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   1601857篇
  免费   131525篇
  国内免费   2582篇
耳鼻咽喉   21646篇
儿科学   52931篇
妇产科学   46229篇
基础医学   227786篇
口腔科学   47218篇
临床医学   140917篇
内科学   314783篇
皮肤病学   34091篇
神经病学   130121篇
特种医学   64728篇
外国民族医学   474篇
外科学   243828篇
综合类   39712篇
现状与发展   3篇
一般理论   544篇
预防医学   122917篇
眼科学   36485篇
药学   121280篇
  3篇
中国医学   2976篇
肿瘤学   87292篇
  2018年   14771篇
  2016年   12900篇
  2015年   15030篇
  2014年   20655篇
  2013年   31356篇
  2012年   42564篇
  2011年   44775篇
  2010年   26352篇
  2009年   25308篇
  2008年   43012篇
  2007年   45265篇
  2006年   46066篇
  2005年   44691篇
  2004年   44106篇
  2003年   42187篇
  2002年   41300篇
  2001年   75690篇
  2000年   78329篇
  1999年   66388篇
  1998年   17733篇
  1997年   16334篇
  1996年   16314篇
  1995年   16020篇
  1994年   15070篇
  1993年   14217篇
  1992年   55427篇
  1991年   53775篇
  1990年   52562篇
  1989年   50832篇
  1988年   47221篇
  1987年   46560篇
  1986年   44284篇
  1985年   42845篇
  1984年   32033篇
  1983年   27566篇
  1982年   16144篇
  1981年   14436篇
  1980年   13564篇
  1979年   30462篇
  1978年   21065篇
  1977年   17765篇
  1976年   16694篇
  1975年   17574篇
  1974年   21486篇
  1973年   20672篇
  1972年   18853篇
  1971年   17770篇
  1970年   16289篇
  1969年   15268篇
  1968年   13949篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
2.
3.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
4.
5.
6.

Introduction

Physician communication impacts patient outcomes. However, communication skills, especially around difficult conversations, remain suboptimal, and there is no clear way to determine the validity of entrustment decisions. The aims of this study were to 1) describe the development of a simulation-based mastery learning (SBML) curriculum for breaking bad news (BBN) conversation skills and 2) set a defensible minimum passing standard (MPS) to ensure uniform skill acquisition among learners.

Innovation

An SBML BBN curriculum was developed for fourth-year medical students. An assessment tool was created to evaluate the acquisition of skills involved in a BBN conversation. Pilot testing was completed to confirm improvement in skill acquisition and set the MPS.

Outcomes

A BBN assessment tool containing a 15-item checklist and six scaled items was developed. Students' checklist performance improved significantly at post-test compared to baseline (mean 65.33%, SD = 12.09% vs mean 88.67%, SD = 9.45%, P < 0.001). Students were also significantly more likely to have at least a score of 4 (on a five-point scale) for the six scaled questions at post-test. The MPS was set at 80%, requiring a score of 12 items on the checklist and at least 4 of 5 for each scaled item. Using the MPS, 30% of students would require additional training after post-testing.

Comments

We developed a SBML curriculum with a comprehensive assessment of BBN skills and a defensible competency standard. Future efforts will expand the mastery model to larger cohorts and assess the impact of rigorous education on patient care outcomes.  相似文献   
7.

Aims

To examine the influence of pre-existing psychiatric disorder on the choice of treatment in patients with gynaecological cancer.

Materials and methods

The analyses were based on all patients who underwent surgical treatment for endometrial, ovarian or cervical cancer who were registered in the Danish Gynecological Cancer Database in the years 2007–2014 (3059 patients with ovarian cancer, 5100 patients with endometrial cancer and 1150 with cervical cancer). Logistic regression model and Cox regression model, adjusted for relevant confounders, were used to estimate the effect of pre-existing psychiatric disorder on the course of cancer treatment. Our outcomes were (i) presurgical oncological treatment, (ii) macroradical surgery for patients with ovarian cancer, (iii) radiation/chemotherapy within 30 days and 100 days after surgery and (iv) time from surgery to first oncological treatment.

Results

In the group of patients with ovarian cancer, more patients with a psychiatric disorder received macroradical surgery versus patients without a psychiatric disorder, corresponding to an adjusted odds ratio of 1.24 (95% confidence interval 0.62–2.41) and the chance for having oncological treatment within 100 days was odds ratio = 1.26 (95% confidence interval 0.77–2.10). As for patients with endometrial cancer, all outcome estimates were close to unity. The adjusted odds ratio for oncological treatment within 30 days after surgery in patients with cervical cancer with a history of psychiatric disorder was 0.20 (95% confidence interval 0.03–1.54).

Conclusions

We did not find any significant differences in the treatment of ovarian and endometrial cancer in patients with pre-existing psychiatric diagnoses. When it comes to oncological treatment, we suggest that increased attention should be paid to patients with cervical cancer having a pre-existing psychiatric diagnosis.  相似文献   
8.

Background

Total knee arthroplasty is a treatment option for debilitating arthritis. In the postoperative period, patients experience moderate to severe pain affecting the rehabilitation, hospital stay, and patient satisfaction. This study aims at utilizing current best evidence to determine whether adductor canal block (ACB) or periarticular injection (PAI) is a better modality for managing short-term postoperative pain and opioid consumption.

Methods

Embase, MEDLINE, HealthStar, Emcare, and PubMed were searched for randomized controlled trials from 1946 to August 2018, for literature addressing the comparison of ACB and PAI for pain management in the setting of total knee arthroplasty. A systematic review and meta-analysis were performed.

Results

Six studies were included in our meta-analysis. When examining the combined visual analog scale (VAS) pain values for each group, analysis demonstrated greater reduction in scores for the PAI group, and the difference was statistically significant (P = .001). When comparing the VAS scores of subgroups analyzed at specific periods in time, there was a trend toward lower VAS scores in subgroups analyzed at 24 hours and 48 hours postoperatively (at rest and at movement) in the PAI group. Overall opioid consumption was lower in the PAI group, with demonstrated statistical significance (P = .03). When comparing the postoperative subgroups, there was a trend toward decreased opioid use in the PAI group, with 13.25% less opioid use at 48 hours and 9.5% less opioid use at 24 hours.

Conclusion

PAI could significantly improve postoperative pain and opioid consumption when compared with ACB. Additional, high-quality studies are required to further address this topic.  相似文献   
9.

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Objectives

The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.

Methods

PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.

Results

Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).

Conclusions

In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550)  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