全文获取类型
收费全文 | 23463篇 |
免费 | 1853篇 |
国内免费 | 1247篇 |
专业分类
电工技术 | 1595篇 |
综合类 | 1745篇 |
化学工业 | 2851篇 |
金属工艺 | 980篇 |
机械仪表 | 1351篇 |
建筑科学 | 1283篇 |
矿业工程 | 558篇 |
能源动力 | 585篇 |
轻工业 | 2315篇 |
水利工程 | 454篇 |
石油天然气 | 394篇 |
武器工业 | 248篇 |
无线电 | 2319篇 |
一般工业技术 | 2462篇 |
冶金工业 | 4159篇 |
原子能技术 | 358篇 |
自动化技术 | 2906篇 |
出版年
2024年 | 88篇 |
2023年 | 266篇 |
2022年 | 582篇 |
2021年 | 751篇 |
2020年 | 541篇 |
2019年 | 419篇 |
2018年 | 445篇 |
2017年 | 507篇 |
2016年 | 460篇 |
2015年 | 726篇 |
2014年 | 869篇 |
2013年 | 1284篇 |
2012年 | 1398篇 |
2011年 | 1462篇 |
2010年 | 1461篇 |
2009年 | 1365篇 |
2008年 | 1405篇 |
2007年 | 1398篇 |
2006年 | 1167篇 |
2005年 | 1076篇 |
2004年 | 759篇 |
2003年 | 578篇 |
2002年 | 555篇 |
2001年 | 489篇 |
2000年 | 456篇 |
1999年 | 256篇 |
1998年 | 1039篇 |
1997年 | 694篇 |
1996年 | 490篇 |
1995年 | 369篇 |
1994年 | 315篇 |
1993年 | 328篇 |
1992年 | 130篇 |
1991年 | 122篇 |
1990年 | 138篇 |
1989年 | 148篇 |
1988年 | 139篇 |
1987年 | 100篇 |
1986年 | 85篇 |
1985年 | 115篇 |
1984年 | 117篇 |
1983年 | 88篇 |
1982年 | 78篇 |
1981年 | 77篇 |
1980年 | 95篇 |
1979年 | 80篇 |
1978年 | 92篇 |
1977年 | 159篇 |
1976年 | 293篇 |
1974年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
A card survey was sent to 340 veterinarians in the Urban, Delta, Highland and Coastal Plain regions of Arkansas. Veterinarians were asked to indicate numbers of dogs tested, confirmed Dirofilaria immitis positive, diagnostic techniques, frequency and period tested. A significantly greater percentage of dogs tested D. immitis positive in the Delta region as compared with the Urban region. There were no significant differences in the percentage of treated dogs on prophylaxis or the types of diagnostic tests among regions. 相似文献
12.
J. C. Jones H. Rahmati T. D. H. Do 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1992,54(4):317-318
Wood shaving samples were heated in both cubic baskets and in a previously described system realising the conditions of the ‘infinite slab’ in thermal ignition. Results from the two sets of experiment were found to be totally consistent with each other. 相似文献
13.
14.
15.
Levent Onal Sophie Cozien‐Cazuc I. Arthur Jones Christopher D. Rudd 《应用聚合物科学杂志》2008,107(6):3750-3755
The moisture uptake of polymers and composites has increasing significance where these materials are specified for invasive, long‐term medical applications. Here we analyze mass gain and the ensuing degradation mechanisms in phosphate glass fiber reinforced poly‐?‐caprolactone laminates. Specimens were manufactured using in situ polymerization of ?‐caprolactone around a bed of phosphate glass fibers. The latter were sized with 3‐aminopropyltriethoxysilane to control the rate of modulus degradation. Fiber content was the main variable in the study, and it was found that the moisture diffusion coefficient increased significantly with increasing fiber volume fraction. Diffusion, plasticization, and leaching of constituents appear to be the dominant aspects of the process over these short‐term tests. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
16.
17.
S Jones 《Canadian Metallurgical Quarterly》1997,12(12):28-31
A new method of impulse magnetic therapy was studied in the treatment of neurologic complications of osteochondrosis and deforming spondylarthrosis in 225 patients with neurologic manifestations of pathology in cervical or sacral parts of spinal column. To assess the results obtained, EMG, thermography and determination of the levels of blood plasma lipid peroxidation were used. 相似文献
18.
A new type of fiber laser modelocking is examined where a phase modulator is driven asynchronously with respect to a harmonic of the roundtrip cavity frequency. An asynchronous drive is able to produce high repetition rate (>1 GHz) soliton pulses that are shorter than the classic, active modelocking pulse width limit. It is shown that with a proper choice of fiber parameters, noise cleanup and soliton pulse shaping can be obtained using filtering and asynchronous phase modulation. Limits of asynchronous detuning are derived and a comparison with the parameters ranges for synchronous phase modulation is also presented 相似文献
19.
20.