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   3344篇
  免费   254篇
  国内免费   14篇
耳鼻咽喉   50篇
儿科学   93篇
妇产科学   94篇
基础医学   470篇
口腔科学   44篇
临床医学   312篇
内科学   777篇
皮肤病学   82篇
神经病学   386篇
特种医学   92篇
外科学   316篇
综合类   20篇
一般理论   1篇
预防医学   286篇
眼科学   91篇
药学   178篇
中国医学   5篇
肿瘤学   315篇
  2024年   6篇
  2023年   55篇
  2022年   109篇
  2021年   227篇
  2020年   96篇
  2019年   134篇
  2018年   150篇
  2017年   107篇
  2016年   104篇
  2015年   116篇
  2014年   169篇
  2013年   182篇
  2012年   272篇
  2011年   301篇
  2010年   143篇
  2009年   133篇
  2008年   211篇
  2007年   226篇
  2006年   201篇
  2005年   167篇
  2004年   146篇
  2003年   113篇
  2002年   110篇
  2001年   9篇
  2000年   7篇
  1999年   16篇
  1998年   14篇
  1997年   10篇
  1996年   12篇
  1995年   9篇
  1994年   8篇
  1993年   5篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   5篇
  1988年   4篇
  1986年   6篇
  1985年   3篇
  1984年   2篇
  1981年   3篇
  1980年   2篇
  1963年   1篇
  1946年   1篇
  1940年   1篇
  1938年   1篇
  1923年   1篇
  1911年   1篇
  1907年   1篇
  1905年   1篇
排序方式: 共有3612条查询结果,搜索用时 15 毫秒
81.
ABSTRACT: BACKGROUND: Severe renal manifestation of systemic lupus erythematosus (SLE) is not uncommon and is associated with an indeterminate prognosis. Complete remission can be obtained, however, at least in the young when chronic lesions are absent and adequate anti-inflammatory therapy is immediately initiated. CASE PRESENTATION: We report the unusual case of a 12-year-old girl who presented with severe oliguric renal failure, macrohematuria and skin rash. Renal biopsy revealed the diagnosis of severe diffuse proliferative glomerulonephritis (GN) with cellular crescents in 15 out of 18 glomeruli and full-house pattern in immunofluorescence indicating lupus nephritis IVB according to WHO, IV-G(A) according to ISN/RPS classification. The serological parameters confirmed the diagnosis of (SLE and the patient was immediately treated with methylprednisolone, cyclophoshamide and immunoadsorption. Initially, despite rapid amelioration of her general condition, no substantial improvement of renal function could be achieved and the patient needed hemodialysis treatment for 12 weeks. Unexpectedly, in the further follow-up at first diuresis increased and thereafter also creatinine levels substantially declined so that hemodialysis could be discontinued. Today, 6 years after the initial presentation, the patient has normal renal function and a SLEDAI score of 0 under a continous immunosuppressive therapy with Mycophenolate mofetil (MMF). CONCLUSION: Despite the severity of the initial renal injury and the unfavourable renal prognosis the kidney apparentlyhas a tremendous capacity to recover in young patients when the damage is acute and adequate anti-inflammatory therapy is initiated without delay.  相似文献   
82.
Tooth wear is a relevant oral health problem, especially at a young age. Although ongoing acid exposures may contribute to tooth wear, the role of acidic dietary components in this context remains unclear. To date, in tooth wear studies, dietary behavior has been assessed using traditional questionnaires, but the suitability of this approach has not been investigated so far. In our longitudinal study, we followed 91 participants (21.0 ± 2.2 years) over a period of 1 year (373 ± 19 days) and monitored tooth wear with an intraoral scanner. At baseline (T0) and at the end (T1), we assessed dietary behavior with questionnaires asking about the consumption frequencies of acidic dietary components and the acid taste preferences. Complete data were available from 80 subjects. The consumption frequencies of T0 and T1 correlated weakly to moderately. Taste preferences seem to be a more consistent measure, but there was predominantly no significant correlation with the corresponding consumption frequencies. None of the dietary parameters showed a significant relation with tooth wear. The suitability of dietary questionnaires to assess tooth-relevant dietary behavior seems to be limited.  相似文献   
83.
Objective: Just-in-time training (JITT) has been used to teach and re-teach known medical techniques, but has not been used to teach novel techniques. We aimed to assess the performance retention of JITT on a novel asthma exacerbation severity assessment technique known as Los Angeles (LA) Phonospirometry. Methods: This was a prospective cohort study using a convenience sample of pediatric emergency department registered nurses (RNs) who were asked to watch a brief instructional digital video on LA Phonospirometry, and then asked to practice the technique on a research assistant (RA). A checklist was used to evaluate proficiency with the primary outcome being the number correct on the checklist. The secondary outcome included whether or not they could identify a common error demonstrated by the RA. RNs were re-tested after 4–6 months to assess skill retention. Results: Forty RNs were enrolled in the study and six were lost to follow-up. The mean time from the first to second testing was 5.4 months ± 0.5 months. The mean score of the first part of the checklist on the initial testing was 4.6 ± 0.7 and on second testing was 3.8 ± 1.5 (p = 0.008). This represented a drop in scores and thus minimal knowledge decay of 18% (from 91% to 73%). The mean values for number of errors picked up for the first test and second test were 1.3 and 1.5, respectively (p = 0.2). Conclusions: JITT demonstrated feasibility as a rapid instructional tool for RNs, with a limited decay in cognitive knowledge surrounding the LA Phonospirometry technique.  相似文献   
84.
85.
86.
The publication of “The Sleep Apnea Syndromes” by Guilleminault et al. in the 1970s hallmarked the discovery of a new disease entity involving serious health consequences. Obstructive sleep apnea was shown to be the most important disorder among the sleep apnea syndromes (SAS). In the course of time, it was found that the prevalence of obstructive sleep apnea reached the proportions of a global epidemic, with a major impact on public health, safety and the economy. Early on, a metric was introduced to gauge the seriousness of obstructive sleep apnea, based on the objective measurement of respiratory events during nocturnal sleep. The apnea index and later on the apnea?hypopnea index, being the total count of overnight respiratory events divided by the total sleep time in hours, were embraced as principle measures to establish the diagnosis of obstructive sleep apnea and to rate its severity. The current review summarises the historical evolution of the apnea?hypopnea index, which has been subject to many changes, and has been criticised for not capturing relevant clinical features of obstructive sleep apnea. In fact, the application of the apnea?hypopnea index as a continuous exposure variable is based on assumptions that it represents a disease state of obstructive sleep apnea and that evocative clinical manifestations are invariably caused by obstructive sleep apnea if the apnea?hypopnea index is above diagnostic threshold. A critical appraisal of the extensive literature shows that both assumptions are invalid. This conclusion prompts a reconsideration of the role of the apnea?hypopnea index as the prime diagnostic metric of clinically relevant obstructive sleep apnea.  相似文献   
87.
88.
89.
90.
The presence of Y chromosome sequences in Turner syndrome (TS) patients may predispose them to gonadoblastoma formation with an estimated risk of 15–25%. The aim of this study was to determine the presence and the incidence of cryptic Y chromosome material in the genome of TS patients. The methodology involved a combination of polymerase chain reaction (PCR) and nested PCR followed by Southern blot analysis of three genes—the sex determining region Y (SRY), testis specific protein Y encoded (TSPY) and RNA binding motif protein (RBM) (previously designated as YRRM) and nine additional STSs spanning all seven intervals of the Y chromosome. The methodology has a high sensitivity as it detects one 46, XY cell among 105 46, XX cells. Reliability was ensured by taking several precautions to avoid false positive results. We report the results of screening 50 TS patients and the identification of cryptic Y chromosome material in 12 (24%) of them. Karyotypes were divided in four groups: 5 (23.8%) patients out of the 21 TS patients which have the 45, X karyotype (group A) also have cryptic Y sequences; none (0%) of the 7 patients who have karyotypes with anomalies on one of the X chromosomes have Y mosaicism (group B); 1 (6.3%) of the 16 patients with a mosaic karyotype have Y material (group C); and 6 (100%) out of 6 patients with a supernumerary marker chromosome (SMC) have Y chromosome sequences (group D). Nine of the 12 patients positive for cryptic Y material were recalled for a repeat study. Following new DNA extraction, molecular analysis was repeated and, in conjunction with fluorescent in situ hybridization (FISH) analysis using the Y centromeric specific probe Yc-2, confirmed the initial positive DNA findings. This study used a reliable and sensitive methodology to identify the presence of Y chromosome material in TS patients thus providing not only a better estimate of a patient's risk in developing either gonadoblastoma or another form of gonadal tumor but also the overall incidence of cryptic Y mosaicism.  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