全文获取类型
收费全文 | 3330篇 |
免费 | 73篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 107篇 |
化学工业 | 619篇 |
金属工艺 | 114篇 |
机械仪表 | 43篇 |
建筑科学 | 55篇 |
能源动力 | 80篇 |
轻工业 | 255篇 |
水利工程 | 6篇 |
石油天然气 | 4篇 |
无线电 | 364篇 |
一般工业技术 | 591篇 |
冶金工业 | 920篇 |
原子能技术 | 91篇 |
自动化技术 | 161篇 |
出版年
2023年 | 10篇 |
2022年 | 19篇 |
2021年 | 55篇 |
2020年 | 14篇 |
2019年 | 26篇 |
2018年 | 46篇 |
2017年 | 44篇 |
2016年 | 55篇 |
2015年 | 35篇 |
2014年 | 63篇 |
2013年 | 107篇 |
2012年 | 96篇 |
2011年 | 133篇 |
2010年 | 85篇 |
2009年 | 117篇 |
2008年 | 120篇 |
2007年 | 115篇 |
2006年 | 101篇 |
2005年 | 98篇 |
2004年 | 99篇 |
2003年 | 92篇 |
2002年 | 91篇 |
2001年 | 61篇 |
2000年 | 57篇 |
1999年 | 64篇 |
1998年 | 378篇 |
1997年 | 214篇 |
1996年 | 150篇 |
1995年 | 93篇 |
1994年 | 122篇 |
1993年 | 95篇 |
1992年 | 41篇 |
1991年 | 44篇 |
1990年 | 50篇 |
1989年 | 42篇 |
1988年 | 40篇 |
1987年 | 35篇 |
1986年 | 34篇 |
1985年 | 40篇 |
1984年 | 15篇 |
1983年 | 20篇 |
1982年 | 24篇 |
1981年 | 14篇 |
1980年 | 15篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 14篇 |
1976年 | 43篇 |
1975年 | 13篇 |
1972年 | 9篇 |
排序方式: 共有3410条查询结果,搜索用时 15 毫秒
71.
Takashi Hayashi Makoto Mihoya Iwao Yamai Hajime Saito Shin-Ichi Hirano 《Journal of Materials Science》1987,22(4):1305-1309
Needle-like or wool-like Al2O3 whiskers can be grown on a substrate by the hydrolysis of aluminium fluoride vapour. Effects of the growth conditions on the morphology of the crystals and growth processes of the whisker were investigated, and the optimum growth condition of whiskers was examined. Adequate vapour pressure conditions of the reactant gases for the growth of the wool-like whisker were found to be
. Aluminium oxyfluoride was assumed to be the most probable intermediate species for the growth of Al2O3 whiskers. A variety of crystal morphologies are also shown and described with respect to the experimental conditions. 相似文献
72.
73.
Tomohito Kameda Kazuya Horikoshi Shogo Kumagai Yuko Saito Toshiaki Yoshioka 《中国化学工程学报》2021,28(12):2993-3001
In this paper, we propose that the urinary toxins from the wastewater be adsorbed on an adsorbent such as spherical activated carbon and the latter be regenerated by subjecting it to high temperatures to recycle activated carbon and also to recycle the water used in dialysis. We studied the adsorption of artificial waste dialysate, which is a mixed solution of urea, creatinine, and uric acid, and the separate solutions for each of these and found that their extents of adsorption onto the spherical activated carbon material were nearly identical. The amount of adsorption was approximately 1.4 mg·g-1 for urea, 18 mg·g-1 for creatinine, and 20 mg·g-1 for uric acid. The urea, creatinine, and uric acid adsorbed onto the spherical activated carbon decomposed on heat treatment at 500℃, and the adsorption capacity of the spherical activated carbon was regenerated. Our study successfully demonstrated that the spherical activated carbon can be recycled in the waste dialysate treatment process. 相似文献
74.
Masashi Ishikawa Masae Iwasaki Hailin Zhao Junichi Saito Cong Hu Qizhe Sun Atsuhiro Sakamoto Daqing Ma 《International journal of molecular sciences》2021,22(9)
Inhalational anesthetics was previously reported to suppress glioma cell malignancy but underlying mechanisms remain unclear. The present study aims to investigate the effects of sevoflurane and desflurane on glioma cell malignancy changes via microRNA (miRNA) modulation. The cultured H4 cells were exposed to 3.6% sevoflurane or 10.3% desflurane for 2 h. The miR-138, -210 and -335 expression were determined with qRT-PCR. Cell proliferation and migration were assessed with wound healing assay, Ki67 staining and cell count kit 8 (CCK8) assay with/without miR-138/-210/-335 inhibitor transfections. The miRNA downstream proteins, hypoxia inducible factor-1α (HIF-1α) and matrix metalloproteinase 9 (MMP9), were also determined with immunofluorescent staining. Sevoflurane and desflurane exposure to glioma cells inhibited their proliferation and migration. Sevoflurane exposure increased miR-210 expression whereas desflurane exposure upregulated both miR-138 and miR-335 expressions. The administration of inhibitor of miR-138, -210 or -335 inhibited the suppressing effects of sevoflurane or desflurane on cell proliferation and migration, in line with the HIF-1α and MMP9 expression changes. These data indicated that inhalational anesthetics, sevoflurane and desflurane, inhibited glioma cell malignancy via miRNAs upregulation and their downstream effectors, HIF-1α and MMP9, downregulation. The implication of the current study warrants further study. 相似文献
75.
J. I. Zhao K. Saito T. Kondo H. Narahara S. Igarashi T. Sasaki Lei Zhang 《International Journal of Machine Tools and Manufacture》1995,35(12):1683-1692
This paper presents original research results of automatic polishing on curved surfaces of aluminium alloy moulds at constant pressure. The automatic polishing of aluminium alloy material is achieved. A parameter S is defined, which can express the comprehensive influential factors in the automatic polishing process and give a relationship among the polishing quality and the various machining variables. Based on this, a new method for comprehensive control of polishing quality is suggested. 相似文献
76.
K.Fujiyama T.Fujiwara Y.Nakatani K.Saito A.Sakuma Y.Akikuni S.Hayashi S.Matsumoto 《金属学报(英文版)》2004,17(4):338-344
Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic microstructural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants. 相似文献
77.
Humidity Sensor Characteristics of Woodceramics 总被引:9,自引:0,他引:9
Kiyokazu Kasai Kiyotaka Shibata Koji Saito Toshihiro Okabe 《Journal of Porous Materials》1997,4(4):277-280
The humidity sensor characteristics of Woodceramics were investigated. The Woodceramics used in this experiment were prepared at 650–900°C. The size of specimens selected was 1 × 1 × 10 mm . One was used as-cut and the other was polished. Above 700°C, the resistance of the specimen was below 50 and the decrease of resistance with increasing relative humidity was small. The specimen prepared at 650°C had a resistance of about 1 k. The resistance of as-cut specimens decreased with increase in relative humidity, but that of the polished specimen did not change significantly. The difference between as-cut and polished samples was explained by the differences in surface micro-structure. 相似文献
78.
Toshio Kimura Toru Takahashi Toshihiko Tani Yasuyoshi Saito 《Journal of the American Ceramic Society》2004,87(8):1424-1429
Bi0.5 Na0.5 TiO3 (BNT) and 0.94Bi0.5 Na0.5 TiO3 ·0.06BaTiO3 (BNT–BT) bulk ceramics with extensive 〈100〉 texture were prepared by the reactive-templated grain growth method, using platelike Bi4 Ti3 O12 (BIT) particles as templates for BNT. Calcined compacts were composed of matrix grains with random orientation and 〈100〉-oriented grains transformed from aligned BIT particles, and the texture developed by the growth of oriented grains during sintering. Ceramics with extensive texture were obtained by using the starting mixture containing the maximum concentration of platelike BIT to form the maximum volume fraction of oriented grains. 相似文献
79.
80.
Keizo Uematsu Jin-Young Kim Masayori Miyashita Nozomu Uchida Katsuichi Saito 《Journal of the American Ceramic Society》1990,73(8):2555-2557
The internal structure of spray-dried alumina granules was characterized by optical microscopy by immersing them in a liquid having a refractive index close to that of alumina. This method provides a unique technique for the detailed analysis of the internal structure of spray-dried granules. 相似文献