全文获取类型
收费全文 | 86篇 |
免费 | 0篇 |
国内免费 | 10篇 |
专业分类
化学 | 45篇 |
力学 | 9篇 |
综合类 | 1篇 |
数学 | 14篇 |
物理学 | 5篇 |
无线电 | 22篇 |
出版年
2023年 | 11篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2009年 | 9篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有96条查询结果,搜索用时 46 毫秒
51.
Ming Kai Wei Zhang Huan Xie Liwei Liu Sujie Huang Xiao Li Zhengzheng Zhang Yuyang Liu Bangzhi Zhang Jingjing Song Rui Wang 《中国化学快报》2018,29(7):1163-1166
Conformational flexibility induced by proline and aminocaproic acid can increase anticancer activity and antimicrobial activity of dimeric antimicrobial peptides with reduced hemolytic activity. This study will contribute to the design of efficient antimicrobial peptides. 相似文献
52.
Philipp Wacker Erich Kleinpeter 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):331-339
Both the stoichiometry and complex stability constants of crown ether complexes with metal ions have been determined by examining
gradual changes in their diffusional behavior in nonaqueous solution. Diffusion coefficients, D, were evaluated by pulsed field gradient (PFG) NMR titration experiments whilst complex stability constants were determined
by nonlinear curve-fitting procedures, D versus csol., which also allow the treatment of multiple complexation equilibria (1:1 to 1:2 stoichiometries). Differences in the diffusion
coefficients of the various free crown ethers with respect to their metal ion complexes indicate great sensitivity to both
conformational changes and changes in molecular size upon complexation. 相似文献
53.
提出基于IMS网络的CTD业务平台设计,介绍了CTD平台内部各功能模块及与短信中心、彩信中心、计费、网管等外界系统对接的架构,分析了各分体系的特性。点击拨号所使用的不同场景,提出各种场景所对应的话务模型,通过各种业务需求分析确定平台建设规模,提出计算方法并计算出硬件设备配置,同时提出软件架构。根据网络路由组织原则及网络安全技术要求提出实现该业务功能的网络连接方案。最后根据现网电信运营商应用情况,对CTD平台进行分析总结。 相似文献
54.
本文简要介绍了移动通信的发展趋势,通过Ad Hoc网络与传统网络的比较,阐述了两者的主要区别。说明了灵活性是第四代移动通信中Ad Hoc网络最大的优点。通过举例,实例化Ad Hoc网络技术特点。 相似文献
55.
《Operations Research Letters》2020,48(3):249-256
We focus on the problem of choosing the optimal recycled content claim under stochastic local recycled content availability under two claim types — period specific (when claims have to hold each period) and average (when claims are evaluated across periods). We show conditions under which specific claims are higher than average claims, and explore cases where the optimal claims and profits are aligned to be in the same direction. 相似文献
56.
A. R. Naghavi Riabi 《基于设计的结构力学与机械力学》2015,43(4):407-423
In this article, a numerical method is presented for computing the stiffness matrix and compatibility relations of cables under uniform distributed loads on any direction. Both the geometrical and material nonlinearities, including softening and yielding of material, are taken into account and the catenary cable element with gauss integration scheme is employed. The proposed formulation includes the effect of uniform distributed loads on any direction and 3D nodal forces to assess the geometric and possible material nonlinearity of cables. The derived equations are then applied to the analysis of cable structures. The accuracy of the responses obtained by the proposed method is evaluated by several benchmark solutions available in the literature. Results of numerical examples indicate the capability of the proposed stiffness matrix in prediction of the elastic and inelastic responses of cables. The proposed formulation is therefore recommended for cable elements to be used in the analysis of cable structures. 相似文献
57.
以制备的阳极氧化不锈钢模板为模具嵌件, 采用注射压缩成型(ICM)工艺快速成型表面具有纳米丝结构的柔性聚丙烯/乙烯-辛烯共聚物(PP/POE, PP与POE质量比为3∶1)共混物复制物和准刚性PP复制物, 研究常温液滴冲击?10 ℃复制物表面的动态行为. 结果表明, 致密的纳米丝使复制物表面呈现超疏水、 极低黏附的润湿状态. 在低冲击速度范围内, 共混物复制物表面上液滴的接触时间比PP复制物上的短, 可归因于液滴铺展阶段柔性纳米丝储存的弹性势能在回缩阶段转换为液滴的动能; 在高冲击速度范围内, 共混物复制物基板和纳米丝储存的弹性势能被转换为液滴的动能, 进一步缩短了液滴的接触时间. 此结果表明, 共混物复制物的柔性和表面超疏水性使其具有优异的防冻黏性能. 共混物复制物表面上水滴(50 μL)的结冰时间得到明显延长、 冰黏附强度明显降低. 研究结果表明, 可采用ICM快速成型具有优异防冻黏和防冰性能的柔性超疏水高分子材料表面. 相似文献
58.
The complex model of Thermus thermophilus xylose isomerase (TtXI) with D-xylose was constructed, and molecular dynamics (MD) simulations were carried out at 300 and 360 K for 10 ns by NAMD2.5. The radius of gyration (Rg), subunit interactions, and residue flexibility were analyzed. The results show that residues 60-69, 142-148, 169-172, and 332-340 have high flexibility at 300 and 360 K. Residues with higher flexibility at 360 K than that at 300 K can mainly be divided into two groups: one locates in the helix-loophelix region consisting of residues 55-80 in catalytic domain; the other at subunit interfaces. The Rg of catalytic domain at 360 K shows 0.16 A higher than that at 300 K, but Rg of small C-terminal domain has no obvious difference. The results indicate that enhanced Rg of catalytic domain may lead to the intense motion of the active site of TtXI and promote the D-xylose isomization reaction. Eight hydrogen bonds and five ion pairs are reduced at subunit interfaces at 360 K compared with 300 K, that may be the main reason for the decrease in rigidity and increase in activity at high temperature of TtXI. This result also help to explain the cold-adaption phenomenon of TtXI E372G mutant reported previously. Our results reveal the relationship between temperature and structure flexibility of TtXI, and play an important role in understanding the thermostability of thermophile protein with multiple subunits. 相似文献
59.
Powell dynamic identification of displacement parameters of indeterminate thin-walled curve box based on FCSE theory 总被引:1,自引:0,他引:1
Jian Zhang · Chu-Wei Zhou · Jia-Shou Zhuo College of Aerospace Engineering Nanjing University of Aeronautics Astronautics Nanjing China College of Mechanics Material Hohai University Nanjing China 《Acta Mechanica Sinica》2011,27(3):452-460
The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory,dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples,it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence,which demonstrates that the presented method and the compiled procedure are correct and reliable.During parameters’ iterative processes,the Powell theory is irrelevant with the calculation of finite curve strip element(FCSE) partial differentiation,which proves high computation effciency of the studied method. 相似文献
60.
《Journal of Coordination Chemistry》2012,65(16):2821-2828
A new compound, [{CuI(bim)}4{SiW12O40}] (1) (bim?=?1,2-bis(imidazol-1′-yl)ethane), was hydrothermally synthesized and characterized by elemental analyses, IR, TG, and single-crystal X-ray diffraction. Compound 1 is an infinite 1-D chain composed of Cu-bim coordination polymers and [α-SiW12O40]4? polyanions. The electrochemical and electrocatalytic behaviors of 1-modified carbon paste electrode (1-CPE) have been studied. 相似文献