全文获取类型
收费全文 | 173篇 |
免费 | 20篇 |
专业分类
化学 | 138篇 |
晶体学 | 5篇 |
力学 | 7篇 |
数学 | 24篇 |
物理学 | 19篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 12篇 |
2012年 | 21篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 14篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1936年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有193条查询结果,搜索用时 15 毫秒
81.
During bacterial chemotaxis, the histidine autokinase CheA interacts with the chemotaxis receptors with the help of the coupling protein CheW. This interaction is typical of many macromolecular complexes where protein-protein interactions play an important role. In this case, a relatively small protein, CheW, becomes part of a much larger complex. Here we describe a new method to map the residues at a protein-protein interface for macromolecular complexes of molecular weight greater than 100 kD. 相似文献
82.
Enhancing Energetic Properties and Sensitivity by Incorporating Amino and Nitramino Groups into a 1,2,4‐Oxadiazole Building Block
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Yongxing Tang Dr. Haixiang Gao Dr. Lauren A. Mitchell Dr. Damon A. Parrish Prof. Dr. Jean'ne M. Shreeve 《Angewandte Chemie (International ed. in English)》2016,55(3):1147-1150
A single nitrogen‐rich heterocyclic ring with many energetic groups is expected to exhibit excellent detonation performance. We report an effective approach for the synthesis of 3‐amino‐5‐nitramino‐1,2,4‐oxadiazole, which has nitramino and amino groups in the same building block. The single‐crystal X‐ray structure shows layered hydrogen‐bonding pairs as well as the presence of a water molecule which ensure insensitivity. Through incorporation of a cation, the hydrazinium or hydroxylammonium salts exhibit good energetic performance and acceptable sensitivities. 相似文献
83.
Potassium 4,4′‐Bis(dinitromethyl)‐3,3′‐azofurazanate: A Highly Energetic 3D Metal–Organic Framework as a Promising Primary Explosive
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Yongxing Tang Dr. Chunlin He Dr. Lauren A. Mitchell Dr. Damon A. Parrish Prof. Dr. Jean'ne M. Shreeve 《Angewandte Chemie (International ed. in English)》2016,55(18):5565-5567
Environmentally acceptable alternatives to toxic lead‐based primary explosives are becoming increasingly important for energetic materials. In this study, potassium 4,4′‐bis(dinitromethyl)‐3,3′‐azofurazanate, comprising two dinitromethyl groups and an azofurazan moiety, was synthesized and isolated as a new energetic 3D metal–organic framework (MOF). Several attractive properties, including a density of 2.039 g cm?3, a decomposition temperature of 229 °C, a detonation velocity of 8138 m s?1, a detonation pressure of 30.1 GPa, an impact sensitivity of 2 J, and friction sensitivity of 20 N make 4 a good candidate as a green primary explosive. 相似文献
84.
Ohne Zusammenfassung 相似文献
85.
Richard M. Burton David C. Dellinger William W. Damon Eric A. Pfeiffer 《The Journal of the Operational Research Society》1978,29(7):633-641
This paper describes a research team's effort in which a formal mathematical model played an integrating and coordinating role for a multidisciplinary team which included operational researchers, economists, nurses, social workers, social scientists and psychiatrists. It is an interpretative history of the OARS project, its development and results which emphasizes the role of the formal model in the conduct of the project.This is an application of Operational Research to a significant social problem which also suggests an important role for Operational Researchers in Health Care Planning and Management Teams. 相似文献
86.
Yingxin Xiao Ronald J. Voll Damon R. Billodeaux Frank R. Fronczek Ezzat S. Younathan 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):379-382
Two polymorphs of the title compound, (4R,5R,6R,7R)‐4,7‐bis(hydroxymethyl)‐1,3‐dioxepane‐5,6‐diol, C7H14O6, both have Z′ = 2 at 100 K, and differ in their hydrogen‐bonding patterns. The sodium iodide complex, NaI·C7H14O6, is isomorphous with the NaCl complex, and has the mannitol, cation and anion all lying on twofold axes. The dioxepane rings of all three molecules are in the twist‐chair conformation. 相似文献
87.
88.
Damon Centola 《Journal of statistical physics》2013,151(1-2):238-253
Collective behaviors often spread via the self-reinforcing dynamics of critical mass. In collective behaviors with strongly self-reinforcing dynamics, incentives to participate increase with the number of participants, such that incentives are highest when the full population has adopted the behavior. By contrast, when collective behaviors have weakly self-reinforcing dynamics, incentives to participate “peak out” early, leaving a residual fraction of non-participants. In systems of collective action, this residual fraction constitutes free riders, who enjoy the collective good without contributing anything themselves. This “free rider problem” has given rise to a research tradition in collective action that shows how free riding can be eliminated by increasing the incentives for participation, and thereby making cooperation strongly self-reinforcing. However, we show that when the incentives to participate have weakly self-reinforcing dynamics, which allow free riders, collective behaviors will have significantly greater long term stability than when the incentives have strongly self-reinforcing dynamics leading to full participation. 相似文献
89.
Giuseppe Grassi Damon A. Miller 《Communications in Nonlinear Science & Numerical Simulation》2012,17(4):1824-1830
This paper provides a contribution to the topic of full state hybrid projective synchronization (FSHPS) by introducing an observer-based approach that enables synchronization to be achieved via a scalar synchronizing signal. The method is based on a theorem that assures dead-beat synchronization (i.e., exact synchronization in finite time) to a wide class of discrete-time chaotic (hyperchaotic) systems. Two examples, involving the hyperchaotic Grassi-Miller map and the hyperchaotic double scroll map, show that FSHPS can be effectively achieved in finite time using a scalar synchronizing signal only. 相似文献
90.
The sequential bond energies of Ca(2+)(H(2)O)(x) complexes, where x = 1-8, are measured by threshold collision-induced dissociation (TCID) in a guided ion beam tandem mass spectrometer. From an electrospray ionization source that produces an initial distribution of Ca(2+)(H(2)O)(x) complexes where x = 6-8, complexes down to x = 2 are formed using an in-source fragmentation technique. Ca(2+)(H(2)O) cannot be formed in this source because charge separation into CaOH(+) and H(3)O(+) is a lower energy pathway than simple water loss from Ca(2+)(H(2)O)(2). The kinetic energy dependent cross sections for dissociation of Ca(2+)(H(2)O)(x) complexes, where x = 2-9, are examined over a wide energy range to monitor all dissociation products and are modeled to obtain 0 and 298 K binding energies. Analysis of both primary and secondary water molecule losses from each sized complex provides thermochemistry for the sequential hydration energies of Ca(2+) for x = 1-8 and the first experimental values for x = 1-4. Additionally, the thermodynamic onsets leading to the charge separation products from Ca(2+)(H(2)O)(2) and Ca(2+)(H(2)O)(3) are determined for the first time. Our experimental results for x = 1-6 agree well with previously calculated binding enthalpies as well as quantum chemical calculations performed here. Agreement for x = 1 is improved when the basis set on calcium includes core correlation. 相似文献