全文获取类型
收费全文 | 3492篇 |
免费 | 16篇 |
国内免费 | 2篇 |
专业分类
化学工业 | 80篇 |
金属工艺 | 9篇 |
机械仪表 | 51篇 |
建筑科学 | 12篇 |
矿业工程 | 2篇 |
能源动力 | 9篇 |
轻工业 | 32篇 |
水利工程 | 2篇 |
无线电 | 15篇 |
一般工业技术 | 55篇 |
冶金工业 | 3196篇 |
原子能技术 | 2篇 |
自动化技术 | 45篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 29篇 |
2021年 | 23篇 |
2020年 | 14篇 |
2019年 | 27篇 |
2018年 | 19篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 19篇 |
2013年 | 20篇 |
2012年 | 14篇 |
2011年 | 16篇 |
2010年 | 9篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2000年 | 3篇 |
1999年 | 74篇 |
1998年 | 928篇 |
1997年 | 542篇 |
1996年 | 396篇 |
1995年 | 237篇 |
1994年 | 166篇 |
1993年 | 186篇 |
1992年 | 22篇 |
1991年 | 34篇 |
1990年 | 27篇 |
1989年 | 30篇 |
1988年 | 25篇 |
1987年 | 19篇 |
1986年 | 18篇 |
1985年 | 19篇 |
1983年 | 5篇 |
1982年 | 19篇 |
1981年 | 26篇 |
1980年 | 33篇 |
1979年 | 3篇 |
1978年 | 10篇 |
1977年 | 132篇 |
1976年 | 260篇 |
1975年 | 10篇 |
1964年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有3510条查询结果,搜索用时 15 毫秒
11.
12.
LV Osadchuk VV Gul'tiaeva AA Filimonenko L Jalkanen 《Canadian Metallurgical Quarterly》1996,82(5-6):102-108
15.7% of spermatozoa were found to be abnormal in silver fox males during their first reproductive season. The total number of spermatozoa and the abnormal spermatogenesis remained unchanged during mating season. Sexual stimulation increased the testosterone level only at the beginning of the mating season. 相似文献
13.
14.
15.
AA Panteleyev R Paus R Wanner W Nürnberg S Eichmüller R Thiel J Zhang BM Henz T Rosenbach 《Canadian Metallurgical Quarterly》1997,108(3):324-329
Treatment of rats with phenytoin (DPH), an anti-epileptic drug, results in lower tissue thyroid hormone (TH) levels and interferes with the metabolic pathway of TH. To test the hypothesis that DPH affects the enterohepatic cycle of TH and, thus, the kinetics of TH turnover, we performed a kinetic experiment (three-compartment analysis) and a steady-state, double-isotope equilibrium experiment in rats treated for 3 weeks with DPH (50 mg/kg body weight per day) and in untreated controls. This included measurements of TH and TH metabolite levels, as well as the activities of enzymes involved in the TH metabolic pathway. DPH treatment resulted in a decrease in the production of thyroxine (T4) (by 25%) and tri-iodothyronine (T3) (by 37%), a decrease in the T3 concentration in all three pools, and a redistribution of T4 from the fast to the slow pool. The amount of T4 increased in intestinal contents and feces by 66% and 71% respectively. Expressed as a fraction of daily TH disposal, fecal loss of T4 was enhanced from 10 to 23% and that of T3 from 16 to 21%. An increase in T4 and T3 UDP-glucuronyltransferase activities was observed, suggesting that the increased fecal loss of T4 and T3 is secondary to an increased biliary output of their glucuronides. The reduced secretion of TH and increased fecal clearance during DPH treatment can lead in the long run to depletion of TH stores. 相似文献
16.
There were 2040 patients with temporomandibular joint (TMJ) diseases in the investigation including clinical, physiological, X-ray methods of research, contrast arthrotomography, computer arthrotomography and magnetic resonance tomography. The changes of structure in different lesions were estimated. The result of received data was elaboration of classification of TMJ internal derangements with estimation of clinical forms in according with structural changes and characteristics of syndromes. 相似文献
17.
18.
19.
20.
AA Skolnick 《Canadian Metallurgical Quarterly》1998,279(11):816-817