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   3599篇
  免费   238篇
  国内免费   32篇
财政金融   50篇
工业经济   144篇
计划管理   684篇
经济学   229篇
综合类   137篇
运输经济   2篇
旅游经济   2篇
贸易经济   143篇
农业经济   133篇
经济概况   230篇
水利工程   2115篇
  2024年   5篇
  2023年   33篇
  2022年   66篇
  2021年   81篇
  2020年   56篇
  2019年   55篇
  2018年   57篇
  2017年   68篇
  2016年   86篇
  2015年   168篇
  2014年   277篇
  2013年   238篇
  2012年   293篇
  2011年   414篇
  2010年   310篇
  2009年   252篇
  2008年   214篇
  2007年   231篇
  2006年   218篇
  2005年   191篇
  2004年   158篇
  2003年   89篇
  2002年   59篇
  2001年   54篇
  2000年   54篇
  1999年   38篇
  1998年   29篇
  1997年   18篇
  1996年   13篇
  1995年   17篇
  1994年   9篇
  1993年   4篇
  1992年   2篇
  1991年   5篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1983年   2篇
  1981年   1篇
排序方式: 共有3869条查询结果,搜索用时 421 毫秒
1.
Aims: The EINSTEIN-Extension trial (EINSTEIN-EXT) found that continued treatment with rivaroxaban for an additional 6 or 12 months (vs placebo) after 6–12 months of initial anticoagulation significantly reduced the risk of recurrent venous thromboembolism (VTE) with a small non-significant increased risk of major bleeding (none fatal or in critical site). This study aimed to compare total healthcare cost between rivaroxaban and placebo, based on the EINSTEIN-EXT event rates.

Methods: Total healthcare cost was calculated as the sum of treatment and clinical event costs from a US managed care perspective. Treatment duration and event rates were obtained from the EINSTEIN-EXT study. Adjustment on treatment duration was made by assuming a 10% non-adherence rate. Drug costs were based on wholesale acquisition costs. Cost estimates for clinical events (i.e. recurrent deep vein thrombosis [DVT], recurrent pulmonary embolism, major bleeding, clinically relevant non-major bleeding) were determined from the literature. Results were examined over a ±20% range of each cost component and over 95% confidence intervals (CIs) of event rate differences in deterministic (one-way) and probabilistic sensitivity analyses (PSA).

Results: Total healthcare cost was $1,454 lower for rivaroxaban-treated (vs placebo-treated) patients in the base-case, with a lower clinical event cost fully offsetting drug cost. The cost savings of recurrent DVT alone (–$3,102) was greater than drug cost ($2,723). Total healthcare cost remained lower for rivaroxaban in the majority (73%) of PSA (cost difference [95% CI]?=?–$1,454 [–$2,396, $1,231]).

Limitations: This study was conducted over the 1-year observation period of the EINSTEIN-EXT trial, which limited “real-world” applicability and examination of long-term economic impact. Assumptions on drug and clinical event costs were US-based and, thus, not applicable to other healthcare systems.

Conclusions: Total healthcare costs were estimated to be lower for patients continuing rivaroxaban therapy compared to those receiving placebo in VTE patients who had completed 6–12 months of VTE treatment.  相似文献   
2.
Aims: The Anti-Clot Treatment Scale (ACTS) and Treatment Satisfaction Questionnaire for Medication version II (TSQM-II) are validated treatment satisfaction patient-reported outcome (PRO) instruments. The ACTS includes two domains: Burdens and Benefits; the TSQM-II includes four: Effectiveness, Side Effects, Convenience, and Global Satisfaction. Japanese-language versions of the ACTS and TSQM-II have been developed and linguistically validated. This study aimed to assess their psychometric properties in Japanese patients with atrial fibrillation (AF).

Materials and methods: ACTS and TSQM-II data from 534 patients with AF were collected in a Japanese post-marketing surveillance study of a direct oral-anticoagulant, rivaroxaban. Four key psychometric properties, in line with best practice guidelines from the US Food and Drug Administration, were examined using traditional psychometric methods: acceptability, scaling assumptions, reliability (i.e. internal consistency reliability, test-retest reliability), and construct validity (i.e. convergent validity and known groups).

Results: ACTS Burdens and Benefits and TSQM-II Effectiveness, Convenience, and Global Satisfaction scales were found to be acceptable (e.g. item-level missing data at baseline <4%), with all scales having good internal consistency (Cronbach’s alpha > 0.80). test-retest reproducibility intraclass correlation coefficients for the ACTS Burdens and Benefits were 0.59 and 0.65, respectively, and between 0.54–0.61 for the TSQM-II scales. Known-groups validity for the ACTS and TSQM-II was supported by differences in scale scores by positive and negative impact (p?<?0.05). Correlations between the ACTS and TSQM-II (convergent validity) were lower than expected (range r?=?0.09–0.48), but in line with the original ACTS development study.

Limitations: Evaluation of test-retest reproducibility was limited by assessment period, which was longer (3 months) than recommended guidelines (usually up to 2 weeks).

Conclusions: Overall, Japanese versions of ACTS and TSQM-II scales satisfied internal consistency reliability and traditional validity criteria. Our study supports the ACTS and TSQM-II as appropriate PRO instruments to measure satisfaction with anticoagulant treatment in Japanese patients with AF.

Trial registration: NCT01598051, clinicaltrials.gov; registered April 20, 2012.  相似文献   
3.
采油污水处理工艺探讨   总被引:3,自引:0,他引:3  
针对采油污水的水质特点,以及其中有机污染物的组成,结合现有处理工艺,确定了以生化法降解有机污染物为核心的处理工艺,实现了达标排放,并对处理工艺适用性进行了分析。  相似文献   
4.
根据洗浴废水的水质特征,采用原水→混凝沉淀-过滤→固定化生物活性炭(Immobilized Biological Activated Carbon,IBAC)→微滤膜(MF)→UV消毒→出水的工艺流程.混凝沉淀-过滤物化预处理单元可以有效地减少洗浴废水中的各类污染物.IBAC生化处理单元,实现有机污染物、LAS、浴臭等有效去除,是保证出水合格的根本措施.微滤膜发挥物理截留作用、UV消毒杀死细菌和总大肠菌群.出水水质达到<城市供水水质标准>(CJ/T 206-2005).  相似文献   
5.
硫化物预处理方法研究及测定中的质量保证   总被引:1,自引:0,他引:1  
黄敏 《水资源保护》2006,22(1):78-80
针对水和废水中硫离子的特点,设计制作了测定硫化物的酸化—吹气—吸收预处理装置,并验证了该装置对硫化物的回收效果,简化了原来的预处理方法。总结分光测定过程中注意的若干事项,确定了最佳实验条件,使该方法具有更准确、简便、快速的特点。  相似文献   
6.
An approach is presented to satisfy the demand for simple criteria, guidelines and models for the preliminary sizing of horizontal subsurface flow (SF) constructed wetland systems. This approach eliminates time-consuming calculations and iterations by providing graphical solutions for wetland system sizing. Therefore, it can be used for the preliminary assessment of new or performance evaluation of existing subsurface flow constructed wetland systems. The validity of this methodology is checked with data from existing systems and is found to be quite satisfactory. This methodology is combined with simple equations predicting the maximum wetland capacity in summer, so as to assist designers in sizing installations in tourist areas with increased summer populations. Furthermore, based on this methodology, a sensitivity analysis is performed of the area requirements for wastewaters of various strengths and various design conditions and performance criteria. The results provide a useful overview to engineers and further simplify the design methodology of new subsurface flow constructed wetland systems.  相似文献   
7.
温州市龙湾段标准堤地基土中普遍存在一层海积淤泥,其强度低,压缩性高,承载力低,不能满足标准堤填筑及水闸运行的要求。采用预压法进行地基处理,取得的地基沉降、水平位移、孔隙水压力等现场观测资料,总结分析了该段海积淤泥地基的变形规律和特点。并提供了有关的原型观测数据,其沉降曲线规律性较好。  相似文献   
8.
徐建军  叶建群 《水力发电》2006,32(10):50-52
牛头山水电站大坝为抛物线形混凝土双曲拱坝,最大坝高108.0 m,采用坝顶5孔开敞式溢洪道泄洪,挑流消能。为提前发挥水电站效益,在拱坝尚未完全封拱的情况下,通过计算分析,得出了水库可以下闸蓄水的结论。  相似文献   
9.
小浪底水库投入运用后,黄河下游水沙条件的变化,使游荡性河道整治出现了新情况,新问题。下一步治理应注意积极修建新布点工程,完成具有关键性导流作用的续建工程,确定适应新情况的设计治导线,积极开展新结构试验和观测研究。  相似文献   
10.
关于长江重大问题的思考   总被引:2,自引:0,他引:2  
长江流域横跨我国华东、华中、西南三大经济区,地理位置优越,水资源得天独厚,是我国最重要的经济区域之一。新中国成立后,党和政府高度重视长江治理开发工作,组建了流域机构,开展了流域综合利用规划,初步建立了长江防洪、灌溉、水力发电、航运、水土保持和水资源保护体系,在保护  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