全文获取类型
收费全文 | 152篇 |
免费 | 6篇 |
国内免费 | 11篇 |
专业分类
化学 | 66篇 |
晶体学 | 1篇 |
力学 | 4篇 |
综合类 | 1篇 |
数学 | 20篇 |
物理学 | 77篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 12篇 |
2011年 | 15篇 |
2010年 | 8篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 12篇 |
2005年 | 12篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1991年 | 1篇 |
排序方式: 共有169条查询结果,搜索用时 62 毫秒
131.
为了给侵彻引信抗高过载优化设计提供准确的力学输入,将机械振动理论引入侵彻过程建模领域,提出了一种侵彻战斗部刚体运动与一阶轴向振动相结合的垂直侵彻弹靶作用模型。在垂直侵彻过程受力分析的基础上,基于牛顿第二定律建立了战斗部刚体运动模型,基于单自由度弹簧-质量-阻尼系统建立了战斗部一阶轴向振动模型,并采用数值积分的方法获得了垂直侵彻过程中各物理量的变化规律。和火炮试验实测加速度信号的对比分析结果表明:考虑战斗部一阶轴向振动后的垂直侵彻弹靶作用模型能更准确地描述侵彻过程,能更有效地指导侵彻引信的抗高过载优化设计。 相似文献
132.
133.
134.
135.
Lin Yang Shuaidong Zhu Zhimei He Xiangli Li Jiangning Chen Sai Bi Jun-Jie Zhu 《中国化学快报》2022,33(1):314-319
Herein, the nanoscaled ATP-responsive upconversion metal-organic frameworks(UCMOFs) are aqueousphase synthesized for co-delivery of therapeutic protein cytochrome c(Cyt c) and chemodrugs doxorubicin(DOX), achieving targeted combinational therapy of human cervical cancer. The UCMOFs are rationally fabricated by growing ZIF-90 on mesoporous silica-coated upconversion nanoparticles(UCNPs),in which the ZIF-90 layer attenuates the upconversion luminescence(UCL) and the rigid frameworks increase the s... 相似文献
136.
137.
In oxidative electrochemical organic synthesis, radical intermediates are often oxidized to cations on the way to final product formation. Herein, we describe an approach to transform electrochemically generated organic radical intermediates into neutral products by reaction with a metal catalyst. This approach combines electrochemical oxidation with Cu catalysis to effect formal aza‐Wacker cyclization of internal alkenes. The Cu catalyst is essential for transforming secondary and primary alkyl radical intermediates into alkenes. A wide range of 5‐membered N‐heterocycles including oxazolidinone, imidazolidinone, thiazolidinone, pyrrolidinone, and isoindolinone can be prepared under mild conditions. 相似文献
138.
Sun X He J Cai G Lin A Zheng W Liu X Chen L He X Zhang Y 《Journal of separation science》2010,33(23-24):3786-3793
A novel molecularly imprinted polymer monolith was prepared by the room temperature ionic liquid-mediated in situ molecular imprinting technique, using norfloxacin (NOR) as the template, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker. The optimal synthesis conditions and recognition properties of NOR-imprinted monolithic column were investigated. The results indicated that the imprinted monoliths exhibited good ability of selective recognition against the template and its structural analog. Using the fabricated material as solid-phase extraction sorbent, a sample pre-treatment procedure of molecularly imprinted solid-phase extraction coupling with HPLC was developed for determination of trace quinolone residues in animal tissues samples. The recoveries ranging from 78.16 to 93.50% for eight quinolones antibiotics such as marbofloxacin, NOR, ciprofloxacin, danofloxacin, difloxacin, oxolinic acid, flumequine and enrofloxacin were obtained. 相似文献
139.
Weixuan Sun Wenhan Yang Yuxue Zheng Huiling Zhang Haitian Fang Donghong Liu Xiangli Kong Shiguo Chen Xingqian Ye Jinhu Tian 《Molecules (Basel, Switzerland)》2020,25(23)
In order to broaden the application of potato pulp pectic polysaccharide (PPP) in stabilizing acidified milk drinks (AMDs) and investigate the stabilizing effect and physical properties of AMDs prepared with PPP, a comparative study was made among PPP, commercial high methoxyl pectin (HMP) and low methoxyl pectin (LMP). The zeta potential, rheology, particle size and serum separation of AMDs were evaluated after preparing with PPP, HMP and LMP, respectively. Results indicated that PPP led to lower serum separation than LMP (14.65% for AMDs prepared with 0.5% PPP compared to 25.05% for AMDs prepared with 0.5% LMP), but still higher than HMP (9.09% for AMDs prepared with 0.5% HMP). However, narrower particle size distribution and lower viscosity of AMDs was achieved by PPP than by LMP and HMP. PPP can electrostatically adsorb on the surface of casein and its abundant neutral sugar side chains would provide steric hindrance to prevent casein flocculation in AMDs. Our results might provide some new ideas for the application of PPP in improving the stability of AMDs. 相似文献
140.
Ning Xiangli Liang Hongbo Bu Jiang Xiong Lei Huang Shengmei Xu Haitao 《Journal of Thermal Analysis and Calorimetry》2018,132(3):1795-1804
Journal of Thermal Analysis and Calorimetry - A novel tri-substituted triazine in which substituted methacrylated piperzinyl (TMAPT) was synthesized and was then blended with di(acryloyloxy propyl)... 相似文献