全文获取类型
收费全文 | 1944篇 |
免费 | 181篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 74篇 |
妇产科学 | 76篇 |
基础医学 | 241篇 |
口腔科学 | 106篇 |
临床医学 | 174篇 |
内科学 | 425篇 |
皮肤病学 | 14篇 |
神经病学 | 107篇 |
特种医学 | 43篇 |
外科学 | 311篇 |
综合类 | 34篇 |
一般理论 | 3篇 |
预防医学 | 202篇 |
眼科学 | 68篇 |
药学 | 129篇 |
中国医学 | 25篇 |
肿瘤学 | 80篇 |
出版年
2023年 | 17篇 |
2022年 | 22篇 |
2021年 | 27篇 |
2020年 | 39篇 |
2019年 | 34篇 |
2018年 | 41篇 |
2017年 | 30篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 48篇 |
2013年 | 67篇 |
2012年 | 114篇 |
2011年 | 120篇 |
2010年 | 58篇 |
2009年 | 45篇 |
2008年 | 103篇 |
2007年 | 119篇 |
2006年 | 106篇 |
2005年 | 102篇 |
2004年 | 105篇 |
2003年 | 79篇 |
2002年 | 93篇 |
2001年 | 62篇 |
2000年 | 56篇 |
1999年 | 57篇 |
1998年 | 28篇 |
1997年 | 21篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 24篇 |
1991年 | 26篇 |
1990年 | 32篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 25篇 |
1986年 | 26篇 |
1985年 | 17篇 |
1984年 | 22篇 |
1983年 | 21篇 |
1982年 | 14篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1976年 | 11篇 |
1974年 | 9篇 |
1973年 | 14篇 |
1972年 | 16篇 |
1967年 | 8篇 |
排序方式: 共有2131条查询结果,搜索用时 78 毫秒
81.
Holly D. Mitchell Tatiana Garcia Vilaplana Sema Mandal Natasha Ratna Megan Glancy Ammi Shah Ruth Simmons Celia Penman Freja Kirsebom Annastella Costella Alison E. Brown Hamish Mohammed Valerie Delpech Katy Sinka Gwenda Hughes 《Emerging infectious diseases》2022,28(3):739
Since the coronavirus disease pandemic response began in March 2020, tests, vaccinations, diagnoses, and treatment initiations for sexual health, HIV, and viral hepatitis in England have declined. The shift towards online and outreach services happened rapidly during 2020 and highlights the need to evaluate the effects of these strategies on health inequalities. 相似文献
82.
83.
Whitson EL Bugni TS Chockalingam PS Concepcion GP Harper MK He M Hooper JN Mangalindan GC Ritacco F Ireland CM 《Journal of natural products》2008,71(7):1213-1217
Three new sterol sulfates, spheciosterol sulfates A-C (1-3), and the known sterol sulfate topsentiasterol sulfate E (4) have been isolated from the sponge Spheciospongia sp., collected in the Philippines. Structures were assigned on the basis of extensive 1D and 2D NMR studies as well as analysis by HRESIMS. Compounds 1-4 inhibited PKCzeta with IC50 values of 1.59, 0.53, 0.11, and 1.21 microM, respectively. In a cell-based assay, 1-4 also inhibited NF-kappaB activation with EC50 values of 12-64 microM. 相似文献
84.
85.
Philip J. Schluter Deborah A. Askew Victoria A. McKelvey Hamish A. Jamieson Martin Lee 《Journal of the American Medical Directors Association》2021,22(6):1177-1183.e1
ObjectivesTo describe the oral health status and dental service use of older adults with complex needs living within the community and aged residential care (ARC) facility settings, and to determine associations between dental service utilization and sociodemographic variables.DesignSecondary analysis of 2 continuously recruited national cohorts.Setting and ParticipantsAdults aged ≥65 years having standardized assessments between July 1, 2012, and May 31, 2018, within New Zealand and who provided consent.MethodsAll community-living older people with complex needs undergo a standardized assessment, using the Home Care International Residential Assessment Instrument (interRAI-HC), whereas all ARC facility residents undergo Long Term Care Facilities assessments (interRAI-LTCF). Anonymized data from consenting participants were extracted. Cross-sectional analyses of oral health status and dental service use variables employed logistic regression models, whereas longitudinal analysis of factors influencing dental service utilization employed binary generalized estimating equation models.ResultsOverall, 144,380 interRAI-HC assessments from 97,229 participants, and 195,549 interRAI-LTCF assessments from 62,798 participants were eligible. At first assessment, their average age was 81.9 years (range: 65-109 years) and 84.4 years (range: 65-110 years), respectively. Approximately 65% of the participants wore dentures; 9% had broken, fragmented, loose, or otherwise nonintact natural teeth; and 10% reported difficulties chewing. Overall, only 25.3% of community-dwelling older adults and 17.5% of ARC residents had a dental examination within the previous year. Stark inequalities were observed with, for example, Māori participants having adjusted odds 3.14 [95% confidence interval (CI): 2.88, 3.42] and 2.08 (95% CI: 1.81, 2.39) of not having a dental examination in community and ARC facility settings compared with their New Zealand European counterparts.Conclusions and ImplicationsHeavy and unequal oral health burdens were observed among older adults with complex needs, together with low dental service uptake. New Zealand needs an oral health policy for older adults. 相似文献
86.
87.
88.
T F Smith T A Ireland G S Zaatari B B Gay G T Zwiren H G Andrews 《American journal of diseases of children (1960)》1985,139(10):1039-1044
This study evaluated by chart review the clinical, allergic, pathologic, and immunologic characteristics of 20 children found to have chronic bronchitis (CB) by bronchoscopic evaluation, including 13 children in whom CB was documented by endobronchial biopsy. Two additional children likely to have had CB also are described. In this study group, all of the patients were believed to have asthma as well. Chronic bronchitis was predicted by chronicity of symptoms and incomplete response to bronchodilators and corticosteroids, but it was not predicted by a history of allergy or laboratory evidence of systemic infection or inflammation. In the children described herein, CB often was associated with an IgG subclass abnormality. Bronchoscopic evaluation documented CB and provided biopsy and secretion samples. Although the histomorphic findings were heterogeneous, patients with CB usually had white blood cells present on Gram stains of secretions in addition to mononuclear cell infiltrates on biopsy specimens. Chronic bronchitis in these children seems to be distinct from CB in adults. Further studies will be needed to define CB in children. 相似文献
89.
Differentiation of chick lens epithelial cells: involvement of the epidermal growth factor receptor and endogenous ligand 总被引:1,自引:0,他引:1
PURPOSE: To characterize the constitutively activated epidermal growth factor receptor in a lens epithelial cell population experiencing initial stages of lens fiber formation, the chick lens annular pad. METHODS: Phosphotyrosine levels of the receptor were examined with western blot analysis and immunoprecipitation after ligand stimulation. Endogenous receptor ligands were immunologically identified in whole cell lysates of freshly isolated cells. The expression of lens fiber-specific differentiation marker proteins was examined with western blot analysis and enzyme-linked immunosorbent assay (ELISA) in short-term primary cultures of annular pad cells exposed to ligand. RESULTS: The major phosphotyrosine-containing protein in annular pad cells comigrated with the epidermal growth factor receptor and increased its phosphotyrosine content after epidermal growth factor treatment. Both time- and dose-dependent responses were noted. The constitutive activation of the receptor was determined in the presence of phosphatase inhibitors. Endogenous transforming growth factor-alpha, but not epidermal growth factor, was detected in freshly isolated cells. Transforming growth factor-alpha (TGF-alpha) treatment produced greater increases in receptor phosphotyrosine levels than equimolar levels of epidermal growth factor. Finally, TGF-alpha treatment induced increased expression of the beaded filament protein filensin when compared with control cells. Filensin expression was increased further when cells were costimulated with TGF-alpha and cAMP analogs. CONCLUSIONS: At least in the postnatal lens, endogenous TGF-alpha may affect overall growth patterns by modulating differentiation-specific protein expression. Furthermore, signaling pathways elicited by TGF-alpha and cAMP analogs converge to cooperatively enhance lens fiber differentiation. 相似文献
90.
PURPOSE: To develop and evaluate a new method to quantify centration of the trephined donor cornea relative to the limbus. METHODS: After human donor corneas were trephined for penetrating keratoplasty, the remaining corneoscleral discs were stained and subjected to image analysis. The centration of the excised donor cornea relative to the limbus was calculated by measuring their centroids from the "captured" images. RESULTS: Fifty-two corneoscleral discs were analyzed. The average deviation from the centre was 0.32 mm (SD, 0.18 mm). Neither surgeon nor the type of trephine significantly influenced the mean centroid deviation. CONCLUSION: We have developed and evaluated a method to quantify centration of human donor cornea. In a small series, decentration did not correlate significantly with either the surgeon or the trephine. 相似文献