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   1216661篇
  免费   95973篇
  国内免费   17621篇
耳鼻咽喉   14862篇
儿科学   36619篇
妇产科学   31367篇
基础医学   171619篇
口腔科学   31361篇
临床医学   121229篇
内科学   226182篇
皮肤病学   25075篇
神经病学   91518篇
特种医学   46498篇
外国民族医学   443篇
外科学   171098篇
综合类   59153篇
现状与发展   55篇
一般理论   404篇
预防医学   90835篇
眼科学   29323篇
药学   94412篇
  262篇
中国医学   14672篇
肿瘤学   73268篇
  2022年   12359篇
  2021年   18660篇
  2020年   13541篇
  2019年   14840篇
  2018年   18474篇
  2017年   15269篇
  2016年   16000篇
  2015年   20708篇
  2014年   26777篇
  2013年   32507篇
  2012年   44646篇
  2011年   48391篇
  2010年   28835篇
  2009年   25441篇
  2008年   39614篇
  2007年   41213篇
  2006年   41901篇
  2005年   40742篇
  2004年   35708篇
  2003年   34199篇
  2002年   32162篇
  2001年   51443篇
  2000年   52993篇
  1999年   45651篇
  1998年   14607篇
  1997年   13510篇
  1996年   12913篇
  1995年   12345篇
  1994年   11195篇
  1993年   9817篇
  1992年   33992篇
  1991年   32929篇
  1990年   32196篇
  1989年   30879篇
  1988年   28101篇
  1987年   28135篇
  1986年   26095篇
  1985年   25082篇
  1984年   18707篇
  1983年   15727篇
  1982年   9415篇
  1979年   16980篇
  1978年   12258篇
  1977年   10353篇
  1976年   9779篇
  1975年   10224篇
  1974年   12363篇
  1973年   11885篇
  1972年   10928篇
  1971年   10142篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

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   
52.

Background

There are conflicting data regarding the relative effectiveness of renal sympathetic denervation (RSD) in patients with hypertension.

Objectives

The purpose of this study was to evaluate the blood pressure (BP) response after RSD in sham-controlled randomized trials.

Methods

Databases were searched through June 30, 2018. Randomized trials (RCTs) with ≥50 patients comparing catheter-based RSD with a sham control were included. The authors calculated summary treatment estimates as weighted mean differences (WMD) with 95% confidence intervals (CIs) using random-effects meta-analysis.

Results

The analysis included 977 patients from 6 trials. The reduction in 24-h ambulatory systolic blood pressure (ASBP) was significantly greater for patients treated with RSD than sham procedure (WMD ?3.65 mm Hg, 95% CI: ?5.33 to ?1.98; p < 0.001). Compared with sham, RSD was also associated with a significant decrease in daytime ASBP (WMD ?4.07 mm Hg, 95% CI: ?6.46 to ?1.68; p < 0.001), office systolic BP (WMD ?5.53 mm Hg, 95% CI: ?8.18 to ?2.87; p < 0.001), 24-h ambulatory diastolic BP (WMD ?1.71 mm Hg, 95% CI: ?3.06 to ?0.35; p = 0.01), daytime ambulatory diastolic BP (WMD ?1.57 mm Hg, 95% CI: ?2.73 to ?0.42; p = 0.008), and office diastolic BP (WMD ?3.37 mm Hg, 95% CI: ?4.86 to ?1.88; p < 0.001). Compared with first-generation trials, a significantly greater reduction in daytime ASBP was observed with RSD in second-generation trials (6.12 mm Hg vs. 2.14 mm Hg; p interaction = 0.04); however, this interaction was not significant for 24-h ASBP (4.85 mm Hg vs. 2.23 mm Hg; p interaction = 0.13).

Conclusions

RSD significantly reduced blood pressure compared with sham control. Results of this meta-analysis should inform the design of larger, pivotal trials to evaluate the long-term efficacy and safety of RSD in patients with hypertension.  相似文献   
53.
54.
目的探讨案例式立体教学法在腹部提压心肺复苏培训中的应用效果。 方法选取2018年在南方医科大学附属郑州人民医院进行全科医师规范化培训的60名学员为研究对象,根据学员工号,采用数字奇偶法将其分为实验组和对照组,每组30名。实验组学员采用案例式立体教学法,对照组学员采用传统教学方法,培训结束后采用考核和问卷调查的方法对教学效果进行评估分析。 结果实验组学员理论成绩为(89.83±5.33)分,对照组学员理论成绩为(86.17±6.52)分,差异有统计学意义(P<0.05)。实验组学员技能成绩为(84.17±5.43)分,对照组学员技能成绩为(78.50±5.44)分,差异有统计学意义(P<0.05)。问卷调查结果显示,案例式立体教学法在增强学习兴趣、提高思维能力、深化学习印象、增强思考主动性、强化理论与临床桥接方面的满意度均优于传统教学法,差异均有统计学意义(均P<0.05)。 结论案例式立体教学法应用于全科医师的腹部提压心肺复苏培训,有利于提高学员理论成绩和技能成绩,有利于提高思维能力、增强思考主动性、增加学习兴趣、深化学习印象和强化理论与临床桥接。  相似文献   
55.

Introduction

There is an urgent need for new anti-tuberculosis (TB) drugs and optimization of current TB treatment. Moxifloxacin and linezolid are valuable options for the treatment of drug-resistant TB; however, it is crucial to find a dose at which these drugs not only show high efficacy but also suppress the development of further drug resistance.

Methods

Activity of moxifloxacin and linezolid against Mycobacterium tuberculosis was studied in the hollow-fiber infection model system in log-phase growth under neutral pH and slow growth in an acidic environment. Doses that achieved maximum bacterial kill while suppressing the emergence of drug resistance were determined. Through Monte Carlo simulations the quantitative output of this in vitro study was bridged to the human patient population to inform optimal dosage regimens while accounting for clinical minimum inhibitory concentration (MIC) distributions.

Results and Discussion

Moxifloxacin activity was significantly decreased in an acidified environment. The loss of activity was compensated by accumulation of the drug in TB lung lesions; therefore, moderate efficacy can be expected. Moxifloxacin 800 mg/day is the dose that most likely leads to resistance suppression while exerting maximum bacterial kill. Linezolid demonstrated very good activity even at a reduced pH. Linezolid 900 mg once-daily (QD) is likely to achieve a maximum killing effect and prevent the emergence of drug resistance; 600 mg QD in a robust drug regimen may have similar potential.  相似文献   
56.

Purpose

The purpose of this study was to assess the potential of a deep learning model to discriminate between benign and malignant breast lesions using magnetic resonance imaging (MRI) and characterize different histological subtypes of breast lesions.

Materials and methods

We developed a deep learning model that simultaneously learns to detect lesions and characterize them. We created a lesion-characterization model based on a single two-dimensional T1-weighted fat suppressed MR image obtained after intravenous administration of a gadolinium chelate selected by radiologists. The data included 335 MR images from 335 patients, representing 17 different histological subtypes of breast lesions grouped into four categories (mammary gland, benign lesions, invasive ductal carcinoma and other malignant lesions). Algorithm performance was evaluated on an independent test set of 168 MR images using weighted sums of the area under the curve (AUC) scores.

Results

We obtained a cross-validation score of 0.817 weighted average receiver operating characteristic (ROC)-AUC on the training set computed as the mean of three-shuffle three-fold cross-validation. Our model reached a weighted mean AUC of 0.816 on the independent challenge test set.

Conclusion

This study shows good performance of a supervised-attention model with deep learning for breast MRI. This method should be validated on a larger and independent cohort.  相似文献   
57.
58.
Visceral fat loss in response to four‐cycle ergometer training regimens with explicit differences in exercise intensity and modality was compared. Fifty‐nine obese young women (body fat percentage ≥ 30%) were randomized to a 12‐week intervention consisting of either all‐out sprint interval training (SITall‐out, n = 11); supramaximal SIT (SIT120, 120% O2peak, n = 12); high‐intensity interval training (HIIT90, 90% O2peak, n = 12), moderate‐intensity continuous training (MICT, 60% O2peak, n = 11), or no training (CON, n = 13). The total work done per training session in SIT120, HIIT90, and MICT was confined to 200 kJ, while it was deliberately lower in SITall‐out. The abdominal visceral fat area (AVFA) was measured through computed tomography scans. The whole‐body and regional fat mass were assessed through dual‐energy X‐ray absorptiometry. Pre‐, post‐, and 3‐hour post‐exercise serum growth hormone (GH), and epinephrine (EPI) were measured during selected training sessions. Following the intervention, similar reductions in whole‐body and regional fat mass were found in all intervention groups, while the reductions in AVFA resulting from SITall‐out, SIT120, and HIIT90 (>15 cm2) were greater in comparison with MICT (<3.5 cm2, P < .05). The AVFA reductions among the SITs and HIIT groups were similar, and it was concomitant with the similar exercise‐induced releases of serum GH and EPI. CON variables were unchanged. These findings suggest that visceral fat loss induced by interval training at or above 90% O2peak appeared unresponsive to the change in training intensity. Nonetheless, SITall‐out is still the most time‐efficient strategy among the four exercise‐training regimes for controlling visceral obesity.  相似文献   
59.
以一日四时人体阴阳的变化,即在不同的时间里人体的生理功能活动和在病理情况下"夫百病者,多以旦慧昼安,夕加夜甚"(《灵枢·顺气一日分为四时》)来论述因时制宜的重要性.本文仅肤浅地分析因时制宜并提出一日四时的治疗用药原则,又介绍了阳气虚证和阴虚盗汗证的治疗经验,对临床工作具有实用价值.  相似文献   
60.
刘果  宋乃光 《北京中医药》2006,25(6):363-364
圣散子为中医抗疫之名方,不仅因为其卓著的疗效,更有赖于一代文豪苏东坡的大力推荐.然而此方在流传的过程中,却出现了不少问题,甚则"杀人无数".本为疗寒疫之方,而用之于热疫,其中的原因值得深思.  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