全文获取类型
收费全文 | 1314篇 |
免费 | 2篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 109篇 |
金属工艺 | 43篇 |
机械仪表 | 52篇 |
建筑科学 | 18篇 |
矿业工程 | 6篇 |
能源动力 | 5篇 |
轻工业 | 20篇 |
水利工程 | 14篇 |
石油天然气 | 36篇 |
无线电 | 47篇 |
一般工业技术 | 275篇 |
冶金工业 | 569篇 |
原子能技术 | 61篇 |
自动化技术 | 49篇 |
出版年
2021年 | 16篇 |
2019年 | 16篇 |
2018年 | 24篇 |
2017年 | 26篇 |
2016年 | 14篇 |
2014年 | 24篇 |
2013年 | 31篇 |
2012年 | 23篇 |
2011年 | 27篇 |
2010年 | 20篇 |
2009年 | 23篇 |
2008年 | 19篇 |
2007年 | 20篇 |
2006年 | 19篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2000年 | 13篇 |
1999年 | 28篇 |
1998年 | 132篇 |
1997年 | 93篇 |
1996年 | 58篇 |
1995年 | 39篇 |
1994年 | 33篇 |
1993年 | 25篇 |
1992年 | 17篇 |
1990年 | 20篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 20篇 |
1986年 | 18篇 |
1985年 | 13篇 |
1984年 | 18篇 |
1982年 | 13篇 |
1981年 | 33篇 |
1980年 | 21篇 |
1979年 | 21篇 |
1978年 | 16篇 |
1977年 | 34篇 |
1976年 | 48篇 |
1975年 | 17篇 |
1974年 | 16篇 |
1973年 | 21篇 |
1972年 | 14篇 |
1971年 | 19篇 |
1970年 | 12篇 |
1969年 | 15篇 |
1968年 | 10篇 |
1967年 | 10篇 |
1965年 | 12篇 |
排序方式: 共有1316条查询结果,搜索用时 15 毫秒
1.
T.V. Vakalova L.P. Devyashina Sh.M. Sharafeev N.P. Sergeev 《Ceramics International》2021,47(11):15282-15292
One of the drawbacks of fusible clays is the narrow sintering interval due to a sharp increase in the amount of iron-silicate melt at a temperature of 1000–1100 °C, which hardens in the form of a glass phase upon cooling. This leads to a relatively low mechanical strength of the calcined samples and causes the danger of melting the granular material surface from such clays during the firing process. To increase the strength of samples of fusible clays, the influence of diabase and granitoid rocks was considered. It was found that the strengthening effect of diabase and granitoid rock additives in an amount of 20–50% in a mixture with fusible clay is due to an increase of total content of the crystalline phase (mullite, cristobalite and residual quartz) from 18–20% in clays without additives to 22–28 % - in mixtures with diabase and to 28–34% - with granitoid additives) at a temperature of 1050–1100 °C. This increase is due to the activation of synthesis processes of secondary mullite and crystallization from alkali-rich feldspar melt of amorphous silica, released from the structure of clay minerals. The established influence of the igneous rocks used made it possible to develop compositions and propose process flow sheet for producing aluminosilicate proppants based on fusible clays. The use of granitoid and diabase rocks in an amount of 20–70% with fusible clays produces lightweight aluminosilicate proppants with bulk density of 1.40–1.46 g/cm3 at temperature range of 1050–1100 °C, which can endure destructive pressures up to 34.5–52 MPa. 相似文献
2.
A system composed of two heavy holes located in a two-dimensional (2D) quantum well (QW) and bound via mediation of an electron in a neighboring 2D QW is considered. Using a simple qualitative trial wave function, the ground-state energy of this kind of X+ trion is determined in the infinite-hole-mass approximation as a function of the QW spacing. Coordinate dependence of the effective potential binding the holes to each other is calculated for different values of QW spacing. In the adiabatic approximation, a set of dependences describing the X+ trion binding energy as a function of the electron mass to the hole mass ratio is obtained. Several estimates for the trion binding energy in GaAs-and ZnSe-based double-QW heterostructures are given. 相似文献
3.
4.
5.
The storage time before salvaging of decommissioned nuclear-powered submarines and the floating storage time of reactor units from salvaged submarines can total decades. During this time, radioactive contamination of seawater occurs as a result of the corrosion of the pressure hull in the region of the reactor system and rupturing of the pressure hull - as a result of corrosion of the components of the reactor system. A computational analysis shows that under standard storage conditions the specific activity of water is 105–106 times lower than the intervention level. In the case when the hull and the reactor system are destroyed even with remaining fuel, the specific activity of the sea water near the point of sinking also does not exceed the intervention level because of the slow emission of fission products and transuranium nuclides.Translated from Atomnaya Énergiya, Vol. 97, No. 3, pp. 210–218, September, 2004. 相似文献
6.
B. V. Kuteev V. Yu. Sergeev V. A. Belopol’sky V. M. Timokhin R. Burhenn 《Technical Physics Letters》2003,29(4):302-304
Experiments performed on a Wendelstein 7-AS stellarator revealed asymmetry of the cloud of an ablating carbon pellet. The cloud is elongated in the direction of large radius toward stronger fields, that is, opposite to the direction expected due to the toroidal drift. In order to study the effect in more detail, the three-dimensional structure of the cloud was analyzed by computer tomography. The results confirmed asymmetry of the cloud. This asymmetry is related to a drift flow existing in the plasma and directed along large radius toward stronger fields. The drift velocity is numerically estimated at ~300 m/s. 相似文献
7.
SV Varha OH Reznikov IS Turchyn VM Demchenko OP Potikha PV Sinitsyn LV Tarasenko LV Cha?kovs'ka 《Canadian Metallurgical Quarterly》1994,40(5-6):105-109
The effect exerted by transplantation of the 5 day culture of testicles from newly born piglets on the hypogonadal state of mature X-ray irradiated (3 Gy) rats was studied. It has been found that a month after transplantation (two months after irradiation) the hypogonadal state disappeared for a while, which is confirmed by normalization of the weight of seminal vesicles, content of testosterone and biologically active lutropine, restoration of the reproductive function of rats. No significant changes in steroidogenesis activity have been found, which proves a substituent character of transplantation. The effect disappears three months later but certain restoration of the content of nucleic acids in the testicles is observed. 相似文献
8.
9.
PV Rabins 《Canadian Metallurgical Quarterly》1997,277(24):1933-1934
10.