全文获取类型
收费全文 | 4591篇 |
免费 | 4篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 51篇 |
金属工艺 | 1篇 |
机械仪表 | 11篇 |
建筑科学 | 12篇 |
能源动力 | 3篇 |
轻工业 | 32篇 |
水利工程 | 1篇 |
无线电 | 29篇 |
一般工业技术 | 99篇 |
冶金工业 | 4284篇 |
自动化技术 | 70篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 21篇 |
2012年 | 16篇 |
2011年 | 20篇 |
2010年 | 7篇 |
2009年 | 12篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 16篇 |
2005年 | 20篇 |
2004年 | 10篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 142篇 |
1998年 | 1440篇 |
1997年 | 797篇 |
1996年 | 530篇 |
1995年 | 267篇 |
1994年 | 238篇 |
1993年 | 255篇 |
1992年 | 32篇 |
1991年 | 44篇 |
1990年 | 37篇 |
1989年 | 51篇 |
1988年 | 51篇 |
1987年 | 30篇 |
1986年 | 27篇 |
1985年 | 29篇 |
1984年 | 4篇 |
1983年 | 13篇 |
1982年 | 13篇 |
1981年 | 21篇 |
1980年 | 37篇 |
1978年 | 6篇 |
1977年 | 85篇 |
1976年 | 195篇 |
1975年 | 8篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有4595条查询结果,搜索用时 68 毫秒
11.
A key theme in safety is the investigation and improvement of work processes and conditions. This is built on a tradition of studying accidents, but there is growing interest in the investigation of everyday work. Researchers have started using terms such as success, normal and everyday work investigations, but behind these can be different activities. This paper makes explicit some considerations behind investigations of everyday work, how these considerations shape an investigation, and how they reflect different schools of thought. These considerations can be used as an aid for designing everyday work investigations for safety and serve as a first step towards critical reflection on investigating everyday work. 相似文献
12.
A 54-year-old woman developed pain, tenderness, and swelling at the site where a short acupuncture needle had been placed in the helix of the pinna. Staphylococcus aureus was isolated from this LESION. Which was treated with removal of the needle and intravenously administered nafcillin. The patient recovered completely and had no scarring. 相似文献
13.
The use of photodynamic dye and light inactivation for the treatment of genital herpes simplex virus infections has been associated with the risk of potential oncogenesis. Sixteen patients treated with neutral red and fluorescent light for documented herpetic infections were studied at intervals ranging from 9 to 52 months following treatment. Four patients treated with other modalities were included in the study. Biopsies of the treated areas were obtained, and 3925 tissue sections were examined. Mild atypical epithelial changes were focally present in most specimens regardless of therapy. Histologically identifiable premalignant change could not be demonstrated. 相似文献
14.
The frequency and severity of CNSLD was studied in workers of an Hungarian firm (Ganz-Mavag) by means of questionnaire. Symptoms of CNSLD can be found more frequently in workers with air pollution than in those without. The symptoms of CNSLD show an age-dependence with regard to frequency and grade of severity, the single symptoms of CNSLD not occurring simultaneously and changing in their proportional frequency. 相似文献
15.
16.
17.
Halofenate, a serum lipid-lowering agent which inhibits binding of thyroid hormone to thyroxine-binding globulin (TBG), was administered daily for 14 days to 8 hypothyroid subjects with elevated TSH concentrations as a result of incomplete thyroxine (T4) therapy. Drug administration resulted in mean increases in serum dialyzable fraction T4 (DFT4) of 52% over pretreatment levels (P less than 0.01) and in dialyzable fraction triiodothyronine (DFT3) of 26% in 7 subjects, (P less than 0.01). During halofenate treatment in these 7 subjects, serum TSH concentrations decreased significantly (mean = 39%, P less than 0.01) when DFT4 and DFT3 were increased by halofenate. In only two subjects was there a convincing temporal relationship between increased serum absolute free T4 (AFT4) and decreased serum TSH concentrations. Contrary to what would be predicted from the "free hormone hypothesis", changes in serum TSH concentration in these hypothyroid patients appeared to relate primarily to changes in the free fraction of circulating T4 and T3 (DFT4, DFT3), rather than to alterations in AFT4 or AFT3. Halofenate did not alter serum TBG binding capacity. An eighth subject did not show increased DFT4 and DFT3 during halofenate treatment despite achievement of therapeutic serum levels of the agent; in this patient, serum TSH levels rose progressively throughout the period of inadequate T4 replacement and halofenate administration. In hypothyroid patients, short-term halofenate use suggests that the pituitary-thyroid hormone feedback circuit can respond to increases in serum DFT4 and DFT3 in the absence of detactable increases in absolute free hormone concentrations. 相似文献
18.
19.
A trial of a continuous intravenous infusion of Althesin is described for sedation during cardiac catheterisation, both for children and adults. The conditions produced for the procedure were very satisfactory. The advantages and problems of its use are discussed. The technique justifies further trials. 相似文献
20.
Stereochemical requirements for intercalation of platinum complexes into double-stranded DNA's 总被引:1,自引:0,他引:1
The complexes 1,10-phenanthrolineethylenediamineplatinum(II) and 2,2'-bipyridineethylenediamineplatinum(II) have a planar, aromatic ligand system that facilitates intercalation, as shown by their ability to unwind closed circular duplex DNA. Nonbonded steric interactions can rotate the pryidine ligands out of the coordination plane in bis(pyridine)ethylenediamineplatinum(II), thus preventing intercalation. Fiber x-ray diffraction patterns of the two metallointeracalators indicate that the binding is governed by the neighbor exclusion principle. 相似文献