首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6116篇
  免费   11篇
  国内免费   1篇
工业技术   6128篇
  2023年   6篇
  2022年   8篇
  2021年   12篇
  2020年   17篇
  2019年   13篇
  2018年   24篇
  2017年   17篇
  2016年   15篇
  2014年   9篇
  2013年   24篇
  2012年   11篇
  2011年   8篇
  2010年   11篇
  2009年   5篇
  2008年   6篇
  2007年   8篇
  2006年   10篇
  2005年   12篇
  2004年   9篇
  2003年   15篇
  2002年   4篇
  2001年   3篇
  2000年   3篇
  1999年   187篇
  1998年   1923篇
  1997年   1103篇
  1996年   705篇
  1995年   381篇
  1994年   276篇
  1993年   359篇
  1992年   46篇
  1991年   44篇
  1990年   55篇
  1989年   44篇
  1988年   38篇
  1987年   40篇
  1986年   35篇
  1985年   45篇
  1984年   3篇
  1983年   9篇
  1982年   23篇
  1981年   38篇
  1980年   56篇
  1979年   3篇
  1978年   15篇
  1977年   129篇
  1976年   291篇
  1975年   15篇
  1973年   3篇
  1955年   4篇
排序方式: 共有6128条查询结果,搜索用时 15 毫秒
21.
22.
Prognostic significance of cathepsin-D in patients with breast cancer   总被引:1,自引:0,他引:1  
The expression of the protease cathepsin-D has been evaluated using an immunohistochemical technique with a polyclonal antibody in paraffin-embedded tissue from 359 patients treated between the years 1975-1981 for Stage I and II breast cancer. One hundred and twenty seven patients (35%) have strongly positive, granular staining, 138 (38%) are intermediately stained in the cytoplasm, and in 94 (26%) no staining is observed. There is a strong positive association between expression of cathepsin-D and the presence of tumour in axillary lymph nodes (P < 0.006). Expression of the protease is associated with significantly poorer survival of patients in univariate analysis (P = 0.025); however, this is not independent of other tumour variables.  相似文献   
23.
Urinary incontinence is most frequently associated with the elderly, particularly women, and is often thought of as inevitable. However, orthopaedic nurses encounter incontinence as a response to alterations in orthopaedic health. This article reviews the types of urinary incontinence, with emphasis on those which may most directly result from orthopaedic problems. It will also help the nurse differentiate between types of incontinence in a way that will clarify appropriate interventions.  相似文献   
24.
25.
The rostral migratory stream consists of a large number of cells migrating from the lateral ventricles to the rostral telencephalon, primarily the olfactory bulb. The pathway continually provides neuro- and glioblasts throughout life. The present paper indicates that a considerable number of cells undergo apoptotic cell death en route, even in young (day 3) rats when presumably many vacant sites are still available in the developing brain.  相似文献   
26.
Flexible manufacturing systems (FMSs) are a class of automated systems that can be used to improve productivity in batch manufacturing. Four stages of decision making have been defined for an FMS—the design, planning, scheduling, and control stages. This research focuses on the planning stage, and specifically in the area of scheduling batches of parts through the system.The literature to date on the FMS planning stage has mostly focused on the machine grouping, tool loading, and parttype selection problems. Our research carries the literature a step further by addressing the problem of scheduling batches of parts. Due to the use of serial-access material-handling systems in many FMSs, the batch-scheduling problem is modeled for a flexible flow system (FFS). This model explicitly accounts for setup times between batches that are dependent on their processing sequence.A heuristic procedure is developed for this batch-scheduling problem—the Maximum Savings (MS) heuristic. The MS heuristic is based upon the savings in time associated with a particular sequence and selecting the one with the maximum savings. It uses a two-phase method, with the savings being calculated in phase I, while a branch-and-bound procedure is employed to seek the best heuristic solution in phase II. Extensive computational results are provided for a wide variety of problems. The results show that the MS heuristic provides good-quality solutions.  相似文献   
27.
28.
Cell cycle. The NIMA kinase joins forces with Cdc2   总被引:1,自引:0,他引:1  
The NIMA and Cdc2 protein kinases cooperate to regulate mitosis in Aspergillus nidulans. NIMA-related pathways have now begun to emerge in higher eukaryotes.  相似文献   
29.
30.
Twenty seven Aeromonas strains (5A. hydrophila, 8A. sobria and 14A. caviae) isolated from children with diarrhoea and 34 Aeromonas strains (9A. hydrophila, 7A. sobria an 18A. caviae) isolated from children without diarrhoea were tested from haemolysin production. The results obtained showed that haemolysin production using human, horse or sheep erythrocytes was significantly associated with A.hydrophila and A sobria but not with A.caviae, regardless of whether these strains were isolated from children with or without diarrhoea. Human or horse rather than sheep erythrocytes are recommended for use in the haemolysin assay.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号