全文获取类型
收费全文 | 5935篇 |
免费 | 313篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 160篇 |
妇产科学 | 100篇 |
基础医学 | 875篇 |
口腔科学 | 491篇 |
临床医学 | 374篇 |
内科学 | 1293篇 |
皮肤病学 | 146篇 |
神经病学 | 501篇 |
特种医学 | 120篇 |
外科学 | 714篇 |
综合类 | 32篇 |
预防医学 | 540篇 |
眼科学 | 103篇 |
药学 | 411篇 |
中国医学 | 24篇 |
肿瘤学 | 317篇 |
出版年
2023年 | 52篇 |
2022年 | 100篇 |
2021年 | 173篇 |
2020年 | 132篇 |
2019年 | 177篇 |
2018年 | 168篇 |
2017年 | 145篇 |
2016年 | 146篇 |
2015年 | 202篇 |
2014年 | 245篇 |
2013年 | 314篇 |
2012年 | 462篇 |
2011年 | 520篇 |
2010年 | 323篇 |
2009年 | 255篇 |
2008年 | 417篇 |
2007年 | 374篇 |
2006年 | 293篇 |
2005年 | 287篇 |
2004年 | 268篇 |
2003年 | 216篇 |
2002年 | 174篇 |
2001年 | 58篇 |
2000年 | 62篇 |
1999年 | 55篇 |
1998年 | 36篇 |
1997年 | 26篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 16篇 |
1993年 | 18篇 |
1992年 | 29篇 |
1991年 | 24篇 |
1990年 | 35篇 |
1989年 | 28篇 |
1988年 | 33篇 |
1987年 | 31篇 |
1986年 | 25篇 |
1985年 | 22篇 |
1984年 | 26篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 30篇 |
1977年 | 22篇 |
1974年 | 16篇 |
1973年 | 14篇 |
1971年 | 13篇 |
1969年 | 13篇 |
排序方式: 共有6272条查询结果,搜索用时 0 毫秒
1.
P Pencharz J Beesley P Sauer J Van Aerde U Canagarayar J Renner M McVey D Wesson P Swyer 《The American journal of clinical nutrition》1989,50(6):1395-1400
The effects of nonprotein energy source (ie, glucose only vs glucose and lipid) on nitrogen retention and total-body protein turnover were studied in 20 parenterally fed newborn infants. All infants received approximately 3 g amino acids and 80-90 kcal.kg body wt.d. Total-body protein synthesis was estimated by using three constant-infusion, end-product methods: enrichment of urinary urea and ammonia in response to a [15N]glycine label and exhaled carbon dioxide enrichment in response to a [1-13C]leucine label. No differences were seen in nitrogen retention between the two energy sources. The estimate of total-body protein turnover obtained from the 13C label was similar to that obtained with the [15N]urea label. No differences in turnover rates were observed between the two diet groups. Use of the glucose-plus-lipid fuel system enhanced energy storage and the reutilization of amino acid for protein synthesis. 相似文献
2.
Background
Due to marginalization, trafficking violence, conflicts with the police and organic and social psychological problems associated with the drug, crack is one of the most devastating drugs currently in use. However, there is evidence that some users manage to stay alive and active while using crack cocaine for many years, despite the numerous adversities and risks involved with this behavior. In this context, the aim of the present study was to identify the strategies and tactics developed by crack users to deal with the risks associated with the culture of use by examining the survival strategies employed by long-term users. 相似文献3.
Otavio A C Clark Gary H Lyman Aldemar A Castro Luciana G O Clark Benjamin Djulbegovic 《Journal of clinical oncology》2005,23(18):4198-4214
PURPOSE: Current treatment for febrile neutropenia (FN) includes hospitalization for evaluation, empiric broad-spectrum antibiotics, and other supportive care. Clinical trials have reported conflicting results when studying whether the colony-stimulating factors (CSFs) improve outcomes in patients with FN. This Cochrane Collaboration review was undertaken to further evaluate the safety and efficacy of the CSFs in patients with FN. METHODS: An exhaustive literature search was undertaken including major electronic databases (CANCERLIT, EMBASE, LILACS, MEDLINE, SCI, and the Cochrane Controlled Trials Register). All randomized controlled trials that compare CSFs plus antibiotics versus antibiotics alone for the treatment of established FN in adults and children were sought. A meta-analysis of the selected studies was performed. RESULTS: More than 8,000 references were screened, with 13 studies meeting eligibility criteria for inclusion. The overall mortality was not influenced significantly by the use of CSF (odds ratio [OR] = 0.68; 95% CI, 0.43 to 1.08; P = .1). A marginally significant result was obtained for the use of CSF in reducing infection-related mortality (OR = 0.51; 95% CI, 0.26 to 1.00; P = .05). Patients treated with CSFs had a shorter length of hospitalization (hazard ratio [HR] = 0.63; 95% CI, 0.49 to 0.82; P = .0006) and a shorter time to neutrophil recovery (HR = 0.32; 95% CI, 0.23 to 0.46; P < .00001). CONCLUSION: The use of the CSFs in patients with established FN caused by cancer chemotherapy reduces the amount of time spent in hospital and the neutrophil recovery period. The possible influence of the CSFs on infection-related mortality requires further investigation. 相似文献
4.
5.
Bruno Biancosino Denis Rocchi Silvia Donà Vasiliki Kotrotsiou Luciana Marmai Luigi Grassi 《European psychiatry》2006,21(7):460-462
Insomnia in psychiatric patients is frequently underestimated in clinical practice. Usually drugs are prescribed for the treatment of this disorder but non-pharmacological intervention can be successfully used. The present study aimed at evaluating the efficacy of a two-session psychoeducational intervention in improving persistent non-organic insomnia and reducing the administration of PRN therapy in severely mentally ill patients. A pre-post study was performed on 36 psychiatric patients admitted to a residential psychiatric unit. The Nocturnal Sleep Onset Scale (NSOS) and Daytime Sleepiness Scale (DSS), the sleep onset latency, the time awake after sleep onset and the numbers of awakenings were gathered 2 weeks before the intervention (T0), immediately prior the intervention (T1), 2 weeks after the last session of the intervention (T2) and a 3-month follow-up (T3). The total number of administrations of PRN therapy from T0 to T1 and from T1 to T2 were also examined. A significant reduction was shown on the NSOS, the sleep onset latency and in the time awake after sleep onset from T1 to T2 and from T1 to T3, while no significant difference was found between T0 and T1. A significant decrease on the mean number of administrations of PRN therapy was also found between 15 days before the intervention (T0-T1) and 15 days after intervention (T1-T2). The initial results of this study seems to suggest the possible efficacy of a short-term psychoeducational intervention on improving persistent non-organic insomnia in severely mentally ill patients. Further control studies are necessary to confirm these findings. 相似文献
6.
This case report represents the first well-documented case of aberrant internal carotid arteries in both middle ears. CT and DSA can establish the diagnosis before surgical intervention. Aberrant internal carotid artery represents a rare finding in the differential diagnosis of middle ear masses. Most patients manifest either vertigo, tinnitus, or a variable hearing loss. Clinical findings include a red or blue mass behind the eardrum that may or may not be pulsatile. The otolaryngologist should be aware that this potential landmine may be obscured by serous otitis media. Once suspected, the mass should be evaluated by radiographic studies before surgical intervention. 相似文献
7.
8.
Luciana Dias de Oliveira Elsa Regina Justo Giugliani Lílian Córdova do Espírito Santo Maristela Cavalheiro Tamborindeguy Fran?a Enilda Maria Lara Weigert Celina Valderez Feijó Kohler Ana Lúcia de Lourenzi Bonilha 《Journal of human lactation》2006,22(3):315-321
This randomized clinical trial compared frequencies of exclusive breastfeeding and lactation-related problems during the first 30 days among 74 mothers who received a 30-minute counseling session on breastfeeding technique in the maternity ward, and 137 controls. The frequency of exclusive breastfeeding among mothers who had received intervention was similar to controls by 7 days (79.7% vs 82.5%, respectively) and 30 days (60.8% vs 53.3%). There was no difference between groups in the frequency of sore nipples at 7 and 30 days, in breast engorgement and mastitis, and in the quality of breastfeeding technique at 30 days. Therefore, a single intervention at maternity was not sufficient to improve breastfeeding technique, increase exclusive breastfeeding rates, and reduce the incidence of breastfeeding problems during the first month. 相似文献
9.
10.
M A Mauro L A Parker W S Hartley J B Renner P M Mauro 《AJR. American journal of roentgenology》1987,149(5):925-927
Epidermolysis bullosa is a group of dermatologic disorders with varied inheritance patterns having the common manifestation of blister or bulla formation after minor trauma. Sixteen patients with the disease had the following radiographic manifestations: esophageal stricture (16), fecal impaction (six), vaginal stenosis (one), epithelial bridging and fusion of the digits (six), and aspiration changes in the lungs (two). Esophageal strictures involved the pharynx or cervical esophagus in eight cases and were multiple in five; they ranged in length from 2 mm to 15 cm and tended to progress over time. The findings of esophageal stricture, particularly when multiple and involving the proximal esophagus, and/or the presence of distal phalangeal atrophy with soft-tissue webbing suggest the diagnosis of epidermolysis bullosa. 相似文献