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   109974篇
  免费   8413篇
  国内免费   436篇
耳鼻咽喉   1006篇
儿科学   3496篇
妇产科学   2821篇
基础医学   14503篇
口腔科学   2509篇
临床医学   12830篇
内科学   23424篇
皮肤病学   1699篇
神经病学   9811篇
特种医学   2961篇
外国民族医学   2篇
外科学   13790篇
综合类   1414篇
现状与发展   1篇
一般理论   165篇
预防医学   10976篇
眼科学   2536篇
药学   7049篇
  5篇
中国医学   194篇
肿瘤学   7631篇
  2023年   768篇
  2022年   1071篇
  2021年   2459篇
  2020年   1728篇
  2019年   2396篇
  2018年   2757篇
  2017年   2033篇
  2016年   2285篇
  2015年   2525篇
  2014年   3535篇
  2013年   5374篇
  2012年   7382篇
  2011年   7834篇
  2010年   4384篇
  2009年   3996篇
  2008年   7007篇
  2007年   7284篇
  2006年   7051篇
  2005年   6969篇
  2004年   6600篇
  2003年   5986篇
  2002年   5698篇
  2001年   1088篇
  2000年   878篇
  1999年   1031篇
  1998年   1258篇
  1997年   996篇
  1996年   833篇
  1995年   825篇
  1994年   729篇
  1993年   703篇
  1992年   714篇
  1991年   667篇
  1990年   558篇
  1989年   549篇
  1988年   518篇
  1987年   457篇
  1986年   448篇
  1985年   514篇
  1984年   530篇
  1983年   494篇
  1982年   653篇
  1981年   566篇
  1980年   587篇
  1979年   363篇
  1978年   385篇
  1977年   370篇
  1976年   306篇
  1975年   320篇
  1974年   279篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.

Objectives

Post-thoracotomy pain leads to patient discomfort, pulmonary complications, and increased analgesic use. Intercostal nerve injury during thoracotomy or its entrapment during closure can contribute to post-thoracotomy pain. We hypothesized that a modified technique of posterolateral thoracotomy and closure, preserving the intercostal neurovascular bundle, would reduce acute and chronic post-thoracotomy pain.

Methods

We randomized 90 patients undergoing posterolateral thoracotomy for pulmonary resection at a tertiary level oncology center to standard posterolateral (control arm) or modified nerve-sparing thoracotomy. All patients received morphine via patient-controlled analgesia pumps. The primary outcome was the worst postoperative pain score in the first 3 postoperative days. Secondary outcomes included the average pain score and analgesic requirements in the first 3 postoperative days and the incidence of post-thoracotomy pain 6 months after surgery.

Results

No significant differences were seen between the groups in acute or chronic post-thoracotomy measured by the numeric rating scale. There was no difference seen in the worst (mean) postoperative pain scores (3.71 vs 3.83, difference 0.12; 99% confidence interval [CI], ?0.7 to +0.9; P = .7), average (mean) pain scores in the first 3 postoperative days (1.77 vs 1.85, difference 0.08; 99% CI, ?0.4 to +0.6; P = .69), mean consumption of morphine (mg/kg) (1.45 vs 1.40, difference ?0.05; 99% CI, ?0.4 to +0.3; P = .73), or incidence of chronic postoperative pain (37.8% vs 40%, difference 4.9%; 99% CI, ?22.8 to +30.7%; P = .73).

Conclusions

The modified nerve-sparing thoracotomy technique does not reduce post-thoracotomy pain compared with standard posterolateral thoracotomy.  相似文献   
2.

Objectives

To analyze the factors associated with fatigue focusing on comorbidities in a large cohort of rheumatoid arthritis (RA).

Methods

Cross-sectional analyses were performed on RA patients from the French COMEDRA cohort study, a nurse-led program for comorbidities management. Fatigue was assessed using Question 3 of the Rheumatoid Arthritis Impact of Disease (RAID) score on a 0–10 numerical rating scale (NRS). Fatigue was defined as acceptable if?≤?2, moderate if 3 or 4, or severe if?≥?5 out of 10. Using univariate and multivariate models, the relationship between fatigue and demographics, social, disease characteristics, comorbidities (cardiovascular, infections, cancer, pulmonary, osteoporosis, and psychiatric disorders), physical activity, quality of life, and treatments was investigated.

Results

In total, 962 patients were analyzed. The mean fatigue score was 3.8?±?2.7, 40% of patients reported severe fatigue. Patients had an average of 1.8 additional morbid conditions, with anxiety/depression the most common (52%). In univariate analysis, severe fatigue was more frequent in women, in patients not working, and in those with less physical activity. It was associated with disease duration and activity, mHAQ, pain, sleeping and emotional difficulties. Severe fatigue correlated with Multimorbidity index assessing the number of morbid conditions and was associated with obesity, hypertension, COPD, and anxiety/depression. In multivariate models, the risk of severe fatigue was associated with female gender, disease activity, mHAQ, current treatment with NSAIDs and biologics, multimorbidity, obesity and anxiety/depression.

Conclusions

Assessment of comorbidities, psychological health and physical activity should be taken into account in order to address frequent RA-related severe fatigue.  相似文献   
3.

Background and purpose

Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor.

Materials and methods

Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n?=?49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n?=?29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA).

Results

Motor group: paretic patients showed significantly (P?=?0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P?<?0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r?=?0.68, P?<?0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P?=?0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r?=?0.72, P?<?0.01) between BA 44 BOLD signal and phonological fluency performance was observed.

Conclusions

Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients.  相似文献   
4.
5.
6.
7.

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   
8.
This article describes a twinning relationship between the Canadian Association of Midwives (CAM) and the Tanzania Midwives Association (TAMA). It argues that the twinning relationship strengthened both associations. The article briefly reviews the existing literature on professional associations and association strengthening to demonstrate that professional associations are a vital tool for improving the performance of healthcare workers and increasing their capacity to contribute to national and international policy-making. It then suggests that midwifery associations are particularly significant given the frequent professional marginalization of midwives. The article then describes in depth the relationship between CAM and TAMA, highlighting the accomplishments of the twinned partners, and analyzing the factors that contributed to the success of the relationship. The findings demonstrate that twinning can successfully strengthen associations, increasing their ability to support their membership, care for the public, and shape national policy-making. The article therefore proposes twinning as a successful and cost-effective model for encouraging the growth of the midwifery profession.  相似文献   
9.
Increased functional brain response towards alcohol-associated stimuli is a neural hallmark of alcohol dependence and a promising target for pharmacotherapy. For the first time, we assessed the effects of individually titrated high-dose baclofen on cue reactivity and functional connectivity in alcohol-dependent (AD) patients in a randomized controlled trial (RCT).We investigated 23 recently detoxified AD patients and 23 matched healthy controls (HC) with a cue reactivity functional magnetic resonance imaging task. Patients were further scanned at baseline without medication and during treatment with high-dose baclofen/placebo (30–270 mg/d). Analyses were conducted for alcohol cue-elicited brain response, alcohol cue-modulated and stimulus-independent functional connectivity with left ventral tegmental area (VTA) as seed region.At baseline, AD patients (N?=?23) showed increased cue-elicited brain activation in the ventral striatum (VS) compared to HC (N?=?23), which was decreased at the second scanning session compared to baseline. Patients receiving baclofen (N?=?10) showed a significant stronger decrease in cue-elicited brain activation in left orbitofrontal cortex (OFC), bilateral amygdala and left VTA than patients receiving placebo (N?=?13). Treatment with baclofen further led to a decrease in alcohol cue-modulated functional connectivity between left VTA and left anterior cingulate cortex (ACC) as well as left medial prefrontal cortex (MPFC). Regarding clinical outcome, significantly more patients of the baclofen group remained abstinent during the high-dose period.Baclofen specifically decreased cue-elicited brain responses in areas known to be involved in the processing of salient (appetitive and aversive) stimuli. Treatment with high-dose baclofen seems to provide a pharmacological relief of this neural “warning signal” evoked by alcohol-related cues, thereby possibly supporting patients in remaining abstinent.Trial Registration Identifier of the main trial [BACLAD study] at clinicaltrials.gov: NCT01266655.  相似文献   
10.
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