全文获取类型
收费全文 | 5077篇 |
免费 | 804篇 |
国内免费 | 118篇 |
专业分类
电工技术 | 37篇 |
综合类 | 266篇 |
化学工业 | 3227篇 |
金属工艺 | 101篇 |
机械仪表 | 65篇 |
建筑科学 | 113篇 |
矿业工程 | 25篇 |
能源动力 | 48篇 |
轻工业 | 509篇 |
水利工程 | 11篇 |
石油天然气 | 12篇 |
武器工业 | 16篇 |
无线电 | 379篇 |
一般工业技术 | 1078篇 |
冶金工业 | 65篇 |
原子能技术 | 16篇 |
自动化技术 | 31篇 |
出版年
2024年 | 28篇 |
2023年 | 112篇 |
2022年 | 59篇 |
2021年 | 223篇 |
2020年 | 214篇 |
2019年 | 203篇 |
2018年 | 254篇 |
2017年 | 225篇 |
2016年 | 229篇 |
2015年 | 269篇 |
2014年 | 286篇 |
2013年 | 371篇 |
2012年 | 297篇 |
2011年 | 295篇 |
2010年 | 237篇 |
2009年 | 279篇 |
2008年 | 238篇 |
2007年 | 285篇 |
2006年 | 340篇 |
2005年 | 223篇 |
2004年 | 260篇 |
2003年 | 227篇 |
2002年 | 173篇 |
2001年 | 111篇 |
2000年 | 101篇 |
1999年 | 56篇 |
1998年 | 81篇 |
1997年 | 55篇 |
1996年 | 33篇 |
1995年 | 31篇 |
1994年 | 28篇 |
1993年 | 24篇 |
1992年 | 27篇 |
1991年 | 46篇 |
1990年 | 26篇 |
1989年 | 28篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有5999条查询结果,搜索用时 10 毫秒
91.
Soubhik De P.N. Shivangi Saswat Choudhury Abhinav Omprakash Fulmali Bankim Chandra Ray Rajesh Kumar Prusty 《应用聚合物科学杂志》2021,138(42):51231
Carbon fiber reinforced epoxy (CE) composite is ideal for a cryogenic fuel storage tank in space applications due to its unmatched specific strength and modulus. In this article, inter-laminar shear strength (ILSS) of carbon fiber/epoxy (CE) composite is shown to be considerably improved by engineering the interface with carboxyl functionalized multi-walled carbon nanotube (FCNT) using electrophoretic deposition technique. FCNT deposited fibers from different bath concentrations (0.3, 0.5, and 1.0 g/L) were used to fabricate the laminates, which were then tested at room (30°C) and in-situ liquid nitrogen (LN) (−196°C) temperature as well as conditioning for different time durations (0.25, 0.5, 1, 6, and 12 h) followed by immediate RT testing to study the applicability of these engineered materials at the cryogenic environment. A maximum increment in ILSS was noticed at bath concentration of 0.5 g/L, which was ~21% and ~ 17% higher than neat composite at 30°C and − 196°C, respectively. Short-term LN conditioning was found to be detrimental due to developed cryogenic shock, which was further found to be compensated by cryogenic interfacial clamping upon long-term exposure. 相似文献
92.
Mahmoud M. A. Nassar Khalid I. Alzebdeh Tasneem Pervez Nasr Al-Hinai Abdul Munam 《应用聚合物科学杂志》2021,138(43):51284
Owing to economic and environmental benefits, new generations of materials/commodities follow “from waste to wealth” strategy. Recently, there has been a huge upsurge in research on the development of eco-composites using recycled plastic polymers and agro-residues because the eco-composites satisfy the stringent environment regulations and are cost-effective. Herein, we present a detailed review on the potential use of several types of natural fillers as an efficient reinforcement for recycled plastic polymers. In particular, the characterization of different categories of eco-composites according to their morphological, physical, thermal, and mechanical properties is extensively reviewed and their results are analyzed, compared, and highlighted. Furthermore, a framework to produce functional eco-composites, which includes functionalization of ingredients, critical issues on microstructural parameters, processing, and fabrication methods, is outlined and supported with sufficient data from the literature. Finally, the review outlines the emerging challenges and future prospects of eco-composites to be addressed by interested researchers to bridge the gap between research and commercialization of such a class of material. Overall, the acquired knowledge will guide researchers, scientists, and manufacturers to plan, select, and develop various forms of eco-composites with enhanced properties and optimized production processes. 相似文献
93.
Jing Lv Longhai Guo Chunjie Xie Weitong Xu Jun Ye Xiaoyu Li Teng Qiu Xinlin Tuo 《应用聚合物科学杂志》2021,138(44):51316
Being a new kind of nanomaterials, aromatic polyamide nanofibers (ANF) have been much highlighted in recent studies. We here demonstrate an isopropyl alcohol (IPA) accelerated chemical cleavage on poly (p-phenylene terephthalamide) chopped fibers, which provides an efficient preparation method of ANF. The comprehensive study on the processes accelerated by different alcohols revealed that the preparation time of ANF in the mixed medium of dimethyl sulfoxide (DMSO)-alcohol (20:1 in volume) was shorten to 45 min and 75 min for methanol (ethanol) and isopropanol, respectively. However, the nanofibers prepared in DMSO-IPA exhibited the minimum in axial and radial dimensions, providing the finest and most uniform diameter of 16 nm. The corresponding ANF films through vacuum assisted filtration also showed the highest tensile strength of 150 MPa, in comparison with those of the ANF films prepared using other alcohols, which were about 110 MPa. Furthermore, ANF/silicon hybrid films were prepared by the ionic ring-opening reaction followed by the alkoxysilane condensation and nanoparticle fabrication. By changing the organo functional groups in the alkoxysilane, the surface of the films were adjustable in a wide contact angle range from 56° (hydrophilic) to 150° (superhydrophobic), suggesting the amendable interfacial properties potential applicable to composite fabrication with most of the resin matrix. 相似文献
94.
Bo Zhang Xiaoming Shao Tianze Liang Wencai Wang Ming Tian Nanying Ning Liqun Zhang 《应用聚合物科学杂志》2021,138(39):51011
In order to improve the interfacial adhesion between aramid fiber (AF) and rubber matrix, a simple and facile method of aramid nanofiber (ANF) coating is demonstrated in this article. Tannic acid (TA) and polyethyleneimine (PEI) are polymerized in an alkaline solution to form a thin TA/PEI (TP) layer that is deposited on the surface of AF to introduce functional groups such as hydroxyl and amino groups. Then, the ANF coating is utilized to construct nanostructures on the surface of AF to improve the interfacial adhesion between the fiber and the rubber. Through hydrogen bonding and/or π-π stacking between the TP layer and the ANF, the ANF coating is firmly attached to the surface of AF. Compared with the untreated fiber, the interfacial adhesion of AF coated with ANF after 1, 3, 5, 7, 9 deposition cycles is increased by 27.8%, 29.1%, 31.5%, 43.1%, and 30.3%, and the mechanical properties of the fibers remain almost unchanged. This method shows its advantages of simple, facile, and time-effective, which is of great significance for industrial applications. 相似文献
95.
Cr (VI) is a highly toxic pollutant to humans, to achieve high adsorption capacity, easy recovery, and good reusability, polyethersulfone/polydopamine (PES/PDA) ultrafine fibers were prepared successfully. A series of preparing effect factors were investigated systematically and the optimum one is 8.5 pH value at room temperature and 2 g/L dopamine concentration. And then they were used as an adsorbent for the removal of Cr (VI) ions from wastewater. The effect factors pH, the adsorbent dosage, and time were discussed on Cr (VI) adsorption process and the Cr (VI) adsorption behavior was investigated. It is found that the maximum Cr (VI) adsorption capacity is 115.2 ± 4.8 mg/g at pH = 3 using 0.06 g PES/PDA with 80 mins. The Cr (VI) adsorption process followed the pseudo-second-order model (r2 ≥ 0.99) and adsorption isotherms were fitted to the Langmuir model (R2 ≥ 0.999). Furthermore, the Cr (VI) adsorption mechanism was supposed according to the X-ray photoelectron spectroscopic results. Finally, PES/PDA ultrafine fibers were considered to be a promising adsorbent with good stability (decomposing temperature, 356°C), high adsorption efficiency (112.1 ± 2.5 mg/g), and good reusability (three times) on the coexistence of anions and the actual industry wastewater environment. 相似文献
96.
A simple and feasible method to enhance the wear resistance of ultra-high molecular weight polyethylene (UHMWPE) fibers was reported. The graphite oxide (GO) prepared using improved Hummer's method was surface modified with hexadecylamine to improve its compatibility with UHMWPE. Combined with well-dispersion of modified-GO (m-GO) in dichloromethane and the fact that the viscosity of UHMWPE suspension can be decreased by dichloromethane, the well dispersed m-GO/dichloromethane was added into UHMWPE suspension to improve m-GO dispersion in UHMWPE fibers. Finally, UHMWPE fibers with different m-GO concentration were prepared using gel spinning technology. The effect of m-GO concentration on the structure and properties of modified UHMWPE fibers were investigated. The results indicated that the melting temperature and crystallinity of m-GO modified UHMWPE fibers increased with increasing of m-GO concentration, while the fiber's crystal sizes and orientation increased, thus the tensile strength of m-GO modified UHMWPE fibers remained almost undamaged. The introduction of m-GO is beneficial to the formation of smooth transfer film on fiber's surface, which enhanced the self-lubrication of UHMWPE fibers. Compared with pure UHMWPE fiber, the UHMWPE fiber containing 1.5 wt% m-GO had enhanced wear resistance by 55.4% and still maintained high tensile strength of 29.98 cN dtex−1. 相似文献
97.
Mesophase pitch was separated into different pitch fractions to investigate the effect of pitch fractions on the properties of their nanofibers prepared by electrospinning. The evolution of different pitch fractions-derived nanofibers during stabilization and carbonization were explored, and the properties of the resultant carbon nanofibers (CNFs) as electrode materials for supercapacitor were compared. Results indicated that the hexane insoluble-toluene soluble (HI-TS) and toluene insoluble-tetrahydrofuran (THF) soluble (TI-THFS) fractions had good spinnability due to their narrow molecular weight distribution. Moreover, compared with HI-TS and THF insoluble (THFI), TI-THFS consisted of appropriate aromaticity and branched alkyl groups which promoted the stabilization and carbonization behaviors of its nanofibers, resulting in maintaining ideal fiber morphology of TI-THFS-derived nanofiber due to the mitigation of their exothermic reactions. Meanwhile, the TI-THFS-derived CNFs presented the highest surface area of 543 m2 g−1 and exhibited an excellent specific capacitance of 167 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte. 相似文献
98.
99.
Unidirectionally reinforced graphite/copper composites have been fabricated using a pressure infiltration casting procedure.
T300 and T650 graphite fibers have been used to reinforce copper and copperchromium alloys. The effects of the chromium level
in the copper matrix on the tensile strength, stiffness, and thermal expansion behavior of the composites have been evaluated
through tensile and three-point bend testing, and thermal cycling. At the 0.5 wt% alloying level, chromium increases the stiffness
and optimizes the thermal expansion behavior of graphite/copper composites. The longitudinal tensile strengths of these composites
are above 1606 MPa, whereas the transverse tensile strengths are lower than 40 MPa due to incomplete infiltration during processing.
Scanning electron microscopy analyses reveal that the unalloyed copper matrix composites experienced extensive fiber/matrix
debonding under tensile loading. The addition of chromium to the copper increases the level of matrix bonding to the graphite
fibers, as evidenced by observations of fractured tensile specimens. Auger electron spectroscopy analyses indicate that a
chromium carbide phase present at the interface is responsible for the improved bonding. 相似文献
100.