全文获取类型
收费全文 | 4590篇 |
免费 | 396篇 |
国内免费 | 293篇 |
专业分类
电工技术 | 391篇 |
综合类 | 349篇 |
化学工业 | 421篇 |
金属工艺 | 379篇 |
机械仪表 | 286篇 |
建筑科学 | 247篇 |
矿业工程 | 151篇 |
能源动力 | 69篇 |
轻工业 | 370篇 |
水利工程 | 93篇 |
石油天然气 | 106篇 |
武器工业 | 83篇 |
无线电 | 269篇 |
一般工业技术 | 266篇 |
冶金工业 | 1259篇 |
原子能技术 | 75篇 |
自动化技术 | 465篇 |
出版年
2024年 | 32篇 |
2023年 | 56篇 |
2022年 | 133篇 |
2021年 | 185篇 |
2020年 | 133篇 |
2019年 | 106篇 |
2018年 | 87篇 |
2017年 | 101篇 |
2016年 | 90篇 |
2015年 | 136篇 |
2014年 | 186篇 |
2013年 | 254篇 |
2012年 | 348篇 |
2011年 | 334篇 |
2010年 | 307篇 |
2009年 | 271篇 |
2008年 | 284篇 |
2007年 | 295篇 |
2006年 | 236篇 |
2005年 | 168篇 |
2004年 | 124篇 |
2003年 | 84篇 |
2002年 | 52篇 |
2001年 | 57篇 |
2000年 | 47篇 |
1999年 | 51篇 |
1998年 | 343篇 |
1997年 | 213篇 |
1996年 | 138篇 |
1995年 | 81篇 |
1994年 | 74篇 |
1993年 | 61篇 |
1992年 | 6篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1977年 | 48篇 |
1976年 | 85篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1966年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有5279条查询结果,搜索用时 15 毫秒
1.
图形点阵式液晶显示器MSP-G320240在高速处理器DSP中的应用 总被引:1,自引:1,他引:0
介绍了内置SD1335控制器的图形液晶显示器MSP-G320240的工作原理及应用方法,给出了MSP-G320240液晶显示器同DSP的简单接口电路,同时给出了相应的液晶显示器的初始化和清显示区的具体程序。 相似文献
2.
3.
4.
5.
6.
Comparison evaluation of the methods of treatment was based on the analysis of the results of management of 347 patients with general purulent decompensated peritonitis with polyorganic insufficiency. The efficacy of closed drainage in 98 patients, continuous flow irrigation (dialysis) in 126, stage programmed irrigation and inspection of the abdominal cavity in 99, and open drainage in 24 patients was compared. The causes of peritonitis were: complications after acute surgical diseases (in 156 cases), in planned operations (59), and in obstetrical and gynecological diseases (132). Most of the patients were brought to the clinic from other hospitals because of unsuccessful treatment of peritonitis and absence of means for performing hemodialysis and management of polyorganic insufficiency. The incidence of the last-named reached 71.0 to 91.0% in the different groups of patients. In monotypic complex treatment, stage programmed irrigation was marked by a much lesser number of abscesses and other complications and a lower mortality (20.2%) as compared to flow irrigation (30.0%, closed drainage (27.5%), and open (laparostomy) treatment (37.5%). Despite the very serious contingent of patients, total mortality (27.0%) in the application of the indicated methods was quite low. 相似文献
7.
Cytochrome c oxidase isolated from a wild-type yeast strain and a mutant in which the gene for subunit VIa had been disrupted were used to study the interaction of adenine nucleotides with the enzyme complex. At low ionic strength (25 mM potassium phosphate), in the absence of nucleotides, the cytochrome c oxidase activity of the mutant enzyme lacking subunit VIa was higher than that of the wild-type enzyme. Increasing concentrations of ATP, in the physiological range, enhanced the cytochrome c oxidase activity of the mutant much more than the activity of the wild-type strain, whereas ADP, in the same concentration range, had no significant effect on the activity of the cytochrome c oxidase of either strain. These results indicate an interaction of ATP with subunit VIa in the wild-type enzyme that prevents the stimulation of the activity observed in the mutant enzyme. The stimulation of the mutant enzyme implies the presence of a second ATP binding site on the enzyme. Quantitative titrations with the fluorescent adenine nucleotide analogues 2'(or 3')-O-(2,4,6-trinitrophenyl)adenosine 5'-triphosphate (TNP-ATP) and 2'(or 3')-O-(2,4,6-trinitrophenyl)adenosine 5'-diphosphate (TNP-ADP) confirmed the presence of two binding sites for adenine nucleotides per monomer of wild-type cytochrome c oxidase and one binding site per monomer of mutant enzyme. Covalent photolabeling of yeast cytochrome c oxidase with radioactive 2-azido-ATP further confirmed the presence of an ATP binding site on subunit VIa.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
9.
In this study we have employed the whole cell patch clamp technique to investigate the effects of an anti-cancer drug cisplatin on basic electrophysiological properties of cultured dorsal root ganglion neurones from neonatal rats. The results show that within the clinical concentration range, cisplatin (0.1 to 10 microM) caused a decrease in input conductance, and complex changes in resting membrane potential in these cultured sensory neurones. The dominant effects of cisplatin on input conductance may be due to inhibition of leak conductances. Transplatin (5 microM) was significantly less effective than cisplatin at reducing input conductance which suggests a degree of stereoselectivity. Cisplatin (1 to 5 microM) transiently increased excitability of the cultured neurones as reflected by a reduction in the threshold for activation of action potentials by 8 mV. The rise time, peak amplitude and duration of action potentials were not changed by acute application of 5 microM cisplatin. Long term treatment of neurones with cisplatin (5 microM), for up to 1 week reduced the viability of the cultures, and attenuated neurone excitability, although input conductance of the cells was significantly increased to 322 +/- 49 M omega (n = 9) compared with controls of 210 +/- 20 M omega (n = 30; P < 0.05). Acute and chronic treatment of cultured neurones with cisplatin therefore produced contrasting actions. 相似文献
10.
MI Matee EF Lyamuya E Simon EC Mbena C Kagoma LP Samaranayake F Scheutz 《Canadian Metallurgical Quarterly》1996,73(5):292-294
The present study, based on 158 HIV seropositives and 167 HIV seronegatives, demonstrates that saliva collected with the Omni-SAL device and tested with GACELISA (an IgG antibody capture ELISA) is an effective non-invasive alternative to serum for anti-HIV IgG antibody screening. The study also shows that a conventional serum Western blot kit can be used, with slight modifications, for confirmatory testing of saliva specimens. Collecting saliva with the Omni-SAL device had a very good acceptance rate among Tanzanian subjects, and although this diagnostic method is not yet known by the general public, 65% of the study participants preferred to give saliva instead of blood for HIV testing. 相似文献