全文获取类型
收费全文 | 5101篇 |
免费 | 43篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 26篇 |
综合类 | 2篇 |
化学工业 | 132篇 |
金属工艺 | 21篇 |
机械仪表 | 4篇 |
建筑科学 | 20篇 |
能源动力 | 23篇 |
轻工业 | 66篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 58篇 |
一般工业技术 | 80篇 |
冶金工业 | 4635篇 |
原子能技术 | 1篇 |
自动化技术 | 69篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 27篇 |
2015年 | 17篇 |
2014年 | 33篇 |
2013年 | 39篇 |
2012年 | 31篇 |
2011年 | 37篇 |
2010年 | 12篇 |
2009年 | 23篇 |
2008年 | 26篇 |
2007年 | 30篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 19篇 |
2003年 | 26篇 |
2002年 | 14篇 |
2001年 | 14篇 |
2000年 | 15篇 |
1999年 | 136篇 |
1998年 | 1433篇 |
1997年 | 883篇 |
1996年 | 500篇 |
1995年 | 279篇 |
1994年 | 262篇 |
1993年 | 286篇 |
1992年 | 40篇 |
1991年 | 55篇 |
1990年 | 78篇 |
1989年 | 64篇 |
1988年 | 73篇 |
1987年 | 70篇 |
1986年 | 49篇 |
1985年 | 37篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 16篇 |
1981年 | 31篇 |
1980年 | 45篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 97篇 |
1976年 | 209篇 |
1975年 | 5篇 |
1955年 | 3篇 |
排序方式: 共有5146条查询结果,搜索用时 31 毫秒
51.
Familial hypokalemic periodic paralysis. Clinical, diagnostic and therapeutic aspects 总被引:1,自引:0,他引:1
TP Links AJ Smit WM Molenaar MJ Zwarts HJ Oosterhuis 《Canadian Metallurgical Quarterly》1994,122(1):33-43
A model of induced lactation was modified to examine the effects of bovine prolactin (bPRL) and bovine placental lactogen (bPL) on mammary growth and differentiation. Thirty-two peripubertal, non-pregnant Holstein heifers were given daily s.c. injections of oestradiol (0.05 mg/kg) and progesterone (0.25 mg/kg) for 7 days to initiate mammary growth. Treatment with bromocriptine (40 mg/3 days) reduced serum PRL concentrations to approximately 25% of pretreatment levels, for the duration of the study. On the day following the last steroid injection, groups of eight heifers were given twice daily s.c. injections of either saline (negative control), recombinant bPRL (rbPRL; 80 mg/day) or recombinant bPL (rbPL; 80 and 160 mg/day) for 7 days. At the end of this period (day 15), growth and differentiation of the mammary glands were assessed. Treatment with rbPL increased total mammary DNA above control value by 50 and 60% for the 80 and 160 mg/day doses respectively. However, total DNA was not different for the control and rbPRL-treated groups. The blood serum concentration of alpha-lactalbumin was measured daily throughout the study and used as an index of mammary differentiation. Both rbPRL and rbPL stimulated mammary differentiation (i.e. induction of milk synthesis), although rbPRL appeared to be more potent than rbPL. These results indicate that rbPL is lactogenic in vivo and strongly suggest that bPL is a mammary mitogen. 相似文献
52.
53.
Several in vitro studies have shown that murine interleukin-5 (mIL-5) enhances IgA production by activated mucosal B cells. To date, however, there is no evidence that this factor significantly up-regulates mucosal IgA responses in vivo. Here, we show that expression of the gene for mIL-5 in a recombinant vaccinia virus vector markedly increases IgA responses to co-expressed heterologous antigen in the lungs of mice given intranasal inocula of the virus. The elevated local IgA responses to vectors expressing mIL-5 peaked at a fourfold higher level than those elicited by control virus at 14 days after infection and were sustained for at least 4 weeks. Increased IgA responses were abrogated in mice treated with monoclonal antibody against mIL-5 and were not detected in systemic lymphoid tissue. No enhancement of specific IgG levels was found either locally or systemically. Our results indicate that mIL-5 selectively enhances the development of mucosal IgA responses in vivo and suggest that expression of this factor in mucosal vaccine vectors may stimulate local immune reactivity. 相似文献
54.
55.
FV Elmslie AJ Vivian H Gardiner C Hall AP Mowat RM Winter 《Canadian Metallurgical Quarterly》1995,32(4):264-268
Alagille syndrome (AGS) is one of the major forms of chronic liver disease in childhood with severe morbidity and a mortality of 10 to 20%. It is characterised by cholestasis of variable severity with paucity of interlobular bile ducts and anomalies of the cardiovascular system, skeleton, eyes, and face. Previous studies suggest a wide variation in the expression of the disease and a high incidence of new mutations. To determine more accurately the rate of new mutations and to develop criteria for detecting the disorder in parents we systematically investigated parents in 14 families with an affected child. Clinical examination was supplemented by liver function tests, echocardiography, radiographic examination of the spine and forearm, ophthalmological assessment, and chromosome analysis. Six parents had typical anomalies in two or more systems pointing to the presence of autosomal dominant inheritance. Systematic screening of parents for the features defined in this study should improve the accuracy of genetic counselling. 相似文献
56.
57.
58.
AJ Dorta M Ferra R Bu-Colfiu L García M Gil X Escobar G Martín NA Díaz OM Perez MT Interián 《Canadian Metallurgical Quarterly》1993,10(10):490-491
It is essential to know how the immune system acts in different neurological diseases, some of them non very well known or of unknown etiology at all. It was applied Reiber and Felgenhauer's formula in 56 patients with different diseases. IgA, IgM, IgG and albumin were quantified in sera and cerebrospinal fluid by simple immunodiffusion. It was observed more frequent IgG local synthesis and IgA in this sample. 相似文献
59.
60.