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   32834篇
  免费   2838篇
  国内免费   801篇
耳鼻咽喉   173篇
儿科学   922篇
妇产科学   633篇
基础医学   1610篇
口腔科学   277篇
临床医学   3551篇
内科学   6084篇
皮肤病学   251篇
神经病学   4301篇
特种医学   505篇
外科学   3045篇
综合类   4147篇
预防医学   6611篇
眼科学   217篇
药学   2774篇
  19篇
中国医学   206篇
肿瘤学   1147篇
  2024年   90篇
  2023年   679篇
  2022年   1576篇
  2021年   1783篇
  2020年   1665篇
  2019年   1380篇
  2018年   1384篇
  2017年   1422篇
  2016年   1554篇
  2015年   1441篇
  2014年   2983篇
  2013年   2942篇
  2012年   2411篇
  2011年   2606篇
  2010年   1852篇
  2009年   1657篇
  2008年   1588篇
  2007年   1488篇
  2006年   1237篇
  2005年   950篇
  2004年   689篇
  2003年   555篇
  2002年   459篇
  2001年   396篇
  2000年   312篇
  1999年   202篇
  1998年   153篇
  1997年   165篇
  1996年   132篇
  1995年   126篇
  1994年   98篇
  1993年   82篇
  1992年   79篇
  1991年   69篇
  1990年   54篇
  1989年   46篇
  1988年   41篇
  1987年   32篇
  1986年   24篇
  1985年   17篇
  1984年   17篇
  1983年   9篇
  1982年   8篇
  1981年   5篇
  1980年   3篇
  1979年   3篇
  1977年   4篇
  1975年   1篇
  1966年   1篇
  1906年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
目的 :了解慢性老年精神分裂症患者认知功能和日常生活能力状况 ,探讨此类患者在额叶执行功能和记忆方面的神经心理功能障碍及其特征。方法 :采用简易智力状态检查 (MMSE)、日常生活能力量表 (ADL)、威斯康星卡片分类测验 (WCST)及韦氏记忆量表 (WMS)对 31例慢性老年精神分裂症和 31例正常对照组进行比较研究。结果 :慢性老年精神分裂症组MMSE得分明显低于正常对照组 (P <0 .0 1) ;而该组ADL总分明显高于正常对照组(P <0 .0 5 )。除非持续错误外 ,慢性老年精神分裂症患者的威斯康星卡片分类测验和韦氏记忆量表的各项测验成绩均差于对照组 (P <0 .0 5 )。结论 :慢性老年精神分裂症患者认知功能的障碍决定了患者日常生活能力的减退 ;这类患者有明显的额叶执行功能障碍和记忆障碍  相似文献   
52.
A woman's partner and the characteristics of their partnership can play an important role in the health of her pregnancy. Yet, with the notable exception of intimate partner violence, there has been little previous research addressing the associations between partner- or partnership-related factors and birth outcomes. This analysis tested the hypothesis that risk factors related specifically to partner or partnership characteristics increased the risk for preterm birth. Between 2003 and 2005, a total of 580 preterm cases (20–36 weeks gestational age at delivery) and 633 term controls (≥37 weeks) were selected from women delivering at an obstetric hospital in Lima, Peru. Each woman completed a confidential, structured interview and provided biological specimens within 48 h after delivery. Multivariable logistic regression was used to assess associations between partner and partnership characteristics and preterm birth. After adjustment for behavioral, demographic, and obstetric risk factors, ever having had a partner with a history of drug use (aOR = 1.91, 95% CI 1.22–2.99), ever having had anal sex (aOR = 1.40, 95% CI 1.07–1.84), having a current partner with a history of visiting prostitutes (aOR = 1.69, 95% CI 1.22–2.33), and perceiving one's current partner as a “womanizer” (aOR = 1.34, 95% CI 1.02–1.77) were significantly associated with an elevated risk of preterm birth when tested in separate models. These four factors were then used to create a composite partnership risk score, which showed an increasing dose-response relationship with preterm birth risk (per additional partner risk factor: aOR = 1.31, 95% CI 1.16–1.49). These results highlight the importance of considering a broader set of risk factors for preterm birth, specifically those related to a woman's partner and partnership characteristics. Further research could clarify the specific mechanisms through which these partner and partnership characteristics may increase the risk of preterm birth.  相似文献   
53.
The aim of this study was to assess risk behaviors and its association with caries activity and dental caries in Japanese children. The subjects were 392 young Japanese children who underwent dental health check-up at 18, 30 and 42 months of age. Oral examinations, Cariostat tests and dental health questionnaires were carried out at each time. The caries prevalence of children was 1.5% at 18 months, 9.9% at 30 months and 28.1% at 42 months. Caries activity based on the Cariostat scores of children was correlated with caries status (caries-free/carious) at 42 months. In children with caries during each examination period at 42 months, eating snacks while playing was ranked as the most important behavioral risk (P < 0.001), followed by breast-feeding (P < 0.01), non setting of time for snacks (P < 0.05) and frequency of snacks (P < 0.05) at 18 months old; non brushing by mother (P < 0.05) and eating snacks while playing (P < 0.05) were ranked highest at 30 months old. In addition, eating snacks while playing (P < 0.001) at 42 months old was the only a significant factor for children with caries. Caries activity and risk behaviors were associated with caries experience at different age periods of childhood.  相似文献   
54.
目的探讨群体损伤院前急救转运存在的风险与防范对策。方法通过547例群体损伤转运,分析影响安全转运存在的风险,正确评估和判断风险,制定有效的防范措施和对策。结果 547例伤员安全转运入院治疗,入院率100%。结论预见转运存在风险,采取有效防范对策,是确保成功转运的关键因素。  相似文献   
55.
目的 对比分析食管癌病例组与对照组血缘亲属食管癌患病风险,并了解食管癌家族中危险亲属人群患病的新线索.方法 采用病例对照研究方法 ,对食管癌病例组及对照组各720例进行逐层分析,以比较两组各血缘亲属父系、母系食管癌患病危险度(OR)的大小及差异.结果 (1)病例组Ⅰ级亲属食管癌患病危险度(1.34%~2.24%)显著高于对照组(0.78%~1.21%)(P<0.01);Ⅰ级亲属中病例组父母亲食管癌患病危险度为6.11%,显著高于对照组父母亲食管癌患病危险度2.97%(P<0O01).(2)以血缘亲属中父系和母系亲属逐层分析可见,病例组父系食管癌患病危险度(0.87%~1.01%)与母系患病危险度(0.50%~0.79%)均显著高于对照组父系食管癌患病危险度(0.53%~0.65%)与母系患病危险度(0.38%~0.47%)(P<0.05).进一步分析显示,病例组父系中男性亲属与母系中女性亲属,即父系中祖父、父亲、叔伯食管癌患病危险度为2.68%与母系中外祖母、母亲、姨的食管癌患病危险度1.91%均显著高于对照组父系中男性亲属食管癌患病危险度1.50%与母系中女性亲属食管癌患病危险度0.92%(P<0.01).结论 山西省食管癌患者血缘亲属发病危险主要是父亲及其兄弟、母亲及其姐妹,其下代患食管癌风险要大.  相似文献   
56.
BACKGROUND: Facial emotions are central to human interaction. Identifying pathophysiology in affect processing circuitry that supports the ability to assess facial emotions might facilitate understanding of affect regulation in pediatric bipolar disorder. METHODS: Ten euthymic, unmedicated pediatric bipolar patients and 10 healthy control subjects matched for age, gender, race, socioeconomic status, and IQ were scanned with functional magnetic resonance imaging. Angry, happy, and neutral faces were presented in 30-sec blocks, with a 20-sec rest period between blocks. Subjects were asked to press a button when each face appeared, to ensure that attention was maintained on-task. RESULTS: In bipolar patients, in response to both angry and happy faces relative to neutral faces, we observed reduced activation of right rostral ventrolateral prefrontal cortex together with increased activity in right pregenual anterior cingulate, amygdala, and paralimbic cortex. Bipolar patients also showed reduced activation of visual areas in occipital cortex together with greater activation in higher-order visual perceptual areas, including superior temporal sulcus and fusiform gyrus with angry faces and posterior parietal cortex with happy faces. CONCLUSIONS: Findings document a disturbance in affective neurocircuitry in pediatric bipolar disorder. Reduced activation in ventrolateral prefrontal cortex might reflect diminished top-down control that leads to the observed exaggerated activation in amygdala and paralimbic areas. Changes in occipital areas might represent an effort to gate sensory input when affective responses to the faces could not be successfully modulated. Disturbances in affect processing circuitry could contribute to emotional dysregulation and social cognitive difficulties in bipolar youth.  相似文献   
57.
Acetylcholinesterase inhibitors may improve myelin integrity.   总被引:2,自引:0,他引:2  
Recent clinical trials have revealed that cholinergic treatments are efficacious in a wide spectrum of neuropsychiatric disorders that span the entire human lifespan and include disorders without cholinergic deficits. Furthermore, some clinical and epidemiological data suggest that cholinergic treatments have disease modifying/preventive effects. It is proposed that these observations can be usefully understood in a myelin-centered model of the human brain. The model proposes that the human brain's extensive myelination is the central evolutionary change that defines our uniqueness as a species and our unique vulnerability to highly prevalent neuropsychiatric disorders. Within the framework of this model the clinical, biochemical, and epidemiologic data can be reinterpreted to suggest that nonsynaptic effects of cholinergic treatments on the process of myelination and myelin repair contributes to their mechanism of action and especially to their disease modifying/preventive effects. The ability to test the model in human populations with safe and noninvasive imaging technologies makes it possible to undertake novel clinical trial efforts directed at primary prevention of some of the most prevalent and devastating of human disorders.  相似文献   
58.
眼底动脉硬化与血压、血糖、血脂的多元分析与评估   总被引:1,自引:0,他引:1  
目的探讨眼底动脉硬化与血压、血脂、血糖的相关性,评估中风危险度。方法对2004年5月至2008年10月就诊的患者335例,作为观察组,并与无症状的健康体检者180例作对照,动态检测眼底动脉硬化、血压、血糖、血脂的异常变化,并做综合量化评估。结果脑血管疾病与眼底动脉硬化、血压、血糖、血脂等因素密切相关。结论眼底动脉硬化、血糖、血脂、血压异常的量化评分,能够预估中风,以便采取预防性治疗。  相似文献   
59.
申小青  李爽 《现代护理》2006,12(29):2784-2785
目的了解鼻窦炎患儿家长对儿童鼻窦炎相关知识的认知情况,为进一步加强卫生宣教、预防儿童鼻窦炎提供理论依据。方法对65名鼻窦炎患儿家长进行关于儿童鼻窦炎发病因素、临床表现、并发症以及对儿童生长发育影响等问题的问卷调查。结果调查显示95.4%的家长对儿童鼻窦炎知识缺乏了解,且知识获得途径单一。结论应通过各种途径加强儿童鼻窦炎知识的宣教,积极预防儿童鼻窦炎。  相似文献   
60.
We evaluated anti-Toxoplasma gondii IgM-reactive pregnant women seen at a high-risk pregnancy outpatient clinic. From March 2005 to January 2008 in Paraná, Brazil, pregnant women seen by the Brazilian Public Health System, in any gestational period, who were anti-T. gondii IgM-positive, were followed. Clinical symptoms were noted, and tests performed including IgA, IgG avidity, ultrasonogram, and amniocentesis (PCR/inoculation in mice). Of 75 patients, 8 showed low, 3 intermediate and 31 high IgG avidity. Of those who underwent the avidity test, 31 (70.5%) were in the second trimester of pregnancy. Thirty-two (42.7%) pregnant women received specific treatment. Six received triple combination treatment; in three, tachyzoites were isolated, although only one was PCR-positive, showing changes in the cerebral sonogram, borderline IgA, and the Sabin tetrad. One fetus died, and one non-reactive IgM pregnant woman showed ocular recurrence. The municipality of residence, contact with cats during adulthood, and ingestion of unpasteurized milk were shown to be important risk factors. Congenital toxoplasmosis was observed in a pregnancy referred late for treatment. Follow-up of children born to mothers with diagnosed or suspected acute toxoplasmosis is crucial in the management of the changes that toxoplasmosis may cause.  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