全文获取类型
收费全文 | 1181篇 |
免费 | 32篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 70篇 |
综合类 | 7篇 |
化学工业 | 217篇 |
金属工艺 | 30篇 |
机械仪表 | 30篇 |
建筑科学 | 23篇 |
矿业工程 | 4篇 |
能源动力 | 35篇 |
轻工业 | 56篇 |
水利工程 | 13篇 |
石油天然气 | 12篇 |
无线电 | 142篇 |
一般工业技术 | 133篇 |
冶金工业 | 324篇 |
原子能技术 | 33篇 |
自动化技术 | 92篇 |
出版年
2023年 | 8篇 |
2022年 | 26篇 |
2021年 | 22篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 23篇 |
2017年 | 25篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 26篇 |
2013年 | 63篇 |
2012年 | 42篇 |
2011年 | 55篇 |
2010年 | 30篇 |
2009年 | 45篇 |
2008年 | 38篇 |
2007年 | 50篇 |
2006年 | 37篇 |
2005年 | 26篇 |
2004年 | 40篇 |
2003年 | 30篇 |
2002年 | 17篇 |
2001年 | 19篇 |
2000年 | 23篇 |
1999年 | 24篇 |
1998年 | 116篇 |
1997年 | 63篇 |
1996年 | 50篇 |
1995年 | 31篇 |
1994年 | 31篇 |
1993年 | 31篇 |
1992年 | 22篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1974年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
排序方式: 共有1221条查询结果,搜索用时 15 毫秒
121.
The preceding paper[5] demonstrated that nitrogen dissolves in silicate melts either as a free ion or complex anion, being incorporated into silicate
networks. In the present study, the influence of CaF2 addition to CaO-SiO2 melts on the nitrogen solubility was investigated along the liquidus at 1573 K and within the liquidus at 1723 K at constant
CaF2 levels. In the latter case, as the SiO2 content increases from CaO saturation, the total nitrogen content decreases to reach the minimum and then starts to increase
up to the SiO2 saturation. This is in accord with the abovementioned mechanism of nitrogen dissolution, which is supported by the changing
behavior of free and incorporated nitrogen contents with the slag composition. The role of CaF2 is complicated through the formation of fluorosilicates. The CaF2 seems not to function simply as a diluent but to enhance the dissolution of nitrogen by releasing oxygen from silicate networks,
promoting the formation of free nitride ions.
Formerly Graduate Student, Department of Metallurgy, The University of Tokyo. 相似文献
122.
H Sano H Ishii A Yeadon DS Backman JA Brunet HK Uhthoff 《Canadian Metallurgical Quarterly》1997,15(5):719-726
The purpose of this investigation was to determine the relationship between the degree of degeneration at the supraspinatus insertion, the tensile strength, and the site of failure of this tendon. Thirty-three fresh cadaveric shoulders (average age: 62 years; range: 39-83 years) were examined. A tensile load to failure was applied at a constant crosshead speed of 25.4 mm/min to a 10 mm wide strip of the supraspinatus tendon that remained attached to the bone. Preexisting degenerative changes at the insertion were assessed and scored histologically and compared with the ultimate tensile stress. Twenty tendons failed at the insertion (the insertion group), and 11 failed in the midsubstance (the midsubstance group). The histologic score of degeneration for the insertion group was significantly higher than that for the midsubstance group (p = 0.0026). There was a negative correlation between the ultimate tensile stress at the insertion and the degeneration score for the insertion group (r = -0.60; p = 0.013). Histologic observations revealed that disruptions of tendon fibers were located mostly in the articular half of the tendon and that they enlarged during mechanical testing in 90% of the specimens of the insertion group. It seems that degenerative changes at the supraspinatus insertion reduce the tensile strength of the tendon and constitute a primary pathogenetic factor of rotator cuff tear. 相似文献
123.
This paper describes a novel dynamic flip-flop (FF) circuit that can operate 30% faster than conventional clocked inverter-type FFs. A new wideband clock buffer is introduced to cover the FF operation range. An 8- to 24-Gb/s decision circuit and a 9- to 26-GHz 1/2 frequency divider were developed utilizing production-level 0.2-μm GaAs MESFET technology 相似文献
124.
Pornthep Chivavibul Makoto Watanabe Seiji Kuroda Jin Kawakita Masayuki Komatsu Kazuto Sato Junya Kitamura 《Journal of Thermal Spray Technology》2011,20(5):1098-1109
Warm spray (WS) process, which can control the temperature of a combustion gas jet used to propel powder, has been successfully
applied to deposit WC-Co coatings. Detrimental reactions resulting from dissolution of WC into Co binder and decarburization
were suppressed effectively by keeping the WC-Co particles’ temperature below the m.p. of the binder phase. In this study,
three nano-structured WC-12Co powders with different particle strengths were prepared by changing the sintering conditions
of spray-dried powder and were deposited by WS. The deposition efficiency and porosity of the coatings decreased with increasing
the particle strength. The coating deposited from the powder with very low particle strength showed significant phase changes,
while those deposited from the higher particle strengths showed almost no change. Particle Image Velocimetry revealed significant
disintegration of the weakest powder, which explains the changes observed. The hardness and wear properties of the former
coating, therefore, were inferior to the other two. 相似文献
125.
In view of the importance of tramp element contamination of steel products through a large volume of scrap consumption in the near future, the thermodynamic behaviour of Sb, As, Sn and Cu in CaO—CaF2 melts under reducing conditions was studied by examining the dependences of distribution of each element between Cu, Ag or Sn alloys and CaO—CaF2 melts on the CaO activity, oxygen partial pressure and temperature around 1 500°C. As a result, the reaction products on treatment by Ca compounds were demonstrated to be Ca3Sb2, Ca3As2, Ca2Sn and CaCu. Experimentally obtained distributions were extrapolated to lower oxygen partial pressures less than 10?18 atm to estimate the feasibility of removing those tramp elements from molten iron. It is thermodynamically indicated that if the prevailing oxygen partial pressure of the environment is below 10?23 atm, these impurities, except Cu, would be substantially removed from molten steel. 相似文献
126.
Ishii K. Nosaka H. Nakajima H. Kurishima K. Ida M. Watanabe N. Yamane Y. Sano E. Enoki T. 《Solid-State Circuits, IEEE Journal of》2002,37(9):1146-1151
Using InP-InGaAs heterojunction bipolar transistor (HBT) technology, we have successfully designed and fabricated a low-power 1:16 demultiplexer (DEMUX) integrated circuit (IC) and one-chip clock and data recovery (CDR) with a 1:4 DEMUX IC for 10-Gb/s optical communications systems. The InP-InGaAs HBTs were fabricated by a nonself-aligned process for high uniformity of device characteristics and producibility. The 1:16 DEMUX IC and the one-chip CDR with the 1:4 DEMUX IC consist of approximately 1200 and 460 transistors, respectively. We have confirmed error-free operation at 10 Gb/s for all data outputs of both ICs. The 1:16 DEMUX IC and the one-chip CDR with the 1:4 DEMUX IC consume only 1 W and 950 mW, respectively. These results demonstrate the feasibility of InP-InGaAs HBTs for low power high-integration optical communication ICs. 相似文献
127.
M Satoh T Sakai I Sano K Fujikura H Koyama K Ohshima Z Itoh S Omura 《Canadian Metallurgical Quarterly》1994,271(1):574-579
Erythromycin and its derivatives are known to induce phase III-like contractions, which are similar to those induced by motilin, in the human gastrointestinal tract during the interdigestive state, but few detailed in vitro studies have been reported. We evaluated EM574, an erythromycin derivative, as a motilin receptor agonist in the human gastric antrum in vitro, using contraction studies of muscle strips and isolated myocytes, receptor binding assay and tissue section autoradiography. EM574 stimulated contractions of muscle strips in a concentration-dependent manner (10(-7)-10(-5) M), and this contractile effect was unaffected by pretreatment with atropine or tetrodotoxin. Isolated myocytes contracted in response to EM574 with a peak shortening at 10(-7) M, which was comparable to the response to motilin. EM574 displaced specifically 125I-motilin bound to smooth muscle homogenates with a Kd value of 7.8 x 10(-9) M, compared with 4.5 x 10(-9) M for motilin. Film autoradiograms showed that 125I-motilin-binding sites were localized in the muscle layers, and that the labeling disappeared in the presence of a 1000 times molar concentration of EM574. We conclude that EM574 directly stimulates smooth muscle cell contraction by acting on motilin receptors in the human gastric antrum in vitro. 相似文献
128.
M Sano Y Takagi M Kimura K Akagashi S Hisasue H Adachi J Wakabayashi 《Canadian Metallurgical Quarterly》1998,89(11):903-906
A 67-year-old man visited our hospital with the chief complaint of painless swelling of the left scrotal content. An elastic hard mass was palpable in the left scrotum. Resection of the tumor, including the left scrotal skin, was performed. The tumor originated from the scrotal wall and did not communicate with the testis, the epididymis or spermatic cord. Histologically, the tumor was diagnosed as a malignant mesenchymoma composed of liposarcoma, chondrosacoma and osteosarcoma. Malignant mesenchymoma is very rare, especially in the scrotum. Our case that originated from the scrotal wall is the first one reported in Japan. 相似文献
129.
This paper overviews the fundamental problems encountered in device modeling and simulations of sub-10 nm Si metal-oxide-semiconductor field-effect-transistors (MOSFETs). We focus on the two fundamental problems: the quantum effects and the effects associated with the long-range Coulomb potential. It is pointed out that these problems are profoundly related to the basic principles of device physics and even pose a question on the validity of the basic transport equation which the present device simulations are based on. We also review various approaches and methods taken to tackle those problems 相似文献
130.
SM Albert M Sano K Bell C Merchant S Small Y Stern 《Canadian Metallurgical Quarterly》1998,38(6):704-714
People with Alzheimer's disease living in a defined community in New York City were identified and assessed on two occasions to determine the number of hours of activities of daily living (ADL) care they received. Nearly half received all care hours from informal sources; however, a quarter received all ADL care hours from formal sources. The mean number of daily ADL hours in the sample was 9.7, of which 4.2 came from formal sources. This reflects the extensive use of Medicaid-based home care services in New York City. As dementia worsened, substitution of formal for informal care was rare, but formal care assumed a greater proportion of total care hours. 相似文献