全文获取类型
收费全文 | 107083篇 |
免费 | 6015篇 |
国内免费 | 647篇 |
专业分类
耳鼻咽喉 | 1043篇 |
儿科学 | 3487篇 |
妇产科学 | 2457篇 |
基础医学 | 15404篇 |
口腔科学 | 3922篇 |
临床医学 | 9714篇 |
内科学 | 24083篇 |
皮肤病学 | 2722篇 |
神经病学 | 10459篇 |
特种医学 | 2484篇 |
外国民族医学 | 1篇 |
外科学 | 9522篇 |
综合类 | 409篇 |
一般理论 | 48篇 |
预防医学 | 10707篇 |
眼科学 | 1720篇 |
药学 | 7466篇 |
中国医学 | 417篇 |
肿瘤学 | 7680篇 |
出版年
2024年 | 120篇 |
2023年 | 1027篇 |
2022年 | 2211篇 |
2021年 | 3649篇 |
2020年 | 2288篇 |
2019年 | 3075篇 |
2018年 | 3487篇 |
2017年 | 2665篇 |
2016年 | 3099篇 |
2015年 | 3423篇 |
2014年 | 4498篇 |
2013年 | 5872篇 |
2012年 | 8932篇 |
2011年 | 9289篇 |
2010年 | 5072篇 |
2009年 | 4260篇 |
2008年 | 7382篇 |
2007年 | 7375篇 |
2006年 | 6789篇 |
2005年 | 6324篇 |
2004年 | 5683篇 |
2003年 | 5054篇 |
2002年 | 4552篇 |
2001年 | 548篇 |
2000年 | 381篇 |
1999年 | 592篇 |
1998年 | 790篇 |
1997年 | 647篇 |
1996年 | 547篇 |
1995年 | 450篇 |
1994年 | 428篇 |
1993年 | 350篇 |
1992年 | 292篇 |
1991年 | 195篇 |
1990年 | 195篇 |
1989年 | 181篇 |
1988年 | 182篇 |
1987年 | 151篇 |
1986年 | 162篇 |
1985年 | 115篇 |
1984年 | 141篇 |
1983年 | 133篇 |
1982年 | 161篇 |
1981年 | 116篇 |
1980年 | 124篇 |
1979年 | 75篇 |
1978年 | 79篇 |
1977年 | 70篇 |
1976年 | 58篇 |
1974年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Combi R Sala E Villa N Crosti F Beccaria L Cogliardi A Tenchini ML Dalprà L 《Clinical dysmorphology》2008,17(1):35-39
Silver-Russell syndrome (SRS) is clinically variable although most cases have several common signs. Different chromosomes and chromosomal regions have been associated with SRS. Maternal uniparental disomy (UPD) of chromosome 7 is responsible for 5-10% of cases, probably because of an imbalance between maternal and paternal imprinted genes and more recently maternal duplication or epimutations in the 11p15 imprinted region have been described. To date, only two patients with maternal UPD7 and a mosaic condition for a supernumerary ring 7 marker have been reported, and we here report a further case. Standard QFQ banding of lymphocytes as well as fluorescence in-situ hybridization analyses were performed to identify and characterize the supernumerary marker. UPD testing was performed on both the patient's and parents' DNA using chromosome 7 microsatellite markers. The patient demonstrated a ring in about 4% of the analysed cells. On the basis of cytogenetic and molecular results, break points were tentatively identified as 7p11.2 and 7q21. Maternal hetero-/iso-UPD and a paternal origin for the supernumerary ring were demonstrated. Clinical data comparison between our patient who has a SRS phenotype and cases with hetero-/iso-UPD7 mat and mosaicism for a paternally derived chromosome 7 ring and previously reported ring 7 cases suggest that the SRS phenotype is probably because of the UPD rather than to the partial trisomy. 相似文献
992.
We report on three unrelated Brazilian patients with a holoprosencephaly phenotype, with variable central nervous system involvement, ano/microphthalmia, and first branchial arch anomalies. The features of these patients show a striking similarity to those of the patients reported by Guion-Almeida et al. (1999) and Ribeiro et al. (2005), thus confirming the existence of this rare condition. All cases are isolated and the etiology remains unknown. 相似文献
993.
de Macena Sobreira NL Alves MT Alvarez Perez AB Brunoni D Cernach MC 《Clinical dysmorphology》2008,17(2):145-148
We describe a stillborn female with acrofacial dysostosis and frontonasal dysplasia. She had protrusion of the forehead, with marked hypertelorism and absence of the nose but with the rhinencephalon present. Autopsy showed wide cranial sutures, severe hydrocephalus with separation of the right and left hemispheres of the brain, preservation of the olfactory bulb and first and second cranial nerves. The child also had small kidneys bilaterally, rectal atresia and an absent anus with rectovaginal fistula. These clinical findings suggest a new form of acrofacial dysostosis. 相似文献
994.
995.
996.
997.
Kaczmarek P Respondek-Liberska M Borowski D Wielgoś M Czuba B Oszukowski P 《Ginekologia polska》2007,78(11):861-864
OBJECTIVES: to confirm that fetal echocardiography is indeed possible in late first trimester and that it improves the standard of the so-called "genetic" ultrasound scan. MATERIAL AND METHODS: Early echocardiography was performed in 75 fetuses from high and low risk pregnancies. All fetuses underwent echocardiography examination in 18-22 weeks of gestation and established follow up. RESULTS: The most suitable method of visualization seems to be transabdominal examination, between 13.0-13.6 weeks of gestation, an transvaginal one, between 12.0-12.6 weeks of gestation, with 90% effectiveness. In researched group of 75 fetuses (with established follow up) there were four heart defects (5.3%). Three of them were diagnosed before 14th week of gestation. One case (tetralogy of Fallot) was overlooked. There were two false positive diagnosis verified at 20th week of gestation. CONCLUSIONS: Early echocardiography, especially between 12.0-13.6 weeks of gestation, is a possible and valuable method of diagnosis. Reference evaluation should be performed between 18 and 22 weeks of gestation. In cases with suspected anomalies karyotyping is recommended. Congenital heart disease diagnosed at late first trimester should be treated as the next potential marker of genetic disorder. 相似文献
998.
Lymphatic vessel density and epithelial D2-40 immunoreactivity in pre-invasive and invasive lesions of the uterine cervix 总被引:3,自引:0,他引:3
Longatto-Filho A Pinheiro C Pereira SM Etlinger D Moreira MA Jubé LF Queiroz GS Baltazar F Schmitt FC 《Gynecologic oncology》2007,107(1):45-51
OBJECTIVE: We sought to determine the significance of lymphatic vessel density (LVD) in pre-malignant lesions and carcinomas of the uterine cervix and to evaluate the prognostic value of lymphatic invasion and D2-40 positivity in tumor cells in the three histological types of invasive lesions. The correlation of LVD, lymphatic invasion and D2-40 positivity in tumor cells with EGFR and COX-2 expressions was also evaluated. METHODS: We studied 50 cervicitis, 50 low-grade squamous intraepithelial lesions (LSIL) (CIN1), 51 high-grade squamous intraepithelial lesions (HSIL) (CIN2/CIN3), 49 invasive squamous cells carcinomas (SCC), 43 adenocarcinomas (AC) and 30 adenosquamous cells carcinomas (ASC). The immunoreaction assay was performed using the monoclonal antibody D2-40. RESULTS: Significant differences in LVD were found among all categories of pre-invasive and invasive lesions (p=0.001 and p<0.001, respectively). LVD in invasive lesions was significantly greater than in pre-invasive lesions (p<0.001) and no significant association was found between LVD in invasive lesions and both lymph node invasion and/or metastasis. D2-40 positivity in tumor cells was associated with a better prognosis in ASC cases. EGFR and COX-2 expressions in invasive lesions were not associated with LVD; however, they correlated with both lymphatic invasion and D2-40 positivity in tumor cells. CONCLUSIONS: Lymphatic neovascularization begins early in intraepithelial lesions and continues to increase towards malignancy. Both lymphatic invasion and decrease in D2-40 expression in tumor cells appear to have a prognostic value. 相似文献
999.
Briana DD Boutsikou M Gourgiotis D Kontara L Baka S Iacovidou N Hassiakos D Malamitsi-Puchner A 《Journal of perinatal medicine》2007,35(4):326-329
OBJECTIVE: IGF-I and insulin are the main regulators of intrauterine and postnatal growth. Adipose tissue secreted cytokines are implicated in intrauterine growth. The relevant function of the adipocytokine visfatin is unknown. MATERIALS AND METHODS: Serum visfatin, IGF-I and insulin levels were measured by enzyme immunoassays in 40 singleton full-term fetuses and neonates on postnatal days 1(N1) and 4 (N4). RESULTS: No significant correlations exist between visfatin and IGF-I or insulin. N1 and N4 visfatin positively correlated with customized (adjusted) birth weight centiles (r=0.511, P=0.021, and r=0.597, P=0.005, respectively). Fetal and N1 IGF-I positively correlated with customized centiles (r=0.608, P<0.001 and r=0.485, P=0.006, respectively). Fetal insulin positively correlated with customized centiles (r=0.654, P=0.021). CONCLUSIONS: Potential implication of visfatin in fetal growth is probably not mediated by IGF-I or insulin. Although a more active role cannot be excluded, visfatin may simply represent a marker of fat accumulation. 相似文献
1000.