首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10504篇
  免费   367篇
  国内免费   15篇
工业技术   10886篇
  2023年   61篇
  2022年   86篇
  2021年   126篇
  2020年   110篇
  2019年   131篇
  2018年   167篇
  2017年   147篇
  2016年   214篇
  2015年   187篇
  2014年   311篇
  2013年   544篇
  2012年   443篇
  2011年   482篇
  2010年   351篇
  2009年   426篇
  2008年   366篇
  2007年   333篇
  2006年   338篇
  2005年   290篇
  2004年   276篇
  2003年   254篇
  2002年   277篇
  2001年   206篇
  2000年   186篇
  1999年   254篇
  1998年   1173篇
  1997年   688篇
  1996年   450篇
  1995年   285篇
  1994年   255篇
  1993年   289篇
  1992年   80篇
  1991年   104篇
  1990年   99篇
  1989年   101篇
  1988年   81篇
  1987年   77篇
  1986年   62篇
  1985年   52篇
  1984年   30篇
  1983年   25篇
  1982年   20篇
  1981年   37篇
  1980年   47篇
  1979年   12篇
  1978年   19篇
  1977年   84篇
  1976年   202篇
  1975年   10篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
1. Effects of feeding condition from birth were examined on the sensitivity of neuromuscular transmission to d-tubocurarine (dTc) in vitro in male mice of the ddY strain. 2. Mice were trained to climb two separated cylindrical steel-wire tubes for feeding and drinking, respectively, from 16 days of age. Some mice were conventionally fed, from 99 days of age. Nerve-muscle preparations were made from the left phrenic nerve diaphragm muscle (DPH), the sciatic nerve soleus muscle (SOL), and the sciatic nerve extensor digitorum longus muscle (EDL) of 99-day-old and 155-day-old mice. The nerve trunk was electrically activated with trains of four pulses and tetanic pulses. 3. The sensitivity to the effects of dTc decreased in the order EDL, SOL, and DPH. This result held true in all mice tested. 4. This sensitivity was significantly potentiated by the compulsory movement. 5. The supersensitivity remained even when mice were conventionally fed after 99 days of age. 6. The compulsion rendered EDL antifatigable on tetanic stimulation. This property was also retained after a return to conventional feeding. 7. These results suggest that the effects of feeding condition from birth might remain on neuromuscular functions after termination of the conditioning.  相似文献   
44.
GaN buffer and main layers were grown by the conventional hydride vapor phase epitaxy technique using GaCl3 consecutively. The deposited buffer layers were investigated by atomic force microscopy and X-ray analysis. To examine the behavior of the buffer layers at main layer growth temperature, heat treatment was conducted at 900°C. Based on the results of the buffer layer study, GaN thick films were grown at 1050°C. Optimum deposition conditions of buffer layer from the buffer and main layer studies generally coincided. On the φ scanning pattern, the GaN films grown on (0001) Al2O3 were single-crystalline. Band-edge emission dominated photoluminescence was observed at room temperature.  相似文献   
45.
46.
47.
48.
Equilibrium solidification in a semitransparent planar layer is studied using an isothermal mushy zone model. The layer is made up of a pure material being emitting, absorbing and isotropically scattering and is subject to radiative and convective cooling. The model involves solving simultaneously the transient energy equation and the radiation transport equation. An implicit finite volume scheme is employed to solve the energy equation, with the discrete ordinate method being used to deal with the radiation transport. A systematical parametric study is performed and the effects of various materials optical properties and processing conditions are investigated. It is found that decreasing the optical thickness and increasing the scattering albedo both lead to a wider mushy zone and a slower rate of solidification.  相似文献   
49.
50.
A systematic study of wall effects on the shear viscosity of short glass fiber-filled polypropylene and polystyrene is presented. The dependence of these effects on capillary radius, shear rate, temperature, and polymer matrix is examined. The “true” viscosity curves of these materials (free from wall effects) can be obtained by an extrapolation procedure. Breakage of glass fibers in the high shear-rate processes of extrusion and injection molding lead to an appreciable reduction of the viscosity of these materials and is probably the more important effect to take into account in these processes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号