全文获取类型
收费全文 | 1518篇 |
免费 | 47篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 87篇 |
综合类 | 6篇 |
化学工业 | 344篇 |
金属工艺 | 27篇 |
机械仪表 | 24篇 |
建筑科学 | 29篇 |
能源动力 | 60篇 |
轻工业 | 119篇 |
水利工程 | 5篇 |
石油天然气 | 6篇 |
无线电 | 142篇 |
一般工业技术 | 262篇 |
冶金工业 | 274篇 |
原子能技术 | 54篇 |
自动化技术 | 130篇 |
出版年
2022年 | 6篇 |
2021年 | 28篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 18篇 |
2017年 | 24篇 |
2016年 | 20篇 |
2015年 | 15篇 |
2014年 | 23篇 |
2013年 | 54篇 |
2012年 | 58篇 |
2011年 | 63篇 |
2010年 | 71篇 |
2009年 | 73篇 |
2008年 | 71篇 |
2007年 | 55篇 |
2006年 | 41篇 |
2005年 | 47篇 |
2004年 | 45篇 |
2003年 | 47篇 |
2002年 | 39篇 |
2001年 | 39篇 |
2000年 | 30篇 |
1999年 | 32篇 |
1998年 | 104篇 |
1997年 | 73篇 |
1996年 | 51篇 |
1995年 | 48篇 |
1994年 | 42篇 |
1993年 | 31篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 16篇 |
1988年 | 20篇 |
1987年 | 14篇 |
1986年 | 26篇 |
1985年 | 22篇 |
1984年 | 22篇 |
1983年 | 18篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 13篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 8篇 |
排序方式: 共有1569条查询结果,搜索用时 15 毫秒
11.
We investigated intestinal ethanol absorption in rats pretreated with saline, cyanamide, 4-methylpyrazole and cyanamide + 4-methylpyrazole. The value of the absorption rate constant in the cyanamide-pretreated group with high acetaldehyde levels was the lowest among the four groups, but there were no significant differences among the remaining groups. We found that high acetaldehyde concentration itself clearly reduces intestinal ethanol absorption. 相似文献
12.
This paper presents a partial scan algorithm, calledPARES (PartialscanAlgorithm based onREduced Scan shift), for designing partial scan circuits. PARES is based on the reduced scan shift that has been previously proposed for generating short test sequences for full scan circuits. In the reduced scan shift method, one determines proch FFs must be controlled and observed for each test vector. According to the results of similar analysis, PARES selects these FFs that must be controlled or observed for a large number of test vectors, as scanned FFs. Short test sequences are generated by reducing scan shift operations using a static test compaction method. To minimize the loss of fault coverage, the order of test vectors is so determined that the unscanned FFs are in the state required by the next test vector. If there are any faults undetected yet by a test sequence derived from the test vectors, then PARES uses a sequential circuit test generator to detect the faults. Experimental results for ISCAS'89 benchmark circuits are given to demonstrate the effectiveness of PARES. 相似文献
13.
Swelling degrees of poly(N-vinyl-2-pyrrolidone) (PVP) gel were measured in aqueous salt solutions and in water/organic solvent mixtures to find marked ion- and solvent-specificities. In order to investigate any correlation of those specificities with hydration or solvation of PVP, IR spectra band of the CO group was monitored by means of ATR method both for PVP gel and the relevant solution systems. Dependence of the peak frequency on the swelling ratio suggested that hydration of PVP carbonyl group in deswollen gel systems is different from that in the corresponding solution systems. In the solution systems, PVP carbonyl band showed a high-wavenumber shift for deswollen systems, which can be well correlated with changes in water proton charge through ionic hydration and with Gutmann's acceptor number of organic solvents. In the deswollen gel systems, the CO band showed a low-wavenumber shift, suggesting a strong hydration or doubly hydrated state. This unexpected behavior was interpreted by assuming an intermolecular hydrogen bond of two carbonyl groups intermediated by water molecules. 相似文献
14.
Authorship and citation patterns in Management Science in comparison with operational research 总被引:1,自引:1,他引:0
The authorship and citation patterns in the journal titled Management Science (MS) are analysed. The purpose of the analysis is to examine the competitive relation of MS with OR (operational research
or operations research). The analysis is focused on the use of mathematical methods, because MS entered the management research
area by using mathematical methods developed by OR and because the use of mathematical methods in real management is facing
difficulties. The relationship of MS with information systems (IS) and organisation research (Org) is analysed in regard to
the competition of MS with OR. The analysis reveals the intermediate character of MS; that is, MS is less prone to mathematical
methods and is more inclined towards IS and Org than OR is.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
15.
In the drying of coated films with dispersed pigments, such as floppy disks, the structure of the film is formed during the drying process and depends on the drying condition. It is important to understand the structure formation during drying for the design of the dryer and die better quality of the product. We measured die drying characteristics of the film and determined the structure of dried film experimentally. A qualitative model for the structure formation during drying of the coated film is suggested. 相似文献
16.
K Ikeda E Satoyoshi M Kinoshita N Wakata Y Iwasaki 《Canadian Metallurgical Quarterly》1998,37(9):784-787
Satoyoshi syndrome consists of painful intermittent muscle spasms, alopecia and diarrhea. The age of onset is commonly less than 20 years of age. Adult onset of this syndrome is rare. We report a 65-year-old Japanese woman with Satoyoshi's syndrome of adult onset. Satoyoshi's syndrome of adult onset shows no skeletal abnormalities, in comparison with the classical pediatric cases. The clinical features in our patient revealed the benign and long-term course of muscle spasm and alopecia. This progression differed markedly from the other patients of adult onset. Thus, the severity of Satoyoshi's syndrome is variable in adult onset cases, and this diagnosis should be considered in adults with various and unexplained muscle spasms. 相似文献
17.
Satoshi Nishimura Zhi-Gang Zhang Ken-Ichiro Sugiyama Izumi Kinoshita 《Nuclear Engineering and Design》2007,237(23):2201-2209
In order to clarify the fragmentation mechanism of a metallic alloy (U–Pu–Zr) fuel on liquid phase formed by metallurgical reactions (liquefaction temperature = 650 °C), which is important in evaluating the sequence of core disruptive accidents for metallic fuel fast reactors, a series of experiments was carried out using molten aluminum (melting point = 660 °C) and sodium mainly under the condition that the boiling of sodium does not occur. When the instantaneous contact interface temperature (Ti) between molten aluminum drop and sodium is lower than the boiling point of sodium (Tc,bp), the molten aluminum drop can be fragmented and the mass median diameter (Dm) of aluminum fragments becomes small with increasing Ti. When Ti is roughly equivalent to or higher than Tc,bp, the fragmentation of aluminum drop is promoted by thermal interaction caused by the boiling of sodium on the surface of the drop. Furthermore, even under the condition that the boiling of sodium does not occur and the solid crust is formed on the surface of the drop, it is confirmed from an analytical evaluation that the thermal fragmentation of molten aluminum drop with solid crust has a potential to be caused by the transient pressurization within the melt confined by the crust. These results indicate the possibility that the metallic alloy fuel on liquid phase formed by the metallurgical reactions can be fragmented without occurring the boiling of sodium on the surface of the melt. 相似文献
18.
19.
Various liquid polybutadiene derivatives were examined as modifiers to improve the brittleness of phenolic resins. Amidated polybutadienes obtained from a maleinated polybutadiene and ammonia had the highest curing tendency when they were reacted with resole under mild conditions. The cured resins were homogeneous and the brittleness of the phenolic resins was remarkably improved. Crosslinking efficiency was closely related to the succinamic acid group of the amidated polybutadiene. Thermal behavior of the succinamic acid group was also related to the effects of curing temperature and curing time on crosslinking. From these observations, cross-condensation between the succinamic acid group of an amidated polybutadiene and resole seemed to have occurred to a great extent than the self-condensation of resole itself and oxidative crosslinking of the amidated polybutadiene. 相似文献
20.
Okamura H. Atsumo T. Takeda K. Takada M. Imai K. Kinoshita Y. Yamazaki T. 《Solid-State Circuits, IEEE Journal of》1996,31(1):84-90
A BiCMOS logic circuit with very small input capacitance has been developed, which operates at low supply voltages. A High-beta BiCMOS (Hβ-BiCMOS) gate circuit which fully utilizes the bipolar transistor features achieves 10 times the speed of a CMOS gate circuit with the same input capacitance and operating at 3.3 V supply voltage. In order to lower the minimum supply voltage of Hβ-BiCMOS, a BiCMOS circuit configuration using a charge pump to pull up the output high level of the BiCMOS gate circuit is proposed. By introducing a BiCMOS charge pump, Hβ-BiCMOS achieves very high speed operation at sub-2.0 V supply voltage. It has also been demonstrated that only a very small number of charge pump circuits are required to drive a large number of Hβ-BiCMOS gate circuits 相似文献