全文获取类型
收费全文 | 32799篇 |
免费 | 2919篇 |
国内免费 | 1055篇 |
专业分类
电工技术 | 1333篇 |
技术理论 | 3篇 |
综合类 | 1453篇 |
化学工业 | 6507篇 |
金属工艺 | 1462篇 |
机械仪表 | 1853篇 |
建筑科学 | 2146篇 |
矿业工程 | 944篇 |
能源动力 | 1012篇 |
轻工业 | 3784篇 |
水利工程 | 536篇 |
石油天然气 | 1495篇 |
武器工业 | 158篇 |
无线电 | 3174篇 |
一般工业技术 | 4711篇 |
冶金工业 | 1755篇 |
原子能技术 | 250篇 |
自动化技术 | 4197篇 |
出版年
2024年 | 107篇 |
2023年 | 550篇 |
2022年 | 715篇 |
2021年 | 1320篇 |
2020年 | 1019篇 |
2019年 | 934篇 |
2018年 | 1126篇 |
2017年 | 1166篇 |
2016年 | 1205篇 |
2015年 | 1321篇 |
2014年 | 1730篇 |
2013年 | 2440篇 |
2012年 | 2369篇 |
2011年 | 2276篇 |
2010年 | 1924篇 |
2009年 | 1795篇 |
2008年 | 1812篇 |
2007年 | 1683篇 |
2006年 | 1610篇 |
2005年 | 1319篇 |
2004年 | 971篇 |
2003年 | 881篇 |
2002年 | 905篇 |
2001年 | 708篇 |
2000年 | 656篇 |
1999年 | 687篇 |
1998年 | 570篇 |
1997年 | 488篇 |
1996年 | 439篇 |
1995年 | 382篇 |
1994年 | 352篇 |
1993年 | 268篇 |
1992年 | 205篇 |
1991年 | 144篇 |
1990年 | 80篇 |
1989年 | 86篇 |
1988年 | 93篇 |
1987年 | 53篇 |
1986年 | 53篇 |
1985年 | 43篇 |
1984年 | 32篇 |
1983年 | 18篇 |
1982年 | 28篇 |
1981年 | 21篇 |
1980年 | 18篇 |
1979年 | 28篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 12篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
21.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage 下载免费PDF全文
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
22.
23.
24.
Rafaelle Spear Ludovic Boytard Renaud Blervaque Maggy Chwastyniak David Hot Jonathan Vanhoutte Bart Staels Yves Lemoine Nicolas Lamblin Fran?ois-René Pruvot Stephan Haulon Philippe Amouyel Florence Pinet 《International journal of molecular sciences》2015,16(5):11276-11293
Abdominal aortic aneurysm (AAA) is an inflammatory disease associated with marked changes in the cellular composition of the aortic wall. This study aims to identify microRNA (miRNA) expression in aneurysmal inflammatory cells isolated by laser microdissection from human tissue samples. The distribution of inflammatory cells (neutrophils, B and T lymphocytes, mast cells) was evaluated in human AAA biopsies. We observed in half of the samples that adventitial tertiary lymphoid organs (ATLOs) with a thickness from 0.5 to 2 mm were located exclusively in the adventitia. Out of the 850 miRNA that were screened by microarray in isolated ATLOs (n = 2), 164 miRNAs were detected in ATLOs. The three miRNAs (miR-15a-3p, miR-30a-5p and miR-489-3p) with the highest expression levels were chosen and their expression quantified by RT-PCR in isolated ATLOs (n = 4), M1 (n = 2) and M2 macrophages (n = 2) and entire aneurysmal biopsies (n = 3). Except for the miR-30a-5p, a similar modulation was found in ATLOs and the two subtypes of macrophages. The modulated miRNAs were then evaluated in the plasma of AAA patients for their potential as AAA biomarkers. Our data emphasize the potential of miR-15a-3p and miR-30a-5p as biomarkers of AAA but also as triggers of ATLO evolution. Further investigations will be required to evaluate their targets in order to better understand AAA pathophysiology. 相似文献
25.
26.
Yao‐Min Hung Neng‐Chyan Huang Jyh‐Seng Wang Shue‐Ren Wann 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(2):344-346
Cases of isolated hepatic tuberculosis (TB) are rare. The diagnosis is often delayed or missed because of nonspecific symptoms and laboratory findings. Besides, the disease is extremely rare even in a country where TB is an alarming public health problem. This report demonstrates the difficulty in correctly diagnosing local hepatic TB. We report the case of a 62‐year‐old male patient with end‐stage renal disease treated with hemodialysis, who developed 2 months of abdominal distension and general anorexia, with hyperechoic hepatic lesions on ultrasound. Computed tomography suspected multiple liver tumors. The liver biopsy finally led to the diagnosis of TB of the liver without other involvements. We conclude that isolated hepatic TB is one of the rare forms of extrapulmonary TB in dialysis patients. A greater awareness of this rare clinical entity may prevent needless surgical interventions. 相似文献
27.
28.
29.
30.
Lei He Yan Xuan Feng Zhang Xue Wang Huaqing Pan Junfeng Ren Meina Chen 《International Journal of Hydrogen Energy》2021,46(1):1096-1105
Bulk and surface properties of proton stability and transportation in Y and Nd co-doped BaCeO3 (BCYN), especially the effect of Nd segregation, were investigated by first-principles calculations. Since the structure of doped BaCeO3 at the operating temperature of proton-conducting has been unclear for a long time, we have summarized the latest experimental results and calculated the structure of the asymmetric BCYN for the first time. The results show that compared with Y, Nd doping promotes oxygen vacancy formation, however reduces proton stability. Our calculation can also provide a possible explanation for the formation of space charge layer at the grain boundary of doped BaCeO3 in experiment. Unlike the stable Y in BCYN, Nd is calculated to be easily segregated, which can facilitate both proton hydration and proton transportation near the surface. Moreover, Nd segregation at the grain boundary is predicted to be beneficial for proton transportation between grains. 相似文献