全文获取类型
收费全文 | 2422篇 |
免费 | 0篇 |
专业分类
化学工业 | 53篇 |
能源动力 | 1篇 |
轻工业 | 7篇 |
一般工业技术 | 14篇 |
冶金工业 | 2346篇 |
自动化技术 | 1篇 |
出版年
2021年 | 1篇 |
2017年 | 1篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 22篇 |
2010年 | 27篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2003年 | 3篇 |
1999年 | 62篇 |
1998年 | 671篇 |
1997年 | 369篇 |
1996年 | 247篇 |
1995年 | 138篇 |
1994年 | 113篇 |
1993年 | 154篇 |
1992年 | 31篇 |
1991年 | 21篇 |
1990年 | 25篇 |
1989年 | 33篇 |
1988年 | 37篇 |
1987年 | 37篇 |
1986年 | 31篇 |
1985年 | 39篇 |
1983年 | 3篇 |
1982年 | 15篇 |
1981年 | 17篇 |
1980年 | 28篇 |
1978年 | 9篇 |
1977年 | 69篇 |
1976年 | 194篇 |
1975年 | 6篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2422条查询结果,搜索用时 15 毫秒
71.
72.
LM Pote CE Couvillion RW Keirs RD Schwartz RF Taylor JH Hackathorn LK Johnson 《Canadian Metallurgical Quarterly》1992,36(3):722-724
A total of 452 broiler chickens, naturally infected with Raillietina cesticillus, were allotted into six treatment groups. One group was fed unmedicated broiler ration (Group 1), and the other five groups were fed broiler ration containing fenbendazole at 180 ppm for 3 days (38.5 mg/kg body weight [BW]), 240 ppm for 3 days (50.9 mg/kg BW), 120 ppm for 6 days (52.2 mg/kg BW), 180 ppm for 6 days (79.9 mg/kg BW), or 240 ppm for 6 days (104.3 mg/kg BW). Fenbendazole was 100.0% efficacious against R. cesticillus when administered in the diet at 240 ppm for 6 days; 99.9% at 240 ppm for 3 days and at 180 ppm for 6 days; 99.5% at 120 ppm for 6 days; and 96.9% at 180 ppm for 3 days. Fenbendazole treatment had no adverse effect on weight gain or feed intake. 相似文献
73.
RC McIntyre JH Eisenach NW Pearlman CE Ridgeway RD Liechty 《Canadian Metallurgical Quarterly》1997,174(6):750-3; discussion 753-4
BACKGROUND: The incidence of intrathyroidal parathyroid glands remains controversial. The purpose of this study was to determine the incidence in a series of patients with hyperparathyroidism. METHODS: Three hundred nine patients underwent parathyroidectomy. Patients were divided into two groups: uniglandular disease versus hyperplasia. RESULTS: Eighteen of 309 patients (6%) had abnormal intrathyroidal parathyroid glands. The incidence was 3% (7 of 222) in patients with uniglandular disease versus 15% (11 of 73) in those with hyperplasia. With a mean follow-up of 54 months, 12 patients are eucalcemic, 5 have persistent hypocalcemia, and 1 has recurrent hypercalcemia. There were no recurrent laryngeal nerve injuries. CONCLUSIONS: These data suggest that an intrathyroidal adenoma is an uncommon cause of failure, whereas abnormal intrathyroidal parathyroid tissue may be a more common cause of failure in patients with hyperplasia. 相似文献
74.
NE Huseby O Nilssen A Erfurth T Wetterling RD Kanitz 《Canadian Metallurgical Quarterly》1997,21(2):201-205
1. The effects of rilmakalim, a potassium channel opener, were studied on rabbit cardiac Purkinje, ventricular muscle and atrial fibers, with the use of conventional microelectrode techniques. 2. Rilmakalim (0.24-7.2 microM) shortened, in a concentration-dependent manner, the action potential duration (APD) in Purkinje and ventricular muscle without affecting other parameters of the action potential. Pinacidil (30-300 microM) also decreased the APD of Purkinje fibers. 3. Rilmakalim (2.4 microM) and cromakalim (100 microM) hyperpolarized and abolished abnormal automaticity of cardiac Purkinje fibers pretreated with barium (0.2-0.3 mM). Glibenclamide (5 microM) blocked the hyperpolarizing effect. 4. Stable early afterdepolarizations induced in Purkinje fibers by berberine (100 microM) were reversibly blocked by rilmakalim (2.4 microM), which also suppressed late afterdepolarizations induced in Purkinje fibers treated with ouabain (0.3-0.5 microM). 5. The rate of spontaneous discharges of the rabbit sinoatrial node was not affected by rilmakalim (7.2 microM) or by pinacidil (100 microM). Both agents were also unable to affect the APD of atrial muscle fibers. 6. In cardiac Purkinje fibers, tetraethylammonium (TEA; 20 mM) significantly reduced the effects of rilmakalim (2. 4 microM) on the APD. However, neither TEA nor glibenclamide (100 microM) reduced the shortening of the APD induced by dinitrophenol (30 microM) or by salicylate (1 mM). 相似文献
75.
76.
77.
<正>Ben Brain向大家展示如何使用黑白等调整图层将一幅普通的人像照片变得现代感十足。和很多创意产业一样,摄影行业也有属于自己的潮流。只需要看看Flickr或者印刷精美的杂志,我们就能发现流行趋势。有 相似文献
78.