全文获取类型
收费全文 | 1425篇 |
免费 | 47篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 25篇 |
综合类 | 1篇 |
化学工业 | 409篇 |
金属工艺 | 16篇 |
机械仪表 | 25篇 |
建筑科学 | 33篇 |
矿业工程 | 7篇 |
能源动力 | 22篇 |
轻工业 | 67篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 105篇 |
一般工业技术 | 252篇 |
冶金工业 | 238篇 |
原子能技术 | 11篇 |
自动化技术 | 253篇 |
出版年
2023年 | 11篇 |
2022年 | 38篇 |
2021年 | 29篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 23篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 100篇 |
2012年 | 61篇 |
2011年 | 70篇 |
2010年 | 46篇 |
2009年 | 50篇 |
2008年 | 33篇 |
2007年 | 30篇 |
2006年 | 55篇 |
2005年 | 47篇 |
2004年 | 51篇 |
2003年 | 49篇 |
2002年 | 35篇 |
2001年 | 17篇 |
2000年 | 22篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 24篇 |
1995年 | 16篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 24篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 17篇 |
1985年 | 15篇 |
1982年 | 19篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1976年 | 25篇 |
1975年 | 16篇 |
1974年 | 21篇 |
1973年 | 14篇 |
1970年 | 10篇 |
排序方式: 共有1476条查询结果,搜索用时 8 毫秒
131.
Stanley HE Buldyrev SV Franzese G Giovambattista N Starr FW 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2005,363(1827):509-523
The thermodynamic behaviour of water seems to be related to static heterogeneities. These static heterogeneities are related to the local structure of water molecules and, when properly characterized, may offer an economical explanation of thermodynamic data. 'What matters' most in determining some of the unusual properties of liquid water may be the fact that the local geometry of the liquid molecules is not spherical or oblong, but rather tetrahedral. In respect to static heterogeneities, this local geometry is critical. The dynamic behaviour of water seems to be related to dynamic heterogeneities, which seem to explain the dynamics of supercooled liquid water well. 相似文献
132.
Seong Jin Park Pavan Suri Eugene Olevsky Randall M. German 《Journal of the American Ceramic Society》2009,92(7):1410-1413
The classical master sintering curve (MSC) is derived from empirical sintering model and is applicable over a range of heating rates and temperatures. For simplicity, the MSC approach was modified by assuming one dominant densification mechanism to evaluate and predict densification response. However, the concept of MSC can be extended well beyond the original formulation or the subsequent simplifications. To this effect, generalized formulations are proposed based on several constitutive equations including both grain growth and densification. These formulations can be used very effectively to obtain material properties that in turn can be used in finite-element method to improve the accuracy of the simulations. 相似文献
133.
134.
Study of self-stratifying compositions 总被引:2,自引:0,他引:2
Helena Kuczyńska Ewa Langer Elżbieta Kamińska-Tarnawska Dmitry A. Kulikov Eugene A. Indeikin 《Journal of Coatings Technology and Research》2009,6(3):345-352
Paint applied as a single layer, and its spontaneous separation to form a primer and a top coat, is one of the newest concepts
of the effective and economical application of two layers in one step. The influence of the molecular weight of epoxy oligomer
and acrylic polymer and their ratio on self-stratification was investigated. The degree of stratification depending on molecular
weight and their mutual ratio was determined using ATR-FTIR spectroscopy, differential scanning calorimetry, microscopy techniques,
adhesion tests, and surface tension measurements. Phase separation and self-stratification of two-component homogenous mixtures
were followed using FTIR technique and surface tension measurements. As a result of these investigations, optimal oligomeric/polymeric
composition was selected. The obtained coating system showed good mechanical properties, gloss, and interlayer adhesion. 相似文献
135.
Seok-Woo Lee Eugene Kim Sang-Soo Han Hye Sun Lee Duk-Chul Yun Kyoung Moon Lim Myoung-Su Yang Chang-Dong Kim 《Electron Device Letters, IEEE》2003,24(3):174-176
We have investigated the electrical characteristics of gate oxide films deposited by plasma enhanced chemical vapor deposition (PECVD) with respect to gate oxide integrity (GOI) and its reliability. In the investigation, post-annealed gate oxide was compared with as-deposited oxide. It was shown that the characteristics of GOI strongly depended on the charge trapping characteristics and deep level interface states generation under FN stress, which was remarkably improved by post-annealing after gate oxide deposition. Improved FN stress and hot carrier stress reliability of CMOS devices implemented on the glass substrate are also discussed. 相似文献
136.
A series of collagen–polypyrrole hybrid materials have been synthesized by the chemical polymerization of pyrrole using FeCl3 as initiator in the presence of soluble collagen. The black color of the resulting materials indicates the presence of polypyrrole while collagen was verified by amino acid analysis of the hybrids. Collagen incorporation into the hybrid was found to be a function of pyrrole concentration used in the polymerization. When the concentrationof pyrrole was high, the collagen loading was low and vice versa. This inverse relationship was also found in the hybrids' electrical conductivity. A 26% collagen content in the hybrid gave a conductivity of 1.4 S cm?1 while a 4% collagen gave a higher value of 62.4 S cm?1. Thermogravimetric data suggest that the two polymers exist in the hybrid as a blend. The nature of the interaction of the components in the hybrid is believed to be strong since collagen could not be extracted despite denaturation with sodium dodecylsulfate. 相似文献
137.
High yields of cyclic oligomeric carbonates can be prepared using an amine-catalyzed reaction of bisphenol A–bischloroformate. We have studied the mechanistic aspets of this carbonate macrocyclization by the isolated study of key chemical events. Using stopped-flow FT-IR spectroscopy, we have found that the rate of carbonate formation between the intermediate acyl ammonium salt and 4-isopropylphenol is the same for the acyl ammonium salt derived from tri-n-butylamine, triethylamine and diethylmethylamine. Previously, we found that conversion of acyl ammonium salt to urethane was also insensitive to amine structure while the formation of acyl ammonium salt is profoundly dependent on amine structure. These results are consistent with a mechanism in which the selectivity toward macrocyclization versus linear oligomer or high polymer formation is related to acyl ammonium salt concentration. 相似文献
138.
139.
Contends that A. E. Shapiro and J. G. Wiggins's (see record 1994-31325-001) proposal to convert the PhD in psychology to a Doctor of Psychology is misguided. Taylor argues that the PhD should be retained, while providing for the necessary acknowledgment of specialized training through credentialing at the postdoctoral level. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
140.
Approximately zero-order release of ephedrine hydrochloride and procaine hydrochloride was obtained from multiple-layered matrixes of hydrogenated castor oil containing various concentrations of the medicinal compound in each layer. For the examples presented, an apparent zero-order release was observed for the release of 50-90% of the medicinal compound. 相似文献