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   49389篇
  免费   3519篇
  国内免费   1356篇
耳鼻咽喉   397篇
儿科学   1656篇
妇产科学   1677篇
基础医学   5062篇
口腔科学   1256篇
临床医学   7878篇
内科学   5710篇
皮肤病学   596篇
神经病学   2166篇
特种医学   2360篇
外国民族医学   20篇
外科学   3529篇
综合类   10753篇
现状与发展   11篇
一般理论   2篇
预防医学   3057篇
眼科学   999篇
药学   2315篇
  80篇
中国医学   1323篇
肿瘤学   3417篇
  2024年   33篇
  2023年   607篇
  2022年   1034篇
  2021年   1731篇
  2020年   2014篇
  2019年   1446篇
  2018年   1421篇
  2017年   1473篇
  2016年   1837篇
  2015年   1627篇
  2014年   3116篇
  2013年   3236篇
  2012年   2863篇
  2011年   3066篇
  2010年   2491篇
  2009年   2420篇
  2008年   2372篇
  2007年   2651篇
  2006年   2472篇
  2005年   2165篇
  2004年   1929篇
  2003年   1689篇
  2002年   1384篇
  2001年   1278篇
  2000年   961篇
  1999年   803篇
  1998年   623篇
  1997年   615篇
  1996年   568篇
  1995年   545篇
  1994年   492篇
  1993年   446篇
  1992年   355篇
  1991年   333篇
  1990年   299篇
  1989年   239篇
  1988年   279篇
  1987年   227篇
  1986年   183篇
  1985年   186篇
  1984年   121篇
  1983年   80篇
  1982年   102篇
  1981年   89篇
  1980年   86篇
  1979年   76篇
  1978年   60篇
  1977年   27篇
  1976年   34篇
  1975年   36篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
51.
Stellate ganglion (SG) modification has been investigated for arrhythmia treatment. In this study, transesophageal SG imaging and intervention were explored using a homemade 30F integrated focused ultrasonic catheter in healthy mongrel canines in vivo. Anatomic details of SGs were ultrasonically imaged and evaluated. SG had a heterogeneous echoic structure and characteristic profiles sketched by hyper-echoic outlines in an ultrasonogram. Left SGs in the experimental group were successfully ablated through the esophagus under ultrasonic guidance provided by the catheter itself. Two weeks after the ablation, the QT and QTc of the experimental group decreased compared with those of the sham group and at baseline (both p values < 0.001). Histologic examination revealed that left SGs were destroyed. No major complications were observed. This approach may be further explored as a method for ganglia remodeling evaluation and as a strategy of ganglia modification for arrhythmia and for other diseases.  相似文献   
52.
A pulmonary artery (PA) sling is a very rare congenital cardiovascular anomaly, and only a few studies have reported PA slings in fetuses. The relationship of the PA, aorta, ductus arteriosus, and trachea can be evaluated in the 3‐vessel and 3‐vessel and trachea views during fetal echocardiography. A PA sling can be detected by abnormal positioning of the left PA in relation to the trachea when sweeping from the 3‐vessel view cranially to the 3‐vessel and trachea view. Here we report 3 cases of fetal PA slings and their follow‐ups. Two cases were confirmed by postnatal echocardiography, and the other case was confirmed by a cardiovascular cast after pregnancy termination. We emphasize that the 3‐vessel and 3‐vessel and trachea views are of crucial importance in the prenatal diagnosis of a PA sling.  相似文献   
53.
54.
‘Paediatric bipolar disorder’ (PBD) remains controversial; because it is based on the hypothesis that bipolar disorder (BD) often begins in childhood with atypical forms of mania. A meta-analysis of 12 epidemiological surveys found a high prevalence of PBD among children and adolescents worldwide (1.8%), however, our study of the measurement issues (Child and Adolescent Mental Health, 23, 2018, 14) found that PBD rates were lower than claimed. Our findings are consistent with the developmental trajectory of BD, as described by most longitudinal studies of high-risk offspring. BD is extremely rare in childhood with nearly all index manic/hypomanic episodes being in midadolescence or later. Treatment for BD should not commence until the first well-defined manic/hypomanic episode, because children and younger adolescents are extremely sensitive to the side effects of second-generation antipsychotics including weight gain, metabolic syndrome, extrapyramidal side effects and the risk of cerebral atrophy, as observed in studies of juvenile animals.  相似文献   
55.
ObjectivesEarly diagnosis of cognitive impairment is increasingly emphasized in the literature to facilitate timely preventive interventions. Although bedside cognitive tests such as the Montreal Cognitive Assessment (MoCA) are widely used for such early diagnostic purposes, they may not have comparable performance to a full neuropsychological battery (FNB) in diagnosing early cognitive impairment. This study investigated whether a small subset of neuropsychological tests can be added on to MoCA to match its performance to that of the FNB in discriminating mild cognitive impairment and dementia (MCI/dementia) from normal cognition.DesignCross-sectional diagnostic study.SettingAlzheimer's Disease Centers across the United States.ParticipantsOlder participants (≥50 years) who completed MoCA and the FNB (N = 9187).MeasuresThe study sample was split into two: the derivation sample (n = 1837) was used to develop a brief neuropsychological battery that best discriminated MCI/dementia (using the best-subset approach with 10-fold cross-validation); while the validation sample (n = 7350) verified its actual performance in discriminating MCI/dementia.ResultsA 3-item neuropsychological battery was identified, comprising MoCA, Benson Complex Figure Recall, and Craft Story 21 Delayed Recall. It had excellent performance in discriminating MCI/dementia from normal cognition (area under the receiver operating characteristic curve [AUROC] 90.0%, 95% confidence interval [CI] 89.2%-90.7%), which was comparable to that of the FNB (AUROC 88.4%, 95% CI 87.6%-89.2%). By contrast, MoCA alone had significantly worse AUROC (86.9%, 95% CI 86.0%-87.7%) than that of the FNB.Conclusions/ImplicationsUsing rigorous methods, this study developed a brief neuropsychological battery that maintained the brevity of a bedside cognitive test, while rivaling the diagnostic performance of an FNB in early cognitive impairment. This brief battery offers a viable alternative when the FNB is needed but cannot be feasibly administered in nonspecialty clinics. It can have a wider health systems effect of improving patients’ access to accurate diagnosis in early cognitive impairment and facilitating timely interventions to delay the progression of cognitive impairment.  相似文献   
56.
自身免疫性肝炎的肝组织病理学可表现各异,界面性肝炎伴淋巴-浆细胞浸润、“玫瑰花环”样结构及穿入现象是相对特征性表现,但非特异性。以上组织学表现需结合临床资料排除其他原因引起的肝炎才能诊断。主要阐述了自身免疫性肝炎的特征性组织学表现和特殊类型自身免疫性肝炎的组织学表现,讨论了组织学在自身免疫性肝炎的诊断与鉴别诊断中的价值。  相似文献   
57.
《Journal of endodontics》2020,46(6):786-793
IntroductionThis case-control study aimed to compare trigeminal somatosensory sensitivity between patients with a clinical diagnosis of symptomatic irreversible pulpitis (n = 33) and healthy participants (n = 33) and to evaluate the impact of somatosensory stratification of symptomatic irreversible pulpitis on pulp sensibility testing.MethodsA standardized battery of qualitative sensory assessment measured intra- and extraoral sensitivity to touch, cold, and pinprick stimuli. Dental pain intensity (0–100, numeric rating scale) and duration (seconds) evoked by cold stimuli (refrigerant spray) were applied to, respectively, the nonaffected and affected tooth (cases) and the upper right and left premolars (controls); z score transformation, analysis of variance (ANOVA), and chi-square tests were applied to the data (P = .050).ResultsPatients with irreversible pulpitis reported intraoral hypersensitivity more frequently than healthy participants (58% and 33%, respectively; P < .05). In addition, patients with irreversible pulpitis reported higher z scores of pain intensity (ANOVA main effects, F = 37.10, P < .05, partial η2 = 0.37) and duration (ANOVA main effects F = 23.3, P < .05, partial η2 = 0.27) after the pulp sensibility test compared with healthy participants. Nevertheless, subgroup analysis taking into account the presence of intraoral hypersensitivity indicated that the pain lingered most for patients with symptomatic irreversible pulpitis who also presented intraoral hypersensitivity (Tukey test, P < .05) but with no differences between patients with irreversible pulpitis without intraoral hypersensitivity and healthy participants (Tukey test, P > .05).ConclusionsQualST is able to detect intraoral alterations in patients with symptomatic irreversible pulpitis that seem useful to stratify the patients into distinct subgroups. Therefore, somatosensory assessment of the adjacent tissues may provide diagnostic fine-tuning of dental pulp diseases.  相似文献   
58.
目的对中国汉族肢带型肌营养不良2D(limb-girdle muscular dystrophy type 2D,LGMD2D)型的2个家系进行SGCA基因分析,明确病因并在此基础上为该家系中的胎儿进行产前诊断,提供遗传咨询与指导。方法回顾性收集2017年6月至2018年1月在郑州大学第一附属医院就诊的2个LGMD2D型家系,提取先证者和其父母的外周血,通过探针杂交技术对先证者LGMD相关21个基因编码区及其侧翼序列进行高通量测序,进一步采用Sanger测序和/或荧光定量聚合酶链反应对先证者父母目标基因区域进行检测,同时验证变异来源;明确先证者病因后,进一步对家系中胎儿进行产前诊断。结果家系1:先证者存在SGCA基因c.218C>G(p.P73R)和c.101G>A(p.R34H)复合杂合变异;产前诊断结果显示,胎儿与先证者一样同时遗传了父母双方的致病变异,胎儿父母选择终止妊娠。家系2:先证者携带SGCA基因c.218C>T(p.P73L)和该基因第7和第8外显子杂合缺失复合杂合变异,但胎儿不携带上述两变异,家属选择继续妊娠。胎儿足月分娩,随访至2岁,肌酶谱、体格、运动和智力发育均未见异常。结论SGCA基因复合杂合突变是2个LGMD2D型家系的致病原因,其中c.218C>G(p.P73R)、c.218C>T(p.P73L)为尚未报道的新突变。基于高通量测序可快速、准确地对该病进行基因诊断和产前诊断。  相似文献   
59.
        80%的女性一生中都可能会感染人乳头瘤病毒(HPV),其中大多数是一过性的感染,能被自身的免疫系统所清除。高危型 HPV持续感染是子宫颈鳞状上皮内病变的主要原因。近年来,随着筛查的普及、生活水平的提高、诊断技术的提高等,多数子宫颈鳞状上皮内病变能够得到早期诊断和及时治疗。然而,由于对高危型HPV感染和子宫颈鳞状上皮内病变诊断和治疗适应证掌握不严格,出现了不必要的筛查和不必要的阴道镜活检等过度诊断,对不需治疗的患者实施了治疗、简单治疗复杂化等过度治疗现象。本文针对高危型HPV感染和子宫颈鳞状上皮内病变的过度诊治问题进行讨论。 浏览更多请关注本刊微信公众号及当期杂志。  相似文献   
60.
        随着社会的发展,人们对美的追求越来越高,小阴唇整形也逐渐受到人们的关注。尽管小阴唇整形术方法有很多,但手术指征、手术方式选择、围术期管理及术后并发症防治等缺乏统一的标准[1-2]。中国整形美容协会女性生殖整复分会组织专家,根据文献报道[3]和专家经验,经过反复的讨论和修改,对小阴唇整形术提出如下共识,以期为临床医生对小阴唇肥大的诊治及整形决策提供参考及借鉴。 浏览更多请关注本刊微信公众号及当期杂志。  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