全文获取类型
收费全文 | 3405篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 31篇 |
综合类 | 2篇 |
化学工业 | 75篇 |
金属工艺 | 15篇 |
机械仪表 | 12篇 |
建筑科学 | 30篇 |
能源动力 | 16篇 |
轻工业 | 43篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 141篇 |
一般工业技术 | 99篇 |
冶金工业 | 2789篇 |
原子能技术 | 6篇 |
自动化技术 | 152篇 |
出版年
2022年 | 5篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2014年 | 11篇 |
2013年 | 27篇 |
2012年 | 29篇 |
2011年 | 27篇 |
2010年 | 13篇 |
2009年 | 18篇 |
2008年 | 30篇 |
2007年 | 32篇 |
2006年 | 24篇 |
2005年 | 23篇 |
2004年 | 25篇 |
2003年 | 37篇 |
2002年 | 26篇 |
2001年 | 21篇 |
2000年 | 19篇 |
1999年 | 116篇 |
1998年 | 901篇 |
1997年 | 516篇 |
1996年 | 297篇 |
1995年 | 171篇 |
1994年 | 153篇 |
1993年 | 176篇 |
1992年 | 30篇 |
1991年 | 37篇 |
1990年 | 36篇 |
1989年 | 42篇 |
1988年 | 49篇 |
1987年 | 53篇 |
1986年 | 29篇 |
1985年 | 37篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 24篇 |
1981年 | 14篇 |
1980年 | 39篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 69篇 |
1976年 | 127篇 |
1975年 | 10篇 |
1974年 | 14篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1968年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有3413条查询结果,搜索用时 0 毫秒
61.
62.
63.
64.
A high capacity gel filtration system was developed with the purpose of isolating factor VIII (FVIII) and von Willebrand factor (vWF) directly from plasma in significantly higher yields than obtained by cryoprecipitation, the technique most commonly used to recover FVIII-vWF from human plasma. After laboratory-scale gel filtration of plasma, a FVIII-containing fraction was collected containing about 90% of FVIII in the applied plasma and with almost tenfold higher purity than that obtained by cryoprecipitation. The gel filtration step has been scaled up for use as the initial step in the manufacturing process for a FVIII preparation (Nordiate). 相似文献
65.
Three cheetahs (Acinonyx jubatus) had a clinical history of chronic spiral bacteria-associated gastritis and three cheetahs had no clinical history of gastritis. Gastric biopsies were obtained from all six cheetahs prior to treatment for gastritis and 3 wk and 1 yr posttreatment. The cheetahs were treated with tetracycline hydrochloride 500 mg p.o. q.i.d., metronidazole 250 mg p.o. q.i.d., and bismuth subsalicylate 300 mg p.o. q.i.d. Each drug was administered concurrently for 7 days. Following this treatment, each cheetah was maintained on 300 mg bismuth subsalicylate p.o. s.i.d. for 1 yr. The three cheetahs with a history of gastritis were culture positive for Helicobacter acinonyx and remained positive during the entire study. The three cheetahs with no clinical history of gastritis were culture negative for H. acinonyx, but gastric biopsies revealed Gastrospirillum-like bacteria (tentatively named Helicobacter heilmannii) pretreatment. Gastric biopsies were negative for H. heilmannii on subsequent examinations. Although the treatment did not eradicate H. acinonyx, it did provide symptomatic relief from the vomiting, anorexia, and weight loss associated with clinical gastritis. The use of endoscopically guided gastric mucosal biopsies for urease testing and histopathologic examination of Warthin-Starry-stained sections is a sensitive and specific method of diagnosing spiral bacteria-associated gastritis. Treatment of spiral bacteria-associated gastritis in cheetahs should include the rational use of antibiotics (tetracycline or amoxicillin and metronidazole), bismuth compounds, and omeprazole and evaluation of husbandry methods to reduce stress. 相似文献
66.
KA Keay LJ Crowfoot NS Floyd LA Henderson MJ Christie R Bandler 《Canadian Metallurgical Quarterly》1997,762(1-2):61-71
Differentiating the binding properties of applied lectins should facilitate the selection of lectins for characterization of glycoreceptors on the cell surface. Based on the binding specificities studied by inhibition assays of lectin-glycan interactions, over twenty Gal and/or GalNAc specific lectins have been divided into eight groups according to their specificity for structural units (lectin determinants), which are the disaccharide as all or part of the determinants and of GalNAc alpha 1-->Ser (Thr) of the peptide chain. A scheme of codes for lectin determinants is illustrated as follows: (1) F (GalNAc alpha 1-->3GalNAc), Forssman specific disaccharide--Dolichos biflorus (DBL), Helix pomatia (HPL) and Wistaria floribunda (WFL) lectins. (2) A (GalNAc alpha 1-->3 Gal), blood group A specific disaccharide--Codium fragile subspecies tomentosoides (CFT), Soy bean (SBL), Vicia villosa-A4 (VVL-A4), and Wistaria floribunda (WFL) lectins. (3) Tn (GalNAc alpha 1-->Ser (Thr) of the protein core)--Vicia villosa B4 (VVL-B4), Salvia sclarea (SSL), Maclura pomifera (MPL), Bauhinia purpurea alba (BPL) and Artocarpus integrifolia (Jacalin, AIL). (4) T (Gal beta 1-->3GalNAc), the mucin type sugar sequences on the human erythrocyte membrane(T alpha), T antigen or the disaccharides at the terminal nonreducing end of gangliosides (T beta)--Peanut (PNA), Bauhinia purpurea alba (BPL), Maclura pomifera (MPL), Sophora japonica (SJL), Artocarpus lakoocha (Artocarpin) lectins and Abrus precatorius agglutinin (APA).(5) I and II (Gal beta 1-->3(4)GlcNAc)--the disaccharide residue at the nonreducing end of the carbohydrate chains derived from either N- or O-glycosidic linkage--Ricinus communis agglutinin (RCA1), Datura stramonium (TAL, Thorn apple), Erythrina cristagalli (ECL, Coral tree), and Geodia cydonium (GCL). (6) B (Gal alpha 1-->3Gal), human blood group B specific disaccharide--Griffonia(Banderiaea) simplicifolia B4 (GSI-B4). (7) E (Gal alpha 1-->4Gal), receptors for pathogenic E. coli agglutinin, Shiga toxin and Mistletoe toxic lectin-I (ML-I) and abrin-a. 相似文献
67.
68.
A. Ye. Valamin A. Yu. Kultyshev V. N. Bilan A. A. Goldberg Yu. A. Sakhnin M. V. Shekhter H. C. Paneque Aguilera M. Yu. Stepanov T. L. Shibaev Ye. N. Polyaeva 《Thermal Engineering》2012,59(12):893-899
This paper describes the design of the steam turbine intended for a single-unit two-shaft combined-cycle plant and its main systems, the heat flow diagram, and turbine plant arrangement. The turbine should operate as part of the combined-cycle power plant that will be constructed on the basis of the modern PG6111FA gas turbine manufactured in the USA. 相似文献
69.
Yalcin A. Popat K.C. Aldridge J.C. Desai T.A. Hryniewicz J. Chbouki N. Little B.E. Oliver King Van V. Sai Chu Gill D. Anthes-Washburn M. Unlu M.S. Goldberg B.B. 《IEEE journal of selected topics in quantum electronics》2006,12(1):148-155
A biosensor application of vertically coupled glass microring resonators with Q/spl sim/12 000 is introduced. Using balanced photodetection, very high signal to noise ratios, and thus high sensitivity to refractive index changes (limit of detection of 1.8/spl times/10/sup -5/ refractive index units), are achieved. Ellipsometry and X-ray photoelectron spectroscopy results indicate successful modification of biosensor surfaces. Experimental data obtained separately for a bulk change of refractive index of the medium and for avidin-biotin binding on the ring surface are reported. Excellent repeatability and close-to-complete surface regeneration after binding are experimentally demonstrated. 相似文献
70.
Mercado L.L. Goldberg C. Kuo S.-M. Tien-Yu Tom Lee Pozder S.K. 《Device and Materials Reliability, IEEE Transactions on》2003,3(4):111-118
An interfacial-fracture-mechanics-based simulation methodology has been developed to study the flip-chip packaging effect on the copper/low-k structures. Multilevel submodeling techniques have been used to bridge the scale difference between the flip-chip packages and the metal/dielectric stacks. To achieve a smaller feature size and higher speed in future chips, SiO/sub 2/ can be replaced with low-k dielectric material in all via and trench layers or the number of metal layers can be increased. The effect of both packaging options has been evaluated. With either option, the future flip-chip copper/low-k packages are facing higher possibilities of adhesive or cohesive failure near the low-k interface. This paper provides a quantitative evaluation of the increased risk, thus providing guidelines to the next level of low-k flip-chip packages. 相似文献