全文获取类型
收费全文 | 1729篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 106篇 |
金属工艺 | 10篇 |
机械仪表 | 12篇 |
建筑科学 | 18篇 |
矿业工程 | 7篇 |
能源动力 | 9篇 |
轻工业 | 37篇 |
水利工程 | 1篇 |
无线电 | 64篇 |
一般工业技术 | 88篇 |
冶金工业 | 1331篇 |
原子能技术 | 11篇 |
自动化技术 | 44篇 |
出版年
2019年 | 5篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 27篇 |
2012年 | 10篇 |
2011年 | 21篇 |
2010年 | 11篇 |
2009年 | 16篇 |
2008年 | 15篇 |
2007年 | 14篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 11篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 12篇 |
2000年 | 10篇 |
1999年 | 43篇 |
1998年 | 394篇 |
1997年 | 246篇 |
1996年 | 154篇 |
1995年 | 67篇 |
1994年 | 75篇 |
1993年 | 79篇 |
1992年 | 20篇 |
1991年 | 27篇 |
1990年 | 13篇 |
1989年 | 29篇 |
1988年 | 32篇 |
1987年 | 21篇 |
1986年 | 32篇 |
1985年 | 21篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 36篇 |
1976年 | 62篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1970年 | 6篇 |
1957年 | 5篇 |
1955年 | 5篇 |
1954年 | 6篇 |
1948年 | 5篇 |
排序方式: 共有1741条查询结果,搜索用时 15 毫秒
1.
JN Myers 《Canadian Metallurgical Quarterly》1994,21(3):415-437
2.
3.
To monitor the use of synthetic growth promoting hormones in red meat animals requires a sensitive and rapid method of analysis. This paper describes the development of such a method for these agents in bile, based on a high pressure liquid chromatographic purification procedure with detection and estimation by radioimmunoassay. 相似文献
4.
JN Nasedkin 《Canadian Metallurgical Quarterly》1998,19(7):671-4, 676, 678 passim; quiz 684
The directed shrinkage approach was developed to create sealed tooth-restoration interfaces in posterior composite restorations. Creative application of this technique can result in foundations that are suitable for a variety of applications, including salvaging broken-down teeth and supporting free-hand restorations. The sealed interface reduces microleakage and postoperative tooth sensitivity. The components required for this technique are readily available and are usually part of the practice's armamentarium. 相似文献
5.
There is growing evidence that face recognition is "special" but less certainty concerning the way in which it is special. The authors review and compare previous proposals and their own more recent hypothesis, that faces are recognized "holistically" (i.e., using relatively less part decomposition than other types of objects). This hypothesis, which can account for a variety of data from experiments on face memory, was tested with 4 new experiments on face perception. A selective attention paradigm and a masking paradigm were used to compare the perception of faces with the perception of inverted faces, words, and houses. Evidence was found of relatively less part-based shape representation for faces. The literatures on machine vision and single unit recording in monkey temporal cortex are also reviewed for converging evidence on face representation. The neuropsychological literature is reviewed for-evidence on the question of whether face representation differs in degree or kind from the representation of other types of objects. 相似文献
6.
BACKGROUND: Clinical manifestations and course of sickle-cell anemia are variable. Knowledge about the factors, possibly geographic, that influence prognosis are still scanty. POPULATION AND METHODS: Data of hospitalization and management of children with sickle-cell disease were studied during two years (1992-1993) in the Pediatric Unit of Libreville Hospital. They concerned 205 admissions of 171 children and 131 outpatients. RESULTS: The main causes of hospitalization were: acute anemia (36 cases before the age of 5 years); painful crisis whose frequency increased with age (23% before 5 years, 35% between 5 and 10, 42% after 10 years); infections, essentially pulmonary occurring early, and bone infections at any age. Eight children died (because a complication of their disease). Among the 131 outpatients, half were detected because pyrexia, anemia and/or more often "hand-foot syndrome". More than 60% had hepatomegaly, one third still had splenomegaly after five years of age and more than one third was icteric. More than half children older than ten years had growth disorders. Mean hemoglobin level was 7 g/dL. 21 of the 83 tested children for HBsAg were positive and only one out of 79 was positive for HIV. CONCLUSIONS: Clinical manifestations and course of sickle-cell anemia in our patients are similar to those reported in Congolese children. Genetic and environmental factors may be responsible for differences with children from other, in particular French, cohorts. 相似文献
7.
JN Abramovitz 《Canadian Metallurgical Quarterly》1993,4(1):167-176
Disc disease is benign and not life threatening. Its long-term prognosis is uncertain, and spontaneous recoveries are common. The decision to perform surgery thus carries with it a heavy responsibility to provide safe treatment. "Good safe surgical technique" is essential, but it is much more than a well-rehearsed routine procedure. From preoperative evaluation to surgery to postoperative care, the surgeon must look ahead to problems that might arise. Where anticipated risks cannot be avoided, they should be minimized, and when adverse events occur, active recognition will lead to early and accurate management. 相似文献
8.
9.
10.