全文获取类型
收费全文 | 6978篇 |
免费 | 313篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 134篇 |
妇产科学 | 258篇 |
基础医学 | 531篇 |
口腔科学 | 133篇 |
临床医学 | 616篇 |
内科学 | 1944篇 |
皮肤病学 | 86篇 |
神经病学 | 373篇 |
特种医学 | 292篇 |
外科学 | 1399篇 |
综合类 | 26篇 |
预防医学 | 322篇 |
眼科学 | 146篇 |
药学 | 313篇 |
中国医学 | 5篇 |
肿瘤学 | 677篇 |
出版年
2024年 | 3篇 |
2023年 | 48篇 |
2022年 | 134篇 |
2021年 | 244篇 |
2020年 | 134篇 |
2019年 | 199篇 |
2018年 | 209篇 |
2017年 | 146篇 |
2016年 | 169篇 |
2015年 | 168篇 |
2014年 | 304篇 |
2013年 | 340篇 |
2012年 | 605篇 |
2011年 | 612篇 |
2010年 | 369篇 |
2009年 | 335篇 |
2008年 | 575篇 |
2007年 | 587篇 |
2006年 | 487篇 |
2005年 | 413篇 |
2004年 | 358篇 |
2003年 | 318篇 |
2002年 | 266篇 |
2001年 | 37篇 |
2000年 | 19篇 |
1999年 | 34篇 |
1998年 | 54篇 |
1997年 | 27篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 19篇 |
1993年 | 11篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1976年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有7368条查询结果,搜索用时 12 毫秒
41.
42.
Maternal risk of breast cancer following multiple births: a nationwide study in Sweden 总被引:2,自引:0,他引:2
Mats Lambe Chung-cheng Hsieh Shirng-wern Tsaih Anders Ekbom Hans-Olov Adami Dimitrios Trichopoulos 《Cancer causes & control : CCC》1996,7(5):533-538
The association between multiple births and subsequent maternal breast cancer risk was explored in a nested case-control study in Sweden encompassing 19,368 parous women with breast cancer diagnosed up to age 65 years, and 100,459 parous controls. Among cases and controls, there were 329 and 2,031 women, respectively, with a history of at least one live multiple birth. Compared with singleton mothers, breast cancer risk was 12 percent lower (odds ratio=0.088, 95 percent confidence interval=0.78–0.99) in women who had had a multiple birth. After stratification for age at diagnosis, evidence of a significant inverse association was found only in women aged 54 years or younger. Birth order of the multiple pregnancy had no apparent risk-modifying effect. Age at earliest multiple birth was unrelated to breast cancer risk. The inverse association between twinning and breast cancer risk may reflect protective physiological features of twin pregnancies. Further research is needed to investigate the role, if any, of in creased levels of steroid hormone-binding globulins in mothers of twins and the proposed inhibitory effects of human chorionic gonadotropin and -fetoprotein, both of which are increased during multiple gestations, on breast carcinogenesis. Breast feeding patterns in mothers of twins also may modify their risk of developing breast cancer.Ambors are with the Department of Cancer Epidemiology (Drs Lambe Ekbom, Adami) and Department of Social Medicine (Lambe), University Hospital, Uppsala, Sweden: Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA (Drs Hsieb, Tsilib, Adami, Ekbom, Trichopoulos); UMASS Cancer Center, Worcester, MA, USA (Dr Hsieb). Address correspondece to Dr Lambe, Department of Cancer Epidemiology, University Hospital, S-751 85 Uppsala, Sweden. This project is funded by grants from the Swedish Cencer Societv. the Swedish Societv of Medicine. and the Wahlmarks Fund at Uppsala City Council. 相似文献
43.
44.
Eleni Petridou Freda E. Alexander Dimitrios Trichopoulos Katharine Revinthi Nick Dessypris Naomi Wray Stavros Haidas Dimitrios Koliouskas Helen Kosmidis Fani Piperopoulou Fotini Tzortzatou 《Cancer causes & control : CCC》1997,8(2):239-245
A total of 872 children aged up to 14 years, who were diagnosed withleukemia in Greece during the decade 1980-89, were allocated by place ofresidence to the 601 administrative districts of the country. Evaluation ofspatial clustering was done using the Potthoff-Whittinghill method, whichvalidly assesses heterogeneity of leukemia risk among districts with variableexpected numbers of cases. There was highly significant evidence for spatialclustering occurring particularly among children living in urban and, to alesser extent, semi-urban areas. The evidence was stronger for childrenyounger than 10 years old, applied also to children in different five-yearage groups, and persisted when cases of acute lymphoblastic leukemia wereanalyzed separately. These findings provide support to the hypothesis thatlocalized environmental exposures could contribute to the etiology ofchildhood leukemia, but they cannot distinguish between exposures of physicalor chemical nature, nor can they exclude socially conditioned patterns ofexposure to infectious agents. 相似文献
45.
The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies 总被引:3,自引:0,他引:3
Geoffrey R. Howe Kristan J. Aronson Enrique Benito Roberto Castelleto Jacqueline Cornée Stephen Duffy Richard P. Gallagher José M. Iscovich Jiao Deng-ao Rudolf Kaaks Gabriel A. Kune Susan Kune Hin P. Lee Marion Lee Anthony B. Miller Ruth K. Peters John D. Potter Elio Riboli Martha L. Slattery Dimitrios Trichopoulos Albert Tuyns Anastasia Tzonou Lyndsey F. Watson Alice S. Whittemore Anna H. Wu-Williams Zheng Shu 《Cancer causes & control : CCC》1997,8(2):215-228
The objective of this study was to examine the effects of the intakeof dietary fat upon colorectal cancer risk in a combined analysis of datafrom 13 case-control studies previously conducted in populations withdiffering colorectal cancer rates and dietary practices. Original datarecords for 5,287 cases of colorectal cancer and 10,470 controls werecombined. Logistic regression analysis was used to estimate odds ratios (OR)for intakes of total energy, total fat and its components, and cholesterol.Positive associations with energy intake were observed for 11 of the 13studies. However, there was little, if any, evidence of anyenergy-independent effect of either total fat with ORs of 1.00, 0.95, 1.01,1.02, and 0.92 for quintiles of residuals of total fat intake (P trend =0.67) or for saturated fat with ORs of 1.00, 1.08, 1.06, 1.21, and 1.06 (Ptrend = 0.39). The analysis suggests that, among these case-control studies,there is no energy-independent association between dietary fat intake andrisk of colorectal cancer. It also suggests that simple substitution of fatby other sources of calories is unlikely to reduce meaningfully the risk ofcolorectal cancer. 相似文献
46.
Charles Butts Nevin Murray Andrew Maksymiuk Glenwood Goss Ernie Marshall Denis Soulières Yvon Cormier Peter Ellis Allan Price Ravinder Sawhney Mary Davis Janine Mansi Colum Smith Dimitrios Vergidis Paul Ellis Mary MacNeil Martin Palmer 《Journal of clinical oncology》2005,23(27):6674-6681
PURPOSE: To evaluate the effect of BLP25 liposome vaccine (L-BLP25) on survival and toxicity in patients with stage IIIB and IV non-small-cell lung cancer (NSCLC). Secondary objectives included health-related quality of life (QOL) and immune responses elicited by L-BLP25. PATIENTS AND METHODS: Patients with an Eastern Cooperative Oncology Group performance status of 0 to 2 and stable or responding stage IIIB or IV NSCLC after any first-line chemotherapy were prestratified by stage and randomly assigned to either L-BLP25 plus best supportive care (BSC) or BSC alone. Patients in the L-BLP25 arm received a single intravenous dose of cyclophosphamide 300 mg/m2 followed by eight weekly subcutaneous immunizations with L-BLP25 (1,000 microg). Subsequent immunizations were administered at 6-week intervals. RESULTS: The survival results indicate a median survival time of 4.4 months longer for patients randomly assigned to the L-BLP25 arm (88 patients) compared with patients assigned to the BSC arm (83 patients; adjusted hazard ratio [HR] = 0.739; 95% CI, 0.509 to 1.073; P = .112). The greatest effect was observed in stage IIIB locoregional (LR) patients, for whom the median survival time for the L-BLP25 arm has not yet been reached compared with 13.3 months for the BSC arm (adjusted HR = 0.524; 95% CI, 0.261 to 1.052; P = .069). No significant toxicity was observed. QOL was maintained longer in patients on the L-BLP25 arm. CONCLUSION: L-BLP25 maintenance therapy in patients with advanced NSCLC is feasible with minimal toxicity. The survival difference of 4.4 months observed with the vaccine did not reach statistical significance. In the subgroup of patients with stage IIIB LR disease, a strong trend in 2-year survival in favor of L-BLP25 was observed. 相似文献
47.
François-Clément Bidard Dieter J Peeters Tanja Fehm Franco Nolé Rafael Gisbert-Criado Dimitrios Mavroudis Salvatore Grisanti Daniele Generali Jose A Garcia-Saenz Justin Stebbing Carlos Caldas Paola Gazzaniga Luis Manso Rita Zamarchi Angela Fernandez de Lascoiti Leticia De Mattos-Arruda Michail Ignatiadis Ronald Lebofsky Stefan Michiels 《The lancet oncology》2014,15(4):406-414
48.
Negri E Ron E Franceschi S Dal Maso L Mark SD Preston-Martin S McTiernan A Kolonel L Kleinerman R Land C Jin F Wingren G Galanti MR Hallquist A Glattre E Lund E Levi F Linos D Braga C La Vecchia C 《Cancer causes & control : CCC》1999,10(2):131-142
Objective: Because the etiology of thyroid cancer is not well described, we conducted a pooled analysis of all published case- control studies, as well as two identified unpublished studies. This paper describes the major characteristics of the 14 studies included in the analysis, as well as the statistical methods employed. Four studies were conducted in the United States (1 each in Washington State, California, Connecticut and Hawaii), 8 in Europe (3 in Sweden, 2 in Norway, 1 in Switzerland, 1 in Italy and 1 in Greece), and 2 in Asia (1 in China and 1 in Japan).Methods: The original datasets were obtained and restructured in a uniform format. Data on socio-demographic characteristics, anthropometric measures, smoking and alcohol consumption, history of benign thyroid diseases and of other selected medical conditions and treatments, family history of cancer and of benign thyroid conditions, occupation, residence in endemic goitre areas, and dietary habits were analyzed. For women, we also analyzed menstrual and reproductive factors and use of female hormones. Radiotherapy and, in Japan, exposure to the A-bombs were considered as potential confounding factors.Results: A total of 2,725 cases (2,247 females and 478 males) and 4,776 controls (3,699 females and 1,077 males) were included in this study. Of the cases, 79% were classified as papillary thyroid carcinomas, 14% as follicular, 2% medullary, 1% anaplastic, 1% other histologies, and 3% histological type unknown. Each of the datasets was checked for outliers and consistency. Data were analysed separately by study center, gender, and the two major histologic types (papillary, follicular). Frequency tables and simple statistics were computed for each variable under study. Conditional logistic regression was used to compute odds ratios. For matched studies, the original matching was preserved, whereas, for unmatched ones, five-year age groups were used for matching. Study-specific analyses were computed, and then the data from all the studies were pooled conditioning on study. Heterogeneity between studies, geographic areas and study designs was assessed, and the modifying effect of age was also evaluated. 相似文献
49.
Maria Mantzorou Dimitrios Papandreou Georgios K. Vasios Eleni Pavlidou Georgios Antasouras Evmorfia Psara Zainab Taha Efthymios Poulios Constantinos Giaginis 《Nutrients》2022,14(17)
Introduction: Obesity is a current public health concern. Higher body weight is influenced by genetic and environmental parameters, and their interplay and is associated with a greater risk for several chronic diseases. Breastfeeding has been suggested as a preventive measure against obesity, which can further reduce long-term negative health outcomes for both women and children. Aim: The aim of the present study was to evaluate the role of breastfeeding on maternal and childhood overweight and obesity. Materials and Methods: This is a cross-sectional study conducted on 2515 healthy mothers and their children, aged 2–5 years, enrolled from nine different Greek rural and urban regions. Validated, standardized questionnaires were administrated that included anthropometric indices, socio-demographic characteristics of mothers and children, as well as breastfeeding practices. Results: Overall, 68% of participated women exclusively breastfed their children for at least 4 months. Mothers that exclusively breastfed showed a significantly lower prevalence of overweight and obesity after 2–5 years from delivery (p < 0.0001). Children that had exclusively been breastfed showed a significantly lower prevalence of overweight and obesity at the age of 2–5 years (p < 0.0001). Using multivariate regression analysis, exclusive breastfeeding for at least 4 months was associated with a two-fold lower risk for maternal and childhood overweight and obesity after 2–5 years from delivery, independent from maternal age, educational and economic status, and smoking habits (p < 0.0001). Conclusion: Exclusive breastfeeding for at least 4 months had a positive effect on childhood overweight and obesity, also contributing beneficially to post-natal maternal weight control. The beneficial effects of breastfeeding should be communicated to future and new mothers, while supportive actions for all mothers to initiate and continue breastfeeding their offspring should be implemented. 相似文献
50.
Kiriakos Stefanidis Dorothea Tsatsou Dimitrios Konstantinidis Lazaros Gymnopoulos Petros Daras Saskia Wilson-Barnes Kathryn Hart Vronique Cornelissen Elise Decorte Elena Lalama Andreas Pfeiffer Maria Hassapidou Ioannis Pagkalos Anagnostis Argiriou Konstantinos Rouskas Stelios Hadjidimitriou Vasileios Charisis Sofia Balula Dias Jos Alves Diniz Gonalo Telo Hugo Silva Alex Bensenousi Kosmas Dimitropoulos 《Nutrients》2022,14(20)
AI-based software applications for personalized nutrition have recently gained increasing attention to help users follow a healthy lifestyle. In this paper, we present a knowledge-based recommendation framework that exploits an explicit dataset of expert-validated meals to offer highly accurate diet plans spanning across ten user groups of both healthy subjects and participants with health conditions. The proposed advisor is built on a novel architecture that includes (a) a qualitative layer for verifying ingredient appropriateness, and (b) a quantitative layer for synthesizing meal plans. The first layer is implemented as an expert system for fuzzy inference relying on an ontology of rules acquired by experts in Nutrition, while the second layer as an optimization method for generating daily meal plans based on target nutrient values and ranges. The system’s effectiveness is evaluated through extensive experiments for establishing meal and meal plan appropriateness, meal variety, as well as system capacity for recommending meal plans. Evaluations involved synthetic data, including the generation of 3000 virtual user profiles and their weekly meal plans. Results reveal a high precision and recall for recommending appropriate ingredients in most user categories, while the meal plan generator achieved a total recommendation accuracy of 92% for all nutrient recommendations. 相似文献