全文获取类型
收费全文 | 2075篇 |
免费 | 88篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 24篇 |
综合类 | 7篇 |
化学工业 | 575篇 |
金属工艺 | 73篇 |
机械仪表 | 95篇 |
建筑科学 | 27篇 |
矿业工程 | 2篇 |
能源动力 | 157篇 |
轻工业 | 152篇 |
水利工程 | 8篇 |
石油天然气 | 10篇 |
无线电 | 117篇 |
一般工业技术 | 532篇 |
冶金工业 | 159篇 |
原子能技术 | 14篇 |
自动化技术 | 214篇 |
出版年
2024年 | 5篇 |
2023年 | 26篇 |
2022年 | 53篇 |
2021年 | 55篇 |
2020年 | 69篇 |
2019年 | 52篇 |
2018年 | 80篇 |
2017年 | 73篇 |
2016年 | 72篇 |
2015年 | 70篇 |
2014年 | 83篇 |
2013年 | 176篇 |
2012年 | 114篇 |
2011年 | 165篇 |
2010年 | 98篇 |
2009年 | 94篇 |
2008年 | 93篇 |
2007年 | 89篇 |
2006年 | 59篇 |
2005年 | 54篇 |
2004年 | 39篇 |
2003年 | 47篇 |
2002年 | 37篇 |
2001年 | 15篇 |
2000年 | 22篇 |
1999年 | 24篇 |
1998年 | 43篇 |
1997年 | 30篇 |
1996年 | 25篇 |
1995年 | 27篇 |
1994年 | 28篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 20篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 13篇 |
1971年 | 4篇 |
排序方式: 共有2166条查询结果,搜索用时 31 毫秒
91.
Tom P. Wyatt An‐Ting Chien Satish Kumar Donggang Yao 《Polymer Engineering and Science》2014,54(12):2839-2847
This article describes a new gel‐spinning process for making high‐strength poly(ethylene oxide) (PEO) fibers. The PEO gel‐spinning process was enabled through an oligomer/polymer blend in place of conventional organic solvents, and the gelation and solvent‐like properties were investigated. A 92/8 wt% poly(ethylene glycol)/PEO gel exhibited a melting temperature around 45°C and was highly stretchable at room temperature. Some salient features of a gel‐spun PEO fiber with a draw ratio of 60 are tensile strength at break = 0.66 ± 0.04 GPa, Young's modulus = 4.3 ± 0.1 GPa, and a toughness corresponding to 117 MJ/m3. These numbers are significantly higher than those previously reported. Wide‐angle x‐ray diffraction of the high‐strength fibers showed good molecular orientation along the fiber direction. The results also demonstrate the potential of further improvement of mechanical properties. POLYM. ENG. SCI., 54:2839–2847, 2014. © 2014 Society of Plastics Engineers 相似文献
92.
Camphor sulfonic acid (CSA) doped PANi–SnO2 hybrid nanocomposites were synthesized by solid-state synthesis route with varying amounts (10–50%) of CSA. X-ray diffraction studies have proven the successful incorporation of CSA into the polyaniline–SnO2 hybrid nanocomposites and the results are also supported by microstructural analysis. UV–visible and Fourier infrared spectroscopy studies have provided insight into the electronic interaction between the CSA, polyaniline, and SnO2. The room temperature dc electrical conductivity of CSA-doped PANi–SnO2 hybrid nanocomposite films were observed to depend on the amount of CSA doping and the morphology. 相似文献
93.
Satish Kumar Vemuri Satyajit Halder Rajkiran Reddy Banala Hari Krishnreddy Rachamalla Vijaya Madhuri Devraj Chandra Shekar Mallarpu Uttam Kumar Neerudu Ravikiran Bodlapati Sudip Mukherjee Subbaiah Goli Peda Venkata Gurava Reddy Annapareddy Venkata Malarvilli Thakkumalai Kuladip Jana 《International journal of molecular sciences》2022,23(4)
Background: Breast cancer is the most common cancer in women globally, and diagnosing it early and finding potential drug candidates against multi-drug resistant metastatic breast cancers provide the possibilities of better treatment and extending life. Methods: The current study aimed to evaluate the synergistic anti-metastatic activity of Curcumin (Cur) and Paclitaxel (Pacli) individually, the combination of Curcumin–Paclitaxel (CP), and also in conjugation with gold nanoparticles (AuNP–Curcumin (Au-C), AuNP–Paclitaxel (Au-P), and AuNP–Curcumin–Paclitaxel (Au-CP)) in various in vitro and in vivo models. Results: The results from combination treatments of CP and Au-CP demonstrated excellent synergistic cytotoxic effects in triple-negative breast cancer cell lines (MDA MB 231 and 4T1) in in vitro and in vivo mouse models. Detailed mechanistic studies were performed that reveal that the anti-cancer effects were associated with the downregulation of the expression of VEGF, CYCLIN-D1, and STAT-3 genes and upregulation of the apoptotic Caspase-9 gene. The group of mice that received CP combination therapy (with and without gold nanoparticles) showed a significant reduction in the size of tumor when compared to the Pacli alone treatment and control groups. Conclusions: Together, the results suggest that the delivery of gold conjugated Au-CP formulations may help in modulating the outcomes of chemotherapy. The present study is well supported with observations from cell-based assays, molecular and histopathological analyses. 相似文献
94.
95.
Starch-g-poly(methyl acrylate) (S-g-PMA), containing 40-65% PMA, was prepared with ceric ammonium nitrate (CAN) initiation in a 2-gallon reactor. CAN initiator was added either in one portion or portionwise. Graft copolymers were characterized with respect to % acetone-extractable polymer (largely PMA homopolymer), PMA content of the graft copolymer, and Mw of PMA grafts. Normal cornstarch as well as waxy and high amylose cornstarches were used in the grafting reaction. Conversions of monomer to polymer were nearly quantitative. Continuous plastic ribbons for tensile testing were prepared by extrusion processing. Tensile properties varied with the method used for CAN addition (i. e., single portion vs. portion-wise) and depended upon the particular starch variety used in the graft polymerization reaction. Since water acts as a plasticizer for starch, samples extruded at high moisture content exhibit higher % elongation (%E) values than the same polymers extruded at low moisture. Values for %E also increase with higher percentages of PMA in the graft copolymer. 相似文献
96.
This paper presents a study of the behaviour and design of concrete filled high strength steel fabricated box columns for use in tall buildings. The many advantages that can be attributed to the use of high strength steel in concrete filled steel box column constructions are presented and discussed. The paper deals with short composite columns and presents guidelines for plate slenderness and overall column slenderness to eliminate local and overall buckling. A proposed design model is developed to calculate the strength of short columns in bending and compression. A method for constructing the strength interaction diagram is presented. Furthermore, to study the ductility of this form of column construction a cross-sectional analysis computer program was developed to consider the moment-thrust-curvature response of such members. This has been undertaken using mild structural steel and high strength steel. The study also shows that, by the use of the method considered, savings can be made in the base column design of a tall building with a negligible penalty in ductility. Finally, recommendations are given for further research into this new method of column construction, which focuses on future experimental work. 相似文献
97.
D. B. Wankhede B. B. Gunjal R. A. Sawate H. B. Patil M. B. Bhosale A. T. Gahilod S. G. Walde 《Starch - St?rke》1989,41(5):167-171
Isolation and some of the important physicochemical properties of starch from rajgeera grains have been investigated. The yield of starch was about 61.2%, on whole grain basis. The results on physicochemical properties revealed that it exhibited moderate swelling and higher solubility (55.5%) in water, as compared to other millet starches. An extensive solubility in dimethylsulphoxid (72.5%) of the starch indicated easy penetration of solvent in a granular matrix, may be due to labile and heterogenous bonding forces within the granules. Brabender viscoamylographic data on pasting characteristics revealed that it yielded low viscosity (448 B. U.) at concentration of 10% (w/v) and showed very little tendency to retrograde during cooling of the starch paste. The amylopectin content was 88.5% indicating the starch of rajgeera is probably waxy in nature. Amylolytic digestibility of native and gelatinized starch of rajgeera by human salivary α-amylase and glucoamylase was investigated. 相似文献
98.
Patil Y. S. Salunkhe P. H. Navale Y. H. Patil V. B. Ubale V. P. Ghanwat A. A. 《Polymer Bulletin》2020,77(5):2205-2226
Polymer Bulletin - 2,5-Bis(4-(2-aminothiazole) phenyl)-3 and 4-diphenyltetraphenyl thiophene (TPTPThDA) are fine processed in three steps. A series of polyazomethines containing... 相似文献
99.
100.
Mingxuan Lu Prabhakar V. Gulgunje Pedro J. Arias-Monje Jeffrey Luo Jyotsna Ramachandran Yudhisthira Sahoo Sandip Agarwal Satish Kumar 《Polymer Engineering and Science》2020,60(9):2143-2151
Bi-component, polyacrylonitrile (PAN)/carbon nanotube (CNT) fibers were processed, at different core-sheath area ratios, by gel spinning. A percolated CNT network at 10 wt% CNT in the sheath enhanced electrical conductivity as compared to the neat PAN fiber, while PAN polymer in the core contributed to the good mechanical properties. Fibers with relatively thin sheath allowed overall CNT loading as low as 3.7 wt% to be made with good electrical conductivity, and PAN stabilization by Joule heating was demonstrated. Such fibers with combined good mechanical properties and electrical conductivity can also potentially be used for electrical heating of fabrics, for making smart textiles, and for electromagnetic interference shielding. 相似文献