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   814篇
  免费   23篇
  国内免费   16篇
儿科学   23篇
妇产科学   8篇
基础医学   65篇
口腔科学   17篇
临床医学   44篇
内科学   377篇
皮肤病学   14篇
神经病学   12篇
特种医学   77篇
外科学   37篇
综合类   36篇
预防医学   16篇
眼科学   16篇
药学   25篇
中国医学   1篇
肿瘤学   85篇
  2022年   5篇
  2021年   7篇
  2019年   4篇
  2018年   9篇
  2017年   3篇
  2016年   12篇
  2015年   7篇
  2014年   22篇
  2013年   22篇
  2012年   11篇
  2011年   18篇
  2010年   39篇
  2009年   32篇
  2008年   20篇
  2007年   45篇
  2006年   38篇
  2005年   28篇
  2004年   41篇
  2003年   30篇
  2002年   43篇
  2001年   39篇
  2000年   32篇
  1999年   25篇
  1998年   36篇
  1997年   27篇
  1996年   18篇
  1995年   13篇
  1994年   16篇
  1993年   10篇
  1992年   13篇
  1991年   9篇
  1990年   12篇
  1989年   25篇
  1988年   22篇
  1987年   13篇
  1986年   16篇
  1985年   14篇
  1984年   12篇
  1983年   4篇
  1982年   11篇
  1981年   4篇
  1980年   15篇
  1979年   5篇
  1978年   6篇
  1977年   5篇
  1958年   2篇
  1957年   1篇
  1955年   1篇
  1954年   2篇
  1949年   2篇
排序方式: 共有853条查询结果,搜索用时 15 毫秒
81.
Founder effect in spinal and bulbar muscular atrophy (SBMA)   总被引:3,自引:2,他引:3  
We analyzed the polymorphic (CAG)n and (GGC)n repeats of the androgen receptor gene in 113 unrelated X-linked spinal and bulbar muscular atrophy (SBMA) X chromosomes and 173 control X chromosomes in Japanese males. The control chromosomes had an average CAG repeat number of 21 +/- 3 with a range from 14-32 repeat units, and SBMA chromosomes had a range from 40-55 with a median of 47 +/- 3 copies. The control chromosomes had seven different alleles of the (GGC)n repeat with the range of 11 to 17; the most frequent size of (GGC)n was 16 (79%), while (GGC)17 was very rare (1%). However, in SBMA chromosomes only two alleles were seen; the most frequent size of (GGC)n was 16 (61%) followed by 17 (39%). (GGC)n size distribution was significantly different between SBMA and control chromosomes (P < 0.0001), indicating the presence of linkage disequilibrium. There was no allelic association between the (CAG)n and (GGC)n microsatellites among control subjects as well as SBMA patients, which suggests that a founder effect makes a more significant contribution to generation of Japanese SBMA chromosomes than new mutations.   相似文献   
82.
Little information is available on the profile of suicidal mentally ill sufferers seeking help from helplines. In this article we describe the profile and experience with services of suicidal people calling SANELINE, a national mental health helpline in the UK. Analyses were conducted on 1,331 calls made during 1996-1997 by callers who resided in London. Sixty-one percent of all callers were female. Half of all callers were suffering from depression and 32% from psychosis. Psychotic sufferers were significantly more likely not to have been complying with treatment, to have wanted information about medication, and to have been dissatisfied with the local services. Suicidal psychotic sufferers were more likely than non-suicidal ones to have inquired about mental health laws or about state benefits. On the other hand, depressive sufferers were more likely to have wanted information about social support groups, and to have complained about the lack of services in their area of residence. The findings suggested the need to target male sufferers, to meet the information needs of suicidal people with psychosis or depression, and to increase awareness about available sources of help.  相似文献   
83.
84.
Thyroid dysfunction can develop in patients with Hodgkin's disease who are treated with mantle irradiation. During the period 1970-89, the records of 320 patients who received mantle irradiation and who had thyroid function tests (TFT) were retrospectively reviewed. The median age was 30 years (range, 7-69 years). The median mantle and thyroid dose was 36 Gy (range, 30-40 Gy) and 39.8 Gy (range, 32-65 Gy), respectively. Overall thyroid dysfunction was present in 39% of the patients. Clinical hypothyroidism was seen in 10% and biochemical hypothyroidism was noted in 25%. Hyperthyroidism was found in 4% of patients. Thyroid nodules had developed in six patients (2%), of which those in four patients were malignant. Age, sex, histological subtype, stage of disease, dose, lymphangiogram and treatment with chemotherapy were not significant factors in the development of thyroid dysfunction. The narrow dose range prevented adequate analysis of dose effect. The results indicate that the incidence of thyroid abnormalities is high enough to warrant regular TFT assessment with pre-irradiation levels and follow-up testing for life because the development of abnormalities can occur many years later. Thyroid examination should form part of the routine follow-up examination and any abnormality should be promptly investigated.  相似文献   
85.
In healthy individuals, Candida species are considered commensal yeasts of the oral cavity. However, these microorganisms can also act as opportunist pathogens, particularly the so‐called non‐albicans Candida species that are increasingly recognized as important agents of human infection. Several surveys have documented increased rates of C. glabrata, C. tropicalis, C. guilliermondii, C. dubliniensis, C. parapsilosis, and C. krusei in local and systemic fungal infections. Some of these species are resistant to antifungal agents. Consequently, rapid and correct identification of species can play an important role in the management of candidiasis. Conventional methods for identification of Candida species are based on morphological and physiological attributes. However, accurate identification of all isolates from clinical samples is often complex and time‐consuming. Hence, several manual and automated rapid commercial systems for identifying these organisms have been developed, some of which may have significant sensitivity issues. To overcome these limitations, newer molecular typing techniques have been developed that allow accurate and rapid identification of Candida species. This study reviewed the current state of identification methods for yeasts, particularly Candida species.  相似文献   
86.
Both electrocautery and internal defibrillation are routinely used in cardiac operations. The cases of 5 patients are presented in whom backup-mode reversion or injury of permanently implanted pulse generators occurred during a cardiac procedure. The theoretical explanations for backup-mode reversion and generator or tissue injury are discussed, and recommendations are made for the management of patients with a pacemaker who are to undergo a cardiac operation.  相似文献   
87.
High-dose ifosfamide with mesna uroprotection: a phase I study   总被引:3,自引:0,他引:3  
Phase II trials of ifosfamide have been performed with standard doses of 5 to 8 g/m2/course. In this phase I study, 29 patients were treated with a 4-day continuous infusion ifosfamide to determine the maximum-tolerated dose and the nonhematologic dose-limiting toxicity. Autologous bone marrow support was to have been used for the subsequent dose level if granulocytes were more than 500/microL for more than 14 days in two of two to five patients at a given dose level. Doses were escalated from 8 to 18 g/m2 ifosfamide. Mesna was given at an equivalent dose by continuous infusion for 5 days. At the 18 g/m2 dose level, dose-limiting renal insufficiency and a median of 11 days (range, 8 to 18 days) of granulocytopenia (less than 500/microL) were observed. Thus, autologous bone marrow reinfusion ws not used. The duration of myelosuppression, the frequency and severity of mucositis, and renal tubular acidosis were all dose-dependent. Mild to moderate CNS toxicity also appeared to be related to dose; however, severe CNS toxicity (transient confusion, hallucinations, and somnolence) was observed sporadically at both low- and high-dose levels. Transient hematuria (greater than 50 red blood cells [RBCs]/high power field) occurred once but did not affect treatment. There were nine responses (two complete) in 27 heavily pretreated assessable patients including seven responses in 20 patients with advanced refractory sarcoma. Ifosfamide with mesna uroprotection can undergo considerable dose escalation over the usual prescribed doses before nonhematologic dose-limiting toxicity is encountered. Ifosfamide has broad cytotoxicity against solid tumors and may prove to be an important addition to high-dose combination chemotherapy regimens.  相似文献   
88.
89.
人工关节置换术是矫正关节畸形、解除关节疼痛、重建关节功能的主要手段。多年来 ,人工全髋、全膝皆以聚乙烯为关节形成表面 ,随着人工关节置换的广泛开展 ,聚乙烯磨损问题越来越引起人们的关注。聚乙烯磨损及其产生的碎屑和磨损颗粒所引发的生物学反应及导致的骨吸收、骨溶解 ,是造成假体松动、人工关节翻修的主要原因[1,2 ] 。与人工髋关节的球洞几何形态相比 ,人工膝关节的几何形态要不吻合的多 ,胫骨假体表面常承受较大的接触应力 ,较易产生磨损[2 ,3 ] ,理论上关节形成表面越吻合 ,聚乙烯磨损越少 ,不同的胫股关节吻合性 ,对假体磨损产…  相似文献   
90.
BACKGROUND: The Thrombolysis in Myocardial Infarction (TIMI) Study Group originally defined TIMI grade 3 flow (complete perfusion) as antegrade flow into the bed distal to the obstruction that occurs as promptly as antegrade flow into the bed proximal to the obstruction. Recently, several groups have defined TIMI grade 3 flow as opacification of the coronary artery within 3 cardiac cycles. METHODS AND RESULTS: On the basis of heart rate data at the time of the cardiac catheterization and the time for dye to go down the artery (TIMI frame count/30 = seconds), we estimated the number of patients who would meet the 3 cardiac cycle criterion and compared this with the number of patients with TIMI grade 3 flow by using the original definition in 1157 patients from 3 recent TIMI trials (10 A, 10B, and 14). In 74 patients without acute myocardial infarction and normal coronary arteries, the fraction of a cardiac cycle required for dye to traverse the artery was a mean of 0.93 +/- 0.34 cardiac cycles (n = 74) (median 0.80, minimum 0.44, maximum 2.1, none >3.0 cycles). The mean heart rate at 90 minutes after thrombolysis in the TIMI 14 trial was 79.6 +/- 16.8 beats/min (n = 194), and the duration of 3 cardiac cycles was a mean of 2.36 seconds, or a TIMI frame count of 70.8 frames. In all trials, the rate of TIMI grade 3 flow was 57.3% (n = 663/1157) with the original definition and 66.8% (n = 743/1113) with the <3 cardiac cycle definition (P <.001). CONCLUSIONS: A duration of 3 cardiac cycles for dye to traverse the artery lies approximately 6 SD above that observed in normal coronary arteries. A 3 cardiac cycle definition of TIMI grade 3 flow results in rates of normal perfusion that are approximately 10% higher than if the original definition of TIMI grade 3 flow is applied. Application of this simple correction factor may help place data reported with the 3 cardiac cycle definition of TIMI grade 3 flow in context.  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