全文获取类型
收费全文 | 1605篇 |
免费 | 53篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 55篇 |
化学工业 | 425篇 |
金属工艺 | 28篇 |
机械仪表 | 29篇 |
建筑科学 | 13篇 |
矿业工程 | 1篇 |
能源动力 | 46篇 |
轻工业 | 86篇 |
石油天然气 | 1篇 |
无线电 | 118篇 |
一般工业技术 | 324篇 |
冶金工业 | 336篇 |
原子能技术 | 75篇 |
自动化技术 | 123篇 |
出版年
2023年 | 14篇 |
2022年 | 24篇 |
2021年 | 53篇 |
2020年 | 38篇 |
2019年 | 30篇 |
2018年 | 39篇 |
2017年 | 33篇 |
2016年 | 55篇 |
2015年 | 22篇 |
2014年 | 41篇 |
2013年 | 81篇 |
2012年 | 63篇 |
2011年 | 95篇 |
2010年 | 50篇 |
2009年 | 57篇 |
2008年 | 52篇 |
2007年 | 53篇 |
2006年 | 49篇 |
2005年 | 45篇 |
2004年 | 38篇 |
2003年 | 35篇 |
2002年 | 29篇 |
2001年 | 25篇 |
2000年 | 31篇 |
1999年 | 35篇 |
1998年 | 119篇 |
1997年 | 82篇 |
1996年 | 60篇 |
1995年 | 25篇 |
1994年 | 50篇 |
1993年 | 30篇 |
1992年 | 16篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 17篇 |
1988年 | 16篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 17篇 |
1972年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有1660条查询结果,搜索用时 15 毫秒
11.
12.
T Takeshita T Arita H Asao N Tanaka M Higuchi H Kuroda K Kaneko H Munakata Y Endo T Fujita K Sugamura 《Canadian Metallurgical Quarterly》1996,225(3):1035-1039
We molecularly cloned a cDNA coding for a novel phosphotyrosine molecule with a 70 kDa molecular mass, named STAM (signal transducing adaptor molecule), which is tyrosine-phosphorylated rapidly after stimulation with various cytokines such as IL-2, IL-3, IL-4, IL-7, GM-CSF, EGF and PDGF. STAM contains an SH3 (Src-homology 3) domain and the ITAM (immunoreceptor tyrosine-based activation motif), suggesting that STAM acts as an adaptor molecule involved in signal transducing pathways from the cytokine receptors. 相似文献
13.
14.
The diploid-like chromosome pairing in polyploid wheat is controlled by the Ph1 (pairing homoeologous) gene that is located on chromosome arm 5BL. By using a combination of cytogenetic and molecular techniques, we report the physical location of the Ph1 gene to a submicroscopic chromosome region (Ph1 gene region) that is flanked by the breakpoints of two deletions (5BL-1 and ph1c) and is marked by a DNA probe (XksuS1). The Ph1 gene region is present distal to the breakpoint of deletion 5BL-1 but proximal to the C-band 5BL2.1. Two other DNA probes (Xpsr128 and Xksu75) flank the region-Xpsr128 being proximal and Xksu75 being distal. The estimated size of the region is less than 3 Mb. The chromosome region around the Ph1 gene is high in recombination as the genetic distance of the region between 5BL-1 breakpoint and C-band 5BL2.1 (not resolved by the microscope) is at least 9.3 cM. 相似文献
15.
This paper deals with the thermal analysis of carbon nanotube (CNT) based composites by meshless element free Galerkin method.
Cylindrical representative volume element (cylindrical RVE) has been chosen to evaluate the thermal properties of nano-composites
using multi-domain and simplified approaches. The values of temperature have been calculated at different points and plotted
against RVE length and RVE radius. A sensitivity analysis of RVE as well as CNT dimensions has been carried out in detail.
The present computations show that the equivalent thermal conductivity is a function of CNT length, CNT radius, RVE length
and RVE radius. Based on present numerical simulations, an approximate formula is proposed to calculate the equivalent thermal
conductivity of nano-composites. The results obtained by simplified approach have been found in good agreement with those
obtained by multi-domain approach. 相似文献
16.
H Hanaue K Kanno M Mukai H Kubo K Tobita H Nakasaki T Tajima T Mitomi R Endo 《Canadian Metallurgical Quarterly》1993,18(1-2):1-4
Increased monoamine metabolism in experimental herpes simplex virus (HSV) encephalitis is well established. Both serotonin (5-HT) and dopamine (DA) systems are affected. HSV invades the raphe nuclei after its entry into the brain stem. However, no studies have been published concerning influences of HSV on the neurotransmitters in the raphe. In the present study, concentrations of 5-HT and DA and their metabolites in the raphe nuclei and related brain regions in rabbits with fulminant HSV encephalitis have been analyzed using high-pressure liquid chromatography. Encephalitis was induced by corneal inoculation with HSV. Homovanillic acid (HVA) and dihydroxyphenyl acetic acid (DOPAC) concentrations and HVA/DA ratios were increased in the raphe nuclei suggesting increased DA turnover. The most substantial changes were bilaterally decreased 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the raphe nuclei. The decrease in the raphe 5-HT was reflected also to the projection areas in the hemispheres, where 5-HT concentrations were lower in HSV-inoculated rabbits than in controls. The changes strongly suggest a direct influence of HSV on serotoninergic neurons. Since the ventral parts of the limbic system have rich serotoninergic afferents from the raphe, this also suggests that HSV may reach hemispheres in HSV encephalitis from the brain stem via the ascending serotoninergic system. 相似文献
17.
D Miyamoto N Endo N Oku Y Arima T Suzuki Y Suzuki 《Canadian Metallurgical Quarterly》1998,21(12):1258-1262
The cytotoxic effects of beta-thujaplicin and five kinds of metal chelates were examined on mouse melanoma B16BL6 cells by cell viability and lactate dehydrogenase (LDH) release assay. Beta-thujaplicin-zinc chelate and beta-thujaplicin-copper chelate had higher cytotoxic effects than beta-thujaplicin, and the 50% effective doses (ED50) of these metal chelates were 12.5 and 25 microM, respectively. In addition, the zinc chelate induced DNA ladder formation in B16BL6 cells, as shown by the DNA fragmentation assay, suggesting that cell death induced by the zinc chelate is apoptosis. The zinc chelate also had a cytotoxic effect and induced DNA fragmentation on other tumor cell lines: HeLa, Meth A, and B16F1 cells, but not on normal human diploid fibroblasts FS-4. These results suggest that beta-thujaplicin-zinc chelate induces apoptotic cell death in various tumor cell lines and is a potent antitumor agent for tumor cells including malignant melanomas. 相似文献
18.
O Nohara T Imai K Saneyoshi T Endo H Nagakura M Ono H Moriyama 《Canadian Metallurgical Quarterly》1996,45(6):562-569
Titers of IgE antibody specific for the pollen of Chamaecyparis obtusa (C. obtusa) were determined by AlaSTAT and CAP-RAST in 221 patients with Japanese cedar pollinosis. IgE antibody to C. obtusa tested positive by CAP-RAST at a higher rate (80.5%) than by AlaSTAT (52.6%). The results obtained from the two assays were compared with those from intradermal skin test. CAP-RAST had a higher sensitivity than that of AlaSTAT. Because the two methods showed no differences in the determination of IgE antibody specific for Cryptomeria japonica, the above differences between AlaSTAT and CAP-RAST are surmised to be ascribable to the differences of C. obtusa antigen used in the both assays. 相似文献
19.
T Kuroki K Yagita H Sugiyama S Yamai T Fukuma Y Katsube T Endo 《Canadian Metallurgical Quarterly》1998,72(10):1064-1069
PURPOSE: To determine possible cognitive and behavioral effects of antiepileptic drug (AED) therapy by assessing children with newly diagnosed epilepsy before and after initiation of treatment. A comparison group of children with diabetes mellitus (DM) was included to control for the effects of practice, maturation, and chronic illness. METHODS: Baseline neuropsychological assessments were completed for children with epilepsy (n = 37) and children with DM (n = 26) recruited through outpatient clinics at a regional children's hospital. Children were reevaluated 6 months from baseline testing. At follow-up, children with epilepsy had therapeutic AED levels and controlled seizures. Statistical analysis included a between-group repeated measures ANCOVA with pretest scores serving as the covariate. RESULTS: Significant differences between groups were not found for any cognitive or behavioral factors, including attention (p < 0.24), immediate memory (p < 0.24), delayed memory (p < 0.10), complex motor speed (p < 0.19), or behavior problems (p < 0.89). CONCLUSIONS: Changes in performance on cognitive and behavioral measures were not different for children treated with AEDs and controls. Although adverse effects may be associated with prolonged treatment, results would not suggest adverse effects from AED monotherapy during the first 6 months of therapy. 相似文献
20.
Microsystem Technologies - TEMPO-oxidized cellulose nanofiber (TOCN) has been drawing much attention as a useful material for preparation of transparent and stiff films or substrates. In this work,... 相似文献