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101.
Ma T Shrestha PL Hempel M Peng D Sharif H Chen HH 《IEEE transactions on bio-medical engineering》2012,59(4):1041-1048
With the technological advancement in body area sensor networks (BASNs), low cost high quality electrocardiographic (ECG) diagnosis systems have become important equipment for healthcare service providers. However, energy consumption and data security with ECG systems in BASNs are still two major challenges to tackle. In this study, we investigate the properties of compressed ECG data for energy saving as an effort to devise a selective encryption mechanism and a two-rate unequal error protection (UEP) scheme. The proposed selective encryption mechanism provides a simple and yet effective security solution for an ECG sensor-based communication platform, where only one percent of data is encrypted without compromising ECG data security. This part of the encrypted data is essential to ECG data quality due to its unequally important contribution to distortion reduction. The two-rate UEP scheme achieves a significant additional energy saving due to its unequal investment of communication energy to the outcomes of the selective encryption, and thus, it maintains a high ECG data transmission quality. Our results show the improvements in communication energy saving of about 40%, and demonstrate a higher transmission quality and security measured in terms of wavelet-based weighted percent root-mean-squared difference. 相似文献
102.
103.
Alireza Sharif Jamal Aalaie Homeira Shariatpanahi Homayoon Hosseinkhanli Alireza Khoshniyat 《Journal of Polymer Research》2011,18(6):1955-1969
The effects of nanoclay on the structure and final properties of high density polyethylene (HDPE)/thermoplastic starch (TPS)
blends were investigated. Neat blends as well as nanoclay containing samples were prepared by melt blending in an internal
mixer. Also, a poly (ethylene-g-maleic anhydride) (PE-g-MA) copolymer was used as compatibilizer in some of the formulations.
Nanocomposites with intercalated structures were obtained in the samples lacking the compatibilizer, based on the rheological,
X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. However, some of the silicate layers were nearly
exfoliated in the presence of the compatibilizer. The nanoclay was located preferably in the HDPE matrix as well as at the
interface of the HDPE matrix and TPS dispersed phase. The ability of the nanoclays in decreasing the average size of TPS phase
in the HDPE matrix was confirmed by scanning electron microscopy (SEM) observations. Furthermore, thermo-gravimetric analysis
(TGA) showed that the nanoclays could enhance the thermal stability of the samples. It seems that nanoclays performed as an
insulator and mass transport barrier to the small molecules generated during decomposition, and assisted in the formation
of char after thermal decomposition of the polymer matrix. All the samples containing the compatibilizer possessed higher
tensile strength and elongation at break, but lower modulus, compared to the corresponding un-compatibilized samples. Finally,
incorporation of the nanoclays was found to be in favor of developing nanocomposites with higher biodegradability as evidenced
through a biodegradation test by fungi as well as water uptake experiments. 相似文献
104.
Fahmina Zafar Hina Zafar Eram Sharmin S. M. Ashraf Sharif Ahmad 《Journal of Inorganic and Organometallic Polymers and Materials》2011,21(3):646-654
In this paper linseed oil based metallopolyesteramides (Mn(II)-/Co(II)-/Cu(II)-LPEA) containing metals [with half filled (d
5) and partially filled (d
7 and d
9) d orbitals] were synthesized via green route for the application of eco-friendly protective green material. This paper also
described the role of occupancy of d orbitals on the performance of such polymers. The synthesis reaction was carried out in situ through condensation polymerization
among linseed fatty amide diol (HELA), phthalic anhydride and respective metal acetates [M (OCOCH3)2; M = Mn(II), Co(II), Cu(II); different mole ratios] in absence of any harmful organic solvent. The structural determination
(FTIR, 1H-NMR and 13C-NMR), curing, thermal, physico-chemical, physico-mechanical, anticorrosive/chemical resistance, antibacterial properties
of Mn(II)-/Co(II)-/Cu(II)-LPEA were carried out. The curing mechanism of the resin was confirmed by the comparison of FTIR
spectra of uncured and cured resin. The curing mechanism of Mn(II)-/Co(II)-/Cu(II)-LPEA is found to be contrary to that of
reported oil based polymer that involves the lipid autoxidation (slow process) in which driers are required to speed up the
room temperature curing process. The incorporation of metals in Mn(II)-/Co(II)-/Cu(II)-LPEA improved the thermal stability
as compared to virgin linseed oil based polyesteramide (LPEA). Mn(II)-/Co(II)-/Cu(II)-LPEA also show excellent antibacterial
performance against Staphylococcus aureus and Escherichia coli. The observed diversity in material properties suggests that Mn-LPEA may be useful as an eco-friendly protective green material
with thermal stability up to 320–330 °C. 相似文献
105.
Mohammad Kashif Eram Sharmin Fahmina Zafar Sharif Ahmad 《Journal of the American Oil Chemists' Society》2011,88(12):1989-1996
Ricinus communis (RC) oil-based materials are currently receiving increasing attention because of economic and environmental concerns. In
the present work, RC oil—a natural triol has been utilized for the development of an advanced polymeric material—poly(urethane-ricinoleamide)
(PUR) through very simple synthesis and curing strategy, omitting derivatization steps or side reactions, chain extenders
and crosslinkers. The synthesis of PUR was carried out in two steps. The first step is the introduction of an amide group
in the RC oil (89.5% ricinoleic acid) via base catalyzed amidation, which results in N, N-bis (2-hydroxyethyl) ricinoleamide (HERA). The second step is urethanation of HERA by the reaction of toluene-2,4-diisocyanate
(TDI) in minimal possible organic solvent by one-shot technique, which results in the formation of polyurethane along with
amide linkages. The physico-chemical and spectral studies (FT-IR, 1H-NMR and 13C-NMR techniques) confirm these two reactions and the structure of PUR. The resin was cured at ambient temperature without
any cross linker. Solubility of the resin was investigated in different polar and non-polar solvents. Thermo-gravimetric analysis
(TGA)/differential thermal analysis (DTA) and Differential Scanning Calorimetry (DSC) were used to determine the thermal stability
and curing behavior of PUR. An ambient cured ricinoleamide modified polyurethane resin exhibited thermal resistance up to
200–220 °C. 相似文献
106.
Homayoon Hosseinkhanli Alireza Sharif Jamal Aalaie Talat Khalkhali Shahin Akhlaghi 《乙烯基与添加剂工艺杂志》2013,19(2):132-139
Various (low‐density polyethylene)/poly(ethylene‐co‐vinyl acetate) (LDPE/EVA) nanocomposites containing organoclay were prepared by one‐ and two‐step procedures through melt blending. The resultant nanocomposites were then processed via the film blowing method. From the morphological point of view, X‐ray diffraction and optical microscopy studies revealed that although a prevalent intercalated morphology was evident in the absence of EVA, a remarkable increase of organoclay interlayer spacing occurred in the EVA‐containing systems. The advantages of the addition of EVA to the LDPE/organoclay nanocomposites were confirmed in terms of oxygen barrier properties. In other words, the oxygen transmission rates of the LDPE/EVA/organoclay systems were significantly lower than that of the LDPE/organoclay sample. The LDPE/EVA/organoclay films had better mechanical properties than their counterparts lacking the EVA, a result which could be attributed to the improvement of the organoclay reinforcement efficiency in the presence of EVA. Differential scanning calorimetry and thermogravimetric analysis experiments were performed to follow the effects of the EVA and/or organoclay on the thermal properties of LDPE. Finally, the films produced from the two‐step‐procedure compound showed enhanced oxygen barrier properties and mechanical behavior as compared to the properties of the films produced via the one‐step procedure. J. VINYL ADDIT. TECHNOL., 19:132–139, 2013. © 2013 Society of Plastics Engineers 相似文献
107.
Zaitunnatakhin Zamli Michael A. Adams John F. Tarlton Mohammed Sharif 《International journal of molecular sciences》2013,14(9):17729-17743
Osteoarthritis (OA) is the most common joint disease characterised by degradation of articular cartilage and bone remodelling. For almost a decade chondrocyte apoptosis has been investigated as a possible mechanism of cartilage damage in OA, but its precise role in initiation and/or progression of OA remains to the determined. The aim of this study is to determine the role of chondrocyte apoptosis in spontaneous animal models of OA. Right tibias from six male Dunkin Hartley (DH) and Bristol Strain 2 (BS2) guinea pigs were collected at 10, 16, 24 and 30 weeks of age. Fresh-frozen sections of tibial epiphysis were microscopically scored for OA, and immunostained with caspase-3 and TUNEL for apoptotic chondrocytes. The DH strain had more pronounced cartilage damage than BS2, especially at 30 weeks. At this time point, the apoptotic chondrocytes were largely confined to the deep zone of articular cartilage (AC) with a greater percentage in the medial side of DH than BS2 (DH: 5.7%, 95% CI: 4.2–7.2), BS2: 4.8%, 95% CI: 3.8–5.8), p > 0.05). DH had a significant progression of chondrocyte death between 24 to 30 weeks during which time significant changes were observed in AC fibrillation, proteoglycan depletion and overall microscopic OA score. A strong correlation (p ≤ 0.01) was found between chondrocyte apoptosis and AC fibrillation (r = 0.3), cellularity (r = 0.4) and overall microscopic OA scores (r = 0.4). Overall, the rate of progression in OA and apoptosis over the study period was greater in the DH (versus BS2) and the medial AC (versus lateral). Chondrocyte apoptosis was higher at the later stage of OA development when the cartilage matrix was hypocellular and highly fibrillated, suggesting that chondrocyte apoptosis is a late event in OA. 相似文献
108.
M.H.A. Jahurul I.S.M. Zaidul N.A.N. Norulaini F. Sahena S. Jinap J. Azmir K.M. Sharif A.K. Mohd Omar 《Journal of food engineering》2013
The current concern for cocoa butter fat as major ingredients of chocolate intake in the World has raised the question of the high price of cocoa butter among all other vegetable fats. Productions of natural cocoa butter fats are decreasing day by day due to the decrease of cocoa cultivation worldwide; moreover, cocoa fruit contains only a little amount of cocoa butter. Therefore, the food industries are keen to find the alternatives to cocoa butter fat and this issue has been contemplated among food manufacturers. This review offers an update of scientific research conducted in relation to the alternative fats of cocoa butter from natural sources. The findings highlights how these cocoa butter alternatives are being produced either by blending, modifying the natural oils or fats from palm oil, palm kernel oil, mango seed kernel fats, kokum butter fat, sal fat, shea butter, and illipé fat. 相似文献
109.
二氧化碳(CO2)捕集是实现我国碳中和目标的重要手段.电化学介导胺再生(EMAR)CO2捕集系统是一种极具应用前景的碳捕集技术.为了进一步研究EMAR的电化学性能,利用H型电解池,对以乙醇胺(MEA)溶液为吸收剂,铜离子为金属配体的体系开展电化学行为研究.结果表明:阴极和阳极反应均是分步进行的,且均由扩散和电荷传递共同... 相似文献
110.
Improvement of water/resin wettability of graphite using carbon black nano particles coating via ink media 总被引:1,自引:0,他引:1
M. Sharif Sh. F. Golestani-Fard H. Sarpoolaky 《Journal of Alloys and Compounds》2009,482(1-2):361-365
Carbon coated graphite with high resin and water wettability characteristics could expand the refractory and carbon–carbon composites application in different fields. Improvement of water and resin wettability of graphite using carbon black coating via ink media is reported. Present method is based on preparing colloidal disperion of carbon black in ink followed by adding proper amount of graphite to the mixture which was dried and heat treated at 250 °C afterwards. The results showed that by controlling the amount of carbon black in ink and optimizing the process, a uniform coating with a thickness of 50 nm could be developed on the graphite surface.The wettability was evaluated by measuring contact angle and the microstructure of samples was characterized by optic microscope (OM) and scanning electron microscope (SEM). Also Raman spectroscopy was employed to support the results. The microstructure of coating was found to be uniform composed of carbon black nanoparticles. It was also demonstrated that the coating that could enhance the phenolic resin wettability was well. We also showed the coating could be applied on other ceramic particles such as MgO. 相似文献