8篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1930年 | 4篇 |
排序方式: 共有1018条查询结果,搜索用时 921 毫秒
61.
62.
63.
64.
65.
Aldol/elimination reactions of ß-ketoamides with methyl glyoxylate result in highly selective production of Z-α,ß-unsaturated amides. An intramolecular Diels-Alder reaction of a triply activated dienophile derived from chiral dienylamine 7ZE stereospecifically affords chiral bicyclic lactam 11 at room temperature. 相似文献
66.
Peptide prefractionation is essential for proteomic approaches employing multiple‐reaction monitoring of fruit proteomic research
下载免费PDF全文
![点击此处可从《Journal of separation science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jun Song Leslie Campbell Palmer XiHong Li ZhaoQi Zhang 《Journal of separation science》2014,37(1-2):77-84
Off‐gel? IEF has become a popular tool in proteomics research to fractionate peptides or proteins. We conducted a detailed investigation on the fruit proteomics of apple, banana, and strawberry fruit employing Off‐gel? electrophoresis (OGE) as a crucial step to improve the proteome coverage and quantitative proteomic workflows including multiple‐reaction monitoring (MRM). We provide technical details concerning the application of Off‐gel?IEF, nano‐LC–MS detection, and MRM optimization and analysis. Our results demonstrated that the application of OGE is an effective method for peptide fractionation and increased significantly the number of proteins identified by at least ten times, with more total peptides detected and collected. Furthermore, we developed a protocol combining OGE and MRM studies to identify and quantitatively investigate monodehydroascorbate reductase, a key enzyme in the redox and antioxidant system of apple fruit during fruit ripening. Using this method, the quantitative changes in this protein during ripening and in response to ethylene treatment was investigated. Our results provide direct and comprehensive evidence demonstrating the benefits of OGE and its application for both shotgun and quantitative proteomics research. 相似文献
67.
68.
Mathew A. Cleveland Nick A. Gentile Todd S. Palmer 《Journal of computational physics》2010,229(16):5707-5723
Implicit Monte Carlo (IMC) and Implicit Monte Carlo Diffusion (IMD) are approaches to the numerical solution of the equations of radiative transfer. IMD was previously derived and numerically tested on grey, or frequency-integrated problems [1]. In this research, we extend Implicit Monte Carlo Diffusion (IMD) to account for frequency dependence, and we implement the difference formulation [2] as a source manipulation variance reduction technique. We derive the relevant probability distributions and present the frequency dependent IMD algorithm, with and without the difference formulation. The IMD code with and without the difference formulation was tested using both grey and frequency dependent benchmark problems. The Su and Olson semi-analytic Marshak wave benchmark was used to demonstrate the validity of the code for grey problems [3]. The Su and Olson semi-analytic picket fence benchmark was used for the frequency dependent problems [4]. The frequency dependent IMD algorithm reproduces the results of both Su and Olson benchmark problems. Frequency group refinement studies indicate that the computational cost of refining the group structure is likely less than that of group refinement in deterministic solutions of the radiation diffusion methods. Our results show that applying the difference formulation to the IMD algorithm can result in an overall increase in the figure of merit for frequency dependent problems. However, the creation of negatively weighted particles from the difference formulation can cause significant numerical instabilities in regions of the problem with sharp spatial gradients in the solution. An adaptive implementation of the difference formulation may be necessary to focus its use in regions that are at or near thermal equilibrium. 相似文献
69.
Application-specific optimization of disordered nanoporous carbons remains a formidable challenge due to the difficulty in
accurately characterizing their microstructures with current empirical methods. Using molecular simulation techniques, we
investigated the adsorptive and diffusive behavior of argon in three models of disordered nanoporous carbons. We found that
the structural and morphological differences between these models gave rise to distinct phenomenological properties. The adsorptive
behavior of argon in both the low and high pressure regimes was enhanced dramatically in the models with more crystalline
microstructures. As for dynamic properties, we found that the adsorbent’s structure and energetic topology significantly alters
the rates of diffusion as well as the characteristics of the underlying diffusion mechanisms. 相似文献
70.
R. Alan Aitken Bernd Fodi Michael H. Palmer Alexandra M.Z. Slawin Jing Yang 《Tetrahedron》2012,68(29):5845-5851
The structures of pyridazine N-oxide, pyrimidine N-oxide and pyrazine N-oxide have been determined by X-ray diffraction for the first time. Comparison with theoretical predictions of the equilibrium structures using the B3LYP method together with a cc-pVTZ basis set, show close agreement with the structural parameters observed, and experimental dipole moments, which suggests that the charge distribution is realistic. An ‘atoms in molecules’ (AIM) analysis of the computed wave-functions shows total electron densities rather different from the classical picture of a dative bond, whereas the same wave-functions subjected to Mulliken analysis show a more conventional view of the electron distribution. This latter procedure allows a bond dipole analysis of the N-oxide charge distribution. 相似文献