全文获取类型
收费全文 | 288690篇 |
免费 | 3133篇 |
国内免费 | 819篇 |
专业分类
电工技术 | 5042篇 |
综合类 | 163篇 |
化学工业 | 45673篇 |
金属工艺 | 11920篇 |
机械仪表 | 8653篇 |
建筑科学 | 6882篇 |
矿业工程 | 1839篇 |
能源动力 | 6756篇 |
轻工业 | 26108篇 |
水利工程 | 3202篇 |
石油天然气 | 7095篇 |
武器工业 | 16篇 |
无线电 | 31502篇 |
一般工业技术 | 57181篇 |
冶金工业 | 51471篇 |
原子能技术 | 7541篇 |
自动化技术 | 21598篇 |
出版年
2021年 | 2154篇 |
2018年 | 3720篇 |
2017年 | 3678篇 |
2016年 | 3955篇 |
2015年 | 2492篇 |
2014年 | 4268篇 |
2013年 | 12103篇 |
2012年 | 6894篇 |
2011年 | 9278篇 |
2010年 | 7619篇 |
2009年 | 8698篇 |
2008年 | 8975篇 |
2007年 | 8854篇 |
2006年 | 7858篇 |
2005年 | 7338篇 |
2004年 | 6825篇 |
2003年 | 6576篇 |
2002年 | 6661篇 |
2001年 | 6515篇 |
2000年 | 6188篇 |
1999年 | 6244篇 |
1998年 | 14795篇 |
1997年 | 11059篇 |
1996年 | 8583篇 |
1995年 | 6542篇 |
1994年 | 5930篇 |
1993年 | 5799篇 |
1992年 | 4480篇 |
1991年 | 4446篇 |
1990年 | 4289篇 |
1989年 | 4307篇 |
1988年 | 4257篇 |
1987年 | 3599篇 |
1986年 | 3598篇 |
1985年 | 4162篇 |
1984年 | 3966篇 |
1983年 | 3623篇 |
1982年 | 3422篇 |
1981年 | 3559篇 |
1980年 | 3422篇 |
1979年 | 3366篇 |
1978年 | 3448篇 |
1977年 | 3925篇 |
1976年 | 5041篇 |
1975年 | 3159篇 |
1974年 | 3007篇 |
1973年 | 3024篇 |
1972年 | 2651篇 |
1971年 | 2473篇 |
1970年 | 2104篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The knowledge-representation and compilation techniques used in a model-based, automatic software synthesis environment are discussed. The environment was used to build Caddmus, a system with more than 250 cooperating processes. The real-time execution environment automatically generates a macro-dataflow computation from declarative models. Central to the approach is the Multigraph Architecture, which provides the framework for model-based synthesis in real-time, parallel-computing environments. Application of Caddmus to analysis of all data related to testing new and redesigned turbine engines is described 相似文献
992.
993.
994.
Dyspnea and cyanosis are common presenting manifestations of cardiopulmonary disease. When these findings occur in a cigarette smoker with an apparent pulmonary mass on chest radiograph, the differential diagnosis rapidly narrows to a short list of possibilities that include pulmonary neoplasm, pulmonary infection and pulmonary infarction. Pulmonary hypertension with pulmonary arterial enlargement and hypoxia secondary to alveolar hypoventilation should also, however, be included as a diagnostic possibility in the appropriate setting because the evaluation and treatment of this entity may differ markedly. 相似文献
995.
The authors describe a robust channel prediction technique for a direct sequence spread spectrum (DS-SS) system in a fast fading environment. Coherent diversity reception is employed for improved performance. To estimate the channel response, an FIR type linear prediction filter is employed for each RAKE tap. The stability of the decision directed receiver is achieved through differential encoding of the data bits. It is demonstrated through simulations that the performance of the proposed decision directed receiver is better than a receiver which relies on a pilot signal 相似文献
996.
The authors discuss maximum likelihood sequence detection (MLSD) based on prediction techniques for linearly modulated digital signals transmitted over fading channels. Efficient implementations of the sequence detector are investigated and a general formulation for computing the prediction coefficients is derived. Furthermore, the equivalence of different existing prediction-based receivers is shown 相似文献
997.
998.
SC Bowden B Dodds G Whelan C Long P Dudgeon A Ritter C Clifford 《Canadian Metallurgical Quarterly》1997,19(5):755-762
Previous analyses of the Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1987) have reported one-, two-, and three-factor solutions and raised questions about the validity of the visual memory subtests. These various findings may stem in part from different methods of analysis, and from the study of different participant samples. To address these issues, we analysed data from the WMS-R and a spatial maze test administered to 154 participants with a history of alcohol dependence. Results from confirmatory factor analysis supported the interpretation of three factors underlying the WMS-R subtests and the spatial maze score in this sample, namely, attention-concentration, immediate memory, and delayed recall. This result held despite the inclusion of the maze score which is a well-validated measure of visuo-spatial memory. 相似文献
999.
G. P. Kurbskii G. P. Kayukova G. M. Usacheva R. I. Mutalapova E. V. Lifanova T. N. Yusupva G. V. Romanov 《Chemistry and Technology of Fuels and Oils》1992,28(6):309-313
Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 7–9, June, 1992. 相似文献
1000.