全文获取类型
收费全文 | 3265篇 |
免费 | 104篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 42篇 |
综合类 | 7篇 |
化学工业 | 551篇 |
金属工艺 | 85篇 |
机械仪表 | 48篇 |
建筑科学 | 156篇 |
矿业工程 | 13篇 |
能源动力 | 117篇 |
轻工业 | 312篇 |
水利工程 | 35篇 |
石油天然气 | 5篇 |
无线电 | 217篇 |
一般工业技术 | 452篇 |
冶金工业 | 815篇 |
原子能技术 | 24篇 |
自动化技术 | 499篇 |
出版年
2022年 | 21篇 |
2021年 | 36篇 |
2020年 | 35篇 |
2019年 | 36篇 |
2018年 | 62篇 |
2017年 | 49篇 |
2016年 | 64篇 |
2015年 | 40篇 |
2014年 | 71篇 |
2013年 | 167篇 |
2012年 | 114篇 |
2011年 | 152篇 |
2010年 | 119篇 |
2009年 | 112篇 |
2008年 | 166篇 |
2007年 | 154篇 |
2006年 | 129篇 |
2005年 | 105篇 |
2004年 | 104篇 |
2003年 | 89篇 |
2002年 | 81篇 |
2001年 | 59篇 |
2000年 | 47篇 |
1999年 | 59篇 |
1998年 | 111篇 |
1997年 | 93篇 |
1996年 | 83篇 |
1995年 | 59篇 |
1994年 | 69篇 |
1993年 | 70篇 |
1992年 | 52篇 |
1991年 | 30篇 |
1990年 | 42篇 |
1989年 | 33篇 |
1988年 | 26篇 |
1987年 | 41篇 |
1986年 | 42篇 |
1985年 | 57篇 |
1984年 | 48篇 |
1983年 | 46篇 |
1982年 | 38篇 |
1981年 | 42篇 |
1980年 | 40篇 |
1979年 | 23篇 |
1978年 | 26篇 |
1977年 | 33篇 |
1976年 | 34篇 |
1975年 | 20篇 |
1974年 | 30篇 |
1972年 | 15篇 |
排序方式: 共有3378条查询结果,搜索用时 15 毫秒
11.
12.
Chapman Derek S.; Uggerslev Krista L.; Webster Jane 《Canadian Metallurgical Quarterly》2003,88(5):944
This field study examined applicant reactions (N = 802) toward face-to-face as compared with technology-mediated interviews (through videoconferencing or by telephone) for 346 organizations. Face-to-face interviews were perceived as more fair and led to higher job acceptance intentions than were videoconferencing and telephone interviews. Perceived interview outcomes were higher with face-to-face and telephone interviews over videoconferencing. Self-monitoring moderated the relationship between interview medium and perceptions of fairness. Specifically, this relationship was (a) positive for face-to-face, (b) negative for telephone, and (c) nonsignificant for videoconferencing interviews. Moreover, the number of offers an applicant received moderated the relationship between interview medium over, and perceived fairness. The relationship between number of offers and perceived fairness was positive for face-to-face and negative for technology-mediated interviews. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
13.
Atkinson-Leadbeater Karen; Nuttley William M.; van der Kooy Derek 《Canadian Metallurgical Quarterly》2004,118(6):1206
A learning event can be dissociated into 3 components: acquisition, storage, and recall. When the laboratory wild-type strain of Caenorhabditis elegans (N2 strain) is exposed to benzaldehyde in the absence of food, the worms display a reduction of their attractive response to this volatile odorant. This results from the association between benzaldehyde and a nutrient-deficient environment. Another wild-type isolate, the CB4856 strain, fails to display this decreased response to benzaldehyde after exposure to benzaldehyde in the absence of food. However, like the N2 strain, when tested to isoamyl alcohol after benzaldehyde conditioning, the CB4856 strain displays a decreased isoamyl alcohol response. Therefore, the CB4856 strain does not have an acquisition deficit, but it suffers from a recall deficit specific to benzaldehyde. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
14.
This paper studies a system of partial differential equations modelling the behaviour of a reverse flow reactor. For the parameters appropriate for the oxidation of ammonia on a Pt/Al2O3 catalyst in a typical laboratory set-up, the reactor may be split into regions where approximate formulas that determine its behaviour are deduced. Numerical calculations are presented and can be used to compare with the analytical formulas. The physical insight gained from the asymptotic analysis suggests a new switching strategy which is the subject of numerical experiments. The switching strategy is found to be efficient at minimising the ammonia exiting the reactor after reversal. 相似文献
15.
16.
17.
H Chen M Kalaitsidaki AC Warren D Avramopoulos SE Antonarakis 《Canadian Metallurgical Quarterly》1993,15(3):621-625
PURPOSE: To evaluate the therapeutic effectiveness of a combined chemoradiotherapy program, followed by surgery in selected cases, in Stage III non-small cell lung cancer. METHODS AND MATERIALS: Between August 1988 and February 1990, 43 patients Staged IIIa-b (UICC 1987, 58% IIIb) have been treated with concomitant chemotherapy (cisplatin 15 mg/m2 and VP16 75 mg/m2, 5 days a week on week 1 and 5) and radiotherapy (40 Gy split course, 2 Gy/day on week 1, 2, 5, and 6), followed by attempted curative thoracotomy or more cycles of full dose chemotherapy with the same two drugs. RESULTS: Planned chemoradiotherapy has been given to 91% of patients; 13/43 patients have been operated, with 12 complete resections and three (7%) pathological complete responses. Toxicity was significant, with two postoperative deaths and two fatal radiation pneumonitis. Crude progression-free survival rate is 21% at 30 months, with nine patients (21%) alive and free from progression at follow-up times ranging from 31 to 49 months. Subset survival analysis showed a possibly greater therapeutic effect for non-squamous histology as compared to squamous carcinoma. CONCLUSION: These results are encouraging in a cohort of patients with quite advanced disease (58% Stage IIIb). 相似文献
18.
RW Sidwell DF Smee RP Warren JH Huffman BJ Gilbert RA Burger FC Pearson 《Canadian Metallurgical Quarterly》1993,20(4):279-292
ImuVert, a sterile preparation composed primarily of Serratia marcescens membrane vesicles and ribosomes, was significantly inhibitory to murine cytomegalovirus (MCMV) infections in BALB/c mice. Antiviral activity was manifested as increased survivor number and decreased recoverable virus titers in spleens, lungs and salivary glands. Treatments were intraperitoneal (i.p.) beginning 24 h pre, 4 h post- or 24 h post-virus inoculation and then repeated 4 days later. Doses of 5, 16 or 50 micrograms/mouse were effective; 160 micrograms/mouse, which caused host weight loss in toxicity controls, was not inhibitory to the infection. A single i.p. treatment of mice substantially augmented natural killer (NK) cell activity and increased total B-cells, while reducing total T- and T-helper cells. A late (48 h) decline in T-cell function and transient increases in B-cell function were observed in the treated animals. Serum interferon was not induced. Mice pretreated with anti-asialo GM1 antibody to reduce their NK cell populations, then infected with MCMV and treated with ImuVert were protected to the same degree as normal animals. Severe combined immunodeficient mice infected with MCMV and treated with ImuVert were not protected from the infection. These data suggest ImuVert to act by a mechanism other than NK cell activation in preventing MCMV infections. 相似文献
19.
Brefeldin A (BFA) has been reported to cause disassembly of the Golgi. We have used three-dimensional (3-D) high-resolution scanning electron microscopy (HRSEM) to investigate these effects in human skin fibroblast cells. The spontaneous reassembly during prolonged exposure to BFA and some effects of forskolin were observed. A BFA concentration of 5μg/ml caused Golgi complexes to become vesicular, resulting in a progressive decrease in the size of the Golgi. Morphologic changes were visible within 2 min of BFA incubation, and by 30 min no identifiable Golgi could be found. Spontaneous reassembly of the Golgi apparatus upon the removal of the BFA or with continued long-term exposure with BFA could not be confirmed. Preliminary experiments with forskolin were not effective in reversing or inhibiting the effects of BFA in human fibroblast cells grown in culture. This inability for spontaneous reassembly and nonreversal by forskolin may reflect a differential effect of BFA in various cell types. HRSEM has proven to be useful for observing 3-D morphologic effects of BFA in Golgi. 相似文献
20.
Warren J. Batchelor Trevor R. Finlayson Anita K. Gross 《Journal of the American Ceramic Society》1993,76(7):1895-1897
The measured plastic deformation of Mg-PSZ under stress contains contributions from both transformation and microcracking. A method is described to separate the contributions from transformation and microcracking for samples deformed in uniaxial tension. Such a separation enables the ratio of the longitudinal to transverse strains arising from the transformation to be estimated. The results are compared to the predictions of the shear–dilatation model of Chen and Reyes-Morel. Serious discrepancies are found between the experimental results and the predictions of the model and the possible reason for this is discussed. 相似文献