全文获取类型
收费全文 | 488篇 |
免费 | 14篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 3篇 |
综合类 | 3篇 |
化学工业 | 18篇 |
金属工艺 | 18篇 |
机械仪表 | 7篇 |
建筑科学 | 19篇 |
矿业工程 | 2篇 |
能源动力 | 3篇 |
轻工业 | 69篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 23篇 |
一般工业技术 | 18篇 |
冶金工业 | 297篇 |
自动化技术 | 33篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 43篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 11篇 |
2007年 | 10篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 70篇 |
1997年 | 64篇 |
1996年 | 34篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 19篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1977年 | 9篇 |
1976年 | 35篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1959年 | 2篇 |
1957年 | 2篇 |
1956年 | 3篇 |
排序方式: 共有515条查询结果,搜索用时 390 毫秒
31.
32.
33.
A total of 29 volatile nitrogen-containing compounds were identified from model systems containing glutamine, glutamic acid, asparagine and aspartic acid, respectively, with glucose under simulated deep-fat frying conditions in corn oil. Alkylpyrazines were the most important flavor compound generated. Glutamine, which released free ammonia easily under this condition gave the highest yield of alkylpyrazines. The profiles of pyrazines produced by each amino acid were significantly different. In a glutamine system, 2-(2-furyl)pyrazine, 2-(2-furyl)- 5-methylpyrazine and 2-(2-furyl)-6-methylpyrazine were the major compounds generated. 相似文献
34.
35.
36.
Volatile flavor compounds were isolated from 70 kg of freshly roasted Florida Runner peanuts by a specially designed apparatus. The isolated volatile flavor compounds were subjected to extensive gas chromatographic fractionation and the pure fractions obtained were identified by infrared and mass spectrometry. A total of 131 compounds was identified. The following compounds are reported for the first time as flavor components of roasted peanuts: five lactones, incluing γ-crotolactone, 3-methyl-γ-crotolactone and 5-hydroxy-4-nonenoic acid, lactone; four pyrazines, three pyrroles; three pyridines, 13 sulfides, including three monosulfides, six disulfides and four trisulfides; seven thiazoles, two thiophenes, five furanoids, including 2-methyL3(2H)furanone; five oxazoles, three oxazolines, including 2-methyl-3-oxazoline; 12 hydrocarbons, one alcohol, one ketone, two acids, two esters, 2-acetoxy-2-butene, and maltol. 相似文献
37.
A multi-pass laminar counterflow cooler or heater is an open duct divided into four subchannels with uniform wall temperature by inserting three impermeable sheets. Only the temperature of the flow stream varies along the subchannels. Improvements in heat transfer efficiency were investigated analytically with the use of eigenfunction expansions in the power series. The enhancement results in heat-transfer efficiency for two multi-pass devices (flow pattern A and flow pattern B) are represented graphically and compared with those in a single-pass device (without three impermeable sheets inserted) and those in a double-pass device (only one impermeable sheet inserted). Analytical results show that suitable impermeable-sheet position adjustments can effectively enhance heat transfer efficiencies for two multi-pass devices (flow pattern A and flow pattern B) compared with the efficiencies of single and double-pass devices. 相似文献
38.
HOAgraveNG XUÂN PHÚ 《International journal of control》2013,86(5):1867-1882
We solve a linear optimal control problem with state and control restrictions by the method of region analysis, where the state equations describe the flow in a directed graph without a circuit. The results are used for the optimal control of a system of hydroelectric power plants. 相似文献
39.
H Kappauf WM Gallmeier PH Wünsch HO Mittelmeier J Birkmann G Büschel G Kaiser J Kraus 《Canadian Metallurgical Quarterly》1997,8(10):1031-1039
Spontaneous remission of cancer (SR) is defined as a complete or partial, temporary or permanent disappearance of all or at least some relevant parameters of a soundly diagnosed malignant disease without any medical treatment or with treatment that is considered inadequate to produce the resulting regression. We report the case of a 61-year-old man who presented with extensive metatastic disease five months after pneumonectomy for poorly differentiated large cell and polymorphic lung cancer. A vast metastatic tumour mass of the abdominal wall was confirmed histolologically and there was clinical and radiographic evidence of liver and lung metastases. Eight months later, the patient was operated on for a hernia, which had developed in the inguinal biopsy scar and the surgeon confirmed complete clinical SR of the abdominal wall metastases. Again five months later there was no longer any radiologic evidence of liver and lung metastases. Complete remission has persisted more than five years. Histology of the primary and of the abdominal metastases were reviewed by several independent pathologists. SR is an extremly rare event in lung cancer. This is the first documented case of clinically evident visceral metastases of a bronchiogenic adenocarcinoma developing after complete resection of the primary and then showing complete SR. The epidemiology of SR is reviewed and possible mechanisms involved in SR are discussed. 相似文献
40.
O Dewald T Fischlein HO Vetter C Schmitz O G?dje P G?hring B Reichart 《Canadian Metallurgical Quarterly》1997,12(4):634-641
OBJECTIVE: Mechanical circulatory support is a therapy for patients with end stage cardiac insufficiency. The thromboembolic events are feared complications during support, due to the surface thrombogenicity of the implanted device. Activated blood platelets play a major role in this context. Consequently the platelet morphology of patients was investigated. METHODS: Platelets of eight patients were observed by means of scanning electron microscopy during the period of support with the Novacor left ventricular assist system N100. Blood was collected preoperatively and daily during the first week as well as weekly during the first 3 months. Samples were fixed with cacodylic-acid buffered glutaraldehyde. Platelet alterations were classified as non-activated, activated and aggregated, based on the so-called 'shape change' morphology. In addition, blood coagulation parameters were evaluated (e.g. activated partial thromboplastin time, prothrombin time, antithrombin III). RESULTS: Preoperatively, 15.0 +/- 4.6% (overall mean values) of activated platelets were found. Within the first postoperative week, the mean level of activated platelets increased to 32.8 +/- 8.0% (P < 0.05). Comparing short- (< 30 days; n = 4) vs. long-period (> 30 days; n = 4) support, a significant difference of activated platelets was evaluated (24.3 +/- 3.3% vs. 34.8 +/- 3.4%, P = 0.004). A correlation was found between the values of activated clotting time and activated platelets. Specific platelet deformations and damages appeared during support, which could not be found preoperatively. CONCLUSIONS: The platelet morphology showed alterations in all patients probably most strongly induced by the surface activation of the implanted device. These observations should be taken into consideration in management of postoperative anticoagulation therapy. 相似文献