全文获取类型
收费全文 | 1313篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 4篇 |
化学工业 | 18篇 |
金属工艺 | 3篇 |
机械仪表 | 7篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 3篇 |
水利工程 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 32篇 |
冶金工业 | 1215篇 |
原子能技术 | 5篇 |
自动化技术 | 16篇 |
出版年
2022年 | 1篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 13篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 29篇 |
1998年 | 396篇 |
1997年 | 204篇 |
1996年 | 150篇 |
1995年 | 69篇 |
1994年 | 66篇 |
1993年 | 73篇 |
1992年 | 6篇 |
1991年 | 20篇 |
1990年 | 12篇 |
1989年 | 22篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1978年 | 3篇 |
1977年 | 36篇 |
1976年 | 77篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1928年 | 1篇 |
1909年 | 1篇 |
1885年 | 4篇 |
排序方式: 共有1314条查询结果,搜索用时 15 毫秒
991.
CL DePew DL Thompson JM Fernandez LL Southern LS Sticker TL Ward 《Canadian Metallurgical Quarterly》1994,72(9):2345-2353
Concentrations of prolactin, glucose, insulin, urea N, and total amino acids in plasma of stallions after ingestion of pelleted feed were compared to those after direct gastric administration of water, NaCl, egg albumin, or corn starch (Exp. 1) or water, egg albumin, hydrolyzed casein (Amicase), or a mixture of indispensable amino acids (Exp. 2). Stallions were fed once daily (75% pellet and 25% hay) at 1500 for 30 d. On d 22, 24, 26, 28, and 30, blood samples were collected every 30 min from 1 h before through 4 h after treatment, which occurred at 1100. In Exp. 1, there was a positive secretory response for prolactin (P = .013) only after the meal. Positive glucose and insulin responses were observed after the meal (P < .055) and after gastric administration of corn starch (P < .001). Total amino acids increased (P = .008) only after the meal. In Exp. 2, a positive prolactin response (P < .001) occurred after the meal and a negative response (P = .023) after administration of water; administration of Amicase increased (P = .061) prolactin concentrations after a 2.5-h delay. Positive responses were observed for glucose, insulin, and total amino acids after the meal (P < .001) and after administration of Amicase or the amino acid mixture (P < .026). Positive urea N responses were observed after administration of Amicase and the amino acid mixture (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
992.
993.
994.
995.
996.
997.
998.
This study was designed to test the hypothesis that consumption of diets enriched in polyunsaturated fatty acids beginning at birth and continuing into young adulthood would lower the risk for atherosclerotic coronary heart disease early in life through their effects on plasma lipid and apolipoprotein concentrations while supporting good health and normal development. Accordingly, African green monkeys (n = 140) were raised on atherogenic diets (0.8 mg cholesterol per kcal) enriched with either saturated or n-6 polyunsaturated fatty acids. Breast milk from mothers fed the polyunsaturated fat diet became enriched in polyunsaturated fatty acids relative to the saturated group; thus, the period of nursing also reflected the dietary fatty acid shift. Age, gender, and dietary fat type independently affected plasma lipid and apolipoprotein concentrations. Age effects were similar for all lipid and lipoprotein variables; the concentrations were low immediately after birth, increased dramatically during the first 4-6 months of life, and then attained levels similar to those of adult animals by 2 years of age. Significant differences by gender were found such that females maintained lower total plasma cholesterol concentrations and higher high density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-I concentrations. Dietary fat effects were age dependent. Before weaning at 5 months of age, total plasma cholesterol and apoB concentrations were lower in animals consuming polyunsaturated fat, and this pattern was maintained into young adulthood. Lower concentrations of plasma triglycerides, HDL cholesterol, and apoA-I for polyunsaturated fat-fed animals were found only in the postweaning period (6-60 months of age). Since this pattern of response to dietary polyunsaturated fat in the juvenile animals was similar to that for adult animals fed these same diets in which there was less atherosclerosis and because subsequent studies have documented less coronary artery atherosclerosis in the polyunsaturated fat-fed juveniles, we conclude that early dietary intervention was beneficial in this group for lowering the risk of coronary artery atherosclerosis. The results in this primate model support the concept that intervention to modify coronary heart disease risk that is initiated early in childhood will have beneficial effects. 相似文献
999.
1000.
Intravenous inoculation of BCG was found to be both prophylactic and therapeutic in BALB/c mice against challenge with amastigotes of Leishmania donovani. Spleens and livers of mice inoculated with BCG maintained total parasite burdens at significantly lower levels when compared to controls. BCG administered intravenously 14 days prior to and on the same day of protozoan challenge was more protective than vaccine given 30 and 14 days prior to challenge. A level of 10(7) viable units of BCG provided more protection against challenge with parasites than did 10(6) viable units. BCG given the same route as the challenge dose of amastigotes provided more protection than if administered via some other route. BCG given to mice with an already established infection was shown to significantly reduce their parasite burdens. 相似文献