全文获取类型
收费全文 | 885篇 |
免费 | 1篇 |
专业分类
化学工业 | 11篇 |
能源动力 | 2篇 |
轻工业 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 9篇 |
冶金工业 | 856篇 |
自动化技术 | 2篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2013年 | 1篇 |
2012年 | 3篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 8篇 |
1998年 | 268篇 |
1997年 | 143篇 |
1996年 | 109篇 |
1995年 | 69篇 |
1994年 | 47篇 |
1993年 | 54篇 |
1992年 | 12篇 |
1991年 | 23篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1978年 | 3篇 |
1977年 | 24篇 |
1976年 | 40篇 |
排序方式: 共有886条查询结果,搜索用时 4 毫秒
21.
The incidence of hypoplasia in children with congenital and hereditary developmental defects of the central nervous system and the locomotor system is high (44.5 +/- 3.5%), much higher than the incidence of hypoplasia in children without neurological disorders (2.0 +/- 2.0%). This is explained by exposure of the fetus and newborn to numerous intensive factors complicating the biological anamnesis because of profound disturbances of the metabolic processes and largely responsible for the underlying neurological disease and defects of hard dental tissues presenting as hypoplasia of the enamel. 相似文献
22.
IR Kamalov VA Sandrikov SV Gautier OM Tsirulnikova OG Skipenko 《Canadian Metallurgical Quarterly》1998,7(2):101-108
BACKGROUND: The distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in cytologic specimens frequently is difficult, often requiring immunocytochemistry to support the diagnosis. Recent reports have proposed the utilization of antibodies to mesothelial cell clone HBME-1 and thrombomodulin (TM), because they are immunoreactive in MM and less commonly reactive in ACA. Immunoreactivity for the monoclonal antibody CA 19-9 has been observed in many ACAs and reportedly is absent in MM. METHODS: In this study, immunostaining was performed on formalin fixed, paraffin embedded cell blocks from effusions or fine-needle aspirations using the avidin-biotin-peroxidase method. Thirty-eight MMs and 49 ACAs were tested using antibodies to CA 19-9, HBME-1, and TM. RESULTS: Anti-CA 19-9 stained only 1 of the 37 cases of MM tested (3%), but stained 24 of the 49 cases of ACA (49%). Anti-HBME-1 stained 34 of 38 cases of MM (89%), and 28 of 43 cases of ACA tested (65%). Anti-TM stained 24 of 36 cases of MM (67%), and 21 of 40 cases of ACA tested (53%). CONCLUSIONS: CA 19-9 has utility as part of an immunocytochemical panel for distinguishing ACA from MM, because a positive staining reaction would make the diagnosis of MM unlikely. Although HBME-1 and TM can identify MM positively, each frequently is detected in ACA, thus limiting the utility of these antibodies in cytologic specimens. 相似文献
23.
The interaction between mutations at the RAD2 and HIM1 genes was studied. The RAD2 gene encodes endonuclease involved in nucleotide excision repair. Mutants at this gene are highly sensitive to the lethal effect of a variety of mutagens. The product of the HIM1 gene is needed for correction of mismatched bases and repair of premutational DNA damage. Mutations in this gene lead to the formation of the mutator phenotype and high sensitivity to induced mutagenesis. The double rad2 him1 mutant manifested the synergic type of interaction. The level of UV-induced mutagenesis in the double mutant was five times higher than in single mutants, and the absolute yield of forward mutations in five genes controlling adenine biosynthesis was 1 to 2%. UV-induced mutagenesis was increased, at low doses, by several orders of magnitude in the double mutant, compared to the wild-type strain. The high level of mutagenesis in this mutant was caused by ethyl and methyl methanesulfonate. These properties of the stock with the double rad2 him1 mutation makes it promising as a tester in analysis of the gene toxicity of different substances. 相似文献
24.
25.
26.
27.
Setting up a puppy training program is one of the most important services veterinarians can offer. Puppy socialization classes aim not only to socialize the puppies so that they learn to interact well with children, adults, and other dogs, but also to teach basic obedience exercises. The classes build a strong bond between puppy, owner, and veterinary clinic. This article covers the techniques used, the structure of the classes, and outlines benefits for the dog, owner, veterinarian, and community. 相似文献
28.
29.
30.