全文获取类型
收费全文 | 1010篇 |
免费 | 43篇 |
国内免费 | 8篇 |
专业分类
化学 | 514篇 |
晶体学 | 20篇 |
力学 | 26篇 |
数学 | 345篇 |
物理学 | 156篇 |
出版年
2023年 | 14篇 |
2022年 | 44篇 |
2021年 | 53篇 |
2020年 | 49篇 |
2019年 | 54篇 |
2018年 | 45篇 |
2017年 | 45篇 |
2016年 | 56篇 |
2015年 | 34篇 |
2014年 | 48篇 |
2013年 | 78篇 |
2012年 | 49篇 |
2011年 | 56篇 |
2010年 | 45篇 |
2009年 | 32篇 |
2008年 | 49篇 |
2007年 | 44篇 |
2006年 | 30篇 |
2005年 | 19篇 |
2004年 | 22篇 |
2003年 | 22篇 |
2002年 | 24篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 7篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1957年 | 2篇 |
1939年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有1061条查询结果,搜索用时 15 毫秒
941.
In interferogram or fringe pattern analysis, a technique capable of automatically analyzing interferograms that contain complex fringes and high-level noise as well as defects is highly demanded. In this paper, a hybrid technique combining the concepts of the two-dimensional continuous wavelet transform technique and the phase-shifting technique is proposed. The novel technique takes the advantages of the two existing techniques, and has the ability to accurately and automatically analyze multiple phase-shifted complex interferograms involving noise and defects. The validity of the technique is demonstrated by both computer simulation and real experiment. 相似文献
942.
Salvatore Iavarone Arthur Péquin Zhi X. Chen Nguyen Anh Khoa Doan Nedunchezhian Swaminathan Alessandro Parente 《Proceedings of the Combustion Institute》2021,38(4):5403-5414
Moderate or Intense Low-oxygen Dilution (MILD) combustion has drawn increasing attention as it allows to avoid the thermo-chemical conditions prone to the formation of pollutant species while ensuring high energy efficiency and fuel flexibility. MILD combustion is characterized by a strong competition between turbulent mixing and chemical kinetics so that turbulence-chemistry interactions are naturally strengthened and unsteady phenomena such as local extinction and re-ignition may occur. The underlying physical mechanisms are not fully understood yet and the validation of combustion models featuring enhanced predictive capabilities is required. Within this context, high-fidelity data from Direct Numerical Simulation (DNS) represent a great opportunity for the assessment and the validation of combustion closure formulations. In this study, the performance of the Partially Stirred Reactor (PaSR) combustion model in MILD conditions is a priori assessed on Direct Numerical Simulations (DNS) of turbulent combustion of MILD mixtures in a cubical domain. Modeled quantities of interest, such as heat release rate and reaction rates of major and minor species, are compared to the corresponding filtered quantities extracted from the DNS. Different submodels for the key model parameters, i.e., the chemical time scale τc and the mixing time scale τmix, are considered and their influence on the results is evaluated. The results show that the mixing time scale is the leading scale in the investigated cases. The best agreement with the DNS data regarding the prediction of heat release rate and chemical source terms is achieved by the PaSR model that employs a local dynamic approach for the estimation of the mixing time scale. An overestimation of the OH species source terms occurs in limited zones of the computational domain, characterized by low heat release rates. 相似文献
943.
Predicting the subcellular location of apoptosis proteins based on recurrence quantification analysis and the Hilbertben Huang transform 下载免费PDF全文
Apoptosis proteins play an important role in the development and homeostasis of an organism. The elucidation of the subcellular locations and functions of these proteins is helpful for understanding the mechanism of programmed cell death. In this paper, the recurrent quantification analysis, Hilbert-Huang transform methods, the maximum relevance and minimum redundancy method and support vector machine are used to predict the subcellular location of apoptosis proteins. The validation of the jackknife test suggests that the proposed method can improve the prediction accuracy of the subcellular location of apoptosis proteins and its application may be promising in other fields. 相似文献
944.
Vo Van Tan 《Commentarii Mathematici Helvetici》1982,57(1):196-201
Unless the contrary is explicitly stated, allℂ-analytic spaces considered here are assumed to be non compact, countable at
infinity and of bounded Zariski dimension.
The author gratefully acknowledges the generous support from the N.S.F. Grant #MCS 81-02266. Also he would like to thank Prof.
H. Hironaka for bringing this problem to his attention. 相似文献
945.
Conclusions 1. Peregrinol and two new diterpenoids—marrubiol and vulgarol—have been isolated from the plantMarrubium vulgare L. for the first time.2. The structure of marrubiol (I), which is possibly a biogenetic precursor of marrubiin, has been demonstrated.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 6, pp. 345–348, 1968 相似文献
946.
947.
B. Kh. Baîramov V. A. Voįtenko B. P. Zakharchenya V. V. Toporov M. Henini A. J. Kent 《JETP Letters》1998,67(11):972-977
The development of a method for registering quasielastic electronic light scattering spectra in the near-IR region, which makes it possible to detect light scattering by a photoexcited electron-hole plasma induced in a GaAs layer in the presence of a self-organized ensemble of InAs quantum dots, is reported. A substantial resonance intensification of such scattering, two orders of magnitude greater than the values established for the bulk material, is observed, and the main mechanism of such scattering is determined. 相似文献
948.
949.
Vo Van Tan 《manuscripta mathematica》1990,69(1):333-338
In contrast with the 2-dimensional case, we would like to exhibit here an example of a compactifiable strongly pseudoconvex
threefold X such that a) the analytic Kodaira dimension κ(X)=3 and b) its exceptional subvariety S is projective algebraic;
yet X is not quasi-projective. 相似文献
950.