全文获取类型
收费全文 | 403820篇 |
免费 | 4696篇 |
国内免费 | 1364篇 |
专业分类
电工技术 | 7572篇 |
综合类 | 316篇 |
化学工业 | 59839篇 |
金属工艺 | 16424篇 |
机械仪表 | 13488篇 |
建筑科学 | 8354篇 |
矿业工程 | 2154篇 |
能源动力 | 11531篇 |
轻工业 | 28475篇 |
水利工程 | 4270篇 |
石油天然气 | 7915篇 |
武器工业 | 17篇 |
无线电 | 49251篇 |
一般工业技术 | 82990篇 |
冶金工业 | 74958篇 |
原子能技术 | 9181篇 |
自动化技术 | 33145篇 |
出版年
2022年 | 2556篇 |
2021年 | 3888篇 |
2020年 | 2947篇 |
2019年 | 3808篇 |
2018年 | 6490篇 |
2017年 | 6485篇 |
2016年 | 6928篇 |
2015年 | 4320篇 |
2014年 | 7143篇 |
2013年 | 20032篇 |
2012年 | 11418篇 |
2011年 | 15275篇 |
2010年 | 12152篇 |
2009年 | 13718篇 |
2008年 | 14052篇 |
2007年 | 13820篇 |
2006年 | 12416篇 |
2005年 | 11112篇 |
2004年 | 10506篇 |
2003年 | 10417篇 |
2002年 | 9829篇 |
2001年 | 9733篇 |
2000年 | 9134篇 |
1999年 | 9522篇 |
1998年 | 24328篇 |
1997年 | 16708篇 |
1996年 | 12797篇 |
1995年 | 9517篇 |
1994年 | 8362篇 |
1993年 | 8379篇 |
1992年 | 6055篇 |
1991年 | 5695篇 |
1990年 | 5679篇 |
1989年 | 5318篇 |
1988年 | 5043篇 |
1987年 | 4419篇 |
1986年 | 4299篇 |
1985年 | 4812篇 |
1984年 | 4422篇 |
1983年 | 3994篇 |
1982年 | 3654篇 |
1981年 | 3730篇 |
1980年 | 3429篇 |
1979年 | 3326篇 |
1978年 | 3334篇 |
1977年 | 3750篇 |
1976年 | 4847篇 |
1975年 | 2850篇 |
1974年 | 2663篇 |
1973年 | 2730篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
GOURI S. CHAUHAN R.R. ZILLMAN N.A. MICHAEL ESKIN 《International Journal of Food Science & Technology》1992,27(6):701-705
Flour blends of quinoa-wheat containing 0, 5, 10, 15, and 20% of manually dehulled quinoa meal or flour were evaluated for dough mixing and breadmaking properties and liking of the bread by a small panel. Increasing amounts of quinoa meal or flour increased farinograph absorption and dislike of bread for most of the panel. Dough development time increased with increase in meal but decreased with increase in quinoa flour. At 10% inclusion levels differences in liking from control 100% wheat flour bread were smaller for flour or water extracted meal to most of the panel, than with 10% non-extracted meal. This suggests that 10% inclusion of flour or water extracted meal may have potential for further investigation. 相似文献
922.
P. K. Khare J. M. Keller M. S. Gaur Ranjeet Singh S. C. Datt 《Polymer International》1994,35(4):337-343
The electrical conductivity of solution-grown ethyl cellulose (EC) films, 5–30 μm thick, has been studied in the sandwich configuration (metal–EC–metal) as a function of iodine concentration from 0.5 to 5.0 wt% ratio. The studies were conducted in the temperature range 333–383 K, while the field was varied over the range (3.0–5.5) × 104V/cm. Aluminium was used as the lower electrode, while the upper electrode was of Al, Ag, Cu, Au or Sn. Certain transient effects such as a large burst of current immediately after the application of field were observed. An attempt was made to identify the nature of the current by comparing the observed dependence on electric field, electrode material and temperature with the respective characteristic features of the existing theories of electrical conduction. The results show that the electrical conduction follows Ohm's law at lower fields, while at higher fields, space-charge limited current (SCLC) was observed. It was also found that Richardson–Schottky emission was responsible, to some extent, for the transport of charge carriers in the polymer. The conductivity of the films increased on doping with iodine. The dopant molecules are considered to act as additional trapping centes and provide links between the polymer molecules in the amorphous region, thus resulting in the formation of charge transfer complexes. 相似文献
923.
The change to lead-free solders means that circuit board inspection will become more important than ever. The author investigates differences between lead and lead-free solders. 相似文献
924.
A new method for simulation of truncated random variables is described. Several similar methods are considered. It is shown that a substantial reduction in computation time is achieved by utilizing the proposed method.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 12–13, April, 1995. 相似文献
925.
S. M. Ostroumov 《Journal of Engineering Physics and Thermophysics》1992,62(6):559-562
It was shown that, under thermal loads that are sufficiently larger (smaller) than a certain value, the heat transfer coefficient for porous-sublimation cooling increases (decreases) with an increase in the thermal load.Physico-Technical Low Temperatures Institute, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Inzlieneron-Fizicheskii Zhurnal, Vol. 62, No. 6, pp. 783–785, June, 1992. 相似文献
926.
927.
V. S. Kolobashkin 《Chemical Engineering Communications》1991,107(1):73-94
The work examines the problem of constructing an admissible operation condition domain for a well-stirred reactor which would satisfy restrictions in conversion, selectivity, heat removal and stability. The domain is very important and must be known during the reactor design and control stages because it yields visual information for analyzing the reactor operations and makes it possible to find the variation intervals of decision variables, necessary to calculate and optimize the reactor. Being known, the admissible operation condition domain makes it possible to estimate the limiting restrictions and to choose the necessary reserves. The domain has completely been studied analytically for chemical processes with arbitrary kinetics. 相似文献
928.
Kalustyan É. S. 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1994,28(5):258-265
Power Technology and Engineering - 相似文献
929.
The regular associated solution model for binary systems has been modified by incorporating the size of the complex as an
explicit variable. The thermodynamic properties of the liquid alloy and the interactions between theA
μB type of complex and the unassociated atoms in anA-B binary have been evaluated as a function of relative size of the complex using the activity coefficients at infinite dilution
and activity data at one other composition in the binary. The computational procedure adopted for determining the concentration
of clusters and interaction energies in the associated liquid is similar to that proposed by Lele and Rao. The analysis has
been applied to the thermodynamic mixing functions of liquid Al-Ca alloys believed to contain Al2Ca associates. It is found that the size of the cluster significantly affects the interaction energies between the complex
and the unassociated atoms, while the equilibrium constant and enthalpy change for the association reaction exhibit only minor
variation, when the equations are fitted to experimental data. The interaction energy between unassociated free atoms remains
virtually unaltered as the size of the complex is varied between extreme values. Accurate data on free energy, enthalpy, and
volume of mixing at the same temperature on alloy systems with compound forming tendency would permit a rigorous test of the
proposed model. 相似文献
930.
Intelligent assistance for software development and maintenance 总被引:2,自引:0,他引:2
An environment is described, called Professor Marvel, that provides early error checking and answers questions about the program under development. The environment has a certain understanding of the systems being developed and how to use tools to produce software. It aids individual programmers and helps coordinate programming teams. The key components of Marvel are a database that stores data represented as objects, as in object-oriented languages, and a model of the development process that imposes a structure on programming activities. Marvel's support of insight and of opportunistic processing is discussed at length, as is the handling of side effects. A sample session is described 相似文献