全文获取类型
收费全文 | 314篇 |
免费 | 25篇 |
国内免费 | 1篇 |
专业分类
化学 | 301篇 |
力学 | 3篇 |
数学 | 16篇 |
物理学 | 20篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 15篇 |
2015年 | 19篇 |
2014年 | 14篇 |
2013年 | 12篇 |
2012年 | 24篇 |
2011年 | 22篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 22篇 |
2007年 | 22篇 |
2006年 | 22篇 |
2005年 | 12篇 |
2004年 | 15篇 |
2003年 | 15篇 |
2002年 | 18篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1966年 | 3篇 |
排序方式: 共有340条查询结果,搜索用时 15 毫秒
101.
102.
103.
We report on the deformation of an air-water surface with a totally reflected low-power laser beam, inducing a convex mirror effect on the beam propagation. This bending is stronger close to the critical angle and depends on the polarization of the laser light. A model, leading to a simple dependence between the Goos-H?nchen shift and the radius of curvature of the interface, supports these observations. Bendings with radius of curvature as low as 0.10 m are demonstrated. 相似文献
104.
Dr. Rock J. Mancini Janine K. Tom Prof. Aaron P. Esser‐Kahn 《Angewandte Chemie (International ed. in English)》2014,53(1):189-192
We report increased stimulation of dendritic cells via heterodimers of immunostimulants formed at a discrete molecular distance. Many vaccines present spatially organized agonists to immune cell receptors. These receptors cluster suggesting that signaling is increased by spatial organization and receptor proximity, but this has not been directly tested for multiple, unique receptors. In this study we probe the spatial aspect of immune cell activation using heterodimers of two covalently attached immunostimulants. 相似文献
105.
Tutita M. Casa Juliana R. MacSwan Kara E. LaMonica Madelyn W. Colonnese Janine M. Firmender 《School science and mathematics》2019,119(4):176-189
Curriculum guidelines and professional organizations’ recommendations lack details about how often and how much students should write in mathematics and what characteristics should define their writing. This study presents an analytic framework that addresses how often students are prompted in student mathematics books to write, how much they may be encouraged to write, and the characteristics of the writing prompts. Consequently, 2,095 writing prompts in student books across 10 comprehensive Grade 3 resources were analyzed. Findings indicate a marked variation in how often and how much students are positioned to write. Most prompts have students explain what they did to solve a problem and why about number concepts, with most pressing for procedures. The greatest percentage of prompts had students write about their own solutions and do not urge them to include specific writing features. 相似文献
106.
Nicolas Gillaizeau-Simonian Dr. Etienne Barde Dr. Amandine Guérinot Prof. Janine Cossy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4004-4008
A cobalt-catalyzed 1,4-aryl migration/disulfonylation cascade applied to α-bromo N-sulfonyl amides was developed. The reaction was highly chemoselective, allowing the preparation of α-aryl amides possessing a variety of functional groups. The method was used as the key step to synthesize an alkaloid, (±)-deoxyeseroline. Mechanistic investigations suggest a radical process. 相似文献
107.
108.
109.
In an effort to develop sensitive nanoscale devices for chemical and biological sensing, we have examined, using liquid gating, the conductance of semiconducting single-walled carbon nanotube-based field-effect transistors (SWCNT-FETs) in the presence of redox mediators. As examples, redox couples K3Fe(CN)6/K4Fe(CN)6 and K2IrCl6/K3IrCl6 are shown to modulate the SWCNT-FET conductance in part through their influence via the electrolyte gate on the electrostatic potential of the solution, as described by Larrimore et al. (Nano Lett. 2006, 6, 3129-1333) and in part through electron transfer between the redox mediators and the nanotubes. In the latter case, the rate of electron transfer is determined by the difference in chemical potential between the redox mediator and the SWCNTs and by the concentrations of the oxidized and reduced forms of the redox couple. Furthermore, these devices can detect the activity of redox enzymes through their sensitivity to the change in oxidation state of the enzyme substrate. An example is given for the blue copper oxidase, Trametes versicolor laccase, in which the rate of change of the SWCNT device conductance is linearly proportional to the rate of oxidation of the substrate 10-(2-hydroxyethyl)phenoxazine, varied over 2 orders of magnitude by the laccase concentration in the picomolar range. The behavior described in this work provides a highly sensitive means with which to do chemical and biological sensing using SWCNTs that is different from the amperometric, capacitive, and field-effect type sensing methods previously described in the literature for this material. 相似文献
110.
Herlihy KP Nunes J Desimone JM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(16):8421-8426
Micrometer-sized monodisperse anisotropic polymer particles, with disk, rod, fenestrated hexagon (hexnut), and boomerang shapes, were synthesized using the particle replication in nonwetting templates (PRINT) process, and investigations were conducted on aqueous suspensions of these particles when subjected to alternating electric fields. A coplanar electrode configuration, with 1 to 2 mm electrode gaps (20-50 V ac, 0.5-5.0 kHz) was used, and the experiments were monitored with fluorescence microscopy. For all particle suspensions, the field brought about significant changes in the packing and orientation. Extensive particle chaining and packing were observed for the disk, rod, and hexnut suspensions. Because of the size and geometry of the boomerang particles, limited chaining was observed; however, the field triggered a change from random to a more ordered packing arrangement. 相似文献