全文获取类型
收费全文 | 7126篇 |
免费 | 17篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 105篇 |
金属工艺 | 33篇 |
机械仪表 | 7篇 |
建筑科学 | 32篇 |
能源动力 | 17篇 |
轻工业 | 46篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
武器工业 | 1篇 |
无线电 | 57篇 |
一般工业技术 | 88篇 |
冶金工业 | 6669篇 |
原子能技术 | 2篇 |
自动化技术 | 71篇 |
出版年
2022年 | 6篇 |
2021年 | 10篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 21篇 |
2012年 | 23篇 |
2011年 | 32篇 |
2010年 | 22篇 |
2009年 | 17篇 |
2008年 | 22篇 |
2007年 | 24篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 10篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 17篇 |
1999年 | 179篇 |
1998年 | 1980篇 |
1997年 | 1160篇 |
1996年 | 786篇 |
1995年 | 402篇 |
1994年 | 364篇 |
1993年 | 400篇 |
1992年 | 62篇 |
1991年 | 110篇 |
1990年 | 108篇 |
1989年 | 100篇 |
1988年 | 111篇 |
1987年 | 94篇 |
1986年 | 84篇 |
1985年 | 63篇 |
1984年 | 8篇 |
1983年 | 18篇 |
1982年 | 37篇 |
1981年 | 56篇 |
1980年 | 63篇 |
1979年 | 4篇 |
1978年 | 34篇 |
1977年 | 192篇 |
1976年 | 364篇 |
1975年 | 13篇 |
1964年 | 3篇 |
1955年 | 4篇 |
1954年 | 3篇 |
排序方式: 共有7143条查询结果,搜索用时 31 毫秒
101.
Congenital pulmonary lymphangiectasis with chylothorax: a heterogeneous lymphatic vessel abnormality
P Moerman K Vandenberghe H Devlieger C Van Hole JP Fryns JM Lauweryns 《Canadian Metallurgical Quarterly》1993,47(1):54-58
We describe the generation of a new antipeptide antibody that binds to the centromeric region of human mitotic chromosomes. This antibody was raised against a synthetic peptide corresponding to the 481-493 amino acid sequence of the human CENP-B autoantigen. Immunofluorescence analysis revealed that this anti-CENP-B serum showed an identical pattern to the human CREST anticentromere autoantibody in both mitotic cells and interphase nuclei. Immunoblotting showed that this antibody reacts with the recombinant human CENP-B autoantigen, indicating that it is directed to the 80-kDa centromere polypeptide. We have used this serum to determine, by indirect immunofluorescence, whether CENP-B is conserved in different mammalian species. Surprisingly, the human antipeptide antibody does not react with the centromeric proteins of cultured mouse, hamster, or Indian muntjac cells. Because the CENP-B gene has been cloned in human and mouse, our results suggest that the CENP-B epitope used as an immunogen in this study is not ubiquitous in mammalian cells, and that we have most probably established a monospecific antibody to the human centromere. 相似文献
102.
Abnormal hepatic mitochondrial respiration and cytochrome C oxidase activity in rats with long-term copper overload 总被引:2,自引:0,他引:2
RJ Sokol MW Devereaux K O'Brien RA Khandwala JP Loehr 《Canadian Metallurgical Quarterly》1993,105(1):178-187
BACKGROUND: Dietary copper overload in the rat is associated with morphological abnormalities and lipid peroxidation of hepatic mitochondria. This study was designed to determine if copper hepatotoxicity was associated with functional alterations in mitochondrial respiration in conjunction with lipid peroxidation. METHODS: Weanling male rats were pair-fed for 8 weeks on diets containing normal or high levels of copper in combination with sufficient vitamin E. Serum and liver samples were obtained, and hepatic mitochondria were isolated by differential centrifugation. RESULTS: Oxidant injury (decreased levels of hepatic glutathione and alpha tocopherol and increased levels of mitochondrial thiobarbituric acid-reacting substances) was present in the copper-overloaded rats. Serum aminotransferase levels correlated with concentrations of mitochondrial copper and thiobarbituric acid-reacting substances. Copper overload caused a decrease in state 3 respiration and the respiratory control ratio in hepatic mitochondria when several electron donors were used. Analysis of the oxidoreductase activities of the four mitochondrial electron transport protein complexes showed that complex IV (cytochrome C oxidase) activity was reduced by 60% in copper overload. CONCLUSIONS: Functional abnormalities of mitochondria accompany lipid peroxidation and the morphological alterations caused by copper overload, supporting the hypothesis that the mitochondrion is one of the major intracellular targets in copper hepatotoxicity. 相似文献
103.
104.
105.
Because most therapeutic agents used for viral infections are relatively new, experience with their adverse effects is still evolving. Hepatic toxicity has not been among the most important concerns with this class of drugs so far. Liver damage has been increasingly noted with accumulating experience, especially with antiretroviral drugs and those used to treat chronic hepatitis (e.g., fialuridine), but it is often difficult to distinguish between effects of therapy and of the underlying disease. It is important for clinicians to be aware of the possibility of hepatotoxicity in such situations, and further reporting of adverse experiences should contribute to more definitive evaluation of the potential influence of antivirals on liver function. 相似文献
106.
107.
108.
Sera from 82 cases of leptospirosis (confirmed by micro-agglutination tests or IFAT) and 108 patients with other diseases were investigated using the microcapsule agglutination test (MCAT) for leptospirosis. The overall sensitivity (90.2%), specificity (96.3%), positive predictive value (94.9%), negative predictive value (92.9%), and accuracy of the MCAT (93.7%) were encouraging. MCAT is simple, can be performed by unskilled personnel with minimum laboratory facilities, and produces results in 3 h. MCAT would be a reliable serodiagnostic test for rapidly screening individuals for leptospirosis, in various geographical areas of Thailand. 相似文献
109.
DJ MacGowan MN Janal WC Clark RN Wharton RM Lazar RL Sacco JP Mohr 《Canadian Metallurgical Quarterly》1997,49(1):120-125
BACKGROUND: Questionnaire-based surveys from several countries have consistently detected adverse health associated with home dampness and mould growth. METHODS: To test the validity of questions commonly used to indicate the presence of indoor mould, questionnaires were administered in 403 homes where dust samples were taken for viable fungi and air samples for ergosterol. RESULTS: Geometric mean concentrations of the total viable fungi were 255 (SE 116) x 10(3) CFU/g when mouldy odours were reported and 155 (SE 55) when odours were not reported (P = 0.01). Similarly, reported water damage was associated with a 50% increase (P = 0.06). Geometric mean concentrations of the predominantly indoor-source fungi, Aspergillus plus Penicillium, were twice as high when mould or mildew was reported than when not mentioned (P = 0.01). The presence of reported mould or water damage was unrelated to the presence of detectable levels of ergosterol. There was evidence for reporting bias: in the presence of low concentrations of viable fungi in dust, respondents reporting allergies were more likely to report visible mould growth (odds ratio [OR] = 1.8, 95% confidence interval [CI]: 0.9-3.5, P = 0.10. In the presence of elevated concentrations of dust fungi, respondents who smoked were less likely to report visible mould growth, (OR = 0.4, 95% CI: 0.2-0.7, P = 0.005). CONCLUSIONS: Reported mould, water damage, and mouldy odours were associated with elevated levels of indoor fungi. However, inaccuracy was high and there was evidence of a systematic reporting bias. Future research should concentrate on developing accurate objective measures of exposure to fungi, and then use this information to develop valid questionnaires. Currently, objective measures not questionnaires, are recommended to clarify the health effects of indoor fungi. 相似文献
110.