全文获取类型
收费全文 | 3359篇 |
免费 | 36篇 |
专业分类
电工技术 | 29篇 |
综合类 | 7篇 |
化学工业 | 119篇 |
金属工艺 | 16篇 |
机械仪表 | 33篇 |
建筑科学 | 73篇 |
矿业工程 | 2篇 |
能源动力 | 15篇 |
轻工业 | 76篇 |
水利工程 | 9篇 |
石油天然气 | 3篇 |
无线电 | 98篇 |
一般工业技术 | 200篇 |
冶金工业 | 2567篇 |
原子能技术 | 9篇 |
自动化技术 | 139篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 8篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 22篇 |
2015年 | 22篇 |
2014年 | 31篇 |
2013年 | 49篇 |
2012年 | 31篇 |
2011年 | 34篇 |
2010年 | 31篇 |
2009年 | 33篇 |
2008年 | 40篇 |
2007年 | 43篇 |
2006年 | 30篇 |
2005年 | 31篇 |
2004年 | 35篇 |
2003年 | 29篇 |
2002年 | 26篇 |
2001年 | 22篇 |
2000年 | 23篇 |
1999年 | 81篇 |
1998年 | 799篇 |
1997年 | 440篇 |
1996年 | 322篇 |
1995年 | 165篇 |
1994年 | 161篇 |
1993年 | 143篇 |
1992年 | 29篇 |
1991年 | 43篇 |
1990年 | 36篇 |
1989年 | 52篇 |
1988年 | 41篇 |
1987年 | 38篇 |
1986年 | 29篇 |
1985年 | 39篇 |
1984年 | 4篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 24篇 |
1980年 | 29篇 |
1978年 | 11篇 |
1977年 | 72篇 |
1976年 | 156篇 |
1975年 | 11篇 |
1973年 | 4篇 |
1908年 | 3篇 |
排序方式: 共有3395条查询结果,搜索用时 15 毫秒
1.
2.
Several variations of cache-based checkpointing for rollback error recovery from transient errors in shared-memory multiprocessors have been recently developed. By modifying the cache replacement policy, these techniques use the inherent redundancy in the memory hierarchy to periodically checkpoint the computation state. Three schemes, different in the manner in which they avoid rollback propagation, are evaluated in this paper. By simulation with address traces from parallel applications running on an Encore Multimax shared-memory multiprocessor, we evaluate the performance effect of integrating the recovery schemes in the cache coherence protocol. Our results indicate that the cache-based schemes can provide checkpointing capability with low performance overhead, but with uncontrollable high variability in the checkpoint interval 相似文献
3.
4.
5.
Garey A. Fox John W. Fuchs Victor F. Medina Kaumudi Atapattu 《Canadian Metallurgical Quarterly》2007,133(3):255-262
Recent research has proposed the use of asphalt and tall-oil-pitch emulsions for stabilizing radioactive contamination deposited on surfaces in urban areas. The objective of this project was to investigate whether surface applied emulsions could capture airborne radioactive particulate. Laboratory experiments included wind-blown particulate capture studies using an acrylic column and particulate retainment experiments using a wind box capable of producing wind speeds of 96?km/h. A probe methodology was developed to relate particulate retainment to a tack force on the emulsion surface. Experiments were also performed to determine the potential for such emulsions to absorb particulate matter into their emulsion matrix. Tall-oil-pitch emulsions outperformed asphalt emulsions in terms of particulate retention, tack force, and the ability to absorb magnesium silicate. Both tall-oil-pitch and asphalt emulsions were capable of extracting 22–24?g?m?2 of powder from particulate-laden airflow. Tall-oil-pitch emulsions were capable of retaining as much as 5–10% of magnesium silicate powder applied (i.e., retainment densities of 10–20?g?m?2) even after seven?days of curing and after applying 96.5?km/h (60?mph) wind. Tall-oil-pitch emulsions were able to absorb surface-applied magnesium silicate (approximately 0.1–0.2?g of magnesium silicate per 1.0?g of emulsion within three?days) into their emulsion matrix, preventing the magnesium silicate from being exposed to the external environment. Initial results with these five different emulsion formulations suggested particulate capture was feasible. Future emulsion formulations (i.e., longer curing times with greater acid concentrations) should be tested to optimize this postdetonation response strategy. 相似文献
6.
7.
FD Fuchs 《Canadian Metallurgical Quarterly》1996,67(4):267-269
We have treated 50 patients with stage III, VI malignant tumors confirmed by pathology. The patients were divided into two groups. One group was treated by combination of chemotherapy and traditional Chinese medicine (treatment group); the other only by chemotherapy (control group). The effect of cancer treatment was evaluated according to the criteria of WHO. The results showed that the effective rate was 80% in treatment group and 52% in control group. The pain relieving rate was 68% in treatment group and 40% in control group (P < 0.01). This fact demonstrates that the application of traditional Chinese medicine can invigorate blood circulation, eliminate blood stasis, soften hardness and dissolve the mass, nourish blood and increase vigor. This kind of application can not only enhance the effect of cancer treatment but also increase the cancer pain relieving rate. 相似文献
8.
E Ashihara AM Vannucchi G Migliaccio AR Migliaccio 《Canadian Metallurgical Quarterly》1997,171(3):343-356
The Word Accentuation Test assesses the accentuation of 30 infrequent Spanish words written without the accentuation mark and is an easy-to-use tool for estimating premorbid intelligence of Spanish-speaking people. Its intraobserver (0.97) and interobserver (0.93) reliabilities and its correlation with the Wechsler Adult Intelligence Scale (.837) and Raven's Progressive Matrices (.655) are high, offering a good prediction of general intelligence. It is resistant to mental deterioration; 20 demented and 40 controls matched by sex, age, and education obtained similar scores. The discrepancies between current and predicted scores in Raven's scale can diagnose mild-moderate dementia with 0.79 accuracy (sensitivity, 0.78; specificity, 0.82). 相似文献
9.
The effect of caseinate and soy protein in the diet on the mutagenicity induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was assessed in-vivo and ex-vivo in the DNA-repair host-mediated assay and liquid suspension assay, respectively. Of the two proteins only casein showed a strong antimutagenic activity over the whole digestive tract, except in the stomach. It is suggested that the molecular structure of a protein determines its protective effect against mutagens: casein lacks secondary and tertiary structure so that amino acids are more readily available for interaction with the mutagen than with the amino acids in soy protein which is a globular protein. 相似文献
10.
AR Santos JC Nery NC Duppre ME Gallo JT Filho PN Suffys WM Degrave 《Canadian Metallurgical Quarterly》1997,46(2):170-172
A case is described in which a pericardial branch of a nongrafted left internal mammary artery communicated directly with the distal left anterior descending artery, following saphenous vein bypass grafting. This type of collateralization following coronary artery bypass surgery seems to be very rare, and perhaps could protect the myocardium from severe ischemia. 相似文献