全文获取类型
收费全文 | 7501篇 |
免费 | 474篇 |
国内免费 | 60篇 |
专业分类
电工技术 | 143篇 |
综合类 | 56篇 |
化学工业 | 1734篇 |
金属工艺 | 247篇 |
机械仪表 | 230篇 |
建筑科学 | 395篇 |
矿业工程 | 48篇 |
能源动力 | 493篇 |
轻工业 | 1106篇 |
水利工程 | 59篇 |
石油天然气 | 96篇 |
武器工业 | 12篇 |
无线电 | 371篇 |
一般工业技术 | 1192篇 |
冶金工业 | 631篇 |
原子能技术 | 93篇 |
自动化技术 | 1129篇 |
出版年
2024年 | 23篇 |
2023年 | 75篇 |
2022年 | 152篇 |
2021年 | 279篇 |
2020年 | 218篇 |
2019年 | 211篇 |
2018年 | 327篇 |
2017年 | 325篇 |
2016年 | 347篇 |
2015年 | 263篇 |
2014年 | 362篇 |
2013年 | 831篇 |
2012年 | 413篇 |
2011年 | 499篇 |
2010年 | 431篇 |
2009年 | 407篇 |
2008年 | 342篇 |
2007年 | 329篇 |
2006年 | 216篇 |
2005年 | 144篇 |
2004年 | 176篇 |
2003年 | 160篇 |
2002年 | 197篇 |
2001年 | 133篇 |
2000年 | 104篇 |
1999年 | 87篇 |
1998年 | 181篇 |
1997年 | 117篇 |
1996年 | 78篇 |
1995年 | 58篇 |
1994年 | 79篇 |
1993年 | 54篇 |
1992年 | 31篇 |
1991年 | 20篇 |
1990年 | 24篇 |
1989年 | 26篇 |
1988年 | 21篇 |
1987年 | 10篇 |
1986年 | 15篇 |
1985年 | 33篇 |
1984年 | 25篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 23篇 |
1980年 | 16篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 27篇 |
1975年 | 10篇 |
1974年 | 11篇 |
排序方式: 共有8035条查询结果,搜索用时 343 毫秒
31.
在西西伯利亚俄罗斯油田开展了注凝析油开发稠油的研究,现场实验结果表明,注入25%的凝析油,可使其混合液粘度达到原高粘油粘度的1/60,以俄罗斯油田为例,探讨了注凝析油矿场试验的可行性,预测了凝析油的用量和可能产出的油量,并对原油外输提出了一系列更换工艺设备的要求。 相似文献
33.
In a patient wounded by a gunshot in the abdomen, the bullet was radiologically located intradurally at S1 level. Although she had no neurological deficit at admission, she developed pain and motor weakness a few days later. At operation the bullet was found at L4 level and its removal resulted in complete neurological recovery. 相似文献
34.
OM Takayanagui AA Castro e Silva RC Santiago NS Odashima VC Terra AM Takayanagui 《Canadian Metallurgical Quarterly》1996,54(4):557-564
Cysticercosis is a severe public health problem in several regions of Asia, Africa and Latin America. Epidemiologic studies based on the frequency of cases observed in specialized neurology, neurosurgery and computed tomography services, at autopsy and in seroepidemiologic studies do not permit the determination of the true prevalence of the disease in the population. The objective of the present study was to investigate the prevalence of cysticercosis by compulsory notification. The coefficient of prevalence was 54 cases/100,000 inhabitants in the municipality of Ribeir?o Preto. The results also indicated that cysticercosis is not under control in our region since 21% of cases presented the active form of the disease. Compulsory notification proved to be a valuable resource for the epidemiologic study of cysticercosis, also permitting the mapping of more affected areas for a better direction of prevention strategies. 相似文献
35.
A de Meester C Six P Henin C Scavée R Luwaert JM Chaudron 《Canadian Metallurgical Quarterly》1996,89(12):1673-1676
The authors report the case of a 32 year old woman who was shot with a shotgun. Acute inferior wall infarction was detected fortuitously on electrocardiography and coronary angiography showed occlusion of the right coronary artery with lead shot. The single coronary lesion, absence, of other cardiac complications (haemopericardium, cardiac perforation, ...) and the favourable outcome with conservative medical treatment has not been previously reported to the authors' knowledge. 相似文献
36.
37.
O Biurrun Unzúe A Morelló Castro J Traserra Parareda 《Canadian Metallurgical Quarterly》1997,48(5):363-374
Palatopharyngeal surgery is a therapeutic option for obstructive Sleep Apnea Syndrome (OSAS). This operation is based on the assumption that the soft palate is the principal apneogenic area of the upper airways. The effectiveness of palatopharyngeal surgery and of correcting nasal obstruction (co-adjuvant factor of SAOS), when present, was evaluated. Thirty patients were selected by cephalometry for surgery (3 women, 27 men; age 45.3 +/- 7.5 years). The success rate was 60%, which justifies the inclusion of surgery as a useful option for treating SAOS. 相似文献
38.
In this study forecast of Turkey's net electricity energy consumption on sectoral basis until 2020 is explored. Artificial neural networks (ANN) is preferred as forecasting tool. The reasons behind choosing ANN are the ability of ANN to forecast future values of more than one variable at the same time and to model the nonlinear relation in the data structure. Founded forecast results by ANN are compared with official forecasts. 相似文献
39.
J. du Rouchet 《Journal of Petroleum Geology》1985,8(1):101-114
The first part of this study was published in the last issue, 7 , (4) 381–402, October 1984. The conclusion on p. 103, and references which follow, apply to both papers. 相似文献
40.
Herchang Ay JiinYuh JangJer-Nan Yeh 《International Journal of Heat and Mass Transfer》2002,45(20):4069-4078
An experimental study is performed using an infrared thermovision to monitor temperature distribution over a plate-fin surface inside the plate finned-tube heat exchangers. The differentiation of the temperature function is derived to determine the local convective heat transfer coefficients on the tested fin, using a local element lumped conduction equation included the convective effect on the boundaries with experimental data. It is disclosed that the infrared thermography is capable of rapidly detecting location and extent of transition and separation regions of the boundary layer over the whole surface of the tested models. Through the comparison of the test results on the strategy region of the in-line and staggered arrangements, it is more easy to understand or interpret the detailed dynamic phenomena of flow existed in the heat exchangers. In addition, the experimental results demonstrate that the averaged heat transfer coefficient of staggered configuration is 14-32% higher than that of in-lined configuration 相似文献