全文获取类型
收费全文 | 443篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
化学 | 292篇 |
晶体学 | 6篇 |
力学 | 20篇 |
数学 | 40篇 |
物理学 | 105篇 |
出版年
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 15篇 |
2020年 | 16篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 17篇 |
2014年 | 25篇 |
2013年 | 35篇 |
2012年 | 33篇 |
2011年 | 31篇 |
2010年 | 20篇 |
2009年 | 20篇 |
2008年 | 25篇 |
2007年 | 18篇 |
2006年 | 11篇 |
2005年 | 19篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 7篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有463条查询结果,搜索用时 13 毫秒
11.
Rajendran Duraisamy Ramalingam Ganapathy Sundaram Esakkimuthu Jawahar Paulraj Sivakumar Vaithilingam Mahian Omid Bellos Evangelos 《Journal of Thermal Analysis and Calorimetry》2020,140(1):33-51
Journal of Thermal Analysis and Calorimetry - The solar collector (reflector and receiver) is the primary device being used in the concentrating solar power technologies for tapping the solar... 相似文献
12.
13.
This Letter is concerned with stability analysis problem for uncertain stochastic neural networks with discrete interval and distributed time-varying delays. The parameter uncertainties are assumed to be norm bounded and the delay is assumed to be time-varying and belong to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. Based on the Lyapunov-Krasovskii functional and stochastic stability theory, delay-interval dependent stability criteria are obtained in terms of linear matrix inequalities. Some stability criteria are formulated by means of the feasibility of a linear matrix inequality (LMI) and by introducing some free-weighting matrices. Finally, two numerical examples are provided to demonstrate the less conservatism and effectiveness of the proposed LMI conditions. 相似文献
14.
T. Kanna M. Lakshmanan 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):249-254
Soliton interactions in systems modelled by coupled nonlinear Schr?dinger (CNLS) equations and encountered in phenomena such
as wave propagation in optical fibers and photorefractive media possess unusual features: shape changing intensity redistributions,
amplitude dependent phase shifts and relative separation distances. We demonstrate these properties in the case of integrable
2-CNLS equations. As a simple example, we consider the stationary two-soliton solution which is equivalent to the so-called
partially coherent soliton (PCS) solution discussed much in the recent literature.
Received 1st October 2001 / Received in final form 4 February 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: lakshman@bdu.ernet.in 相似文献
15.
Aequationes mathematicae - The Hyers-Ulam stability of the iterative equation $$f^n=F$$ for continuous functions F was studied under the assumptions that F is a homeomorphism on its range, and the... 相似文献
16.
Improved results on robust stability of neutral systems with mixed time-varying delays and nonlinear perturbations 总被引:1,自引:0,他引:1
This paper considers the problem of robust stability of neutral systems with mixed time-varying delays and nonlinear perturbations. Two type uncertainties such as nonlinear time-varying parameter perturbations and norm-bounded uncertainties have been discussed. Based on the new Lyapunov–Krasovskii functional with triple integral terms, some integral inequalities and convex combination technique, a new delay-dependent stability criterion for the system is established in terms of linear matrix inequalities (LMIs). Finally, four numerical examples are given to illustrate the effectiveness and an improvement over some existing results in the literature with the proposed results. 相似文献
17.
The separation of the enantiomers of flurbiprofen on an amylose-derived chiral stationary phase, Chiralpak AD-H, by supercritical fluid chromatography (SFC) under both linear and non-linear conditions is studied. Pulse injections were implemented using supercritical CO2modified with methanol as a mobile phase at a temperature of 30 °C. At linear conditions, the isotherm is determined directly from the chromatogram. Under overload conditions, the elution profiles were described by competitive Langmuir and bi-Langmuir isotherm. Isotherm parameters were estimated using the inverse method and the effects of operation variables such as pressure and modifier composition were studied. The value of selectivity is from 1.9 to 2.1 while the value of resolution is from 5.3 to 11.8. The number of theoretical plates is always greater than 5000 indicating high efficiency of SFC. 相似文献
18.
Sippel KH Genis C Govindasamy L Agbandje-McKenna M Kiddle JJ Tripp BC McKenna R 《The journal of physical chemistry letters》2010,1(19):2898-2902
Thioxolone acts as a prodrug in the presence of carbonic anhydrase II (CA II), whereby the molecule is cleaved by thioester hydrolysis to the carbonic anhydrase inhibitor, 4-mercaptobenzene-1,3-diol (TH0). Thioxolone was soaked into the proton transfer mutant H64A of CA II in an effort to capture a reaction intermediate via X-ray crystallography. Structure determination of the 1.2 ? resolution data revealed the TH0 had been modified to a 4,4'-disulfanediyldibenzene-1,3-diol, a product of crystallization conditions, and a zinc ligated 2,4-dihydroxybenzenesulfenic acid, most likely induced by radiation damage. Neither ligand was likely a result of an enzymatic mechanism. 相似文献
19.
20.
Gunasekaran Manonmani Lakshmanan Sandhiya Kittusamy Senthilkumar 《International journal of quantum chemistry》2020,120(11):e26182
The hydrolysis of sulfonylamine (HNSO2) results in the formation of sulfuric acid along with ammonia, and is of significant interest due to their negative impact on environment and life on Earth. The formation of H2SO4 through the reaction of HNSO2 with (H2O)2-4 has been studied using high level electronic structure calculations. This hydrolysis reaction is a step-wise process, in the first step a H-atom from H2O is transferred to the N-atom of HNSO2 which results in the formation of NH2, and in the next step, H2SO4, NH3 and water molecule(s) are formed. The results show that the energy barrier associated with the formation of intermediates and product complexes is reduced by 7 to 10 kcal/mol when the number of water molecules is increased from 2 to 4. The rate constant was calculated using canonical variational transition state theory with small curvature tunneling correction over the temperature range of 200 to 1000 K. At 298 K, the calculated rate constant for the formation of intermediate in the first step is 2.24 × 10−16, 1.03 × 10−12, and 2.10 × 10−11 cm3 mol−1 s−1, respectively, for the reaction with water dimer, trimer and tetramer. The calculated enthalpy and free energy show that the reaction corresponding to the formation of H2SO4 is highly exothermic and exoergic in nature. 相似文献