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   192篇
  免费   5篇
  国内免费   5篇
教育   111篇
科学研究   67篇
体育   3篇
综合类   1篇
信息传播   20篇
  2022年   2篇
  2021年   7篇
  2020年   2篇
  2019年   4篇
  2018年   6篇
  2017年   2篇
  2016年   6篇
  2015年   1篇
  2014年   5篇
  2013年   14篇
  2012年   29篇
  2011年   16篇
  2010年   14篇
  2009年   13篇
  2008年   8篇
  2007年   17篇
  2006年   14篇
  2005年   12篇
  2004年   10篇
  2003年   3篇
  2002年   1篇
  2001年   3篇
  2000年   3篇
  1997年   7篇
  1993年   1篇
  1991年   2篇
排序方式: 共有202条查询结果,搜索用时 20 毫秒
1.
浙江省已于2014年启动科技报告制度建设工作,并将在“十三五”期间建成全省统一的科技报告管理体 系,对浙江省科技报告制度建设进行研究探讨有着重要意义。文章简述浙江省科技报告制度建设的基本思路,介绍开 展制度建设一年来浙江省工作特色与成效,并建议从以下4方面入手深入推进浙江省科技报告工作:进一步实现与科研 项目管理的无缝衔接,推行科技报告规范化管理,建立和完善科技报告质量评价机制,进一步完善科技报告开放和共 享机制。  相似文献   
2.
Objective: We aim to describe the environment iodine concentration in salt, water and soil along Zhejiang Province coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers) and soil samples through random sampling in June, 2005. Salt, water and soil iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as mean±SEMby Windows SPSS 13.0. Results: (1) The iodine concentration in salt was 27.9±4.33 mg/kg (n=108). (2) Seventy-five water samples were collected. The water iodine value was 0.6~84.8 μg/L (mean of 11.66 μg/L). The watershed along the Qiantang River has significantly higher iodine content than the water in Lin'an in mountain area (P<0.01). The iodine content and mean iodine content of tap water, well or spring water and natural water sources were 4.30±2.43 μg/L (n=34), 23.59±27.74 μg/L (n=19)and 12.72±10.72 μg/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P<0.01). (3) Soil iodine value was 0.11~2.93 mg/kg (mean of 1.32 mg/kg).Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. Conclusion: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution.  相似文献   
3.
分析了浙江省区域产业集群中企业信息需求的变化及特征,探讨了当前科技信息服务的现状和存在问题.在借鉴新的服务手段、服务方式、服务经验的基础上,结合浙江省区域产业集群的科技信息服务实践,探求科技信息服务新策略,提出基于区域产业特色的科技信息服务发展的思路.  相似文献   
4.
【目的】为我国科技期刊加快提升国际影响力提供带有样本意义的策略与参考举措。【方法】从核心定位、严苛要求、关键优势三个方面总结提炼了“高精尖”策略的定义,分析了该策略是建设国际一流科技期刊首选的办刊思路。【结果】提出了加速推进国际化“高聚合”、全流程“高精准”、持续性“高被引”,实施“高精尖”策略的具体举措。【结论】未来我国科技期刊会以梯队、集群的阵列,牢牢占据各大研究领域的“制高点”,不断实现国际影响力的重大突破。  相似文献   
5.
赵虹 《科技通报》1997,13(2):130-132
采用吲哚美辛栓剂肛塞用于人工流产前孕妇200例,观察到可以明显减少流产时各种症状的发生,减轻术中疼痛.与未用药组100例进行对比分析,P<0.01.不良反应少.并对使用该药的优点进行初步探讨  相似文献   
6.
葛慧丽 《现代情报》2011,31(6):46-49
在国家科技基础条件平台建设发展同时,各地区、各部门都采取了相应的政策、措施推动科技资源共享,科技资源的共享已经有了较快的进展,科技文献平台作为科技基础条件平台之一也得到了迅速发展。文章在调查分析了各区域科技文献平台发展现状,在分析发展障碍的基础上提出了使科技文献平台更有效地服务于区域科技创新的思考。  相似文献   
7.
吕琼芳 《现代情报》2011,31(9):129-131
在科技发展日新月异,市场竞争日趋激烈的现代社会,信息已成为企业竞争的重要资源。加强面向企业技术创新的竞争情报服务是现代企业的强烈要求,也是信息工作者的时代重任。本文浅论了竞争情报的内涵和作用及其在技术创新中的作用、竞争情报的获取途径和方法,并通过企业竞争情报服务实践工作总结探索了面向技术创新的竞争情报服务工作方法。  相似文献   
8.
Objective

The International Federation of Gynecology and Obstetrics (FIGO) 2000 scoring system classifies gestational trophoblastic neoplasia (GTN) patients into low- and high-risk groups, so that single- or multi-agent chemotherapy can be administered accordingly. However, a number of FIGO-defined low-risk patients still exhibit resistance to single-agent regimens, and the risk factors currently adopted in the FIGO scoring system possess inequable values for predicting single-agent chemoresistance. The purpose of this study is therefore to evaluate the efficacy of risk factors in predicting single-agent chemoresistance and explore the feasibility of simplifying the FIGO 2000 scoring system for GTN.

Methods

The clinical data of 578 GTN patients who received chemotherapy between January 2000 and December 2018 were retrospectively reviewed. Univariate and multivariate logistic regression analyses were carried out to identify risk factors associated with single-agent chemoresistance in low-risk GTN patients. Then, simplified models were built and compared with the original FIGO 2000 scoring system.

Results

Among the eight FIGO risk factors, the univariate and multivariate analyses identified that pretreatment serum human chorionic gonadotropin (hCG) level and interval from antecedent pregnancy were consistently independent predictors for both first-line and subsequent single-agent chemoresistance. The simplified model with two independent factors showed a better performance in predicting single-agent chemoresistance than the model with the other four non-independent factors. However, the addition of other co-factors did improve the efficiency. Overall, simplified models can achieve favorable performance, but the original FIGO 2000 prognostic system still features the highest discrimination.

Conclusions

Pretreatment serum hCG level and interval from antecedent pregnancy were independent predictors for both first-line and subsequent single-agent chemoresistance, and they had greater weight than other non-independent factors in predicting single-agent chemoresistance. The simplified model composed of certain selected factors is a promising alternative to the original FIGO 2000 prognostic system, and it shows comparable performance.

  相似文献   
9.

Objective

To investigate stretch-induced electrophysiological changes in chronically infarcted hearts and the effect of streptomycin (SM) on these changes in vivo.

Methods

Sixty Wistar rats were divided randomly into four groups: a control group (n=15), an SM group (n=15), a myocardial infarction (MI) group (n=15), and an MI+SM group (n=15). Chronic MI was obtained by ligating the left anterior descending branch (LAD) of rat hearts for eight weeks. The in vivo blockade of stretch-activated ion channels (SACs) was achieved by intramuscular injection of SM (180 mg/(kg·d)) for seven days after operation. The hearts were stretched for 5 s by occlusion of the aortic arch. Suction electrodes were placed on the anterior wall of left ventricle to record the monophasic action potential (MAP). The effect of stretching was examined by assessing the 90% monophasic action potential duration (MAPD90), premature ventricular beats (PVBs), and ventricular tachycardia (VT).

Results

The MAPD90 decreased during stretching in both the control (from (50.27±5.61) ms to (46.27±4.51) ms, P<0.05) and MI groups (from (65.47±6.38) ms to (57.47±5.76 ms), P<0.01). SM inhibited the decrease in MAPD90 during inflation ((46.27±4.51) ms vs. (49.53±3.52) ms, P<0.05 in normal hearts; (57.47±5.76) ms vs. (61.87±5.33) ms, P<0.05 in MI hearts). The occurrence of PVBs and VT in the MI group increased compared with that in the control group (PVB: 7.93±1.66 vs. 1.80±0.86, P<0.01; VT: 7 vs. 1, P<0.05). SM decreased the occurrence of PVBs in both normal and MI hearts (0.93±0.59 vs. 1.80±0.86 in normal hearts, P<0.05; 5.40±1.18 vs. 7.93±1.66 in MI hearts, P<0.01).

Conclusions

Stretch-induced MAPD90 changes and arrhythmias were observed in chronically infarcted myocardium. The use of SM in vivo decreased the incidence of PVBs but not of VT. This suggests that SACs may be involved in mechanoelectric feedback (MEF), but that there might be other mechanisms involved in causing VT in chronic MI.  相似文献   
10.
提出一种基于树状小波的图像融合,其基本思想是首先对源图像进行树状小波分解,之后采用基于像素、区域的选择或边缘检测的融合算法来构造融合图像的小波系数,最后通过树状小波逆变换重构得到融合图像.此外,利用熵、图像均值、均方根误差、峰值信噪比等参量对该融合方法的融合性能进行评价与分析.实验结果表明该融合方法是有效的.  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