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   4610篇
  免费   348篇
  国内免费   7篇
耳鼻咽喉   102篇
儿科学   71篇
妇产科学   97篇
基础医学   641篇
口腔科学   79篇
临床医学   547篇
内科学   730篇
皮肤病学   59篇
神经病学   422篇
特种医学   162篇
外科学   724篇
综合类   37篇
一般理论   5篇
预防医学   509篇
眼科学   128篇
药学   323篇
中国医学   21篇
肿瘤学   308篇
  2023年   40篇
  2022年   100篇
  2021年   260篇
  2020年   102篇
  2019年   184篇
  2018年   176篇
  2017年   133篇
  2016年   114篇
  2015年   138篇
  2014年   207篇
  2013年   240篇
  2012年   344篇
  2011年   323篇
  2010年   143篇
  2009年   132篇
  2008年   195篇
  2007年   192篇
  2006年   191篇
  2005年   145篇
  2004年   151篇
  2003年   132篇
  2002年   136篇
  2001年   60篇
  2000年   58篇
  1999年   49篇
  1998年   25篇
  1997年   22篇
  1996年   21篇
  1995年   20篇
  1992年   45篇
  1991年   47篇
  1990年   52篇
  1989年   63篇
  1988年   41篇
  1987年   52篇
  1986年   47篇
  1985年   44篇
  1984年   34篇
  1983年   32篇
  1982年   21篇
  1980年   25篇
  1979年   22篇
  1978年   27篇
  1977年   24篇
  1975年   31篇
  1974年   21篇
  1973年   25篇
  1972年   24篇
  1971年   24篇
  1970年   29篇
排序方式: 共有4965条查询结果,搜索用时 46 毫秒
91.
92.
Introduction: Epigenetic mechanisms of gene regulatory control play fundamental roles in developmental morphogenesis, and, as more recently appreciated, are heavily implicated in the onset and progression of neoplastic disease, including cancer. Many epigenetic mechanisms are therapeutically targetable, providing additional incentive for understanding of their contribution to cancer and other types of neoplasia.

Areas covered: The Jumonji-domain histone demethylase (JHDM) family exemplifies many of the above traits. This review summarizes the current state of knowledge of the functions and pharmacologic targeting of JHDMs in cancer and other neoplastic processes, with an emphasis on diseases affecting the pediatric population.

Expert opinion: To date, the JHDM family has largely been studied in the context of normal development and adult cancers. In contrast, comparatively few studies have addressed JHDM biology in cancer and other neoplastic diseases of childhood, especially solid (non-hematopoietic) neoplasms. Encouragingly, the few available examples support important roles for JHDMs in pediatric neoplasia, as well as potential roles for JHDM pharmacologic inhibition in disease management. Further investigations of JHDMs in cancer and other types of neoplasia of childhood can be expected to both enlighten disease biology and inform new approaches to improve disease outcomes.  相似文献   

93.
Non-alcoholic fatty liver disease (NAFLD) often develops in concert with related metabolic diseases, such as obesity, dyslipidemia and insulin resistance. Prolonged lipid accumulation and inflammation can progress to non-alcoholic steatohepatitis (NASH). Although factors associated with the development of NAFLD are known, triggers for the progression of NAFLD to NASH are poorly understood. Recent findings published in The Journal of Pathology reveal the possible regulation of NASH progression by metabolites of the mevalonate pathway. Mevalonate can be converted into the isoprenoids farnesyldiphosphate (FPP) and geranylgeranyl diphosphate (GGPP). GGPP synthase (GGPPS), the enzyme that converts FPP to GGPP, is dysregulated in humans and mice during NASH. Both FPP and GGPP can be conjugated to proteins through prenylation, modifying protein function and localization. Deletion or knockdown of GGPPS favors FPP prenylation (farnesylation) and augments the function of liver kinase B1, an upstream kinase of AMP-activated protein kinase (AMPK). Despite increased AMPK activation, livers in Ggpps-deficient mice on a high-fat diet poorly oxidize lipids due to mitochondrial dysfunction. Although work from Liu et al provides evidence as to the potential importance of the prenylation portion of the mevalonate pathway during NAFLD, future studies are necessary to fully grasp any therapeutic or diagnostic potential. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
94.
95.
Childhood is an important time for the manifestation of psychopathology. Psychopathology is characterized by considerable comorbidity which is mirrored in the underlying neural correlates of psychopathology. Both common and dissociable variations in brain volume have been found across multiple mental disorders in adult and youth samples. However, the majority of these studies used samples with broad age ranges which may obscure developmental differences. The current study examines associations between regional gray matter volumes (GMV) and psychopathology in a large sample of children with a narrowly defined age range. We used data from 9607 children 9–10 years of age collected as part of the Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®). A bifactor model identified a general psychopathology factor that reflects common variance across disorders and specific factors representing internalizing symptoms, ADHD symptoms, and conduct problems. Brain volume was acquired using 3T MRI. After correction for multiple testing, structural equation modeling revealed nearly global inverse associations between regional GMVs and general psychopathology and conduct problems, with associations also found for ADHD symptoms (pfdr-values ≤ 0.048). Age, sex, and race were included as covariates. Sensitivity analyses including total GMV or intracranial volume (ICV) as covariates support this global association, as a large majority of region-specific results became nonsignificant. Sensitivity analyses including income, parental education, and medication use as additional covariates demonstrate largely convergent results. These findings suggest that globally smaller GMVs are a nonspecific risk factor for general psychopathology, and possibly for conduct problems and ADHD as well.Subject terms: Human behaviour, Risk factors, Neuroscience  相似文献   
96.
IntroductionPercutaneous anterior-posterior (AP) screw is an option for posterior malleolus fracture fixation when the fracture fragment can be reduced indirectly by the mean of ligamentotaxis. However, anterior anatomic structures could be injured during screw placement.Materials and methodsEleven below-knee cadavers were employed for the placement of AP screws in an attempt of fixing assumed Haraguchi Type-I posterior malleolar fractures. Three entry points were selected as medial to the anterior tibial tendon (ATT), lateral to the ATT, and lateral to the extensor digitorum longus (EDL). Three AP screws were placed under guidance of fluoroscopy. After dissection, measurements were made (mm) from each screw to nearby structures. Distances were calculated and damage to structures was documented.ResultsMean, minimum, and maximum distances from the medial screw to the greater saphenous vein, TA, EHL, anterior tibial artery (ATA), and deep peroneal nerve (DPN), were 18.1 (12–25) mm, 2.0 (0–5) mm, 13.6 (9–20) mm, 16.6 (9–25) mm, and 20.1 (12–27) mm. From the middle screw to the ATA, DPN, TA, EHL, and EDL, were 1.2 (0–3) mm, 4.9 (3–9) mm, 3.8 (1–7) mm, 0.4 (0–2) mm, and 13.6 (10–18) mm. From the lateral screw to the superficial peroneal nerve (SPN), EDL, DPN, and ATA, were 10.8 (0–16) mm, 1.2 (0–4) mm, 15.9 (11–25) mm, 19 (15–27) mm. The SPN was found partially cut by the lateral screw on 1 specimen.ConclusionsLateral and middle percutaneous AP screw placement put certain anatomic structures at-risk of injury. Medial screw placement did not result in appreciable damage to adjacent structures. Entry point of AP screws should be selected with respect to posterior malleolar fracture and anatomic structures.Level of evidenceIV.  相似文献   
97.
Odorants exert their effects at many levels. Most often, these stimuli are well above detection threshold and allow the investigator to use self-report or behavioral techniques to evaluate odor effects. There are, however, considerable data demonstrating effects for odor stimuli that are below sensory thresholds or are undetected by subjects. In these cases, self-report is of little use, and brain imaging has been very effective in helping to explain these findings. This paper reviews the problem of low-intensity odors and the application of a wide variety of brain imaging techniques to research on this phenomenon. Finally, a model of undetected odor effects and brain imaging is presented to help simplify the variations in nomenclature that are used to describe this field.  相似文献   
98.
99.
Annals of Surgical Oncology -  相似文献   
100.

Background Context

Red flags are questions typically ascertained by providers to screen for serious underlying spinal pathologies. The utility of patient-reported red flags in guiding clinical decision-making for spine care, however, has not been studied.

Purpose

The aim of this study was to quantify the sensitivity and specificity of patient-reported red flags in predicting the presence of serious spinal pathologies.

Study Design

This was a retrospective nested case-control study.

Patient Sample

This study consisted of 120 patients with International Classification of Diseases, Ninth Revision, Clinical Modification codes for spinal pathologies and 380 randomly selected patients, from a population of 4,313 patients seen at a large tertiary care spine clinic between October 9, 2013 and June 30, 2014.

Outcome Measures

The presence of patient-reported red flags and red flags obtained from medical records was verified for chart review. The spinal pathology (ie, malignancy, fractures, infections, or cauda equina syndrome) was noted for each patient.

Methods

The sensitivity and specificity of patient-reported red flags for detecting serious spinal pathologies were calculated from data obtained from the 500 patients. Youden's J was used to rank performance. Agreement between patient-reported red flags and those obtained from medical record review was assessed via Cohen's kappa statistic.

Results

“History of cancer” was the best performing patient-reported red flag to identify malignancy (sensitivity=0.75 [95% confidence intervals, CI 0.53–0.90], specificity=0.79 [95% CI 0.75–0.82]). The best performing patient-reported red flag for fractures was the presence of at least one of the following: “Osteoporosis,” “Steroid use,” and “Trauma” (sensitivity=0.59 [95% CI 0.44–0.72], specificity=0.65 [95% CI 0.60–0.69]). The prevalence of infection and cauda equina diagnoses was insufficient to gauge sensitivity and specificity. Red flags from medical records had better performance than patient-reported red flags. There was poor agreement between patient red flags and those obtained from medical record review.

Conclusions

Patient-reported red flags had low sensitivity and specificity for identification of serious pathologies. They should not be used in insolation to make treatment decisions, although they may be useful to prompt further probing to determine if additional investigation is warranted.  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