全文获取类型
收费全文 | 639篇 |
免费 | 12篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 46篇 |
化学工业 | 69篇 |
金属工艺 | 19篇 |
机械仪表 | 18篇 |
建筑科学 | 14篇 |
能源动力 | 8篇 |
轻工业 | 32篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 43篇 |
一般工业技术 | 90篇 |
冶金工业 | 251篇 |
原子能技术 | 29篇 |
自动化技术 | 36篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 2篇 |
2019年 | 10篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 24篇 |
2012年 | 21篇 |
2011年 | 21篇 |
2010年 | 12篇 |
2009年 | 16篇 |
2008年 | 13篇 |
2007年 | 21篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 9篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 27篇 |
1998年 | 91篇 |
1997年 | 49篇 |
1996年 | 36篇 |
1995年 | 24篇 |
1994年 | 13篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 17篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 9篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1970年 | 1篇 |
排序方式: 共有657条查询结果,搜索用时 0 毫秒
41.
Akiba T Tanaka T Nagano M Mori K Hayashi Y Obata H Chiba T Ikuta Y Kamiya Y Nakama A Hosaka M Kai A 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2010,51(5):237-241
Norovirus (NV) RNA has rarely been detected in foods despite the use of highly sensitive methods such as RT-PCR and real-time RT-PCR. In the modified method (A3T method) reported previously, a bacterial culture process was introduced into the standard protocol for NV detection to remove some inhibitor(s) present in food ingredients. To confirm the efficiency of the A3T method and to examine NV contamination in bivalve molluscs, we tried to detect NV RNA in bivalve molluscs on the market and in oyster samples associated with foodborne outbreaks by using the standard method and the A3T method. NV RNAs were detected in 20 samples (18.0%) of 111 bivalve molluscs, including oysters, on the market by use of the A3T method, while only one sample (0.9%) was positive according to the standard method. NV RNA was also detected in 10 of 35 oyster samples related to foodborne outbreaks by the A3T method. Those results show that the A3T method is suitable for the detection of NV in bivalve molluscs in general laboratories. 相似文献
42.
A fluorous micellar system in water has been created to produce a large interfacial area between these media that retains substrates, effectively facilitating intermolecular Diels–Alder reactions due to repulsion effects from both media. Because LiFOS functioned not only as a surfactant but also as a supporting electrolyte, an electrochemical approach could be introduced to evaluate the rate acceleration effects. The measurement of the particle size distribution of the fluorous micelles clearly supported these evaluations. 相似文献
43.
Takuya Noguchi Toshihiro Shimada Takashi Chiba Masao Terada Tetsuya Hasegawa 《Diamond and Related Materials》2010,19(2-3):107-109
We have carried out very high temperature heat treatment at 1400–2700 °C of about 10 nm-thick amorphous carbon thin films deposited on refractory substrates MgO, Al2O3, and yttria-stabilized zirconia (YSZ) using pulsed laser deposition techniques. After the annealing, a few nanometer scale sp2 crystallization of the films and a large corrugation with a height of more than 1 μm were observed by Raman spectroscopy analysis and optical/atomic force microscopes, respectively. The corrugation is probably caused by the formation of gases at the film/substrate interface during the heat treatment. 相似文献
44.
Hara H. Sakurai T. Nagamatsu T. Seta K. Momose H. Niitsu Y. Miyakawa H. Matsuda K. Watanabe Y. Sano F. Chiba A. 《Solid-State Circuits, IEEE Journal of》1992,27(11):1579-1584
BiCMOS standard cell macros, including a 0.5-W 3-ns register file, a 0.6-W 5-ns 32-kbyte cache, a 0.2-W 3-ns table look-aside buffer (TLB), and a 0.1-W 3-ns adder, are designed with a 0.5-μm BiCMOS technology. A supply voltage of 3.3 V is used to achieve low power consumption. Several BiCMOS/CMOS circuits, such as a self-aligned threshold inverter (SATI) sense amplifier and an ECL HIT logic are used to realize high-speed operation at the low supply voltage. The performance of the BiCMOS macros is verified using a fabricated test chip 相似文献
45.
Beam-shape correction in deployable phased arrays 总被引:1,自引:0,他引:1
Yonezawa R. Konishi Y. Chiba I. Katagi T. 《Antennas and Propagation, IEEE Transactions on》1999,47(3):482-486
Deployable phased-array antennas-antennas that are receiving great attention-have a major problem in that they possess the possibility of an incomplete deployment and antenna shape distortion. These effects cause a displacement of the element antenna positions that results in deviation of the phase distribution on the antenna aperture, eventually causing antenna beam deflection. We have investigated how to correct this beam deflection by observing the phased-array antenna from certain directions. There are cases when more than one observation point is necessary to carry out the proposed method depending on the extent of the antenna shape distortion and the number of the points is consulted. This correction method makes it possible to correct the deflection of the main beam and also to determine the displacement of relative element positions 相似文献
46.
A rapid liquid flow into a tank may impinge on the free surface, making it swell partially. The returning flow branches off from the free surface and re-submerges at the border of the swollen surface. If the flow velocity along the swollen surface is high enough, gas bubbles are formed at the border and entrained by the liquid flow. The conditions necessary for gas entrainment in a simple system are examined experimentally, using water and air as working fluids. The effect of surface tension is examined by adding a surface active agent to the water. The results show that gas entrainment inception is determined by the flow pattern in the system and the product of the Froude and Weber numbers based on the local velocity at the bubble formation point. 相似文献
47.
48.
This study investigated the role of the basal forebrain cholinergic system (BFCS) in rats' performance of a visuospatial attention task. Muscimol was infused bilaterally and unilaterally into the BFCS to inhibit cholinergic projections to the cortex. Muscimol slowed responding without significantly affecting side-bias. Bilateral infusions increased accuracy for all targets, whereas unilateral infusions reduced accuracy for targets contralateral to the infusion and increased accuracy for targets ipsilateral to the infusion. After a low unilateral dose of muscimol, invalid cues impaired detection of contralateral targets and spared detection of ipsilateral targets. A high unilateral dose of muscimol impaired detection of contralateral targets independently of cueing. These results suggest that interhemispheric imbalance in cortical activity by pharmacological manipulation of the BFCS can impair the detection of lateralized visual stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
49.
A 1.7 GHz-based class-F GaAs FET amplifier is proposed. To achieve high-efficiency performance, a precisely adjustable terminating circuit constructed with lumped elements is introduced. Power-added efficiency of 68% at 1.5 W output is attained with the amplifier. 相似文献
50.
Barium titanium trioxide (BaTiO3) thin films were deposited on fused silica or silicon wafer substrate from barium dipivaloylmethanate (II) (Ba(dpm)2) and titanium tetraisopropoxide (IV) (TTIP) used as precursors in an oxygen microwave plasma. The substrates were dielectrically heated and the substrate temperatures were around 900 K during the film deposition. The deposition was performed for 15 min and the deposits were identified as BaTiO3 by means of X-ray diffraction, X-ray photoelectron spectroscopy, infrared spectroscopy, and ellipsometry. Oxygen and barium atoms and TiO and CO molecules were identified in the plasma. These species would produce higher deposition rates at lower substrate temperatures than those did in the usual thermal metalorganic chemical vapor deposition (MOCVD). The dielectric constant of the BaTiO3 thin film that was directly deposited on the silicon wafer substrate was as low as 101 order of magnitude. Because the deposit reacted with the substrate and an interdiffusional layer was formed, the platinum layer was coated on the silicon wafer substrate in order to prevent the formation of an interdiffusional layer. The dielectric constant then increased to 103 order of magnitude. 相似文献