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   217588篇
  免费   3418篇
  国内免费   161篇
耳鼻咽喉   1708篇
儿科学   8928篇
妇产科学   3770篇
基础医学   21480篇
口腔科学   2712篇
临床医学   15473篇
内科学   38653篇
皮肤病学   1917篇
神经病学   19019篇
特种医学   10158篇
外科学   35436篇
综合类   3642篇
一般理论   19篇
预防医学   20136篇
眼科学   4272篇
药学   13653篇
  1篇
中国医学   999篇
肿瘤学   19191篇
  2023年   337篇
  2022年   992篇
  2021年   1897篇
  2020年   1058篇
  2019年   1203篇
  2018年   23204篇
  2017年   18215篇
  2016年   20711篇
  2015年   2392篇
  2014年   3010篇
  2013年   3281篇
  2012年   10501篇
  2011年   24247篇
  2010年   20698篇
  2009年   13044篇
  2008年   21603篇
  2007年   23847篇
  2006年   2650篇
  2005年   4020篇
  2004年   5009篇
  2003年   5722篇
  2002年   3649篇
  2001年   1057篇
  2000年   1131篇
  1999年   769篇
  1998年   474篇
  1997年   430篇
  1996年   321篇
  1995年   296篇
  1994年   257篇
  1993年   200篇
  1992年   422篇
  1991年   446篇
  1990年   494篇
  1989年   418篇
  1988年   349篇
  1987年   298篇
  1986年   270篇
  1985年   278篇
  1984年   203篇
  1983年   151篇
  1982年   97篇
  1981年   83篇
  1980年   112篇
  1979年   120篇
  1978年   83篇
  1977年   100篇
  1976年   77篇
  1974年   76篇
  1970年   68篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Treatment guidelines for management of uncomplicated gonorrhoeae have been recently modified owing to alarming upsurge in azithromycin resistance. This study investigated the prevalence and genetic determinants of gonococcal azithromycin resistance in India. Four (5.7%) of 70 gonococcal isolates were resistant to azithromycin. Of 16 isolates investigated for molecular mechanisms of resistance, 13 (81.3%) and 6 (37.5%) isolates exhibited mutations in coding and promoter regions of mtrR gene, respectively. However, ermA, ermB and ermC genes or mutations in rrl gene were absent in all isolates. Azithromycin resistance is low in India posing no immediate threat to use of dual-therapy for syndromic management.  相似文献   
2.
3.
4.
We report two British cases of liver abscess, due to Klebsiella pneumoniae and associated with synchronous infection elsewhere, which required liver resection for definitive treatment. They illustrate the geographic spread of aggressive K pneumoniae liver infection and demonstrate the importance of early aggressive treatment.  相似文献   
5.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  相似文献   
6.
Pediatric trachyonychia is an acquired nail disease that can cause distress to families. It is a poorly understood disease, and long‐term follow‐up data are lacking. We present an institutional review of 11 children with isolated pediatric trachyonychia followed over time. Children with the diagnosis of pediatric trachyonychia were identified and invited to participate. Pictures were taken on follow‐up and a questionnaire was answered. Exclusion criteria include having another diagnosis at the initial visit that causes nail dystrophy. Eleven patients with the diagnosis of pediatric trachyonychia were available for follow‐up. The mean age of appearance was 2.7 years (range 2–7 yrs) and the average follow‐up was 66 months (range 10–126 mos). Nine patients were treated with potent topical corticosteroids, one used only petrolatum, and one took vitamin supplements. One patient was found to have an additional skin and hair diagnosis of alopecia areata on follow‐up. On follow‐up, 82% noted improvement of the nails, whereas 18% noted no change. A majority of cases of pediatric trachyonychia are isolated and improve with time, regardless of treatment.  相似文献   
7.
8.
9.
10.
Background and aimsWorldwide the COVID-19 pandemic has accelerated sufferings of mental health and behaviour attitudes of people. Many countries, including Bangladesh, reported suicide as extreme consequences of the psychological burden influenced by COVID-19. The present study explores human stress and its factor influenced by COVID-19 in Bangladesh, which significantly affect the quality of life.MethodsAn online-based questionnaire survey was conducted among 651 adult Bangladeshi populations by capturing socio-demographic information, possible human stress, and consequences of the pandemic. A set of statistical tools such as Pearson's Correlation Matrix (PCM), T-test, Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were applied to identify the relationship between different factors and influential factors increasing human stress.ResultsMore than 83% of the participants are facing COVID-19 related mental stress, which results in short temper, sleep disorder, and family chaos. PCA and HCA outcomes indicated a significant relationship between the respondents' opinions and human stress factors, which harmonized with the country's existing scenario. PCM results enlighten the relationship between human stress factors and found financial hardship, cutting back daily spending, and food crisis are interconnected together causes stress. Also, hampering students' formal education and future career plans significantly contribute to mental stress.ConclusionBased on the above findings, it's crucial to introduce a time-oriented strategy and implement precaution monitoring plans for Bangladesh. The rescue plan will help people to manage the pandemic and improve mental health to fight against psychological challenges related to COVID-19 and future pandemics.  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