全文获取类型
收费全文 | 1128篇 |
免费 | 23篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 113篇 |
综合类 | 1篇 |
化学工业 | 428篇 |
金属工艺 | 14篇 |
机械仪表 | 19篇 |
建筑科学 | 18篇 |
能源动力 | 44篇 |
轻工业 | 96篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 55篇 |
一般工业技术 | 184篇 |
冶金工业 | 76篇 |
原子能技术 | 32篇 |
自动化技术 | 70篇 |
出版年
2022年 | 5篇 |
2021年 | 28篇 |
2020年 | 13篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 49篇 |
2012年 | 48篇 |
2011年 | 48篇 |
2010年 | 43篇 |
2009年 | 40篇 |
2008年 | 55篇 |
2007年 | 59篇 |
2006年 | 39篇 |
2005年 | 37篇 |
2004年 | 31篇 |
2003年 | 32篇 |
2002年 | 32篇 |
2001年 | 22篇 |
2000年 | 18篇 |
1999年 | 23篇 |
1998年 | 51篇 |
1997年 | 35篇 |
1996年 | 35篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1993年 | 22篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 16篇 |
1984年 | 9篇 |
1983年 | 19篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 15篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 7篇 |
排序方式: 共有1152条查询结果,搜索用时 218 毫秒
1.
2.
3.
4.
5.
Hideaki Katayama Tsutomu Tawa Shinzaburo Ito Masahide Yamamoto Yoshio Wada 《Polymer Bulletin》1992,29(3-4):365-367
Summary The effect of side chain length on intramolecular triplet energy migration of naphthalene containing polymers was investigated by a delayed fluorescence (DF) spectroscopy for the solid solution of the polymers. The degree of triplet energy migration depends strongly on whether the chromophores are directly attached to the main chain or not. 相似文献
6.
Bhupesh C. Roy Motonobu Goto & Tsutomu Hirose 《International Journal of Food Science & Technology》1996,31(2):137-141
Tomato seed oil was extracted with supercritical carbon dioxide in a semibatch-flow extractor within the temperature range 313–343 K and the pressure range 10.8–24.5MPa. The extraction rates increased with pressure, but decreased with temperature increase because of the variation in solvent density and resultant differences in oil solubility. The fatty acid composition of the extracted oil was similar to that of soybean oil. 相似文献
7.
I Hirata S Kimura T Michihata H Osawa M Kume T Kashima 《Canadian Metallurgical Quarterly》1997,45(8):1173-1177
A 66-year-old male with Beh?et's disease admitted again with hemoptysis. He underwent the resection and direct closure of descending aortic aneurysm 3 years ago, followed without the use of steroid. Chest CT scanning demonstrated a recurrent aneurysm of the descending aorta which was could not be detected on the previous CT only 23 days before. In the current operation, we performed resection, direct closure and wrapping of the aneurysm. The pathological examination showed a true aneurysm of Beh?et's disease. The patient is free from recurrence for 17 months since the operation under steroid therapy. 相似文献
8.
S Kwon RA Hess D Bunick H Nitta L Janulis Y Osawa JM Bahr 《Canadian Metallurgical Quarterly》1995,53(6):1259-1264
We recently found that cytochrome P450 aromatase (P450arom) is present in germ cells of the mammalian testis and is capable of converting androgens to estrogens in the male reproductive tract. The objective of the present study was to determine whether testicular germ cells and epididymal sperm of an avian species are also capable of synthesizing estrogen. P450arom was localized in the rooster testis and epididymal region by immunocytochemistry, using an antiserum generated against purified human placental cytochrome P450arom. Immunostaining was present in pachytene spermatocytes, round spermatids, elongated spermatids, flagella of late spermatids, and sperm in the epididymal region. A positive reaction was also found in nonciliated cells of the epididymal region. However, the absence of mRNA for P450arom in the epididymal region indicated that the immunoreactive protein present in the epididymal region is not synthesized in this region. The immunoreactive P450arom found in epididymal sperm was shown to be active through use of a 3H2O assay. On the basis of these data, we conclude that rooster testicular germ cells and epididymal sperm are sites for the synthesis of estrogen, a potential regulator or modulator of germinal epithelium in the testis and the epithelium of the epididymal region of the avian species. 相似文献
9.
In order to investigate the influence of puffer volume V/sub P/ and operating force to dielectric performance of GCB at current interruption, we calculated the prospective dielectric withstand voltage V/sub W/ between arcing contacts. The withstand voltage was calculated by the electric field strength appeared on arcing contacts and the allowable electric field strength E/sub W//sup */ of hot gas due to thermal puffer action. We could clarify that large initial puffer volume V/sub P/ can increase withstand voltage V/sub W/ at current breaking point and also that an optimum point exists in operating force F. For example, it was found that in case of the operating force of 1000 kgf, the puffer volume V/sub P/ of 1.2 liter would be best choice in the interrupting condition of i=50 kA and arcing time of 1.35 cycle. 相似文献
10.
K Uchida OT Khor T Oya T Osawa Y Yasuda T Miyata 《Canadian Metallurgical Quarterly》1997,410(2-3):313-318
Methylglyoxal (MG), an endogenous metabolite that increases in diabetes, is a common intermediate in nonenzymatic glycation (Maillard reaction) in vivo. Here we describe the immunochemical approach to the detection of MG adducts in proteins in vitro and in atherosclerotic lesions of human aorta in vivo. The reaction of protein (bovine serum albumin) with MG led to selective loss of arginine and lysine residues, accompanied by the formation of 5-methylimidazolone (N delta-(5-methylimidazolon-2-yl)ornithine) and imidazolysine (1,3-di-lysino-4-methylimidazole) derivatives, respectively. The anti-5-methylimidazolone antibody was prepared by immunizing rabbits with a MG-keyhole limpet hemocyanin conjugate and purifying the serum on an affinity gel prepared by covalent attachment of the 5-methylimidazolone derivative. The antibody cross-reacted with the proteins treated with not only MG but trioses, such as hydroxyacetone, dihydroxyacetone, and glyceraldehyde. The immunohistochemical analysis revealed that atherosclerotic lesions of human aorta contained 5-methylimidazolone derivatives whose distributions were identical to those of advanced glycation end products (AGEs) detected by the anti-AGE antibody. 相似文献