全文获取类型
收费全文 | 1320篇 |
免费 | 28篇 |
国内免费 | 32篇 |
专业分类
电工技术 | 31篇 |
综合类 | 43篇 |
化学工业 | 154篇 |
金属工艺 | 39篇 |
机械仪表 | 42篇 |
建筑科学 | 76篇 |
矿业工程 | 3篇 |
能源动力 | 8篇 |
轻工业 | 82篇 |
水利工程 | 15篇 |
石油天然气 | 16篇 |
武器工业 | 2篇 |
无线电 | 37篇 |
一般工业技术 | 34篇 |
冶金工业 | 727篇 |
原子能技术 | 2篇 |
自动化技术 | 69篇 |
出版年
2022年 | 3篇 |
2021年 | 8篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2015年 | 23篇 |
2014年 | 70篇 |
2013年 | 53篇 |
2012年 | 30篇 |
2011年 | 102篇 |
2010年 | 27篇 |
2009年 | 58篇 |
2008年 | 33篇 |
2007年 | 39篇 |
2006年 | 34篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 12篇 |
2000年 | 6篇 |
1999年 | 20篇 |
1998年 | 213篇 |
1997年 | 123篇 |
1996年 | 83篇 |
1995年 | 61篇 |
1994年 | 36篇 |
1993年 | 44篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 26篇 |
1976年 | 42篇 |
1975年 | 6篇 |
1973年 | 4篇 |
1971年 | 3篇 |
1969年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有1380条查询结果,搜索用时 15 毫秒
1.
NI Koval'chuk FN Shubin VA Khoroshko FN Sheverdina TT Tarasenko NG Kosheleva 《Canadian Metallurgical Quarterly》1997,(5):88-91
The results of the comparative study of the phenotypical properties and the plasmid profile of 63 strains of salmonellae, belonging to 44 serotypes of groups B, C1, C2, C3, D, E1, E4, F. The study revealed that strains of different serotypes had their individual plasmid profile. Strains of the same serotype of salmonellae isolated from similar sources had an identical plasmid profile, while strains isolated from different sources differed in their plasmid profiles, though they might have a similar phenotype. Plasmid analysis was shown to be an effective method for the intraspecific typing of rarely isolated Salmonella serotypes and suitable for use as the basis of the microbiological monitoring of salmonellae. 相似文献
2.
3.
NG Darenskaia AO Korotkevich SS Kuznetsova TA Nasonova 《Canadian Metallurgical Quarterly》1997,37(3):423-430
Radiation sickness manifestations have been studied in dogs exposed to electrons (electron energy 25 MeV) and gamma-neutron radiation (neutron energies of 0.37 and 1.2 MeV) in a wide dose range. Dose-response relationships have been calculated for mortality and some clinical manifestations of the intestinal and cerebral forms of radiation sickness. With regard to mortality, the highest effect has been observed for gamma-neutron radiation with a neutron energy of 1.2 MeV. For equal physical doses and for those equally effective in relation to mortality, clinical manifestations of damage are more prominent following exposure to electrons. 相似文献
4.
The partition of free fatty acids (FFA) to egg-phosphatidylcholine (egg-PC) and egg-phosphatidylethanolamine (egg-PE) vesicles was studied. Upon the addition of FFA to the suspension of vesicles, the pH of the aqueous phase changed depending on the length and saturation of the FFA hydrocarbon chain, as well as on the vesicle composition. The medium pH decreased faster if FFA was added to egg-PE as compared to egg-PC vesicles. The fluorescent free fatty acid indicator (ADIFAB) was used to measure the amount of FFA remaining in the aqueous phase. Most of the FFA added to the suspension of egg-PE vesicles remained in the aqueous phase, whereas in the presence of egg-PC vesicles the FFA partitioned preferentially into the lipid phase. The amount of FFA incorporated into the lipid bilayers was estimated by measuring the changes of pH at the lipid bilayer surface, using fluorescein-PE. At high surface concentrations of FFA, decreasing pH at the bilayer surface caused the protonation of FFA, and raised the pK of FFA at the bilayer surface from 5 to about 7. The partition of FFA in egg-PE vesicles was an order of magnitude lower than that in egg-PC vesicles. The incorporation amount was determined more by the molecular packing than by the nature of lipid headgroups, because steroylcaprioyl-PE, which preferred the bilayer structure, behaved more like egg-PC than egg-PE. Understanding FFA partition characteristics would help to interpret the hydrolysis measurements of phospholipids, and to explain many biological activities of FFA. 相似文献
5.
6.
Case-control methodology was used to assess lung cancer risk from exposure to arsenic in air, employing data from former workers in different units at the Chuquicamata copper mine and smelter complex. Thirty two workers from this complex were identified among the lung cancer deaths that occurred in the Northern region of Chile between 1987 and 1991. Each case was matched on age and sex, with controls that had a similar date of enrolment in the company. Available data on arsenic concentrations in air for six work sites were compiled from 1952 to 1991 and these were used to categorize the workplaces: Administrative area (1.6 micrograms/m3), Mine (2.3 micrograms/m3), Oxid Plant (3.1 micrograms/m3), Workshop and Services (9.8 micrograms/m3), Sulphur Plant (8.4 micrograms/m3) and Smelter (201.7 micrograms/m3). The results indicate an Odds Ratio of 5.7 (Fisher's p = 0.016) of dying from lung cancer among workers of the smelter compared with the rest of the workers. 相似文献
7.
8.
9.
10.
The exposure to paired electric impulses and vibromassage promotes completeness of repair in the treatment of injured peripheral nerves of the limb. The effect is achieved due to marked stimulation of myelinization and differentiation of the nerve fibers, regeneration of the nerve system in the denervated muscle. 相似文献