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   161676篇
  免费   6998篇
  国内免费   545篇
耳鼻咽喉   2652篇
儿科学   4716篇
妇产科学   3647篇
基础医学   21693篇
口腔科学   5677篇
临床医学   10469篇
内科学   39335篇
皮肤病学   5098篇
神经病学   13084篇
特种医学   3805篇
外国民族医学   2篇
外科学   19876篇
综合类   967篇
一般理论   46篇
预防医学   15679篇
眼科学   3403篇
药学   11339篇
中国医学   906篇
肿瘤学   6825篇
  2023年   1017篇
  2022年   1729篇
  2021年   4282篇
  2020年   2157篇
  2019年   4089篇
  2018年   5826篇
  2017年   3454篇
  2016年   3348篇
  2015年   3755篇
  2014年   5076篇
  2013年   7267篇
  2012年   11332篇
  2011年   12206篇
  2010年   6424篇
  2009年   5038篇
  2008年   9439篇
  2007年   10050篇
  2006年   9287篇
  2005年   9237篇
  2004年   8314篇
  2003年   7709篇
  2002年   7124篇
  2001年   4432篇
  2000年   5000篇
  1999年   3929篇
  1998年   908篇
  1997年   701篇
  1996年   580篇
  1995年   511篇
  1994年   411篇
  1993年   340篇
  1992年   1502篇
  1991年   1273篇
  1990年   1135篇
  1989年   937篇
  1988年   815篇
  1987年   746篇
  1986年   762篇
  1985年   658篇
  1984年   465篇
  1983年   392篇
  1979年   430篇
  1975年   299篇
  1974年   382篇
  1973年   386篇
  1972年   331篇
  1971年   357篇
  1970年   324篇
  1969年   345篇
  1968年   307篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.

Background

The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.

Methods

A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.

Results

Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.

Conclusions

In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler.  相似文献   
2.
Abstract

Objectives: This study examined word use as an indicator of interpersonal positive reframing in daily conversations of couples coping with breast cancer and as a predictor of stress.

Design: The Electronically Activated Recorder (EAR) and Linguistic Inquiry and Word Count (LIWC) were used to examine naturally occurring word use conceptually linked to positive reframing (positive emotion, negative emotion, and cognitive processing words).

Sample: Fifty-two couples coping with breast cancer.

Methods: Couples wore the EAR, a device participants wear, that audio-recorded over one weekend (>16,000 sound files), and completed self-reports of positive reframing (COPE) and stress (Perceived Stress Scale). LIWC, a software program, measured word use.

Findings: Both partners’ word use (i.e., positive emotion and cognitive processing words) was associated with their own reported positive reframing, and spouses’ word use was also indicative of patients’ positive reframing. Results also revealed that, in general, words indicating positive reframing predicted lower levels of stress.

Conclusions: Findings supported the hypothesis that partners—and particularly spouses of breast cancer patients—may assist each other’s coping by positively reframing the cancer experience and other negative experiences in conversation.  相似文献   
3.
4.
5.

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

Methods and results

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

Conclusion

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.  相似文献   
6.
ABSTRACT

This study closely examines 51 breast cancer narratives Latina and Spanish women wrote for other patients to illuminate how they conceptualize their health, with insights for addressing health disparities. Using discourse analysis of the role of language and culture in health care communication, this study focuses on the use of metaphors in the narratives. This provides revelations about the cultural and linguistic aspects of how the writers conceptualize their disease. Building on past research on metaphor use in cancer discourse in the English language, this study reveals the prevalence of metaphors comparing cancer to combat, or more generally, violence (e.g., “my battle against cancer”), or a journey (e.g., “my path with cancer”). Writers used this metaphorical language to offer advice to others with cancer and to mark their membership in a larger community of people with cancer. We also find that Spanish women use metaphors more frequently than Latinas and that they differed in their metaphorical portrayals of cancer. This research uncovers culturally embedded themes that are central to how women with cancer think about the disease, such as the prominence of spirituality in Latinas’ metaphorical constructions, a pattern not evident in Spanish women’s narratives.  相似文献   
7.
We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.  相似文献   
8.
9.
10.
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members.  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