全文获取类型
收费全文 | 1799篇 |
免费 | 100篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 24篇 |
化学工业 | 422篇 |
金属工艺 | 6篇 |
机械仪表 | 33篇 |
建筑科学 | 90篇 |
矿业工程 | 1篇 |
能源动力 | 47篇 |
轻工业 | 179篇 |
水利工程 | 25篇 |
石油天然气 | 1篇 |
无线电 | 158篇 |
一般工业技术 | 324篇 |
冶金工业 | 244篇 |
原子能技术 | 27篇 |
自动化技术 | 321篇 |
出版年
2023年 | 14篇 |
2022年 | 100篇 |
2021年 | 103篇 |
2020年 | 62篇 |
2019年 | 52篇 |
2018年 | 65篇 |
2017年 | 48篇 |
2016年 | 69篇 |
2015年 | 49篇 |
2014年 | 66篇 |
2013年 | 109篇 |
2012年 | 99篇 |
2011年 | 137篇 |
2010年 | 84篇 |
2009年 | 94篇 |
2008年 | 90篇 |
2007年 | 85篇 |
2006年 | 62篇 |
2005年 | 59篇 |
2004年 | 54篇 |
2003年 | 34篇 |
2002年 | 32篇 |
2001年 | 22篇 |
2000年 | 20篇 |
1999年 | 20篇 |
1998年 | 54篇 |
1997年 | 38篇 |
1996年 | 27篇 |
1995年 | 12篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有1902条查询结果,搜索用时 15 毫秒
1.
Fabiana Piscitelli Roberto Coccurello Antonio Totaro Alessandro Leuti Giacomo Giacovazzo Roberta Verde Emanuela Rossi Michele Podaliri Vulpiani Nicola Ferri Roberto Giacominelli Stuffler Vincenzo Di Marzo Sergio Oddi Tiziana Bisogno Mauro Maccarrone 《European Journal of Lipid Science and Technology》2019,121(10)
2.
3.
4.
The size effects on the mean values of the mechanical properties of condensed matter and on the related variances are analysed by means of a unified approach based on the multiscale character of energy dissipation. In particular, the scaling law for fragmentation energy density is obtained taking into account the self-similarity of fragments. It is based on a generalization of the three classical comminution laws that has been performed to evaluate the energy dissipation, computing volume and surface area of the particles for one- two- and three-dimensional fragmented objects. The result is general and can be applied to different fractal energy dissipation mechanisms, e.g., plasticity. Based on this approach, the scaling laws for mean and standard deviation values of the main mechanical properties of materials can be derived, like Young's and shear elastic moduli, ultimate normal and shear stresses and strains, fracture energy and toughness. 相似文献
5.
IC Lavery F Lopez-Kostner VW Fazio M Fernandez-Martin JW Milsom JM Church 《Canadian Metallurgical Quarterly》1997,122(4):779-84; discussion 784-5
BACKGROUND: The goal of this study was to compare patterns of recurrence and long-term outcome after sphincter-saving procedures (SSPs) and abdominoperineal resection (APR) in patients with tumors located in the lower third of the rectum. METHODS: We reviewed the charts of 1001 patients operated on for primary rectal adenocarcinoma between 1980 and 1991. All patients with tumors located between 5 and 7 cm from the anal verge and treated with curative intent were included. RESULTS: Of the 261 patients who met our criteria, 162 had undergone SSP and 99 had undergone APR. The local recurrence rates for SSP and APR were 8% and 11%, respectively (p = 0.41), and the distant metastases rates were 23% and 28%, respectively (p = 0.35). Recurrence and distant metastases rates for SSP and APR, respectively, did not differ by TNM classification: state I, 10% versus 9% (p = 0.9); stage II, 25% versus 43% (p = 0.13); and stage III, 56% versus 57% (p = 0.92). Five-year disease-free survival rates for SSP and APR patients were 70.5% and 62.3%, respectively (p = 0.2). CONCLUSIONS: Tumors in the lower third of the rectum can be treated with sphincter-saving procedures without compromising the chance of cure. 相似文献
6.
A computer model was extended and adapted to simulate the hygrothermal behavior of building envelope-wood components. The model was used to predict moisture movement in wood planks forming the decks of nonvented flat roofs insulated with cellulose. The gradient of water potential was considered as the driving force for moisture movement in wood. The model required the determination of convective heat- and mass-transfer coefficients, the sorption curves, the effective water conductivity for different wood species, and the hygrothermal conditions within the assembly to characterize the mass-conservation equation. Once these parameters were integrated in the computer model, this approach was then validated by carrying a simulation of the drying process of wood planks using experimental data from a large-scale test. 相似文献
7.
8.
Statistical machine translation systems are usually trained on large amounts of bilingual text (used to learn a translation
model), and also large amounts of monolingual text in the target language (used to train a language model). In this article
we explore the use of semi-supervised model adaptation methods for the effective use of monolingual data from the source language
in order to improve translation quality. We propose several algorithms with this aim, and present the strengths and weaknesses
of each one. We present detailed experimental evaluations on the French–English EuroParl data set and on data from the NIST
Chinese–English large-data track. We show a significant improvement in translation quality on both tasks. 相似文献
9.
The interactivity effect in multimedia learning 总被引:4,自引:1,他引:3
10.
In comparing our calculated exciton energies with those obtained from pseudopotential calculations (Ref. 27) and from a previous
tight binding calculation (Ref. 30), we stated that the differences between the three semi-empirical calculations arise because
of different treatment of the nanocrystal surfaces. This appears not to be correct. Subsequent calculations with variable
Si-H parameters have shown that the band gap is actually rather insensitive to the actual value of these. Instead, the important
feature appears to be the overall quality of the bulk band structure parameterization. References 27 and 30 use more extensive
and higher quality empirical parameterizations for bulk Si than the sp3s∗ model used by us. Repeating our time dependent calculations with an improved sp3d5 parameterization results in similar values to those of Refs. 27 and 30 for the exciton energies.1 The agreement of the sp3s∗ values with experimental photoluminescence energies (Fig. 7) cannot, therefore, be regarded as well understood at this
time.1,2 相似文献