全文获取类型
收费全文 | 4473篇 |
免费 | 223篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 101篇 |
妇产科学 | 109篇 |
基础医学 | 411篇 |
口腔科学 | 104篇 |
临床医学 | 349篇 |
内科学 | 1091篇 |
皮肤病学 | 54篇 |
神经病学 | 156篇 |
特种医学 | 293篇 |
外国民族医学 | 1篇 |
外科学 | 782篇 |
综合类 | 124篇 |
一般理论 | 3篇 |
预防医学 | 256篇 |
眼科学 | 130篇 |
药学 | 369篇 |
中国医学 | 13篇 |
肿瘤学 | 351篇 |
出版年
2023年 | 47篇 |
2022年 | 137篇 |
2021年 | 234篇 |
2020年 | 98篇 |
2019年 | 134篇 |
2018年 | 173篇 |
2017年 | 91篇 |
2016年 | 90篇 |
2015年 | 121篇 |
2014年 | 164篇 |
2013年 | 196篇 |
2012年 | 300篇 |
2011年 | 291篇 |
2010年 | 191篇 |
2009年 | 154篇 |
2008年 | 247篇 |
2007年 | 265篇 |
2006年 | 237篇 |
2005年 | 234篇 |
2004年 | 163篇 |
2003年 | 161篇 |
2002年 | 155篇 |
2001年 | 63篇 |
2000年 | 76篇 |
1999年 | 49篇 |
1998年 | 42篇 |
1997年 | 41篇 |
1996年 | 20篇 |
1995年 | 28篇 |
1994年 | 25篇 |
1993年 | 27篇 |
1992年 | 43篇 |
1991年 | 42篇 |
1990年 | 36篇 |
1989年 | 32篇 |
1988年 | 41篇 |
1987年 | 26篇 |
1986年 | 37篇 |
1985年 | 18篇 |
1984年 | 21篇 |
1983年 | 14篇 |
1980年 | 14篇 |
1979年 | 9篇 |
1978年 | 13篇 |
1977年 | 22篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1974年 | 8篇 |
1970年 | 10篇 |
1969年 | 12篇 |
排序方式: 共有4721条查询结果,搜索用时 15 毫秒
91.
Herman P Pugliese V D'Albuquerque LA Saad WA Pinotti HW 《Arquivos de gastroenterologia》1998,35(3):186-189
Biliary cystadenoma is a rare benign disease, with unknown etiology and is considered as a pre-malignant lesion. Until 1988, only 71 cases had been reported. The authors present three cases and discuss the diagnosis and treatment and the disease. 相似文献
92.
Raffaele Ferrari Saad Dawoodi Merrill Raju Avinash Thumma Linda S. Hynan Shirin Hejazi Maasumi Joan S. Reisch Sid O'Bryant Marjorie Jenkins Robert Barber Parastoo Momeni 《Neurobiology of aging》2013
Women are at a 2-fold risk of developing late-onset Alzheimer's disease (AD) (onset at 65 years of age or older) compared with men. During perimenopausal years, women undergo hormonal changes that are accompanied by metabolic, cardiovascular, and inflammatory changes. These all together have been suggested as risk factors for late-onset AD. However, not all perimenopausal women develop AD; we hypothesize that certain genetic factors might underlie the increased susceptibility for developing AD in postmenopausal women. We investigated the Androgen Receptor gene (AR) in a clinical cohort of male and female AD patients and normal control subjects by sequencing all coding exons and evaluating the length and distribution of the CAG repeat in exon 1. We could not establish a correlation between the repeat length, sex, and the disease status, nor did we identify possible pathogenic variants. AR is located on the X chromosome; to assess its role in AD, X-inactivation patterns will need to be studied to directly correlate the actual expressed repeat length to a possible sex-specific phenotypic effect. 相似文献
93.
Anna Kolecka Kantarawee Khayhan Marizeth Groenewald Bart Theelen Michael Arabatzis Aristea Velegraki Markus Kostrzewa Mihai Mares Saad J. Taj-Aldeen Teun Boekhout 《Journal of clinical microbiology》2013,51(8):2491-2500
Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was used for an extensive identification study of arthroconidial yeasts, using 85 reference strains from the CBS-KNAW yeast collection and 134 clinical isolates collected from medical centers in Qatar, Greece, and Romania. The test set included 72 strains of ascomycetous yeasts (Galactomyces, Geotrichum, Saprochaete, and Magnusiomyces spp.) and 147 strains of basidiomycetous yeasts (Trichosporon and Guehomyces spp.). With minimal preparation time, MALDI-TOF MS proved to be an excellent diagnostic tool that provided reliable identification of most (98%) of the tested strains to the species level, with good discriminatory power. The majority of strains were correctly identified at the species level with good scores (>2.0) and seven of the tested strains with log score values between 1.7 and 2.0. The MALDI-TOF MS results obtained were consistent with validated internal transcribed spacer (ITS) and/or large subunit (LSU) ribosomal DNA sequencing results. Expanding the mass spectrum database by increasing the number of reference strains for closely related species, including those of nonclinical origin, should enhance the usefulness of MALDI-TOF MS-based diagnostic analysis of these arthroconidial fungi in medical and other laboratories. 相似文献
94.
Samar Samir Youssef Asmaa Mostafa Abd El-Aal Amr Saad Moataza Hassan Omran Taher El Zanaty Sameh Mohamed Seif 《Disease markers》2013,35(5):431-437
Introduction. Hepatitis C virus (HCV) infection affects almost 3% of the world''s population with the highest prevalence in Egypt (15%). The standard therapy; pegylated interferon (PEG-IFN) and ribavirin, is effective in only 60% of Egyptian patients; moreover it is costly, prolonged, and has severe side effects, so prediction of response is essential to reduce burden of unfavorable treatment. Several viral and host factors have been proved to affect response to the treatment PEG-IFN and ribavirin; the strongest of them is polymorphisms near IL28B; nonetheless, nonresponse in patients with favorable IL28B is still unexplained, which implies the importance of studying other immunological factors that may correlate with response. Interleukin 12 (IL-12) is one of the most important proinflammatory cytokine presented with the initiation of immune response, determining Th1 and Th2 differentiation. A functional single nucleotide polymorphism (A/C) at the 3′ untranslated region (3′UTR) at position 1188 (NCBI SNP database no 3212227) was reported to be associated with responding more efficiently to antiviral combination therapy in HCV genotype 1 infected patients. The present study aims to evaluate association between this polymorphism with fibrosis stages, necroinflammation activity, response to the combined therapy, and gender in Egyptian HCV genotype 4. Material and Methods. A total of 133 Egyptian chronic HCV (CHCV) patients were treated with IFN/RBV and were followed up. IL12B 1188 A/C genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PRC-RFLP) analysis. Results. A nonsignificant trend for higher sustained virological response (SVR) was observed in patients homozygote for IL12B 1188 A/C SNP CC genotype (69% SVR versus 30.8% NR) only but not in AC and AA genotypes. No association was detected between IL12B 1188 A/C polymorphism and less severe fibrosis or less liver activity. By stratification of response according to gender genotype, a significant difference in response between males and females was seen among AA genotype carriers only due to high number of non responder females. Conclusion. IL12B CC genotype appears to have some influence on SVR achievement but not on severe fibrosis and severe necroinflamation activity. Females carrying A/A genotype of IL12B 1188 A/C SNP achieve less SVR than those carrying AC and CC genotypes. 相似文献
95.
M. L. Barjas-Castro M. C. P. Soares R. C. Menezes M. H. M. Carvalho F. F. Costa S. T. O. Saad 《Annals of human biology》2013,40(2):220-224
Background : The Parakanã is a group of Indians with cultural similarities to the extinct Tupi group. They are an isolated native population from East Brazilian Amazon. A number of different O alleles have been found at the blood group ABO locus in populations of several ethnic origins (Caucasians, Blacks, Amerindians). Aim : The present study describes the ABO blood group polymorphism gene of the Parakanã Indians. The Amerindian group was carefully selected for racial background. Subject and methods : The blood group polymorphism was analysed in genomic DNA from 62 Parakanã Indians. We determined the 261G deletion, the T646A and C771T mutations described in O 1variant and the G542A substitution, using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). Results : All Amerindians studied were homozygous for the 261G deletion. The frequencies of the T646A and C771T mutations in Parakanãs (0.65) were lower than that observed in Kayapo, Yanomama and Arara Indians (0.91) ( h 2 = 18.24; p-v < 0.001. The G542A substitution in Parakanãs was also lower (0.22) than in other tribes (0.42) ( h 2 = 9.73; p-v = 0.001). Conclusions : The different O alleles including the G542A mutation are not distributed homogeneously among all Amazonian Amerindians. Our results are in agreement with other genetic markers studied previously in Parakanã Indians, whose distinct genetic pattern differs from Europeans and even from other Amerindians. 相似文献
96.
Mohamed Labib Salem Abdel-Aziz A. Zidan Randa Ezz El-Din El-Naggar Mohamed Attia Saad Mohamed El-Shanshory Usama Bakry Mona Zidan 《Human immunology》2021,82(1):36-45
BackgroundRelapse remains a critical challenge in children with acute lymphoblastic leukemia (ALL). The emergence of immunoregulatory cells, including myeloid-derived suppressor cells (MDSCs), and T regulatory (Treg) cells, has been considered one potential mechanism of relapse in children with ALL.AimThis study aimed to address the microRNAs (miRNAs) related to MDSCs and Treg cells and to explore their targeted immunoregulatory pathways.MethodsAffymetrix microarray was used for global miRNA profiling in B-ALL pediatric patients before, during, and after induction of chemotherapy. Bioinformatics analysis was performed on MDSCs and Treg cells-related dysregulated miRNAs, and miR-Pathway analysis was performed to explore their targeted immunoregulatory pathways.Results516 miRNAs were dysregulated in ALL patients as compared to the healthy donor. Among them, 13 miRNAs and 8 miRNAs related to MDSCs and Treg cells, respectively, were common in all patients. Besides, 12 miRNAs were shared between MDSCs and Treg cells; 4 of them were common in all patients. Four immune-related pathways; TNF, TGF-β, FoxO, and Hippo were found implicated.ConclusionOur pilot study concluded certain miRNAs related to MDSCs and Treg cells, these miRNAs were linked to immunoregulatory pathways. Our results open avenues for testing those miRNA as molecular biomarkers for the immunosuppressive tumor microenvironment. 相似文献
97.
98.
99.
Teik Hin Tan Zanariah Hussein Fathinul Fikri Ahmad Saad Ibrahim Lutfi Shuaib 《Nuclear Medicine and Molecular Imaging》2015,49(2):143-151
Purpose
To evaluate the diagnostic performance of 68Ga-DOTATATE 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT), 18F-FDG PET/CT and 131I-MIBG scintigraphy in the mapping of metastatic pheochromocytoma and paraganglioma.Materials and Methods
Seventeen patients (male = 8, female = 9; age range, 13–68 years) with clinically proven or suspicious metastatic pheochromocytoma or paraganglioma were included in this prospective study. Twelve patients underwent all three modalities, whereas five patients underwent 68Ga-DOTATATE and 131I-MIBG without 18F-FDG. A composite reference standard derived from anatomical and functional imaging findings, along with histopathological information, was used to validate the findings. Results were analysed on a per-patient and on per-lesion basis. Sensitivity and accuracy were assessed using McNemar’s test.Results
On a per-patient basis, 14/17 patients were detected in 68Ga-DOTATATE, 7/17 patients in 131I-MIBG, and 10/12 patients in 18F-FDG. The sensitivity and accuracy of 68Ga-DOTATATE, 131I-MIBG and 18F-FDG were (93.3 %, 94.1 %), (46.7 %, 52.9 %) and (90.9 %, 91.7 %) respectively. On a per-lesion basis, an overall of 472 positive lesions were detected; of which 432/472 were identified by 68Ga-DOTATATE, 74/472 by 131I-MIBG, and 154/300 (patient, n = 12) by 18F-FDG. The sensitivity and accuracy of 68Ga-DOTATATE, 131I-MIBG and 18F-FDG were (91.5 %, 92.6 % p < 0.0001), (15.7 %, 26.0 % p < 0.0001) and (51.3 %, 57.8 % p < 0.0001) respectively. Discordant lesions were demonstrated on 68Ga-DOTATATE, 131I-MIBG and 18F-FDG.Conclusions
Ga-DOTATATE PET/CT shows high diagnostic accuracy than 131I-MIBG scintigraphy and 18F-FDG PET/ CT in mapping metastatic pheochromocytoma and paraganglioma. 相似文献100.
Joseph W. Owen Kathryn J. Fowler Maria B. Doyle Nael E. Saad David C. Linehan William C. Chapman 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2016,18(3):296-303