首页 | 本学科首页   官方微博 | 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   271篇
  免费   10篇
电工技术   16篇
化学工业   55篇
金属工艺   1篇
机械仪表   4篇
建筑科学   13篇
能源动力   7篇
轻工业   23篇
无线电   24篇
一般工业技术   84篇
冶金工业   45篇
原子能技术   3篇
自动化技术   6篇
  2023年   1篇
  2022年   3篇
  2021年   5篇
  2020年   4篇
  2019年   1篇
  2018年   9篇
  2017年   4篇
  2016年   1篇
  2015年   3篇
  2014年   4篇
  2013年   10篇
  2012年   16篇
  2011年   15篇
  2010年   7篇
  2009年   12篇
  2008年   11篇
  2007年   13篇
  2006年   15篇
  2005年   9篇
  2004年   8篇
  2003年   15篇
  2002年   6篇
  2001年   3篇
  2000年   6篇
  1999年   5篇
  1998年   11篇
  1997年   9篇
  1996年   7篇
  1995年   7篇
  1994年   6篇
  1993年   2篇
  1992年   7篇
  1991年   4篇
  1990年   4篇
  1989年   6篇
  1988年   1篇
  1987年   6篇
  1986年   4篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1977年   4篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1967年   1篇
排序方式: 共有281条查询结果,搜索用时 859 毫秒
91.
This paper presents a flexible and compact rescue jack system that uses a hydrogen-absorbing alloy as its pressure source. The jack system comprises a container for the hydrogen-absorbing alloy and an end effector thin enough to be applied within a 2 mm-thick gap, made of a fiber-reinforced rubber bag. The hydrogen-absorbing alloy (LaNi4.45Co0.5Mn0.05), whose plateau pressure was set to near atmospheric pressure at 25 °C, released hydrogen gas when heated to 50 °C. Experiments showed the system could lift 100 kg at moderate speed when the alloy container was placed in hot water (50 °C). Moreover, the jack system could maintain a 50 mm lift of 100 kg for nearly 12 h—performance comparable with that of an air jack. This clearly indicates the fiber-reinforced rubber bag is a suitable end effector of the actuator. The proposed jack system has good potential for prompt rescue activities conducted by non-professional operatives.  相似文献   
92.
Thermotropic liquid‐crystalline (LC) electrolytes for lithium‐ion batteries are developed for the first time. A rod‐like LC molecule having a cyclic carbonate moiety is used to form self‐assembled two‐dimensional ion‐conductive pathways with lithium salts. Electrochemical and thermal stability, and efficient ionic conduction is achieved for the liquid crystal. The mixture of the carbonate derivative and lithium bis(trifluoromethylsulfonyl)imide is successfully applied as an electrolyte in lithium‐ion batteries. Reversible charge–discharge for both positive and negative electrodes is observed for the lithium‐ion batteries composed of the LC electrolyte.  相似文献   
93.
The effects of milk products fermented by Bifidobacterium longum strain BL1, a probiotic strain, on blood lipids in rats and humans were studied. Rats were fed a cholesterol-enriched experimental diet, supplemented with lyophilized powders of 1) acid milk (control), 2) milk fermented with a mixed culture of ordinary yogurt starters composed of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (SL), and 3) bifidobacterium milk fermented with the probiotic B. longum strain BL1, respectively. The bifidobacterium milk feeding brought about significant lowering of the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, and triglycerides, in comparison with the control, while no change in high-density lipoprotein cholesterol concentration was observed. On the other hand, supplementation with SL milk resulted in only slight, nonsignificant decreases in serum lipid concentrations in comparison with the control. In the human study, 32 subjects with serum total cholesterol ranging from 220 to 280 mg/dl were randomly assigned to two treatments: 1) intake of a low-fat drinking yogurt prepared with ordinary yogurt starters composed of S. thermophilus and L. delbrueckii subsp. bulgaricus (P-group) and 2) intake of a low-fat drinking yogurt prepared with the two ordinary yogurt starters plus B. longum strain BL1 (B-group). After intake for 4 wk at 3 x 100 ml/day, reduction of serum total cholesterol was observed in approximately half of the B-group subjects; a particularly significant decrease in serum total cholesterol was found among subjects with moderate hypercholesterolemia (serum total cholesterol > 240 mg/dl). However, the serum lipid concentrations in the P-group subjects were almost stable during the experimental periods. The present results indicate the potential of the probiotic B. longum strain BL1 in serum lipid improvement.  相似文献   
94.
A sensitive and specific method for assaying serum mizoribine levels that can be applied to general automatic clinical analyzers was developed. Regression analysis of the enzymatic assay (y) vs. the HPLC method (x) produced the following relation: y=0.964x+0.090 (n=262, Sy, x=6.37 ng/mL).  相似文献   
95.
The relationship between antiferromagnetic (AF) fluctuation and superconductivity was investigated in the La1111 series, LaFeAsO1−x F x (x=0.05, 0.08, and 0.14) by examining nuclear relaxation rates (1/T 1) at both ambient pressure and 3.0 GPa. Although the AF fluctuation is enhanced by applying pressure in the underdoped regime (x=0.05, and 0.08), the increase in critical transition temperature (T c) is small, whereas T c increases remarkably in the overdoped regime (x=0.14) where the AF fluctuation is absent, suggesting that high T c above 40 K originates not from the AF fluctuation but from the density of states at the electron pocket.  相似文献   
96.
The effect of fermented milk supplemented with whey protein concentrate on the serum lipid level of rats was investigated. The serum total cholesterol level for the group fed fermented milk with both Lactobacillus casei TMC0409 and Streptococcus thermophilus TMC 1543 was significantly lower than that of the control group (P<0.05) in rats. Furthermore, the effect of the longterm intake of this fermented milk on the serum lipid level of twenty healthy adult men was investigated. During the 8-wk study, the volunteers consumed 200 ml of fermented milk or placebo in the morning and evening. Blood samples were drawn for analysis three times, just before taking the experimental diet, and after 4 wk and 8 wk of consumption. After 8 wk, the high density lipoprotein cholesterol level for the fermented milk group showed a significant rise after 4 wk (P<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The triglyceride level for the fermented milk group lowered significantly after 4 wk (<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The atherogenic index [(total cholesterol - high density lipoprotein cholesterol)/high-density lipoprotein cholesterol] for the fermented milk group decreased significantly from 4.24 to 3.52 (P<0.05). The systolic blood pressure lowered significantly by the intake of fermented milk (P<0.05) On the other hand, such effect was not observed in the placebo group (P>0.05). These results indicate potential of the development of fermented milk with multiple therapeutic effects.  相似文献   
97.
98.
99.
A 19-year-old man developed paralysis of the left arm as a result of left brachial plexus injury by a traffic accident. He underwent operation for the brachial plexus paralysis, and then severe heart failure developed postoperatively. Echocardiography revealed severe tricuspid valve regurgitation. Tricuspid valve plasty was performed 14 months after the traffic accident. The anterior leaflet of the tricuspid valve was torn and the chordae attached there were torn as well. The torn anterior leaflet was sutured directly, and the prolapsed portion of this leaflet was collected by transfer of the elongated chordae. Annuloplasty (DeVega technique) was then added. Postoperative echocardiography revealed trivial regurgitation of the tricuspid valve. Only 9 cases of successful repair of traumatic tricuspid regurgitation have been reported in Japan.  相似文献   
100.
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