全文获取类型
收费全文 | 446篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 88篇 |
金属工艺 | 10篇 |
机械仪表 | 11篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 12篇 |
轻工业 | 77篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 21篇 |
一般工业技术 | 74篇 |
冶金工业 | 108篇 |
原子能技术 | 6篇 |
自动化技术 | 34篇 |
出版年
2023年 | 4篇 |
2022年 | 11篇 |
2021年 | 18篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 4篇 |
2014年 | 16篇 |
2013年 | 19篇 |
2012年 | 18篇 |
2011年 | 20篇 |
2010年 | 14篇 |
2009年 | 17篇 |
2008年 | 16篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 42篇 |
1997年 | 25篇 |
1996年 | 22篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1971年 | 2篇 |
1963年 | 2篇 |
1930年 | 1篇 |
排序方式: 共有463条查询结果,搜索用时 31 毫秒
91.
Experimental and numerical analysis of natural ventilation with combined light/vent pipes 总被引:2,自引:0,他引:2
Armando C. Oliveira Ant nio R. Silva Clito F. Afonso Szabolcs Varga 《Applied Thermal Engineering》2001,21(18):1925-1936
Both experimental and numerical procedures were developed for studying natural ventilation in combined light/vent pipes. An experimental tracer gas technique was used to measure ventilation rates in a test cell. Two different pipe terminals were simultaneously used, dividing the cell in two identical volumes, in order to allow a direct comparison of their performance. A 3D numerical model was developed using ansys5.5/flotran. Experimental and numerical results are shown and compared. It is concluded that pipe terminals significantly enhance ventilation, that one type of terminal has a better performance and that the numerical model underestimates measured flows. 相似文献
92.
Renta Szab Denise Brzsei Zsuzsanna Szab Alexandra Hoffmann Istvn Zupk Dniel Priksz Krisztina Kupai Csaba Varga Anik Psa 《International journal of molecular sciences》2020,21(22)
Endocannabinoids and their receptors are present in the cardiovascular system; however, their actions under different pathological conditions remain controversial. The aim of our study was to examine the effects of anandamide (AEA) on heme oxygenase (HO) and nitric oxide synthase (NOS) systems in an estrogen-depleted rat model. Sham-operated (SO) and surgically induced estrogen-deficient (OVX) female Wistar rats were used. During a two-week period, a group of OVX rats received 0.1 mg/kg estrogen (E2) per os, while AEA-induced alterations were analyzed after two weeks of AEA treatment at the dose of 1.0 mg/kg. At the end of the experiment, cardiac activity and expression of HO and NOS enzymes, content of cannabinoid 1 receptor, as well as concentrations of transient potential vanilloid 1 (TRPV1) and calcitonin gene-related peptide (CGRP) were measured. Our results show that estrogen withdrawal caused a significant decrease in both NOS and HO systems, and a similar tendency was observed regarding the TRPV1/CGRP pathway. Two weeks of either AEA or E2 treatment restored the adverse changes; however, the combined administration of these two molecules did not result in a further improvement. In light of the potential relationship between AEA and HO/NOS systems, AEA-induced upregulation of HO/NOS enzymes may be a therapeutic strategy in estrogen-deficient conditions. 相似文献
93.
Dr. Justin A. Shapiro Dr. John J. Varga Dr. Derek Parsonage William Walton Prof. Dr. Matthew R. Redinbo Larry J. Ross E. Lucile White Dr. Robert Bostwick Prof. Dr. William M. Wuest Prof. Dr. Al Claiborne Prof. Dr. Joanna B. Goldberg 《ChemMedChem》2019,14(1):78-82
Antibiotics with novel mechanisms of action are desperately needed to combat the increasing rates of multidrug-resistant infections. Bacterial pantothenate kinase (PanK) has emerged as a target of interest to cut off the biosynthesis of coenzyme A. Herein we report the results of an in vitro high-throughput screen of over 10 000 small molecules against Bacillus anthracis PanK, as well as a follow-up screen of hits against PanK isolated from Pseudomonas aeruginosa and Burkholderia cenocepacia. Nine hits are structurally categorized and analyzed to set the stage for future drug development. 相似文献
94.
E Luegmayr F Varga T Frank P Roschger K Klaushofer 《Canadian Metallurgical Quarterly》1996,18(6):591-599
We investigated the effects of thyroid hormone treatment on morphology, growth behaviour, and cytoskeletal structures of long-term cultured MC3T3-E1 cells. Morphological investigations were carried out on native cells by phase contrast microscopy and on epon-embedded semithin sections. The area covered by the cell and matrix layers (tissue-like area), percent extracellular matrix, average height of tissue-like area, and length and height of single cells were measured histomorphometrically on the cross sections. F-actin was analyzed histochemically and quantitated after fluorochrome-labeled phalloidin staining using confocal microscopy and fluorometry. Significant differences between control and T3-treated cells were found after confluency, but not in subconfluent cultures. Control cells continued to proliferate forming multilayers, and produced increasing amounts of extracellular matrix. In contrast, T3-treated cells stopped to proliferate forming two cell layers at the maximum. These cells were flattened, distinctly enlarged, and polygonal in shape. Histochemical staining for F-actin revealed three different staining patterns, depending on the position of the cell within the multilayer of control cultures. Basal cells contained a large number of thick stress fibers in parallel arrangement. Intermediate cells exhibited only a few thick actin filament bundles located at the outermost periphery. The superficial cells were characterized by a large number of thin, parallel-oriented microfilament bundles extending across the entire cytoplasm. The actin pattern of T3-treated cells resembled that of the basal cell layer of the control cells. The amount of F-actin increased with the prolonged T3 treatment. We conclude from these data that the known specific cellular responses to T3 treatment are accompanied by significant morphological alterations indicating pivotal effects of thyroid hormones on osteoblastic differentiation. 相似文献
95.
Supermolecular structure of isotactic polypropylene 总被引:5,自引:0,他引:5
J. Varga 《Journal of Materials Science》1992,27(10):2557-2579
The crystalline structure, spherulitic crystallization and melting behaviour of isotactic polypropylene (iPP) is comprehensively reviewed, illustrated and discussed. It is demonstrated and summarized how the nucleation, development and growth of the different spherulites depend on the crystallization and melting conditions both in quiescent and sheared melt. Based on the results the microtexture development during real processing conditions is elucidated for selected examples. Several subjects of intense debate on the above topics are clarified using evidence from polarized optical micrography and differential scanning calorimetry. 相似文献
96.
AM Gamper RH Winger KR Liedl CA Sotriffer JM Varga RT Kroemer BM Rode 《Canadian Metallurgical Quarterly》1996,39(20):3882-3888
Using comparative molecular field analysis (CoMFA), three-dimensional quantitative structure-activity relationships were developed for 27 haptens which bind to the monoclonal antibody IgE(Lb4). In order to obtain an alignment for these structurally very diverse antigens, the compounds were docked to a previously modeled receptor structure using the automated docking program AUTODOCK (Goodsell, D.S.; Olson, A.J. Proteins: Struct., Funct., Genet. 1990, 8, 195-202). Remarkably, this alignment method yielded highly consistent QSAR models, as indicated by the corresponding cross-validated r2 values (0.809 for a model with carbon as probe atom, 0.773 for a model with hydrogen as probe atom). Conventional alignment failed in providing a basis for self-consistent CoMFAs. Amino acids Tyr H 50, Tyr H 52, and Trp H 95 of the receptor appeared to be of crucial importance for binding of various antigens. These findings are consistent with earlier considerations of aromatic residues being responsible for the multispecificity of certain immunoglobulins. 相似文献
97.
A rotating magnetic field model of the axial induction motor is developed relating the geometric properties of the stator/rotor core. The main geometric dimensions of different type induction motors are compared using the field model formulas. An axial induction motor constant is derived from the output power formula. A new expression for the output power per unit volume is achieved by means of main dimensions and construction modification. A flowchart with stationary input data anticipates the assigned computed parameters of the axial induction motor. 相似文献
98.
Imre A. Varga E. Ji L. Ilic B. Metlushko V. Csaba G. Orlov A. Bernstein G.H. Porod W. 《IEEE transactions on magnetics》2006,42(11):3641-3644
Ferromagnetic ring elements on the micrometer and submicrometer scale exhibit flux-closure magnetic vortex states in an intermediate step of their magnetization reversal. These clockwise or counterclockwise flux-closure states are of interest for applications that encode binary information in magnetic elements. Here, we study the magnetization reversal process of triangular cobalt rings made by e-beam lithography and lift-off. We demonstrate that full control over the direction of flux-closure magnetic states can be achieved solely by homogeneous external magnetic fields applied in particular directions. We have extracted statistical experimental data pertaining to the range of critical field values that trigger magnetization reversal from magnetic force microscopy images, and we explain the results on the basis of micromagnetic simulations 相似文献
99.
100.
E Picano M Ostojic A Varga R Sicari A Djordjevic-Dikic I Nedeljkovic M Torres 《Canadian Metallurgical Quarterly》1996,27(6):1422-1428
OBJECTIVES: We sought to evaluate the effects of combined administration of infra-low dose dipyridamole and low dose dobutamine on assessment of myocardial viability. BACKGROUND: Low dose pharmacologic stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for the recognition of myocardial viability. METHODS: Thirty-four patients with rest wall motion dyssynergy by two-dimensional echocardiography and with angiographically proved coronary artery disease underwent in combination with two-dimensional echocardiographic monitoring: 1) low dose (5 to 10 microgram/kg per min over 3 min) dobutamine infusion; 2) infra-low dose (0.28 mg/kg over 4 min) dipyridamole infusion; 3) combination of infra-low dose dipyridamole infusion immediately followed by low dose dobutamine infusion (combined dipyridamole-dobutamine). RESULTS: Follow-up rest echocardiography was available in 30 patients. After revascularization, 82 segments showed a contractile improvement of > or = 1 grade, whereas 63 segments remained unchanged. The sensitivity of dobutamine, dipyridamole and combined dipyridamole-dobutamine for predicting recovery was 72% (95% confidence interval [CI] 60.9% to 81.3%), 67% (CI 55.8% to 77%) and 94% (CI 86.3% to 97.9%), respectively. The specificity of dipyridamole, dobutamine and combined dipyridamole-dobutamine was 95% (CI 86.7% to 99%), 92% (CI 82.4% to 97.3%) and 89% (CI 78.4% to 95.4%), respectively. The accuracy of the dobutamine, dipyridamole and combined dipyridamole-dobutamine test was 80%, 79% and 92%, respectively (combined dipyridamole-dobutamine vs. dobutamine, p < 0.05; combined dipyridamole-dobutamine vs. dipyridamole, p < 0.01). CONCLUSIONS: Infra-low dose dipyridamole added to low dose dobutamine recruits an inotropic reserve in asynergic segments that were nonresponders after either dobutamine or dipyridamole alone and destined to recover after revascularization. 相似文献