全文获取类型
收费全文 | 92909篇 |
免费 | 41635篇 |
国内免费 | 222篇 |
专业分类
耳鼻咽喉 | 1915篇 |
儿科学 | 4394篇 |
妇产科学 | 731篇 |
基础医学 | 18322篇 |
口腔科学 | 5222篇 |
临床医学 | 13743篇 |
内科学 | 25809篇 |
皮肤病学 | 7869篇 |
神经病学 | 14568篇 |
特种医学 | 3426篇 |
外科学 | 15569篇 |
综合类 | 70篇 |
一般理论 | 23篇 |
预防医学 | 4607篇 |
眼科学 | 1639篇 |
药学 | 7056篇 |
12篇 | |
中国医学 | 1164篇 |
肿瘤学 | 8627篇 |
出版年
2024年 | 49篇 |
2023年 | 187篇 |
2022年 | 520篇 |
2021年 | 2113篇 |
2020年 | 6111篇 |
2019年 | 11102篇 |
2018年 | 10508篇 |
2017年 | 11721篇 |
2016年 | 12595篇 |
2015年 | 12698篇 |
2014年 | 12768篇 |
2013年 | 13267篇 |
2012年 | 5676篇 |
2011年 | 5466篇 |
2010年 | 9731篇 |
2009年 | 5972篇 |
2008年 | 3027篇 |
2007年 | 1803篇 |
2006年 | 1652篇 |
2005年 | 1365篇 |
2004年 | 1165篇 |
2003年 | 1118篇 |
2002年 | 1140篇 |
2001年 | 975篇 |
2000年 | 895篇 |
1999年 | 428篇 |
1998年 | 95篇 |
1997年 | 82篇 |
1996年 | 61篇 |
1995年 | 48篇 |
1994年 | 46篇 |
1993年 | 47篇 |
1992年 | 47篇 |
1991年 | 47篇 |
1990年 | 33篇 |
1989年 | 30篇 |
1988年 | 21篇 |
1987年 | 30篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1971年 | 5篇 |
1968年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
M. Knösel W. Engelke H.‐J. Helms A. Bleckmann 《European journal of dental education》2012,16(3):131-137
Objective: To systematically assess the informational value, quality, intention, source and bias of web 2.0 footage whose aim is peer‐to‐peer education about oral implantology. Methods: YouTube ( http://www.youtube.com ) was scanned on 15 October 2010 for oral implantology‐related videos using an adequately pre‐defined search query. Search results were filtered with the system‐generated category ‘education’ and the additional criterion ‘most viewed’. Only those videos with at least 1000 views were included (total 124, of which 27 were excluded because they were not related to implantology). Filtered videos were discussed and rated with particular regard to the educational needs of potential groups of addressees [(i) undergraduates and laymen, (ii) dentists without or currently undergoing a specialisation in oral implantology and (iii) dentists who have completed a specialisation in the field of oral implantology] by a jury consisting of (i) an accredited post‐graduate university instructor with 22 years of professional teaching experience in the field of implantology, (ii) a university lecturer in dentistry/orthodontics with 10 years teaching experience and (iii) a university haematologist/oncologist. They were required to fill out a questionnaire for each video. The data were statistically analysed using non‐parametric ANOVA (α = 5%) and a sign test (α = 0.05/3 = 0.017). Results: The YouTube scan produced 1710 results in the category ‘EDU’. The analysis revealed that there is a wide range of instructional footage on this topic, but with highly variable range in quality and informational value. Footage intention was to large proportions (47.4%) a mixture of education and advertisement. Its usefulness differed significantly for the three groups of addressees, offering greater novelty to undergraduates and post‐graduates. Conclusion: YouTube and similar social media websites may have a potential capacity and value in complementing continuing education in the technique of oral implantology. As a means of achieving an acceptable level of knowledge about the topic when used alone, it should not be considered to be suitable at this point in time. 相似文献
992.
993.
Hillary L. Broder PhD MEd Maureen Wilson‐Genderson PhD Lacey Sischo PhD 《Journal of public health dentistry》2012,72(4):302-312
Objectives: This study assessed the reliability and validity of the Child Oral Health Impact Profile–Short Form 19 (COHIP‐SF 19) from the validated 34‐item COHIP. Methods: Participants included 205 pediatric, 107 orthodontic, and 863 patients with craniofacial anomalies (CFAs). Item level evaluations included examining content overlap, distributional properties, and use of the response set. Confirmatory factor analysis identified potential items for deletion. Scale reliability was assessed with Cronbach's alpha. Discriminant validity of the COHIP‐SF 19 was evaluated as follows: among pediatric participants, scores were compared with varying amounts of decayed and filled surfaces (DFS) and presence of caries on permanent teeth; for orthodontic patients, scores were correlated with anterior tooth spacing/crowding; and for those with CFA, scores were compared with clinicians' ratings of extent of defect (EOD) for nose and lip and/or speech hypernasality. Convergent validity was assessed by examining the partial Spearman correlation between the COHIP scores and a standard Global Health self‐rating. Comparisons between the COHIP and the COHIP‐SF 19 were completed across samples. Results: The reduced questionnaire consists of 19 items: Oral Health (five items), Functional Well‐Being (four items), and a combined subscale named Socio‐Emotional Well‐Being (10 items). Internal reliability is ≥0.82 for the three samples. Results demonstrate that the COHIP‐SF 19 discriminates within and across treatment groups by EOD and within a community‐based pediatric sample. The measure is associated with the Global Health rating (P < 0.05), thereby indicating convergent validity. Conclusions: Reliability and validity testing demonstrate that the COHIP‐SF 19 is a psychometrically sound instrument to measure oral health‐related quality of life across school‐aged pediatric populations. 相似文献
994.
C. Cunha Villar J. Chukwuedum Aniemeke X.‐R. Zhao G. Huynh‐Ba 《Molecular oral microbiology》2012,27(6):436-448
During infection, interactions between Candida albicans and oral epithelial cells result in oral epithelial cell death. This is clinically manifested by the development of oral mucosal ulcerations generally associated with discomfort. In vitro studies have shown that C. albicans induces early apoptotic alterations in oral epithelial cells; however, these studies have also shown that treatment of infected cells with caspase inhibitors does not prevent their death. The reasons for these contradictory results are unknown and it is still not clear if C. albicans stimulates oral epithelial signaling pathways that promote apoptotic cell death. Activation of specific death pathways in response to microbial organisms plays an essential role in modulating the pathogenesis of a variety of infectious diseases. The aim of this study was to (i) characterize C. albicans‐induced apoptotic morphological alterations in oral epithelial cells, and (ii) investigate the activation of apoptotic signaling pathways and expression of apoptotic genes during infection. Candida albicans induced early apoptotic changes in over 50% of oral epithelial cells. However, only 15% of those showed mid‐late apoptotic alterations. At the molecular level, C. albicans caused a loss of the mitochondrial transmembrane potential and translocation of mitochondrial cytochrome c. Caspase‐3/9 activities increased only during the first hours of infection. Moreover, poly[ADP ribose] polymerase 1 was cleaved into apoptotic and necrotic‐like fragments. Finally, five anti‐apoptotic genes were significantly upregulated and two pro‐apoptotic genes were downregulated during infection. Altogether, these findings indicate that epithelial apoptotic pathways are activated in response to C. albicans, but fail to progress and promote apoptotic cell death. 相似文献
995.
996.
ARMANDO E. SOTO‐ROJAS MAURICIO ESCOFFIÉ‐RAMÍREZ GLORIANA PÉREZ‐FERRERA JOSEPH A. GUIDO ANDRES A. MANTILLA‐RODRIGUEZ ESPERANZA A. MARTINEZ‐MIER 《International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children》2012,22(6):451-458
International Journal of Paediatric Dentistry 2012; 22: 451–458 Background. Dental sealants are an effective treatment for the prevention and management of caries. Objective. To determine the retention of sealants placed in a rural setting in Mexico as part of an international service‐learning (ISL) programme and to determine associations between dental sealant’s retention and caries diagnosis at the time of sealant placement. Methods. Children aged 6–15 were examined for dental caries, received sealants by dental students as part of an ISL programme, and were re‐examined 4, 2, or 1 years after placement to assess sealant survival. Sealants were placed on permanent sound surfaces and enamel caries lesions [International Caries Assessment and Detection System (ICDAS) criteria]. Sealant survival was explored using Cochran–Mantel–Haenszel tests and multivariate prediction models. Results. 219 (46%) of 478 (mean age = 10.53 SD = 5.11) children who had received sealants returned for a recall examination (mean age = 10.89 SD = 3.11). After 1–4 years, 96.4% to 60.6% of the sealants placed on sound teeth had survived, and for sealants placed on surfaces with enamel caries lesions (ICDAS 1–3), 94.2% to 55.6% had survived. Differences were not statistically significant. Conclusions. Sealants had survival rates comparable to those previously reported in the literature. Sealants placed on sound and enamel caries lesions had similar survival rates. 相似文献
997.
998.
V. Ahlgrimm‐Siess C. Massone A. Scope R. Fink‐Puches E. Richtig I.H. Wolf S. Koller A. Gerger J. Smolle R. Hofmann‐Wellenhof 《The British journal of dermatology》2009,161(6):1307-1316
Background Facial lentigo maligna (LM) and lentigo maligna melanoma (LMM) may be difficult to diagnose clinically and dermoscopically. Reflectance confocal microscopy (RCM) enables the in vivo assessment of equivocal skin lesions at a cellular level. Objectives To assess cytomorphological and architectural RCM features of facial LM/LMM. Methods Four women and eight men aged 58–88 years presenting with facial skin lesions suspicious of LM/LMM were included. In total, 17 lesion areas were imaged by RCM before biopsy. The histopathological diagnosis of LM was made in 15 areas; the other two were diagnosed as early LMM. Results A focal increase of atypical melanocytes and nests surrounding adnexal openings, sheets of mainly dendritic melanocytes, cord‐like rete ridges at the dermoepidermal junction (DEJ) and an infiltration of adnexal structures by atypical melanocytes were found to be characteristic RCM features of facial LM/LMM. Areas with a focal increase of atypical melanocytes and nests surrounding adnexal openings were observed at the basal layer in three cases. The remaining cases displayed these changes at suprabasal layers above sheets of mainly dendritic melanocytes. Cord‐like rete ridges at the DEJ and an infiltration of adnexal structures by atypical melanocytes were observed in all cases. Previously described criteria for RCM diagnosis of melanoma, such as epidermal disarray, pleomorphism of melanocytes and pagetoid spreading of atypical melanocytes, were additionally observed. Conclusions We observed a reproducible set of RCM criteria in this case series of facial LM/LMM. 相似文献
999.
Silke C. Hofmann Ocko Kautz Michael Hertl Michael Sticherling Detlef Zillikens Leena Bruckner‐Tuderman 《Journal der Deutschen Dermatologischen Gesellschaft》2009,7(3):227-233
Background: The lack of controlled trials on the treatment of pemphigus and pemphigoid diseases limits an evidence‐based therapy of these disorders.The aim of this survey was to assess the current treatment standards at German dermatological hospitals and the need for future therapeutic trials. Methods: A two‐page questionnaire was sent to 42 German academic and non‐academic dermatological hospitals and evaluated at the Department of Dermatology, University Medical Center, Freiburg. Results: The response rate was 76%. Topical clobetasol propionate treatment was regarded as first line therapy of bullous pemphigoid in 27% of the hospitals. More than 50% used systemic corticosteroids at an initial dose of ≤ 1 mg/kg prednisolone‐equivalent in pemphigus and pemphigoid. Azathioprine is used as first line adjuvant in pemphigoid and pemphigus treatment in 69% and 81% of the hospitals, respectively. Dapsone and mycophenolate mofetil represent alternative options, as well as cyclophosphamide‐dexamethasone‐pulse therapy in pemphigus. Immunosuppressive treatment of pemphigoid and pemphigus is terminated by 58% and 46% of the hospitals 1–3 months after clinical remission, respectively, but the given time points appeared to be variable. Conclusions: The high response rate to this survey demonstrates the interest in this topic. The variability of the answers regarding initial doses of corticosteroids and time points for termination of therapy indicates the need for the establishment of guidelines and for controlled therapeutic trials. 相似文献
1000.
Susanne Dugas‐Breit Pia Schpf Martin Dugas Helmut Schiffl Franziska Ruëff Bernhard Przybilla 《Journal der Deutschen Dermatologischen Gesellschaft》2005,3(5):343-347
Background: The pathogenesis of pruritus in renal disease is not yet understood. Evidence suggests that mast cells play a role; for example, the number of dermal mast cells is increased in patients on hemodialysis. Patients and methods: To investigate a possible role of mast cell tryptase in pruritus of patients undergoing chronic hemodialysis, serum mast cell tryptase concentrations were measured in blood samples taken from 93 such patients, 53 of whom also recorded the severity of their pruritus on a visual analogue scale. Results: Serum mast cell tryptase levels were above 11.4 µg/l (95th percentile) in 84 of 93 hemodialysis patients (90.3 %). The intensity of pruritus correlated significantly (p = 0.014) with the tryptase levels, an associated not yet shown for other mast cell‐related parameters. Conclusions: Mast cells or even tryptase itself may be involved in the pathogenesis of pruritus of hemodialysis patients. 相似文献