全文获取类型
收费全文 | 94041篇 |
免费 | 17672篇 |
国内免费 | 2966篇 |
专业分类
电工技术 | 4107篇 |
技术理论 | 11篇 |
综合类 | 4149篇 |
化学工业 | 26079篇 |
金属工艺 | 3557篇 |
机械仪表 | 4068篇 |
建筑科学 | 6118篇 |
矿业工程 | 1731篇 |
能源动力 | 2270篇 |
轻工业 | 11934篇 |
水利工程 | 1277篇 |
石油天然气 | 3122篇 |
武器工业 | 366篇 |
无线电 | 13220篇 |
一般工业技术 | 17466篇 |
冶金工业 | 3228篇 |
原子能技术 | 620篇 |
自动化技术 | 11356篇 |
出版年
2024年 | 305篇 |
2023年 | 1036篇 |
2022年 | 1859篇 |
2021年 | 2692篇 |
2020年 | 3258篇 |
2019年 | 4681篇 |
2018年 | 4738篇 |
2017年 | 5231篇 |
2016年 | 5488篇 |
2015年 | 6172篇 |
2014年 | 6675篇 |
2013年 | 8197篇 |
2012年 | 6417篇 |
2011年 | 6168篇 |
2010年 | 5836篇 |
2009年 | 5501篇 |
2008年 | 5066篇 |
2007年 | 4797篇 |
2006年 | 4440篇 |
2005年 | 3638篇 |
2004年 | 3028篇 |
2003年 | 3261篇 |
2002年 | 3622篇 |
2001年 | 3062篇 |
2000年 | 2458篇 |
1999年 | 1761篇 |
1998年 | 972篇 |
1997年 | 804篇 |
1996年 | 733篇 |
1995年 | 605篇 |
1994年 | 526篇 |
1993年 | 383篇 |
1992年 | 280篇 |
1991年 | 215篇 |
1990年 | 200篇 |
1989年 | 136篇 |
1988年 | 92篇 |
1987年 | 67篇 |
1986年 | 63篇 |
1985年 | 28篇 |
1984年 | 31篇 |
1983年 | 24篇 |
1982年 | 27篇 |
1981年 | 16篇 |
1980年 | 28篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1976年 | 12篇 |
1975年 | 7篇 |
1951年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Journal of Porous Materials - Aiming at the poor heat conduction performance of porous MIL-101 applied in adsorption cooling process, few layer graphene (FLG) was selected as a promising thermal... 相似文献
102.
Highly conductive transparent aluminium-doped ZnO (ZnO:A1) films were successfully deposited by CW-CO2 laser-induced evaporation. Optimisation of evaporation parameters was based on laser power, substrate temperature, O2 partial pressure in the vacuum chamber and amount of Al in the ZnO source pellet. ZnO:A1 films with an electrical resistivity as low as 6.6 × 10−2Ω·cm and an optical transmission of 80% at 500nm were obtained at laser power of 15 W, substrate temperature of about 200°C, O2 partial pressure of 6—7 × 10−4 Torr and 5wt.% Al. Conductivity of ZnO films can be increased one order via Al-doping in ZnO films. The films obtained by laser-induced evaporation have compared quite favorably with the high quality films obtained by sputtering. 相似文献
103.
104.
105.
按照财政部国库管理制度改革统一要求,鄂尔多斯市开展了国库集中支付试点工作。运行过程中,一些阻碍改革运行的问题引起笔者的思考。文中介绍了笔者当地实施改革试点存在的突出问题,如电脑网络不完善情况下国库集中支付操作难以运行、预算编制不能满足国库支付的基本要求、国库支付系统与银行业务收支不兼容、财政收支进度不一致、财政财力供给不足给集中支付造成瓶颈制约、政策法规出台滞后、改革现行的财政支出管理体系阻力很大、政府采购项目及资金审批程序不规范等。笔者并结合问题大胆提出了自己对推进的改革的措施和建议,即加强组织领导、强化理论学习借鉴、彻底清理银行账户、加强网络建设、制定切实可行的改革方案及配套办法、加快行政审批服务制度的改革、改革传统发放工资制度、进一步规范政府采购制度。 相似文献
106.
To impart easy‐care properties to cellulose‐containing fabrics along with avoiding any harmful effects of formaldehyde on both the health and the environment, attempts have been made to use citric acid (CA) as an ester crosslinking agent along with different catalytic systems in the absence and presence of certain additives. Further, fixation conditions, type of crosslinking agent, as well as type of substrate have been studied. Results revealed that the enhancement in carboxyl content, performance properties, and the decrease in tear strength (TS) as well as in whiteness indices (WI) of the finished fabric samples were increased by increasing CA concentration up to 80 g/L and by raising thermofixation temperature from 140 up to 180°C for 90 s. Inclusion of triethanolamine hydrochloride (TEA. HCl), decreased the carboxyl content, TS, color strength K/S, as well as oily stain release rating (SRR) of the finished fabric samples along with an increase in bound nitrogen (%N), wrinkle recovery angle WRA, and an improvement in WI without affecting the durable press rating (DP). Within the range examined (0–30 g/L), increasing PEG‐600 concentration improved the wet resiliency, TS, as well as WI properties of the finished samples. Increasing DMDHEU ratio in the CA/DMDHEU crosslinking system gave rise to an increase in %N, WRA (dry and wet), DP, as well as in free CH2O of finished fabrics, along with a slight improvement in WI values. On the other hand, the TS, carboxyl content, K/S, SRR values of the finished fabric samples were lower at a higher DMDHEU ratio. Increase in carboxyl content, %N, WRA (dry and wet), DP and SRR, as well as extent of post dyeing (K/S) of the treated fabric samples upon using different ester crosslinking agents followed the descending order: citric acid > pyromellitic dianhydride. The opposite holds true for the TS, and WI values. Among the esterifying catalysts used, and for a given set of finishing conditions, NaH2PO2 · H2O proved to be the most effective one, and the following order of effectiveness may be drawn: NaH2PO2 · H2O > K2HPO4 > Na3–citrate > Na2–tartrate. Inclusion of silicone softener in the finishing formulation brought about an improvement in softeness degree, WRA, %N, DP, TS as well as K/S values along with a decrease in carboxyl content, SRR, and WI values of the treated fabric samples, regardless of the used silicone softener.The performance properties of the finished fabric samples were determined by the type and nature of the substrate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2243–2253, 2002 相似文献
107.
A series of phosphorus‐containing, wholly aromatic thermotropic copolyesters from acetylated 2‐(6‐oxide‐6H‐dibenz〈c,e〉〈1,2〉oxa phosphorin‐6‐yl)‐1,4‐dihydroxy phenylene, p‐acetoxybenzoic acid, terephthalic acid, and isophthalic acid were prepared by melting polycondensation. The structure and basic properties of the polymers, such as the glass‐transition temperature (Tg), melting temperature (Tm), thermal stability, crystallinity, and liquid crystallinity, were investigated with Fourier transform infrared, elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis, wide‐angle X‐ray diffraction, and hot‐stage polarizing optical microscopy. The copolyesters had relatively high Tg values ranging from 183 to 192°C. The Tm values obtained from DSC curves for samples P‐20 and P‐25 were 290 and 287°C, respectively (where the number in the sample name indicates the molar fraction of the phosphorus‐containing monomer in the reactants). The initial flow temperatures of other samples observed with hot‐stage polarizing microscopy were 271–290°C. The 5% degradation temperatures in nitrogen ranged from 431 to 462°C, and the char yields at 640°C were 41–52%. All the copolyesters, except P‐40, were thermotropic and nematic. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1278–1284, 2002 相似文献
108.
Cotton and cotton/polyester fabrics were treated against microbial attack by applying a formulation based essentially on ZnO under high‐energy radiation and thermal curing. To achieve the homogeneity and the reactivity of the treating formulation, a binder (Impron MTP) and a dispersing agent (Setamol WS) were used with ZnO. The antimicrobial property of the fabrics was evaluated, in terms of mechanical properties, by a soil burial test. Moreover, the effect of antimicrobial finishing on the dyeing properties in terms of color strength was investigated. It was found that the best composition that affords the best antimicrobial protection to cotton fabrics contains 2% ZnO, 2% binder, and 1% dispersing agents. For the cotton/polyester blend, the best results were achieved at the same conditions except the ZnO was 1%. It was found that the treatment under the effect of electron‐beam irradiation is better than that of gamma irradiation and thermal curing. The results showed that when the finishing process was carried out before dyeing with a reactive dye, it affects the color strength rather than performing the finishing after the dyeing process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1129–1137, 2003 相似文献
109.
110.