全文获取类型
收费全文 | 3271篇 |
免费 | 252篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 103篇 |
妇产科学 | 58篇 |
基础医学 | 433篇 |
口腔科学 | 70篇 |
临床医学 | 346篇 |
内科学 | 880篇 |
皮肤病学 | 58篇 |
神经病学 | 370篇 |
特种医学 | 231篇 |
外国民族医学 | 1篇 |
外科学 | 369篇 |
综合类 | 71篇 |
一般理论 | 5篇 |
预防医学 | 194篇 |
眼科学 | 48篇 |
药学 | 162篇 |
肿瘤学 | 108篇 |
出版年
2021年 | 42篇 |
2019年 | 39篇 |
2018年 | 48篇 |
2017年 | 32篇 |
2016年 | 48篇 |
2015年 | 50篇 |
2014年 | 55篇 |
2013年 | 106篇 |
2012年 | 132篇 |
2011年 | 126篇 |
2010年 | 75篇 |
2009年 | 83篇 |
2008年 | 113篇 |
2007年 | 138篇 |
2006年 | 128篇 |
2005年 | 132篇 |
2004年 | 102篇 |
2003年 | 85篇 |
2002年 | 88篇 |
2001年 | 92篇 |
2000年 | 87篇 |
1999年 | 96篇 |
1998年 | 50篇 |
1997年 | 57篇 |
1996年 | 56篇 |
1995年 | 42篇 |
1994年 | 36篇 |
1993年 | 40篇 |
1992年 | 74篇 |
1991年 | 58篇 |
1990年 | 82篇 |
1989年 | 71篇 |
1988年 | 73篇 |
1987年 | 74篇 |
1986年 | 71篇 |
1985年 | 62篇 |
1984年 | 46篇 |
1983年 | 44篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1979年 | 46篇 |
1978年 | 32篇 |
1977年 | 31篇 |
1975年 | 32篇 |
1974年 | 35篇 |
1973年 | 55篇 |
1972年 | 35篇 |
1971年 | 29篇 |
1970年 | 28篇 |
1967年 | 33篇 |
排序方式: 共有3543条查询结果,搜索用时 437 毫秒
101.
B. K. A. Thomson M. A. J. Moser C. Marek M. Bloch C. Weernink A. Shoker P. P. Luke 《Clinical transplantation》2013,27(6):E709-E714
Delayed graft function (DGF) in kidney transplantation affects adverse outcomes. It remains unclear whether the post‐transplant dialysis modality alters perioperative or long‐term graft outcomes. We performed a retrospective observational quality initiative at two Canadian renal transplant centers, in which DGF occurred in the recipient, necessitating one of peritoneal dialysis (PD) or hemodialysis (HD). There was no difference in baseline factors between patients with post‐transplant PD (n = 14) or HD (n = 63). The use of PD was associated with an increased risk of wound infection/leakage (PD 5/14 vs. HD 6/63, p = 0.024), shorter length of hospitalization (13.7 vs. 18.7 d, p = 0.009) and time requiring dialysis post‐operatively (6.5 vs 11.0 d, p = 0.043). There were no differences in readmission to hospital within 6 months (4/14 vs. 23/63, p = 0.759), graft loss (0/14 vs. 2/63, p = 1.000) or acute rejection episodes (1/14 vs. 4/63, p = 1.000) at one yr, and GFR did not differ between the PD or HD groups at 30 d (35.7 vs. 33.8 mL/min/m2, p = 0.731), six months (46.9 vs. 45.5 mL/min/m2, p = 0.835) or one yr (46.6 vs. 44.5 mL/min/m2, p = 0.746). Further research is needed to determine which transplant patients are most appropriate to undergo PD catheter removal at the time of transplantation. 相似文献
102.
Brian Reichow Fred R. Volkmar Michael H. Bloch 《Journal of autism and developmental disorders》2013,43(10):2435-2441
Many children with pervasive developmental disorders (PDD) exhibit behaviors and symptoms of attention-deficit/hyperactivity disorder (ADHD). We sought to determine the relative efficacy of medications for treating ADHD symptoms in children with PDD by identifying all double-blind, randomized, placebo-controlled trials examining the efficacy of medications for treating ADHD symptoms in children with PDD. We located seven trials involving 225 children. A random effects meta-analysis of four methylphenidate trials showed methylphenidate to be effective for treating ADHD symptoms in children with PDD (ES = .67). Several adverse events were greater for children were taking methylphenidate compared to placebo. An individual trial of clonidine and two trials of atomoxetine suggest these agents may also be effective in treating ADHD symptoms in children with PDD. 相似文献
103.
The influences of exercise on cytokine response, health-related quality of life (HR-QoL), and fatigue are important aspects of MS rehabilitation. Physical exercises performed within these programs are often practiced in water, but the effects of immersion have not been investigated. To investigate the influences of short-term immune responses and cardiorespiratory fitness on HR-QoL and fatigue during 3 weeks endurance training conducted on a cycle-ergometer or an aquatic-bike. Randomized controlled clinical trial in 60 MS patients. HR-QoL, fatigue, cardiorespiratory fitness, and short-term immune changes (serum concentrations in response to cardiopulmonary exercise test) of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), interleukin-6, and the soluble receptor of IL-6 (sIL-6R) were determined at the beginning and end of 3 weeks of training intervention. Subjects performed daily 30 min training at 60 % of their VO2peak. SF-36 total (p = 0.031), physical (p = 0.004), and mental health (p = 0.057) scores show time effects within both groups. Between-group effects were shown for FSMC total (p = 0.040) and motor function score (p = 0.041). MFIS physical fatigue showed time effects (p = 0.008) for both groups. Linear regression models showed relationships between short-term immune responses and cardiorespiratory fitness with HR-QoL and fatigue after the intervention. This study indicates beneficial effects of endurance training independent of the training setting. Short-term immune adaptations and cardiorespiratory fitness have the potential to influence HR-QoL and fatigue in persons with MS. The specific immune responses of immersion to exercise need further clarification. 相似文献
104.
105.
Emily Behling MD Candidate Luis C. Farhat MD Angeli Landeros-Weisenberger MD Michael H. Bloch MD MS 《Movement disorders》2022,37(4):684-693
Vesicular monoamine transporter type 2 (VMAT2) inhibitors may be an effective therapy for chronic tic disorders (CTD), including Tourette syndrome (TS), but there has not been a meta-analysis compiling available evidence from randomized controlled trials (RCTs). We performed a systematic review and meta-analysis to evaluate the efficacy, acceptability, and tolerability of VMAT2 inhibitors for CTD/TS. PubMed, CENTRAL, and Embase were searched for double-blinded RCTs of VMAT2 inhibitors versus placebo for the treatment of CTD/TS. Change in tic severity measured by the Yale Global Tic Severity Scale (efficacy) and rates of discontinuation attributed to adverse effects (tolerability) or all causes (acceptability) were extracted closest to 12 weeks. Mean difference (MD) and odds ratio (OR) were the effect size indexes for efficacy and acceptability/tolerability, respectively. Data were pooled through random-effects meta-analysis weighted by inverse variance. Five RCTs involving eight comparisons were included. Meta-analysis found a nonsignificant effect on efficacy (k = 8; N = 583; MD = −0.71; 95% confidence interval [CI], −1.93 to 0.50; P = 0.24), and there was certainty that the true effect is nonclinically meaningful (high quality of evidence). Meta-analysis found decreased tolerability (k = 7; N = 626; OR = 2.67; 95% CI, 1.21–5.92; P = 0.01) and decreased acceptability (k = 8; N = 626; OR = 1.90; 95% CI, 1.14–3.18; P = 0.01), although those comparisons were limited because of the relatively small number of events across trials. Meta-analyses did not support the efficacy of VMAT2 inhibitors in the short-term treatment of tic disorders and suggested no clinically meaningful effect of these agents on tic symptoms. © 2022 International Parkinson and Movement Disorder Society 相似文献
106.
Current protocols for the measurement of proton dose focus on measurements under reference conditions; methods for measuring dose under patient-specific conditions have not been standardized. In particular, it is unclear whether dose in patient-specific fields can be determined more reliably with or without the presence of the patient-specific range compensator. The aim of this study was to quantitatively assess the reliability of two methods for measuring dose per monitor unit (DIMU) values for small-field treatment portals: one with the range compensator and one without the range compensator. A Monte Carlo model of the Proton Therapy Center-Houston double-scattering nozzle was created, and estimates of D/MU values were obtained from 14 simulated treatments of a simple geometric patient model. Field-specific D/MU calibration measurements were simulated with a dosimeter in a water phantom with and without the range compensator. D/MU values from the simulated calibration measurements were compared with D/MU values from the corresponding treatment simulation in the patient model. To evaluate the reliability of the calibration measurements, six metrics and four figures of merit were defined to characterize accuracy, uncertainty, the standard deviations of accuracy and uncertainty, worst agreement, and maximum uncertainty. Measuring D/MU without the range compensator provided superior results for five of the six metrics and for all four figures of merit. The two techniques yielded different results primarily because of high-dose gradient regions introduced into the water phantom when the range compensator was present. Estimated uncertainties (approximately 1 mm) in the position of the dosimeter in these regions resulted in large uncertainties and high variability in D/MU values. When the range compensator was absent, these gradients were minimized and D/MU values were less sensitive to dosimeter positioning errors. We conclude that measuring D/MU without the range compensator present provides more reliable results than measuring it with the range compensator in place. 相似文献
107.
Increased Ca2+ sensitivity and protein expression of SERCA 2a in situations of chronic β3-adrenoceptor deficiency 总被引:1,自引:1,他引:0
Ziskoven C Grafweg S Bölck B Wiesner RJ Jimenez M Giacobino JP Bloch W Schwinger RH Brixius K 《Pflügers Archiv : European journal of physiology》2007,453(4):443-453
This study investigated the influence of chronic β3-adrenoceptor deficiency on myocardial function. Therefore, we investigated Ca2+-regulatory proteins, SERCA 2a activity, and myofibrillar and mitochondrial function in hearts of wild-type (WT, n=7) and β3-adrenoceptor knockout mice (β3-KNO, n=7). Morphometric heart analysis showed no difference between WT and β3-KNO. No alterations were observed for the protein expression of the ryanodine receptor or phospholamban. However, in β3-KNO mice, protein expression of SERCA 2a and phospholamban phosphorylation were significantly increased. These changes were
accompanied by an increased SERCA 2a activity in β3-KNO. Alterations in phospholamban phosphorylation were independent of alterations in β1/β2-adrenoceptor distribution and protein expression of G proteins in β3-KNO. Measurement of myofibrillar Ca2+ sensitivity showed no difference in the Ca2+/force relation for WT and β3-KNO. The same seems to hold true for mitochondrial function since the protein expressions of cytochrome c, uncoupling protein 3 and cytochrome c oxidase subunit IV were similar in WT and β3-KNO. The conclusion is that depression of β3-adrenergic stimulation may modulate the protein expression of SERCA 2a and phospholamban phosphorylation, thereby improving
sarcoplasmic reticulum Ca2+ uptake. Thus, β3-adrenergic depression may be a therapeutic aim in situations of impaired SERCA 2a activity, e.g. for the treatment of heart
failure. 相似文献
108.
Anne Breaks Christina Smith Steven Bloch Sally Morgan 《Journal of human nutrition and dietetics》2018,31(5):634-646
Background
The present review aimed to identify what is known about the use of blended diets in gastrostomy fed children and young people (i.e. children and young people refers to those who are aged up to 25 years with special educational needs or a disability in accordance with Part 3 of the Children and Family Act 2014; within the review, the word children is used for simplicity but encompasses young people too) and to identify gaps in the literature on this topic to inform future research and policy.Methods
A scoping review methodology was used searching the online databases PUBMED , PsychINFO , CINAHL , SCOPUS and AMED , EMBASE for articles that addressed issues pertaining to blended diets. The review identified a broad range of literature, regardless of study design, and described and evaluated the quality, range and nature of research activity related to the use of blenderised diets.Results
Forty‐three studies were included in the review. The studies focused on nutrition, equipment, the views of carers and patients, and the views of professionals. Several studies described the lack of evidence regarding pros and cons of blended diets and highlighted the need for further research into the field.Conclusions
There were gaps in the evidence base regarding the impact of blended diets on the health and well‐being of the children who receive them and upon the carers who feed the children. The nutritional impact of blended diets is not fully understood and the knowledge and views of professionals involved in the care of those receiving blended diets varies.109.
Use of complementary and alternative medicine has increased over the past decade. A variety of studies have suggested that this use is greater in persons with symptoms or diagnoses of anxiety and depression. Data support the effectiveness of some popular herbal remedies and dietary supplements; in some of these products, particularly kava, the potential for benefit seems greater than that for harm with short-term use in patients with mild to moderate anxiety. Inositol has been found to have modest effects in patients with panic disorder or obsessive-compulsive disorder. Physicians should not encourage the use of St. John's wort, valerian, Sympathyl, or passionflower for the treatment of anxiety based on small or inconsistent effects in small studies. Although the evidence varies depending on the supplement and the anxiety disorder, physicians can collaborate with patients in developing dietary supplement strategies that minimize risks and maximize benefits. 相似文献
110.
Sylwia Bloch Bo?ena Nejman-Faleńczyk Gracja Topka Aleksandra Dydecka Katarzyna Licznerska Magdalena Narajczyk Agnieszka Necel Alicja W?grzyn Grzegorz W?grzyn 《Toxins》2015,7(9):3727-3739
Shiga toxin-converting bacteriophages (Stx phages) are present as prophages in Shiga toxin-producing Escherichia coli (STEC) strains. Theses phages can be transmitted to previously non-pathogenic E. coli cells making them potential producers of Shiga toxins, as they bear genes for these toxins in their genomes. Therefore, sensitivity of Stx phage virions to various conditions is important in both natural processes of spreading of these viruses and potential prophylactic control of appearance of novel pathogenic E. coli strains. In this report we provide evidence that virions of Stx phages are significantly more sensitive to UV irradiation than bacteriophage λ. Following UV irradiation of Stx virions at the dose of 50 J/m2, their infectivity dropped by 1–3 log10, depending on the kind of phage. Under these conditions, a considerable release of phage DNA from virions was observed, and electron microscopy analyses indicated a large proportion of partially damaged virions. Infection of E. coli cells with UV-irradiated Stx phages resulted in significantly decreased levels of expression of N and cro genes, crucial for lytic development. We conclude that inactivation of Stx virions caused by relatively low dose of UV light is due to damage of capsids that prevents effective infection of the host cells. 相似文献