全文获取类型
收费全文 | 461342篇 |
免费 | 5387篇 |
国内免费 | 1212篇 |
专业分类
电工技术 | 8679篇 |
综合类 | 579篇 |
化学工业 | 70788篇 |
金属工艺 | 18058篇 |
机械仪表 | 14381篇 |
建筑科学 | 10728篇 |
矿业工程 | 2320篇 |
能源动力 | 10740篇 |
轻工业 | 42880篇 |
水利工程 | 4668篇 |
石油天然气 | 8158篇 |
武器工业 | 98篇 |
无线电 | 54367篇 |
一般工业技术 | 86688篇 |
冶金工业 | 86184篇 |
原子能技术 | 10184篇 |
自动化技术 | 38441篇 |
出版年
2021年 | 3761篇 |
2019年 | 3652篇 |
2018年 | 6274篇 |
2017年 | 6274篇 |
2016年 | 6654篇 |
2015年 | 4204篇 |
2014年 | 7188篇 |
2013年 | 19821篇 |
2012年 | 11561篇 |
2011年 | 15734篇 |
2010年 | 12462篇 |
2009年 | 13931篇 |
2008年 | 14854篇 |
2007年 | 14916篇 |
2006年 | 13447篇 |
2005年 | 12065篇 |
2004年 | 11633篇 |
2003年 | 11328篇 |
2002年 | 11074篇 |
2001年 | 10947篇 |
2000年 | 10564篇 |
1999年 | 10570篇 |
1998年 | 24935篇 |
1997年 | 17754篇 |
1996年 | 13930篇 |
1995年 | 10861篇 |
1994年 | 9690篇 |
1993年 | 9461篇 |
1992年 | 7509篇 |
1991年 | 6978篇 |
1990年 | 6997篇 |
1989年 | 6665篇 |
1988年 | 6420篇 |
1987年 | 5613篇 |
1986年 | 5561篇 |
1985年 | 6421篇 |
1984年 | 6086篇 |
1983年 | 5486篇 |
1982年 | 5187篇 |
1981年 | 5376篇 |
1980年 | 5082篇 |
1979年 | 4905篇 |
1978年 | 4799篇 |
1977年 | 5481篇 |
1976年 | 6877篇 |
1975年 | 4338篇 |
1974年 | 4196篇 |
1973年 | 4342篇 |
1972年 | 3550篇 |
1971年 | 3295篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
F. Cioffi E. M. Cohen Richard Badick 《Drug development and industrial pharmacy》1993,19(14):1741-1746
Carstensen and Rhodes1 have suggested that when, in stability programs, assays cannot be performed immediately after the protocol-designated storage time, then freezing them until such a time when assays can be performed would be a reasonable manner to retain the protocol schedule. They caution, however, that such a procedure may not be valid for dissolution data. The article to follow deals with real-time data showing that such a process is feasible for Nalidixic Acid tablets (and presumably for other tablets as well), and that, furthermore, the dissolution pattern would seem to be “frozen” as well. 相似文献
73.
An extended logistic model with a varying asymptotic upper bound for long-range peak demand forecasting is described. The model has been applied to a typical fast growing system, the Saudi Consolidated Electric Company. The forecasts are compared with actual demands and with those obtained from classical forecasting methods. The model gave relatively accurate peak demand forecasts compared with other classical methods. The model with a single load observation is capable of producing several peak demand forecasts corresponding to different levels of maximum temperature and various levels of social activity. The forecasts produced by the model were also stable irrespective of the length of the ex-post simulation period 相似文献
74.
E. Smith 《Journal of Materials Science》1993,28(4):880-884
The criterion for crack growth instability in an elastic-softening material that is subjected to displacement control loading conditions is examined. A theoretical analysis of the model of a solid containing two symmetrically situated deep cracks and with tensile loading of the remaining ligament, defines the criterion for crack growth instability. The criterion is expressed in terms of the material's softening characteristics and the solid's geometrical parameters. The analysis covers the complete spectrum of material behaviour from the case where the softening zone is very small to the case where instability does not occur until the softening zone traverses the ligament between the crack tips. 相似文献
75.
The trends in high density interconnection (HDI) multichip module (MCM) techniques that have the potential to reduce interconnection cost and production time are described. The implementation in laminated dielectric (MCM-L) technology of a workstation processor core illustrates current substrate technology capabilities. The design, routing, layout and thermal management of the processor core are described. Thin-film deposited dielectric (MCM-D) technology is discussed as a cost-effective method for future interconnection applications 相似文献
76.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented 相似文献
77.
A distributed problem solving system can be characterized as a group of individual cooperating agents running to solve common problems. As dynamic application domains continue to grow in scale and complexity, it becomes more difficult to control the purposeful behavior of agents, especially when unexpected events may occur. This article presents an information and knowledge exchange framework to support distributed problem solving. From the application viewpoint the article concentrates on the stock trading domain; however, many presented solutions can be extended to other dynamic domains. It addresses two important issues: how individual agents should be interconnected so that their resources are efficiently used and their goals accomplished effectively; and how information and knowledge transfer should take place among the agents to allow them to respond successfully to user requests and unexpected external situations. The article introduces an architecture, the MASST system architecture, which supports dynamic information and knowledge exchange among the cooperating agents. The architecture uses a dynamic blackboard as an interagent communication paradigm to facilitate factual data, business rule, and command exchange between cooperating MASST agents. The critical components of the MASST architecture have been implemented and tested in the stock trading domain, and have proven to be a viable solution for distributed problem solving based on cooperating agents 相似文献
78.
79.
Rapeseed protein concentrate (RC), prepared with 2% hexameta-phosphate, was tested for its functionality and performance in some foods. The RC had good nitrogen solubility, fat absorption, emulsification, and whipping capacities but poor water absorption and gelling properties. It increased the emulsion stability, and protein but lowered the fat content of wieners. It also increased the cooking yield, reduced the shrinkage and tenderized meat patties. Results were similar to soybean isolate except for the poorer color and flavor. The cooking yield of RC supplemented wieners was less than the all-meat control and soybean-supplemented wieners. A 9% RC dispersion mixed with an equal volume of eggwhite produced a meringue of comparable stability and texture to that of eggwhite alone. 相似文献
80.
M. D. Korostash 《Drying Technology》1985,3(4):603-611
The paper presents the results of research in the convection drying of unidirectional glass fibre bobbins on the basis of which the relations are suggested required to calculate the process of drying in the design of drying equipment. 相似文献