全文获取类型
收费全文 | 2983篇 |
免费 | 53篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 26篇 |
综合类 | 1篇 |
化学工业 | 235篇 |
金属工艺 | 24篇 |
机械仪表 | 92篇 |
建筑科学 | 30篇 |
矿业工程 | 6篇 |
能源动力 | 33篇 |
轻工业 | 143篇 |
水利工程 | 6篇 |
石油天然气 | 14篇 |
无线电 | 73篇 |
一般工业技术 | 137篇 |
冶金工业 | 2115篇 |
原子能技术 | 8篇 |
自动化技术 | 97篇 |
出版年
2023年 | 9篇 |
2022年 | 18篇 |
2021年 | 35篇 |
2020年 | 26篇 |
2019年 | 33篇 |
2018年 | 29篇 |
2017年 | 43篇 |
2016年 | 35篇 |
2015年 | 24篇 |
2014年 | 31篇 |
2013年 | 82篇 |
2012年 | 45篇 |
2011年 | 41篇 |
2010年 | 56篇 |
2009年 | 63篇 |
2008年 | 43篇 |
2007年 | 32篇 |
2006年 | 40篇 |
2005年 | 30篇 |
2004年 | 24篇 |
2003年 | 18篇 |
2002年 | 28篇 |
2001年 | 18篇 |
2000年 | 27篇 |
1999年 | 85篇 |
1998年 | 636篇 |
1997年 | 377篇 |
1996年 | 243篇 |
1995年 | 149篇 |
1994年 | 105篇 |
1993年 | 130篇 |
1992年 | 21篇 |
1991年 | 24篇 |
1990年 | 19篇 |
1989年 | 21篇 |
1988年 | 27篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 19篇 |
1984年 | 2篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 23篇 |
1980年 | 27篇 |
1978年 | 6篇 |
1977年 | 68篇 |
1976年 | 165篇 |
1975年 | 4篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有3040条查询结果,搜索用时 15 毫秒
11.
AG Martov VIa Simonov BM Krendel'' SS Zenkov SA Moskalenko 《Canadian Metallurgical Quarterly》1993,38(3):16-19
Hyperferremia is shown to affect antioxidant system of the body, oxidation-reduction reactions in the cells seen as shifts in lymphocyte chemiluminescence. Dynamic changes in lymphocyte chemiluminescence reflect the level of hyperferremia. 相似文献
12.
AG Shankar S Ashley M Radford A Barrett D Wright CR Pinkerton 《Canadian Metallurgical Quarterly》1997,15(7):2622-2630
PURPOSE: Histology has been identified as an important prognostic factor in Hodgkin's disease (HD) in adults. Information regarding the impact of histology on outcome in childhood HD is scarce. This study determines the effect of histology on the overall survival (OS) or progression-free survival (PFS) in a national series of children treated in a standardized manner. PATIENTS AND METHODS: The results of treatment of 331 assessable patients, treated between January 1, 1982 and June 30, 1992, in the United Kingdom Children's Cancer Study Group (UKCCSG) Hodgkin's study I were reviewed to evaluate OS, PFS, and deaths according to stage and histology. Treatment was either involved-field radiation alone (stage IA) or chlorambucil, vinblastine, procarbazine, and prednisolone (ChlVPP) chemotherapy with or without mediastinal radiation. All were clinically staged at diagnosis. RESULTS: Nodular sclerosing (NS) HD was the most common histologic subtype (155 of 331 patients [47%]) and was uniformly distributed through all stages. Lymphocyte-depletion (LD) HD was extremely uncommon (< 1%). Mixed-cellularity (MC) HD had the highest relapse rate, but this was only significant (P < .05) in stage I patients who received local irradiation alone. There was no other statistically significant difference in OS and PFS between the various histologic subtypes. Multivariate analysis for PFS and OS confirmed that stage was the most important prognostic factor and that histology did not have an effect after stratification by stage. CONCLUSION: This study demonstrates that with effective multiagent chemotherapy, histologic subtype does not influence outcome. The high relapse rates in stage I MC subtype indicates that MC HD is biologically aggressive and systemic treatment with or without local irradiation may be indicated. The high relapse rate in stage IV patients appeared to be independent of histology. 相似文献
13.
Obesity is a major risk factor for cardiovascular disease. However, a direct link between these two states is difficult to establish, since obesity frequently occurs with other disease states such as diabetes, hypertension and atherosclerosis. Clinical studies have clearly shown that uncorrected obesity is associated with cardiac hypertrophy and compromised ventricular function. A number of rodent models of obesity have been studied in terms of cardiovascular adaptations. Cardiac function of the obese Zucker rat appears to be normal at a younger age. Only after several months is depression in cardiac function discernable. These animals are mildly hypertensive, but do not exhibit the characteristic increase in cardiac output associated with human obesity. A unique characteristic of JCR:LA-cp rat is that they develop atherosclerotic and myocardial lesions. Hearts from these animals will maintain normal function when perfused with physiological levels of calcium. At higher calcium concentrations, however, mechanical function becomes impaired. Dietary-induced obese rats exhibit many of the hemodynamic alterations associated with human obesity, but there is no evidence to-date that these animals will develop severe cardiac depression. Short-term weight reduction apparently has beneficial cardiovascular effects, but weight cycling may be harmful. Given the widespread occurrence of obesity, further studies are warranted to characterize the cardiac manifestations of this condition. 相似文献
14.
15.
16.
17.
18.
19.
F. R. Perioto M. E. T. Alvarez W. A. Araujo M. R. Wolf‐Maciel R. Maciel Filho 《应用聚合物科学杂志》2008,110(6):3544-3551
A new calculation procedure for free‐volume parameters is considered in this work by using viscosity prediction methods and the Levenberg‐Marquardt calculation scheme. All parameters used in the Vrentas–Duda free‐volume theory can be estimated from pure component properties. The prediction results are compared with experimental data for some polymer/solvent systems. The diffusion coefficient calculated by Vrentas–Duda theory can be used in the modeling of membrane separation processes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
20.
We report a case of typical chronic eosinophilic pneumonia (CEP), in a female of 27 years-old suffering bronchial asthma light. Although the initial answer to the treatment with steroids was satisfactory, the patient develop difficult to control asthma (DCA). DCA is a clinical situation which requires careful investigation of several potential factors which can be solved. We suggest a protocol of treatment for patients affected with DCA. 相似文献