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   1169篇
  免费   84篇
  国内免费   145篇
  2024年   4篇
  2023年   26篇
  2022年   32篇
  2021年   41篇
  2020年   28篇
  2019年   39篇
  2018年   45篇
  2017年   82篇
  2016年   54篇
  2015年   78篇
  2014年   138篇
  2013年   166篇
  2012年   75篇
  2011年   93篇
  2010年   77篇
  2009年   41篇
  2008年   50篇
  2007年   42篇
  2006年   36篇
  2005年   26篇
  2004年   27篇
  2003年   24篇
  2002年   29篇
  2001年   22篇
  2000年   12篇
  1999年   16篇
  1998年   14篇
  1997年   12篇
  1996年   9篇
  1995年   12篇
  1994年   8篇
  1993年   5篇
  1992年   9篇
  1991年   2篇
  1990年   8篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   2篇
  1983年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1976年   1篇
  1974年   1篇
  1972年   1篇
排序方式: 共有1398条查询结果,搜索用时 15 毫秒
131.
Summary A technical approach, in terms of air quality, implies the review of all components within the air conditioning system and the check of their characteristics, as far as contamination sources are concerned. The contribution introduces the parameters to be examined and specifies the importance of validation.  相似文献   
132.
Natural disasters in populated areas may result in massive casualties and extensive destruction of infrastructure. Humanitarian aid delegations may have to cope with the complicated issue of patient prioritization under conditions of severe resource scarcity. A triage model, consisting of five principles, is proposed for the prioritization of patients, and it is argued that rational and reasonable agents would agree upon them. The Israel Defense Force's humanitarian mission to Haiti following the 2010 earthquake serves as a case study for the various considerations taken into account when designing the ethical‐clinical policy of field hospitals. The discussion focuses on three applications: the decision to include an intensive care unit, the decision to include obstetrics and neonatal units, and the treatment policy for compound fractures.  相似文献   
133.
Paederus jianyueae Peng & Li, sp. n. (Zhejiang: Qingliangfeng) is described and illustrated. Additional records of P. biacutus Li, Zhou & Solodovnikov, 2014 and P. parvidenticulatus Li, Zhou & Solodovnikov, 2014 are reported.  相似文献   
134.
Abstract

Melittobia australica Girault is a new record for New Zealand and from Vespula spp. In the Wellington district, M. australica was found in an embryo colony of the German wasp Vespula germanica (Fabricius) and in pupae of the mason wasp Pison spinolae Shuckard in 1980 and 1981 respectively. Melittobia was recorded in nests of P. morosum Smith in Canterbury, New Zealand in 1976 and 1977. The original sources of M. australica were considered.

The validity of the earliest record of Melittobia in a social wasp host is reconsidered. It is concluded Melittobia has been underated as a parasite of social wasps.  相似文献   
135.
正台湾灰麝鼩(Crocidura tanakae)属于鼩形目(Soricomorpha)鼩鼱科(Soricidae),首次被Kuroda于1938描述,其模式产地在中国台湾台中市(Taichung)。随后一直被认为是灰麝鼩(Crocidura attenuata)的亚种或同物异名(Corbet and Hill,1992;Hutterer,1993;Fang et al.,1997;Motoka-  相似文献   
136.
杨柳  曹新萍  尚晨  赵利清 《广西植物》2018,38(8):1096-1101
该文报道了蓼科(Polygonaceae)、龙胆科(Gentianaceae)、禾本科(Gramineae)、莎草科(Cyperaceae)、百合科(Liliaceae)、兰科(Orchidaceae)共10种植物在我国4个省区的新分布记录。其中:内蒙古分布的新记录有刺蓼[Polygonum senticosum(Meisner)FranchetSavatier]、五叶黄精(Polygonatum acuminatifolium Komarov)、丛生龙胆[Gentiana thunbergii(G.Don)Grisebach];西藏分布的新记录有冰草[Agropyron cristatum(Linnaeus)Gaertner]、沙芦草(Agropyron mongolicum Keng);陕西分布的新记录有顶冰花(Gagea chinensis Y.Z.ZhaoL.Q.Zhao)、弓喙薹草(Carex capricornis Meinshausen ex Maximowicz)、灰脉薹草[Carex appendiculata(Trautvetter)Kükenthal]和细毛火烧兰(Epipactis papillosa FranchSavatier);山西分布的新记录有和林薹草(Carex helingeeriensis L.Q.ZhaoJ.Yang)。相关的凭证标本存放于内蒙古大学植物标本馆(HIMC)中。  相似文献   
137.
提升医院的信息化程度是智慧医院建设的重要内容。构建合理有效的信息平台是提升医疗服务质量和医院管理效率的重要途径。通过对当前智慧医院建设实践的分析,阐释了三种主要医院信息平台的功能与特点,分析了医院信息平台的一般架构与模式,提供了未来智慧医院信息平台的建设路径并提出了相关的发展建议。  相似文献   
138.
139.
目的 深入分析限制医院大数据应用普及的影响因素,研究促进医院大数据应用的对策与方法。方法 采用德尔菲法自制医院大数据应用影响因素调查问卷,随机抽取中国研究型医院学会医疗分会64家会员单位会员代表进行调查,获得有效问卷104份,有效回收率为94.55%。结果 应用推广(4.14±0.65)分,管理方式(4.07±0.60)分,数据基础(3.88±0.82)分。不同性别、年龄、职称、岗位组间对于影响因素的态度差异没有统计学意义(P > 0.05)。多元线性回归分析结果显示,管理方式(b= -0.381, P=0.019)和“缺乏大数据专业化人才”(b=-0.268, P=0.011)会对医院大数据应用普及程度产生显著的负向影响关系。结论 医院大数据应用水平未能有效满足医务人员需求,应从管理顶层设计入手,重点加强大数据专业化人才的培养,同时注重提升数据基础质量和应用推广力度。  相似文献   
140.
Online access to species occurrence records has opened new windows into investigating biodiversity patterns across multiple scales. The value of these records for research depends on their spatial, temporal, and taxonomic quality. We assessed temporal patterns in records from the Australasian Virtual Herbarium, asking: (1) How temporally consistent has collecting been across Australia? (2) Which areas of Australia have the most reliable records, in terms of temporal consistency and inventory completeness? (3) Are there temporal trends in the completeness of attribute information associated with records? We undertook a multi-step filtering procedure, then estimated temporal consistency and inventory completeness for sampling units (SUs) of 50?km ×?50?km. We found temporal bias in collecting, with 80% of records collected over the period 1970–1999. South-eastern Australia, the Wet Tropics in north-east Queensland, and parts of Western Australia have received the most consistent sampling effort over time, whereas much of central Australia has had low temporal consistency. Of the SUs, 18% have relatively complete inventories with high temporal consistency in sampling. We also determined that 25% of digitized records had missing attribute information. By identifying areas with low reliability, we can limit erroneous inferences about distribution patterns and identify priority areas for future sampling.  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