全文获取类型
收费全文 | 1582篇 |
免费 | 185篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 144篇 |
妇产科学 | 24篇 |
基础医学 | 201篇 |
口腔科学 | 90篇 |
临床医学 | 162篇 |
内科学 | 346篇 |
皮肤病学 | 49篇 |
神经病学 | 32篇 |
特种医学 | 173篇 |
外科学 | 240篇 |
综合类 | 38篇 |
预防医学 | 99篇 |
眼科学 | 40篇 |
药学 | 53篇 |
中国医学 | 2篇 |
肿瘤学 | 96篇 |
出版年
2023年 | 14篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 15篇 |
2019年 | 8篇 |
2018年 | 46篇 |
2017年 | 46篇 |
2016年 | 41篇 |
2015年 | 60篇 |
2014年 | 76篇 |
2013年 | 109篇 |
2012年 | 53篇 |
2011年 | 31篇 |
2010年 | 77篇 |
2009年 | 93篇 |
2008年 | 33篇 |
2007年 | 54篇 |
2006年 | 55篇 |
2005年 | 30篇 |
2004年 | 33篇 |
2003年 | 18篇 |
2002年 | 23篇 |
2001年 | 18篇 |
2000年 | 11篇 |
1999年 | 24篇 |
1998年 | 104篇 |
1997年 | 88篇 |
1996年 | 100篇 |
1995年 | 64篇 |
1994年 | 75篇 |
1993年 | 42篇 |
1992年 | 14篇 |
1991年 | 22篇 |
1990年 | 15篇 |
1989年 | 34篇 |
1988年 | 32篇 |
1987年 | 33篇 |
1986年 | 28篇 |
1985年 | 28篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1966年 | 1篇 |
排序方式: 共有1795条查询结果,搜索用时 8 毫秒
991.
Elisabeth AM Westerbeek Ruurd M van Elburg van den Anemone Berg van den Jolice Berg Jos WR Twisk Willem PF Fetter Harrie N Lafeber 《BMC pediatrics》2008,8(1):1-6
Background
Overweight and obesity are increasing among children all over the world. Socio-economic factors may influence the development of overweight and obesity in childhood, and it has been proposed that breastfeeding may protect against obesity. The aim of our study was to examine the relationship between exclusive breastfeeding and obesity when potential confounders, such as socioeconomic factors, are considered.Methods
The data analyzed was from ABIS (All Babies in Southeast Sweden), a prospective cohort study. All parents with children born between October 1, 1997 and October 1, 1999 in Southeast Sweden (n = 21,700) were asked to participate. Parents were asked to answer periodic questionnaires from the time of the child's birth (n = 16,058) until he/she was five years of age (n = 7,356). Cutoffs for overweight and obesity were defined according to Cole et al, age and gender adjusted. Short-term exclusive breastfeeding was defined as < 4 months of exclusive breastfeeding. Multiple logistic regressions were used to identify variables that predict the child's BMI (Body Mass Index) at five years of age.Results
At five years of age, 12.9% of the children in the study wereoverweight and 4.3% were obese. At the age of three months, 78.4% of the children were being breastfed exclusively. The median exclusive breastfeeding duration was four months. High maternal BMI > 30 (AOR = 1.07; CI = 1.05–1.09; P < 0.001), maternal smoking (AOR = 1.43; CI = 1.05–1.95; P = 0.023) and being a single parent (AOR = 2.10; CI = 1.43–3.09; P < 0.001) were associated with short-term exclusive breastfeeding (less than 4 months). Short-term exclusive breastfeeding was less common if one of the parents had a university degree (Mother: AOR = 0.74; CI = 0.61–0.90; P = 0.003 Father: AOR = 0.73; CI = 0.58–0.92; P = 0.008) or if the father was more than 37 years old (AOR = 0.74; CI = 0.55–0.99; P = 0.045). Short-term exclusive breastfeeding was associated with obesity in five-year-old children (simple logistic regression: OR = 1.44; CI = 1.00–2.07; P = 0.050), but when including other independent factors in the analysis, short-term exclusive breastfeeding did not attain statistical significance.Conclusion
We cannot exclude the possibility that exclusive breastfeeding influences weight development, but it does not seem to protect against obesity at five years of age. 相似文献992.
Gian Luca Baiocchi Sarah Molfino Barbara Frittoli Graziella Pigozzi Federico Gheza Giacomo Gaverini Antonio Tarasconi Chiara Ricci Francesco Bertagna Luigi Grazioli Guido AM Tiberio Nazario Portolani 《World journal of gastroenterology : WJG》2015,21(23):7313-7319
AIM: To analyze the available evidence about the risk of extrapancreatic malignancies and pancreatic ductal adenocarcinoma associated to pancreatic intraductal papillary mucinous tumors (IPMNs).METHODS: A systematic search of literature was undertaken using MEDLINE, EMBASE, Cochrane and Web-of-Science libraries. No limitations for year of publication were considered; preference was given to English papers. All references in selected articles were further screened for additional publications. Both clinical series and Literature reviews were selected. For all eligible studies, a standard data extraction form was filled in and the following data were extracted: study design, number of patients, prevalence of pancreatic cancer and extrapancreatic malignancies in IPMN patients and control groups, if available.RESULTS: A total of 805 abstracts were selected and read; 25 articles were considered pertinent and 17 were chosen for the present systematic review. Eleven monocentric series, 1 multicentric series, 1 case-control study, 1 population-based study and 3 case report were included. A total of 2881 patients were globally analyzed as study group, and the incidence of pancreatic cancer and/or extrapancreatic malignancies ranged from 5% to 52%, with a mean of 28.71%. When a control group was analyzed (6 papers), the same incidence was as low as 9.4%.CONCLUSION: The available Literature is unanimous in claiming IPMNs to be strongly associated with pancreatic and extrapancreatic malignancies. The consequences in IPMNs management are herein discussed. 相似文献
993.
Penelope AM Bunce Shreya Dixit Gayle O Fischer 《The Australasian journal of dermatology》2015,56(1):44-46
You are asked to examine a 68‐year‐old woman with a 3‐year history of multiple bilateral and largely asymptomatic white papules on her labia majora. Based on the history and photographs, what is your diagnosis? 相似文献
994.
F?de la?PortillaEmail author ML?Reyes-Díaz MV?Maestre RM?Jiménez-Rodríguez AM?García-Cabrera JM?Vázquez-Monchul JM?Díaz-Pavón FC?Padillo-Ruiz 《International journal of colorectal disease》2017,32(3):437-440
Background
Faecal incontinence (FI) is both a medical and social problem, with an underestimated incidence. For patients with internal anal sphincter damage, implantation of biomaterial in the anal canal is a recognised treatment option. One such material, Gatekeeper?, has previously shown promising short- and medium-term results without any major complications, including displacement. The main aim of the present study is to assess the degree to which displacement of Gatekeeper prostheses may occur and to determine whether this is associated with patient outcomes.Methods
Seven patients (six females) with a mean age of 55.6 years [50.5–57.2] and a mean FI duration of 6 ± 2 years were prospectively enrolled in the study. Each subject was anaesthetised and underwent implantation of six prostheses in the intersphincteric region, guided by endoanal 3D ultrasound (3D-EAU). Follow-up was performed at post-interventional months 1, 3, and 12 (median 12 ± 4 months), during which data were obtained from a defaecation diary, Wexner scale assessment, anorectal manometry (ARM), 3D-EAU, and a health status and quality of life questionnaire (FIQL).Results
At 3-month follow-up, 3D-EAU revealed displacement of 24/42 prostheses in 5/7 patients. Of these, 15 had migrated to the lower portion and 9 to the upper portion of the anal canal and rectum. Despite this migration, treatment was considered successful in 3/7 patients. In one patient, it was necessary to remove a prosthesis due to spontaneous extrusion.Conclusions
We have shown that displacement of the Gatekeeper? prosthesis occurs, but is not associated with poorer clinical outcomes.995.
The identification of genes inducing resistance to anticancer chemotherapeutic agents and their introduction into hematopoietic cells represents a promising approach to overcome bone marrow toxicity, the limiting factor for most high-dose chemotherapy regimens. Because resistance to cyclophosphamide has been correlated with increased levels of expression of the aldehyde-dehydrogenase (ALDH1) gene in tumor cell lines in vitro, we tested whether ALDH1 overexpression could directly induce cyclophosphamide resistance. We have cloned a full- length human ALDH1 cDNA and used retroviral vectors to transduce it into human (U937) and murine (L1210) hematopoietic cell lines that were then tested for resistance to maphosphamide, an active analogue of cyclophosphamide. Overexpression of the ALDH1 gene resulted in a significant increases in cyclophosphamide resistance in transduced L1210 and U937 cells (50% inhibition concentration [IC50], approximately 13 mumol/L). The resistant phenotype was specifically caused by ALDH1 overexpression as shown by its reversion by disulfiram, a specific ALDH1 inhibitor. ALDH1 transduction into peripheral blood human hematopoietic progenitor cells also led to significant increases (4- to 10-fold; IC50, approximately 3 to 4 mumol/L) in cyclophosphamide resistance in an in vitro colony-forming assay. These findings indicate that ALDH1 overexpression is sufficient to induce cyclophosphamide resistance in vitro and provide a basis for testing the efficacy of ALDH1 gene transduction to protect bone marrow cells from high-dose cyclophosphamide in vivo. 相似文献
996.
997.
AM El-Tawil 《World journal of gastroenterology : WJG》2010,16(28):3475-3477
The incidence of colorectal carcinoma is increasing in young patients, in contrast to the well established wisdom that it is exclusively diagnosed in patients older than 40 years. In this survey, we examined all possible risk factors, and we recommend a number of measures for early detection in young patients who are at risk of developing this malignant tumor. 相似文献
998.
AM El-Tawil 《World journal of gastroenterology : WJG》2010,16(6):659-662
Constipation is a significant manifestation of a number of psychological disorders.Published papers recommend using self-assessment questionnaires for discriminating psychological from non-psychological constipated patients before operating on them but reports from major surveys revealed that general practitioners failed to diagnose 70%of depressed patients using self-assessment questionnaires.Lower circulating concentrations of progesterone,17-hydroxyprogesterone,cortisol,testosterone,androstenedione,and d... 相似文献
999.
1000.
Variations in target volume definition and dose to normal tissue using anatomic versus biological imaging (18F‐FDG‐PET) in the treatment of bone metastases: results from a 3‐arm randomized phase II trial 下载免费PDF全文