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   4550篇
  免费   275篇
  国内免费   50篇
耳鼻咽喉   544篇
儿科学   252篇
妇产科学   55篇
基础医学   315篇
口腔科学   235篇
临床医学   597篇
内科学   474篇
皮肤病学   19篇
神经病学   135篇
特种医学   196篇
外科学   662篇
综合类   371篇
预防医学   528篇
眼科学   10篇
药学   96篇
  2篇
中国医学   159篇
肿瘤学   225篇
  2024年   10篇
  2023年   86篇
  2022年   145篇
  2021年   217篇
  2020年   170篇
  2019年   256篇
  2018年   290篇
  2017年   192篇
  2016年   182篇
  2015年   137篇
  2014年   387篇
  2013年   303篇
  2012年   260篇
  2011年   297篇
  2010年   217篇
  2009年   213篇
  2008年   224篇
  2007年   212篇
  2006年   169篇
  2005年   128篇
  2004年   91篇
  2003年   76篇
  2002年   68篇
  2001年   52篇
  2000年   45篇
  1999年   43篇
  1998年   36篇
  1997年   29篇
  1996年   27篇
  1995年   16篇
  1994年   29篇
  1993年   23篇
  1992年   23篇
  1991年   22篇
  1990年   13篇
  1989年   9篇
  1988年   18篇
  1987年   13篇
  1986年   6篇
  1985年   22篇
  1984年   29篇
  1983年   14篇
  1982年   15篇
  1981年   13篇
  1980年   10篇
  1979年   13篇
  1978年   4篇
  1977年   5篇
  1975年   4篇
  1971年   3篇
排序方式: 共有4875条查询结果,搜索用时 15 毫秒
51.
The primary purpose of this investigation was to evaluate the relationship between milk-fat intake and obesity, particularly abdominal obesity, in 13,544 U.S. adults. A lesser objective was to measure the degree to which the association was influenced by multiple potential confounding variables. This cross-sectional study used data from the 2011–2016 National Health and Nutrition Examination Survey (NHANES). Quantity of milk-fat regularly consumed was the exposure variable. Sagittal abdominal diameter (SAD), a measure of abdominal obesity, and body mass index (BMI) were the outcome variables. Sagittal abdominal diameter is a strong predictor of visceral abdominal fat, when measured by computed tomography, and has been shown to predict cardiometabolic disorders better than BMI. After controlling for age, race, gender, physical activity, leisure computer use and gaming, alcohol habits, and cigarette use, significantly lower BMIs were associated with consistent non-fat and full-fat milk consumption (F = 4.1, p = 0.0063). A significantly lower SAD was associated only with regular consumption of non-fat milk (F = 5.0, p = 0.0019). No significant differences were detected between the other milk-fat groups or milk abstainers. In this nationally representative sample, only 19.6% of adults regularly consumed low-fat milk. In conclusion, consistent non-fat milk intake was predictive of lower levels of abdominal adiposity compared to consumption of higher levels of milk-fat.  相似文献   
52.
ObjectiveThe 2019 Asian Working Group on Sarcopenia in Older People (AWGS 2019) recommends using either calf circumference or the strength, assistance in walking, rising from a chair, climbing stairs, and falls (SARC-F) or SARC-F combined with calf circumference (SARC-CalF) questionnaires for sarcopenia screening. The aim of this study was to compare the ability and applicability of calf circumference, SARC-F, and SARC-CalF for screening sarcopenia among community-dwelling older adults.DesignCross-sectional study.Setting and ParticipantsA total of 1050 community-dwelling older people were enrolled.MethodsSarcopenia was diagnosed according to the AWGS 2019 criteria: bioimpedance analysis for appendicular skeletal muscle index, hand grip, and 6-m gait speed test. Participants also completed the SARC-F questionnaire and calf circumference measurement. The screening tools’ performances were evaluated through receiver operating characteristic (ROC) curves, area under the ROC curves (AUC), and sensitivity/specificity analyses.ResultsSarcopenia was identified in 263 (25.0%) participants by the AWGS 2019 criteria. Calf circumference had a sensitivity of 81.4% and a specificity of 77.0%. Sensitivity and specificity of SARC-F for screening sarcopenia were 17.9% and 93.7%, respectively. SARC-CalF improved the sensitivity of SARC-F (47.5%) while keeping similar specificity (92.0%). The AUCs of calf circumference, SARC-F, and SARC-CalF were 0.79 [95% confidence interval (CI), 0.77–0.82], 0.56 (95% CI, 0.52–0.59), and 0.70 (95% CI, 0.67–0.73), respectively. The differences across ROC curves were statistically significant among 3 screening tools (P < .001).Conclusions and ImplicationsThe overall screening ability of calf circumference was better than that of SARC-F and SARC-CalF for sarcopenia in community-dwelling older persons despite gender, age, and cognitive function. SARC-F and SARC-CalF have high specificity but are susceptible to the preceding factors.  相似文献   
53.
目的分析海口市7~14岁儿童在超重和肥胖层面的腰围界值点,为儿童超重和肥胖防治策略制定提供科学依据。方法利用2016—2019年“海南省学生健康档案管理系统”,采用PPS抽样方法抽取海口220所中小学校,对学校整群抽样7~14岁儿童调取身高、体重和腰围数据进行整理分析。结果共计分析283054名7~14岁儿童,各年龄组儿童的平均腰围值和百分位点腰围值均低于全国平均腰围,腰围均随着年龄增长而持续增加。各年龄组儿童腰围男生均大于女生(P<0.0001),城市均高于农村(P<0.0001)。在超重层面,男童和女童界值点集中P 75~P 80(56.50~71.75 cm)、P 80~P 85(54.50~68.50 cm)。在肥胖层面,男童7~11岁和12~14岁的界值点分别是P 85(58.5~72.50 cm)、P 90(75.50~79.50 cm),女生7岁和8~14岁的界值点范围在分别是P 85(56.50 cm)和P 90(59.85~71.50 cm)。结论该地区在超重层面,男童和女童的界值点分别为56.50~71.75 cm和54.50~68.50 cm;肥胖层面,男童和女童的界值点分别是58.50~79.50 cm和56.50~71.50 cm。除了男生7岁和女生9岁超重界值点及女生青春期前8~10岁肥胖界值点外,其他各年龄组超重和肥胖界值点与全国的一致。  相似文献   
54.
儿童期肥胖增加血脂异常、高血压、高血糖等心血管代谢风险(CMR),并可持续至成人,使代谢性疾病低龄化。近年发现,尿酸、视黄醇结合蛋白4、维生素D、颈围等与肥胖儿童CMR密切相关,可作为CMR的预警指标,为心血管代谢疾病的早期防治提供新靶标。认识预警指标与代谢风险的关系、作用机制和临床意义,有助于早期识别有CMR相关因素的高危人群并进行干预。  相似文献   
55.
目的:总结颈部囊肿与瘘管的诊治经验。方法:93例行手术治疗,其中鳃裂囊肿15例,鳃裂瘘管10例,皮样囊肿1例,囊状淋巴管瘤4例,甲状舌骨囊肿37例,甲状舌管瘘管25例,癌性淋巴液囊肿1例,随访1-10年。结果:93例中,囊性淋巴管瘤1例复发后失访,另1例行2次手术,癌性淋巴液囊肿1例半年后死于肺转移,鳃裂瘘管2例3次手术,甲状舌管瘘管1例复发,鳃裂瘘管术后1例迟发性面瘫,一次手术治愈,无术后并发症。结论:颈部囊肿与瘘管的诊断除依据术前检查外,主要是依据术中的发现和术后病理检查。B超、CT等是有效的辅助检查.手段治疗上应彻底切除囊壁与瘘管,避免复发。术中应避免损伤颈部的大血管和神经。甲状舌管瘘管须切除舌骨中段2cm,这是防止术后复发的关键。  相似文献   
56.
背景与目的 淋巴漏为颈部淋巴结清扫术后常见并发症,传统治疗方法作用相对有限,而铜绿假单胞菌注射液处理创面可较好促进局部炎症反应以闭合漏点,因此本研究分析铜绿假单胞菌注射液对甲状腺乳头状癌(PTC)颈侧区淋巴结清扫术后淋巴漏患者引流量的影响及安全性,以明确铜绿假单胞菌注射液的应用价值。方法 回顾性分析2019年1月—2020年1月郑州大学第一附属医院甲状腺外科行颈侧区淋巴结清扫术后出现淋巴漏的69例PTC患者资料,依据淋巴漏治疗方式不同将其分为对照组(37例,术中常规双侧留置负压引流)、观察组(32例,在对照组治疗的基础上,术后第4、6天,通过引流管注入2支铜绿假单胞菌注射液),比较两组术后引流量、体温变化,记录其引流时间及不良反应发生率。结果 两组术后第1、2、3天引流量比较差异无统计学意义(均P>0.05),观察组术后第4、5、6天引流量低于对照组[(310.79±32.16)mL vs.(338.64±34.55)mL、(157.82±16.43)mL vs.(325.43±33.96)mL、(87.34±8.59)mL vs.(333.68±34.59)mL,均P<0.05];观察组术后第6、7 天体温高于对照组[(37.78±3.77)℃ vs.(35.96±3.60)℃、(37.65±3.72)℃ vs.(35.79±3.68)℃,均P<0.05],其他时点两组体温差异均无统计学意义(均P>0.05);观察组引流时间明显短于对照组[(6.17±0.63)d vs.(7.28±0.75)d,P<0.01];观察组部分患者术后2周内出现局部发热、寒战不良反应,予以物理降温后均恢复正常,观察组术后不良反应发生率高与对照组(12.50% vs. 8.11%),但差异无统计学意义(P>0.05)。结论 铜绿假单胞菌注射液治疗PTC患者颈侧区淋巴结清扫术后淋巴漏患者临床效果较好,可降低引流量,缩短引流时间,部分患者可能有体温升高、发热等现象,经对症处理后均可缓解,不影响治疗。  相似文献   
57.
Context: The purpose of this report is to describe the clinical decision-making process for a patient with rheumatoid arthritis with neck pain with underlying atlantoaxial instability.Findings: The patient was evaluated for worsening upper neck pain that began insidiously 1 year prior. The patient denied numbness or tingling in her upper or lower extremities, dizziness or lightheadedness, difficulty maintaining balance with walking, or muscle weakness. Cervical spine range of motion was limited in all planes due to pain and apprehension. The patient’s neurological examination was unremarkable. Prior flexion and extension radiographs of the cervical spine were interpreted as unremarkable with alignment preserved in flexion and extension. However, upon further inspection, the cervical spine flexion radiograph was concerning for inadequate cervical motion, which may have limited the diagnostic utility of these radiographs. Additionally, a Sharp-Purser test was performed, which was positive for excessive motion. Flexion and extension radiographs of the cervical spine were then repeated ensuring the patient adequately flexed and extended during the imaging. Severe anterior subluxation of C1 relative to C2 with cervical flexion was noted, as C1 moved as much as 8–9 mm anterior to C2 with cervical flexion. Given the degree of atlantoaxial instability, the patient subsequently underwent successful posterior fusion from the occiput to C2.Conclusion/Clinical Relevance: This case report demonstrates the importance of properly screening for upper cervical spine instability in patients with rheumatoid arthritis and neck pain and understanding the importance of obtaining adequate and appropriate diagnostic imaging.  相似文献   
58.
ObjectiveTo evaluate the effects of myofascial trigger point release applied to superficial neck muscles and strengthening of the deep flexor muscles in subjects with myofascial temporomandibular disorders (mTMD).MethodsFourteen women (23.4 ± 3.32 years old) presenting with mTMD and trigger points (TrPs) in the sternocleidomastoid, suboccipital, and upper trapezius muscles were included in this study. They were evaluated on two occasions during a baseline period (3 weeks apart) with no intervention and a third time after a 5-weeks intervention protocol. Outcome measures included pressure pain threshold (PPT) over the masticatory muscles, mandibular function, orofacial pain intensity, maximum mouth opening, and the craniocervical flexion test. All women received 10 treatment sessions that included strain-counterstrain technique applied to TrPs found in the prior listed superficial neck muscles and stabilization exercise using a pressure biofeedback for the deep neck flexor muscles. One-way ANOVA or correspondent non-parametric tests as well as effects sizes were used to compare the outcomes at baseline and after the treatment.ResultsStatistically significant improvements were found in the PPT over left masseter and temporalis (p < 0.05) (mean difference (MD) of 0.50 and 0.42 kg/cm2), orofacial pain intensity (MD = −3.39 points), mandibular function (MD = −7.22 points) and performance of the deep cervical muscles (MD = 130.42 points) compared to baseline period. Effect sizes were moderate or large.ConclusionThe protocol intervention may have positive effects in patients with mTMD. However, studies with better methodological quality need to be performed to confirm those effects.Registrationensaiosclinicos.gov.br (RBR-7x828q);  相似文献   
59.
Summary The otolith contribution and otolith-visual interaction in eye and head stabilization were investigated in alert cats submitted to sinusoidal linear accelerations in three defined directions of space: up-down (Z motion), left-right (Y motion), and forward-back (X motion). Otolith stimulation alone was performed in total darkness with stimulus frequency varying from 0.05 to 1.39 Hz at a constant half peak-to-peak amplitude of 0.145 m (corresponding acceleration range 0.0014–1.13 g) Optokinetic stimuli were provided by sinusoidally moving a pseudorandom visual pattern in the Z and Y directions, using a similar half peak-to-peak amplitude (0.145 m, i.e., 16.1°) in the 0.025–1.39 Hz frequency domain (corresponding velocity range 2.5°–141°/s). Congruent otolith-visual interaction (costimulation, CS) was produced by moving the cat in front of the earth-stationary visual pattern, while conflicting interaction was obtained by suppressing all visual motion cues during linear motion (visual stabilization method, VS, with cat and visual pattern moving together, in phase). Electromyographic (EMG) activity of antagonist neck extensor (splenius capitis) and flexor (longus capitis) muscles as well as horizontal and vertical eye movements (electrooculography, EOG) were recorded in these different experimental conditions. Results showed that otolith-neck (ONR) and otolith-ocular (OOR) responses were produced during pure otolith stimulation with relatively weak stimuli (0.036 g) in all directions tested. Both EMG and EOG response gain slightly increased, while response phase lead decreased (with respect to stimulus velocity) as stimulus frequency increased in the range 0.25–1.39 Hz. Otolith contribution to compensatory eye and neck responses increased with stimulus frequency, leading to EMG and EOG responses, which oppose the imposed displacement more and more. But the otolith system alone remained unable to produce perfect compensatory responses, even at the highest frequency tested. In contrast, optokinetic stimuli in the Z and Y directions evoked consistent and compensatory eye movement responses (OKR) in a lower frequency range (0.025–0.25 Hz). Increasing stimulus frequency induced strong gain reduction and phase lag. Oculo-neck coupling or eye-head synergy was found during optokinetic stimulation in the Z and Y directions. It was characterized by bilateral activation of neck extensors and flexors during upward and downward eye movements, respectively, and by ipsilateral activation of neck muscles during horizontal eye movements. These visually-induced neck responses seemed related to eye velocity signals. Dynamic properties of neck and eye responses were significantly improved when both inputs were combined (CS). Near perfect compensatory eye movement and neck muscle responses closely related to stimulus velocity were observed over all frequencies tested, in the three directions defined. The present study indicates that eye-head coordination processes during linear motion are mainly dependent on the visual system at low frequencies (below 0.25 Hz), with close functional coupling of OKR and eye-head synergy. The otolith system basically works at higher stimulus frequencies and triggers Synergist OOR and ONR. However, both sensorimotor subsystems combine their dynamic properties to provide better eyehead coordination in an extended frequency range and, as evidenced under VS condition, visual and otolith inputs also contribute to eye and neck responses at high and low frequency, respectively. These general laws on functional coupling of the eye and head stabilizing reflexes during linear motion are valid in the three directions tested, even though the relative weight of visual and otolith inputs may vary according to motion direction and/or kinematics.  相似文献   
60.
目的:追踪观察鼻咽癌放疗后颈部残留灶的消退时间,并分析其影响因素。方法:选取1998年5月-2002年6月鼻咽癌放疗后有颈部残留的患者60例,追踪观察其消退时间,并应用Logistic回归分析研究年龄、性别、临床分期等7个因素对其消退时间的影响。结果:80%的患者颈部残留灶可以在放疗结束后3个月内消退。单因素Logistic回归分析显示性别、N分期、化疗3个因素与颈部残留灶的消退有关;多因素Logistic回归分析表明仅有N分期、化疗2个因素影响颈部残留灶的消退。化疗与颈部残留灶的消退时间呈正相关,而N分期则与消退时间呈负相关。结论:鼻咽癌放疗后颈部残留灶大部分可在放疗结束后3个月内消退,影响消退的因素主要有N分期及化疗。  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