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   4370214篇
  免费   368792篇
  国内免费   14762篇
耳鼻咽喉   60860篇
儿科学   140287篇
妇产科学   115523篇
基础医学   668643篇
口腔科学   123064篇
临床医学   396919篇
内科学   792397篇
皮肤病学   105947篇
神经病学   369318篇
特种医学   175520篇
外国民族医学   742篇
外科学   667571篇
综合类   131973篇
现状与发展   24篇
一般理论   2606篇
预防医学   368599篇
眼科学   102288篇
药学   308993篇
  24篇
中国医学   11447篇
肿瘤学   211023篇
  2021年   55938篇
  2019年   58633篇
  2018年   73639篇
  2017年   56225篇
  2016年   62338篇
  2015年   75688篇
  2014年   110224篇
  2013年   175491篇
  2012年   117300篇
  2011年   121296篇
  2010年   123976篇
  2009年   126117篇
  2008年   108326篇
  2007年   114804篇
  2006年   124172篇
  2005年   119183篇
  2004年   121205篇
  2003年   111250篇
  2002年   100250篇
  2001年   159717篇
  2000年   155657篇
  1999年   143567篇
  1998年   71900篇
  1997年   68055篇
  1996年   66342篇
  1995年   62044篇
  1994年   56083篇
  1993年   52233篇
  1992年   108336篇
  1991年   104479篇
  1990年   100209篇
  1989年   97592篇
  1988年   90689篇
  1987年   89020篇
  1986年   84573篇
  1985年   83430篇
  1984年   69717篇
  1983年   61900篇
  1982年   49372篇
  1981年   45832篇
  1980年   43152篇
  1979年   61693篇
  1978年   49342篇
  1977年   43460篇
  1976年   40509篇
  1975年   40141篇
  1974年   44872篇
  1973年   43202篇
  1972年   40213篇
  1971年   37253篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
ABSTRACT

Forest workers, including loggers, foresters, and wildland firefighters, are regularly exposed to some of the most fatal occupational environments in the United States. These hazardous work environments may become even more complex and dynamic when subject to bark beetle outbreaks that have resulted in significant tree mortality. The impacts of tree death from bark beetles are significant, with the cumulative 17-year (2000–2016) footprint for bark beetle caused tree mortality estimated at 54 million acres. However, how workers think about and act in these environments is understudied. This study, therefore, approaches the issue of beetle kill and forest worker safety by examining the perspectives or workers themselves. Its contribution is to leverage ethnographic research to provide insights that can generate new research questions, better inform outreach, and ultimately improve worker safety outcomes. The resulting insights show that beetle kill was understood by workers as a hazard that increased the complexity and dynamism of the work environment, making situational awareness both more necessary and more difficult to maintain. While much research about situational awareness focuses on hazardous situations, it is suggested that building adequate situational awareness should also include broader considerations of organizational communication, as well as training and experience considered over the course of entire careers.  相似文献   
993.
994.
Trichotillomania is a form of traction alopecia resulting from repetitive and compulsive hair pulling and plucking. Trichotillomania and patchy alopecia areata may have similar clinical and dermoscopic features in some cases. On trichoscopic examination, the presence of black dots, coiled or hook hair, shafts of varying lengths with fraying or split ends (trichoptilosis), and an absence of exclamation mark hairs and yellow dots are suggestive of trichotillomania.  相似文献   
995.
Objective: The objective of this study was to gain greater insight into individuals’ quality of life (QOL) definitions, appraisals, and adaptations following spinal cord injury (SCI).

Design: A mixed-methods design, applying the Schwartz and Sprangers response shift (RS) model. RS is a cognitive process wherein, in response to a change in health status, individuals change internal standards, values, or conceptualization of QOL

Setting: Community-dwelling participants who receive medical treatment at a major Midwestern medical system and nearby Veterans’ Affairs hospital.

Participants: A purposive sample of participants with SCI (N?=?40) completed semi-structured interviews and accompanying quantitative measures.

Interventions: Not applicable.

Outcome Measures: Qualitative data were analyzed using content analysis to identify themes. Analysis of variance were performed to detect differences based on themes and QOL, well-being, and demographic and injury characteristics.

Results: Four RS themes were identified, capturing the range of participant perceptions of QOL. The themes ranged from complete RS, indicating active engagement in maintaining QOL, to awareness and comparisons redefining QOL, to a relative lack of RS. Average QOL ratings differed as a function of response shift themes. PROMIS Global Health, Anxiety, and Depression also differed as a function of RS themes.

Conclusion: The RS model contextualizes differences in QOL definitions, appraisals, and adaptations in a way standardized QOL measures alone do not.  相似文献   

996.

Objective

The teaching hospital of Nancy, France, implemented a specific multidisciplinary care pathway (French acronym AMDPL) to improve the management of patients presenting with Lyme borreliosis (LB) suspicion. We aimed to assess the first year of activity of this care pathway.

Patients and methods

We included all patients managed in the AMDPL pathway from November 1, 2016 to October 31, 2017. The first step was a dedicated Lyme disease consultation with an infectious disease specialist. Following this consultation, the LB diagnosis was either confirmed and adequate treatment was prescribed, or a differential diagnosis was established and patients received adequate management, or further investigations were required and patients were offered multidisciplinary management as part of a day hospitalization.

Results

A total of 468 patients were included. LB diagnosis was confirmed in 15% of patients (69/468), 49% of patients received a differential diagnosis, and 26% (122/468) of patients had the LB diagnosis ruled out without receiving any other diagnosis.

Conclusions

This is to our knowledge the first multidisciplinary center implemented in France for the management of patients presenting with LB suspicion related to polymorphous signs and symptoms. Several diagnoses could be confirmed or corrected, although some symptoms and complaints could not be explained. This cohort could improve our knowledge of LB and its differential diagnoses.  相似文献   
997.
Objective: To determine serotonin system abnormalities related to major depression or previous suicidal behavior.

Methods: [11C]WAY100635, [18F]altanserin and positron emission tomography were used to compare 5-HT1A and 5-HT2A binding in MDD patients divided into eight past suicide attempters (>4yrs prior to scanning) and eight lifetime non-attempters, and both groups were compared to eight healthy volunteers.

Results: The two receptor types differed in binding pattern across brain regions from each other, but there were no differences in binding between healthy volunteers and the two depressed groups or between depressed suicide attempters and non-attempters. No effects of depression severity or lifetime aggression were observed for either receptor.

Conclusion: Limitations of this study include small sample size and absence of high lethality suicide attempts in the depressed attempter group. No trait-like binding correlations with past suicide attempt or current depression were observed. Given the heterogeneity of nonfatal suicidal behavior, a larger sample study emphasizing higher lethality suicide attempts may find the serotonin biological phenotype seen in suicide decedents.  相似文献   

998.
999.
Struan H. Coleman 《Arthroscopy》2019,35(4):1109-1110
Dancers have a disproportionately high prevalence of hip issues compared with other types of athletes. Many of these hip issues are complex: a cam and/or pincer impingement combined with a seemingly paradoxical borderline dysplasia, capsular laxity, and subsequent instability. Our experience as nonarthritic hip surgeons tells us that careful patient selection is critical for a successful outcome after the arthroscopic treatment of a dancer. But, there is little guidance in the literature on the management of this specific group of patients. We have studies that advise us to repair the labrum when possible versus performing labral debridement in female patients with predominantly pincer-type impingement and studies that support capsular plication and careful capsule closure in patients, predominantly female patients, with combined hip impingement and dysplasia or borderline dysplasia. However, few studies have examined predictors of outcomes after hip arthroscopy in dancers.  相似文献   
1000.
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