全文获取类型
收费全文 | 25153篇 |
免费 | 1874篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 1037篇 |
妇产科学 | 862篇 |
基础医学 | 2912篇 |
口腔科学 | 322篇 |
临床医学 | 4130篇 |
内科学 | 4624篇 |
皮肤病学 | 447篇 |
神经病学 | 2331篇 |
特种医学 | 445篇 |
外科学 | 2104篇 |
综合类 | 343篇 |
一般理论 | 29篇 |
预防医学 | 3650篇 |
眼科学 | 364篇 |
药学 | 1581篇 |
中国医学 | 35篇 |
肿瘤学 | 1737篇 |
出版年
2023年 | 176篇 |
2022年 | 93篇 |
2021年 | 351篇 |
2020年 | 350篇 |
2019年 | 564篇 |
2018年 | 638篇 |
2017年 | 514篇 |
2016年 | 563篇 |
2015年 | 621篇 |
2014年 | 852篇 |
2013年 | 1342篇 |
2012年 | 1991篇 |
2011年 | 1963篇 |
2010年 | 1107篇 |
2009年 | 1036篇 |
2008年 | 1673篇 |
2007年 | 1837篇 |
2006年 | 1713篇 |
2005年 | 1763篇 |
2004年 | 1674篇 |
2003年 | 1511篇 |
2002年 | 1458篇 |
2001年 | 233篇 |
2000年 | 169篇 |
1999年 | 191篇 |
1998年 | 237篇 |
1997年 | 168篇 |
1996年 | 153篇 |
1995年 | 187篇 |
1994年 | 162篇 |
1993年 | 139篇 |
1992年 | 113篇 |
1991年 | 96篇 |
1990年 | 111篇 |
1989年 | 95篇 |
1988年 | 75篇 |
1987年 | 78篇 |
1986年 | 76篇 |
1985年 | 90篇 |
1984年 | 101篇 |
1983年 | 67篇 |
1982年 | 89篇 |
1981年 | 75篇 |
1980年 | 70篇 |
1979年 | 51篇 |
1978年 | 55篇 |
1977年 | 45篇 |
1975年 | 36篇 |
1973年 | 27篇 |
1972年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
1.
2.
3.
Ora Paltiel Stanley Lemeshow Gary S. Phillips Gabriella Tikellis Martha S. Linet Anne-Louise Ponsonby Per Magnus Siri E. Håberg Sjurdur F. Olsen Charlotta Granström Mark Klebanoff Jean Golding Zdenko Herceg Akram Ghantous Jane Elizabeth Hirst Arndt Borkhardt Mary H. Ward Signe Holst Søegaard Terence Dwyer 《International journal of cancer. Journal international du cancer》2019,144(1):26-33
The “delayed infection hypothesis” states that a paucity of infections in early childhood may lead to higher risks of childhood leukemia (CL), especially acute lymphoblastic leukemia (ALL). Using prospectively collected data from six population-based birth cohorts we studied the association between birth order (a proxy for pathogen exposure) and CL. We explored whether other birth or parental characteristics modify this association. With 2.2 × 106 person-years of follow-up, 185 CL and 136 ALL cases were ascertained. In Cox proportional hazards models, increasing birth order (continuous) was inversely associated with CL and ALL; hazard ratios (HR) = 0.88, 95% confidence interval (CI): (0.77–0.99) and 0.85: (0.73–0.99), respectively. Being later-born was associated with similarly reduced hazards of CL and ALL compared to being first-born; HRs = 0.78: 95% CI: 0.58–1.05 and 0.73: 0.52–1.03, respectively. Successive birth orders were associated with decreased CL and ALL risks (P for trend 0.047 and 0.055, respectively). Multivariable adjustment somewhat attenuated the associations. We found statistically significant and borderline interactions between birth weight (p = 0.024) and paternal age (p = 0.067), respectively, in associations between being later-born and CL, with the lowest risk observed for children born at <3 kg with fathers aged 35+ (HR = 0.18, 95% CI: 0.06–0.50). Our study strengthens the theory that increasing birth order confers protection against CL and ALL risks, but suggests that this association may be modified among subsets of children with different characteristics, notably advanced paternal age and lower birth weight. It is unclear whether these findings can be explained solely by infectious exposures. 相似文献
4.
Jessica Mumford Michael Kohn Julie Briody Jane Miskovic-Wheatley Sloane Madden Simon Clarke Andrew Biggin Aaron Schindeler Craig Munns 《The Journal of adolescent health》2019,64(3):305-310
Purpose
Anorexia nervosa (AN) is a chronic and life-threatening eating disorder that can have a considerable negative impact on the growing skeleton. We hypothesized that the long-term impact on bone health may persist even after normalization of body weight.Methods
41 females (mean age 21.2 ± 2.9 years) with a history of adolescent-onset AN attended a follow-up bone health assessment at 5 years (T5, n?=?28) or 10 years (T10, n?=?13) after their first AN-related hospital admission. Assessment included dual-energy x-ray absorptiometry measurements of the total body, lumbar spine, and proximal femur, peripheral quantitative computed tomography at the radius and tibia, anthropometric measurements, serum biochemistry, fracture history, and a patient questionnaire.Results
A recovery in body weight and BMI was seen for both the T5 and T10 cohorts (BMI at intake 16.6, BMI at T5-T10 21.2-21.3). Dual-energy x-ray absorptiometry body composition indicated a recovery of fat mass and lean tissue mass. Total BMD was unaffected, but reductions were seen at the femoral neck and arms. Peripheral quantitative computed tomography showed reduced trabecular and cortical bone in the radius, and cortical thinning in the tibia. AN patients showed a statistically significant reduction in measures of radiographic bone health at follow up, although not to a degree that necessitated clinical intervention. Serum insulin-like growth factor 1 was also positively correlated with total BMD and BMC measures. While fracture risk was not increased, a subset of participants (8%) showed multiple (>4) fractures.Conclusion
A longitudinal study of adolescent AN showed persisting negative effects on bone health. 相似文献5.
Chi Andrew S. Tarapore Rohinton S. Hall Matthew D. Shonka Nicole Gardner Sharon Umemura Yoshie Sumrall Ashley Khatib Ziad Mueller Sabine Kline Cassie Zaky Wafik Khatua Soumen Weathers Shiao-Pei Odia Yazmin Niazi Toba N. Daghistani Doured Cherrick Irene Korones David Karajannis Matthias A. Kong Xiao-Tang Minturn Jane Waanders Angela Arillaga-Romany Isabel Batchelor Tracy Wen Patrick Y. Merdinger Krystal Schalop Lee Stogniew Martin Allen Joshua E. Oster Wolfgang Mehta Minesh P. 《Journal of neuro-oncology》2019,144(1):97-105
Journal of Neuro-Oncology - Smoking is agreed to be a major health risk factor, but it is debated whether it has an influence on perioperative adverse events (AEs) in elective cranial tumor... 相似文献
6.
Roger Blanks Andrea Burón Pust Rupert Alison Emily He Isobel Barnes Julietta Patnick Gillian K Reeves Sarah Floud Valerie Beral Jane Green 《International journal of cancer. Journal international du cancer》2019,145(3):728-734
Faecal occult blood (FOB) - based screening programmes for colorectal cancer detect about half of all cancers. Little is known about individual health behavioural characteristics which may be associated with screen-detected and interval cancers. Electronic linkage between the UK National Health Service Bowel Cancer Screening Programme (BCSP) in England, cancer registration and other national health records, and a large on-going UK cohort, the Million Women Study, provided data on 628,976 women screened using a guaiac-FOB test (gFOBt) between 2006 and 2012. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated by logistic and Cox regression for associations between individual lifestyle factors and risk of colorectal tumours. Among screened women, 766 were diagnosed with screen-detected colorectal cancer registered within 2 years after a positive gFOBt result, and 749 with interval colorectal cancers registered within 2 years after a negative gFOBt result. Current smoking was significantly associated with risk of interval cancer (RR 1.64, 95%CI 1.35–1.99) but not with risk of screen-detected cancer (RR 1.03, 0.84–1.28), and was the only factor of eight examined to show a significant difference in risk between interval and screen-detected cancers (p for difference, 0.003). Compared to screen-detected cancers, interval cancers tended to be sited in the proximal colon or rectum, to be of non-adenocarcinoma morphology, and to be of higher stage. 相似文献
7.
Felicity Jane Pool Miranda Lynette Siemienowicz 《Journal of Medical Imaging and Radiation Oncology》2019,63(1):7-14
The Royal Australian and New Zealand College of Radiologists (RANZCR) Radiology Written Report Guideline was first issued in 2011. A survey‐based consultation of clinical radiology members of the college in 2015 found that the vast majority of 235 respondents supported all components of the guideline. Since the original guideline was developed, considerable new research has been published about radiology reporting, particularly regarding structured/template reports. In 2016/17 a RANZCR working group used the consultation results, stakeholder feedback and recent research to develop revised guidelines. This article outlines the consultation survey results and guideline revision process as well as some of the supporting evidence from the literature. 相似文献
8.
Objectives
The primary objective of this study was to compare the 12-month continuation rate for women who self-injected subcutaneous depot-medroxyprogesterone acetate (DMPA-SC) with that for women receiving intramuscular depot-medroxyprogesterone acetate (DMPA-IM) from a provider. This research contributes to the broader goal of identifying solutions to support women to use contraception for their full desired duration.Study design
Participants were clients from 13 clinics in the Dakar and Thiés regions of Senegal who had decided to use injectable contraception prior to enrollment. They chose self-injection of DMPA-SC or provider administration of DMPA-IM. Self-injectors were trained and given three units of DMPA-SC. The provider-injected group received DMPA-IM and returned to the clinics for future injections. We interviewed participants at baseline and after the second, third and fourth injections (the equivalent of 12?months of contraceptive coverage). We employed Kaplan–Meier methods to estimate continuation probabilities, with a log-rank test to compare differences between groups. A multivariate Cox regression identified factors correlated with discontinuation.Results
The 12-month continuation rate for 650 women self-injecting DMPA-SC was 80.2%, while that for 649 women receiving DMPA-IM from a provider was 70.4% (p<.01). The difference in continuation between self-injectors and those receiving DMPA from a provider remained significant in a multivariate Cox regression model. The primary reason for discontinuation in both groups (44.7% self-injected; 44.5% provider-injected) was forgetting to reinject or reinjecting late. Fewer women reported side effects in the self-injection group than in the provider-administered group.Conclusions
The higher 12-month continuation rate for women self-injecting DMPA-SC relative to provider-administered DMPA-IM suggests that self-injection may help prevent pregnancy more consistently and continuously.Implications
Discontinuation of injectable contraception among women wishing to avoid pregnancy may increase unmet need in francophone West Africa. This study showed higher 12-month continuation rates for women who self-injected DMPA-SC, suggesting that this delivery method may improve injectable continuation. 相似文献9.
My mind is made up: Cancer concern and women’s preferences for contralateral prophylactic mastectomy
Richard De Abreu Loureno Marion Haas Jane Hall Kim Parish Domini Stuart Rosalie Viney 《European journal of cancer care》2019,28(4)
The fear of cancer recurrence is cited as a motivator of women's preferences between routine monitoring and contralateral prophylactic mastectomy (CPM) as methods of managing ongoing breast cancer risk. We conducted a discrete choice experiment among a general community sample of women who completed 12 hypothetical choices between routine monitoring and CPM described by aspects of treatment efficacy, safety, cost and involvement in decision‐making. Respondents also completed a modified cancer worry question to assess cancer concern. Approximately 57.5% of 464 women always chose one option, typically routine monitoring. The majority (71.5%) reported being concerned about cancer recurrence when completing choice tasks. Latent class analysis identified three groups: preferred routine monitoring; preferred CPM; and “traders” (willing to swap between options). Among traders, women were less likely to choose an option associated with higher risk of recurrence. Women were more likely to choose options associated with less‐intrusive monitoring methods and where they were involved in decision‐making. Women concerned about cancer recurrence were more likely to choose CPM over monitoring. This study shows that women's preferences about how to manage breast cancer recurrence risk reflect the importance of the associated health effects, experience of care and attitudes to cancer recurrence. 相似文献