全文获取类型
收费全文 | 10601篇 |
免费 | 1146篇 |
国内免费 | 403篇 |
专业分类
电工技术 | 171篇 |
综合类 | 621篇 |
化学工业 | 4820篇 |
金属工艺 | 533篇 |
机械仪表 | 166篇 |
建筑科学 | 184篇 |
矿业工程 | 415篇 |
能源动力 | 142篇 |
轻工业 | 2253篇 |
水利工程 | 35篇 |
石油天然气 | 479篇 |
武器工业 | 15篇 |
无线电 | 293篇 |
一般工业技术 | 1085篇 |
冶金工业 | 609篇 |
原子能技术 | 290篇 |
自动化技术 | 39篇 |
出版年
2024年 | 51篇 |
2023年 | 176篇 |
2022年 | 316篇 |
2021年 | 367篇 |
2020年 | 422篇 |
2019年 | 368篇 |
2018年 | 326篇 |
2017年 | 414篇 |
2016年 | 432篇 |
2015年 | 386篇 |
2014年 | 586篇 |
2013年 | 742篇 |
2012年 | 814篇 |
2011年 | 776篇 |
2010年 | 531篇 |
2009年 | 521篇 |
2008年 | 450篇 |
2007年 | 588篇 |
2006年 | 610篇 |
2005年 | 492篇 |
2004年 | 434篇 |
2003年 | 354篇 |
2002年 | 340篇 |
2001年 | 288篇 |
2000年 | 262篇 |
1999年 | 212篇 |
1998年 | 169篇 |
1997年 | 129篇 |
1996年 | 106篇 |
1995年 | 87篇 |
1994年 | 70篇 |
1993年 | 71篇 |
1992年 | 54篇 |
1991年 | 44篇 |
1990年 | 31篇 |
1989年 | 22篇 |
1988年 | 19篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 2篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1976年 | 2篇 |
1961年 | 1篇 |
1959年 | 4篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Intact and ovariectomized oxytocin (OT)-deficient (OT-/-) and wild-type (OT+/+) mice were tested for consumption of 0.5 M NaCl solution or tap water in a 2-bottle choice test. During 3 days of acclimation, voluntary ingestion of NaCl was equal between genotypes. After overnight fluid deprivation, intact OT-/- mice ingested 2 times more NaCl solution than OT+/+ mice in the 6th hr, but not the 1 st hr, after reintroduction of fluid. Ovariectomized mice consumed less than intact mice after overnight fluid deprivation. When a 0.2 M NaCl solution was administered for 6 days in ovariectomized mice, OT-/- mice voluntarily consumed greater amounts than OT+/+ mice. After overnight fluid deprivation, consumption by OT-/- mice was 3 times that of OT+/+ mice at 1 hr and 2-fold greater after 6 hr. Enhanced intake of NaCl-containing solutions in female OT-/- mice suggests that central OT may be an important inhibitor of sodium consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
12.
本文重点讨论了硫氰酸钠湿纺腈纶设备因钝化膜缺陷和Cl-侵入而产生孔蚀的机理及环境因素对孔蚀的影响,并针对产生孔蚀的主要原因提出了防护措施。 相似文献
13.
14.
钠水玻璃涂料的固化技术及其应用 总被引:3,自引:0,他引:3
崔中敏 《山东建筑工程学院学报》1996,11(3):103-106
论述了五种固化剂改性钠水玻璃的原理及在涂料中的应用,重点介绍了用可溶性金属盐必性钠水玻璃制作涂料的技术关键。 相似文献
15.
16.
Y. C. Wu Darning Feng W. F. Koch 《Journal of research of the National Institute of Standards and Technology》1991,96(6):757-762
Ionic interactions in the two systems NaCl-HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid) and NaCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic acid) have been studied in terms of their mutual influence on the respective activity coefficients of each component. Activity coefficients for each component of the two systems and for corresponding buffers are calculated from emf measurements of solutions containing NaCl, the aminosulfonic acid, and its conjugate base in a NalSE/solution/AgCl-Ag cell at 5, 15, 25, and 37 °C. 相似文献
17.
硫化钠在黑白钨加温精选中的应用研究 总被引:3,自引:0,他引:3
介绍了柿竹园黑白钨混合粗精矿加温精选中 ,添加硫化钠与水玻璃混合剂比单一添加水玻璃能更有效地使白钨矿与萤石等含钙矿物及脉石矿物分离。论述了硫化钠在加温精选中的作用效果并探讨了其作用机理 相似文献
18.
B.M. Naveena A.R. Sen M. Muthukumar S. Vaithiyanathan Y. Babji 《Journal of food science》2006,71(9):S603-S608
ABSTRACT: The aim of this study was to determine the effect of adding 3.3% sodium lactate (SL), 0.25% calcium lactate (CL), and 1.65% SL along with 0.125% CL (SL+CL) on the physicochemical properties, cooking characteristics, and microbiological quality of microwave-cooked chicken patties compared to control (no added lactates). The addition of lactates did not affect the proximate composition of cooked chicken patties. The pH of CL- or SL+CL-containing patties was significantly ( P < 0.05) reduced compared to control or SL patties. The SL-containing patties had lower ( P < 0.05) a w values compared to control or CL patties. The CL- or SL+CL-containing patties had lower denatured myoglobin and higher ( P < 0.05) cooking yield, surface redness (CIE a *), and chroma values. However, addition of CL alone resulted in higher total expressible fluid, indicating lower water-holding capacity. The CL-containing patties exhibited lower Warner–Bratzler shear force values and higher ( P < 0.05) penetrometer reading compared to the SL-containing patties, indicating soft texture. Thiobarbituric acid (TBA) values were significantly ( P < 0.05) reduced in all lactate-containing patties compared to control up to the 7th day of refrigerated storage under aerobic conditions. No difference ( P > 0.05) was observed in aerobic plate counts between control and lactate-added patties during 28-d storage. 相似文献
19.
T. RONALD A. MAGEE CAROLE P.D. WILKINSON 《International Journal of Food Science & Technology》1992,27(5):541-549
Investigation of the effects of varying air velocity, slice thickness, and pre-treatment with sodium chloride solutions and surface active agents on drying potato slices indicated that the drying occurred entirely in the falling rate period and was controlled by the mechanism of liquid diffusion. The rate of drying, and therefore the diffusion coefficients, increased with the addition of sodium chloride and surface active agents. Diffusion coefficients were also influenced by air velocity and slice thickness, suggesting that the rate of drying of potato slices is controlled by a combination of internal and external resistances. 相似文献
20.
The influence of NaCl and CO2 on the atmospheric corrosion of magnesium alloy AZ91 is studied in the laboratory. Samples were exposed under carefully controlled air and flow conditions; the relative humidity was 95%, the temperature was 22.0°C and the concentration of CO2 was < 1 ppm or 350 ppm. Different amounts of sodium chloride (0–70 μg/cm2) were added before exposure. The corrosion products were analyzed by gravimetry, ion chromatography, X‐ray diffraction and scanning electron microscopy. Mass gain and metal loss results are reported. The combination of high humidity and NaCl is very corrosive towards AZ91. However, the NaCl‐induced corrosion is inhibited by ambient concentrations of CO2. Exposure in the absence of CO2 gives rise to heavy pitting, with brucite, Mg(OH)2, being the dominant corrosion product. In the presence of CO2 a layer of hydrated magnesium hydroxy carbonate, Mg5(CO3)4(OH)2 · 5 H2O forms. A tentative corrosion mechanism is presented that explains the behavior in the two environments. 相似文献