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   1067128篇
  免费   63197篇
  国内免费   2337篇
耳鼻咽喉   13565篇
儿科学   35101篇
妇产科学   28983篇
基础医学   142296篇
口腔科学   26168篇
临床医学   86414篇
内科学   212533篇
皮肤病学   19618篇
神经病学   86980篇
特种医学   44914篇
外国民族医学   336篇
外科学   169689篇
综合类   21292篇
一般理论   247篇
预防医学   81765篇
眼科学   22742篇
药学   72878篇
中国医学   2422篇
肿瘤学   64719篇
  2018年   30129篇
  2017年   23839篇
  2016年   26441篇
  2015年   9574篇
  2014年   13098篇
  2013年   19880篇
  2012年   32264篇
  2011年   47345篇
  2010年   34574篇
  2009年   26781篇
  2008年   44747篇
  2007年   48453篇
  2006年   28343篇
  2005年   29443篇
  2004年   29494篇
  2003年   29592篇
  2002年   27367篇
  2001年   41599篇
  2000年   42936篇
  1999年   36408篇
  1998年   10141篇
  1997年   9335篇
  1996年   9150篇
  1995年   8532篇
  1994年   8168篇
  1993年   7637篇
  1992年   28220篇
  1991年   27054篇
  1990年   26520篇
  1989年   25410篇
  1988年   23599篇
  1987年   23203篇
  1986年   22267篇
  1985年   21176篇
  1984年   15822篇
  1983年   13496篇
  1982年   8110篇
  1979年   14591篇
  1978年   10216篇
  1977年   8629篇
  1976年   8154篇
  1975年   8964篇
  1974年   10716篇
  1973年   10183篇
  1972年   9661篇
  1971年   8917篇
  1970年   8602篇
  1969年   8042篇
  1968年   7698篇
  1967年   7086篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
61.
PM10 exposure has been found to have significant effects on a variety of physical conditions. However, whether it acts on psychopathology remains unclear. This study used 8-year data to examine the relationship between PM10 concentration and daily clinic visits of anxiety disorders. All residents of Yunlin County, Taiwan, which is a high river-dust exposure area, were selected as subjects. Data from the Taiwan National Health Insurance Research Database (NHIRD), 2002–2009, were analyzed. Individuals with any ICD code of 300.0 and 300.2 were categorized as with anxiety disorders. PM10 data were based on the Lunbei station (located at Yunlin County) of EPA, Taiwan. Time-series analysis showed that, during the observed 8 years, the number of daily clinic visits for anxiety disorders increased with PM10 levels, and the relationship remained significant after unemployment rate, and the Weighted Price Index of Taiwan Stock Exchange in the same period were controlled for. In particular, we found that there is a linear dose-response effect between daily clinic visits and PM10 levels when PM10 <?300 μg/m3; whereas a dramatically elevated daily clinic visits of anxiety disorders was found when PM10 >?300 μg/m3. Findings from this study highlight that high level of PM10 exposure derived from severe weather or environment condition may affect the occurrence of anxiety disorders. In addition, there seems to have a threshold of PM10 in elevating the risk of anxiety disorders.  相似文献   
62.

Background

The proportion of people in need of care with a migration background and therefore the demand for qualified nursing staff will increase. So far, however, considerations and concepts aiming to improve the care situation (including cultural sensitivity) for people in need of care with a migration background are lacking.

Objective

The following questions are addressed on the basis of care training for relatives with migration background and competence development for health care professionals: What content should the care training/competence development take into account? What are the limits regarding planning and implementation, and what are the suggestions for improvements?

Materials and methods

The development of care training and competence development was based on a needs and resources assessment (in the form of a systematic literature review, an expert workshop, semistructured interviews with relatives with migration background who are providing nursing care). A training manual that has been published includes research results and findings and is applicable to other target groups and settings.

Results and discussion

A transcultural training manual was developed and tested for use in outpatient care. It consists of two parts: training for relatives providing nursing care and competency training for health care specialists. It enables the planning, preparation, and implementation of training courses and includes theoretical background knowledge, practical exercises, and didactic advice. When using the manual, however, the target group should be planned at an early stage and individual needs and resources of course participants should be taken into account.
  相似文献   
63.

Background

Representative surveys collecting weight, height and MUAC are used to estimate the prevalence of acute malnutrition. The results are then used to assess the scale of malnutrition in a population and type of nutritional intervention required. There have been changes in methodology over recent decades; the objective of this study was to determine if these have resulted in higher quality surveys.

Methods

In order to examine the change in reliability of such surveys we have analysed the statistical distributions of the derived anthropometric parameters from 1843 surveys conducted by 19 agencies between 1986 and 2015.

Results

With the introduction of standardised guidelines and software by 2003 and their more general application from 2007 the mean standard deviation, kurtosis and skewness of the parameters used to assess nutritional status have each moved to now approximate the distribution of the WHO standards when the exclusion of outliers from analysis is based upon SMART flagging procedure. Where WHO flags, that only exclude data incompatible with life, are used the quality of anthropometric surveys has improved and the results now approach those seen with SMART flags and the WHO standards distribution. Agencies vary in their uptake and adherence to standard guidelines. Those agencies that fully implement the guidelines achieve the most consistently reliable results.

Conclusions

Standard methods should be universally used to produce reliable data and tests of data quality and SMART type flagging procedures should be applied and reported to ensure that the data are credible and therefore inform appropriate intervention. Use of SMART guidelines has coincided with reliable anthropometric data since 2007.
  相似文献   
64.
The purpose of this study is to document the potential impacts on indoor air quality associated with different types of building materials (wall and floor finishes) through the development of an Indoor Air Quality index. The study first identifies pollutant sources and their corresponding health impacts due to short-term and long-term exposures. The study also quantifies levels of certain pollutants within a steady-state controlled environment, comparing the results of this study with previous studies conducted in different regions. It also proposes an IAQ index as an assessment tool which can be utilized preoccupancy. The field studies were conducted in residential buildings during January and February in Cairo to monitor volatile organic compounds (VOCs), formaldehyde (HCHO), ammonia (NH3), radon gas, and particulate matter (PM). The indoor air was monitored in nine locations: four during the construction process and five following completion of construction. For this investigation, three rooms under construction within a Cairene building site were utilized to test the finishing materials. Chemical analysis and direct reading devices were used for air sampling and monitoring. The results revealed that the concentration of some pollutants decreased within the first year of construction, while others remained above target limits. The results of this study offer recommendations for engineers regarding the selection of appropriate materials through the implementation of source control strategies and an IAQ index which can be used as an assessment tool to ensure that the Indoor Air Quality meets recommended standards. Based on the conclusions and limitations of this study, recommendations for future work are documented such as the screening of materials and monitoring of Indoor Air Quality.  相似文献   
65.
Poor air quality and related health impacts are still an issue in many cities and regions worldwide. Integrated assessment models (IAMs) can support the design of measures to reduce the emissions of precursors affecting air pollution. In this study, we apply the SHERPA (screening for high emission reduction potentials for air quality) model to compare spatial and sectoral emission reductions, given country-scale emission targets. Different approaches are tested: (a) country ”uniform” emission reductions, (b) emission reductions targeting urban areas, (c) emission reductions targeting preferential sectors. As a case study, we apply the approaches to the implementation of the National Emission Ceiling Directive. Results are evaluated in terms of the reduction in average population exposure to PM2.5 overall in a country and in its main cities. Results indicate that the reduction of population exposure to PM2.5 highly depends on the way emission reductions are implemented. This work also shows the usefulness of the SHERPA model to support national authorities implementing national emission reduction targets while, at the same time, addressing their local air quality issues.  相似文献   
66.
67.
68.
69.
70.
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