全文获取类型
收费全文 | 1075篇 |
免费 | 59篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 208篇 |
金属工艺 | 6篇 |
机械仪表 | 12篇 |
建筑科学 | 32篇 |
矿业工程 | 4篇 |
能源动力 | 42篇 |
轻工业 | 189篇 |
水利工程 | 6篇 |
无线电 | 74篇 |
一般工业技术 | 161篇 |
冶金工业 | 250篇 |
原子能技术 | 2篇 |
自动化技术 | 141篇 |
出版年
2023年 | 3篇 |
2022年 | 23篇 |
2021年 | 34篇 |
2020年 | 18篇 |
2019年 | 25篇 |
2018年 | 21篇 |
2017年 | 35篇 |
2016年 | 21篇 |
2015年 | 17篇 |
2014年 | 35篇 |
2013年 | 54篇 |
2012年 | 45篇 |
2011年 | 58篇 |
2010年 | 56篇 |
2009年 | 53篇 |
2008年 | 46篇 |
2007年 | 46篇 |
2006年 | 41篇 |
2005年 | 25篇 |
2004年 | 35篇 |
2003年 | 30篇 |
2002年 | 21篇 |
2001年 | 19篇 |
2000年 | 14篇 |
1999年 | 30篇 |
1998年 | 93篇 |
1997年 | 56篇 |
1996年 | 31篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 7篇 |
1991年 | 11篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1976年 | 8篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有1135条查询结果,搜索用时 9 毫秒
981.
A Olmos JJ Camarena JM Nogueira JC Navarro J Risen R Sánchez 《Canadian Metallurgical Quarterly》1998,36(4):1128-1134
The optimization of an arbitrarily primed PCR method for typing 96 methicillin-resistant Staphylococcus aureus (MRSA) isolates was compared with pulsed-field gel electrophoresis. Identical results in the differentiation of MRSA clones and identification of the main cluster that included 82 strains (88% of patients) were obtained by both techniques. 相似文献
982.
The present paper describes the presence of a special cell located in the ependymal wall at the level of the paraventricular nucleus. At this level, ultrastructural observation of these ependymal cells, unlike most other mammalian species, shows the presence of nucleolus-like bodies in their cytoplasm and occasionally basal processes. These processes appear perpendicular to the ependymal surface and end in contact with the basal membrane of hypothalamic capillaries. Mitochondria, endoplasmic reticulum and numerous filaments are present in the basal processes. Nucleolus-like bodies or nematosomes consist of round or ovoid unbound masses of granular appearing material of variable density located in the apical cytoplasm of the cells. Some of their ultrastructural characteristics are similar to other ependymal specialized cells which are classically termed tanycytes. These findings point out the possibility that those special cells may also be implicated in a ventricle-blood vessel communication. 相似文献
983.
P Navarro L Caveda F Breviario I Mandoteanu MG Lampugnani E Dejana 《Canadian Metallurgical Quarterly》1995,270(52):30965-30972
Vascular endothelial cadherin (VE-cadherin, cadherin-5, or 7B4) is an endothelial specific cadherin that regulates cell to cell junction organization in this cell type. Cadherin linkage to intracellular catenins was found to be required for their adhesive properties and for localization at cell to cell junctions. We constructed a mutant form of VE-cadherin lacking the last 82 amino acids of the cytoplasmic domain. Surprisingly, despite any detectable association of this truncated VE-cadherin to catenin-cytoskeletal complex, the molecule was able to cluster at cell-cell contacts in a manner similar to wild type VE-cadherin. Truncated VE-cadherin was also able to promote calcium-dependent cell to cell aggregation and to partially inhibit cell detachment and migration from a confluent monolayer. In contrast, intercellular junction permeability to high molecular weight molecules was severely impaired by truncation of VE-cadherin cytoplasmic domain. These results suggest that the VE-cadherin extracellular domain is enough for early steps of cell adhesion and recognition. However, interaction of VE-cadherin with the cytoskeleton is necessary to provide strength and cohesion to the junction. The data also suggest that cadherin functional regulation might not be identical among the members of the family. 相似文献
984.
A Anadón Navarro 《Canadian Metallurgical Quarterly》1976,2(2):133-142
13 species of cestodes from 13 species of Philippine birds are reported from Palawan Island. Raillietina (R.) palawanensis n. sp., from Chalcophaps i. indica, has three or four testes, and a cirrus pouch 93 to 108 mum long, 28 to 45 mum wide, and its egg capsules are 10 to 12 mum long, seven to nine mum wide, each containing four to six eggs. Raillietina (R.) passeriformicola n. sp., from Gracula religiosa palawanensis, has seven to nine testes, and a cirrus poucch 134 to 170 mum long, 47 to 68 mum wide. Its egg capsules are 79 to 115 mum wide, containing 7 to 12 eggs each. Raillietina (R.) fischthali n. sp., from Ducula aenea palawanensis, has 12 to 15 testes, and a cirrus pouch 130 to 150 mum long, 52 to 72 mum wide. Its egg capsules are 130 to 200 mum wide each containing 50 to 70 eggs. Raillietina (R.) johri Ortlepp, 1938, is redescribed. Anonchotaenia chauhani Mukherjee, 1965 is shown to be a junior synonym of A. gaugi Singh, 1952. 相似文献
985.
S Mármol Navarro S Napal Lecumberri R Rajab J Guadalajara Jurado C Fachal Bermúdez 《Canadian Metallurgical Quarterly》1995,48(9):949-951
OBJECTIVE: The present study reviews the differential diagnosis of adrenal masses, including the uncommon forms, as the one described herein. METHOD/RESULTS: A patient with a giant adrenal mass that required differential diagnosis from other types of adrenal masses is presented. The diagnosis could only be made following anatomopathological analyses. CONCLUSIONS: The present case demonstrates that the uncommon forms of adrenal masses must be taken into account in the differential diagnosis, which, however, can only be confirmed by the pathological analysis since the findings on diagnostic imaging mimic other forms. 相似文献
986.
Reference has been made in the literature of the variability in the clinical presentation of deficiency of complex III of the respiratory chain, identifying up to the moment, four groups, the first of which is characterized by hipotonia and wearness starting at variable ages. We report a new case of mitochondrial myopathy due to deficiency of this complex and included within this first group, and consider the importance of defining the clinical and histochemical characteristics of this polymorphous entity. 相似文献
987.
988.
A pilot study of soluble adhesion molecules as surrogate markers for acute liver allograft rejection
VJ Navarro D Silver AN Langnas RS Markin AL Friedman JS Pober 《Canadian Metallurgical Quarterly》1998,65(1):126-130
OBJECTIVE: The purpose of this study was to determine the degree to which the number and angular disparity of component projections influence depth discrimination with tuned-aperture computed tomography. STUDY DESIGN: Groups of three tiny steel spheres served as fiducial references on and in four partially edentulous mandibles. Two spheres were attached to the facial and lingual surfaces of each mandible, and the third was fixed in the apical region of an open tooth socket. Errors in estimates of the depth of the apically positioned sphere relative to the other two spheres were determined from three-dimensional tuned-aperture computed tomography reconstructions. These data were compared with actual measurements produced independently with an optical micrometer. Multiple projections required by the tuned-aperture computed tomography reconstruction algorithm were produced from radially symmetric exposures bearing angular disparities of 5, 15, 30, and 45 degrees. The number of symmetrically dispersed projections per tuned-aperture computed tomography reconstruction likewise was varied systematically (2, 4, 8, 12, and 16 projections). These variables were manipulated through the use of a balanced factorial design. Depth estimates were performed by trained observers; the estimates were based on the determination of tuned-aperture computed tomography slices perceived as imaging the respective apical spheres in sharpest focus. Specimen and observer effects were also considered as independent variables. Resulting data were normalized by logarithmic transformation and analyzed statistically by analysis of variance. RESULTS: Significant differences (p < 0.005) were demonstrated for angular disparity and specimen effects, but the number of projections and the effect of the observer were not found to be statistically significant. CONCLUSIONS: In dentistry, angular disparities of 15 degrees or greater should be used when tuned-aperture computed tomography is being applied to diagnostic tasks requiring maximal depth discrimination accuracy. 相似文献
989.
Physicochemical Degradation of Titania-Stabilized Soluble Phosphate Glasses for Medical Applications
Melba Navarro Maria-Pau Ginebra Jerome Clément Martínez Salvador Avila Gloria Josep A. Planell 《Journal of the American Ceramic Society》2003,86(8):1345-1352
Four different formulations of phosphate glasses in the system P2 O5 –CaO–Na2 O–TiO2 were developed. Their physicochemical, morphologic, and structural evolution was analyzed during in vitro degradation in SBF (simulated body fluid) at 37°C up to 16 weeks. The results showed that the addition of TiO2 into the glass system enhanced both the elastic modulus and the chemical durability of the glasses. Indeed, the elastic modulus increased from 66.6 to 75.95 GPa and the weight loss percentage diminished from 1.6% to 0.3% with the addition of 8 mol% TiO2 . A uniform and superficial degradation mechanism could be observed throughout the dissolution time by means of environmental scanning electron microscopy (ESEM), inductively coupled plasma mass spectroscopy (ICP-MS), and Raman spectroscopy. The degradation process undergone by these glasses allows them to maintain their mechanical properties during the degradation process. Therefore, these materials offer an interesting choice for slowly resorbable materials in biomedical applications. 相似文献
990.
N Marín Gámez H Kessel Sardi?as G López Martínez A Barnosi Marín J Montoya Vergel A Navarro Corral M Delgado Rodríguez 《Canadian Metallurgical Quarterly》1998,15(7):349-352
Although tetanus is a preventable disease, several cases are reported to the Centers for Disease Control and Prevention each year. Many conditions treated by podiatric physicians carry the risk of infection by Clostridium tetani, and it is advisable for podiatrists to update a patient's tetanus immunization status if the patient presents with a tetanus-prone wound. 相似文献