全文获取类型
收费全文 | 1207篇 |
免费 | 34篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 32篇 |
化学工业 | 126篇 |
金属工艺 | 14篇 |
机械仪表 | 24篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 24篇 |
轻工业 | 38篇 |
水利工程 | 16篇 |
石油天然气 | 3篇 |
无线电 | 57篇 |
一般工业技术 | 142篇 |
冶金工业 | 629篇 |
自动化技术 | 143篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 21篇 |
2021年 | 23篇 |
2020年 | 24篇 |
2019年 | 18篇 |
2018年 | 33篇 |
2017年 | 23篇 |
2016年 | 29篇 |
2015年 | 33篇 |
2014年 | 28篇 |
2013年 | 49篇 |
2012年 | 36篇 |
2011年 | 28篇 |
2010年 | 29篇 |
2009年 | 37篇 |
2008年 | 24篇 |
2007年 | 19篇 |
2006年 | 20篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 26篇 |
1998年 | 181篇 |
1997年 | 106篇 |
1996年 | 73篇 |
1995年 | 44篇 |
1994年 | 30篇 |
1993年 | 39篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 12篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 31篇 |
1976年 | 49篇 |
1975年 | 4篇 |
1970年 | 3篇 |
排序方式: 共有1254条查询结果,搜索用时 15 毫秒
81.
The relationship between the growth kinetics and the local chemical states of Al, Mg and O ions in ultrathin (<3 nm) oxide films grown on Al-based Al-Mg substrates at T = 300-610 K was established by ellipsometry and XPS. At T ? 385 K, an Al-oxide film of near-limiting thickness (∼1 nm) is formed, which exhibits interfacial and bulk-like states for the Al cations. At T > 385 K, continued growth is realized by the preferential oxidation of interfacially segregated Mg, resulting in the sequential appearance of interfacial and bulk-like states for the Mg cations. 相似文献
82.
83.
84.
M. Vanathi Geeta Behera Sujith Vengayil Anita Panda S. Khokhar 《Contact lens & anterior eye》2008,31(3):164-166
PURPOSE: To report a case of acute hydrops in pellucid marginal corneal degeneration (PMCD) documented with anterior segment optical segment tomography and successfully treated with sulphur hexafluoride (SF6) intracameral injection. METHODS: A 47-year-old female patient presented with spontaneous onset of pain, redness and decreased vision in her left eye. Clinical evaluation revealed bilateral PMCD with evidence of acute hydrops in the left eye. Anterior segment Slit lamp Adapted Optical Coherence Tomography (SL-OCT) examination revealed intrastromal clefts with Descemet's membrane detachment in the left eye. She was managed with descemetopexy with 0.2ml injection of iso-expansile SF6 (18%) intracameral. RESULTS: The patient showed excellent early resolution of the stromal edema with reattachment of the Descemet's membrane. CONCLUSION: Prompt intervention in acute hydrops in PMCD cases helps in achieving early good visual results and prevents potentially serious complications such as perforation. Newer imaging modalities like SL-OCT helps in better visualisation and also in monitoring the response to treatment. 相似文献
85.
A combined retrospective and prospective study of 129 beta-thalassaemia major patients seen between 1965 and 1995 in Sabah Hospital, Kuwait has been carried out. The age range at diagnosis was 2 to 84 months, median 9 months. In approximately 80 per cent, the patients were outcomes of first- or second-cousin marriages. Nine (7 per cent) of the patients were HBsAg positive, while 42 (33 per cent) were hepatitis C seropositive. Eleven (9 per cent) patients had had bone marrow transplantation (BMT). There was no BMT-related mortality, but there were three graft rejections and two cases of chronic graft-versus-host disease (GVHD). 相似文献
86.
Smita H. Panda Samir K. Naskar Paramasivan Sethuraman Sivakumar & Ramesh C. Ray 《International Journal of Food Science & Technology》2009,44(2):288-296
Sweet potato (SP) is an important root crop grown all over the world and consumed as a vegetable, boiled, baked or often fermented into food and beverages. The grated SP roots [non- boiled and fully boiled (boiled in water at 100 °C for 15 min) were treated with 0.05% of commercial pectinase enzyme (Pectinex, Novoenzyme) in order to extract the juice. The fresh juice was inoculated with Lactobacillus plantarum MTCC 1407 culture at 28 ± 2 °C for 48 h to produce lacto-juice (LJ). The anova analysis of analytical data revealed that there was significant effect of boiling conditions (fully boiled and non-boiled) on pH [ F (1, 4) = 220.5, P < 0.001), TA [ F (1, 4) = 78.89, P < 0.01], starch [ F (1, 4) = 26.63, P < 0.01), total sugar [ F (1, 4) = 61.36, P < 0.01) and anthocyanin [ F (1, 4) = 32.86, P < 0.01) but not on reducing sugar [ F (1, 4) = 2.48, P = 0.19). Sensory evaluation rated the SP LJ acceptable based on texture, taste, aroma, flavour and after taste. LJ prepared from fully boiled roots with 10% cane sugar was most preferred by a consumer's panelist based on Linear Discriminant Analysis. Principal component analyses (PCA) reduced the seven original analytical variables to three independent components (factors), which accounted for 99.9% of the total variations. Similarly, six original sensory variables were reduced to two independent components, which accounted for 65.7% of the total variations. 相似文献
87.
88.
R Marzella MA Kokkinaki M Kapsetaki A Ricco A Argyrokastritis S Kamakari T Sarafidou N Archidiacono A Roussou A Pasparaki M Rocchi NK Moschonas 《Canadian Metallurgical Quarterly》1997,79(3-4):257-265
Well-characterized, chromosome-specific somatic cell hybrid panels are powerful tools for the analysis of the human genome. We have characterized a panel of human x hamster somatic cell hybrids retaining fragments of human chromosome 10 by fluorescence in situ hybridization and associated them to genetic markers. Most of the hybrids were generated by the radiation-reduction method, starting from a chromosome 10-specific monochromosomal hybrid, whereas some were collected from hybrids retaining chromosome 10-specific fragments as a result of spontaneous in vitro rearrangements. PCR was used to score the retention of 57 microsatellite markers evenly distributed along a well-supported framework genetic map containing 149 loci uniquely placed at 69 anchor points (odds exceeding 1,000:1), with an average spacing of 2.8 cM. As an additional resource for genomic studies involving human chromosome 10, we report the cytogenetic localization of a series of YAC and PAC clones recognized by at least one genetic marker. Somatic cell hybrids provide a powerful source of partial chromosome paints useful for detailed clinical cytogenetic and primate chromosome evolution investigations. Furthermore, correlation of the above physical, genetic, and cytogenetic data contribute to an emerging consensus map of human chromosome 10. 相似文献
89.
Colon interposition is a complex operation that requires meticulous technique and attention to detail. In experienced hands, the colon is a valuable conduit for esophageal reconstruction, particularly in patients with benign disease. 相似文献
90.
Using the methods of recombination and gene disruption, the effects of degUS gene in Bacillus subtilis Ki-2-132 were studied. The results showed that the gene could affect all protease-producing, competence formation, cell mobility and repression effects of glucose on protease-production. This implies that it is a pleitropic gene in Bacillus subtilis Ki-2-132. The disruption of the gene caused morphological changes and repressed the expression of aprE in vectors. 相似文献