全文获取类型
收费全文 | 256篇 |
免费 | 17篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 55篇 |
金属工艺 | 3篇 |
机械仪表 | 10篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 15篇 |
轻工业 | 39篇 |
水利工程 | 1篇 |
石油天然气 | 6篇 |
无线电 | 33篇 |
一般工业技术 | 59篇 |
冶金工业 | 7篇 |
原子能技术 | 1篇 |
自动化技术 | 32篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 18篇 |
2021年 | 16篇 |
2020年 | 16篇 |
2019年 | 20篇 |
2018年 | 15篇 |
2017年 | 16篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 23篇 |
2012年 | 10篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 13篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1980年 | 2篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有273条查询结果,搜索用时 31 毫秒
91.
92.
J. F. Branthaver Muhammed Nazir J. C. Petersen S. M. Dorrence 《Petroleum Science and Technology》2013,31(4):355-369
ABSTRACT Two different asphalts were coated on a Fluoropak support and were oxidized at 130 ± 2°C for 24 hours using a number of metal chelales as additives. After oxidation the recovered asphalts were analyzed by infrared spectrometry to determine enhancements of keto, acid, and anhydride functions. Vanadyl etioporphyrin I was found to be an effective promoter in the oxidation of both asphalts. Vanadyl porphyrins having bulky ring substituents are not as effective as vanadyl etioporphyrin I in promoting asphalt oxidations. 相似文献
93.
Luis E. Simental-Mendía Matteo Pirro Antonio M. Gotto Jr. Maciej Banach Stephen L. Atkin Muhammed Majeed 《Critical reviews in food science and nutrition》2019,59(7):1178-1187
Objective: The aim of this systematic review and meta-analysis was to determine and clarify the impact of curcuminoids on serum lipid levels. Methods: Randomized controlled trials (RCTs) investigating the effects of curcuminoids on plasma lipids were searched in PubMed-Medline, Scopus, Web of Science databases (from inception to April 3rd, 2017). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipid concentrations. Results: A meta-analysis of 20 RCTs with 1427 participants suggested a significant decrease in plasma concentrations of triglycerides (WMD: ?21.36 mg/dL, 95% CI: ?32.18, ?10.53, p < 0.001), and an elevation in plasma HDL-C levels (WMD: 1.42 mg/dL, 95% CI: 0.03, 2.81, p = 0.046), while plasma levels of LDL-C (WMD: ?5.82 mg/dL, 95% CI: ?15.80, 4.16, p = 0.253) and total cholesterol (WMD: ?9.57 mg/dL, 95% CI: ?20.89, 1.75, p = 0.098) were not altered. The effects of curcuminoids on lipids were not found to be dependent on the duration of supplementation. Conclusion: This meta-analysis has shown that curcuminoid therapy significantly reduces plasma triglycerides and increases HDL-C levels. 相似文献
94.
研究了基于高光谱成像技术快速检测药用胶囊铬含量的方法。首先应用传统的原子吸收分光法对药用明胶空心硬胶囊分析结果作为对照组,再对1048个胶囊(含正常和含有重金属铬)样本的高光谱数据进行降维和定性分析,最后选择偏最小二乘判别分析方法对光谱数据进行处理。当用4个偏最小二乘算子(LV)作为偏最小二乘法模型中的输入特征,分类准确率可达100%,2种样本的交叉验证和样本预测相关系数分别为0.923和0.972;敏感度与特异度均为100%。 相似文献
95.
P. Muhammed Thanseer Avijit Kr. Metya S. Palit Sagar 《Journal of Materials Engineering and Performance》2017,26(6):2632-2639
Non-collinear nonlinear ultrasonic (NCNLU) wave mixing technique has been established to study the localized plastic deformation at the crack tip during fatigue. A pair of ultrasonic shear wave was mixed non-collinearly to obtain a longitudinal wave of frequency equal to the sum of the two shear wave frequencies under a resonant condition. Experiments were carried out on notched 9Cr-1Mo 3-point bend specimen during high-cycle fatigue. The variation of the NCNLU parameter with the stress accumulation at the crack tip during the fatigue crack initiation and propagation and mapping of the deformation zone around the crack tip are described in this paper. 相似文献
96.
M. Azhar Khan M.U. Islam M. Ishaque I.Z. Rahman A. Genson S. Hampshire 《Materials Characterization》2009,60(1):73-78
A series of soft ferrites in the system Ni1 ? xTbxFe2O4 (0 ≤ x ≤ 0.2), was prepared by a standard ceramic technique. The influence of terbium content was investigated by means of X-ray diffraction, Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy. The X-ray diffraction analysis reveals that the samples have a cubic spinel (single phase) structure for 0 ≤ x ≤ 0.08; for x > 0.08 a small peak of orthorhombic phase (TbFeO3) appears and becomes more conspicuous with increased terbium substitution. The lattice parameter changes in a non-linear way as a function of terbium content which may be attributed to differences in the ionic radii of the cations involved and the solubility limit of terbium ions. A gradual increase in the bulk density was observed with the increase of terbium concentration, from 5.13 g/cm3 to 5.69 g/cm3. FTIR absorption spectra of the Ni–Tb–Fe–O system were investigated in the wave number range 370–1500 cm? 1. Each spectrum exhibited two main absorption bands, thereby confirming the spinel structure. 相似文献
97.
Edakkattuparambil Sidharth Shibu Madathumpady Abubaker Habeeb Muhammed Keisaku Kimura Thalappil Pradeep 《Nano Research》2009,2(3):220-234
Fluorescent three-dimensional (3-D) superlattices of dansyl glutathione protected gold nanoparticles, with potential applications
in molecular detection, have been synthesized at an air/water interface by controlling the pH of the nanoparticle suspension.
The number of fluorophores per nanoparticle was calculated to be ∼127. Morphologies of the superlattice crystals were examined
using scanning electron microscopy (SEM). Most of the crystals observed were triangular in shape. High-resolution transmission
electron microscopy (HRTEM) and small angle X-ray scattering (SAXS) were used to study the packing of nanoparticles in these
crystals. Both these studies showed that the nanoparticles were arranged in a face-centered cubic (fcc) pattern with a particle-particle
distance (center-center) of ∼10.5 nm. Evolution of the crystal morphologies with time was also examined. The fluorescence
properties of these triangles were studied using confocal fluorescence imaging and confocal Raman mapping, which were in good
agreement with the morphologies observed by SEM. The superlattice exhibits near-infrared (NIR) absorption in the range 1100–2500
nm. Easy synthesis of such functional nanoparticle-based solids makes it possible to use them in novel applications. We utilized
the fluorescence of dansyl glutathione gold superlattice crystals for the selective detection of bovine serum albumin (BSA),
the major protein constituent of blood plasma, based on the selective binding of the naphthalene ring of the dansyl moiety
with site I of BSA.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
This article is published with open access at Springerlink.com 相似文献
98.
Piping is one of the most important issues in the cost of process factories. It is known that 80% of bought equipment cost or 20% of overhead capital can belong to piping cost in a fluid-process factory. Pipe diameter and therefore flow velocity strongly affect the existing value of the factory regarding the consumed electric energy and fitting cost of pipes, pumps, and valves. We give a detailed cost analysis model for the pure fluids of water, motor oil, glycerin, ammonia, methanol, ethanol, ethylene glycol, and propane and their nanofluid mixtures with Ti and TiO2 particles in liquid phase flowing in the tube side of a double-pipe heat exchanger. Pressure drop and pumping power values increase with flow velocity but total cost values show an arc with it. The clear outcome is that there is a minimum cost value as a result of the analyses for each investigated fluids. Moreover, validation of the model is performed by plotting the calculated items in figures such as total heat transfer coefficient versus Reynolds number, pressure drop versus Reynolds number, and friction factor versus mass flow rate. Characteristics of the trend lines in these figures are seen as they should be. 相似文献
99.
C. Muhammed Ajmal Seonghyun Bae Seunghyun Baik 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(1)
Nanocomposite fibers, composed of conductive nanoparticles and polymer matrix, are crucial for wearable electronics. However, the nanoparticle mixing approach results in aggregation and dispersion problems. A revolutionary synthesis method by premixing silver precursor ions (silver ammonium acetate) with polyvinyl alcohol is reported here. The solvation of ions‐prevented aggregation, and uniformly distributed silver nanoparticles (in situ AgNPs, 77 nm) are formed after thermal reduction (155 °C) without using additional reducing or dispersion agents. The conductive fiber is synthesized by the wet spinning technology. After careful optimization, flower‐shaped silver nanoparticles (AgNFs, 350–450 nm) are also employed as cofillers. The addition of in situ AgNPs (9.5 vol%) to AgNFs (30 vol%) increases electrical conductivity by 1434% (2090 to 32 064 S cm?1) through the efficient construction of percolation networks. The in situ AgNPs provide significantly higher conductivity compared with other secondary nanoparticle fillers. The gaseous byproducts dramatically increase flexibility with a moderate compromise in tensile strength (55 MPa). The particle‐free ion‐level uniform mixing of silver precursors, followed by in situ reduction, would be a fundamental paradigm shift in nanocomposite synthesis. 相似文献
100.
Muhammed Iraqi Priyanka Bolel Rhitajit Sarkar Baisali Bhattacharya Muhammad Abu Ahmad Avishay Edri Laila C. Roisman Moshe Elkabets Walid Shalata Nir Peled Angel Porgador 《International journal of molecular sciences》2022,23(22)
Lung cancer cells in the tumor microenvironment facilitate immune evasion that leads to failure of conventional chemotherapies, despite provisionally decided on the genetic diagnosis of patients in a clinical setup. The current study follows three lung cancer patients who underwent “personalized” chemotherapeutic intervention. Patient-derived xenografts (PDXs) were subjected to tumor microarray and treatment screening with chemotherapies, either individually or in combination with the peptide R11-NLS-pep8; this peptide targets both membrane-associated and nuclear PCNA. Ex vivo, employing PDX-derived explants, it was found that combination with R11-NLS-pep8 stimulated antineoplastic effect of chemotherapies that were, although predicted based on the patient’s genetic mutation, inactive on their own. Furthermore, treatment in vivo of PDX-bearing mice showed an exactly similar trend in the result, corroborating the finding to be translated into clinical setup. 相似文献