全文获取类型
收费全文 | 1545篇 |
免费 | 278篇 |
国内免费 | 163篇 |
专业分类
化学 | 1081篇 |
晶体学 | 10篇 |
力学 | 144篇 |
综合类 | 35篇 |
数学 | 182篇 |
物理学 | 534篇 |
出版年
2024年 | 5篇 |
2023年 | 43篇 |
2022年 | 69篇 |
2021年 | 50篇 |
2020年 | 70篇 |
2019年 | 65篇 |
2018年 | 39篇 |
2017年 | 43篇 |
2016年 | 68篇 |
2015年 | 78篇 |
2014年 | 90篇 |
2013年 | 102篇 |
2012年 | 144篇 |
2011年 | 139篇 |
2010年 | 101篇 |
2009年 | 95篇 |
2008年 | 102篇 |
2007年 | 83篇 |
2006年 | 93篇 |
2005年 | 54篇 |
2004年 | 61篇 |
2003年 | 44篇 |
2002年 | 31篇 |
2001年 | 21篇 |
2000年 | 30篇 |
1999年 | 18篇 |
1998年 | 26篇 |
1997年 | 22篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 14篇 |
1993年 | 21篇 |
1992年 | 23篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 13篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
排序方式: 共有1986条查询结果,搜索用时 0 毫秒
111.
112.
113.
114.
柱前衍生化高效液相色谱荧光检测法测定桑叶中的1-脱氧野尻霉素 总被引:10,自引:0,他引:10
建立了芴甲氧酰氯(FMOC—Cl)柱前荧光衍生一高效液相色谱法测定桑叶中1-脱氧野尻霉素(DNJ)的方法。桑叶经0.05mol/L,盐酸提取,在pH8.5的硼酸盐缓冲溶液条件下,DNJ反应生成荧光产物,然后用高效液相色谱-荧光检测器测定。流动相为乙腈-0.1%醋酸(55:45,V/V)。线性范围为0.567~34mg/L(相关系数r=0.9999);检出限为0.03mg/L。实验测得桑叶中DNJ含量为0.24%;平均回收率为97.1%,RSD为1.35%(n=6)。 相似文献
115.
116.
117.
118.
DENG SuiPing OUYANG JianMing XIE YuShan XING FeiYue Institute of Biomineralization Lithiasis Research Jinan University Guangzhou China 《中国科学B辑(英文版)》2008,51(1):25-30
The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett (LB) films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate (COM) were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine (DPPC) LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size (5-20 μm) increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level. 相似文献
119.
120.
Accelerated Simulation Study of Space Charge Effects in Quadrupole Ion Traps Using GPU Techniques 总被引:1,自引:0,他引:1
Xingchuang Xiong Wei Xu Xiang Fang Yulin Deng Zheng Ouyang 《Journal of the American Society for Mass Spectrometry》2012,23(10):1799-1807
Space charge effects play important roles in the performance of various types of mass analyzers. Simulation of space charge effects is often limited by the computation capability. In this study, we evaluate the method of using graphics processing unit (GPU) to accelerate ion trajectory simulation. Simulation using GPU has been compared with multi-core central processing unit (CPU), and an acceleration of about 390 times have been obtained using a single computer for simulation of up to 105 ions in quadrupole ion traps. Characteristics of trapped ions can be investigated at detailed levels within a reasonable simulation time. Space charge effects on the trapping capacities of linear and 3D ion traps, ion cloud shapes, ion motion frequency shift, mass spectrum peak coalescence effects between two ion clouds of close m/z are studied with the ion trajectory simulation using GPU. 相似文献