全文获取类型
收费全文 | 3883篇 |
免费 | 3篇 |
专业分类
化学工业 | 20篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 1篇 |
轻工业 | 1篇 |
石油天然气 | 2篇 |
一般工业技术 | 2篇 |
冶金工业 | 3853篇 |
自动化技术 | 4篇 |
出版年
2020年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 107篇 |
1998年 | 1152篇 |
1997年 | 698篇 |
1996年 | 448篇 |
1995年 | 219篇 |
1994年 | 222篇 |
1993年 | 212篇 |
1992年 | 17篇 |
1991年 | 44篇 |
1990年 | 36篇 |
1989年 | 42篇 |
1988年 | 33篇 |
1987年 | 41篇 |
1986年 | 52篇 |
1985年 | 34篇 |
1984年 | 1篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 25篇 |
1980年 | 50篇 |
1979年 | 3篇 |
1978年 | 9篇 |
1977年 | 110篇 |
1976年 | 258篇 |
1975年 | 7篇 |
1964年 | 1篇 |
1955年 | 5篇 |
1954年 | 2篇 |
排序方式: 共有3886条查询结果,搜索用时 0 毫秒
61.
62.
A Donnet H Dufour D Gambarelli N Bruder JF Pellissier F Grisoli 《Canadian Metallurgical Quarterly》1996,152(12):748-751
The clinical and pathological findings of a 43-year-old woman, diagnosed as having acute hemorrhagic leukoencephalitis at postmortem examination, are presented. The acute hemorrhagic leukoencephalitis affects mainly young adults and is the most fulminant from of demyelinating disease. It is frequently preceded by a respiratory infection. Diagnosis is facilitated by CT scanning and MRI, which reveal the massive lesion in the cerebral white matter. Many cases terminate fatally in 2 or 4 days, but in others survival is longer. The pathological findings are distinctive. 相似文献
63.
64.
65.
Following a survey in 19 European countries of the habits, attitudes and knowledge of medical students regarding tobacco, World Health Organisation European Office and the International Union against Tuberculosis and Lung Disease jointly circulated to the Deans of all European medical schools a summary of the results, including figures for mortality for smoking-related diseases in their countries and a brief questionnaire concerning faculty action on the tobacco problem. The response rate was just over 50%, higher in Northern Europe (66%) than in Southern (35%) or Eastern (38%). Only 8% of faculties had a specific teaching module on tobacco. In most it was either systematically (35%) or unsystematically (55%) integrated in other teaching. Teaching hospitals, teaching areas and faculty meetings were said to be smokefree by over 90%; figures were lower for other areas. Seventy-seven per cent of Deans intended to discuss our approach with their teaching staff; 72% gave the name of a staff member with a particular tobacco interest. 相似文献
66.
The in vitro activities of the N,N-dimethylglycyl-amino derivative of minocycline (DMG-MINO) and 6-dimethyl-6-dexoxytetracycline (DMG-DMDOT), members of a new generation of tetracyclines, were evaluated by an agar dilution method and were compared with those of tetracycline and minocycline against 224 tetracycline-resistant and 73 tetracycline-susceptible recent clinical isolates of gram-positive cocci, including multiple-antibiotic-resistant methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae. The MICs of DMG-MINO and DMG-DMDOT were up to 500- to 2,000-fold lower than those of tetracycline against methicillin-resistant S. aureus and Streptococcus pneumoniae (MIC for 50% of strains tested [MIC50], < 0.06 microgram/ml). Against Streptococcus groups A, B, C, and G and Enterococcus faecalis, the MIC50 was 0.5 microgram/ml. MIC50s were greater only for coagulase-negative staphylococci (2 micrograms/ml). These data indicate that DMG-MINO and DMG-DMDOT are very potent drugs, and further in vitro and in vivo studies are warranted. 相似文献
67.
JF McCarthy DJ Cook MG Massad Y Sano KJ O''Malley NR Ratliff RW Stewart NG Smedira RC Starling JB Young PM McCarthy 《Canadian Metallurgical Quarterly》1998,14(2):197-200
28 isolates of canine parvovirus type-2 (CPV-2) were obtained from dogs with hemorrhagic gastroenteritis in Italy. The antigenic structure of CPV-2 isolates was characterized, using four discriminating monoclonal antibodies. In addition, four vaccinal strains were examined. Similar to reports from Australia and the United Kingdom, a much higher prevalence of CPV-2a (25/28 isolates) was observed than the other variant type, CPV-2b (3/28 isolates). DNA fragments (2.2 kbp) of representative strains of CPV-2, CPV-2a and CPV-2b were amplified by the polymerase chain reaction (PCR) and the products were digested by the restriction enzymes (RE) RsaI, HpaII, HindIII and PvuII. The RvaI enzyme allows the differentiation of CPV-2 from CPV-2a and CPV-2b. 相似文献
68.
JY Scoazec JF Flejou A D'Errico M Fiorentino A Zamparelli AF Bringuier G Feldmann WF Grigioni 《Canadian Metallurgical Quarterly》1996,24(5):1128-1136
We have analyzed the composition of the tumor stroma and the expression of cell-matrix and cell-cell adhesion molecules in 11 cases of fibrolamellar carcinoma of the liver (FLC), in comparison with 34 cases of hepatocellular carcinoma and 8 cases of focal nodular hyperplasia. Fibrolamellar carcinoma was characterized by the presence of large amounts of tenascin in tumor stroma and by the scarce expression of basement membrane components at the contact of neoplastic clusters. Like normal hepatocytes, neoplastic cells constantly expressed the alpha1 integrin chain, lacked the beta4 integrin chain, and coexpressed E-cadherin and the hepatocyte N-related cadherin. Abnormalities in the expression of cell adhesion molecules, including altered cadherin expression, alphaV integrin chain induction, and CD44 expression, were detected in the majority of cases. The composition of the tumor stroma and the pattern of expression of cell adhesion molecules in fibrolamellar carcinoma were reminiscent of those observed in grade III and grade IV hepatocellular carcinomas. Our results therefore show that, despite its slow local growth and good prognosis, fibrolamellar carcinoma expresses many characteristics usually associated with clinically aggressive malignancies. Further studies are needed to identify the factors responsible for the apparent dissociation between clinical behavior and biological characteristics in this tumor. 相似文献
69.
70.