全文获取类型
收费全文 | 3948篇 |
免费 | 210篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 25篇 |
综合类 | 2篇 |
化学工业 | 781篇 |
金属工艺 | 57篇 |
机械仪表 | 72篇 |
建筑科学 | 155篇 |
矿业工程 | 12篇 |
能源动力 | 57篇 |
轻工业 | 736篇 |
水利工程 | 87篇 |
石油天然气 | 15篇 |
无线电 | 165篇 |
一般工业技术 | 590篇 |
冶金工业 | 881篇 |
原子能技术 | 18篇 |
自动化技术 | 507篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 69篇 |
2021年 | 112篇 |
2020年 | 77篇 |
2019年 | 70篇 |
2018年 | 120篇 |
2017年 | 138篇 |
2016年 | 142篇 |
2015年 | 122篇 |
2014年 | 143篇 |
2013年 | 299篇 |
2012年 | 254篇 |
2011年 | 239篇 |
2010年 | 185篇 |
2009年 | 165篇 |
2008年 | 179篇 |
2007年 | 186篇 |
2006年 | 115篇 |
2005年 | 100篇 |
2004年 | 97篇 |
2003年 | 77篇 |
2002年 | 79篇 |
2001年 | 53篇 |
2000年 | 41篇 |
1999年 | 46篇 |
1998年 | 302篇 |
1997年 | 181篇 |
1996年 | 132篇 |
1995年 | 81篇 |
1994年 | 57篇 |
1993年 | 55篇 |
1992年 | 28篇 |
1991年 | 24篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 13篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1977年 | 11篇 |
1976年 | 24篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有4160条查询结果,搜索用时 15 毫秒
21.
M. Fernández-Delgado M. Reboreda E. Cernadas S. Barro 《Neural computing & applications》2010,19(5):741-754
In the industrial environment, specifically in the automotive industry, an accurate prediction of execution times for each
production task is very useful in order to plan the work and to optimize the human, technical and material resources. In this
paper, we applied several regression neural networks to predict the execution times of the tasks in the production of parts
for plastic injection molds. These molds are used to make a variety of car components in automotive industry. The prediction
is based on the geometric features of the mold parts to be made. The accuracy of the predicted times is high enough to be
used as a tool for the design stage of the mold parts, e.g. guiding the design process in order to get the lowest production
time. 相似文献
22.
23.
In this paper we present the "R&W Simulator" (version 3.0), a Java simulator of Rescorla and Wagner's prediction error model of learning. It is able to run whole experimental designs, and compute and display the associative values of elemental and compound stimuli simultaneously, as well as use extra configural cues in generating compound values; it also permits change of the US parameters across phases. The simulator produces both numerical and graphical outputs, and includes a functionality to export the results to a data processor spreadsheet. It is user-friendly, and built with a graphical interface designed to allow neuroscience researchers to input the data in their own "language". It is a cross-platform simulator, so it does not require any special equipment, operative system or support program, and does not need installation. The "R&W Simulator" (version 3.0) is available free. 相似文献
24.
A Nadal P Jares M Cazorla PL Fernández X Sanjuan L Hernandez M Pinyol M Aldea C Mallofré J Muntané J Traserra E Campo A Cardesa 《Canadian Metallurgical Quarterly》1997,183(2):156-163
The anti-metastatic effect of Z-100, an immunomodulatory arabinomannan extracted from Mycobacterium tuberculosis, was investigated in mice bearing B16 melanoma cells. Treatment of BF10 mice implanted with high metastatic B16F10 melanoma cells with a 10 mg/kg dose of Z-100 resulted in the reduction of experimental pulmonary metastasis as compared with that of BF10 mice treated with saline. The number of pulmonary metastatic colonies in BF1 mice (mice implanted with low metastatic B16F1 melanoma cells) was greatly increased after the inoculation of CD4+ CD11b+ CD281+ TCR alphabeta+ type 2 T cells (F10-Th2 cells) derived from BF10 mice, while only a few metastatic colonies were demonstrated in lungs of BF1 mice inoculated with naive CD4+ T cells. However, the numbers of metastatic colonies in BF1 mice were not increased when they were inoculated with the F10-Th2 cell fraction derived from Z-100-treated BF10 mice and the generation of F10-Th2 cells in BF10 mice was effectively suppressed by the Z-100 treatment. These results suggest that Z-100 inhibits pulmonary metastasis of B16 melanoma through the regulation of tumor-associated Th2 cells, which are a key cell in the acceleration of tumor metastasis. 相似文献
25.
Elisabetta Tabolacci Veronica Nobile Cecilia Pucci Pietro Chiurazzi 《International journal of molecular sciences》2022,23(10)
A dynamic mutation in exon 1 of the FMR1 gene causes Fragile X-related Disorders (FXDs), due to the expansion of an unstable CGG repeat sequence. Based on the CGG sequence size, two types of FMR1 alleles are possible: “premutation” (PM, with 56-200 CGGs) and “full mutation” (FM, with >200 triplets). Premutated females are at risk of transmitting a FM allele that, when methylated, epigenetically silences FMR1 and causes Fragile X syndrome (FXS), a very common form of inherited intellectual disability (ID). Expansions events of the CGG sequence are predominant over contractions and are responsible for meiotic and mitotic instability. The CGG repeat usually includes one or more AGG interspersed triplets that influence allele stability and the risk of transmitting FM to children through maternal meiosis. A unique mechanism responsible for repeat instability has not been identified, but several processes are under investigations using cellular and animal models. The formation of unusual secondary DNA structures at the expanded repeats are likely to occur and contribute to the CGG expansion. This review will focus on the current knowledge about CGG repeat instability addressing the CGG sequence expands. 相似文献
26.
Karina Gonzlez-García Armando Lpez-Martínez Juan Manuel Velzquez-Enríquez Cecilia Zertuche-Martínez Gabriela Carrasco-Torres Luis Manuel Snchez-Navarro Saúl Villa-Trevio Rafael Baltirrez-Hoyos Vernica Rocío Vsquez-Garzn 《International journal of molecular sciences》2022,23(14)
Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by parenchymal scarring, leading progressively to alveolar architecture distortion, respiratory failure, and eventually death. Currently, there is no effective treatment for IPF. Previously, 3′5-dimaleamylbenzoic acid (3′5-DMBA), a maleimide, demonstrated pro-apoptotic, anti-inflammatory, and anti-cancer properties; however, its potential therapeutic effects on IPF have not been addressed. Bleomycin (BLM) 100 U/kg was administered to CD1 mice through an osmotic minipump. After fourteen days of BLM administration, 3′5-DMBA (6 mg/kg or 10 mg/kg) and its vehicle carboxymethylcellulose (CMC) were administered intragastrically every two days until day 26. On day 28, all mice were euthanized. The 3′5-DMBA effect was assessed by histological and immunohistochemical staining, as well as by RT-qPCR. The redox status on lung tissue was evaluated by determining the glutathione content and the GSH/GSSG ratio. 3′5-DMBA treatment re-established typical lung histological features and decreased the expression of BLM-induced fibrotic markers: collagen, α-SMA, and TGF-β1. Furthermore, 3′5-DMBA significantly reduced the expression of genes involved in fibrogenesis. In addition, it decreased reduced glutathione and increased oxidized glutathione content without promoting oxidative damage to lipids, as evidenced by the decrease in the lipid peroxidation marker 4-HNE. Therefore, 3′5-DMBA may be a promising candidate for IPF treatment. 相似文献
27.
Marcos J. López Fernández Jorge Guzón Fernández Sergio Ríos Aguilar Blanca Salazar Selvi Rubén González Crespo 《Expert systems with applications》2013,40(11):4478-4489
This paper presents an improved attendance control system, required for continuous evaluation which has become compulsory following the Bologna Process. It provides a solution based on NFC technology and is based on a real project developed and pilot tested at the “Universidad Pontificia de Salamanca, Campus Madrid”. 相似文献
28.
J. Fernández‐Berni R. Carmona‐Galán 《International Journal of Circuit Theory and Applications》2012,40(8):859-876
This paper addresses the design and VLSI implementation of MOS‐based RC networks capable of performing time‐controlled Gaussian filtering. In these networks, all the resistors are substituted one by one by a single MOS transistor biased in the ohmic region. The design of this elementary transistor is carefully realized according to the value of the ideal resistor to be emulated. For a prescribed signal range, the MOSFET in triode region delivers an interval of instantaneous resistance values. We demonstrate that, for the elementary 2‐node network, establishing the design equation at a particular point within this interval guarantees minimum error. This equation is then corroborated for networks of arbitrary size by analyzing them from a stochastic point of view. Following the design methodology proposed, the error committed by an MOS‐based grid when compared with its equivalent ideal RC network is, despite the intrinsic nonlinearities of the transistors, below 1% even under mismatch conditions of 10%. In terms of image processing, this error hardly affects the outcome, which is perceptually equivalent to that of the ideal network. These results, extracted from simulation, are verified in a prototype vision chip with QCIF resolution manufactured in the AMS 0.35µm CMOS‐OPTO process. This prototype incorporates a focal‐plane MOS‐based RC network that performs fully programmable Gaussian filtering. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
29.
Artifact removal in magnetoencephalogram background activity with independent component analysis 总被引:2,自引:0,他引:2
Escudero J Hornero R Abásolo D Fernández A López-Coronado M 《IEEE transactions on bio-medical engineering》2007,54(11):1965-1973
The aim of this study was to assess whether independent component analysis (ICA) could be valuable to remove power line noise, cardiac, and ocular artifacts from magnetoencephalogram (MEG) background activity. The MEGs were recorded from 11 subjects with a 148-channel whole-head magnetometer. We used a statistical criterion to estimate the number of independent components. Then, a robust ICA algorithm decomposed the MEG epochs and several methods were applied to detect those artifacts. The whole process had been previously tested on synthetic data. We found that the line noise components could be easily detected by their frequency spectrum. In addition, the ocular artifacts could be identified by their frequency characteristics and scalp topography. Moreover, the cardiac artifact was better recognized by its skewness value than by its kurtosis one. Finally, the MEG signals were compared before and after artifact rejection to evaluate our method. 相似文献
30.
J. F. Fernández‐Sánchez I. Fernández R. Steiger R. Beer R. Cannas U. E. Spichiger‐Keller 《Advanced functional materials》2007,17(7):1188-1198
An iron(II) phthalocyanine (FePc) complex solubilized by decylamine (DA) and benzylamine (BA) is incorporated into a nanoparticulate metal oxide matrix to develop optical sensor films sensitive to NO2 and CO. Eleven amine solvents have been tested as N‐donor ligands that permit ligand exchange with the gas molecules. We have systematically investigated the suitability of different N‐donor ligands, studied the thermal stability of the NO2‐ and CO‐sensing films at 4, 25, 60, and 80 °C by photometry, and corroborated our findings by using NMR experiments. A satisfactory thermal stability of the films has not been obtained for chemically unmodified nanoparticulate metal oxide matrices. We have therefore developed a second generation of nanostructured metal oxide supports that show increased thermal stability and adequate sensitivity to NO2 and CO. These novel nanostructured matrices have been chemically modified using amines, alumina oligomers, and/or anti‐gas‐fading agents. These components have been integrated into the metal oxide matrices to avoid degradation of the optical films and to preserve their sensitivity. 相似文献