全文获取类型
收费全文 | 1160篇 |
免费 | 32篇 |
专业分类
电工技术 | 1篇 |
综合类 | 3篇 |
化学工业 | 83篇 |
金属工艺 | 5篇 |
机械仪表 | 9篇 |
建筑科学 | 7篇 |
能源动力 | 8篇 |
轻工业 | 19篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 32篇 |
一般工业技术 | 69篇 |
冶金工业 | 908篇 |
自动化技术 | 43篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 17篇 |
2014年 | 14篇 |
2013年 | 40篇 |
2012年 | 14篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 13篇 |
2007年 | 13篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 18篇 |
1998年 | 256篇 |
1997年 | 159篇 |
1996年 | 107篇 |
1995年 | 72篇 |
1994年 | 57篇 |
1993年 | 54篇 |
1992年 | 10篇 |
1991年 | 14篇 |
1990年 | 19篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1978年 | 1篇 |
1977年 | 36篇 |
1976年 | 76篇 |
1975年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1192条查询结果,搜索用时 15 毫秒
101.
AH Rezvani DH Overstreet Y Yang IM Maisonneuve UK Bandarage ME Kuehne SD Glick 《Canadian Metallurgical Quarterly》1997,58(2):615-619
We previously reported that single administration of ibogaine, an indol alkaloid with antiaddictive properties, dose dependently reduced alcohol intake in three strains of alcohol-preferring rats. The present study examined the effect of different doses of a newly developed nontoxic ibogaine analogue, 18-methoxycoronaridine (18-MC), on alcohol intake. Selectively bred alcohol-preferring rats received a single intraperitoneal injection of vehicle or 5, 20 and 40 mg/kg of 18-MC at 9:30 AM, and their consumption of alcohol, water and food was measured for 24 h. Our results demonstrate that a single injection of 18-MC significantly and dose dependently attenuated alcohol consumption and preference and commensurately increased water intake. Only the highest dose of 18-MC significantly decreased food intake. Although the true mechanism of action of 18-MC in suppressing alcohol intake is not yet fully understood, it may, like ibogaine, exert its attenuating effects on alcohol consumption by modulating neurotransmitters believed to be involved in the regulation of alcohol intake. 相似文献
102.
Chi Hsing Tsai Milind D. Deo Francis V. Hanson Alex G. Oblad 《Petroleum Science and Technology》1992,10(9):1437-1459
The proton and carbon-13 nuclear magnetic resonance characteristics of the native Whiterocks bitumen were determined by comparing the spectra of the samples to literature assignments. The tentative structural assignments of pyrolysis products were also obtained from the spectra of Curie-point low voltage mass spectrometric analysis. The results obtained from proton and carbon-13 nuclear magnetic resonance and pyrolysis-mass spectrometry analysis suggested that the native bitumen consists mostly of short- and long-chain (i.e., normal and isoprenoid chains) alkylsubstituents attached to polycyclic naphthenic, naphtheno-aromatic and/or aromatic moieties. 相似文献
103.
IM Spivak NM Pleskach VM Mikhel'son D Bootsma A Kolman 《Canadian Metallurgical Quarterly》1997,39(6):420-434
The action of ionizing radiation and chemical mutagens--epoxides (ethylene oxide, propylene oxide, epichlorohydrin)--upon survival and repair processes in xeroderma pigmentosum (XP2SP) and Cockayne syndrome (CS1SP) patients' cells was studied, compared to healthy donor's cells VH-10 and C5RO. Ionizing radiation was demonstrated to enhance significantly higher survival decrease of XP2SP and CS1SP fibroblasts, compared to healthy donor's cells, according to the cloning efficiency criterion. In contrast to this, no significant difference between XP2SP and healthy donor's cells was found, according to cells' ability to replicative DNA synthesis after gamma irradiation. Differences in survival of mutant cells and healthy donor's cells after treatment by epoxides were found significant only following XP2SP being treated by ethylene oxide. DNA single-string breaks in XP2SP and in CS1SP cells treated by mutagens studied were proved to occur with the same frequency as in the DNA of the control cells; however the DNA repair according to this criterion was significantly suppressed in mutant cells. 相似文献
104.
J Koerts MM Velraeds AE Soffers J Vervoort IM Rietjens 《Canadian Metallurgical Quarterly》1997,10(3):279-288
In the present study, the effects of extracellular magnesium concentration ([Mg2+]ex) on stimulus-secretion coupling processes were investigated in rat gastric parietal cells in vitro. Extracellular magnesium reduction resulted in (1) an increase of basal intracellular free calcium concentration ([Ca2+]in), (2) an enhancement of both carbachol and thapsigargin-induced calcium responses, (3) an improved filling state of intracellular calcium stores, (4) an increase of both basal and carbachol-induced acid secretion, whereas intracellular adenosine 3',5'-cyclic monophosphate (cyclicAMP) levels and histamine stimulated acid secretion were not affected. The effects of high [Mg2+]ex were opposite to the described results, except that high [Mg2+]ex was able to decrease significantly histamine-stimulated cyclicAMP levels and acid secretion. These findings indicate a modulatory role of [Mg2+]ex on the intracellular signalling processes and acid secretory properties in rat parietal cells. These effects seemed to be mediated by regulating (1) calcium loading capacity of intracellular stores, (2) the permeability of the calcium influx pathway, and (3) the formation of cyclicAMP. 相似文献
105.
Sixteen phages active against bacteria of the genus Serratia have been divided into 4 groups on the basis of the study of their biological properties. As a result, 5 typing phages have been selected, which permitted the typing of 77.3% of S. marcescens cultures under study, divided into 13 phage types. 相似文献
106.
IM Rabinovich IV Bezrukova VV Khazanova EA Zemskaia NA Dmitrieva 《Canadian Metallurgical Quarterly》1997,76(4):12-17
Fifty-two patients with lichen planus were examined over the course of disease using clinical, microbiological, and histological methods. Treatment protocols aimed at normalization of microbiocenosis have been developed, based on the detected microbiological and histological changes. 相似文献
107.
T Sorahan P Prior RJ Lancashire SP Faux MA Hultén IM Peck AM Stewart 《Canadian Metallurgical Quarterly》1997,76(11):1525-1531
Parental smoking data have been reabstracted from the interview records of the Oxford Survey of Childhood Cancers (deaths from 1971 to 1976). Reported smoking habits for the parents of 2587 children who died with cancer were compared with similar information for the parents of 2587 healthy controls (matched pairs analysis). Maternal daily consumption of cigarettes and paternal use of pipes or cigars were unimportant, but there was a statistically significant positive trend between paternal daily consumption of cigarettes and the risk of childhood cancer (P < 0.001). This association could not be explained by maternal smoking, social class, parental ages at the birth of the survey child, sibship position or obstetric radiography. Relations between maternal consumption of cigarettes and birth weights suggested that (maternal) smoking data were equally reliable for case and control subjects. About 14% of all childhood cancers in this series could be attributable to paternal smoking. These data were combined with smoking data from two previously published reports from the Oxford Survey (deaths from 1953 to 1955, deaths from 1977 to 1981) to obtain further information on risks for different types of cancer and different ages at onset of disease. Paternal cigarette smoking emerged as a potential risk factor both for the generality of childhood cancer and for all ages at onset. 相似文献
108.
TV Nasedkina AE Kuz'minova SA Surkov NM Pleskach VV Prokof'eva IM Spivak VM Mikhel'son AI Poletaev 《Canadian Metallurgical Quarterly》1997,39(9):809-821
Lymphoblastoid cell lines from patients with xeroderma pigmentosum (2 forms) and progeria (unusual form) were established using transformation of peripheral blood lymphocytes by Epstein--Barr virus. The influence of different UV doses on cell vitality, proliferation and cell cycle progression was studied by means of flow cytometry. The cell vitality was determined after incubation of cells with etidium bromide and FDA. We used cytograms with two logarithmic signals (log green/log red) to discriminate the cell cycle status. Cell cultures were used with density of 500,000 cells per 1 ml, previously synchronized at G-phase by the incubation in a medium with low serum content. The effect of UV irradiation was followed during 72 h. Among four analysed cell lines only line XP2SP demonstrated enhanced UV sensitivity, expressed by decreasing of the amount of living cells after the UV dose of 2.5 J/m2 and higher. The cell cycle studies showed that cells were blocked in S-phase and simultaneously the amount of apoptotic cells with both reduced DNA content and ability to bind FDA was seen increased. Similar events were observed in the control line only after the dose of 20 J/m2 and higher. 相似文献
109.
The possible relationship between physeal diseases and physeal form prompted investigation of change in steepness of the physis in young foals. The distal and proximal aspects of the longbones were sawn sagittally in the right and frontally in the left bones. The slabs were washed to remove saw debris, arranged in order and inspected. The proximal physes had a flat or gently arched form, without obvious inclination. In the distal physes there were distinct inclinations. Inspection of an identical slab from the medial aspect of the distal radius of two series of foals of different breeds showed that the degree of inclination of the physis with respect to the long axis of the bone increased with age. In a further series of foals, the angle of inclination was measured from radiographs of identical sagittal and frontal slabs of the distal radius. A line drawn through the secondary spongiosa was produced to intersect a line drawn along the physis where it was mostly steeply inclined, and the angle measured. The angle decreased (physeal inclination increased) with increasing age, up to 35-90 days. The steepness in the lateral aspect of the physis was similar to that in the medial aspect, although evident in a different plane. 相似文献
110.