全文获取类型
收费全文 | 1391篇 |
免费 | 92篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 28篇 |
综合类 | 4篇 |
化学工业 | 297篇 |
金属工艺 | 30篇 |
机械仪表 | 42篇 |
建筑科学 | 32篇 |
能源动力 | 95篇 |
轻工业 | 196篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
武器工业 | 1篇 |
无线电 | 139篇 |
一般工业技术 | 343篇 |
冶金工业 | 67篇 |
原子能技术 | 26篇 |
自动化技术 | 189篇 |
出版年
2024年 | 2篇 |
2023年 | 33篇 |
2022年 | 105篇 |
2021年 | 124篇 |
2020年 | 86篇 |
2019年 | 85篇 |
2018年 | 105篇 |
2017年 | 76篇 |
2016年 | 82篇 |
2015年 | 48篇 |
2014年 | 69篇 |
2013年 | 116篇 |
2012年 | 72篇 |
2011年 | 85篇 |
2010年 | 40篇 |
2009年 | 45篇 |
2008年 | 36篇 |
2007年 | 39篇 |
2006年 | 22篇 |
2005年 | 28篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 20篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1966年 | 1篇 |
排序方式: 共有1498条查询结果,搜索用时 15 毫秒
51.
Adil Farooq Arfa Iqbal Nosheen Fatima Rana Misha Fatima Tuba Maryam Farhat Batool Zahra Rehman Farid Menaa Shabia Azhar Afrah Nawaz Faheem Amin Zuhair M. Mohammedsaleh Salma Saleh Alrdahe 《International journal of molecular sciences》2022,23(6)
Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the ‘thin-film hydration’ method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery. 相似文献
52.
M. Iqbal 《Solar Energy》1979,23(2):169-173
Empirical equations have been developed which correlate the monthly average daily horizontal diffuse and beam radiation with the fraction of maximum possible number of bright sunshine hours. These correlations are based on measured data from three widely spread Canadian stations.Depending upon whether or not the total horizontal radiation is known, the two correlations for the diffuse radiation are: .The correlation for beam radiation is: . 相似文献
53.
54.
In this paper an approach for the dynamic modelling of polymer electrolyte membrane fuel cells is presented. A mathematical formulation based on empirical equations is discussed and several features, exhibiting dynamic phenomena, are investigated. A generalized steady state fuel cell model is extended for the development of a method for dynamic electrochemical analysis. Energy balance and reactant flow dynamics are also explained through physical and empirical relationships. A well‐researched system (Ballard MK5‐E stack based PGS‐105B system) is considered in order to understand the operation of a practical fuel cell unit. Matlab‐SIMULINKTM has been used in simulating the models. The proposed method appears to be relatively simple and consequently requires less computation time. Simulation results are compared with available experimental findings and a good match has been observed. 相似文献
55.
A Flavanone and Two Phenolic Acids from Chrysanthemum morifolium with Phytotoxic and Insect Growth Regulating Activity 总被引:2,自引:0,他引:2
Beninger CW Abou-Zaid MM Kistner AL Hallett RH Iqbal MJ Grodzinski B Hall JC 《Journal of chemical ecology》2004,30(3):589-606
Leaves of Chrysanthemum morifolium cv. Ramat were extracted sequentially with hexane, ethyl acetate, and methanol. The methanol fraction, when incorporated into artificial diet was found to reduce the growth of cabbage looper (Trichoplusia ni Hubner) larvae at concentrations between 500 and 5000 ppm of diet. Fractionation of the methanol extract on a Sephadex column yielded five fractions, three of which reduced the weight of larvae relative to the control. One fraction was analyzed using high performance liquid chromatography (HPLC) and found to contain three main constituents. These compounds were purified using a combination of gel permeation chromatography on Sephadex LH20 and HPLC, and analyzed by 1H and 13CNMR as well as undergoing chemical and physical analyses. The compounds were identified as: 1, chlorogenic acid (5-O-caffeoylquinic acid); 2, 3,5-O-dicaffeoylquinic acid; and 3, 3', 4',5-trihydroxyflavanone7-O-glucuronide (eriodictyol7-O-glucuronide). At concentrations between 100 to 1000 ppm these compounds reduced both growth and photosynthesis of Lemna gibba L. with the order of efficacy being: flavanone > chlorogenic acid > 3,5-O-dicaffeoylquinic acid. Furthermore, when incorporated separately into artificial diet these compounds, at 10 to 1000 ppm, enhanced or reduced growth of the cabbage looper (Trichoplusia ni) and gypsy moth (Lymantria dispar L.). 相似文献
56.
Iqbal Mokhtar Mohd Yazid Yahya Mohammed Rafiq Abdul Kadir Mohd Faisal Kambali 《Polymer-Plastics Technology and Engineering》2013,52(11):1140-1146
The aim of this study was to investigate the performance of UHMWPE/HDPE-reinforced kenaf, basalt and hybrid kenaf/basalt composites. Mechanical testing of these samples was carried out such as tensile, flexural (three-point bending) and an impact test (Charpy). Pure resin (UHMWPE/HDPE) samples were tested and compare with reinforced 10% weight fraction of kenaf, basalt and hybrid kenaf/basalt samples to identifying their contribution and potential in this new composite material. UHMWPE/ HDPE sample was produced in constant ratio 60:40 respectively via extrusion process. Basalt reinforced UHMWPE/HDPE generates the highest elastic modulus result compared to kenaf and hybrid kenaf/basalt as a reinforcement material. The tensile results of kenaf reinforcement UHMWPE/HDPE samples are significantly higher (20%) than pure blend resin, which is an indication for good performance of kenaf, basalt and hybrid kenaf/basalt to be used in UHMWPE/HDPE-blend polymers. The flexural and Charpy strengths show the drawback results, where performance of polymer is reduced 5% with the absence of kenaf. It can be concluded that kenaf, basalt and hybrid kenaf/basalt fiber successfully increase the UHMWPE/HDPE blends performance especially under tensile loading. 相似文献
57.
Muhammad Kashif Md Eaqub Ali Syed M Usman Ali Uda Hashim Sharifah Bee Abd Hamid 《Nanoscale research letters》2013,8(1):68
ZnO nanorods were synthesized using a low-cost sol-gel spin coating technique. The synthesized nanorods were consisted of hexagonal phase having c-axis orientation. SEM images reflected perpendicular ZnO nanorods forming bridging network in some areas. The impact of different hydrogen concentrations on the Pd-sensitized ZnO nanorods was investigated using an impedance spectroscopy (IS). The grain boundary resistance (Rgb) significantly contributed to the sensing properties of hydrogen gas. The boundary resistance was decreased from 11.95 to 3.765 kΩ when the hydrogen concentration was increased from 40 to 360 ppm. IS gain curve showed a gain of 6.5 for 360 ppm of hydrogen at room temperature. Nyquist plot showed reduction in real part of impedance at low frequencies on exposure to different concentrations of hydrogen. Circuit equivalency was investigated by placing capacitors and resistors to identify the conduction mechanism according to complex impedance Nyquist plot. Variations in nanorod resistance and capacitance in response to the introduction of various concentrations of hydrogen gas were obtained from the alternating current impedance spectra. 相似文献
58.
Chen Guang Yu Vimala Bondada Hina Iqbal Kate L. Moore John C. Gensel Subbarao Bondada James W. Geddes 《International journal of molecular sciences》2022,23(1)
Microglia/astrocyte and B cell neuroimmune responses are major contributors to the neurological deficits after traumatic spinal cord injury (SCI). Bruton tyrosine kinase (BTK) activation mechanistically links these neuroimmune mechanisms. Our objective is to use Ibrutinib, an FDA-approved BTK inhibitor, to inhibit the neuroimmune cascade thereby improving locomotor recovery after SCI. Rat models of contusive SCI, Western blot, immunofluorescence staining imaging, flow cytometry analysis, histological staining, and behavioral assessment were used to evaluate BTK activity, neuroimmune cascades, and functional outcomes. Both BTK expression and phosphorylation were increased at the lesion site at 2, 7, 14, and 28 days after SCI. Ibrutinib treatment (6 mg/kg/day, IP, starting 3 h post-injury for 7 or 14 days) reduced BTK activation and total BTK levels, attenuated the injury-induced elevations in Iba1, GFAP, CD138, and IgG at 7 or 14 days post-injury without reduction in CD45RA B cells, improved locomotor function (BBB scores), and resulted in a significant reduction in lesion volume and significant improvement in tissue-sparing 11 weeks post-injury. These results indicate that Ibrutinib exhibits neuroprotective effects by blocking excessive neuroimmune responses through BTK-mediated microglia/astroglial activation and B cell/antibody response in rat models of SCI. These data identify BTK as a potential therapeutic target for SCI. 相似文献
59.
Synthesis and characterization of novel curcumin based polyurethanes varying diisocyanates structure
Kashif Mahmood Iqra Noreen Muhammad Riaz Mohammad Zuber Mahwish Salman Saima Rehman Khalid Mahmood Zia 《Journal of Polymer Research》2016,23(11):233
In this research work, novel polyurethanes (PUs) based on blends of curcumin/1,4-butane diol (BDO) by varying the structure of diisocyanates were prepared following step growth polymerization. Structural study of blends and various diisocyanates based PU through Fourier Transform Infrared (FTIR) spectroscopy confirmed the incorporation of curcumin into the backbone of the PU. The scanning electron microscopic (SEM) study confirmed the well dispersion of incorporated curcumin and homogeneity of surface of synthesized samples. The SEM results also indicated that surface morphology of synthesized samples much dependent on diisocynates structure. Moreover SEM images inferred that phase separation is more pronounced in aromatic diisocyanate based PU. The anti-bacterial and anti-fungal tests were performed against different strains in order to determine the biocompatibility of the curcumin based PU. The antimicrobial activity results revealed that the material having aromatic diisocyanate are more biocompatible than the aliphatic diisocyanates in the PU structure. On the whole, this work is actually a step towards the generation of novel biocompatible materials preferably useful for biomedical applications. 相似文献
60.
Raz Muhammad Yaseen Iqbal Ian M Reaney 《Journal of the American Ceramic Society》2016,99(6):2089-2095
Solid solutions of (1?x)BaTiO3–xBi(Mg2/3Nb1/3)O3 (0 ≤ x ≤ 0.6) were prepared via a standard mixed‐oxide solid‐state sintering route and investigated for potential use in high‐temperature capacitor applications. Samples with 0.4 ≤ x ≤ 0.6 showed a temperature independent plateau in permittivity (εr). Optimum properties were obtained for x = 0.5 which exhibited a broad and stable relative εr ~940 ± 15% from ~25°C to 550°C with a loss tangent <0.025 from 74°C to 455°C. The resistivity of samples increased with increasing Bi(Mg2/3Nb1/3)O3 concentration. The activation energies of the bulk were observed to increase from 1.18 to 2.25 eV with an increase in x from 0 to 0.6. These ceramics exhibited excellent temperature stable dielectric properties and are promising candidates for high‐temperature multilayer ceramic capacitors for automotive applications. 相似文献