全文获取类型
收费全文 | 260084篇 |
免费 | 3190篇 |
国内免费 | 823篇 |
专业分类
电工技术 | 5130篇 |
综合类 | 330篇 |
化学工业 | 37224篇 |
金属工艺 | 10252篇 |
机械仪表 | 8485篇 |
建筑科学 | 6102篇 |
矿业工程 | 1076篇 |
能源动力 | 6389篇 |
轻工业 | 22851篇 |
水利工程 | 2561篇 |
石油天然气 | 3908篇 |
武器工业 | 68篇 |
无线电 | 34720篇 |
一般工业技术 | 50060篇 |
冶金工业 | 46547篇 |
原子能技术 | 5418篇 |
自动化技术 | 22976篇 |
出版年
2021年 | 2037篇 |
2019年 | 2032篇 |
2018年 | 3467篇 |
2017年 | 3533篇 |
2016年 | 3728篇 |
2015年 | 2319篇 |
2014年 | 4047篇 |
2013年 | 11283篇 |
2012年 | 6561篇 |
2011年 | 8874篇 |
2010年 | 6981篇 |
2009年 | 7849篇 |
2008年 | 8677篇 |
2007年 | 8615篇 |
2006年 | 7802篇 |
2005年 | 7140篇 |
2004年 | 6886篇 |
2003年 | 6732篇 |
2002年 | 6371篇 |
2001年 | 6469篇 |
2000年 | 6169篇 |
1999年 | 6252篇 |
1998年 | 14248篇 |
1997年 | 10270篇 |
1996年 | 8111篇 |
1995年 | 6413篇 |
1994年 | 5712篇 |
1993年 | 5584篇 |
1992年 | 4551篇 |
1991年 | 4211篇 |
1990年 | 4048篇 |
1989年 | 3779篇 |
1988年 | 3624篇 |
1987年 | 3171篇 |
1986年 | 3065篇 |
1985年 | 3611篇 |
1984年 | 3382篇 |
1983年 | 3031篇 |
1982年 | 2850篇 |
1981年 | 2951篇 |
1980年 | 2760篇 |
1979年 | 2648篇 |
1978年 | 2499篇 |
1977年 | 2945篇 |
1976年 | 3555篇 |
1975年 | 2316篇 |
1974年 | 2312篇 |
1973年 | 2318篇 |
1972年 | 1849篇 |
1971年 | 1745篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Hamsters were fed high fiber diets containing cellulose, wheat bran or psyllium. The psyllium was incorporated into high fiber, ready-to-eat (RTE) flakes that were used to formulate the test diet. All the diets contained 0.125% cholesterol. The study was terminated after three weeks. Food intake, weight gain and feed efficiency were not significantly different in the three groups. Serum total and HDL cholesterol levels were reduced significantly by the psyllium diet. Serum triglycerides were 26% lower in the hamsters fed psyllium but because of the large variation the difference did not reach statistical significance. Liver total cholesterol and cholesteryl ester levels were significantly lower in the hamsters fed psyllium. Liver triglycerides were highest in the psyllium-fed hamsters and liver phospholipid levels were similar in the three groups. Liver cholesterol and triglyceride levels were higher in hamsters fed cellulose than in those fed wheat bran. Psyllium formulated into an RTE cereal was effective in reducing serum and liver cholesterol levels in hamsters. 相似文献
992.
993.
Ferdinand P. Ferragu O. Lechien J.L. Lescop B. Magne S. Marty V. Rougeault S. Kotrotsios G. Neuman V. Depeursinge Y. Michel J.B. Van Uffelen M. Varelas D. Berthou H. Pierre G. Renouf C. Jarret B. Verbandt Y. Stevens W. Voet M.R.H. Toscano D. 《Lightwave Technology, Journal of》1995,13(7):1303-1313
Recent developments of stability control in mines, essentially based on Ge-doped fiber Bragg gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging 相似文献
994.
2-D dopant profiling in VLSI devices using dopant-selectiveetching: an atomic force microscopy study
We report a detailed mapping of a 2-D dopant profile on a fully processed industrial sample with large dynamic range and high spatial resolution by utilizing a dopant-selective etching process and Atomic Force Microscopy. The experimental results show excellent agreement with those obtained from SRP and SIMS as corroborative methods. We also discuss the most critical factors which influence the applicability, reproducibility, and reliability of this method 相似文献
995.
MC Ocké D Kromhout A Menotti C Aravanis H Blackburn R Buzina F Fidanza A Jansen S Nedeljkovic A Nissienen 《Canadian Metallurgical Quarterly》1995,61(4):480-484
This ecologic study aimed to investigate whether differences in population mortality from lung, stomach and colorectal cancer among the 16 cohorts of the Seven Countries Study could be explained by differences in the average intake of anti-oxidant (pro)vitamins. In the 1960s, detailed dietary information was collected in small sub-samples of the cohorts by the dietary record method. In 1987, food-equivalent composites representing the average food intake of each cohort at baseline were collected locally and analyzed in a central laboratory. The vital status of all participants was verified after 25 years of follow-up. The average intake of vitamin C was strongly inversely related to the 25-year stomach-cancer mortality (r = -0.66, p = 0.01), also after adjustment for smoking and intake of salt or nitrate. The average intake of alpha-carotene, beta-carotene, and alpha-tocopherol were not independently related to mortality from lung, stomach or colorectal cancer, nor was vitamin C related to lung and colorectal cancer. 相似文献
996.
997.
998.
999.
1000.
T Rodriguez E Baumgarten R Fengler D Soumpasis G Henze 《Canadian Metallurgical Quarterly》1995,207(4):207-210
Nine children of the ALL-REZ BFM 87 and 90 trial received L-Asparginase (L-ASP) as a continuous infusion for 48-72 hs (i.e. 25 therapy cycles). Seven patients had had an allergic reaction towards an i.m. application (i.m., 29 therapy cycles). Two further patients got L-ASP initially as continuous infusion. The i.m. applications were carried out 19 times with Erwinia and 10 times with E. coli-Asparaginase, the continuous infusions 15 times with Erwinia and 10 times with E. coli-Asparaginase. In case of four patients continuous infusions of the same L-ASP type (E. coli or Erwinia) was well tolerated, after there had been an allergic reaction after i.m. application. Allergic reactions after i.m. application occurred during 10 courses as local painful erythema, during five courses as urticaria, during four courses as a general exanthema during one course as difficult breathing and during a further course as drop in blood pressure. After continuous infusion of L-ASP urticaria and difficult breathing occurred once and a transient exanthema two times. There was no anaphylactic reaction in any case. These data show that i.m. application of L-ASP causes no life-threatening side effects but allergic reactions (local pain and swelling) which clearly impaired general condition. Continuous infusion is a pharmacologically equivalent alternative with less impairment of the patients' general condition. 相似文献