全文获取类型
收费全文 | 6884篇 |
免费 | 99篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 376篇 |
综合类 | 3篇 |
化学工业 | 1241篇 |
金属工艺 | 206篇 |
机械仪表 | 162篇 |
建筑科学 | 112篇 |
能源动力 | 174篇 |
轻工业 | 476篇 |
水利工程 | 34篇 |
石油天然气 | 6篇 |
无线电 | 637篇 |
一般工业技术 | 1208篇 |
冶金工业 | 1795篇 |
原子能技术 | 136篇 |
自动化技术 | 435篇 |
出版年
2023年 | 28篇 |
2022年 | 64篇 |
2021年 | 111篇 |
2020年 | 50篇 |
2019年 | 56篇 |
2018年 | 71篇 |
2017年 | 68篇 |
2016年 | 77篇 |
2015年 | 76篇 |
2014年 | 96篇 |
2013年 | 235篇 |
2012年 | 205篇 |
2011年 | 286篇 |
2010年 | 197篇 |
2009年 | 216篇 |
2008年 | 230篇 |
2007年 | 233篇 |
2006年 | 222篇 |
2005年 | 196篇 |
2004年 | 186篇 |
2003年 | 189篇 |
2002年 | 186篇 |
2001年 | 161篇 |
2000年 | 141篇 |
1999年 | 167篇 |
1998年 | 671篇 |
1997年 | 431篇 |
1996年 | 306篇 |
1995年 | 219篇 |
1994年 | 220篇 |
1993年 | 176篇 |
1992年 | 99篇 |
1991年 | 105篇 |
1990年 | 94篇 |
1989年 | 84篇 |
1988年 | 75篇 |
1987年 | 64篇 |
1986年 | 75篇 |
1985年 | 85篇 |
1984年 | 58篇 |
1983年 | 60篇 |
1982年 | 49篇 |
1981年 | 56篇 |
1980年 | 57篇 |
1979年 | 33篇 |
1978年 | 28篇 |
1977年 | 54篇 |
1976年 | 56篇 |
1975年 | 31篇 |
1973年 | 27篇 |
排序方式: 共有7001条查询结果,搜索用时 0 毫秒
961.
H Niiyama K Yamaguchi S Shimizu K Yokohata K Chijiiwa H Yonemasu M Tanaka 《Canadian Metallurgical Quarterly》1998,10(8):703-707
We report an unusual case of laryngomucocele occurring after subtotal laryngectomy. Laryngoceles generally have a congenital origin in a long-preexisting saccule, and their association with laryngeal carcinoma is well known. Laryngocele is usually favored by the increase of intraglottic pressure caused by the laryngeal carcinoma. However, an iatrogenic secondary laryngomucocele occurring after a surgical procedure is uncommon. We report in detail the physiopathologic conditions leading to the creation of this lesion. 相似文献
962.
963.
The authors propose a new ARQ scheme suitable for image transmission over radio channels. The proposed scheme detects only serious degradation and so attains higher throughput performance than the conventional ARQ scheme 相似文献
964.
965.
T Tanaka T Morimoto Y Kinouchi T Iritani Y Monden 《Canadian Metallurgical Quarterly》1995,195(5):255-264
With hyperthermia for treatment of superficial tumors in mind, a prototype applicator with two electrodes arranged concentrically on a disk was designed for efficient local heating, and a basic heating test was carried out. Frequencies as low as 200 kHz were used in order to simplify the configuration of the power device. The applicator consists of two electrodes, a circular inner electrode and another looped outer electrode, arranged concentrically. Water was passed through the applicator as a cooling mechanism; it was placed in direct contact with the target tissue to be heated and then charged with electricity. In the heating test using a phantom, oval hot spots were noted below the inner electrode. Using cooling water at 3 degrees C and 8.2 W, an isothermal line of 45 degrees C was located at a 5-mm radius circle around the central axis with 9 mm depth. A similar temperature distribution map was obtained in heating tests on the thigh muscle of a mongrel adult dog. The temperature distribution maps obtained from these tests corresponded closely with the results of theoretical analysis carried out according to the finite-element method. Since a comparatively low frequency was employed for this applicator the power device was simplified, which made adequate heating possible with low electric power. The temperature distribution map indicated that efficient local heating of superficial tumors could be achieved. 相似文献
966.
Yuzuru Tanaka 《New Generation Computing》1984,2(3):241-260
Everlasting demands for solutions to ever growing computation problems and demands for efficient means to manage and utilize sophisticated information have caused an increase in the amount of data necessary to handle a job, while drastic reduction in CPU prices is encouraging massive parallel architectures for gigantic data processing. These trends are increasing the importance of a large shared buffer memory with 103~104 simultaneously accessible ports. This paper proposes a multiport page buffer architecture that allows 103~104 concurrent accesses and causes no access conflict nor suspension. It consists of a set of memory banks and multistaged switching networks with controllers that control each row of the networks. Consecutive words in each page are stored orthogonally across banks. Memory interleaving may be applied to improve access rate in consecutive retrievals. When used as a disk cache memory, it decreases the number of disk accesses and increases both the page transfer rate and the maximum number of concurrent page accesses. 相似文献
967.
The electric field distribution in an automobile body must be known when developing an antenna system mounted inside the car body for mobile communication. A microwave simulation experiment was carried out in an electromagnetic anechoic chamber using 4 GHz band signals and a miniaturized automobile. The automobile model used in this simulation experiment was about 1/15 of the size of the actual automobile under consideration. A simpler box-type model with large apertures was also studied. The internal electric field distribution measured in the box model was estimated to be a combination of the resonant TEPmn modes excited in the box. which acted as a resonant cavity. The spatial and frequency dependence of the internal automobile's electromagnetic field for each model is plotted for the frequency range 3-5 GHz 相似文献
968.
Yokokawa S. Ueki Y. Tanaka H. Doi H. Ueda K. Taniguchi N. 《Energy Conversion, IEEE Transaction on》1988,3(3):479-486
A digital control system using the optimal control has been developed for a thermal power generator. In order to increase the generator control performance for improving the power system stability, this system supplies the excitation system directly with control signals and provides the governor system with control signals and supplemental control signals for a conventional governor. The system utilizes adaptive control for changes in generator nonlinear characteristics, as well as in power system characteristics. The principles and application of this system are described and results of simulation tests using a 1000 MVA thermal power plant model on a high-reliability AC/DC electric power system simulator are presented. The results verify the performance of this system, as well as the applicability of the system to actual plants 相似文献
969.
Y Toyooka SS Tanaka O Hirota S Tanaka N Takagi K Yamanouchi H Tojo C Tachi 《Canadian Metallurgical Quarterly》1998,42(8):1143-1151
With the aim of identifying the gene(s) located downstream from SRY, we transfected an ES cell line with XX karyotype, TMA-18, with a Sry DNA construct and established cell lines, TS18-1 and TS18-2, where the transfected Sry was expressed in the functional linear mRNA form. Among the five potential SRY-target genes examined, i.e., MIS, SF1, P450arom, Sox9 and WT1, only the expression of WT1 was induced de novo by the unscheduled expression of Sry in the transfected cell lines. No clear indication of Sry-induced enhancement of Sox9 expression was obtained in the present series of experiments. Function of a yet unidentified gene(s) located on the Y chromosome might be needed for the up-regulation of Sox 9 expression which takes place during the development of male gonads. Quantitative RT-PCR analysis of the patterns of WT1 expression in developing fetal gonads revealed that although both male and female fetal gonads express WT1, male gonads invariably expressed WT1 mRNA at higher levels than female ones after the Sry expression. Immunohistochemical analysis of the male fetal gonads between 10.5 and 13.5 dpc demonstrated the presence of strong WT1 immunoreactivity in Sertoli cells of the primordial testes. Suggestions were made in the past indicating that both SF1 and WT1 proteins might be active in a common pathway upstream from Sry. Our results showed that WT1 is located downstream, rather than upstream from Sry and behaves independently from SF1. Analysis using an appropriate in vitro system will be essential to understand the molecular mechanisms of SRY action within cells. 相似文献
970.
T Tanaka M Fujita I Nakae S Tamaki K Hasegawa Y Kihara R Nohara S Sasayama 《Canadian Metallurgical Quarterly》1998,32(7):1982-1986
OBJECTIVES: The purpose of this study was to evaluate whether a serotonin blocker, sarpogrelate, improves exercise capacity as a result of vasodilation of coronary collateral channels in patients with effort angina. BACKGROUND: Serotonin has been reported to decrease coronary collateral blood flow by collateral vasoconstriction in a canine model, suggesting that platelet activation in feeding coronary arteries of the collateral network has the potential to cause collateral vasoconstriction. METHODS: The subjects consisted of 22 patients with effort angina and reproducible ischemic threshold (group A, 11 patients with thrombolysis in myocardial infarction (TIMI) grade 2 or 3 flow of the ischemia-related coronary artery and Rentrop's collateral index 0 or 1; group B, 11 patients with TIMI grade 0 or 1 flow and Rentrop's collateral index 2 or 3). We repeated the symptom-limited treadmill exercise test using the Balke-Ware protocol and exercise tetrofosmin myocardial perfusion scintigraphy with and without pretreatment with 200 mg orally administered sarpogrelate. Each exercise test was performed at 9:00 a.m. on different days. The order of tests with and without sarpogrelate was randomized. RESULTS: In group A, sarpogrelate increased neither exercise time at 0.1 mV ST depression nor double product at 0.1 mV ST depression. In contrast, in group B sarpogrelate increased the exercise duration at 0.1 mV ST depression from 181+/-112 (SD) to 248+/-131 s (p < 0.05) and also increased the double product at 0.1 mV ST depression by 21% (p < 0.01). The severity score using myocardial perfusion scintigraphy at the same workload was significantly (p < 0.01) decreased by 37% in group B, but not in group A (11%), due to the sarpogrelate treatment. CONCLUSIONS: Sarpogrelate augments flow reserve of the collateral circulation and improves exercise capacity in anginal patients with well-developed collaterals. These findings indicate that a serotonin blocker, sarpogrelate, is useful not only as an antiplatelet drugs, but as an antianginal drug. 相似文献