全文获取类型
收费全文 | 146篇 |
免费 | 5篇 |
专业分类
化学 | 112篇 |
力学 | 3篇 |
数学 | 8篇 |
物理学 | 28篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 14篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 5篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1966年 | 2篇 |
1939年 | 2篇 |
1936年 | 1篇 |
1935年 | 3篇 |
1932年 | 1篇 |
1931年 | 3篇 |
1930年 | 3篇 |
1928年 | 2篇 |
排序方式: 共有151条查询结果,搜索用时 31 毫秒
121.
Elizabeth Stubbs Elizabeth Laskowski Phillip Conor Daniel Alves Heinze Dylan Karis 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(4):228-235
A series of poly(ethylene glycol) monomethyl ether-block-poly(2-(dimethylamino)ethyl methacrylate) (mPEG-b-PDMAEMA) diblock copolymers were synthesized using atom transfer radical polymerization to achieve controlled polymer molecular weight and narrow molecular weight distribution. The thermoresponsive properties of the mPEG-b-PDMAEMA diblock copolymers in aqueous buffered solutions were determined using UV-Visible spectroscopy and dynamic light scattering. The cloud point, a soluble-to-insoluble transition, was observed for all mPEG-b-PDMAEMA diblock copolymer solutions. Increasing either the mPEG or PDMAEMA molecular weight resulted in a decrease in observed cloud points as a function of pH and polymer concentration. Changing the mPEG molecular weight determined whether a second, higher temperature, thermal transition was observed as a function of pH and polymer concentration. Controlling the thermoresponsive properties of mPEG-b-PDMAEMA diblock copolymers through polymer composition, concentration, and pH enables the tailoring of these copolymers for applications ranging from non-viral gene delivery to use as a strengthening agent in paper. 相似文献
122.
123.
Hang Li Jinyu Hu Haochen Wei Dr. Peter S. Solomon Dr. Keith A. Stubbs Dr. Yit-Heng Chooi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(66):15062-15066
The aldol reaction is one of the most fundamental stereocontrolled carbon–carbon bond-forming reactions and is mainly catalyzed by aldolases in nature. Despite the fact that the aldol reaction has been widely proposed to be involved in fungal secondary metabolite biosynthesis, a dedicated aldolase that catalyzes stereoselective aldol reactions has only rarely been reported in fungi. Herein, we activated a cryptic polyketide biosynthetic gene cluster that was upregulated in the fungal wheat pathogen Parastagonospora nodorum during plant infection; this resulted in the production of the phytotoxic stemphyloxin II ( 1 ). Through heterologous reconstruction of the biosynthetic pathway and in vitro assay by using cell-free lysate from Aspergillus nidulans, we demonstrated that a berberine bridge enzyme (BBE)-like protein SthB catalyzes an intramolecular aldol reaction to establish the bridged tricyclo[6.2.2.02,7]dodecane skeleton in the post-assembly tailoring step. The characterization of SthB as an aldolase enriches the catalytic toolbox of classic reactions and the functional diversities of the BBE superfamily of enzymes. 相似文献
124.
K. Sarló A. Gronover F. Türk G. D. Elsdon J. R. Stubbs R. Strohecker G. M. Moir D. R. Wood E. T. Illing A. E. Fletcher G. W. Monier-Williams W. Müller V. Gerber H. T. Gebhardt H. H. Sommer C. A. Elvehjem C. W. Lindow Ch. Porcher G. Denigès A. Sabatié C. L. Hinton T. Macara J. M. Kolthoff C. I. Kruisheer O. Laxa 《Analytical and bioanalytical chemistry》1932,88(11-12):450-459
125.
The problem of using measured modal parameters to detect and locate damage in structures made of fiberreinforced composites
is investigated. Recent work in this area using modal sensitivity equations is used in conjunction with internal-state variable
constitutive theory to derive a set of damage-detection equations which are used to predict, from changes in measured modal
parameters, the current value of the internal-state variables in each finite element. The value of the internal-state variable
determines the extent of damage at a given location. Numerical examples involving damaged composite beams are used to demonstrate
the capability of the theory to predict the exact location and the severity of damage. To provide experimental evidence to
support the theory, mechanical and modal tests are performed on a [0,903]
s
laminated composite beam in the undamaged state and in three additional states of progressive damage. At each stage of damage,
edge replications are taken to determine the crack density along the length of the beam. The predicted values of the internal-state
variables, obtained from the modalsensitivity equations using measured modal information, are compared with the values of
the internal-state variables obtained from crack-density measurements along the length of the beam. Good agreement between
the predicted and the measured values is found. 相似文献
126.
Inhibiting an Epoxide Hydrolase Virulence Factor from Pseudomonas aeruginosa Protects CFTR 下载免费PDF全文
Dr. Christopher D. Bahl Kelli L. Hvorecny Prof. Dr. Jennifer M. Bomberger Prof. Dr. Bruce A. Stanton Prof. Dr. Bruce D. Hammock Dr. Christophe Morisseau Prof. Dr. Dean R. Madden 《Angewandte Chemie (International ed. in English)》2015,54(34):9881-9885
Opportunistic pathogens exploit diverse strategies to sabotage host defenses. Pseudomonas aeruginosa secretes the CFTR inhibitory factor Cif and thus triggers loss of CFTR, an ion channel required for airway mucociliary defense. However, the mechanism of action of Cif has remained unclear. It catalyzes epoxide hydrolysis, but there is no known role for natural epoxides in CFTR regulation. It was demonstrated that the hydrolase activity of Cif is strictly required for its effects on CFTR. A small‐molecule inhibitor that protects this key component of the mucociliary defense system was also uncovered. These results provide a basis for targeting the distinctive virulence chemistry of Cif and suggest an unanticipated role of physiological epoxides in intracellular protein trafficking. 相似文献
127.
128.
Jeffrey M. Stubbs Donald C. Sundberg 《Journal of Polymer Science.Polymer Physics》2011,49(22):1583-1589
Many composite polymer latices are produced with nonequilibrium particle morphologies and these can be prone to structural changes with the time of storage. Here we report on the use of coalescing agents, and separately thermal annealing to follow the morphology changes with aging time. Two coalescing agents with very different water solubilities were used to plasticize the latex polymers. During months of storage time the polymer particles were analyzed via differential scanning calorimetry and transmission electron microscopy. A parallel set of aging experiments were carried out for the same latices where the change agent was simple thermal annealing. Both latex and dry polymer samples were annealed at temperatures above 100 °C and for various periods of time. Both sets of experiments lead to the conclusion that when the aging temperature is at or above the effective glass transition temperature (taking into account solvent plasticization) of the glassiest of the polymers in a two‐component latex, morphological change can be rather fast and easily characterized. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1583–1589, 2011 相似文献
129.
K. Eble H. Pfeiffers K. Jeschki W. Reidemeister G. D. Edson J. R. Stubbs G. D. Elsdon A. Pawletta Dagmar von Wentzky Petersheyde W. Leithe W. G. Lichatschew Arnaldo Foschini Bruno Rossi E. Letzig G. A. Richardson N. P. Tarassuk Giulio Buogo Lagrangé-Francès O. Mezger J. Umbrecht F. Kopatscheck und A. Foschini 《Fresenius' Journal of Analytical Chemistry》1935,103(1-2):64-70
Ohne Zusammenfassung 相似文献
130.