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   12861篇
  免费   1115篇
  国内免费   552篇
耳鼻咽喉   139篇
儿科学   160篇
妇产科学   181篇
基础医学   1679篇
口腔科学   358篇
临床医学   1166篇
内科学   1467篇
皮肤病学   104篇
神经病学   1323篇
特种医学   435篇
外科学   1109篇
综合类   1659篇
一般理论   1篇
预防医学   1875篇
眼科学   274篇
药学   1621篇
  3篇
中国医学   299篇
肿瘤学   675篇
  2024年   10篇
  2023年   187篇
  2022年   213篇
  2021年   430篇
  2020年   472篇
  2019年   491篇
  2018年   460篇
  2017年   520篇
  2016年   507篇
  2015年   522篇
  2014年   733篇
  2013年   1187篇
  2012年   626篇
  2011年   825篇
  2010年   624篇
  2009年   666篇
  2008年   706篇
  2007年   639篇
  2006年   576篇
  2005年   516篇
  2004年   428篇
  2003年   415篇
  2002年   338篇
  2001年   302篇
  2000年   237篇
  1999年   180篇
  1998年   174篇
  1997年   157篇
  1996年   88篇
  1995年   127篇
  1994年   111篇
  1993年   116篇
  1992年   112篇
  1991年   99篇
  1990年   103篇
  1989年   109篇
  1988年   80篇
  1987年   78篇
  1986年   54篇
  1985年   45篇
  1984年   50篇
  1983年   35篇
  1982年   37篇
  1981年   30篇
  1980年   31篇
  1979年   19篇
  1978年   18篇
  1977年   12篇
  1976年   10篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
This study aimed to clarify whether the pattern recognition involved in scoring proliferation fractions can be trained by abstract computerized images of virtual tissues. Twenty computer-generated images with randomly distributed blue or red dots were scored by 12 probands (all co-workers or collaborators of the Institute of Pathology, University of Bonn). Afterward, the probands underwent a training phase during which they received an immediate feedback on the actual rate of positivity after each image. Finally, the initial testing series was rescored. In a second round with 15 different probands, 20 Ki-67 immunohistochemistry images of tonsil tissue were scored, followed by the same training phase with computer-generated images, before the immunohistochemistry slides were scored again. Paired t-tests were used to compare the differences in mean rates pre- and post-training. Concerning computerized images, untrained probands scored the percentages of positive dots with a mean deviation from the true rates of 8.2%. Following training, the same testing series was scored significantly better with a mean deviation of 4.9% (mean improvement 3.3%, p < 0.001). Scoring real immunohistochemistry slides, the training with computerized images also improved correct estimations, albeit to a lesser degree (mean improvement 1%, p = 0.03). Abstract computerized images of virtual tissues may be a useful tool to train and improve the accuracy of pattern recognition involved in semiquantitative scoring of immunohistochemistry slides. As a side results, this study highlights the value of computer-generated images to verify the performance of image-analysis software.  相似文献   
3.
《Diagnostic Histopathology》2022,28(11):493-500
After decades of relative stagnation lung cancer is emerging as a disease type where rapid progress is being made in diagnosis and therapy, as well as in our understanding of disease biology. Much of this progress is of immediate impact to diagnosticians, and more is likely to affect diagnostic practice in the near future. In this review we seek to briefly summarize several key areas of active research of immediate or probable imminent value to trainee and consultant pulmonary pathologists alike. We cover some major changes in tumour classification, grading, and patient stratification, as well as considering the state of the art in machine-assisted interpretation of lung cancer histology, and the use of genetically modified lung cancer models.  相似文献   
4.

Objective

To examine the experience of interracial anxiety among health professionals and how it may affect the quality of their interactions with patients from racially marginalized populations. We explored the influence of prior interracial exposure—specifically through childhood neighborhoods, college student bodies, and friend groups—on interracial anxiety among medical students and residents. We also examined whether levels of interracial anxiety change from medical school through residency.

Data Source

Web-based longitudinal survey data from the Medical Student Cognitive Habits and Growth Evaluation Study.

Study Design

We used a retrospective longitudinal design with four observations for each trainee. The study population consisted of non-Black US medical trainees surveyed in their 1st and 4th years of medical school and 2nd and 3rd years of residency. Mixed effects longitudinal models were used to assess predictors of interracial anxiety and assess changes in interracial anxiety scores over time.

Principal Findings

In total, 3155 non-Black medical trainees were followed for 7 years. Seventy-eight percent grew up in predominantly White neighborhoods. Living in predominantly White neighborhoods and having less racially diverse friends were associated with higher levels of interracial anxiety among medical trainees. Trainees' interracial anxiety scores did not substantially change over time; interracial anxiety was highest in the 1st year of medical school, lowest in the 4th year, and increased slightly during residency.

Conclusions

Neighborhood and friend group composition had independent effects on interracial anxiety, indicating that premedical racial socialization may affect medical trainees' preparedness to interact effectively with diverse patient populations. Additionally, the lack of substantial change in interracial anxiety throughout medical training suggests the importance of providing curricular tools and structure (e.g., instituting interracial cooperative learning activities) to foster the development of healthy interracial relationships.  相似文献   
5.
目的 分析2013-2019年中国31省市中医药资源配置水平及区域差异,探讨影响资源配置水平的主要因素,为优化中国中医药资源配置提供依据。方法 选取具有代表性的每万人口中医药机构数、每万人口中医药技术人员以及每万人口中医药床位数作为中医药资源配置水平的指标,利用统计年鉴2013-2019年的面板数据,综合运用熵权法、可分解的泰尔指数以及面板时间固定效应模型,分析各省份中医药资源配置水平及区域公平性差异和影响因素。结果 中国中医药资源配置水平均值为0.165,整体呈现递增趋势,不同省份间配置水平有差异;按人口配置的总体泰尔指数优于按面积配置的指数;公平性差异主要来自于四大经济区区域内差异;经济发展水平、城镇化水平和财政自主度是影响中医药资源配置的主要因素(P<0.05)。结论 中医药资源配置整体水平呈增长趋势,资源配置的公平性有待于进一步提高,应重点关注区域内的不公平性。经济发展水平、城镇化水平和财政自主度是影响中医药资源配置水平的主要因素,建议各地区根据当地不同现状精准施策。  相似文献   
6.
With increased access to smartphones, the selfie has gained immense popularity in the past decade. Selfie images could be a significant source of ante-mortem (AM) image data in cases where dental records are unavailable or considered insufficient. The application of 3D imaging and selfies has not been explored to its full potential in human dental identification. The present study aimed to evaluate the feasibility of using selfies as AM data and comparing with 3D post-mortem (PM) scans as an alternative to multiple 2D PM photographs in forensic dental identification. The study sample consisted of 18 selfies (12 matching and 6 non-matching) and 15 3D dental scans obtained from the study participants. The study sample was assessed by 6 experienced forensic odontologists (Raters) in two phases; Phase I-Visual comparison of 2D selfies to 3D scans and Phase II-2D selfies superimposed upon 3D scans. Each rater looked at 15 cases, and a total of 1620 comparisons were made by 6 raters (72 for the 12 matching cases and 1548 were for non-matching) and the opinions for each of the comparisons were analyzed. The results of the study show that use of the 3D superimposition method increased the certainty of the conclusions reached by the raters for the cases with correct matches. Furthermore, 94.2% of the 1548 non-matching comparisons were correctly excluded, compared with 77% for the 2D visual comparison method. The study demonstrated the applicability of this 3D method as a valuable tool in assisting the forensic odontologist with dental identification using selfies.  相似文献   
7.
《Molecular therapy》2022,30(8):2856-2867
  1. Download : Download high-res image (173KB)
  2. Download : Download full-size image
  相似文献   
8.
BackgroundTime series models are widely used forecasting techniques in health care for long time series and are typically built in commercial statistical packages. However, for short time series data, such as health-related quality of life (HRQoL), guidance on how to select and use appropriate time series models is lacking. This tutorial provides a step-by-step guide adopting a time series analysis framework for HRQoL forecasting.ObjectiveWe walk through a case study examining the forecasting of the effects of adjuvant endocrine therapy on the HRQoL of post-menopausal women with non-metastatic ER + breast cancer using data from the HRQoL sub-protocol of the Tamoxifen arm of the Arimidex, tamoxifen, alone or in combination (ATAC) trial.MethodsThe forecasting of HRQoL consists of four steps: 1) data extraction and accuracy check, 2) forecasting horizon definition and identification of data pattern, 3) forecasting model identification and fitting using five forecasting approaches appropriate for short time series ((i) double exponential smoothing, (ii) double moving average, (iii) fuzzy forecasting, (iv) grey forecasting, and (v) Volterra series), 4) forecasting model selection. A user-friendly visual basic for applications (VBA) Excel add-in is made available to interested users to facilitate the application of the tutorial.ResultsThe Grey method and Volterra series appeared to be good candidates to forecast the effects of adjuvant endocrine therapy on the HRQoL of post-menopausal women with non-metastatic ER + breast cancer enrolled in the ATAC trial.ConclusionIt is feasible to forecast the effects of treatments on HRQOL even when the time series is short.  相似文献   
9.
The incidence of multiple myeloma is increasing as the proportion of older adults is growing rapidly. A critical evaluation of the evidence available is needed to guide the management of older patients with myeloma. A systematic review was conducted to report the prognostic value of geriatric assessment and frailty scores in older patients with multiple myeloma. We conducted a literature search in February and August 2018. Two researchers extracted the data and assessed the quality of the studies. Geriatric assessment and frailty scores were defined as those evaluating at least 2 geriatric domains. Main outcomes were mortality or toxicity. We estimated the pooled hazard ratios (HR) with 95% confidence intervals (CIs) using a random-effects model. We screened titles and abstracts of 1672 citations for eligibility. Seven studies were included in the qualitative analysis, of which 3 were included in the meta-analysis. Two studies reported similar risks of hematologic adverse events in intermediate-fit and in frail patients compared to frail, but a significantly increased risk of nonhematologic adverse events in frail patients compared to fit patients. In meta-analysis, a significantly increased HR for death was observed in patients with activity of daily living score ≤ 4 (pooled HR = 1.576; 95% CI, 1.051-2.102; χ2 = 0.87; P = .647; I2 = 0). Patients classified as frail showed higher risk of death than fit patients (pooled HR = 2.169; 95% CI, 1.002-2.336; χ2 = 3.02; P = .221; I2 = 33.7%). GA and frailty score are effective in predicting mortality in older adults with myeloma.  相似文献   
10.
IntroductionPrenatal exposure to di(2-ethylhexyl) phthalate (DEHP) has been reported to be associated with adverse effects on neurodevelopment that yield behavior syndromes in young children with an estimated median exposure lower than the currently recommended tolerable daily intake (TDI) and reference dose (RfD).ObjectivesOur aim was to derive the benchmark dose for prenatal exposure to DEHP for the neurodevelopmental health in children.MethodsA total of 122 mother-child pairs from the Taiwan Maternal and Infant Cohort Study were analyzed for the dose-response relationship between maternal exposure to DEHP and children's behavioral syndromes evaluated at 8 years (n = 122, 2009), 11 years (n = 96, 2012), and 14 years (n = 78, 2015) of age. We employed a multivariate regression model to assess the statistical associations between the estimated maternal average daily intake of DEHP and child's individual CBCL scores for boys and girls at each separate age, followed by a mixed model for all the children across three ages accounting for individual variations. We then employed structural equation models by combining the children's specific behavioral problem scores at different ages and obtained a simulated overall latent score in relation to maternal exposure. Based on the established dose-response relationship, we derived the benchmark dose (BMD) and the lower limit (BMDL).ResultsAssociations of maternal DEHP exposure (median 4.54μg/kg_bw/day) with the Child Behavior Checklist (CBCL) scores were all significant, except for somatic complaints, adjusting for child's age, gender, IQ, and family income. The BMDL, given a benchmark response of 0.10 (0.05) and a background response of 0.05, was 6.01 (2.16) μg/kg_bw/dayfor an integrated CBCL score.ConclusionsThe current TDI (RfD) of 50 (20) μg/kg_bw/day for DEHP might not protect pregnant women for their children from behavioral problems. There remains the lack of comparable toxicological data. Further investigations are needed.  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