全文获取类型
收费全文 | 145篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
化学 | 90篇 |
晶体学 | 2篇 |
力学 | 13篇 |
数学 | 31篇 |
物理学 | 20篇 |
出版年
2024年 | 1篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 14篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 11篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2003年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
排序方式: 共有156条查询结果,搜索用时 0 毫秒
151.
Gholamreza Nikbakht Brujeni Darioush Gharibi 《Applied biochemistry and biotechnology》2012,167(1):14-23
Mycobacterium avium subsp. paratuberculosis heat shock protein 70 (MAPHsp70) is an immunodominant antigen, which can be used as a subunit vaccine against bovine paratuberculosis. In the present study, we evaluated the immunogenic activities of MAPHsp70 expressed by DNA vaccine in chicken and the use of prepared specific avian IgY antibodies for western blotting and ELISA methods. The gene encoding MAP Hsp70 was subcloned into the eukaryotic expression vector, pcDNA3.1, and the recombinant plasmid (pcDNA3.1-MAP Hsp70) transfected into COS-7 cells. Chickens were also immunized with pcDNA3.1-MAP Hsp70, and egg yolk antibodies extracted from eggs were collected after immunization. DNA-designed IgY antibody was used in Western blotting analysis to detect the expression of MAPHsp70, and in a sandwich ELISA to assess the prevalence of anti-MAPHsp70 antibodies in cattle serum. Western blotting results indicate the expression of rMAP hsp70 in COS-7 cells and sandwich ELISA could detect anti-MAPHsp70 antibodies in 7.5% of cows. Chicken immunization with pcDNA3.1-MAPHsp70 could demonstrate the effective production of anti-MAPHsp70 IgY antibodies. Monospecific anti-MAPHsp70 antibody generated in chickens is useful for detection of MAPHsp70 peptide in cell culture and MAP lysate. 相似文献
152.
Hassan Salarieh Seyyed Mostafa Mostafavi Kashani Gholamreza Vossoughi Aria Alasty 《Communications in Nonlinear Science & Numerical Simulation》2009,14(3):839-849
The problem of stabilizing unstable fixed points of nonlinear discrete chaotic systems, subjected to bounded model uncertainties, is investigated in this article. The theory is then generalized to include any dth-order fixed point of the system. To design a suitable controller, the theory of quasi-sliding mode control is modified and applied. Sufficient conditions for the convergence of the control algorithm are theoretically derived and it is shown that the error trajectories converge toward a bounded region around zero where the measure of the steady-state error band depends on the magnitude of the system uncertainties. As a case study, the proposed method is applied to the Henon map to stabilize its first, second, and fourth-order unstable fixed points. Simulation results show the high performance of the control technique in quenching the chaos in the presence of uncertainties. 相似文献
153.
In this paper, we propose a new class of multistep collocation methods for solving nonlinear Volterra Integral Equations,
based on Hermite interpolation. These methods furnish an approximation of the solution in each subinterval by using approximated
values of the solution, as well as its first derivative, in the r previous steps and m collocation points. Convergence order of the new methods is determined and their linear stability is analyzed. Some numerical
examples show efficiency of the methods. 相似文献
154.
Hamed Moradi Firooz Bakhtiari-Nejad Mohammad R. Movahhedy Gholamreza Vossoughi 《Journal of sound and vibration》2012,331(21):4668-4690
In this paper, a tunable vibration absorber set (TVAs) is designed to suppress regenerative chatter in milling process (as a semi-active controller). An extended dynamic model of the peripheral milling with closed form expressions for the nonlinear cutting forces is presented. The extension part of the cutting tool is modeled as an Euler–Bernoulli beam with in plane lateral vibrations (x–y directions). Tunable vibration absorbers in x–y directions are composed of mass, spring and dashpot elements. In the presence of regenerative chatter, coupled dynamics of the system (including the beam and x–y absorbers) is described through nonlinear delay differential equations. Using an optimal algorithm, optimum values of the absorbers' position and their springs' stiffness in both x–y directions are determined such that the cutting tool vibration is minimized. Results are compared for both linear and nonlinear models. According to the results obtained, absorber set acts effectively in chatter suppression over a wide range of chatter frequencies. Stability limits are obtained and compared with two different approaches: a trial and error based algorithm and semi-discretization method. It is shown that in the case of self-excited vibrations, the optimum absorber improves the process stability. Therefore, larger values of depth of cut and consequently more material removal rate (MRR) can be achieved without moving to unstable conditions. 相似文献
155.
Hamed Moradi Mohammad R. Movahhedy Gholamreza Vossoughi 《Journal of sound and vibration》2012,331(16):3844-3865
In this paper, internal resonance and nonlinear dynamics of regenerative chatter in milling process is investigated. An extended dynamic model of the peripheral milling process including both structural and cutting force nonlinearities is presented. Closed form expressions for the nonlinear cutting forces are derived through their Fourier series components. In the presence of the large vibration amplitudes, the loss of contact effect is included in this model. Using the multiple-scales approach, analytical approximate response of the delayed nonlinear system is obtained. Considering the internal resonance dynamics (i.e. mode coupling), the energy transfer between the coupled x–y modes is studied. The results show that during regenerative chatter under specific cutting conditions, one mode can decay. Furthermore, it is possible to adjust the rate at which the x-mode (or y-mode) decays by implementation of the internal resonance. Therefore, under both internal resonance and regenerative chatter conditions, it is possible to suppress the undesirable vibration of one mode (direction) in which accurate surface finish is required. Under the steady-state motion, jump phenomenon is investigated for the process with regenerative chatter under various cutting conditions. Moreover, the effects of structural and cutting force nonlinearities on the stability lobes diagram of the process are investigated. 相似文献
156.