全文获取类型
收费全文 | 3257篇 |
免费 | 222篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 126篇 |
妇产科学 | 94篇 |
基础医学 | 527篇 |
口腔科学 | 36篇 |
临床医学 | 270篇 |
内科学 | 778篇 |
皮肤病学 | 80篇 |
神经病学 | 394篇 |
特种医学 | 86篇 |
外科学 | 318篇 |
综合类 | 13篇 |
一般理论 | 1篇 |
预防医学 | 209篇 |
眼科学 | 24篇 |
药学 | 224篇 |
中国医学 | 5篇 |
肿瘤学 | 290篇 |
出版年
2024年 | 5篇 |
2023年 | 44篇 |
2022年 | 110篇 |
2021年 | 144篇 |
2020年 | 100篇 |
2019年 | 123篇 |
2018年 | 112篇 |
2017年 | 96篇 |
2016年 | 106篇 |
2015年 | 122篇 |
2014年 | 166篇 |
2013年 | 186篇 |
2012年 | 300篇 |
2011年 | 293篇 |
2010年 | 148篇 |
2009年 | 136篇 |
2008年 | 249篇 |
2007年 | 203篇 |
2006年 | 167篇 |
2005年 | 183篇 |
2004年 | 133篇 |
2003年 | 117篇 |
2002年 | 78篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 11篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1996年 | 17篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有3495条查询结果,搜索用时 10 毫秒
101.
James T. McKenna Chun Yang Serena Franciosi Stuart Winston Kathleen K. Abarr Matthew S. Rigby Yuchio Yanagawa Robert W. McCarley Ritchie E. Brown 《The Journal of comparative neurology》2013,521(6):1225-1250
The basal forebrain (BF) strongly regulates cortical activation, sleep homeostasis, and attention. Many BF neurons involved in these processes are GABAergic, including a subpopulation of projection neurons containing the calcium‐binding protein, parvalbumin (PV). However, technical difficulties in identification have prevented a precise mapping of the distribution of GABAergic and GABA/PV+ neurons in the mouse or a determination of their intrinsic membrane properties. Here we used mice expressing fluorescent proteins in GABAergic (GAD67‐GFP knock‐in mice) or PV+ neurons (PV‐Tomato mice) to study these neurons. Immunohistochemical staining for GABA in GAD67‐GFP mice confirmed that GFP selectively labeled BF GABAergic neurons. GFP+ neurons and fibers were distributed throughout the BF, with the highest density in the magnocellular preoptic area (MCPO). Immunohistochemistry for PV indicated that the majority of PV+ neurons in the BF were large (>20 μm) or medium‐sized (15–20 μm) GFP+ neurons. Most medium and large‐sized BF GFP+ neurons, including those retrogradely labeled from the neocortex, were fast‐firing and spontaneously active in vitro. They exhibited prominent hyperpolarization‐activated inward currents and subthreshold “spikelets,” suggestive of electrical coupling. PV+ neurons recorded in PV‐Tomato mice had similar properties but had significantly narrower action potentials and a higher maximal firing frequency. Another population of smaller GFP+ neurons had properties similar to striatal projection neurons. The fast firing and electrical coupling of BF GABA/PV+ neurons, together with their projections to cortical interneurons and the thalamic reticular nucleus, suggest a strong and synchronous control of the neocortical fast rhythms typical of wakefulness and REM sleep. J. Comp. Neurol., 521:1225–1250, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
102.
Damiano Pasqualini Loredana Bergandi Luigi Palumbo Alberto Borraccino Valentina Dambra Mario Alovisi Giuseppe Migliaretti Gaetana Ferraro Dario Ghigo Serena Bergerone Nicola Scotti Mario Aimetti Elio Berutti 《Journal of endodontics》2012
Introduction
There is evidence to suggest that an association exists between oral infections and coronary heart disease (CHD). Subjects presenting lesions of endodontic origin (LEOs) or pulpal inflammation had an increased risk of developing CHD. However, findings concerning systemic manifestations of apical periodontitis (AP) remain controversial. An association between CD14 gene polymorphisms and atherosclerosis-associated diseases has been shown, but there are no data regarding an association between CD14 polymorphism and AP. This study evaluated associations between clinical oral health status, CD14 polymorphisms, and CHD.Methods
A case-controlled clinical trial was designed to compare middle-aged adults with acute myocardial infarction or unstable angina (n = 51) within 12 months of the acute event defined as first manifestation with healthy controls (n = 49). Participants were matched for age, sex, and socioeconomic status. Indicators of oral disease and compliance were evaluated. CD14 polymorphisms were analyzed by restriction fragment length polymorphism–polymerase chain reaction.Results
CHD subjects had a higher prevalence of oral diseases and lower compliance to oral preventive strategies than healthy controls. Multivariate analysis showed a positive association between missing teeth (odds ratio [OR] = 1.37; 95% confidence interval [CI], 1.02–1.85), the number of LEOs (OR = 4.37; 95% CI, 1.69–11.28), chronic periodontitis (OR = 5.87; 95% CI, 1.17–29.4), and CHD. No statistically significant association emerged between the CD14 C(−260)T and the CD14 C(−159)T polymorphism, endodontic or periodontal disease, and CHD.Conclusions
Chronic oral diseases may increase the risk of CHD and may be an unconventional risk factor for CHD. 相似文献103.
104.
105.
De Michele Giovanna Galatolo Daniele Galosi Serena Mignarri Andrea Silvestri Gabriella Casali Carlo Leuzzi Vincenzo Ricca Ivana Barghigiani Melissa Tessa Alessandra Cioffi Ettore Caputi Caterina Riso Vittorio Dotti Maria Teresa Saccà Francesco De Michele Giuseppe Cocozza Sirio Filla Alessandro Santorelli Filippo M. 《Journal of neurology》2022,269(3):1476-1484
Journal of Neurology - Spinocerebellar ataxia type 14 (SCA14) is a dominantly inherited neurological disorder characterized by slowly progressive cerebellar ataxia. SCA14 is caused by mutations in... 相似文献
106.
Margherita Gobbo Giulia Ottaviani Katia Rupel Francesca Ciriello Aulo Beorchia Roberto Di Lenarda Serena Zacchigna Matteo Biasotto 《Lasers in medical science》2016,31(3):471-479
Oral mucositis (OM) and radiodermatitis (RD) are serious side effects of radiotherapy (RT), often leading to its suspension, need for analgesics, and enteral/parenteral nutrition. Laser therapy is becoming a recommended treatment option. This prospective study aimed at demonstrating the beneficial effect of class IV laser therapy (HPLT) on RT-induced OM, an off-label use of HPLT to treat RD in breast cancer patients. Fifty-three cancer patients, during/after RT and/or chemotherapy (CT), affected by OM, were treated with HPLT during four consecutive days (970?±?15 nm, 5 W (50 %), 35–6000 Hz, 240 s). Assessment of OM (Grading Objective Scale, WHO-SCALE), pain (visual analogue scale, VAS), functional ability, subjective parameters, and site/severity of OM were recorded over time. Similarly, 27 breast cancer patients affected by RD were treated by HPLT and monitored over time for grade, discomfort, itching, and bleeding. Progressive improvement of WHO-SCALE from day 7 on, and of VAS from day 2 on (p?<?0.000) was registered. All patients’ functional capacity improved on day 4 (p?<?0.05). All subjective parameters improved on day 14 (p?<?0.001) except for voice, which improved on day 21 (p?<?0.000). Ulcerations’ dimension and erythema’s severity significantly decreased in all sites examined (p?<?0.05). Similarly, HPLT proved to be beneficial in managing RD for all the parameters considered (p?<?0.002). Regardless of OM grade/site and of kind/site of tumor, HPLT proved to be effective in healing OM as well as RD. In both cases, effective treatment can improve life quality through a safe, easy, innovative approach. Therefore, HPLT may become an integral part of everyday practice in the management of RT adverse effects. 相似文献
107.
Valentina Rossi Cinzia Mazzola Lorenzo Leonelli Paolo Gandullia Serena Arrigo Marina Pedemonte Maria Cristina Schiaffino Margherita Mancardi Oliviero Sacco Nicola Massimo Disma Clelia Zanaboni Giovanni Montobbio Arrigo Barabino Girolamo Mattioli 《Pediatric surgery international》2016,32(3):277-283
Background
Fundoplication is considered a mainstay in the treatment of gastro-esophageal reflux. However, the literature reports significant recurrences and limited data on long-term outcome.Aims
To evaluate our long-term outcomes of antireflux surgery in children and to assess the results of redo surgery.Methods
We retrospectively analyzed all patients who underwent Nissen fundoplication in 8 consecutive years. Reiterative surgery was indicated only in case of symptoms and anatomical alterations. A follow-up study was carried out to analyzed outcome and patients’ Visick score assessed parents’ perspective.Results
Overall 162 children were included for 179 procedures in total. Median age at first intervention was 43 months. Comorbidities were 119 (73 %), particularly neurological impairments (73 %). Redo surgery is equal to 14 % (25/179). Comorbidities were risk factors to Nissen failure (p = 0.04), especially children suffering neurological impairment with seizures (p = 0.034). Follow-up datasets were obtained for 111/162 = 69 % (median time: 51 months). Parents’ perspectives were excellent or good in 85 %.Conclusions
A significant positive impact of redo Nissen intervention on the patient’s outcome was highlighted; antireflux surgery is useful and advantageous in children and their caregivers. Children with neurological impairment affected by seizures represent significant risk factors.108.
Defining a new diagnostic assessment parameter for wound care: Elevated protease activity,an indicator of nonhealing,for targeted protease‐modulating treatment 下载免费PDF全文
Thomas E. Serena MD Breda M. Cullen PhD Simon W. Bayliff BSc Molly C. Gibson BSc Marissa J. Carter PhD Lingyun Chen PhD Raphael A. Yaakov MS John Samies MD Matthew Sabo DPM Daniel DeMarco DO Namchi Le MD James Galbraith MD 《Wound repair and regeneration》2016,24(3):589-595
It is widely accepted that elevated protease activity (EPA) in chronic wounds impedes healing. However, little progress has occurred in quantifying the level of protease activity that is detrimental for healing. The aim of this study was to determine the relationship between inflammatory protease activity and wound healing status, and to establish the level of EPA above which human neutrophil‐derived elastase (HNE) and matrix metalloproteases (MMP) activities correlate with nonhealing wounds. Chronic wound swab samples (n = 290) were collected from four wound centers across the USA to measure HNE and MMP activity. Healing status was determined according to percentage reduction in wound area over the previous 2–4 weeks; this was available for 211 wounds. Association between protease activity and nonhealing wounds was determined by receiver operating characteristic analysis (ROC), a statistical technique used for visualizing and analyzing the performance of diagnostic tests. ROC analysis showed that area under the curve (AUC) for HNE were 0.69 for all wounds and 0.78 for wounds with the most reliable wound trajectory information, respectively. For MMP, the corresponding AUC values were 0.70 and 0.82. Analysis suggested that chronic wounds having values of HNE >5 and/or MMP ≥13, should be considered wound healing impaired. EPA is indicative of nonhealing wounds. Use of a diagnostic test to detect EPA in clinical practice could enable clinicians to identify wounds that are nonhealing, thus enabling targeted treatment with protease modulating therapies. 相似文献
109.
110.
Moraxella catarrhalis strain O35E expresses two filamentous hemagglutinin-like proteins that mediate adherence to human epithelial cells 下载免费PDF全文
Two-partner secretion (TPS) systems are a family of proteins being rapidly identified and characterized in a growing number of gram-negative bacteria. TPS systems mediate the secretion of proteins, many involved in virulence traits such as hemolysis, adherence to epithelial cells, inhibition of bacterial growth, and immunomodulation of the host. A TPS system typically consists of a transporter located in the bacterial outer membrane (OM) which is responsible for the recognition and secretion of at least one large exoprotein. Two of the better-characterized TPS systems specify the Bordetella pertussis FHA and Haemophilus influenzae HMW1/HMW2 proteins. We identified three gene products of Moraxella catarrhalis strain O35E that resemble TPS proteins and designated them MhaC (transporter), MhaB1 (exoprotein), and MhaB2 (exoprotein). Western blot analysis using anti-MhaC, or antibodies reacting to both MhaB1 and MhaB2 (MhaB-reactive), revealed that these antigens are expressed in the OM of 63% of isolates tested. Mutations in the mhaC gene specifying the putative transporter of the M. catarrhalis wild-type strains O35E, O12E, and McGHS1 resulted in the absence of MhaB1/MhaB2 in the OM of mutants. These results are therefore consistent with the Mha proteins functioning as a TPS system. Furthermore, we discovered that these mhaC mutants exhibit markedly decreased binding to human epithelial cells relevant to pathogenesis by M. catarrhalis (Chang, HEp2, A549, and/or 16HBE14o(-)). Expression of O12E MhaC and MhaB1 in a nonadherent strain of Escherichia coli was found to increase the adherence of recombinant bacteria to HEp2 monolayers by sevenfold, thereby demonstrating that this M. catarrhalis TPS system directly mediates binding to human epithelial cells. The construction of isogenic mutants in the mhaB1 and mhaB2 genes of strain O35E also suggests that the MhaB proteins play distinct roles in M. catarrhalis adherence. 相似文献