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   2067篇
  免费   95篇
  国内免费   2篇
耳鼻咽喉   24篇
儿科学   77篇
妇产科学   41篇
基础医学   247篇
口腔科学   151篇
临床医学   347篇
内科学   318篇
皮肤病学   130篇
神经病学   165篇
特种医学   33篇
外国民族医学   1篇
外科学   143篇
综合类   18篇
一般理论   1篇
预防医学   242篇
眼科学   20篇
药学   82篇
中国医学   1篇
肿瘤学   123篇
  2024年   5篇
  2023年   15篇
  2022年   16篇
  2021年   17篇
  2020年   25篇
  2019年   39篇
  2018年   29篇
  2017年   38篇
  2016年   45篇
  2015年   49篇
  2014年   81篇
  2013年   139篇
  2012年   103篇
  2011年   147篇
  2010年   69篇
  2009年   71篇
  2008年   141篇
  2007年   139篇
  2006年   111篇
  2005年   115篇
  2004年   115篇
  2003年   119篇
  2002年   105篇
  2001年   16篇
  2000年   13篇
  1999年   17篇
  1998年   23篇
  1997年   22篇
  1996年   23篇
  1995年   42篇
  1994年   24篇
  1993年   23篇
  1992年   10篇
  1991年   16篇
  1990年   21篇
  1989年   5篇
  1988年   16篇
  1987年   10篇
  1986年   17篇
  1985年   10篇
  1984年   13篇
  1983年   14篇
  1982年   15篇
  1981年   11篇
  1980年   9篇
  1979年   9篇
  1978年   5篇
  1977年   7篇
  1976年   10篇
  1974年   7篇
排序方式: 共有2164条查询结果,搜索用时 109 毫秒
51.
52.
53.
The Senegalese sole (Solea senegalensis) is a high value market flatfish, which aquaculture is compromised by severe reproductive problems; these are mostly found in soles hatched and raised in captivity (F1 generation). To gain knowledge on the reproductive dysfunctions observed in cultured (F1) Senegalese sole, this work aimed at developing a specific vitellogenin (VTG) ELISA, for the measurement of plasma VTG levels in this species. Profiles of VTG were correlated with those of sexual steroids and spawning performance of an F1 broodstock, during three consecutive years. The Senegalese sole VTG (ssVTG) was purified by precipitation with MgCl(2)-EDTA and anion-exchange chromatography and showed a molecular mass of 172 kDa, by SDS-PAGE. Specific antibodies were obtained and used to develop a competitive ELISA, which had a sensitivity of 3.6 ng ml(-1), and inter- and intra-assay coefficients of variation of 9.5% (n=29) and 6.7% (n=12), respectively. Annual profiles of plasma VTG showed a major peak at pre-spawning, and a second minor rise around autumn, which mirrored plasma profiles of both estradiol (E(2)) and testosterone (T) levels. Spontaneous spawning occurred every year in the spring season, but no fertilized eggs were obtained. In conclusion, this study described, for the first time, the purification and development of a sensitive and specific ELISA for Senegalese sole VTG. The endocrine and spawning data suggested that F1 female broodstock showed normal VTG and steroid releasing profiles in captivity with occurrence of spontaneous spawning, but no fertilization of the eggs was recorded.  相似文献   
54.
Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, beta-N-methylamino-L-alanine, may be produced by all known groups of cyanobacteria, including cyanobacterial symbionts and free-living cyanobacteria. The ubiquity of cyanobacteria in terrestrial, as well as freshwater, brackish, and marine environments, suggests a potential for wide-spread human exposure.  相似文献   
55.
Pain as a result of cervical radiculopathy (CR) can be widespread, nondermatomal and individually specific, but the association between pain extent and other clinical features has never been explored. The objective of this study is to investigate whether pain extent relates to clinical variables including pain intensity in addition to health indicators including disability, general health, depression, somatic anxiety, coping strategies or self-efficacy.An observational cohort study was conducted. Participants were recruited from 4 hospital spinal centres in Sweden. Pain extent was quantified from the pain drawings of 190 individuals with cervical disc disease, verified with magnetic resonance imaging (MRI) and compatible with clinical findings (examined by a neurosurgeon), that show cervical nerve root compression. Pain extent was evaluated in relation to neck pain, arm pain, and headache intensity. Multiple linear regression analysis were then used to verify whether pain extent was associated with other health indicators including disability, health-related quality of life, depression, somatic anxiety, coping strategies and self-efficacy.Pain extent was directly related to neck, arm and headache pain intensity (all P < .01). Multiple linear regression revealed that pain extent was significantly associated only to the level of perceived disability (P < .01).Increased pain extent in people with CR is associated with higher headache, neck and arm pain intensity, and disability but not measures of general health, depression, somatic anxiety, coping strategies or self-efficacy.  相似文献   
56.
57.
Purpose: The purpose was to investigate how physical function is assessed in people with musculoskeletal disorders (MSD) in the neck. Specifically, we aimed to determine: (1) Which questionnaires are used to assess physical function in people with MSD in the neck? (2) What do those questionnaires measure? (3) What are the measurement properties of the questionnaires?

Materials and methods: A systematic review was performed to identify questionnaires and psychometric evaluations. The content of the questionnaires was categorized according to the International Classification of Function, Disability and Health, and the psychometric properties were quality-rated using the COnsensus-based Standards for the selection of health Measurement INstruments checklist.

Results: Ten questionnaires and 32 articles evaluating measurement properties were analyzed. Most questionnaires covered only the components body functions and activity and participation, more often activity participation than body function. Internal consistency was adequate in most questionnaires, whereas responsiveness was generally low. Neck Disability Index was most evaluated, but the evaluations of all questionnaires tended to cover most properties in the checklist.

Conclusions: The questionnaires differed substantially in items and extent to which their psychometric properties had been evaluated. Focus of measurement was on activities in daily life rather than physical function as such.
  • Implications for Rehabilitation
  • To provide early diagnostics and effective treatment for patients with neck disorders, valid and reliable instruments that measure relevant aspects of the disorders are needed.

  • This paper presents an overview of content and quality of questionnaires used to assess physical function in neck disorders, which may facilitate informed decisions about which measurement instruments to use when evaluating the course of neck disorders.

  • Most of the questionnaires need more testing to judge the quality, however the NDI was the most frequently tested questionnaire.

  • The COnsensus-based Standards for the selection of health Measurement INstruments checklist is a useful tool in relation to psychometric testing of questionnaires, but clear definitions of interpretation of the quality criteria in each study would enhance comparability of results.

  相似文献   
58.
59.
Clinical Oral Investigations - To evaluate the effectiveness of surgical and nonsurgical treatment of temporomandibular joint (TMJ) luxation. This systematic literature review searched PubMed, the...  相似文献   
60.
Clinical Oral Investigations - Pain in the orofacial region may originate from different structures, and one challenge for the clinician is to determine the primary origin of pain reported by the...  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