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   2500689篇
  免费   221624篇
  国内免费   6127篇
耳鼻咽喉   38435篇
儿科学   77453篇
妇产科学   64992篇
基础医学   337674篇
口腔科学   68968篇
临床医学   238453篇
内科学   507600篇
皮肤病学   54760篇
神经病学   213140篇
特种医学   101097篇
外国民族医学   891篇
外科学   394287篇
综合类   56478篇
现状与发展   73篇
一般理论   978篇
预防医学   196697篇
眼科学   58431篇
药学   178398篇
  4篇
中国医学   4378篇
肿瘤学   135253篇
  2018年   30307篇
  2017年   24895篇
  2016年   27476篇
  2015年   30260篇
  2014年   46532篇
  2013年   63946篇
  2012年   73258篇
  2011年   76888篇
  2010年   51206篇
  2009年   52846篇
  2008年   73628篇
  2007年   76580篇
  2006年   79582篇
  2005年   75248篇
  2004年   71969篇
  2003年   68777篇
  2002年   68012篇
  2001年   115672篇
  2000年   119094篇
  1999年   101023篇
  1998年   30861篇
  1997年   28315篇
  1996年   28054篇
  1995年   27161篇
  1994年   24698篇
  1993年   22768篇
  1992年   80468篇
  1991年   77501篇
  1990年   74433篇
  1989年   71794篇
  1988年   66679篇
  1987年   65504篇
  1986年   62063篇
  1985年   59017篇
  1984年   44676篇
  1983年   38070篇
  1982年   23279篇
  1981年   20683篇
  1980年   19351篇
  1979年   41543篇
  1978年   29273篇
  1977年   24703篇
  1976年   23047篇
  1975年   24192篇
  1974年   29816篇
  1973年   28230篇
  1972年   26484篇
  1971年   24320篇
  1970年   22953篇
  1969年   21171篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Optimizing glycemic control remains a shared challenge for clinicians and their patients with diabetes. Flash continuous glucose monitoring (CGM) provides immediate information about an individual’s current and projected glucose level, allowing users to respond promptly to mitigate or prevent pending hypoglycemia or hyperglycemia. Large randomized controlled trials (RCTs) have demonstrated the glycemic benefits of flash CGM use in both type 1 and type 2 diabetes. However, whereas RCTs are mostly focused on the efficacy of this technology in defined circumstances, real-world studies can assess its effectiveness in wider clinical settings. This review assesses the most recent real-world studies demonstrating the effectiveness of flash CGM use to improve clinical outcomes and health care resource utilization in populations with diabetes.

During the past 5 years, increasing numbers of people with type 1 or type 2 diabetes have integrated continuous glucose monitoring (CGM) into their diabetes self-management regimens. Unlike traditional blood glucose meters, CGM systems provide immediate information about the concentration and the direction and rate of change of interstitial glucose. This information enables patients to intervene promptly to prevent or reduce acute hypoglycemia or hyperglycemia.Flash CGM is among the most recent CGM technologies. Currently, the FreeStyle Libre 14-day system (Abbott Diabetes Care) and FreeStyle Libre 2 are the only flash CGM systems available, and these systems are being adopted rapidly. Large randomized controlled trials (RCTs) have confirmed the glycemic benefits of flash CGM use in people with type 1 diabetes (1,2) and those with type 2 diabetes (36). However, because RCTs are mostly focused on measures of efficacy in defined circumstances, real-world studies can usefully assess the effectiveness of flash CGM in wider clinical settings.Although adoption of flash CGM continues to expand within endocrinology and diabetes specialty practices, primary care providers may be less familiar with this technology and how it can benefit patients with diabetes. This review assesses recent real-world studies demonstrating the impact of flash CGM use on clinical outcomes and health care resource utilization in both type 1 and type 2 diabetes populations.  相似文献   
22.
AimsSelf-expanding metal stents provide rapid improvement of dysphagia in oesophageal cancer but are associated with complications. The aim of the present study was to test the effectiveness of an alternative treatment of combining biodegradable stents with radiotherapy.Materials and methodsA Simon two-stage single-arm prospective phase II trial design was used to determine the efficacy of biodegradable stents plus radiotherapy in patients with dysphagia caused by oesophagus cancer who were unsuitable for radical treatment. Fourteen patients were recruited and data from 12 were included in the final analyses.ResultsFive of 12 patients met the primary end point: one stent-related patient death; four further interventions for dysphagia within 16 weeks of stenting (41.7%, 95% confidence interval 15.2–72.3%). The median time to a 10-point deterioration of quality of life was 2.7 weeks. Nine patients died within 52 weeks of registration. The median time to death from any cause was 15.0 weeks (95% confidence interval 9.6–not reached).ConclusionThe high re-intervention observed, which met the pre-defined early stopping criteria, meant that the suggested alternative treatment was not sufficiently effective to be considered for a larger scale trial design. Further work is needed to define the place of biodegradable stents in the management of malignant oesophageal strictures.  相似文献   
23.
ABSTRACT

Expeditious linkage and consistent engagement in medical care is important for people with HIV’s (PWH) health. One theory on fostering linkage and engagement involves HIV status disclosure to mobilize social support. To assess disclosure and social support’s association with linkage and engagement, we conducted a qualitative study sampling black and Latino men who have sex with men (MSM of color) in the U.S. Participants' narratives presented mixed results. For instance, several participants who reported delaying, inconsistent access, or detachment from care also reported disclosing for support purposes, yet sporadic engagement suggests that their disclosure or any subsequent social support have not assisted. The findings contribute to the literature that questions disclosure and social support’s influence on care engagement, especially when decontextualized from circumstances and intentions. Our findings suggest the mechanics of disclosure and social support require planned implementation if intending to affect outcomes, especially among MSM of color. From the findings, we explore steps that may bolster interventions seeking to anchor medical care engagement.  相似文献   
24.

Background

Nursing Home Compare (NHC) ratings, created and maintained by Medicare, are used by both hospitals and consumers to aid in the skilled nursing facility (SNF) selection process. To date, no studies have linked NHC ratings to actual episode-based outcomes. The purpose of this study was to evaluate whether NHC ratings are valid predictors of 90-day complications, readmission, and bundle costs for patients discharged to an SNF after primary total joint arthroplasty (TJA).

Methods

All SNF-discharged primary TJA cases in 2017 at a multihospital academic health system were queried. Demographic, psychosocial, and clinical variables were manually extracted from the health record. Medicare NHC ratings were then collected for each SNF. For patients in the Medicare bundle, postacute and total bundle cost was extracted from claims.

Results

Four hundred eighty-eight patients were discharged to a total of 105 unique SNFs. In multivariate analysis, overall NHC rating was not predictive of 90-day readmission/major complications, >75th percentile postacute cost, or 90-day bundle cost exceeding the target price. SNF health inspection and quality measure ratings were also not predictive of 90-day readmission/major complications or bundle performance. A higher SNF staffing rating was independently associated with a decreased odds for >75th percentile 90-day postacute spend (odds ratio, 0.58; P = .01) and a 90-day bundle cost exceeding the target price (odds ratio = 0.69; P = .02) but was similarly not predictive of 90-day readmission/complications.

Conclusion

Results of our study suggest that Medicare's NHC tool is not a useful predictor of 90-day costs, complications, or readmissions for SNFs within our health system.  相似文献   
25.

Objective

The frailty index has been linked to adverse outcomes after surgical procedures. In this study, we evaluated the association between frailty index and outcomes after elective lower extremity bypass (LEB) for lower extremity ischemia.

Methods

The American College of Surgeons National Surgical Quality Improvement Program data set (2005-2012) was used to identify patients who underwent elective LEB using diagnostic and procedure Current Procedural Terminology codes. Modified frailty index (mFI) scores, derived from the Canadian Study of Health and Aging, were categorized into three groups: low, medium, and high. Association of mFI with 30-day postoperative death (POD), myocardial infarction (MI), cardiopulmonary events (CPEs), deep tissue surgical site infection (SSI), and graft failure (GF) was evaluated. Both univariate and multivariable regression analyses—adjusted for age, sex, American Society of Anesthesiologists class, body mass index, and creatinine levels—were used to assess the effect of frailty on each outcome.

Results

Of 12,677 patients (mean age, 67.7 ± 11.1 years) identified who underwent elective LEB, POD occurred in 265 (2.1% overall). Postoperative MI, SSI, CPEs, and GF occurred in 1.6%, 2.5%, 3.1%, and 4.3%, respectively. The mean mFI of the entire sample was 0.3 ± 0.1. Adjusted odds ratio for development of any morbidity in the group with the highest mFI was 1.36 (95% confidence interval, 1.08-1.72; P = .010) compared with the low frailty group. Patients with higher mFI were more likely to develop MI and CPEs but not SSI or GF. Univariate and multivariable analyses showed a significantly increased risk of POD among those in the highest mFI tertile. Female sex and age, increased American Society of Anesthesiologists class and creatinine levels, and decreased body mass index independently predicted increased mortality. The addition of categorical mFI improved models with these variables.

Conclusions

Higher mFI is independently associated with higher mortality and morbidity. Preoperative mFI assessment may be considered an additional screening tool for risk stratification among patients undergoing LEB.  相似文献   
26.

Background and aims

There is controversy on the potentially benign nature of metabolically healthy obesity (MHO), i.e., obese persons with few or no metabolic abnormalities. So far, associations between MHO and coronary artery calcification (CAC), a measure of subclinical atherosclerosis, have mainly been studied cross-sectionally in Asian populations. We assessed cross-sectional and longitudinal MHO CAC associations in a Caucasian population.

Methods and results

In the Heinz Nixdorf Recall Study, a population-based cohort study in Germany, CAC was assessed by electron-beam tomography at baseline and at 5-year follow-up. For cross-sectional and longitudinal analyses, we included 1585 participants free of coronary heart disease at baseline, with CAC measurements at baseline and at follow-up, and with either normal weight (BMI 18.5–24.9 kg/m2) or obesity (BMI ≥30.0 kg/m2) at baseline. We used four definitions of MHO. In our main analysis, we defined obese persons as metabolically healthy if they met ≤1 of the NCEP ATP III criteria for the definition of the metabolic syndrome – waist circumference was not taken into account because of collinearity with BMI.Persons with MHO had a higher prevalence of CAC than metabolically healthy normal weight (MHNW) persons (prevalence ratio = 1.59 (95% confidence interval 1.38–1.84) for the main analysis). Persons with MHO had slightly larger odds of CAC progression than persons with MHNW (odds ratios ranged from 1.17 (0.69–1.99) to 1.48 (1.02–2.13) depending on MHO definition and statistical approach).

Conclusion

Our analyses on MHO CAC associations add to the evidence that MHO is not a purely benign health condition.  相似文献   
27.

Objective

To compare perioperative and long-term outcomes in patients undergoing hemiarch and aggressive arch replacement for acute type A aortic dissection (ATAAD).

Methods

From 1996 to 2017, we compared outcomes of hemiarch (n = 322) versus aggressive arch replacements (zones 2 and 3 arch replacement with implantation of 2-4 arch branches, n = 150) in ATAAD. Indications for aggressive arch were arch aneurysm >4 cm or intimal tear in the aortic arch that was not resectable by hemiarch replacement, or dissection of arch branches with malperfusion.

Results

Patients in the aggressive arch group were significantly younger (mean age: 57 vs 61 years old) and had significantly longer hypothermic circulatory arrest, cardiopulmonary bypass, and aortic crossclamp times. There were no significant differences in perioperative outcomes between hemiarch and aggressive arch groups, including 30-day mortality (5.3% vs 7.3%, P = .38) and postoperative stroke rate (7% vs 7%, P = .96). Over 15 years, Kaplan–Meier survival was similar between hemiarch and aggressive arch groups (log-rank P = .55, 10-year survival 70% vs 72%). Given death as a competing factor, incidence rates of reoperation over 15 years (2.1% vs 2.0% per year, P = 1) and 10-year cumulative incidence of reoperation (14% vs 12%, P = .89) for arch and distal aorta pathology were similar between the 2 groups.

Conclusions

Both hemiarch and aggressive arch replacement are appropriate approaches for select patients with ATAAD. Aggressive arch replacement should be considered for an arch aneurysm >4 cm or an intimal tear at the arch unable to be resected by hemiarch replacement, or dissection of the arch branches with malperfusion.  相似文献   
28.

Context

Quality of life (QoL) is increasingly recognized as an important outcome of cancer treatment. Previous studies have examined clinical predictors of QoL, but with the increasing prevalence of wearable sensors that monitor sleep and activity patterns, further investigation into whether these behaviors are predictive of post-treatment QoL is now feasible. Among patients receiving aggressive cancer treatment such as hematopoietic cell transplantation (HCT), analysis of circadian rhythms (24-hour patterns of sleep and activity) via wearable sensors is limited.

Objective

To evaluate the relationship between overall QoL and circadian rhythms in patients receiving allogeneic HCT.

Methods

Patients wore an ActiGraph GT3X (Pensacola, FL) activity monitor for at least 72 hours before the initiation of conditioning chemotherapy and transplantation and completed a QoL (Functional Assessment of Cancer Therapy-General [FACT-G]) assessment. QoL assessments were also completed 1, 3, and 6 months after HCT.

Results

Patients (n = 45, M age = 55) were mostly male (66%) with a total FACT-G score of 80.96 (SD = 16.05) before HCT. Mixed models revealed robust cross-sectional associations between overall QoL and multiple circadian rhythmicity parameters, including durations of high physical activity, overall circadian rhythmicity, and earlier starts of daily activity (P's < .01). Recovery of QoL after transplant was predicted by longer pre-transplant durations of high physical activity (P = .04) and earlier evening retirement (P = .04).

Conclusion

Our findings suggest that wearable sensor information is a promising method of predicting recovery of QoL after HCT. Additional studies are needed to confirm these findings in a larger sample.  相似文献   
29.

Background

Pulmonary hypertension (PH) is a comorbidity associated with interstitial lung disease (ILD). The purpose of this study was to evaluate the influence of PH on intrahospital mortality in lung transplantation (LT) for ILD.

Methods

We conducted a retrospective cohort study of 66 patients who underwent LT for ILD at the 12 de Octubre University Hospital (Madrid, Spain) from October 2008 to June 2014. PH was defined as mean pulmonary arterial pressure (mPAP) ≥25 mmHg on right-sided heart catheterization and intrahospital mortality as any death taken place after the transplantation of patients not being discharged.

Results

We retrospectively analyzed data of 66 patients; they were stratified by the presence or absence of PH before LT. Twenty-seven patients (41%) had PH. The PH group had a lower diffusing capacity of carbon monoxide (DLCO), carbon monoxide transfer coefficient (KCO), and 6-minute walk distance test (6MWT) and a higher total lung capacity (TLC), modified medical research council dyspnea scale (mMRC), and lung allocation score (LAS) than the non-PH group. Patients with PH more often underwent double lung transplantation (DLT; 59%) than single lung transplantation (SLT).Intrahospital mortality was 13% (9/66). No significant differences were observed in Kaplan-Meier survival curves for the PH and non-PH groups with a median survival time of 46 days versus 33 days (IQR 26–74; log-rank P = .056); however, the postoperative length of stay in the hospital was greater in the PH group.

Conclusions

In our cohort, pulmonary hypertension was not related to early mortality in lung transplantation recipients for interstitial lung diseases.  相似文献   
30.

Background

Life expectancy of people with severe mental illness (SMI) is greatly shortened compared to the general population, and despite extensive research, this issue is unsolved. Although it is widely recognised that people with SMI need support from health care services to manage health related issues, profound health inequalities exist within provision of health care. The aim of this study was to examine how mental health care professionals accounted for their actions and responsibilities related to managing physical health issues among people with SMI.

Methods

Three focus groups were conducted with 22 mental health care professionals, employed at three mental health care locations. Participants' situated accounts were subjected to discourse analysis.

Results

Participants accounted for actions and responsibilities in three typical ways; 1) by positioning people with SMI as difficult to motivate and actively resisting intervention, 2) by positioning people with SMI as so impaired that intervention was futile, and 3) by arguing they are undertreated for physical conditions and might have physical illnesses that staff are not aware of because of prominent mental illness. These discursive strategies seemed to legitimise situations where participants described not responding to physical health issues, and to downplay potential trouble in situations where participants described not succeeding in facilitating lifestyle changes or promoting compliance to treatment of physical conditions.

Discussion and conclusion

Mental health care professionals need to increase their awareness of latent discriminating attitudes towards people with SMI. Such attitudes are suggested to reinforce barriers for people with SMI receiving physical health care.  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