全文获取类型
收费全文 | 804篇 |
免费 | 0篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 11篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 3篇 |
轻工业 | 6篇 |
无线电 | 9篇 |
一般工业技术 | 11篇 |
冶金工业 | 754篇 |
原子能技术 | 1篇 |
自动化技术 | 3篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2013年 | 9篇 |
2012年 | 4篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 17篇 |
1998年 | 215篇 |
1997年 | 154篇 |
1996年 | 85篇 |
1995年 | 49篇 |
1994年 | 46篇 |
1993年 | 52篇 |
1992年 | 5篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 10篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 26篇 |
1976年 | 60篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有804条查询结果,搜索用时 15 毫秒
41.
42.
43.
PJ Hofschire EP Todd RL Varco EL Kaplan JE Edwards 《Canadian Metallurgical Quarterly》1976,69(3):439-440
We report an unusual case in which an apparently normal upper lobe of the right lung was supplied by major systemic arterial and pulmonary arterial vessels. The anomalous artery arose from the descending aorta. Following interruption of this vessel, the machinery-like murmur previously present disappeared. 相似文献
44.
Ryan N. Smith Monique Chyba George R. Wilkens Christopher J. Catone 《International journal of control》2013,86(9):1641-1656
The main focus of this article is the motion planning problem for a deeply submerged rigid body. The equations of motion are formulated and presented by use of the framework of differential geometry and these equations incorporate external dissipative and restoring forces. We consider a kinematic reduction of the affine connection control system for the rigid body submerged in an ideal fluid, and present an extension of this reduction to the forced affine connection control system for the rigid body submerged in a viscous fluid. The motion planning strategy is based on kinematic motions; the integral curves of rank one kinematic reductions. This method is of particular interest to autonomous underwater vehicles which cannot directly control all six degrees of freedom (such as torpedo-shaped autonomous underwater vehicles) or in case of actuator failure (i.e. under-actuated scenario). A practical example is included to illustrate our technique. 相似文献
45.
46.
K Rithidech VP Bond EP Cronkite MH Thompson JE Bullis 《Canadian Metallurgical Quarterly》1995,92(4):1152-1156
In an effort to identify the precise role of a deletion at regions D-E of mouse chromosome 2 [del2(D-E)] during the development of radiation-induced myeloid leukemia, we conducted a serial sacrifice study in which metaphase chromosomes were examined by the G-banding technique. Such metaphase cells were collected from x-irradiated mice during the period of transformation of some of the normal hematopoietic cells to the fully developed leukemic phenotype. A group of 250 CBA/Ca male mice (10-12 weeks old) were exposed to a single dose of 2 Gy of 250-kilovolt-peak x-rays; 42 age-matched male mice served as controls. Groups of randomly selected mice were sacrificed at 20 hr, 1 week, and then at intervals of 3 months up to 24 months after x-irradiation. Slides for cytogenetic, hematological, and histological examination were prepared for each animal at each sacrifice time. An expansion of cells with lesions on one copy of chromosome 2 was evident in 20-25% of treated mice at each sacrifice time. The majority of such lesions were translocations at 2F or 2H, strongly suggesting hypermutability of these sites on mouse chromosome 2. No lesions were found in control mice. The finding leads to the possibility that genomic lesions close to 2D and 2E are aberrants associated with radiation leukemogenesis, whereas a single clone of cells with a del2(D-E) may lead directly to overt leukemia. The data also indicate that leukemic transformation arises from the cumulative effects of multiple genetic events on chromosome 2, reinforcing the thesis that multiple steps of mutation occur in the pathogenesis of cancer. 相似文献
47.
ME Bertrand V Legrand J Boland E Fleck J Bonnier H Emmanuelson M Vrolix L Missault S Chierchia M Casaccia L Niccoli A Oto C White M Webb-Peploe E Van Belle EP McFadden 《Canadian Metallurgical Quarterly》1998,98(16):1597-1603
BACKGROUND: Dual therapy with ticlopidine and aspirin has been shown to be as effective as or more effective than conventional anticoagulation in patients with an optimal result after implantation of intracoronary metallic stents. However, the safety and efficacy of antiplatelet therapy alone in an unselected population has not been evaluated. METHODS: Patients were randomized to conventional anticoagulation or to treatment with antiplatelet therapy alone. Indications for stenting were classified as elective (decided before the procedure) or unplanned (to salvage failed angioplasty or to optimize the results of balloon angioplasty). After stenting, patients received aspirin and either ticlopidine or conventional anticoagulation (heparin or oral anticoagulant). The primary end point was the occurrence of bleeding or peripheral vascular complications; secondary end points were cardiac events (death, infarction, or stent occlusion) and duration of hospitalization. RESULTS: In 13 centers, 236 patients were randomized to anticoagulation and 249 to antiplatelet therapy. Stenting was elective in 58% of patients and unplanned in 42%. Stent implantation was successfully achieved in 99% of patients. A primary end point occurred in 33 patients (13.5%) in the antiplatelet group and 48 patients (21%) in the anticoagulation group (odds ratio=0.6 [95% CI 0.36 to 0.98], P=0.03). Major cardiac-related events in electively stented patients were less common (odds ratio=0.23 [95% CI 0.05 to 0.91], P=0.01) in the antiplatelet group (3 of 123, 2.4%) than the anticoagulation group (11 of 111, 9.9%). Hospital stay was significantly shorter in the antiplatelet group (4.3+/-3.6 versus 6. 4+/-3.7 days, P=0.0001). CONCLUSIONS: Antiplatelet therapy after coronary stenting significantly reduced rates of bleeding and subacute stent occlusion compared with conventional anticoagulation. 相似文献
48.
EL Nazarenko RP Gorshkova VA Zubkov AS Shashkov EP Ivanova IuS Ovodov 《Canadian Metallurgical Quarterly》1993,19(7):733-739
An acidic polysaccharide from Alteromonas sp. 4MC17 is built up of trisaccharide repeating units containing D-glucose, D-mannose and D-galacturonic acid residues. On the basis of methylation studies, 1H and 13C NMR-spectroscopy data, including two-dimensional homonuclear correlation spectroscopy and nuclear Overhauser effects, the following structure was suggested for the polysaccharide repeating unit: -->4)-beta-D-Glcp-(1-->4)-beta-D-GalpA-(1-->4)-beta-D-Manp-( 1-->. 相似文献
49.
JM Lablanche EP McFadden N Meneveau JR Lusson B Bertrand JP Metzger V Legrand G Grollier C Macaya B de Bruyne A Vahanian A Grentzinger C Masquet JE Wolf G Tobelem S Fontecave A Vacheron P d'Azemar ME Bertrand 《Canadian Metallurgical Quarterly》1997,96(10):3396-3402
BACKGROUND: Experimental studies suggest that the antiproliferative effect of heparin after arterial injury is maximized by pretreatment. No previous studies of restenosis have used a pretreatment strategy. We designed this study to determine whether treatment with nadroparin, a low-molecular-weight heparin, started 3 days before the procedure and continued for 3 months, affected angiographic restenosis or clinical outcome after coronary angioplasty. METHODS AND RESULTS: In a prospective multicenter, double-blind, randomized trial, elective coronary angioplasty was performed on 354 patients who were treated with daily subcutaneous nadroparin (0.6 mL of 10,250 anti-Xa IU/mL) or placebo injections started 3 days before angioplasty and continued for 3 months. Angiography was performed just before and immediately after angioplasty and at follow-up. The primary study end point was angiographic restenosis, assessed by quantitative coronary angiography 3 months after balloon angioplasty. Clinical follow-up was continued up to 6 months. Clinical and procedural variables and the occurrence of periprocedural complications did not differ between groups. At angiographic follow-up, the mean minimal lumen diameter and the mean residual stenosis in the nadroparin group (1.37+/-0.66 mm, 51.9+/-21.0%) did not differ from the corresponding values in the control group (1.48+/-0.59 mm, 48.8+/-18.9%). Combined major cardiac-related clinical events (death, myocardial infarction, target lesion revascularization) did not differ between groups (30.3% versus 29.6%). CONCLUSIONS: Pretreatment with the low-molecular-weight heparin nadroparin continued for 3 months after balloon angioplasty had no beneficial effect on angiographic restenosis or on adverse clinical outcomes. 相似文献
50.
Medical definitions of occupational and professionally conditioned pathology are given in the article together with relevant examples. With the view to account appropriately occupational pathology in accordance with its severity classification based on the degree of working capacity loss is presented. Notions of acute occupational disease (intoxication) and professional accident are determined. International list of occupational diseases is considered. Suggestions intended at promotion of safe working conditions are made on perfection of the Ukrainian list. 相似文献