全文获取类型
收费全文 | 427693篇 |
免费 | 14157篇 |
国内免费 | 6189篇 |
专业分类
电工技术 | 12846篇 |
技术理论 | 9篇 |
综合类 | 8833篇 |
化学工业 | 66601篇 |
金属工艺 | 27548篇 |
机械仪表 | 20792篇 |
建筑科学 | 14428篇 |
矿业工程 | 7589篇 |
能源动力 | 7873篇 |
轻工业 | 19605篇 |
水利工程 | 7510篇 |
石油天然气 | 20645篇 |
武器工业 | 1072篇 |
无线电 | 39516篇 |
一般工业技术 | 93494篇 |
冶金工业 | 42549篇 |
原子能技术 | 13948篇 |
自动化技术 | 43181篇 |
出版年
2022年 | 5159篇 |
2021年 | 8147篇 |
2020年 | 6370篇 |
2019年 | 6158篇 |
2018年 | 14817篇 |
2017年 | 15628篇 |
2016年 | 13362篇 |
2015年 | 8434篇 |
2014年 | 11765篇 |
2013年 | 17827篇 |
2012年 | 17523篇 |
2011年 | 23186篇 |
2010年 | 20154篇 |
2009年 | 19560篇 |
2008年 | 19909篇 |
2007年 | 20429篇 |
2006年 | 12999篇 |
2005年 | 13243篇 |
2004年 | 11003篇 |
2003年 | 10672篇 |
2002年 | 9766篇 |
2001年 | 8618篇 |
2000年 | 8030篇 |
1999年 | 6973篇 |
1998年 | 9250篇 |
1997年 | 7502篇 |
1996年 | 5937篇 |
1995年 | 5089篇 |
1994年 | 4635篇 |
1993年 | 4531篇 |
1992年 | 4056篇 |
1991年 | 4033篇 |
1990年 | 4069篇 |
1989年 | 3896篇 |
1988年 | 3717篇 |
1987年 | 3651篇 |
1986年 | 3472篇 |
1985年 | 3601篇 |
1984年 | 3498篇 |
1983年 | 3384篇 |
1981年 | 3280篇 |
1980年 | 3321篇 |
1979年 | 3552篇 |
1978年 | 3771篇 |
1977年 | 3762篇 |
1976年 | 4215篇 |
1975年 | 3522篇 |
1974年 | 3586篇 |
1973年 | 3601篇 |
1972年 | 3304篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Theoretical Foundations of Chemical Engineering - The results of numerical modeling of the heat and mass transfer of drops during drying of a liquid under the conditions of... 相似文献
52.
Osipenko M. A. Kharitonov D. S. Makarova I. V. Romanovsky V. I. Kurilo I. I. 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(3):550-558
Protection of Metals and Physical Chemistry of Surfaces - The dependences of the protective properties of the anodic oxide coatings on the AD31 aluminum alloy surface modified with nitrates of... 相似文献
53.
Shiming Xie Chen Song Zexin Yu Shaowu Liu Frédéric Lapostolle Didier Klein Chunming Deng Min Liu Hanlin Liao 《Journal of the European Ceramic Society》2021,41(1):535-543
Suspension plasma spraying (SPS) as a potential technique to prepare thermal barrier coatings (TBCs) has been attracting more and more attention. However, most reports on SPS were carried out in the atmosphere. Given the unique features of in-flight particles and plasma jets under low pressure, the resulting coatings are expected to be different from those under atmospheric pressure. In this article, yttria-stabilized zirconia (YSZ) thermal barrier coatings were prepared using suspension plasma spraying under different environmental pressures. The results show that as the environmental pressure decreased, the column-like structural coating turned into a vertical crack segmented structure, as well as a dramatic decrease in surface roughness. More nanoparticle agglomerates were formed in the coating under lower environmental pressures. The real porosity of the coating increased with a decrease in environmental pressure. 相似文献
54.
55.
Xuewu Li Lin Zhang Tian Shi Weining Yu Jinhui Shao Xuegang Zhou Yuxing He Binbin Zhang 《工业材料与腐蚀》2021,72(5):951-959
Ti-based amorphous metallic glasses have excellent mechanical, physical, and chemical properties, which is an important development direction and research hotspot of metal composite reinforcement. As a stable, simple, efficient, and large-scale preparation technology of metallic powders, the gas atomization process provides an effective way of preparing amorphous metallic glasses. In this study, the controllable fabrication of a Ti-based amorphous powder, with high efficiency, has been realized by using gas atomization. The scanning electron microscope, energy-dispersive spectrometer, and X-ray diffraction are used to analyze surface morphology, element distribution, and phase structure, respectively. A microhardness tester is used to measure the mechanical property. An electrochemical workstation is used to characterize corrosion behavior. The results show that as-prepared microparticles are more uniform and exhibit good amorphous characteristics. The mechanical test shows that the hardness of amorphous powder is significantly increased as compared with that before preparation, which has the prospect of being an important part of engineering reinforced materials. Further electrochemical measurement shows that the corrosion resistance of the as-prepared sample is also significantly improved. This study has laid a solid foundation for expanding applications of Ti-based metallic glasses, especially in heavy-duty and corrosive domains. 相似文献
56.
Golubev N. V. Ignat’eva E. S. Maurus A. A. Ziyatdinova M. Z. Lopatina E. V. Lorenzi R. Paleari A. Sigaev V. N. 《Glass and Ceramics》2021,77(11-12):415-418
Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence... 相似文献
57.
Ruizhi Hu Chen Dai Chunmei Wang Jie Lin Hui Hu Zhifang Li Han Lin Li Ding Yu Chen Bo Zhang 《Advanced functional materials》2021,31(25):2101660
As an anticancer drugs, arsenic trioxide (ATO) has been certified to efficiently treat refractory acute promyelocytic leukemia (APL). Unfortunately it suffers from limited therapeutic potency for solid tumors due to its in vivo restricted administration dose and rapid renal clearance. Herein, distinct 2D arsenic-phosphorus (AsP) nanosheets are engineered by adopting an alloy strategy followed by exfoliation, which can confine toxic arsenic into AsP crystals, thus significantly improving the biosafety and biocompatibility of arsenic-based chemotherapeutic drugs. Of particular note, the high light absorption and strong photothermal-conversion efficiency (37.6%) in the second near infrared biowindow (NIR-II) of AsP nanosheets not only endow them with desirable contrast-enhanced photoacoustic imaging properties, but also achieve efficient local tumor hyperthermia, which further synergistically triggers the in-situ transformation from low toxic/nontoxic AsP crystals into highly toxic arsenic species, exerting a strong arsenic-mediated antineoplastic effect. Both in vitro and in vivo data verify the synergy between photonic therapy in NIR-II and enhanced chemotherapy as enabled by AsP nanosheets, paving the way for efficient nanomedicine-enabled arsenic-based chemotherapeutic tumor treatment. 相似文献
58.
T.V. Vakalova L.P. Devyashina Sh.M. Sharafeev N.P. Sergeev 《Ceramics International》2021,47(11):15282-15292
One of the drawbacks of fusible clays is the narrow sintering interval due to a sharp increase in the amount of iron-silicate melt at a temperature of 1000–1100 °C, which hardens in the form of a glass phase upon cooling. This leads to a relatively low mechanical strength of the calcined samples and causes the danger of melting the granular material surface from such clays during the firing process. To increase the strength of samples of fusible clays, the influence of diabase and granitoid rocks was considered. It was found that the strengthening effect of diabase and granitoid rock additives in an amount of 20–50% in a mixture with fusible clay is due to an increase of total content of the crystalline phase (mullite, cristobalite and residual quartz) from 18–20% in clays without additives to 22–28 % - in mixtures with diabase and to 28–34% - with granitoid additives) at a temperature of 1050–1100 °C. This increase is due to the activation of synthesis processes of secondary mullite and crystallization from alkali-rich feldspar melt of amorphous silica, released from the structure of clay minerals. The established influence of the igneous rocks used made it possible to develop compositions and propose process flow sheet for producing aluminosilicate proppants based on fusible clays. The use of granitoid and diabase rocks in an amount of 20–70% with fusible clays produces lightweight aluminosilicate proppants with bulk density of 1.40–1.46 g/cm3 at temperature range of 1050–1100 °C, which can endure destructive pressures up to 34.5–52 MPa. 相似文献
59.
Annette L. West Louise V. Michaelson Elizabeth A. Miles Richard P. Haslam Karen A. Lillycrop Ramona Georgescu Lihua Han Johnathan A. Napier Philip C. Calder Graham C. Burdge 《Lipids》2021,56(2):229-242
The phospholipid composition of lipoproteins is determined by the specificity of hepatic phospholipid biosynthesis. Plasma phospholipid 20:4n-6 and 22:6n-3 concentrations are higher in women than in men. We used this sex difference in a lipidomics analysis of the impact of endocrine factors on the phospholipid class and molecular species composition of fasting plasma from young men and women. Diester species predominated in all lipid classes measured. 20/54 Phosphatidylcholine (PtdCho) species were alkyl ester, 15/48 phosphatidylethanolamine (PtdEtn) species were alkyl ester, and 12/48 PtdEtn species were alkenyl ester. There were no significant differences between sexes in the proportions of alkyl PtdCho species. The proportion of alkyl ester PtdEtn species was greater in women than men, while the proportion of alkenyl ester PtdEtn species was greater in men than women. None of the phosphatidylinositol (PtdIns) or phosphatidylserine (PtdSer) molecular species contained ether-linked fatty acids. The proportion of PtdCho16:0_22:6, and the proportions of PtdEtn O-16:0_20:4 and PtdEtn O-18:2_20:4 were greater in women than men. There were no sex differences in PtdIns and PtdSer molecular species compositions. These findings show that plasma phospholipids can be modified by sex. Such differences in lipoprotein phospholipid composition could contribute to sexual dimorphism in patterns of health and disease. 相似文献
60.
Kruglikov S. S. Zagorskii D. L. Kolesnikov V. A. Doludenko I. M. Bedin S. A. 《Theoretical Foundations of Chemical Engineering》2021,55(5):942-951
Theoretical Foundations of Chemical Engineering - The effect of the electrolyte composition, mass-transfer conditions, pore diameter, interpore distance, and electric parameters on the formation of... 相似文献