全文获取类型
收费全文 | 771篇 |
免费 | 0篇 |
专业分类
化学工业 | 8篇 |
金属工艺 | 13篇 |
机械仪表 | 4篇 |
建筑科学 | 8篇 |
能源动力 | 3篇 |
轻工业 | 32篇 |
石油天然气 | 1篇 |
一般工业技术 | 19篇 |
冶金工业 | 677篇 |
原子能技术 | 1篇 |
自动化技术 | 5篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 7篇 |
2013年 | 11篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 5篇 |
2005年 | 1篇 |
2004年 | 6篇 |
2001年 | 1篇 |
1999年 | 18篇 |
1998年 | 192篇 |
1997年 | 119篇 |
1996年 | 74篇 |
1995年 | 41篇 |
1994年 | 34篇 |
1993年 | 39篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 21篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 28篇 |
1976年 | 41篇 |
1975年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有771条查询结果,搜索用时 15 毫秒
681.
682.
683.
684.
This article presents guidelines for developing workshops based on practical experience and a review of the literature. Health science faculty tend to prefer workshops as a method of learning. However, the success of a workshop depends on thoughtful planning. The needs and expectations of participants should be thoroughly assessed. Workshop leaders must be competent, enthusiastic, and flexible; they must create a successful adult learning environment, especially for professionals with teaching experience. Evaluation of workshops should include both formative and summative methods. 相似文献
685.
A model that explains the relationship between a project and its social environments is described. Tools used in the analysis of the environment are discussed, and an example of their practical application is presented. 相似文献
686.
687.
The ability of human infants < or = 4 months of age to pursue objects smoothly with their eyes was assessed by presenting small target spots moving with hold-ramp-hold trajectories at ramp velocities of 4-32 deg/sec. Infants as young as 1 month old followed such target motions with a combination of smooth-pursuit and saccadic eye movements interrupted occasionally by periods when the eyes remained stationary. The slowest targets produced variable performance, but targets moving 8-32 deg/sec produced consistent pursuit behavior, even in the youngest infants. By the fourth month, eye-movement latency decreased and smooth-pursuit gain and the percentage of smooth pursuit per trial increased for all target velocities, though these measures had not yet reached adult levels. 相似文献
688.
The use of sodium acetate acetic acid formalin (SAF)-preserved stool specimens was compared with that of nonpreserved specimens for the recovery of intestinal protozoa. A total of 247 patients, 170 with diarrhea of more than one week's duration and 77 refugees, were asked to collect a stool specimen. Each specimen was placed into two vials, one empty, the other containing SAF fixative. Laboratory investigations included microscopic examination of the concentrated sediment and direct wet smears from both types of stool specimens and the microscopic examination of a permanent stained smear from the unsedimented, SAF-preserved stool specimens. Examination of SAF-preserved stool specimens revealed intestinal protozoa in 149 of the 247 patients. With the conventional procedure using unpreserved stool specimens, intestinal protozoa were found in 89 of the 247 patients. The results show that the examination of SAF-preserved stool specimens, consisting of the microscopic examination of both the concentrated sediment and the permanent stained smear from the unsedimented material, increases the chance of recovering intestinal protozoa as compared to the conventional procedure. 相似文献
689.
Having strong current on the west coast with up to 10 m tidal range in Korea,there are many suitable and applicable locations for TCP(Tidal Current Power) application in Korea.Not only the west coast,but also the south west regions having narrow channels between islands creating fast ocean stream are suitable for TCP.The first TCP application in Korea is 1 MW helical VAT(Vertical Axis Turbine) device installed in Wooldolmog area in 2008.The first HAT(Horizontal Axis Turbine) TCP device of 25 KW was develope... 相似文献
690.
Molecular analysis of complex modular structures, such as promoter regions or multi-domain proteins, often requires the creation of families of experimental DNA constructs having altered composition, order, or spacing of individual modules. Generally, creation of every individual construct of such a family uses a specific combination of restriction sites. However, convenient sites are not always available and the alternatives, such as chemical resynthesis of the experimental constructs or engineering of different restriction sites onto the ends of DNA fragments, are costly and time consuming. A general cloning strategy (nucleic acid ordered assembly with directionality, NOMAD; WWW resource locator http:@Lmb1.bios.uic.edu/NOMAD/NOMAD.htm l) is proposed that overcomes these limitations. Use of NOMAD ensures that the production of experimental constructs is no longer the rate-limiting step in applications that require combinatorial rearrangement of DNA fragments. NOMAD manipulates DNA fragments in the form of "modules" having a standardized cohesive end structure. Specially designed "assembly vectors" allow for sequential and directional insertion of any number of modules in an arbitrary predetermined order, using the ability of type IIS restriction enzymes to cut DNA outside of their recognition sequences. Studies of regulatory regions in DNA, such as promoters, replication origins, and RNA processing signals, construction of chimeric proteins, and creation of new cloning vehicles, are among the applications that will benefit from using NOMAD. 相似文献