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   4627篇
  免费   399篇
  国内免费   12篇
耳鼻咽喉   17篇
儿科学   150篇
妇产科学   151篇
基础医学   633篇
口腔科学   119篇
临床医学   621篇
内科学   783篇
皮肤病学   74篇
神经病学   462篇
特种医学   107篇
外科学   404篇
综合类   56篇
一般理论   4篇
预防医学   662篇
眼科学   166篇
药学   292篇
中国医学   6篇
肿瘤学   331篇
  2023年   54篇
  2022年   80篇
  2021年   167篇
  2020年   104篇
  2019年   180篇
  2018年   167篇
  2017年   113篇
  2016年   119篇
  2015年   137篇
  2014年   167篇
  2013年   230篇
  2012年   364篇
  2011年   327篇
  2010年   181篇
  2009年   178篇
  2008年   253篇
  2007年   265篇
  2006年   261篇
  2005年   258篇
  2004年   256篇
  2003年   236篇
  2002年   230篇
  2001年   47篇
  2000年   36篇
  1999年   38篇
  1998年   49篇
  1997年   44篇
  1996年   38篇
  1995年   36篇
  1994年   35篇
  1993年   31篇
  1992年   27篇
  1991年   22篇
  1990年   16篇
  1989年   20篇
  1988年   14篇
  1987年   15篇
  1986年   21篇
  1985年   12篇
  1984年   21篇
  1983年   18篇
  1982年   15篇
  1981年   17篇
  1980年   16篇
  1978年   13篇
  1977年   11篇
  1976年   11篇
  1973年   8篇
  1972年   8篇
  1970年   6篇
排序方式: 共有5038条查询结果,搜索用时 453 毫秒
71.
72.
Aims: The influence of infant positioning on the development of head orientation and plagiocephaly is not clear. This study explored the relationship between infant body and head positioning, with the development of asymmetrical head orientation and/or positional plagiocephaly. Methods: Clinician measurement of head orientation profile and parent-reported infant positioning data were collected for 94 healthy term infants at 3, 6, and 9 weeks of age. Plagiocephaly was measured at 9 weeks with the modified Cranial Vault Asymmetry Index. Results: More severe plagiocephaly was associated with longer supine-sleep-maximum (p = 0.001) and longer supine-lying-total (p = 0.014) at 6 weeks. Prone positioning was not associated with plagiocephaly. Parent-reported head asymmetry during awake and sleep time at 3 weeks identified infants with clinician-measured head asymmetry at 9 weeks. Better symmetry in head turning was associated with more side-lying-total time by 9 weeks (p = 0.013). Conclusions: Our results showed that infant positioning is associated with early head orientation and plagiocephaly development. Early parent-reported asymmetry during awake and sleep time is an important indicator for the need for professional assessment and advice. A Plagiocephaly Prevention Strategy and Plagiocephaly Screening Pathway are provided for clinicians and parents.  相似文献   
73.
74.
75.
Respiratory syndromes (RS) are among the most significant pathological conditions in edible birds and are caused by complex coactions of pathogens and environmental factors. In poultry, low pathogenic avian influenza A viruses, metapneumoviruses, infectious bronchitis virus, infectious laryngotracheitis virus, Mycoplasma spp. Escherichia coli and/or Ornithobacterium rhinotracheale in turkeys are considered as key co-infectious agents of RS. Aspergillus sp., Pasteurella multocida, Avibacterium paragallinarum or Chlamydia psittaci may also be involved in respiratory outbreaks. An innovative quantitative PCR method, based on a nanofluidic technology, has the ability to screen up to 96 samples with 96 pathogen-specific PCR primers, at the same time, in one run of real-time quantitative PCR. This platform was used for the screening of avian respiratory pathogens: 15 respiratory agents, including viruses, bacteria and fungi potentially associated with respiratory infections of poultry, were targeted. Primers were designed and validated for SYBR green real-time quantitative PCR and subsequently validated on the Biomark high throughput PCR nanofluidic platform (Fluidigm©, San Francisco, CA, USA). As a clinical assessment, tracheal swabs were sampled from turkeys showing RS and submitted to this panel assay. Beside systematic detection of E. coli, avian metapneumovirus, Mycoplasma gallisepticum and Mycoplasma synoviae were frequently detected, with distinctive co-infection patterns between French and Moroccan flocks. This proof-of-concept study illustrates the potential of such panel assays for unveiling respiratory co-infection profiles in poultry.  相似文献   
76.
77.
78.
Coral reef scientists and managers require detailed information of reef environments to develop, implement and evaluate management strategies. Maps showing the distribution of corals, seagrass, algae, sand, rubble and rock are an essential component of this information. Using a semi-automated, object-based image analysis (OBIA) approach this study created a benthic community map for Heron Reef (area: approximately 27 km2), Southern Great Barrier Reef, Australia. Benthic cover information was acquired for calibration and validation via georeferenced photograph transects, which coincided with high spatial resolution Quickbird-2 satellite image capture in 2007. Through combination of these data sets and modification of a semi-automated OBIA classification scheme previously developed for seagrass environments to account for the heterogeneous nature of reef benthic communities, a benthic community map was created for Heron Reef with an overall accuracy of 61.6%. The robustness and repeatability of our method provide future opportunity to apply the semi-automated approach to a time series of field and high spatial resolution image data sets to create a time series of benthic community maps for Heron Reef. The results presented in this study therefore open up the opportunity to assess and understand the spatial and temporal dynamics of the reef environment.  相似文献   
79.

A case study approach was used to study a 36‐year‐old Southern black female for several weeks following a hypertensive crisis episode. The purpose of the study was to establish trust and understanding between the culturally different black client and white nurse. The Betty Neuman model of nursing care was used in developing an ethnocare plan for the subject. Cultural Stressors identified were: (1) obesity and dietary habits, evidence of the “soul food”; diet and salt, saturated fats, and cholesterol; (2) smoking, used as a coping mechanism when under self‐perceived stress; (3) noncom‐pliance in taking hypertensive drugs, which reflects cultural beliefs and feelings; (4) lack of understanding about the disease process, an example of cultural difference in language and beliefs; (5) inability to be a biological mother (the ability to produce children is perceived by the black culture as necessary to the fulfillment of the woman's role); and (6) living in a hostile environment. The ethnocare plan addressed each of these Stressors and was designed to fit this client's individual perception of nursing care and its value to her.  相似文献   
80.

Purpose  

The Patient and Observer Scar Assessment Scale (POSAS) is a questionnaire that was developed to assess scar quality. It consists of two separate six-item scales (Observer Scale and Patient Scale), both of which are scored on a 10-point rating scale. After many years of experience with this scale in burn scar assessment, it is appropriate to examine its psychometric properties using Rasch analysis.  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