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   409篇
  免费   29篇
耳鼻咽喉   38篇
儿科学   8篇
妇产科学   7篇
基础医学   64篇
临床医学   21篇
内科学   69篇
皮肤病学   19篇
神经病学   6篇
特种医学   3篇
外科学   118篇
综合类   4篇
预防医学   24篇
眼科学   4篇
药学   16篇
肿瘤学   37篇
  2023年   3篇
  2022年   5篇
  2021年   10篇
  2020年   5篇
  2019年   4篇
  2018年   15篇
  2017年   5篇
  2016年   9篇
  2015年   11篇
  2014年   13篇
  2013年   16篇
  2012年   31篇
  2011年   39篇
  2010年   10篇
  2009年   22篇
  2008年   16篇
  2007年   27篇
  2006年   30篇
  2005年   26篇
  2004年   30篇
  2003年   30篇
  2002年   23篇
  2001年   4篇
  2000年   3篇
  1999年   5篇
  1998年   5篇
  1996年   2篇
  1994年   4篇
  1992年   4篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1969年   1篇
  1965年   1篇
  1963年   1篇
  1962年   1篇
  1961年   1篇
  1957年   1篇
  1956年   1篇
  1955年   1篇
  1954年   1篇
  1945年   2篇
  1944年   1篇
  1943年   3篇
  1942年   2篇
  1941年   1篇
  1940年   2篇
  1924年   1篇
排序方式: 共有438条查询结果,搜索用时 15 毫秒
1.
Lymphoid neogenesis is the process by which ectopic lymphoid accumulations that resemble lymph nodes arise in nonlymphoid tissues. Such lymphoid accumulations, known as tertiary lymphoid organs (TLO), are observed in chronic autoimmunity and they propagate immune pathology by setting up local antigen presenting sites. Whether lymphoid neogenesis occurs in transplanted organs and contributes to rejection is not well understood. To begin to address this question, we retrospectively analyzed 319 murine cardiac allografts for microscopic evidence of lymph-node-like structures. We found 78 allografts that had either classical TLO, characterized by discrete T- and B-cell zones and high endothelial venules (HEV) expressing peripheral node addressin (PNAd) (n = 34), or PNAd(+) HEV without organized lymphoid accumulations (n = 44). These changes were present in both short- and long-lived allografts and were invariably associated with rejection. Importantly, they occurred in 78% of allografts undergoing chronic rejection (n = 85) but in only 7% of allografts undergoing primarily acute rejection (n = 184). These findings indicate that, like autoimmunity, alloimmunity is associated with lymphoid neogenesis in the target organ and suggest a role for local T-cell activation in chronic allograft rejection.  相似文献   
2.

Background  

The aim of the current study is to investigate the relationship between physical anhedonia and psychopathological parameters, pharmacological parameters or motor side-effects in a sample of inpatients with schizophrenia in an acute episode of their illness.  相似文献   
3.
Our objectives were to devise a cytologic grading system and determine whether it would predict survival of patients with solid-type pancreatic adenocarcinoma. We evaluated 116 consecutive patients from July 2000 to November 2002; they were followed up until September 2003. We scored the following features on rapid Romanowsky-stained endoscopic ultrasound-guided fine-needle aspiration smears: cell group architecture, single cells, nuclear grade, mucus, bizarre cells, and necrosis. A cytologic grade (low vs high) was assigned. The Kaplan-Meier estimate of 6-month survival was 76% (SE, 7%) for patients with low-grade tumors vs 50% (SE, 6%) for patients with high-grade carcinoma. The median survival for patients with low-grade vs high-grade tumors was 1 year vs 6 months, respectively (chi2 = 4.45; P = .035). Cox proportional hazards regression showed tumor stage, cancer-specific treatment, and cytologic grade to be independent predictors of survival (P = .001). No other factors (age, mass location, placement of stent, presence of concomitant chronic pancreatitis, race, sex) predicted survival. We devised a grading system that independently predicted survival in patients with pancreatic adenocarcinoma.  相似文献   
4.
Inaccurate reporting of the absence of an endocervical (EC) component on Pap smears often results in slide rescreens, amended reports, clinician dissatisfaction, and sometimes unnecessary repeat smears. Therefore, the accuracy of reporting EC component adequacy was selected as a quality indicator for the laboratory continuous quality improvement program (CQI). The process consisted of problem identification, analysis of the situation, collection of data, implementation of solutions, and evaluation of results. The objective of the study was to determine if the accuracy of reporting EC component adequacy on Pap smears improved after application of such a program. During the first phase, 150 Pap smears originally reported with the absence of an adequate EC component and 150 smears reported with the presence of an adequate EC component were rescreened to measure the baseline accuracy of EC component adequacy reporting. The improvement process was then implemented. A cause-and-effect diagram was developed and root cause was determined. A presentation was then made to the cytology staff. Criteria for EC component adequacy were reviewed, examples were shown, and standardized marking of EC component was implemented. Following improvement actions, a second audit of 150 Pap smears reported with the absence of an adequate EC component as well as 150 smears reported with the presence of an adequate EC component was undertaken to measure change in performance in assessing EC component adequacy. For the baseline rescreening, before initiation of the CQI program, 98% accuracy was achieved with smears that were reported as adequate for EC component present. However, the accuracy with smears reported as absence of an adequate EC component was only 71%, i.e., an adequate EC component was identified in almost 1/3 of these cases on rescreen. After the implementation of improvement actions, the accuracy with smears reported with the presence of EC component remained high (98%) and the accuracy of reporting the absence of EC component was 90%. The difference of the latter before and after the implementation was statistically significant (P = 0.015, z-test). The accuracy of reporting EC component adequacy increased following the CQI process. Using reporting EC component adequacy as an example, we demonstrate that by treating clinical problems as quality control issues and applying basic quality improvement tools, a positive outcome can be effected.  相似文献   
5.
IntroductionGrowing interest surrounds the concept of en bloc transurethral resection of bladder tumors (ERBT). Theoretical advantages include improved adherence to oncological principles and potential yield of superior pathological specimens. Multiple ERBT methods exist. This review summarizes the current evidence regarding application of differing techniques and technologies to ERBT.MethodsA systematic review of MEDLINE/EMBASE/Scopus databases was performed, using terms “en bloc,” “ERBT,” “bladder,” and “urinary bladder neoplasm.” Template-based data extraction included technique of ERBT, feasibility, tumor size, activation of obturator nerve reflex, operative complications, detrusor muscle sampling rate, and recurrence data.ResultsMultiple approaches to ERBT have evolved, using a variety of energy sources. The feasibility of electrocautery, laser, combined waterjet/electrocautery, and polypectomy snare techniques have been confirmed in achieving ERBT. ERBT appears safe, with a low complication rate. The use of laser energy sources reduces the risk of activating the obturator nerve reflex during lateral wall resections. Otherwise, no energy source is unequivocally superior in achieving ERBT. The rate of detrusor muscle sampling is high with use of ERBT and appears superior to that achieved with conventional TURBT (cTURBT) in multiple comparative studies. A limited number of largely non-randomized trials assess bladder tumor recurrence; current evidence suggests this is similar between ERBT and cTURBT groups.ConclusionsERBT using a variety of technologies is feasible and safe, with a high detrusor muscle sampling rate. Further research is required to determine whether rates of residual disease or recurrence can be reduced with ERBT vs. cTURBT.  相似文献   
6.
Locally advanced cervical cancer with congenital pelvic kidney is reported uncommonly. A 50-year-old patient with stage IIB cervical cancer and pelvic kidney was treated with irradiation and concurrent chemotherapy. Follow-up evaluation for 2 years revealed normal renal function and no evidence of recurrent disease.  相似文献   
7.
8.
9.
Seeding cells into porous ceramic substrates has been shown to improve outcomes in surgical repair of large bone defects, but the physics underlying cellular ingress into such scaffolds remains elusive. This paper demonstrates capillary forces as a novel, yet simple, self-loading or self-seeding mechanism for rigid, microporous substrates. Capillary forces were found to draw cells through a microporous network with interconnections smaller than the diameter of the cells in suspension. Work here emphasizes CaP-based bone scaffolds containing both macroporosity (>100 μm) and microporosity (5–50 μm); these have been shown to improve bone formation in vivo as compared to their macroporous counterparts and also performed better than microporous scaffolds containing BMP-2 by some measures of bone regeneration. We hypothesize that capillary force driven self-seeding in both macro- and micropores may underlie this improvement, and present a mathematical model and experiments that support this hypothesis. The cell localization and penetration depth within these two-dimensional substrates in vitro depends upon both the cell type (size and stiffness) and the capillary forces generated by the microstructure. Additional experiments showing that cell penetration depth in vitro depends on cell size and stiffness suggest that microporosity could be tailored to optimize cell infiltration in a cell-specific way. Endogenous cells are also drawn into the microporous network in vivo. Results have important implications for design of scaffolds for the healing of large bone defects, and for controlled release of drugs in vivo.  相似文献   
10.
The effect of diet on the composition of gut microbiota and the consequent impact on disease risk have been of expanding interest. The present review focuses on current insights of changes associated with dietary protein-induced gut microbial populations and examines their potential roles in the metabolism, health, and disease of animals. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol was used, and 29 highly relevant articles were obtained, which included 6 mouse studies, 7 pig studies, 15 rat studies, and 1 in vitro study. Analysis of these studies indicated that several factors, such as protein source, protein content, dietary composition (such as carbohydrate content), glycation of protein, processing factors, and protein oxidation, affect the digestibility and bioavailability of dietary proteins. These factors can influence protein fermentation, absorption, and functional properties in the gut and, consequently, impact the composition of gut microbiota and affect human health. While gut microbiota can release metabolites that can affect host physiology either positively or negatively, the selection of quality of protein and suitable food processing conditions are important to have a positive effect of dietary protein on gut microbiota and human health.  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