全文获取类型
收费全文 | 7372篇 |
免费 | 48篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 20篇 |
综合类 | 2篇 |
化学工业 | 353篇 |
金属工艺 | 76篇 |
机械仪表 | 37篇 |
建筑科学 | 95篇 |
矿业工程 | 10篇 |
能源动力 | 31篇 |
轻工业 | 193篇 |
水利工程 | 9篇 |
石油天然气 | 24篇 |
无线电 | 244篇 |
一般工业技术 | 365篇 |
冶金工业 | 5674篇 |
原子能技术 | 17篇 |
自动化技术 | 273篇 |
出版年
2021年 | 24篇 |
2019年 | 21篇 |
2018年 | 19篇 |
2016年 | 30篇 |
2015年 | 24篇 |
2014年 | 41篇 |
2013年 | 103篇 |
2012年 | 56篇 |
2011年 | 61篇 |
2010年 | 70篇 |
2009年 | 71篇 |
2008年 | 79篇 |
2007年 | 72篇 |
2006年 | 79篇 |
2005年 | 53篇 |
2004年 | 57篇 |
2003年 | 65篇 |
2002年 | 64篇 |
2001年 | 42篇 |
2000年 | 60篇 |
1999年 | 197篇 |
1998年 | 1640篇 |
1997年 | 1014篇 |
1996年 | 602篇 |
1995年 | 337篇 |
1994年 | 341篇 |
1993年 | 364篇 |
1992年 | 86篇 |
1991年 | 100篇 |
1990年 | 138篇 |
1989年 | 104篇 |
1988年 | 126篇 |
1987年 | 118篇 |
1986年 | 89篇 |
1985年 | 67篇 |
1984年 | 38篇 |
1983年 | 51篇 |
1982年 | 46篇 |
1981年 | 53篇 |
1980年 | 89篇 |
1979年 | 39篇 |
1978年 | 40篇 |
1977年 | 125篇 |
1976年 | 269篇 |
1975年 | 37篇 |
1974年 | 14篇 |
1972年 | 19篇 |
1971年 | 14篇 |
1970年 | 21篇 |
1969年 | 12篇 |
排序方式: 共有7423条查询结果,搜索用时 31 毫秒
61.
62.
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
63.
64.
65.
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
66.
Ovarian failure is heterogeneous in etiology and may occur at various points in a woman's life. As such, it may interfere with fertility. Clinical presentation ranges from complete cessation of menses to oligomenorrhea to the continuation of menses with elevated gonadotropins. Various therapies have been used in an attempt to induce fertility, including sex steroids and gonadotropin-releasing hormone agonists to suppress circulating gonadotropin alone or in combination with estrogen or gonadotropin-releasing hormone agonists to induce ovulation. Corticosteroids are also used to overcome autoimmunity. Randomized therapeutic trials are rare and fail to demonstrate any significant improvement in ovulation and pregnancy rates. Donor oocytes have demonstrated high success rates and have proven to be useful in patients with both premature ovarian failure and natural menopause. Pregnancies have been initiated and maintained in women through 60 years of age. Thus, for those accepting of the technique, oocyte donation appears to be the treatment of choice for hypergonadotropic hypogonadism. 相似文献
67.
68.
69.
70.