全文获取类型
收费全文 | 583篇 |
免费 | 58篇 |
国内免费 | 19篇 |
专业分类
电工技术 | 27篇 |
综合类 | 42篇 |
化学工业 | 60篇 |
金属工艺 | 1篇 |
机械仪表 | 18篇 |
建筑科学 | 2篇 |
能源动力 | 2篇 |
轻工业 | 31篇 |
石油天然气 | 2篇 |
武器工业 | 9篇 |
无线电 | 272篇 |
一般工业技术 | 6篇 |
原子能技术 | 1篇 |
自动化技术 | 187篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 31篇 |
2013年 | 26篇 |
2012年 | 45篇 |
2011年 | 54篇 |
2010年 | 52篇 |
2009年 | 48篇 |
2008年 | 48篇 |
2007年 | 52篇 |
2006年 | 51篇 |
2005年 | 58篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 25篇 |
2001年 | 17篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有660条查询结果,搜索用时 15 毫秒
61.
Catherine J. Andersen Christopher N. Blesso Jiyoung Lee Jacqueline Barona Dharika Shah Michael J. Thomas Maria Luz Fernandez 《Lipids》2013,48(6):557-567
We recently demonstrated that daily whole egg consumption during moderate carbohydrate restriction leads to greater increases in plasma HDL-cholesterol (HDL-C) and improvements in HDL profiles in metabolic syndrome (MetS) when compared to intake of a yolk-free egg substitute. We further investigated the effects of this intervention on HDL composition and function, hypothesizing that the phospholipid species present in egg yolk modulate HDL lipid composition to increase the cholesterol-accepting capacity of subject serum. Men and women classified with MetS were randomly assigned to consume either three whole eggs (EGG, n = 20) per day or the equivalent amount of egg substitute (SUB, n = 17) throughout a 12-week moderate carbohydrate-restricted (25–30 % of energy) diet. Relative to other HDL lipids, HDL-cholesteryl ester content increased in all subjects, with greater increases in the SUB group. Further, HDL-triacylglycerol content was reduced in EGG group subjects with normal baseline plasma HDL-C, resulting in increases in HDL-CE/TAG ratios in both groups. Phospholipid analysis by mass spectrometry revealed that HDL became enriched in phosphatidylethanolamine in the EGG group, and that EGG group HDL better reflected sphingomyelin species present in the whole egg product at week 12 compared to baseline. Further, macrophage cholesterol efflux to EGG subject serum increased from baseline to week 12, whereas no changes were observed in the SUB group. Together, these findings suggest that daily egg consumption promotes favorable shifts in HDL lipid composition and function beyond increasing plasma HDL-C in MetS. 相似文献
62.
Theodosios D. Filippatos Evangelos C. Rizos Vasilios Tsimihodimos Irene F. Gazi Alexandros D. Tselepis Moses S. Elisaf 《Lipids》2013,48(6):547-555
Alterations in high-density lipoprotein (HDL) subclass distribution, as well as in the activities of HDL-associated enzymes, have been associated with increased cardiovascular disease (CVD) risk. HDL subclass distribution and the activities of HDL-associated enzymes remain unknown in prediabetic patients, a condition also associated with increased CVD risk. The aim of the present study was to assess any differences in HDL subclass distribution (using polyacrylamide gel electrophoresis) and in activities of HDL-associated enzymes between prediabetic (impaired fasting glucose, IFG, n = 80) and non-prediabetic subjects (n = 105). Subjects with prediabetes had significantly increased waist circumference, blood pressure and triacylglycerol (TAG) levels compared with subjects with fasting glucose levels <100 mg/dL (all p < 0.05). The proportion of small HDL3 over HDL cholesterol (HDL-C) was significantly increased in prediabetic subjects compared with their controls (p < 0.05). The activity of the anti-atherogenic HDL-associated lipoprotein-associated phospholipase A2 (HDL-LpPLA2) was significantly lower in subjects with prediabetes (p < 0.05), whereas the activity of paraoxonase 1 (using both paraoxon and phenyl acetate as substrates) did not significantly differ between subjects with or without prediabetes. In a stepwise linear regression analysis, the proportion of small HDL3 over HDL-C concentration was independently associated with the presence of prediabetes and with total cholesterol and TAG concentration (positively), as well as with HDL-C levels (negatively). We also observed a trend of increased small dense low-density lipoprotein cholesterol levels in prediabetic subjects compared with their controls. Subjects with IFG exhibit increased proportion of small HDL3 particles combined with decreased activity of the anti-atherogenic HDL-LpPLA2. 相似文献
63.
Postprandial triglyceride-rich lipoproteins (TRL) levels are a predictor for coronary atherosclerosis. The aim of the study was to compare fasting high density lipoprotein (HDL) cholesterol, plasma lipoprotein lipase (LPL) activity, and postprandial TRL between elderly survivors of myocardial infarction (MI) and healthy controls. A case-control study was performed in 44 elderly patients 65-85 years of age with a previous history of MI and 43 age- and sex-matched healthy controls. Each participant underwent physical examination and was given a standard oral fat load with subsequent blood sampling over the next 8 h. Total and chylomicron triglycerides were assessed by area under the curve (AUC), incremental are under the curve (AUCi) and triglyceride response (TGR). Elderly MI patients had significantly lower postheparin LPL activity (87.4 +/- 36.9 mU/ml) (mean +/- 1 SD) than healthy controls (106.0 +/- 29.0 mU/ml) (P = 0.014). Decreased postheparin LPL activity was accompanied by significant increased and delayed clearance of postprandial TRL. Fasting HDL cholesterol was significantly lower in elderly MI patients than controls (1.45 +/- 0.32 and 1.66 +/- 0.47 mmol/l, respectively, P = 0.048). Multiple regression analysis revealed postheparin LPL activity as an independent predictor for postprandial TRL and fasting HDL cholesterol. Logistic regressions analysis revealed HDL cholesterol, triglycerides measured 2 h after the oral fat load, and postheparin LPL activity as independent predictors for MI. Our findings indicate that decreased fasting HDL cholesterol is associated with increased postprandial triglyceridemia which could be a target for life-style and therapeutic interventions in patients at risk for cardiovascular disease. 相似文献
64.
Li Tian Xinwei Wu Mingde Fu Yanhua Xu Lianqun Jia 《European Journal of Lipid Science and Technology》2008,110(10):879-886
Background and aims: To investigate the impact of plasma apoA‐II concentrations on the alteration of HDL subclass distribution, and the cooperative effect of apoA‐I and apoA‐II on it. Methods and results: The apoA‐I contents of plasma HDL subclasses were quantified by two‐dimensional gel electrophoresis associated with immunodetection for 292 Chinese people. These subjects were divided according to the mean ± 1 SD of apoA‐II and apoA‐I levels as two cut‐points, respectively. Compared with the low‐apoA‐II group, the apoA‐I contents of HDL3a (in the high group), HDL3b, and HDL2b increased strikingly, both in the middle‐ and high‐apoA‐II group. The apoA‐I contents of all HDL subclasses increased progressively when the apoA‐I and apoA‐II levels simultaneously or the apoA‐I/apoA‐II ratio increased, and in comparison to the low‐apoA‐I–A‐II levels group, the apoA‐I contents of HDL2b (115%) increased more significantly than those of preβ1‐HDL (39%) in the high‐apoA‐I–A‐II levels group. Multiple analyses also indicated that the three HDL subclasses, HDL3a, HDL3b and HDL2b, were independently predicted by apoA‐II. Conclusion: Excess apoA‐II can cause the accumulation of both large‐sized HDL2b and small‐sized HDL3, which implies that apoA‐II plays a double role in the HDL maturation metabolism. Meanwhile, the degree of HDL2b increased significantly relative to that of preβ1‐HDL when apoA‐I and apoA‐II levels were elevated simultaneously, suggesting that the maturation and metabolism of HDL might be promoted and reverse cholesterol transport might be enhanced. 相似文献
65.
Nina ukanovi Slobodan Obradovi Marija Zdravkovi Sinia uraevi Maja Stojkovi Tomislav Tosti Neboja Jasni Jelena orevi Zoran Todorovi 《International journal of molecular sciences》2021,22(6)
Lipids play an essential role in platelet functions. It is known that polyunsaturated fatty acids play a role in increasing platelet reactivity and that the prothrombotic phenotype plays a crucial role in the occurrence of major adverse cardiovascular events. The ongoing increase in cardiovascular diseases’ incidence emphasizes the importance of research linking lipids and platelet function. In particular, the rebound phenomenon that accompanies discontinuation of clopidogrel in patients receiving dual antiplatelet therapy has been associated with changes in the lipid profile. Our many years of research underline the importance of reduced HDL values for the risk of such a rebound effect and the occurrence of thromboembolic events. Lipids are otherwise a heterogeneous group of molecules, and their signaling molecules are not deposited but formed “on-demand” in the cell. On the other hand, exosomes transmit lipid signals between cells, and the profile of such changes can be monitored by lipidomics. Changes in the lipid profile are organ-specific and may indicate new drug action targets. 相似文献
66.
67.
68.
给出一种基于FPGA的8051MCU的IP核设计方案,指令集与标准8051系列处理器完全兼容。采用译码——执行两级流水结构,并通过了仿真与综合,理论速度较传统8051MCU有610倍的提升。针对CISC流水线设计的复杂性,提出了一种高效的实现方案,可以使执行结构近满状态运行,且简便有效地解决了传统流水线所必须面对的三种冲突。设计采用Verilog HDL语言描述,并采用ModelsimSE 6.2进行功能和时序验证,将代码下载到Xilinx公司的FPGA上进行物理验证,测试了一个LED流水灯程序,结果表明软核达到了预期的效果。 相似文献
69.
基于Verilog HDL的ADC0809采样控制器设计 总被引:1,自引:0,他引:1
介绍了芯片ADC0809的工作原理和如何利用Verilog HDL硬件描述语言设计ADC0809采样控制电路,同时给出采样控制电路在Quartus Ⅱ4.0软件环境下的功能仿真波形,并通过Altera公司的CPLD器件EPIK30TC144—3和GW48EDA教学试验系统来实现A/D采样控制器。实践证明设计的电路能够稳定、可靠的工作。 相似文献
70.
循环冗余校验(CRC)码是数据通信中广泛应用的一种差错检测码。在介绍CRC原理的基础上,以常见的CRC-16为例,用VerilogHDL硬件描述语言设计该算法。利用Altera公司的EDA开发工具软件QuartusII6.0,给出仿真波形图以及可以共享的模块,该模块既是CRC码生成器,又是待校验数据的校验器。仿真结果表明,这是一种实现CRC算法的有效方法,其工作频率可达到420.17MHz。 相似文献