全文获取类型
收费全文 | 858篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 38篇 |
化学工业 | 169篇 |
金属工艺 | 13篇 |
机械仪表 | 26篇 |
建筑科学 | 32篇 |
能源动力 | 36篇 |
轻工业 | 95篇 |
水利工程 | 3篇 |
无线电 | 62篇 |
一般工业技术 | 135篇 |
冶金工业 | 162篇 |
原子能技术 | 30篇 |
自动化技术 | 67篇 |
出版年
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 36篇 |
2012年 | 27篇 |
2011年 | 51篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 39篇 |
2007年 | 26篇 |
2006年 | 20篇 |
2005年 | 27篇 |
2004年 | 21篇 |
2003年 | 32篇 |
2002年 | 16篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 23篇 |
1998年 | 59篇 |
1997年 | 40篇 |
1996年 | 24篇 |
1995年 | 14篇 |
1994年 | 22篇 |
1993年 | 22篇 |
1992年 | 10篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 10篇 |
1983年 | 19篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1973年 | 4篇 |
1971年 | 3篇 |
排序方式: 共有868条查询结果,搜索用时 0 毫秒
91.
Mizue Munekata Seiichi Kimura Hiroaki Kurishima Jinsuke Tanaka Sohei Yamamoto Hiroyuki Yoshikawa Kazuyoshi Matsuzaki Hideki Ohba 《热科学学报(英文版)》2008,17(1):56-60
Recently, development of high technology has been required for the formation of thin uniform film in manufacturing processes of semiconductor as the semiconductor instruments become more sophisticated. Spin coating is usually used for spreading photoresist on a wafer surface. However, since rotating speed of the disk is very high in spin coating, the dropped photoresist scarers outward and reattaches on the film surface. A catch cup is set up outside the wafer in spin coating, and scattered photoresist mist is removed from the wafer edge by the exhaust flow generated at the gap between the wafer edge and the catch cup. In the dry process of a spin coating, it is a serious concern that the film thickness increases near the wafer edge in the case of low rotating speed. The purpose of this study is to make clear the effect of the catch cup geometry on the 3D boundary layer flow over the wafer surface and the drying rate of liquid film. 相似文献
92.
A neutronic analysis of the laser-driven inertial-confinement fusion reactor SENRI-I is presented. Three-dimensional Monte Carlo calculations were performed to examine the effects of laser beam ports on the flux distribution, tritium breeding ratio, thermal energy deposition in the blanket, and radiation streaming. A Monte Carlo code was also used for the time-dependent radiation-damage analysis accounting for the time of the flight spread of neutrons and the results are compared to the analysis for the HIBALL design. Induced radioactivity was estimated, based on the one-dimensional transport calculation and depletion analysis. The calculated results reveal the advantages of the SENRI-I design with a thick Li layer compared to other reactor systems employing a dry-wall scheme. 相似文献
93.
The dorsal raphe nucleus (DRN) is an important nucleus in pain modulation. It has abundant 5-HT neurons and many other neurotransmitter and/or neuromodulator containing neurons. Its vast fiber connections to other parts of the central nervous system provide a morphological basis for its pain modulating function. Its descending projections, via the nucleus raphe magnus or directly, modulate the responses caused by noxious stimulation of the spinal dorsal horn neurons. In ascending projections, it directly modulates the responses of pain sensitive neurons in the thalamus. It can also be involved in analgesia effects induced by the arcuate nucleus of the hypothalamus. Neurophysiologic and neuropharmacologic results suggest that 5-HT neurons and ENKergic neurons in the DRN are pain inhibitory, and GABA neurons are the opposite. The studies of the intrinsic synapses between ENKergic neurons, GABAergic neurons, and 5-HT neurons within the DRN throw light on their relations in pain modulation functions, and further explain their functions in pain mediation. 相似文献
94.
H Tada K Asazuma E Ohya T Hayashi T Nakai T Nakayama T Ueda 《Canadian Metallurgical Quarterly》1998,97(2):220-221
This article describes a procedure for making an interocclusal record for a remount procedure after tryin of the castings. This method can also be used for the initial mounting by substituting autopolymerizing acrylic resin copings for the metal castings. 相似文献
95.
Journal of Fusion Energy - 相似文献
96.
The molecular chaperone ClpX of Escherichia coli plays two distinct functions for bacteriophage Mu DNA replication by transposition. As specificity component of a chaperone-linked protease, it recognizes the Mu immunity repressor for degradation by the peptidase component ClpP, thus derepressing Mu transposition functions. After strand exchange has been promoted by MuA transposase, ClpX alone can alter the conformation of the transpososome (the complex of MuA with Mu ends), and the remodeled MuA promotes transition to replisome assembly. Although ClpXP can degrade MuA, the presence of both ClpP and ClpX in the reconstituted transposition system did not destroy MuA essential for initiation of DNA replication by specific host replication enzymes. Levels of ClpXP needed to overcome inhibition by the repressor did not prevent MuA from promoting strand transfer, and ClpP stimulated alteration of the transpososome by ClpX. Apparently intact MuA was still present in the resulting transpososome, promoting initiation of Mu DNA replication by specific replication enzymes. The results indicate that ClpXP can discriminate repressor and MuA in the transpososome as substrates of the protease or the molecular chaperone alone, degrading repressor while remodeling MuA for its next critical function. 相似文献
97.
A Higuchi H Nakai M Miyazato M Izumitani S Shishido T Kawamura 《Canadian Metallurgical Quarterly》1996,87(10):1145-1150
BACKGROUND: It is difficult to diagnose intermittent hydronephrosis and to decide the indication of surgical intervention. We investigated 23 cases of intermittent hydronephrosis. METHODS: From 1978 to 1995, a total of 23 patients were diagnosed as intermittent hydronephrosis in our institution. We inspected their clinical features and treatment which had been performed to them. RESULTS: Our study comprised 21 boys and 2 girls, whose mean age was 6 year old. Their chief complaint was intermittent flank pain (left: 21, right: 1, bilateral: 1) accompanied with gross hematuria (30%) and vomiting (39%). When they were asymptomatic, an excretory urogram revealed only mild pelvic dilatation without calyceal distension and kinking of ureteropelvic junction. Split renal function study by RI showed no difference between the affected side and the normal side except one case. When pelvic or calyceal enlargement was confirmed on ultrasonography while they were symptomatic, surgery was indicated. Surgery was performed in 17 cases (74%) including dismembered pyeloplasty in 14 cases, resection of aberrant vessel in 1, relocation of lower pole renal vessel in 1 and nephrectomy in 1. In surgical and histological view points, intrinsic stenosis was seen in 10 cases, extrinsic obstruction caused by aberrant vessels was seen in 4 and ureteral polyp was seen in 3 (bilateral polyp in 1 case). CONCLUSION: They had no more symptoms after operation. Of 23 among followed up cases without surgery, we experienced 2 cases unexpectedly advancing irreversible hydronephrotic change after the last attack, 1 case of gradually progressing hydronephrotic change and 1 case of severe renal dysfunction after many attacks. Therefore intermittent hydronephrosis should be followed up carefully. 相似文献
98.
H Kuroda M Fukushima M Nakai T Katayama N Murakami 《Canadian Metallurgical Quarterly》1997,61(5):633-637
The period of free-running rhythms (tau) in rats, as measured using a running wheel, is different from that measured using an Automex. The aim of this work was to examine the effects of lesions of the intergeniculate leaflet (IGL) on the tau of these two activity rhythms. When blind rats were transferred from a cage with a running wheel to a cage without a running wheel, the tau lengthened. The tau of the wheel-running activity was associated with the number of wheel revolutions per day. A complete lesion of the IGL lengthened the tau of the wheel-running activity, and caused a reduction in the number of wheel revolutions per day in all rats. In rats housed in cages without a running wheel, locomotor activity was reduced by IGL lesions, although the tau was unaffected. When IGL-lesioned rats were transferred from a cage with a running wheel to a cage without a running wheel, no further change was observed. These results indicate that the tau is modified by the daily activity of wheel-running, but not by general locomotor activity, and that the IGL may be involved in this modification. 相似文献
99.
T Nishizawa M Furuhashi T Nagai T Nakai K Muroga 《Canadian Metallurgical Quarterly》1997,63(4):1633-1636
A molecular phylogenetic analysis of 25 isolates of fish nodaviruses, the causative agents of viral nervous necrosis of marine fish, was performed based on the nucleotide sequences (427 bases) of the coat protein gene. These fish nodaviruses were classified into four clusters: tiger puffer nervous necrosis virus, striped jack nervous necrosis virus, berfin flounder nervous necrosis virus, and red-spotted grouper nervous necrosis virus. 相似文献
100.
T Nakai N Tonouchi T Tsuchida H Mori F Sakai T Hayashi 《Canadian Metallurgical Quarterly》1997,61(9):1500-1503
The cDNA fragment coding for mung bean (Vigna radiata Wilczek) sucrose synthase was introduced into the expression vector pET-20b resulting in the construction of plasmid pEB-01. After transformation of Escherichia coli strain BL21(DE3) cells by pEB-01 and induction with isopropyl thio-beta-galactoside, high level expression of the recombinant enzyme was obtained. The enzyme had a tetrameric form that conserved the activity of sucrose synthase. Although the Km and Vmax of the recombinant enzyme acting on either UDP-glucose or fructose were very close to those of the native enzyme isolated from mung bean seedlings, the Km for sucrose was higher by a factor of 10 for the recombinant enzyme. This suggests that the recombinant sucrose synthase has a tendency to synthesize sucrose, although the native enzyme catalyzes a freely reversible reaction. 相似文献