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991.
992.
通过热压成型和注塑成型2种不同加工方法制备了碳纤维(CF)/聚丙烯(PP)导电复合材料,对比了2种复合材料的力学性能,结果表明注塑成型的CF/PP具有较高的拉伸强度和弹性模量。结合扫描电子显微镜观察,分析了这2种加工方法对CF/PP复合材料的微观结构和力学性能的影响。 相似文献
993.
Da Xiao Xiao Liang Xiwu Gao Jianxiu Yao Kun Yan Zhu 《International journal of molecular sciences》2014,15(4):6880-6896
We identified and characterized the TcLgl gene putatively encoding lethal giant larvae (Lgl) protein from the red flour beetle (Tribolium castaneum). Analyses of developmental stage and tissue-specific expression patterns revealed that TcLgl was constitutively expressed. To examine the role of TcLgl in insect development, RNA interference was performed in early (1-day) larvae, late (20-day) larvae, and early (1-day) pupae. The early larvae injected with double-stranded RNA of TcLgl (dsTcLgl) at 100, 200, and 400 ng/larva failed to pupate, and 100% mortality was achieved within 20 days after the injection or before the pupation. The late larvae injected with dsTcLgl at these doses reduced the pupation rates to only 50.3%, 36.0%, and 18.2%, respectively. The un-pupated larvae gradually died after one week, and visually unaffected pupae failed to emerge into adults and died during the pupal stage. Similarly, when early pupae were injected with dsTcLgl at these doses, the normal eclosion rates were reduced to only 22.5%, 18.0%, and 11.2%, respectively, on day 7 after the injection, and all the adults with abnormal eclosion died in two days after the eclosion. These results indicate that TcLgl plays an essential role in insect development, especially during their metamorphosis. 相似文献
994.
You-Lin Tain Li-Tung Huang Julie Y. H. Chan 《International journal of molecular sciences》2014,15(10):18484-18495
Melatonin is an endogenously produced indoleamine and secreted by the pineal gland. Melatonin has pleiotropic bioactivities and is involved in epigenetic regulation. Suboptimal conditions during maternal and perinatal phases can elicit epigenetic regulation of genes for nephrogenesis and reset physiological responses to develop programmed hypertension. This review discusses the early utility of melatonin to prevent programmed hypertension in later life by epigenetic regulation in the kidney, with an emphasis on: (1) the role of melatonin in epigenetic regulation; (2) the beneficial effects of melatonin on programmed hypertension; (3) epigenetic regulation of maternal melatonin therapy in different developmental windows of offspring kidneys analyzed by whole-genome RNA next-generation sequencing; and (4) current blocks in the application of melatonin in preventing programmed hypertension. 相似文献
995.
Hai‐Long Hu Dong‐Xu Yao Yong‐Feng Xia Kai‐Hui Zuo Yu‐Ping Zeng 《International Journal of Applied Ceramic Technology》2014,11(5):845-850
Porous Si3N4/SiC ceramics with high porosity were prepared via nitridation of Si powder, using SiC as the second phase and Y2O3 as sintering additive. With increasing SiC addition, porous Si3N4/SiC ceramics showed high porosity, low flexural strength, and decreased grain size. However, the sample with 20wt% SiC addition showed highest flexural strength and lowest porosity. Porous Si3N4/SiC ceramics with a porosity of 36–45% and a flexural strength of 107‐46MPa were obtained. The linear shrinkage of all porous Si3N4/SiC ceramics is below 0.42%. This study reveals that the nitridation route is a promising way to prepare porous Si3N4/SiC ceramics with favorable flexural strength, high porosity, and low linear shrinkage. 相似文献
996.
B. Ramezanzadeh S. Y. Arman M. Mehdipour 《Journal of Coatings Technology and Research》2014,11(5):727-737
The effects of lamellar aluminum (Al) and micaceous iron oxide (MIO) pigments on the anticorrosion properties of an epoxy zinc-rich coating were studied. To this end, the epoxy zinc-rich coatings containing 70% w/w spherical Zn particles, 60% w/w Zn + 10% w/w MIO, and 60% w/w Zn + 10% w/w Al were prepared. The electrochemical noise (ECN), potentiostatic polarization technique, and salt spray test were employed in order to investigate the anticorrosion performances of the zinc-rich coatings. The zinc-rich coatings morphologies were studied by scanning electron microscope (SEM) before and after the salt spray test. The open-circuit potential values were also measured at different immersion times. Results showed that MIO particles could enhance the cathodic protection duration of the zinc-rich coating by enhancing its barrier properties and reducing the zinc particles oxidation rate. It was also shown that Al particles reduced zinc-rich coating sacrificial behavior at short immersion times and increased it at long immersion times. Unlike MIO particles, Al particles behaved both as barrier and sacrificial pigment. 相似文献
997.
Chen Xu Xia Ma Shiwen Chen Meifeng Tao Lutao Yuan Yao Jing 《International journal of molecular sciences》2014,15(6):10855-10867
To improve the efficacy and safety of dural repair in neurosurgical procedures, a new dural material derived from bacterial cellulose (BC) was evaluated in a rabbit model with dural defects. We prepared artificial dura mater using bacterial cellulose which was incubated and fermented from Acetobacter xylinum. The dural defects of the rabbit model were repaired with BC membranes. All surgeries were performed under sodium pentobarbital anesthesia, and all efforts were made to minimize suffering. All animals were humanely euthanized by intravenous injection of phenobarbitone, at each time point, after the operation. Then, the histocompatibility and inflammatory effects of BC were examined by histological examination, real-time fluorescent quantitative polymerase chain reaction (PCR) and Western Blot. BC membranes evenly covered the surface of brain without adhesion. There were seldom inflammatory cells surrounding the membrane during the early postoperative period. The expression of inflammatory cytokines IL-1β, IL-6 and TNF-α as well as iNOS and COX-2 were lower in the BC group compared to the control group at 7, 14 and 21 days after implantation. BC can repair dural defects in rabbit and has a decreased inflammatory response compared to traditional materials. However, the long-term effects need to be validated in larger animals. 相似文献
998.
Qi-Ning Song Nan Xu Yao Tong Chen-Ming Huang Shou-Yu Sun Chen-Bo Xu Ye-Feng Bao Yong-Feng Jiang Yan-Xin Qiao Zhi-Yuan Zhu Zheng-Bin Wang 《金属学报(英文版)》2019,32(12):1470
The effect of sulphide(Na_2S) concentration(SC) on the corrosion and cavitation erosion behaviours of a cast nickel aluminium bronze(NAB) in 3.5% NaCl solution is investigated in this study.The results show that when the SC exceeds 50 ppm,the hydrogen evolution reaction dominates the cathodic process,and a limiting current region appears in the anodic branch of the polarisation curve due to the formation of a copper sulphide film,which is a diffusion-controlled process.After longterm immersion,the increased mass loss rate of NAB with the sulphide additions of 20 and 50 ppm is attributed to the less protective films,which contains a mixture of copper oxides and sulphides.Moreover,NAB undergoes severe localised corrosion(selective phase corrosion,SPC) at the β' phases and eutectoid microstructure α+κ_Ⅲ.By comparison,NAB undergoes general corrosion and a copper sulphide film is formed in 100 and 200 ppm sulphide solutions.Cavitation erosion greatly increases the corrosion rate of NAB in all solutions and causes a negative potential shift in 3.5% NaCl solution due to the film destruction.However,a positive potential shift occurs in the solutions with SC higher than 50 ppm due to the accelerated mass transfer of the cathodic process.The cavitation erosion mass loss rate of NAB increases with the increase of SC.The occurrence of severe SPC decreases the phase boundary cohesion and causes brittle fracture under the cavitation impact.The corrosion-enhanced erosion is the most predominant factor for the cavitation erosion damage when the SC exceeds 50 ppm. 相似文献
999.
The dynamic mechanical relaxation behavior of Ti_(36.2)Zr_(30.3)Cu_(8.3)Fe_4Be_(21.2) bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy. The mechanical relaxation behavior was analyzed in the framework of quasi-point defects model. The experimental results demonstrate that the atomic mobility of the metallic glass is closely associated with the correlation factor χ. The physical aging below the glass transition temperature T g shows a non-Debye relaxation behavior, which could be well described by stretched Kohlrausch exponential equation. The Kohlrausch exponent β_(aging) reflects the dynamic heterogeneities of the metallic glass. Both concentration of "defects" and atomic mobility decrease caused by the in situ successive heating during the mechanical spectroscopy experiments. 相似文献
1000.
Y.C. Gu G.S. Song J. Huang Y. Wang S.Y. Chen 《International Journal of Cast Metals Research》2019,32(5-6):295-303
ABSTRACTThe comparative studies of grain refinement of commercial purity Mg by CaO/Ca addition have been investigated by using TP-1 tests, optical microscope, XRD characterisation and TEM (STEM) observation along with EDX analysis. Experimental results showed that Ca/CaO addition significantly refines the grain structure of commercial purity Mg. Compared with Ca addition, CaO exhibits finer grain size and the average grain size remains invariable with further CaO addition. CaO addition is readily reduced to Ca by Mg melt and forms Mg2Ca on the surface of MgO particles. First-principle calculations were used to understand the nucleation of Mg2Ca layer by a coherent interface model calculating the work of adhesion and the interface energy between Mg2Ca and α-Mg. The combination of experiments and calculations showed that the formation of Mg2Ca layer on MgO facilitates the nucleation of α-Mg and then refines the grain structure by Ca or CaO addition. 相似文献