首页 | 本学科首页   官方微博 | 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   1201篇
  免费   2篇
  国内免费   1篇
化学工业   3篇
矿业工程   2篇
轻工业   2篇
一般工业技术   2篇
冶金工业   1195篇
  2016年   1篇
  2015年   1篇
  2010年   1篇
  2005年   1篇
  2003年   2篇
  1999年   28篇
  1998年   320篇
  1997年   219篇
  1996年   154篇
  1995年   104篇
  1994年   60篇
  1993年   73篇
  1992年   6篇
  1991年   22篇
  1990年   7篇
  1989年   8篇
  1988年   5篇
  1987年   4篇
  1986年   3篇
  1985年   5篇
  1983年   3篇
  1982年   4篇
  1981年   11篇
  1980年   14篇
  1979年   1篇
  1978年   6篇
  1977年   47篇
  1976年   94篇
排序方式: 共有1204条查询结果,搜索用时 593 毫秒
21.
Ensuring the competency of staff members at all levels of practice is an ongoing challenge for perioperative clinical educators. The authors developed a competency-based orientation program using AORN's perioperative nursing competency statements as a conceptual framework. The model also incorporates requirements from external regulatory agencies (e.g., the Joints Commission on Accreditation of Healthcare Organizations) that influence the direction of health care institutions seeking accreditation. The model provides the components necessary to validate the orientation of perioperative staff members and the delivery of comprehensive nursing care in perioperative settings.  相似文献   
22.
The precise measurement of low numbers of leukocyte below 0.1 WBC/microliter in filtered red cell or platelet suspensions meet both aims: to check the compliance with previously determined requirements and to evaluate the performances of novel filtering material (5 log depletion or more), justified by more and more important clinical use. The reliability of results, obtained with the chosen method, is ensured by applying of validation protocol, including training of technologist, assessment of the analytical range and the detection limit, assessment of precision and accuracy. The flow cytometry (FC) and Nageotte Chamber (NC) method are the both techniques which are currently used in routine Quality Control (QC) and validated by multicenter studies. Recent developments are made for increasing the sensibility of these counting methods, thanks to higher concentration or volume of the sample to be analysed. Among the experimental techniques, requiring more advances before implementing in QC program, quantitative PCR must become essential as reference method for evaluating the efficiency of filtration, in the future.  相似文献   
23.
24.
25.
Human peripheral blood monocytes were examined for migration across an endothelial cell monolayer in an in vitro vessel wall construct. Few monocytes invaded in the absence of a chemotactic gradient, despite significant adhesion to the endothelial monolayer. However, the addition of zymosan-activated human plasma to the lower compartment, to create a chemotactic gradient across the vessel wall, resulted in significantly enhanced monocyte migration. Pretreatment of the monocytes with monoclonal antibodies to thrombospondin (TSP) dramatically inhibited monocyte diapedesis into the vessel wall. The same treatment inhibited monocyte adhesion to endothelial cells in two-dimensional monolayer cultures as well as in vessel wall constructs (no chemotactic gradient). Of interest, however, the monoclonal antibodies had no inhibitory effect on monocyte migration into collagen gels devoid of endothelial cells in response to the same chemotactic gradient, suggesting the importance of TSP in monocyte-endothelial cell interactions. Monoclonal antibodies to fibronectin and normal mouse immunoglobulin G did not inhibit migration in this model of a vessel wall. Furthermore, monoclonal antibodies to TSP showed no inhibition of human peripheral blood neutrophil migration. Previous studies have shown that monocytes synthesize TSP and express this moiety on their surface. The present data suggest that monocytes may utilize TSP to interact with endothelial cells lining the vessel wall during diapedesis.  相似文献   
26.
27.
28.
29.
OBJECTIVE: The purpose of our study was to evaluate the effectiveness of MR imaging for showing the intrinsic anatomy of a peripheral nerve. Cadaver wrist specimens that included the median nerve were imaged with MR imaging at 3 T, then sectioned, stained, and inspected grossly and microscopically. The size, shape, and signal intensity of the sheath and axonal structures in the median nerve were identified in MR images by comparison with anatomic sections. CONCLUSION: This study suggests that MR imaging with sufficiently high-resolution techniques shows the internal structure of peripheral nerves. These results suggest that MR imaging may be a means to distinguish neuritis, tumor, degeneration, or fatty proliferation in a peripheral nerve and to evaluate the nerve before microsurgical anastomosis.  相似文献   
30.
Tissue remodelling is an important feature during embryogenesis. Although the matrix metalloproteinases are believed to participate in these processes, the relation between matrix metalloproteinases and tissue remodelling during craniofacial morphogenesis remains unclear. The purpose of the study was to look for the presence of enzymes involved in extracellular matrix degradation during craniofacial morphogenesis. Protein expression of the matrix metalloproteinase, 72-kDa gelatinase (matrix metalloproteinase-2, gelatinase A, 72-kDa type IV collagenase) was studied by gelatine zymography and by indirect immunofluorescence with conventional and confocal microscopy. In the anterior region of the developing mouse face, 72-kDa gelatinase was labelled mainly in the tips and peripheral regions of the nasal and facial prominences. Upon contact and fusion of the prominences, the staining was intensely localized to the zone of the fusion and the tips and peripheral regions of the nasal prominences and the maxilla. The labelling of 72-kDa gelatinase was also present in the peripheral regions of the mandible, second branchial arch, and the face around the developing eye. However, during lens vesicle formation, the staining of 72-kDa gelatinase was absent in the invaginated lens ectoderm. After the lens had completely detached from the surface ectoderm, the staining was resumed in the corneal epithelium and mesenchyme. Gelatine zymography was used to confirm the presence of active and latent 72-kDa gelatinase in the developing mouse craniofacial complex. Collectively, these data indicate that 72-kDa gelatinase may play a significant part in localized tissue remodelling during craniofacial morphogenesis and the aberrant expression or function of the enzyme could be involved in causing facial abnormalities.  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