全文获取类型
收费全文 | 136038篇 |
免费 | 11828篇 |
国内免费 | 3559篇 |
专业分类
耳鼻咽喉 | 587篇 |
儿科学 | 4010篇 |
妇产科学 | 1377篇 |
基础医学 | 9218篇 |
口腔科学 | 1625篇 |
临床医学 | 18941篇 |
内科学 | 40644篇 |
皮肤病学 | 936篇 |
神经病学 | 3155篇 |
特种医学 | 3021篇 |
外国民族医学 | 2篇 |
外科学 | 13967篇 |
综合类 | 23607篇 |
现状与发展 | 16篇 |
一般理论 | 6篇 |
预防医学 | 6851篇 |
眼科学 | 503篇 |
药学 | 12231篇 |
130篇 | |
中国医学 | 8694篇 |
肿瘤学 | 1904篇 |
出版年
2024年 | 133篇 |
2023年 | 2348篇 |
2022年 | 2861篇 |
2021年 | 5337篇 |
2020年 | 5798篇 |
2019年 | 5196篇 |
2018年 | 4926篇 |
2017年 | 4938篇 |
2016年 | 5007篇 |
2015年 | 5185篇 |
2014年 | 9541篇 |
2013年 | 10393篇 |
2012年 | 7876篇 |
2011年 | 8781篇 |
2010年 | 6918篇 |
2009年 | 6631篇 |
2008年 | 6435篇 |
2007年 | 6587篇 |
2006年 | 5938篇 |
2005年 | 5403篇 |
2004年 | 4324篇 |
2003年 | 3712篇 |
2002年 | 3260篇 |
2001年 | 2930篇 |
2000年 | 2360篇 |
1999年 | 2118篇 |
1998年 | 1712篇 |
1997年 | 1650篇 |
1996年 | 1406篇 |
1995年 | 1424篇 |
1994年 | 1366篇 |
1993年 | 1024篇 |
1992年 | 959篇 |
1991年 | 877篇 |
1990年 | 702篇 |
1989年 | 680篇 |
1988年 | 594篇 |
1987年 | 517篇 |
1986年 | 469篇 |
1985年 | 567篇 |
1984年 | 462篇 |
1983年 | 294篇 |
1982年 | 333篇 |
1981年 | 322篇 |
1980年 | 237篇 |
1979年 | 197篇 |
1978年 | 178篇 |
1977年 | 141篇 |
1976年 | 133篇 |
1975年 | 76篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
92.
93.
D. Medenwald A. Kluttig M.E. Lacruz J. Schumann 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):152-158
Background and Aims
Diet is known to play a decisive role in the development of coronary heart disease (CHD). One factor believed to decrease lifetime risk of CHD is the consumption of omega-3 fatty acids. Yet, conclusive evidence regarding the potential cardioprotective effects of fatty acids is far from being reached. The present study aimed to provide further evidence on the association of serum fatty acid profiles with CHD risk.Methods and Results
The CARdio-vascular Disease, Living and Ageing in Halle study (CARLA study) is an observational cohort study comprising an older adult's general population with a high level of cardiovascular risk factors. In a matched case–control design the serum fatty acid concentrations of 73 subjects with an incident fatal or nonfatal CHD event were compared to 146 controls matched for sex and age. Our data show that the participants of the CARLA study are underserved in unsaturated fatty acids with respect to current dietary recommendations. In addition, the ratio of omega-6 to omega-3 fatty acids was determined to be 8:1 which underlines the consumption of a Western-style diet enriched in omega-6 fatty acids. There were no significant differences in fatty acid patterns between cases and controls. Thus, no clear association of particular serum fatty acid levels with cardiovascular risk was found.Conclusion
Our results support the conclusion that in populations with a homogenous low level of omega-3 polyunsaturated fatty acids consumption, serum fatty acid levels are not associated with CHD risk. 相似文献94.
Louis Anthony Cox Jr. 《Critical reviews in toxicology》2019,49(7):614-635
AbstractCan a single fiber of amphibole asbestos increase the risk of lung cancer or malignant mesothelioma (MM)? Traditional linear no-threshold (LNT) risk assessment assumptions imply that the answer is yes: there is no safe exposure level. This paper draws on recent scientific progress in inflammation biology, especially elucidation of the activation thresholds for NLRP3 inflammasomes and resulting chronic inflammation, to model dose-response relationships for malignant mesothelioma and lung cancer risks caused by asbestos exposures. The modeling integrates a physiologically based pharmacokinetics (PBPK) front end with inflammation-driven two-stage clonal expansion (I-TSCE) models of carcinogenesis to describe how exposure leads to chronic inflammation, which in turn promotes carcinogenesis. Together, the combined PBPK and I-TSCE modeling predict that there are practical thresholds for exposure concentration below which asbestos exposure does not cause chronic inflammation in less than a lifetime, and therefore does not increase chronic inflammation-dependent cancer risks. Quantitative examples using model parameter estimates drawn from the literature suggest that practical thresholds may be within about a factor of 2 of some past exposure levels for some workers. The I-TSCE modeling framework explains previous puzzling aspects of asbestos epidemiology, such as why age at first exposure is a better predictor of lifetime MM risk than exposure duration. It may be a valuable tool for risk analysts when LNT assumptions are not justified due to inflammation response thresholds mediating dose-response relationships. 相似文献
95.
96.
97.
Background
The significance of a positive culture at reimplantation remains an important topic of consideration given the lack of clear metrics for when reimplantation can be performed. The purpose of this study is thus to investigate the (1) association between a positive culture during reimplantation and failure following 2-stage exchange arthroplasty and the (2) influence of prolonged antibiotics on these patients.Methods
We retrospectively reviewed 117 patients undergoing 2-stage exchange hip arthroplasty from 2012 to 2016. Of them, 23 had positive culture during reimplantation and were treated with 2 weeks of intravenous and 4 weeks of oral antibiotics following reimplantation. All patients had a minimum follow-up of 1 year. Logistic regression models were performed to identify association between positive culture and subsequent treatment failure. A meta-analysis was also performed to validate findings. A subgroup analysis was performed to explore whether 6-week antibiotics (oral, intravenous, or both) after reimplantation improved outcomes.Results
A total of 11 studies, which included 141 cases with a positive culture at reimplantation and 784 with negative cultures, were included in the meta-analysis. The pooled data showed a higher risk of failure in patients with a positive culture than those with a negative culture (41.1% vs 14.8%, odds ratio 4.58). The subgroup analysis revealed that 6 weeks of antibiotic administration following reimplantation decreased the odds of reinfection from 9.35 to 3.12. The findings in the retrospective cohort were consistent with those of the meta-analysis; the failure rate was significantly higher in patients with a positive culture than those with negative cultures (26.1% vs 6.4%, P < .001).Conclusion
Six weeks of antibiotics appear to decrease the odds of reinfection after reimplantation. However, despite patients receiving 6 weeks of antibiotics after reimplantation, the risk of reinfection in patients with a positive culture at reimplantation is still more than 3 times higher than those with negative cultures. Further studies are needed to investigate optimal management for such patients. 相似文献98.
Chronic pain in the UK affects up to 43% of the population. The consequences include physical and psychological distress, loss of function, employment, family and social strain and increased utilization of healthcare services. Modern pain management services operate across primary, secondary and tertiary care and incorporate general practitioners, psychologists, physiotherapists, pharmacists, specialist nurses, pain physicians and surgeons. This allows for a coordinated approach to chronic pain, engaging the patient in a structured pathway from conservative measures, through to surgery if necessary. Surgical interventions have been utilized effectively throughout the 20th century for the treatment of a variety of conditions, some of which are now effectively managed with improved pharmacological approaches or novel neuromodulation techniques. Ablative procedures that aim to permanently interrupt the pain pathway still represent the final solution for some conditions, particularly those with cancer associated pain; however, the search for less invasive, less risky measures continues. This is stimulated by an increased understanding of the neurobiology of pain transmission and the physiological changes which occur in persistent pain. 相似文献
99.
《Journal of vascular and interventional radiology : JVIR》2019,30(8):1265-1272
PurposeTo evaluate the safety and efficacy of balloon pulmonary angioplasty (BPA) for nonoperable chronic thromboembolic pulmonary hypertension (CTEPH) patients during the initial experience of a single center.MethodsA total of 18 CTEPH patients (5 with residual pulmonary hypertension after pulmonary endarterectomy) were treated with BPA during the period 2014–2018 and were retrospectively reviewed. Mean age was 61 ± 19 years; 55% were female; mean pulmonary artery pressure was 44 ± 12 mmHg; cardiac output was 4.3 ± 1.0 l/min; and pulmonary vascular resistance was 8.4 ± 3.6 WU. Patients were evaluated by New York Heart Association functional class, 6-minute walk distance, N-terminal pro b-type natriuretic peptide, echocardiography, right heart catheterization, and before and after completions of BPA.ResultsA total of 91 procedures were performed, with a median number of 4 BPA sessions per patient (range, 2–8). There were no deaths or major complications requiring extracorporeal support or (non)invasive ventilation. The most common complication was self-limiting hemoptysis (3%). According to Society of Interventional Radiology classification, 4 mild, 4 moderate, and 1 severe adverse events were noted. Invasive hemodynamics significantly improved, with a cardiac index increase of 15% (P = .0333), decrease of mean pulmonary artery pressure of 30% (P = .0013), and decrease of pulmonary vascular resistance of 45% (P = .0048). Stroke volume index (P = .0171) and pulmonary arterial compliance (P = .0004) were also significantly enhanced.ConclusionsBPA significantly improves cardiopulmonary hemodynamics with an acceptable safety profile. Further studies assessing the long-term efficacy of BPA are required. 相似文献
100.