全文获取类型
收费全文 | 1200篇 |
免费 | 14篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 128篇 |
金属工艺 | 22篇 |
机械仪表 | 7篇 |
建筑科学 | 17篇 |
矿业工程 | 3篇 |
能源动力 | 25篇 |
轻工业 | 29篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 108篇 |
一般工业技术 | 145篇 |
冶金工业 | 632篇 |
原子能技术 | 25篇 |
自动化技术 | 64篇 |
出版年
2023年 | 3篇 |
2022年 | 19篇 |
2021年 | 16篇 |
2020年 | 16篇 |
2019年 | 18篇 |
2018年 | 15篇 |
2017年 | 26篇 |
2016年 | 21篇 |
2015年 | 10篇 |
2014年 | 25篇 |
2013年 | 50篇 |
2012年 | 26篇 |
2011年 | 27篇 |
2010年 | 33篇 |
2009年 | 32篇 |
2008年 | 27篇 |
2007年 | 27篇 |
2006年 | 24篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 18篇 |
1998年 | 173篇 |
1997年 | 99篇 |
1996年 | 76篇 |
1995年 | 53篇 |
1994年 | 33篇 |
1993年 | 35篇 |
1992年 | 22篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 15篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 31篇 |
1976年 | 76篇 |
1975年 | 3篇 |
1955年 | 3篇 |
排序方式: 共有1218条查询结果,搜索用时 15 毫秒
1.
2.
3.
DH Kang CL Coe DO McCarthy NN Jarjour EA Kelly RR Rodriguez WW Busse 《Canadian Metallurgical Quarterly》1997,17(8):481-487
T cell cytokines play an important role in mediating airway inflammation in asthma. The predominance of a Th2 cytokine profile, particularly interleukin (IL)-4 and IL-5, is associated with the pathogenesis and course of asthma. The aim of this study was to test the hypothesis that a stressful life event alters the pattern of cytokine release in asthmatic individuals. Thirteen healthy controls and 21 asthmatic adolescents gave blood samples three times over a semester: midsemester, during the week of final examinations, and 2-3 weeks after examinations. Interferon-gamma (IFN-gamma), IL-2, IL-4, and IL-5 were measured from supernatants of cells stimulated with PHA/PMA for 24 h. Cells from asthmatic subjects released significantly more IL-5 during the examination and postexamination periods, whereas cells from healthy controls released significantly more IL-2 during the midsemester and examination periods, thereby indicating a bias for a Th2-like pattern in asthmatics and a Th1-like pattern in healthy controls. IL-4 and IL-5 production showed a marked decrease during and after examinations in healthy controls, whereas this decline was absent in asthmatics. The ratios of IFN-gamma:IL-4 and IFN-gamma:IL-5 also revealed significant changes in the profile of cytokine release across the semester. These results indicate differential cytokine responses in asthmatics that may become pronounced during periods of cellular activation. 相似文献
4.
5.
6.
NW Tomkins NN Jonsson MP Young AN Gordon KA McColl 《Canadian Metallurgical Quarterly》1997,75(10):722-723
On the basis of clinical signs and histological findings eight 9-month-old male rusa deer (Cervus timorensis) were diagnosed with sheep associated-malignant catarrhal fever. Following a variable course involving rectal temperatures around 40.5 degrees C, depression, inappetence, diarrhoea, corneal opacity and hypopyon all animals died or were euthanased over a 5-week period. Severe multifocal vasculitis, mainly periglomerular and in the arcuate vessels were consistent histological findings which in the past have been adequate to confirm clinical diagnosis of sheep associated-malignant catarrhal fever. A nested polymerase chain reaction test has been used to detect a sheep associated-malignant catarrhal fever PRC product, 238 base-pairs in size, in DNA extracted from lymphocyte preparations. The result supported the diagnosis of sheep associated-malignant catarrhal fever in these deer. 相似文献
7.
Haemangiopericytoma of nose and paranasal sinuses is relatively uncommon tumour. It occurs in adults in sixth and seventh decades of life. In view of paucity of intranasal haemangiopericytoma old in Indian literature and young age of patient, we are reporting one case in 28-year-old female who presented with recurrent, profuse epistaxis. 相似文献
8.
9.
NV Zheleznova SL Mukomolov AB Zhebrun FS Noskov II Malkova EP Shargorodskaia AD Al'tshte?n VA Pliutnikova IN Lavrent'eva NN Ptichnikova 《Canadian Metallurgical Quarterly》1996,(5):49-53
The use of a recombinant poxvirus (RPV) strain, expressing HBsAg in the process of reproduction in different bioreactor systems under stationary and bioreactor conditions of cultivation, made it possible to obtain highly purified HBsAg. The identity and purity of HBsAg was confirmed by the analysis of its amino acid composition, SDS electrophoresis in polyacrylamide gel, electron microscopy and high-performance liquid chromatography. Good prospects of the use of RPV-expressed gene engineering HBsAg as the basis vaccines against hepatitis B was demonstrated in 10 experimental batches of vaccine. All batches of the preparation had pronounced immunogenicity and were safe and nontoxic in animal experiments. The ID50 of experimental batches did not exceed 211 ng/ml, which, according to the data of comparative experiments, was lower than, or equal to, corresponding values of analogous foreign commercial preparations, based on plasma or yeast HBsAg. 相似文献
10.
NN McGihon 《Canadian Metallurgical Quarterly》1996,34(6):31-35
1. Most psychiatric and mental health professionals are experienced with writing in some form as a tool for encouraging patients to express feelings and identify stressors. 2. Narrative writing, or journal writing, can also help patients identify areas of conflict in their lives and to clarify complicated issues. 3. Writing can be used effectively with patients who are reluctant or embarrassed to speak openly in one-on-one interactions. 相似文献