全文获取类型
收费全文 | 2157篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 97篇 |
金属工艺 | 16篇 |
机械仪表 | 23篇 |
建筑科学 | 19篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
轻工业 | 40篇 |
水利工程 | 1篇 |
无线电 | 71篇 |
一般工业技术 | 182篇 |
冶金工业 | 1646篇 |
原子能技术 | 1篇 |
自动化技术 | 53篇 |
出版年
2019年 | 5篇 |
2018年 | 6篇 |
2016年 | 4篇 |
2014年 | 5篇 |
2013年 | 16篇 |
2012年 | 22篇 |
2011年 | 20篇 |
2010年 | 8篇 |
2009年 | 7篇 |
2008年 | 25篇 |
2007年 | 19篇 |
2006年 | 20篇 |
2005年 | 15篇 |
2004年 | 19篇 |
2003年 | 22篇 |
2002年 | 9篇 |
2001年 | 14篇 |
2000年 | 17篇 |
1999年 | 64篇 |
1998年 | 573篇 |
1997年 | 295篇 |
1996年 | 194篇 |
1995年 | 125篇 |
1994年 | 86篇 |
1993年 | 102篇 |
1992年 | 17篇 |
1991年 | 17篇 |
1990年 | 27篇 |
1989年 | 34篇 |
1988年 | 22篇 |
1987年 | 19篇 |
1986年 | 20篇 |
1985年 | 23篇 |
1984年 | 4篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 19篇 |
1980年 | 27篇 |
1979年 | 14篇 |
1978年 | 13篇 |
1977年 | 57篇 |
1976年 | 66篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 6篇 |
1968年 | 4篇 |
1966年 | 3篇 |
1954年 | 2篇 |
排序方式: 共有2164条查询结果,搜索用时 15 毫秒
11.
12.
JH Winstanley SJ Leinster TG Cooke BR Westley AM Platt-Higgins PS Rudland 《Canadian Metallurgical Quarterly》1993,67(4):767-772
The expression of the protease cathepsin-D has been evaluated using an immunohistochemical technique with a polyclonal antibody in paraffin-embedded tissue from 359 patients treated between the years 1975-1981 for Stage I and II breast cancer. One hundred and twenty seven patients (35%) have strongly positive, granular staining, 138 (38%) are intermediately stained in the cytoplasm, and in 94 (26%) no staining is observed. There is a strong positive association between expression of cathepsin-D and the presence of tumour in axillary lymph nodes (P < 0.006). Expression of the protease is associated with significantly poorer survival of patients in univariate analysis (P = 0.025); however, this is not independent of other tumour variables. 相似文献
13.
The relationship of a member of the transmembrane dystrophin-associated glycoprotein (DAG) complex to acetylcholine receptors (AChRs) was investigated using immunofluorescence techniques at rat neuromuscular junctions (NMJs) viewed en face. These results were compared with those from a similar previous study of dystrophin and an autosomal homologue (utrophin or dystrophin-related protein, DRP) (Bewick et al. Neuro Report 1992; 3: 857-860). The region of highest 43 K DAG (43DAG) labelling projected beyond the AChRs by approximately 0.3 microns, as does that for dystrophin. By contrast DRP labelling precisely co-localizes with the AChRs. These results suggest that at the NMJ, the region of high 43DAG concentration encompasses the area of highest intensity labelling for both DRP and dystrophin. 相似文献
14.
15.
The human mineralocorticoid receptor of the steroid receptor family contains a modular structure with domain E which is considered to be a hormone binding domain. Recombinant protein approaches enabled us to clearly determine that this domain is also able to interact with F-actin (Kd about 2 microM) and G-actin. Moreover, it was revealed that this mineralocorticoid receptor domain/actin interaction was modulated by specific mineralocorticoid ligands. Agonist (aldosterone) steroid binding almost totally (91%) abolished the interaction with F-actin, while antagonist (progesterone) binding allowed more than 30% of this binding. Steroid modulation of the interaction between domain E and actin indicated that this actin binding is specific and could be essential for cellular mineralocorticoid receptor activity. 相似文献
16.
Vladimir Kulyukin Chaitanya Gharpure John Nicholson Grayson Osborne 《Autonomous Robots》2006,21(1):29-41
We present a robot-assisted wayfinding system for the visually impaired in structured indoor environments. The system consists
of a mobile robotic guide and small passive RFID sensors embedded in the environment. The system is intended for use in indoor
environments, such as office buildings, supermarkets and airports. We describe how the system was deployed in two indoor environments
and evaluated by visually impaired participants in a series of pilot experiments. We analyze the system’s successes and failures
and outline our plans for future research and development. 相似文献
17.
18.
FY Ghauri JK Nicholson BC Sweatman J Wood CR Beddell JC Lindon NJ Cairns 《Canadian Metallurgical Quarterly》1993,6(2):163-167
Mutations of ras oncogenes in 37 human stomach cancers and 13 adenomas were investigated with regard to the histological phenotypes using polymerase chain reaction (PCR), allele-specific oligonucleotide hybridization and/or direct sequencing of the PCR products. The ras mutation was found only in one case (2.7%), the histology of which was poorly differentiated adenocarcinoma. We found no mutation in stomach adenomas. The mutation consisted of a guanine-to-adenine transition in the first base of codon 13 of c-Ki-ras which replaced wild-type glycine with serine, indicating that a putative glycine-to-aspartic acid change is not necessarily the critical event for c-Ki-ras gene activation in codon 13. These results further confirm the infrequency of ras mutation in stomach tumors and also suggest that ras mutations are not specific to the differentiated type of stomach cancer. 相似文献
19.
The beta subunit of human chorionic gonadotropin is potentially encoded by six genes, which can be categorized into two types based on a sequence change at codon 117: GCC for the type I and GAC for the type II genes. We previously showed that, whereas type I genes were exclusively expressed in normal breast tissues, expression of type II genes was associated with malignant transformation (Bellet, D., et al. Cancer Res., 57: 516-523, 1997). We designed a simple and robust test (the CG117 assay) that measures the percentage of type II over both types of chorionic gonadotropin beta mRNAs. Normal breast tissues consistently had a negative CG117 index, whereas cancer breast tissues showed indexes ranging from 0 to 100%. The prognostic significance of the CG117 index was investigated in a series of 99 unilateral invasive primary breast cancer patients with known long-term outcome (median follow-up, 9 years). The CG117 index was positive in 48 (48.5%) of the 99 tumor mRNA samples. The index was not significantly associated with standard prognostic parameters, including clinical and macroscopic tumor size, histopathological grade, and lymph node status or steroid receptor status. Patients with a positive CG117 index in primary tumor mRNA had significantly shorter metastasis-free survival (P = 0.014) and overall survival (P = 0.038) after surgery, compared to patients with a negative index. The prognostic significance of the CG117 index persisted in Cox multivariate regression analysis, both for metastasis-free survival (P = 0.008) and overall survival (P = 0.016), together with lymph node status (P = 0.027 and P = 0.009, respectively). These findings indicate that the CG117 index may contribute to the identification of high-risk breast cancer patients. 相似文献
20.
G. Meaden P. G. Partridge M. N. R. Ashfold E. D. Nicholson A. Wisbey 《Journal of Materials Science》1996,31(11):2801-2805
Continuous chemical vapour-deposited diamond-coated fibres with tungsten wire or SiC fibre cores are attractive for reinforcing metals and ceramics. The fibres have been embedded in Ti-6A1-4V alloy to produce a diamond fibre-reinforced composite. Both the fibres and the composite material are extremely difficult to cut without damage by conventional mechanical methods. The use of a Nd-YAG laser to cut these materials is described. 相似文献