全文获取类型
收费全文 | 771篇 |
免费 | 4篇 |
专业分类
化学工业 | 24篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 12篇 |
水利工程 | 4篇 |
无线电 | 19篇 |
一般工业技术 | 19篇 |
冶金工业 | 676篇 |
原子能技术 | 2篇 |
自动化技术 | 8篇 |
出版年
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 19篇 |
1998年 | 183篇 |
1997年 | 116篇 |
1996年 | 75篇 |
1995年 | 57篇 |
1994年 | 32篇 |
1993年 | 39篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1978年 | 1篇 |
1977年 | 22篇 |
1976年 | 65篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有775条查询结果,搜索用时 0 毫秒
761.
SN Skopinskaia ID Riabova IV Galushchenko EP Severina VL Boroviagin 《Canadian Metallurgical Quarterly》1976,41(10):1791-1797
A comparative study of ultrastructure and IR-spectroscopy of osmotic shock membranes from cells of glycolyzing (Streptococcus faecalis) and respiring (Micrococcus lysodeikticus) bacteria, was made. The S. faecalis and M. lysodeikticus membranes differ in their cross-section. Treatment of the preliminary washed membranes of S. faecalis and M. lysodeikticus with a low ionic strength solution removes 40% and 70% of their proteins respectively, decreases the membrane cross-section but does not change their fracture faces. Pre-cooling of the membrane suspensions within the temperature range of +5 degrees-10 degrees results in the appearance of large smooth areas on S. faecalis membrane fracture faces, but does not affect the ones of M. lysodeikticus membrane. Treatment of the washed suspensions with Triton X-100 results in the appearance of drastic changes of S. faecalis membrane fracture faces and does not change the fracture faces of M. lysodeikticus membranes; treatment by the detergent does not alter the IR-spectroscopy of membranes of both bacteria. Treatment of S. faecalis and M. lysodeikticus membranes with high temperature irreversibly changes the structure of 20% and 40% of protein components respectively,, but does not affect the distribution of the subparticles on their fracture faces. It is assumed that the differences found are determined by the composition of lipid components of the membranes studied and that the amount of proteins closely bound with lipids in the membranes of S. faecalis is likely to be greater than that of M. lysodeikticus membranes. 相似文献
762.
VV Men''shikov VL Cherkasov AF Bunamian NK Iakhontova 《Canadian Metallurgical Quarterly》1976,54(6):95-100
Deep neck infection has ominous implications if not detected and treated in an early stage. The anatomic relationships of head and neck spaces encourage spread of infection. Immediate hospitalization and constant monitoring of the patient after diagnosis are mandatory. 相似文献
763.
With the aid of a polygraphical study of day sleep in infants with cerebral palsy it was possible to demonstrate in many cases changes of qualitative characteristics of the stages of sleep with disorders of normal dynamics in the EEG, motor and vegetative signs. The authors detected a certain correlation between the degree of such changes and the severity of the clinical symptomatology, as well as a possibility of changes in expression of the pathology of sleep at different stages of the disease, sometimes with an increase of this pathology. 相似文献
764.
Studies have been made on thermal denaturation of rhodopsin in hotoreceptive membranes of retinal rods of some Japan Sea fishes--Podthecus sp., Enophrys diceraus, Myoxocephalus stelleri, Pleurogrammus monopterygius, Sebastichthys trivittatus, Pheumatophorus japonicus, Gadus morhua, Theragia chaloogramma, Eleginus gracilis and Lepidopsetta herzensteini. It was shown that visual pigments of the species studied significantly differ in their thermostability, whereas with respect to their spectral properties they are rather similar (absorbtion maxima lie near 500 nm). Positive correlation between the thermostability level of rhodopsins and the environmental temperature of the species was found. 相似文献
765.
766.
767.
768.
769.
770.
Medical research studies utilize survey instruments consisting of responses to multiple items combined into one or more scales. These studies can benefit from methods for evaluating those scales. Such an approach is presented for evaluating exploratory and confirmatory factor analysis models with decisions about covariance structure, including the number of factors, the factor extraction procedure, the allocation of survey items to summated scales and the extent of inter-scale dependence, made objectively using a likelihood-based form of cross-validation. This approach is demonstrated through example analyses using baseline data for three survey instruments from a clinical trial involving adolescents with type 1 diabetes. 相似文献