全文获取类型
收费全文 | 455篇 |
免费 | 29篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 126篇 |
金属工艺 | 9篇 |
机械仪表 | 4篇 |
建筑科学 | 10篇 |
能源动力 | 20篇 |
轻工业 | 64篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
武器工业 | 2篇 |
无线电 | 52篇 |
一般工业技术 | 71篇 |
冶金工业 | 56篇 |
原子能技术 | 3篇 |
自动化技术 | 63篇 |
出版年
2023年 | 10篇 |
2022年 | 25篇 |
2021年 | 22篇 |
2020年 | 18篇 |
2019年 | 18篇 |
2018年 | 18篇 |
2017年 | 23篇 |
2016年 | 24篇 |
2015年 | 17篇 |
2014年 | 11篇 |
2013年 | 32篇 |
2012年 | 19篇 |
2011年 | 21篇 |
2010年 | 31篇 |
2009年 | 24篇 |
2008年 | 15篇 |
2007年 | 11篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 10篇 |
1998年 | 18篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有495条查询结果,搜索用时 0 毫秒
141.
To be able to diagnose systemic candidiasis (SC) and to predict outcomes in SC patients are still challenging tasks for physicians. Previous proteomic studies suggest that anti-Candida methionine synthase (Met6p) IgG antibodies may be a candidate marker for SC. To evaluate their reliability for diagnosis, prognosis and risk stratification in SC, we developed a generic prototype strategy for their measurement in SC. Receiver-operating-characteristic curve analyses revealed a high diagnostic accuracy for this prototype format, which was slightly better to that for the widely used Western blot assays. Multivariate logistic-regression models showed a positive association between serum anti-Met6p IgG antibody levels and SC risk that was independent from established SC risk factors and other baseline variables. After adjusting for and stratifying according to known prognostic factors, a significant trend toward a lower two-month mortality risk with increasing levels was evidenced in SC patients at presentation. We conclude that these antibodies may be useful in discriminating SC from non-SC patients and determining risk stratification in SC. These may also confer protection against SC and be valuable for the design of future immunotherapies. Furthermore, our prototype format has the potential to make impact on other infectious diseases, cancers, allergies or autoimmune disorders. 相似文献
142.
The mechanical relaxation in binary, ternary, quaternary, and quitary bulk metallic glasses with widely different glass-forming ability, or the critical cooling rate, has been studied. A single-roller melt-spinning apparatus was used for preparing thin specimens. The internal friction Q−1 and the oscillation frequency f of the specimens were measured using an inverted torsion pendulum with the free decay method. The measurements were performed from room temperature, through the glass transition temperature Tg, up to the crystallization temperature Tx. As the temperature is increased, the background Q−1 increases, and peaks can usually be seen near Tg and Tx. The shear modulus, which is proportional to f2, is changed near the Q−1 peak. The experimental data are presented and overall features of the results are discussed. 相似文献
143.
Michele Dei Cas Tatiana Carrozzini Giuliana Pollaci Antonella Potenza Sara Nava Isabella Canavero Francesca Tinelli Gemma Gorla Ignazio G. Vetrano Francesco Acerbi Paolo Ferroli Elisa F. Ciceri Silvia Esposito Veronica Saletti Emilio Ciusani Aida Zulueta Rita Paroni Eugenio A. Parati Riccardo Ghidoni Anna Bersano Laura Gatti 《International journal of molecular sciences》2021,22(24)
Moyamoya arteriopathy (MA) is a rare cerebrovascular disorder characterized by ischemic/hemorrhagic strokes. The pathophysiology is unknown. A deregulation of vasculogenic/angiogenic/inflammatory pathways has been hypothesized as a possible pathophysiological mechanism. Since lipids are implicated in modulating neo-vascularization/angiogenesis and inflammation, their deregulation is potentially involved in MA. Our aim is to evaluate angiogenic/vasculogenic/inflammatory proteins and lipid profile in plasma of MA patients and control subjects (healthy donors HD or subjects with atherosclerotic cerebrovascular disease ACVD). Angiogenic and inflammatory protein levels were measured by ELISA and a complete lipidomic analysis was performed on plasma by mass spectrometry. ELISA showed a significant decrease for MMP-9 released in plasma of MA. The untargeted lipidomic analysis showed a cumulative depletion of lipid asset in plasma of MA as compared to HD. Specifically, a decrease in membrane complex glycosphingolipids peripherally circulating in MA plasma with respect to HD was observed, likely suggestive of cerebral cellular recruitment. The quantitative targeted approach demonstrated an increase in free sphingoid bases, likely associated with a deregulated angiogenesis. Our findings indicate that lipid signature could play a central role in MA and that a detailed biomarker profile may contribute to untangle the complex, and still obscure, pathogenesis of MA. 相似文献
144.
Aida Benhamida Mustapha Kaci Sossio Cimmino Clara Silvestre Donatella Duraccio 《大分子材料与工程》2009,294(2):122-129
The chemical modification by melt‐mixing of an EBAGMA terpolymer with LDPE and PET was investigated with the aim to use these EBAGMA/LDPE and EBAGMA/PET blends (in equal weight quantities) as compatibilizer master batches to improve the compatibility of the LDPE/PET system. It is shown that when the EBAGMA terpolymer is melt blended with LDPE, almost 40% of the initial amount of EBAGMA is linked to the LDPE backbone. In contrast, in the case of EBAGMA/PET, FT‐IR spectra indicate the total reactivity between the two components through the reaction of the epoxy group of EBAGMA with the PET terminal groups. SEM analysis shows that both master batches present two well‐interconnected phases.
145.
Instance selection is becoming more and more relevant due to the huge amount of data that is being constantly produced. However,
although current algorithms are useful for fairly large datasets, scaling problems are found when the number of instances
is of hundreds of thousands or millions. In the best case, these algorithms are of efficiency O(n
2), n being the number of instances. When we face huge problems, scalability is an issue, and most algorithms are not applicable.
This paper presents a divide-and-conquer recursive approach to the problem of instance selection for instance based learning
for very large problems. Our method divides the original training set into small subsets where the instance selection algorithm
is applied. Then the selected instances are rejoined in a new training set and the same procedure, partitioning and application
of an instance selection algorithm, is repeated. In this way, our approach is based on the philosophy of divide-and-conquer
applied in a recursive manner. The proposed method is able to match, and even improve, for the case of storage reduction,
the results of well-known standard algorithms with a very significant reduction of execution time. An extensive comparison
in 30 datasets form the UCI Machine Learning Repository shows the usefulness of our method. Additionally, the method is applied
to 5 huge datasets with from 300,000 to more than a million instances, with very good results and fast execution time. 相似文献
146.
Y Aida E Takeuchi T Shinagawa M Tadokoro S Inoue Y Omata M Noro 《Canadian Metallurgical Quarterly》1993,37(4):547-551
A renotropic factor was partially purified by sequential gel filtration and anion exchanger chromatography from plasma of human kidney transplantation donors and a renal cancer patient after uninephrectomy. This activity increased the rate of [3H]thymidine incorporation into DNA in rat cortical tubules, but not in rat liver cells, within the range of 100-200 ng/ml protein. The renotropic activity was detected between 7 and 12 days after uninephrectomy, and at least in 1 case decreased thereafter. This activity was undetected in gel-filtrated plasma of patients after a nonurological surgical procedure. The potency of this renotropic activity and its elution by gel filtration are similar to those displayed by a renal growth factor activity isolated from uninephrectomized rat plasma, as recently reported. 相似文献
147.
M Watanabe K Ono Y Ozeki S Tanaka S Aida Y Okuno 《Canadian Metallurgical Quarterly》1998,28(9):559-562
Recent reports of cancers that produce colony-stimulating factors (CSF) and which are associated with leukocytosis indicate that most are granulocyte CSF-producing tumors. A 71-year-old man with metastatic chest wall tumors from large cell lung cancer with marked leukocytosis and eosinophilia was reported. His maximal leukocyte count was 48300/microliter with 37.5% eosinophils. Granulocyte-macrophage CSF (GM-CSF) activity detected by enzyme-linked immunosorbent assay (ELISA) in serum was 112 pg/ml (normal range < 2.0 pg/ml), but G-CSF was normal. Immunohistochemical detection of GM-CSF protein on a chest wall tumor sample was positive. Irradiation of the chest wall tumor was performed and the leukocyte count decreased temporally. However, he died of respiratory failure due to progressive tumor growth 56 days after admission. Based on these results it appears that autocrine production of GM-CSF is a possible cause of this leukemoid reaction. 相似文献
148.
Maria Consuelo Vanegas Elizabeth Vásquez Aida Juliana Martinez Adriana M. Rueda 《Food Control》2009,20(4):430-432
The aim of our work was to detect Listeria monocytogenes in raw whole milk from five municipalities of Boyacá-Colombia using real-time PCR. A PCR hybridization probe format was used to analyze the presence of L. monocytogenes, using specific primers to amplify a 149 bp fragment from the metalloprotease gene (mpl). In this study on a total number of 81 samples, 21 gave positive results for L. monocytogenes by real-time PCR and 13 samples were positive by conventional method. These results indicate a high presence of this pathogen in this area of the country and that this method is considerably faster than current standard methods. 相似文献
149.
Mao Haiyang Xiong Jijun Zhang Wendong Xue Chenyang Sang Shengbo Bao Aida 《Frontiers of Electrical and Electronic Engineering in China》2007,2(4):449-453
A measurement system was designed and established to test the piezoresistive properties of resonant tunneling diodes (RTDs).
The current-voltage characteristic shifts of RTD at different stress states were detected. The experimental results demonstrate
that the piezoresistive sensitivity of RTD is larger than 1 × 10−8 Pa−1. To accurately represent the piezoresistive properties of RTD, the current-voltage characteristic coherence of the same RTD
was tested. According to the experimental results, the largest relative resistance shift of an RTD in the same measurement
environment is less than 3%, of which 1% is caused by the testing apparatuses.
__________
Translated from Chinese Journal of Semiconductors, 2006, 27(10): 1 789–1 793 [译自: 半导体学报] 相似文献
150.
N Ishiwata T Ikeda K Tokushima S Tozuka S Sakamoto F Marumo S Aida C Sato 《Canadian Metallurgical Quarterly》1998,43(5):971-974
Analysis of H-, K- and N-ras genes for point mutations by PCR-SSCP and direct sequencing of 46 oral SCCs that were previously analyzed for p53 mutations revealed that 9 (20%) had point mutations in either the H-ras or the N-ras. A novel mutation at codon 59 (GCC-ACC) of H-ras thus far reported only in v-H-ras of Harvey murine sarcoma virus was observed in a tumor of the cheek. Majority (8/9) of these mutations were observed in H-ras, one in N-ras and none in K-ras. This study indicated that the ras gene mutation was relatively high in oral cancers associated with tobacco chewing and the ras and p53 mutational events seem to be independent and mutually exclusive. 相似文献