全文获取类型
收费全文 | 1871篇 |
免费 | 31篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 94篇 |
金属工艺 | 5篇 |
机械仪表 | 6篇 |
建筑科学 | 3篇 |
矿业工程 | 2篇 |
能源动力 | 7篇 |
轻工业 | 43篇 |
水利工程 | 4篇 |
无线电 | 17篇 |
一般工业技术 | 50篇 |
冶金工业 | 1637篇 |
原子能技术 | 2篇 |
自动化技术 | 26篇 |
出版年
2024年 | 3篇 |
2023年 | 2篇 |
2022年 | 12篇 |
2021年 | 28篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 17篇 |
2017年 | 18篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 25篇 |
2012年 | 15篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 48篇 |
1998年 | 422篇 |
1997年 | 253篇 |
1996年 | 198篇 |
1995年 | 83篇 |
1994年 | 93篇 |
1993年 | 116篇 |
1992年 | 15篇 |
1991年 | 26篇 |
1990年 | 28篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 30篇 |
1986年 | 39篇 |
1985年 | 24篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 21篇 |
1978年 | 5篇 |
1977年 | 53篇 |
1976年 | 113篇 |
1975年 | 4篇 |
1955年 | 2篇 |
排序方式: 共有1903条查询结果,搜索用时 0 毫秒
81.
82.
83.
84.
Patrícia Valentão Rosa M. Seabra Graciliana Lopes Luís R. Silva Vitor Martins Martha E. Trujillo Encarna Velázquez Paula B. Andrade 《Food chemistry》2007,100(1):64-70
The anthocyanin, organic acid and volatile phenol compositions of red wine obtained from Touriga Nacional grapes growing in the Dão region (Portugal) were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. By these means, nine anthocyanic compounds (malvidin-3,5-O-diglucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside, malvidin-3-O-glucoside, delphinidin, cyanidin, pelargonidin and malvidin), six organic acids (ketoglutaric, tartaric, malic, quinic, lactic and shikimic acids) and two volatile phenols (4-ethylguaiacol and 4-ethylphenol) were identified and quantified. Malvidin-3-O-glucoside, the pair lactic plus shikimic acids and 4-ethylguaiacol were the main anthocyanin, organic acids and volatile phenol, respectively. The effects of nine different Dekkera bruxellensis strains on these chemical parameters were also evaluated. The results obtained indicate that some strains of D. bruxellensis yeast are able to cause deterioration of red wine from the Dão region during its maturation by the production of volatile phenols, namely 4-ethylphenol. 相似文献
85.
86.
The method of determination of the gamma-radiation absorption distribution in microstructures of a biosystem is proposed. The absorption capacity and energy absorption distribution of some biomolecules, mass coefficients and optical density of blood and thyroid gland are calculated. Influence of the pollution of biosystem microstructures (liver, blood, thyroid, gland) by hard elements on the energy absorption distribution is demonstrated. 相似文献
87.
88.
A 9-month-old boy with a primary cystic lymphangioma of the right kidney is reported. The clinical and radiological features favored a malignant tumor. Histology revealed the lesion to be a lymphangioma; the diagnosis was confirmed by immunohistochemistry and chemical analysis of the intracystic fluid. Lymphangiomas of the kidney are rare in adults; they are even rarer in infants and children. Nevertheless, renal lymphangiomas should be considered in the differential diagnosis of multicystic, unilateral renal masses, independent of the age of the patient. 相似文献
89.
SETTING: The activity of KRM 1648 (KRM), a new benzoxazinorifamycin, and rifabutin (RBT), alone or in combination with clarithromycin (CLA), was evaluated against Mycobacterium avium complex (MAC) that multiplied in human alveolar macrophages (AM). DESIGN: AM were recovered by bronchoalveolar lavage, incubated in RPMI 1640 medium with 10% human AB serum, infected with four strains of MAC (of non-acquired immune deficiency syndrome [AIDS] origin), and then treated with each drug alone or in combination. After incubation for 7 days, colony forming units in each well were counted on 7H10 agar. RESULTS: Although concentrations between 0.2 microgram/ml and 20 micrograms/ml of both rifamycins showed clear dose-dependent activities against all MAC strains tested, only 20 micrograms/ml of each drug had modest bactericidal effect. In combination with 2.0 micrograms/ml of CLA, however, 0.2 microgram/ml of both drugs caused a bactericidal response against two of the four MAC strains examined. CONCLUSION: According to this human alveolar macrophage model of MAC infection, KRM and RBT in combination with CLA was found to be a promising candidate against human pulmonary MAC infection, and deserves clinical evaluation. 相似文献
90.