全文获取类型
收费全文 | 836篇 |
免费 | 42篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 218篇 |
金属工艺 | 22篇 |
机械仪表 | 31篇 |
建筑科学 | 32篇 |
矿业工程 | 5篇 |
能源动力 | 39篇 |
轻工业 | 143篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
无线电 | 45篇 |
一般工业技术 | 120篇 |
冶金工业 | 49篇 |
原子能技术 | 3篇 |
自动化技术 | 157篇 |
出版年
2024年 | 3篇 |
2023年 | 9篇 |
2022年 | 29篇 |
2021年 | 29篇 |
2020年 | 26篇 |
2019年 | 22篇 |
2018年 | 31篇 |
2017年 | 34篇 |
2016年 | 34篇 |
2015年 | 21篇 |
2014年 | 43篇 |
2013年 | 67篇 |
2012年 | 64篇 |
2011年 | 67篇 |
2010年 | 37篇 |
2009年 | 39篇 |
2008年 | 51篇 |
2007年 | 39篇 |
2006年 | 32篇 |
2005年 | 25篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 11篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1971年 | 1篇 |
1958年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有879条查询结果,搜索用时 0 毫秒
71.
Renato Martins da Silva Bárbara Della Noce Camila Fernanda Waltero Evenilton Pessoa Costa Leonardo Araujo de Abreu Naftaly Wang’ombe Githaka Jorge Moraes Helga Fernandes Gomes Satoru Konnai Itabajara da Silva Vaz Jr. Kazuhiko Ohashi Carlos Logullo 《International journal of molecular sciences》2015,16(1):1821-1839
72.
Digeorgia da Silva André I. Reis Renato P. Ribas 《Microelectronics Reliability》2010,50(9-11):1223-1229
In digital CMOS circuits, parametric yield improvement may be achieved by reducing the variability of performance and power consumption of individual cell instances. Such improvement of variation robustness can be attained by evaluating parameter variation impact at gate level. Statistical characterization of logic gates are usually obtained by computationally expensive electrical simulations. An efficient gate delay variability estimation method is proposed for variability-aware design. The proposed method has been applied to different topologies (transistor network arrangements) and CMOS gates, and it has been compared to Monte Carlo simulations for data validation, resulting in computation time savings. 相似文献
73.
Riccardo Matera Simone Gabbanini Gina Rosalinda De Nicola Renato Iori Gianna Petrillo Luca Valgimigli 《Food chemistry》2012
The freeze-dried sprouts’ juice of Raphanus sativus (L.) cv. Sango was prepared and analysed for the first time. HPLC analysis of total isothiocyanates, after protein displacement, resulted in 77.8 ± 3.0 μmol/g of dry juice while GC–MS analysis of hexane and acetone extracts showed E- and Z-raphasatin (8.9 and 0.11 μmol/g, respectively) and sulforaphene (11.7 μmol/g), summing up to 20.7 ± 1.7 μmol/g of free isothiocyanates. Sprouts’ juice contained an unprecedented wealth of anthocyanins and a new fractionation methodology allowed us to isolate 34 mg/g of acylated anthocyanins (28.3 ± 1.9 μmol/g), belonging selectively to the cyanidin family. Analysis was performed by HPLC–PDA–ESI–MSn and extended to deacylated anthocyanins and aglycones, obtained, respectively, by alkaline and acid hydrolysis. This study identified 70 anthocyanins, 19 of which have never been described before and 32 of which are reported here in R. sativus for the first time. Sango radish sprouts are exceptional dietary sources of heath-promoting micronutrients. 相似文献
74.
Carlos Güntner Andrés González Renato Dos Reis Gabriel González Alvaro Vázquez Fernando Ferreira Patrick Moyna 《Journal of chemical ecology》1997,23(6):1651-1659
Macrosiphum euphorbiae, also known as the potato aphid, is a potato virus vector, associated with decreased tuber production. Feeding, toxicity, and reproductive effects of the major potato glycoalkaloids (α-chaconine and α-solanine), their common aglycone (solanidine), and a nonpotato glycoalkaloid (α-tomatine) and its aglycone (tomatidine) onM. euphorbiae were studied. As expected, neither α-chaconine nor α-solanine had a strong lethal effect on the aphid, but α-chaconine stimulated feeding at low concentrations. Both aglycones were deterrent and lethal at high concentrations and, like α-chaconine and α-tomatine, they delayed the appearance and decreased the number of nymphs. 相似文献
75.
Reports an error in the original article by G. P. Lombardo and R. Foschi (History of Psychology, 2003, 2, 123-142). In the reference list, several works by Pierre Janet were identified as being Paul Janet. The correct references are provided, where Paul Janet is identified by the initial P. and Pierre Janet is identified by the initials P. M. F.. (The following abstract of this article originally appeared in record 2003-03729-003.) Since the 1920s, the road to the acknowledgment of personality psychology as a field of scientific psychology that has individuality as its object began with the founding of the discipline by Gordon W. Allport. Historians of psychology have made serious attempts to reconstruct the cultural, political, institutional, and chronological beginnings of this field in America in the 20th century. In this literature, however, an important European tradition of psychological studies of personality that developed in France in the 2nd half of the 19th century has been overlooked. The aim of this article is to cast some light on this unexplored tradition of psychological personality studies and to discuss its influence on the development of the scientific study of personality in the United States. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
Renata Braga Araújo Guilherme Henrique Trielli Ferreira Gustavo Henrique Orair Wagner Meira Jr. Renato Antônio Celso Ferreira Dorgival Olavo Guedes Neto Mohammed Javeed Zaki 《International journal of parallel programming》2008,36(2):226-249
Analyzing gene expression patterns is becoming a highly relevant task in the Bioinformatics area. This analysis makes it possible
to determine the behavior patterns of genes under various conditions, a fundamental information for treating diseases, among
other applications. A recent advance in this area is the Tricluster algorithm, which is the first algorithm capable of determining
3D clusters (genes × samples × timestamps), that is, groups of genes that behave similarly across samples and timestamps.
However, even though biological experiments collect an increasing amount of data to be analyzed and correlated, the triclustering
problem remains a bottleneck due to its NP-Completeness, so its parallelization seems to be an essential step towards obtaining
feasible solutions. In this work we propose and evaluate the implementation of a parallel version of the Tricluster algorithm
using the filter-labeled-stream paradigm supported by the Anthill parallel programming environment. The results show that
our parallelization scales well with the data size, being able to handle severe load imbalances that are inherent to the problem.
Further more, the parallelization strategy is applicable to any depth-first searches. 相似文献
77.
Pierluigi Debernardi Renato Orta 《Quantum Electronics, IEEE Journal of》2007,43(3):269-274
Bragg mirrors, the key element of vertical-cavity surface-emitting lasers, always present graded interfaces when current is pumped through them, so as to reduce their series resistance and related heating problems. We present here an analytical solution for the electromagnetic fields in graded Bragg mirrors. It allows to generate reference reflection and transmission coefficients that are compared with those obtained by the staircase approximation method. Graded mirrors are then analyzed in detail and it is shown that, with an optimized design, higher reflectivity than in the abrupt scheme can be achieved 相似文献
78.
Renato Alexandre C. Santana Ana Regina N. Campos Emanuelle A. Medeiros Aldrighi Luiz M. Oliveira Liana Maria F. Silva Shiva Prasad 《Journal of Materials Science》2007,42(22):9137-9144
A ternary alloy Ni–W–Co was electrodeposited and operational parameters in relation to its corrosion resistance and deposition
efficiency were optimized. A 22 full factorial design was successfully employed for experimental design analysis of the results. By means of response surface
analysis, the statistical model identified the following operating conditions for obtaining corrosion resistant alloy: 60 mA/cm2 current density, 70 °C temperature, 20 rpm cathode rotation and 8.0 pH. The alloy was deposited at 36% current efficiency,
with an average composition of 70% Ni, 8% Co, 22% W and traces of boron and with E
corr −0.508 V and R
p
4.56 × 104 Ohm. The deposit obtained under these conditions had an amorphous character and showed good adherence, high corrosion resistance
and presence of nodules on its surface. Electrochemical corrosion tests verified that the Ni–W–Co alloy had better corrosion
resistance than similarly electrodeposited Co–W amorphous alloy. 相似文献
79.
Juliano Toniolo Antonio S. Takimi Mônica J. Andrade Renato Bonadiman Carlos P. Bergmann 《Journal of Materials Science》2007,42(13):4785-4791
This article describes the solution combustion synthesis technique as applicable to iron oxide powder production using urea
as fuel and ferric nitrate as an oxidizer. It focuses on the thermodynamic modeling of the combustion reaction under different
fuel-to-oxidant ratios. X-ray diffraction showed magnetite (Fe3O4) and hematite (α-Fe2O3) phase formations for the as-synthesized powders. The smallest crystallite size was obtained by stoichiometric chemical reaction.
The magnetic properties of the samples are also carefully discussed as superparamagnetic behavior. 相似文献
80.
Yoram Pressburger Renato Perucchio 《International journal for numerical methods in engineering》1995,38(8):1399-1421
This paper introduces an automatic self-adaptive finite element system for 3-D stress analysis of homogeneous elastic solids described in a Solid Modelling System (SMS). This system reduces the role of the analyst into two basic tasks: defining the problem (i.e. geometry, material properties and boundary conditions) and specifying the desired accuracy in the analysis. The approach followed in this work is based on Recursive Spatial Decomposition (RSD) of solids defined in a SMS. The system includes procedures for meshing, analysis, error estimation, and adaptive remeshing and reanalysis. The various procedures share the same hierarchical data structure built on the RSD. 相似文献