全文获取类型
收费全文 | 246篇 |
免费 | 11篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 90篇 |
金属工艺 | 2篇 |
机械仪表 | 8篇 |
建筑科学 | 11篇 |
能源动力 | 3篇 |
轻工业 | 27篇 |
水利工程 | 1篇 |
无线电 | 21篇 |
一般工业技术 | 27篇 |
冶金工业 | 18篇 |
原子能技术 | 3篇 |
自动化技术 | 41篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 19篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 4篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1959年 | 1篇 |
1941年 | 2篇 |
1934年 | 2篇 |
排序方式: 共有257条查询结果,搜索用时 15 毫秒
11.
The diffusion coefficient \(D_{{{\text{O}}_{2} }}\), the porosity and the pore structure of mortars produced with a Portland cement and a range of blended cements containing limestone powder, microsilica, portlandite or slag were measured in the non-carbonated and the carbonated state. Additionally, the setup for measuring O2 diffusion was adapted to measure also the CO2 diffusion of the carbonated mortars. The diffusion coefficient \(D_{{{\text{O}}_{2} }}\) and the total porosity were increased in the mortars containing microsilica and slag, while they were decreased in the other mortars due to carbonation. Invariably, the pore structure became coarser in all samples. The relationship between diffusion coefficients \(D_{{{\text{O}}_{2} }}\) and \(D_{{{\text{CO}}_{2} }}\) in the carbonated mortars was always linear, with \(D_{{{\text{O}}_{2} }}\) systematically higher by factor of 1.37. As this factor broadly agrees with what was found in the scant literature about CO2 diffusion, it could be used for estimating \(D_{{{\text{CO}}_{2} }}\) of carbonated mortar and concrete based on measurements of O2 diffusion. 相似文献
12.
Viehweg P Heinig A Lampe D Buchmann J Heywang-Köbrunner SH 《Magma (New York, N.Y.)》1998,7(3):141-152
Purpose The aim of this study was to assess the value of contrast-enhanced (c.-e.) MRI in the follow-up of patients with conservatively
treated breast cancer since detection and exclusion of malignancy may interfere significantly with posttherapeutic changes
within the treated breast.
Material and methods A total of 207 patients with a history of limited surgery and radiation therapy underwent MR imaging, 40 patients were examined
0–12 months and 167 patients were examined later than 12 months after radiotherapy. Suspicious or indeterminate findings were
suggested by clinical examination or conventional imaging in 80 studies. In 127 women, MRI was performed within breast tissue
that was difficult to assess due to scarring or dense breast tissue.
Results Recurrent carcinoma was confirmed in 27 patients by surgical biopsy. All 27 carcinomas, except for one with a slow signal
increase, demonstrated early rise of signal intensity on dynamic T1-weighted contrast enhanced images. During the first year
after therapy, the diagnostic accuracy could not be improved by additional use of c.-e. MRI. Differentiation between posttherapeutic
changes and recurrent carcinoma was frequently not possible because of strong and sometimes early and ill-circumscribed enhancement.
Later than 12 months after therapy enhancement decreased significantly, thus the false positive calls could be reduced from
49 (conventional imaging) to 12 (conventional imaging plus MRI). A total of 12 of 26 recurrences and multifocality in 4/5
cases were diagnosed by MR imaging alone at this time interval.
Conclusion In the first year after therapy, c.-e. MRI is only indicated in selected cases. The results later than 12 months emphasize
that c.-e. MRI may contribute significant additional information. It allows better distinction of posttherapeutic fibrosis
from recurrent carcinoma and proved to be able to detect recurrent disease more sensitive and at an earlier stage. 相似文献
13.
14.
Sonia Domingos-Pereira Karthik Sathiyanadan Lenka Polak Jacques-Antoine Haefliger Martina Schmittnaegel Carola H. Ries Patrice Jichlinski Beat Roth Laurent Derr Denise Nardelli-Haefliger 《International journal of molecular sciences》2023,24(1)
Bacillus Calmette-Guérin (BCG) instillations for the treatment of non-muscle-invasive bladder cancer patients can result in significant side effects and treatment failure. Immune checkpoint blockade and/or decreasing tumor-infiltrating myeloid suppressor cells may be alternative or complementary treatments. Here, we have characterized immune cell infiltration and chemoattractant molecules in mouse orthotopic MB49 bladder tumors. Our data show a 100-fold increase in CD45+ immune cells from day 5 to day 9 tumors including T cells and mainly myeloid cells. Both monocytic myeloid-derived suppressor-cells (M-MDSC) and polymorphonuclear (PMN)-MDSC were strongly increased in day 9 tumors, with PMN-MDSC representing ca. 70% of the myeloid cells in day 12 tumors, while tumor associated macrophages (TAM) were only modestly increased. The kinetic of PD-L1 tumor expression correlated with published data from patients with PD-L1 expressing bladder tumors and with efficacy of anti-PD-1 treatment, further validating the orthotopic MB49 bladder-tumor model as suitable for designing novel therapeutic strategies. Comparison of chemoattractants expression during MB49 bladder tumors grow highlighted CCL8 and CCL12 (CCR2-ligands), CCL9 and CCL6 (CCR-1-ligands), CXCL2 and CXCL5 (CXCR2-ligands), CXCL12 (CXCR4-ligand) and antagonist of C5/C5a as potential targets to decrease myeloid suppressive cells. Data obtained with a single CCR2 inhibitor however showed that the complex chemokine crosstalk would require targeting multiple chemokines for anti-tumor efficacy. 相似文献
15.
16.
Vettiger P. Benedict M.K. Bona G.-L. Buchmann P. Cahoon E.C. Datwyler K. Dietrich H.-P. Moser A. Seitz H.K. Voegeli O. Webb D.J. Wolf P. 《Quantum Electronics, IEEE Journal of》1991,27(6):1319-1331
A concept for full-wafer processing (FWP) and full-wafer testing (FWT) for semiconductor laser fabrication in the AlGaAs-GaAs material system is presented. The approach is based on chemically assisted ion beam etching for the laser-mirror formation. Record values for mirror scattering, optimum mirror reflectivity, and equivalence to cleaved mirrors in terms of laser threshold and efficiency have been achieved. Promising results for uniformity and reproducibility for major laser diode characteristics on processed 2-in wafers have been found. The FWP technology has been extensively used for designing test sites to determine various materials, process, and laser parameters, such as sheet resistance, ridge dimensions, lithographic alignment errors, mirror surface leakage, etc 相似文献
17.
C Küchler SH Heywang-K?brunner U Schauml?ffel P Viehweg H H?fer J Buchmann D Lampe 《Canadian Metallurgical Quarterly》1997,37(8):621-628
PURPOSE: To test the capabilities of vacuum core biopsy (VCB) in the diagnosis of mammographically indeterminate lesions. MATERIALS AND METHODS: 120 patients (131 lesions) were examined using VCB with 14G or 11G vacuum core. RESULTS: VCB was mostly performed because of indeterminate microcalcifications (67 cases) or soft tissue densities/architectural distortion (64 cases). 112 benign changes, 14 DCIS and 5 invasive carcinomas were found. Excellent accuracy was achieved (presently 100%), since complete excision of small lesions/areas (< or = 1 cm) or partial excision of larger lesions was possible. No relevant hematomas or infections occurred. Patients tolerated the painless procedure very well. DISCUSSION: This report confirms our previous experiences. This method promises to replace diagnostic open biopsy of indeterminate or suspicious nonpalpable lesions. 相似文献
18.
Encinar JR Ouerdane L Buchmann W Tortajada J Lobinski R Szpunar J 《Analytical chemistry》2003,75(15):3765-3774
An approach to speciation of selenium incorporated in yeast proteins was developed. The tryptic digest of a water-soluble protein fraction isolated by size-exclusion chromatography was analyzed by reversed-phase HPLC/ICPMS. The selenopeptides selected owing to the detector's elemental specificity were then analyzed by MALDI-TOFMS in order to select target ions for collision-induced dissociation MS. The latter, carried out with an electrospray Q-TOF spectrometer, enabled the sequencing of the selenopeptides detected by HPLC/ICPMS. The approach allowed for the first time the identification of a family of Se-containing proteins resulting from the replacement by selenomethionine of 2-9 methionine residues in a salt-stress-induced protein SIP18 (Mr 8874). The presence of these proteins was confirmed by MALDI-TOFMS of the original (nondigested) protein fraction. Another selenium protein identified was a heat-shock protein HSP12 (Mr 11693) in which the only methionine residue was replaced by selenomethionine. These two Se-containing proteins accounted for more than 95% of selenium in the water-soluble protein fraction. 相似文献
19.
We describe how interactive paper can be used together with a multi-channel web information system to build a platform for
experimenting with multi-modal context-aware mobile information services. As an application, we present a tourist guide for
visitors to an international festival that was developed to investigate alternative modes of information delivery and interaction
in mobile environments. The guide is based around a set of interactive paper documents—an event brochure, map and bookmark.
The brochure and map are augmented with digital services by using a digital pen to activate links and a text-to-speech engine
for information delivery. The digital pen is also used for data capture of event ratings and reviews. The bookmark provides
access to advanced searches and ticket reservations. We describe the architecture and operation of the system, highlighting
the challenges of extending a web information system to support both the generation of the paper documents and the interaction
from these documents, alongside more traditional access channels. Finally, we discuss the range of context-aware interactions
that is supported by our platform. 相似文献
20.
Purpose: This retrospective study was undertaken to investigate the morphologic and dynamic features of in situ and minimally
invasive breast cancer on contrast-enhanced (c.-e.) MR imaging and to examine possible associations to pathology features.
Material and methods: A total of 71 patients underwent MR imaging. T1-weighted FLASH-3D images were obtained before and after
intravenous administration of Gd-DTPA. Histopathologic analysis of 78 lesions revealed ductal carcinoma in situ (DCIS)n=50 and DCIS with microinvasionn=28. MR features were correlated with histopathologic findings. Results: Enhancement in DCIS was focal (73%), diffuse (10%)
or ductal (17%). No enhancement occurred in two cases (4%). In 65% enhancement speed was classified as delayed. There was
a tendency toward a more ill-defined (83 vs. 43%) enhancement pattern in high grade DCIS and a more ductal (29 vs. 12%) and
faster (50 vs. 29%) enhancement in comedo type DCIS. However, significant differences in the enhancement behaviour could neither
be demonstrated between high grade and non high grade DCIS nor between comedo and non comedo type DCIS. No significant differences
were noted between pure and microinvasive DCIS. Conclusion: In this retrospective analysis the majority (96%) of DCIS lesions
show contrast enhancement. However, in only about 50% of DCIS the criteria of a so-called ‘typical’ enhancement behaviour
was fulfilled, that means strong, early, focal ill-circumscribed or ductal. Enhancement that follows a duct is often associated
with malignancy, however this feature was only present in 17% of the cases. c.-e. MR imaging allowed the detection of 25 additional
foci of DCIS. Therefore malignant in situ lesions can be present with atypical enhancement, and should be taken into consideration
in high-risk patients in particular. 相似文献