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   3597546篇
  免费   253992篇
  国内免费   6489篇
耳鼻咽喉   49257篇
儿科学   116210篇
妇产科学   97494篇
基础医学   519343篇
口腔科学   104145篇
临床医学   323198篇
内科学   696136篇
皮肤病学   81100篇
神经病学   284802篇
特种医学   132488篇
外国民族医学   695篇
外科学   533808篇
综合类   76726篇
现状与发展   14篇
一般理论   1295篇
预防医学   285394篇
眼科学   86743篇
药学   266054篇
  81篇
中国医学   8094篇
肿瘤学   194950篇
  2021年   30111篇
  2019年   30743篇
  2018年   43909篇
  2017年   32553篇
  2016年   35919篇
  2015年   40484篇
  2014年   56176篇
  2013年   83933篇
  2012年   117843篇
  2011年   124905篇
  2010年   73506篇
  2009年   67699篇
  2008年   115119篇
  2007年   122691篇
  2006年   123384篇
  2005年   118999篇
  2004年   114065篇
  2003年   109033篇
  2002年   105191篇
  2001年   165470篇
  2000年   170115篇
  1999年   142492篇
  1998年   40344篇
  1997年   35179篇
  1996年   35372篇
  1995年   33511篇
  1994年   30799篇
  1993年   28775篇
  1992年   109476篇
  1991年   106380篇
  1990年   103100篇
  1989年   99393篇
  1988年   91218篇
  1987年   89252篇
  1986年   84013篇
  1985年   80406篇
  1984年   59707篇
  1983年   50876篇
  1982年   29689篇
  1979年   54572篇
  1978年   38417篇
  1977年   32336篇
  1976年   30682篇
  1975年   32692篇
  1974年   39675篇
  1973年   38093篇
  1972年   35556篇
  1971年   33500篇
  1970年   31084篇
  1969年   29459篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.

Context

Goals-of-care discussions are associated with improved end-of-life care for patients and therefore may be used as a process measure in quality improvement, research, and reimbursement programs.

Objectives

To examine three methods to assess occurrence of a goals-of-care discussion—patient report, clinician report, and documentation in the electronic health record (EHR)—at a clinic visit for seriously ill patients and determine whether each method is associated with patient-reported receipt of goal-concordant care.

Methods

We conducted a secondary analysis of a multicenter cluster-randomized trial, with 494 patients and 124 clinicians caring for them. Self-reported surveys collected from patients and clinicians two weeks after a clinic visit assessed occurrence of a goals-of-care discussion. Documentation of a goals-of-care discussion was abstracted from the EHR. Patient-reported receipt of goal-concordant care was assessed by survey two weeks after the visit.

Results

Fifty-two percent of patients reported occurrence of a goals-of-care discussion at the clinic visit; clinicians reported occurrence of a discussion at 66% of visits. EHR documentation occurred in 42% of visits (P < 0.001 for each compared with other two). Patients who reported occurrence of a goals-of-care discussion at the visit were more likely to report receipt of goal-concordant care than patients who reported no discussion (β 0.441, 95% CI 0.190–0.692; P = 0.001). Neither occurrence of a discussion by clinician report nor by EHR documentation was associated with goal-concordant care.

Conclusion

Different approaches to assess goals-of-care discussions give differing results, yet each may have advantages. Patient report is most likely to correlate with patient-reported receipt of goal-concordant care.  相似文献   
62.

Background

The International Agency for Research on Cancer (IARC) has recently classified glyphosate as a Group 2A ‘probably carcinogenic to humans’. Due to this carcinogenic classification and resulting international debate, there is an increased demand for studies evaluating human health effects from glyphosate exposures. There is currently limited information on human exposures to glyphosate and a paucity of data regarding glyphosate's biological half-life in humans.

Objective

This study aims to estimate the human half-life of glyphosate from human urine samples collected from amenity horticulture workers using glyphosate based pesticide products.

Methods

Full void urine spot samples were collected over a period of approximately 24?h for eight work tasks involving seven workers. The elimination time and estimation of the half-life of glyphosate using three different measurement metrics: the unadjusted glyphosate concentrations, creatinine corrected concentrations and by using Urinary Excretion Rates (UER) (μg L?1, μmol/mol creatinine and UER μg L?1) was calculated by summary and linear interpolation using regression analysis.

Results

This study estimates the human biological half-life of glyphosate as approximately 5 ½, 10 and 7 ¼ hours for unadjusted samples, creatinine corrected concentrations and by using UER (μg L?1, μmol/mol creatinine, UER μg L?1), respectively. The approximated glyphosate half-life calculations seem to have less variability when using the UER compared to the other measuring metrics.

Conclusion

This study provides new information on the elimination rate of glyphosate and an approximate biological half-life range for humans. This information can help optimise the design of sampling strategies, as well as assisting in the interpretation of results for human biomonitoring studies involving this active ingredient. The data could also contribute to the development or refinement of Physiologically Based PharmacoKinetic (PBPK) models for glyphosate.  相似文献   
63.
ABSTRACT

Each year, over 600 youth under the age of 25 experience literal homelessness in Austin, Texas. Of these youth, 76% have a history of involvement with foster care or the juvenile justice system—far exceeding the rates of system involvement observed among homeless youth in other large communities in the United States (approximately 54%; Voices of Youth Count, 2017). Recently, Austin was selected by the U.S. Department of Housing & Urban Development as one of ten communities nationwide to participate in the Youth Homelessness Demonstration Program (YHDP), a federal initiative designed to effectively end youth homelessness by 2020. Youth with lived experience are central players in the development and implementation of Austin's response to the youth homelessness crisis. A group of twelve of these youth (the “Austin Youth Collective to End Youth Homelessness,” or AYC) serve as key decision-making partners within the Austin YHDP team. Representatives of the AYC are deeply involved at every level of the community planning process, from the development of youth-centric housing options to system redesign efforts to ensure that youth do not exit the foster care or juvenile justice systems to homelessness. The article provides an overview of the development and contributions of the AYC—including their programmatic recommendations and advocacy work—as well as key recommendations for communities looking to leverage youth voice at the systems level.  相似文献   
64.

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   
65.

Objective

To assess a 6-month nutritional and physical activity intervention program on the nutritional status of overweight or obese and not very active 8-14 years old children by means of a controlled pre-post design (ACTIVA’T program).

Method

Pre-post study in 8-14 years old overweight or obese and low active children from Vilafranca del Penedès (Barcelona, Spain) randomized in control group (n = 51, 47.1% girls, nutritional intervention and ≤3 h/wk physical activity) and ACTIVA’T group (n = 45, 37.8% girls, nutritional and physical activity ≥5 h/wk intervention). Body mass index, waist/height index, and diet quality by means of KIDMED test at the beginning and at the end of the program were assessed. During the intervention, each participant was accompanied by a relative (father or mother) who performed the same activities as the children.

Results

Dietary recommendations have positively changed the habits of both ACTIVA’T and control group. The reversion in the prevalence of overweight and obesity was 93.8% and 58.6%, respectively, in the ACTIVA’T group, compared to 25.0% and 35.8% in the control group. Abdominal obesity was decreased from 42.2% to 17.8% in the ACTIVA’T group and from 47.1% to 27.5% in the control group.

Conclusions

The program ACTIVA’T (nutritional education and physical activity promotion) improves the quality of diet and reverses the prevalence of overweight and obesity in the underactive child population.  相似文献   
66.

Introduction

When evaluating a quality-of-life questionnaire (QLQ), many validation studies do not correlate quality-of-life scores with objective measurements of complications associated with treatment.

Patients and Methods

We performed a cross-sectional observational study with 300 patients submitted to breast-conserving therapy. The patients answered the European Organization for Research and Treatment of Cancer (EORTC) QLQs C-30 and BR23, as well as the Brazilian Portuguese version of the Breast Cancer Treatment Outcome Scale (BCTOS) questionnaire. Retest, internal consistency, factorial analysis, convergent/divergent analysis, and Rasch evaluation were performed. All patients underwent physical evaluations to assess lymphedema, handgrip strength, shoulder range of motion, breast cosmesis, and breast pain, and these groups were compared on the basis of BCTOS scores. Receiver operating characteristic curve determined the predictive value of BCTOS scores associated with clinical practice.

Results

The internal consistencies of the BCTOS domains ranged from 0.785 to 0.895. Factor analysis grouped according to the original questionnaire. Convergent validation showed differences in the sexual functioning and sexual enjoyment domains of the EORTC BR23. Analysis of known groups found that in most domains, the scores were higher in patients with lymphedema, strength deficit, shoulder range-of-motion alteration, poor breast cosmesis, breast pain, and axillary lymphadenectomy. Using a cutoff of 1.26, lymphedema was associated with the edema domain; using a cutoff of 1.33, Late Effects Normal Tissue Task Force/Subjective, Objective, Management, Analytic pain was associated with the pain domain; and using a cutoff of 2.37, the cosmetic domain was associated with subjective cosmesis.

Conclusion

The association of objective measurements in a validation study of quality of life qualified the study and allowed us to develop better parameters for comparisons of results of breast-conserving therapy between populations.  相似文献   
67.

Introduction

There are limited randomized data comparing radical cystectomy (RC) with bladder-sparing tri-modality therapy (TMT) in the treatment of muscle-invasive bladder cancer (MIBC). Both strategies are thought to have similar survival outcomes with different morbidity profiles. We compare the effectiveness of TMT and RC using decision-analytic modeling and the endpoint of quality-adjusted life years (QALYs).

Patients and Methods

Using a Markov model, we simulated the lifetime outcomes after TMT versus RC ± neoadjuvant chemotherapy for 67-year-old patients with clinical stage T2-T4aN0M0 MIBC. Model probabilities and utilities were extracted from the literature. The incremental effectiveness was reported in QALYs and sensitivity analyses were performed.

Results

For all patients with MIBC, although the model showed identical survival, TMT was the most effective strategy with an incremental gain of 0.59 QALYs over RC (7.83 vs. 7.24 QALYs, respectively). When limiting the model to favorable, contemporary cohorts in both the TMT and RC strategies, TMT remained more effective with an incremental gain of 1.61 QALYs (9.37 vs. 7.76 QALYs, respectively). One-way sensitivity analyses demonstrated the model was sensitive to the quality of life parameters (ie, the utilities) for RC and TMT. When testing the 95% confidence interval of the RC utility parameter the model demonstrated an incremental gain with TMT from ?0.54 to 4.23 QALYs. Probabilistic sensitivity analysis demonstrated that TMT was more effective than RC for 63% of model iterations.

Conclusions

This modeling study found that treatment of MIBC with organ-sparing TMT in appropriately-selected patients may result in a gain of QALYs relative to RC.  相似文献   
68.
69.
Background Many breast, cervical, and colorectal cancer screening programmes were disrupted due to the COVID-19 pandemic. This study aimed to estimate the effects of five restart strategies after the disruption on required screening capacity and cancer burden.Methods Microsimulation models simulated five restart strategies for breast, cervical, and colorectal cancer screening. The models estimated required screening capacity, cancer incidence, and cancer-specific mortality after a disruption of 6 months. The restart strategies varied in whether screens were caught up or not and, if so, immediately or delayed, and whether the upper age limit was increased.Results The disruption in screening programmes without catch-up of missed screens led to an increase of 2.0, 0.3, and 2.5 cancer deaths per 100 000 individuals in 10 years in breast, cervical, and colorectal cancer, respectively. Immediately catching-up missed screens minimised the impact of the disruption but required a surge in screening capacity. Delaying screening, but still offering all screening rounds gave the best balance between required capacity, incidence, and mortality.Conclusions Strategies with the smallest loss in health effects were also the most burdensome for the screening organisations. Which strategy is preferred depends on the organisation and available capacity in a country.Subject terms: Health policy, Population screening, Cancer screening, Cancer screening  相似文献   
70.
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