全文获取类型
收费全文 | 9414篇 |
免费 | 643篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 126篇 |
综合类 | 5篇 |
化学工业 | 2267篇 |
金属工艺 | 150篇 |
机械仪表 | 318篇 |
建筑科学 | 365篇 |
矿业工程 | 18篇 |
能源动力 | 408篇 |
轻工业 | 1802篇 |
水利工程 | 129篇 |
石油天然气 | 58篇 |
武器工业 | 2篇 |
无线电 | 504篇 |
一般工业技术 | 1438篇 |
冶金工业 | 855篇 |
原子能技术 | 72篇 |
自动化技术 | 1552篇 |
出版年
2024年 | 25篇 |
2023年 | 94篇 |
2022年 | 137篇 |
2021年 | 442篇 |
2020年 | 294篇 |
2019年 | 319篇 |
2018年 | 391篇 |
2017年 | 408篇 |
2016年 | 445篇 |
2015年 | 295篇 |
2014年 | 405篇 |
2013年 | 753篇 |
2012年 | 647篇 |
2011年 | 774篇 |
2010年 | 522篇 |
2009年 | 543篇 |
2008年 | 486篇 |
2007年 | 385篇 |
2006年 | 319篇 |
2005年 | 243篇 |
2004年 | 191篇 |
2003年 | 185篇 |
2002年 | 167篇 |
2001年 | 115篇 |
2000年 | 118篇 |
1999年 | 113篇 |
1998年 | 304篇 |
1997年 | 215篇 |
1996年 | 142篇 |
1995年 | 99篇 |
1994年 | 61篇 |
1993年 | 60篇 |
1992年 | 29篇 |
1991年 | 20篇 |
1990年 | 27篇 |
1989年 | 29篇 |
1988年 | 21篇 |
1987年 | 14篇 |
1986年 | 17篇 |
1985年 | 20篇 |
1984年 | 24篇 |
1983年 | 28篇 |
1982年 | 15篇 |
1981年 | 19篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 18篇 |
1976年 | 24篇 |
1975年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
JF Tomás E Rodriguez-I?igo J Bartolomé A Madejón M Fogeda H Oliva A Moreno JM Fernández-Ra?ada V Carre?o 《Canadian Metallurgical Quarterly》1997,19(10):1053-1057
Long-term effects after blood or bone marrow transplantation (BMT) are emerging as an important issue, as more patients are included in BMT programmes and as this procedure becomes more successful. Long-term liver dysfunction, mainly due to chronic graft-versus-host disease or hepatitis C virus infection, is a well-known complication. Nevertheless, the diagnosis of liver disease in this patient group is sometimes difficult and, despite adequate studies, it may remain undetected. A novel hepatitis-associated virus, hepatitis G virus (HGV), has recently been identified. The virus belongs to the Flaviviridae family and is known to be parenterally transmitted, although there is no clear evidence to implicate this agent in causing acute or chronic hepatitis. We report a patient who developed mild, but persistent, abnormalities in transaminases for 2 years after an autologous BMT. HGV RNA was detected in both serum and liver. HGV RNA persisted in serum for at least 8 months. No other known hepatitis virus was found. This report provides the first direct evidence of a patient with long-term liver abnormalities after a BMT in whom the only known hepatitis virus isolated was the HGV. 相似文献
62.
The article presents a review of most important research results as well as opinions about the role and importance of body image disturbances in the development and the course of eating disorders. It also contains a review of definitions of body image, and techniques used in the evaluation of this type of disorders. 相似文献
63.
64.
Rodrigo Brquez Mario Espinoza Rodrigo Ormeo 《Journal of the science of food and agriculture》1994,66(2):181-186
Total volatile basic nitrogen (TVB-N) as a measure of protein degradation and total microbial counts or stored raw mackerel (Trachurus murphy), which had been treated with chemical preservatives, were compared with the TVB-N and microbial counts of untreated fish. In unpreserved fish, decomposition of fish protein was rapid. Treatment of mackerel with acetic (1000-5000 μg kg?1), which was the most effective of the parameters studied, approximately halved the rate of increase in TVB-N compared with the untreated samples. Changes in the total microbial counts presented a similar trend. 相似文献
65.
66.
The first part of this paper analyses the influence of the molecular weight and concentration of carboxymethyl cellulose (CMC) and of kaolin concentration on rheology of the coating colours and on paper properties coated with ultra lightweight coatings (ULWC). In the second part, relationships between the rheological characteristics of the coating colour formulations and coated paper surface quality was also studied.New indexes on paper roughness at micro-scale are presented (RZI and SRI). In general, they show good correlation with sheet gloss. A new gloss index (SGI) is presented, accounting for the contribution of gloss from machine direction (MD) and cross direction (CD). Porosimetry was used to access microstructural characteristics in order to correlate them with light scattering and gloss properties. The former property is closely related to Hg intrusion volume of the coated layer while gloss is related to surface porosity with pore diameters in the range of 7–15 μm as measured by Hg intrusion volume. 相似文献
67.
Jos A.D. Muoz Antn Alvarez Jorge Ancheyta Miguel A. Rodríguez Gustavo Marroquín 《Catalysis Today》2005,109(1-4):214-218
The present paper focuses on the study of process alternatives for heat integration of a heavy crude oil hydrotreatment plant. Experimental information obtained from a pilot scale, kinetics and reactor modeling tools, and a commercial process simulator were employed to develop mass and energy balances. Four study cases, which employ a combination of quenching and heat exchangers, were identified and evaluated. The results indicated that the case with two quenches with hydrogen and three heat exchangers is the best process heat integration (PHI) option from an energetic point of view. 相似文献
68.
69.
70.
We compute the temperature dependent magnetic susceptibility of the single-impurity, two-channel Anderson model with an alternative multi-step numerical renormalization-group transformation, previously applied only to the two-impurity single-channel Kondo model. Compared with the traditional transformation, the new procedure requires substantially less memory and computational time, and opens therefore perspectives for the application of the numerical renormalization-group procedure to more complex Hamiltonians. 相似文献