全文获取类型
收费全文 | 27200篇 |
免费 | 1565篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 297篇 |
儿科学 | 831篇 |
妇产科学 | 730篇 |
基础医学 | 3372篇 |
口腔科学 | 312篇 |
临床医学 | 3881篇 |
内科学 | 4845篇 |
皮肤病学 | 408篇 |
神经病学 | 2522篇 |
特种医学 | 584篇 |
外科学 | 2998篇 |
综合类 | 266篇 |
现状与发展 | 1篇 |
一般理论 | 50篇 |
预防医学 | 3431篇 |
眼科学 | 388篇 |
药学 | 1839篇 |
3篇 | |
中国医学 | 29篇 |
肿瘤学 | 2033篇 |
出版年
2024年 | 131篇 |
2023年 | 325篇 |
2022年 | 430篇 |
2021年 | 914篇 |
2020年 | 613篇 |
2019年 | 944篇 |
2018年 | 973篇 |
2017年 | 723篇 |
2016年 | 720篇 |
2015年 | 839篇 |
2014年 | 1107篇 |
2013年 | 1513篇 |
2012年 | 2210篇 |
2011年 | 2159篇 |
2010年 | 1198篇 |
2009年 | 973篇 |
2008年 | 1719篇 |
2007年 | 1745篇 |
2006年 | 1597篇 |
2005年 | 1522篇 |
2004年 | 1340篇 |
2003年 | 1174篇 |
2002年 | 1074篇 |
2001年 | 261篇 |
2000年 | 206篇 |
1999年 | 212篇 |
1998年 | 218篇 |
1997年 | 153篇 |
1996年 | 151篇 |
1995年 | 104篇 |
1994年 | 80篇 |
1993年 | 95篇 |
1992年 | 115篇 |
1991年 | 104篇 |
1990年 | 105篇 |
1989年 | 83篇 |
1988年 | 94篇 |
1987年 | 68篇 |
1986年 | 66篇 |
1985年 | 72篇 |
1984年 | 66篇 |
1983年 | 39篇 |
1982年 | 42篇 |
1981年 | 31篇 |
1979年 | 47篇 |
1975年 | 32篇 |
1973年 | 34篇 |
1972年 | 26篇 |
1971年 | 26篇 |
1970年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Ahmed J Marucci D Cochrane L Heywood RL Wyatt ME Leighton SE 《The Journal of craniofacial surgery》2008,19(3):659-663
Syndromic craniosynostosis is known to be associated with obstructive sleep apnea (OSA), which can often present in infancy. Although multifactorial, a predominant contributing factor is midface hypoplasia. Nasal continuous positive airway pressure has proven to be an effective treatment modality but may be poorly tolerated in certain cases. This study looks at the effectiveness of bypassing midface obstruction with a nasopharyngeal airway (NPA). Twenty-seven children with syndromic craniosynostosis with confirmed moderate to severe OSA were initially treated with an NPA. The mean age of NPA insertion was 12.3 months (range, 0.5-48 mo). Seventeen had severe OSA, and 10 had moderate OSA preinsertion. Post-NPA insertion, 26 of 27 children (96%) demonstrated an improvement in sleep severity scores, resulting in 3 with moderate OSA and 24 with mild OSA. There was a significant improvement in mean oxygen saturation, mean number of saturation dips greater than 4% per hour, percentage time spent less than 90% SpO2, and number of pulse rate rises per hour. There were no significant differences in mean pulse rate. The NPA was well tolerated by this patient group, with 24 of 26 children retaining it for at least 6 weeks. We believe that an NPA is therefore an effective first-line treatment modality in the management of OSA in children with syndromic craniosynostosis. It is well tolerated by the patient and may obviate the need for continuous positive airway pressure or tracheostomy. 相似文献
22.
Carrie L Heike Anthony M Avellino Sohail K Mirza Yemiserach Kifle Jonathan Perkins Raymond Sze Mark Egbert Anne V Hing 《The Cleft palate-craniofacial journal》2007,44(3):340-346
The 22q11.2 deletion syndrome is characterized by wide phenotypic variability, frequently involving characteristic craniofacial features, cardiac malformations, and learning difficulties. Skeletal anomalies are also common and include an obtuse angle of the cranial base, retrognathia, and cervical spine abnormalities. Despite these anomalies, sleep-disturbed breathing is not reported frequently in patients with 22q11.2 deletion syndrome. We describe a patient with an obstructive sleep disturbance that was successfully treated with a tonsillectomy followed by mandibular distraction osteogenesis. She also had central sleep apnea, initially attributed to spinal cord impingement from cervical instability. Posterior cervical fusion was associated with a decrease in the number of central apneic events. 相似文献
23.
24.
Michelle C Sunico Koichi Shinkai Vicente O Medina Manabu Shirono Norihiro Tanaka Yoshiroh Katoh 《Dental materials》2002,18(7):535-542
OBJECTIVES: To determine the effect of different combinations of surface conditioning (DeTrey Conditioner 36, NRC, no etching) and restorative materials (Dyract AP, Spectrum TPH) on the shear bond strength of Prime and Bond NT to enamel and dentin, and to characterize the resin-dentin interface produced by these combinations. METHODS: Shear bond strength was tested on 30 enamel and 30 dentin flat labial surfaces of extracted bovine teeth. The enamel and dentin specimens were randomly assigned to six groups of five teeth each and treated using different combinations of surface conditioners and restorative materials with Prime and Bond NT. Scanning electron microscope (SEM) observation of argon-ion-etched specimens was done to evaluate the resin-dentin interface. RESULTS: The type of surface conditioning and restorative material had significant effects on dentin bond strengths. Etching the dentin prior to application of Prime and Bond NT significantly increased bond strength and caused formation of a hybrid layer for Spectrum TPH. For Dyract AP, dentin etching generally did not improve bond strength despite the formation of a hybrid layer. On enamel, Prime and Bond NT had consistently high bond strengths on etched specimens. SIGNIFICANCE: The results showed that Dyract AP and Spectrum TPH, when used with Prime and Bond NT have different bonding mechanisms and the effect of surface conditioning on their shear bond strength differs. Clinicians should be aware of these effects in order to optimize bonding. 相似文献
25.
King NM Tay FR Pashley DH Hashimoto M Ito S Brackett WW García-Godoy F Sunico M 《American journal of dentistry》2005,18(2):126-134
PURPOSE: One-step self-etch adhesives have restricted use due to their acid-base incompatibility with autocured composites and their behavior as permeable membranes after polymerization. This study examined the feasibility of their conversion to two-step self-etch adhesives via the adjunctive use of a non-solvented, relatively hydrophobic resin coating. METHODS: iBond, Xeno III and Adper Prompt were used either in multiple coats, or in a single coat followed by the use of a layer of Scotchbond Multi-Purpose Plus bond resin for coupling to light- and auto-cured composites. Four types of experiments were performed. Bonded specimens were examined with TEM after immersion in an ammoniacal silver nitrate tracer. Fluid flow measurements of iBond were conducted using the two application protocols to compare the permeability of the bonded dentin with the original smear layer. Permeability of vital dentin bonded with both application protocols were compared for the transudation of dentin fluid across the bonded dentin. Microtensile bond strengths of dentin bonded with the two protocols were examined for their compatibility with an auto-cured composite. RESULTS: The results of the four experiments were complementary. iBond and Xeno III exhibited "apparent incompatibility" to auto-cured composites that resulted from their inherent permeability. This was confirmed by the presence of dentin fluid transudate on the adhesive surfaces when they were bonded to vital dentin. Conversely, Adper Prompt exhibited "true incompatibility" to auto-cured composites that was caused by adverse acid-base interaction, masking the inherent permeability of this adhesive. "True" and "apparent" incompatibility issues were eliminated upon their conversion to two-step self-etch adhesives. 相似文献
26.
27.
Michelle N. Valadão Érica R. Coimbra Michele C. Landemberger Tonicarlo R. Velasco Vera C. Terra Lauro Wichert-Ana Veriano Alexandre Jr. David Araújo Jr. Ricardo Guarnieri Vilma R. Martins Antônio Carlos Santos Américo C. Sakamoto Roger Walz 《Neurological sciences》2014,35(2):239-244
The cellular prion protein, encoded by Prnp gene, is involved in neuroprotection, neuroplasticity and neurodevelopment. The variant allele Valine at codon 129 of the Prnp was associated with decreased brain volume in healthy volunteers and schizophrenic patients. We investigate the association between the cerebellum volume and the presence of variant allele Valine at codon 129 of the Prnp gene in patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). The Prnp coding sequence was determined in 41 refractory MTLE-HS patients. The cerebellum volume corrected by the intracranial volume of patients with the normal Prnp genotypes was compared with that of patients presenting the variant alleles at codon 129. Twenty patients showed the Met129Met genotype, 16 showed Met129Val, and 5 had Val129Val. There were no association among clinical, demographic, electrophysiological, antiepileptic drugs used, and the presence of the Prnp variant alleles. The presence of Prnp variant allele at codon 129 was not associated with the analyzed cerebellum volume. Prnp variant alleles at codon 129 are not associated with cerebellum volume in patients with refractory MTLE-HS. 相似文献
28.
29.
Michelle Bilbao Alison Spaniol Jeremy Bearss Chris Schellhase Stuart Shippey Matthew Aungst 《International urogynecology journal》2014,25(1):97-101
Introduction and hypothesis
The purpose of this study was to histologically chronicle wound healing following cystotomy repair using a small animal model.Methods
Thirty female Sprague–Dawley rats were included in this study. Twenty-eight rats underwent a vertical cystotomy in the bladder dome, which was repaired in a single continuous fashion. Two rats served as histological controls. Following cystotomy repair, groups of three to four rats were studied at single day intervals for 4 days, then at 2-day intervals until 10 days post-repair. The animal bladders were harvested and examined for inflammation, scar formation, and bladder healing.Results
Thirty rat bladders were histologically examined. An inflammatory wound phase was observed during the first 4 days after wounding. Transition from acute to chronic inflammation was observed at day 2 with chronic inflammation persisting through day 10. Inflammation severity peaked 4 days post-wounding without regression through day 10. Evidence of proliferative phase wound healing was first observed 4 days post-wounding.Conclusion
Early increases in wound healing are due to inflammatory events such as fibrin plugging of the wound. Later developments after day 4 are due to wound proliferation, collagen deposition, and re-epithelialization. Additionally, wound healing in the rat bladder is observed on a continuum and not necessarily in discrete stages observed on precisely the same postoperative day in each animal. 相似文献30.
Rolands G Aravindan Catherine B Kirn-Safran Michelle A Smith Patricia A Martin-DeLeon 《Asian journal of andrology》2014,16(6):925-926
Dear Editor,
We present here the first report linking a specific gene, ribosomal protein L29 (Rp129), also known as Hip (heparin/heparan sulfate interacting protein), to the mammalian sperm flagellar morphological anomaly termed the "dag" defect. In addition, we show that loss of Rp/29 invariably results in low sperm motility with infertility accompanying this abnormality. 相似文献
We present here the first report linking a specific gene, ribosomal protein L29 (Rp129), also known as Hip (heparin/heparan sulfate interacting protein), to the mammalian sperm flagellar morphological anomaly termed the "dag" defect. In addition, we show that loss of Rp/29 invariably results in low sperm motility with infertility accompanying this abnormality. 相似文献