全文获取类型
收费全文 | 96168篇 |
免费 | 6326篇 |
国内免费 | 2256篇 |
专业分类
耳鼻咽喉 | 302篇 |
儿科学 | 2454篇 |
妇产科学 | 978篇 |
基础医学 | 9256篇 |
口腔科学 | 506篇 |
临床医学 | 13465篇 |
内科学 | 13706篇 |
皮肤病学 | 384篇 |
神经病学 | 9854篇 |
特种医学 | 5378篇 |
外国民族医学 | 4篇 |
外科学 | 6796篇 |
综合类 | 15926篇 |
现状与发展 | 6篇 |
预防医学 | 5284篇 |
眼科学 | 733篇 |
药学 | 9181篇 |
80篇 | |
中国医学 | 7574篇 |
肿瘤学 | 2883篇 |
出版年
2023年 | 1114篇 |
2022年 | 1541篇 |
2021年 | 3050篇 |
2020年 | 3008篇 |
2019年 | 2485篇 |
2018年 | 2473篇 |
2017年 | 2850篇 |
2016年 | 3020篇 |
2015年 | 2910篇 |
2014年 | 5592篇 |
2013年 | 6060篇 |
2012年 | 5264篇 |
2011年 | 5684篇 |
2010年 | 4673篇 |
2009年 | 4384篇 |
2008年 | 4486篇 |
2007年 | 4582篇 |
2006年 | 4231篇 |
2005年 | 3857篇 |
2004年 | 3303篇 |
2003年 | 3016篇 |
2002年 | 2541篇 |
2001年 | 2504篇 |
2000年 | 2075篇 |
1999年 | 1796篇 |
1998年 | 1602篇 |
1997年 | 1684篇 |
1996年 | 1377篇 |
1995年 | 1399篇 |
1994年 | 1317篇 |
1993年 | 995篇 |
1992年 | 1012篇 |
1991年 | 880篇 |
1990年 | 730篇 |
1989年 | 652篇 |
1988年 | 645篇 |
1987年 | 570篇 |
1986年 | 516篇 |
1985年 | 719篇 |
1984年 | 621篇 |
1983年 | 391篇 |
1982年 | 544篇 |
1981年 | 418篇 |
1980年 | 387篇 |
1979年 | 314篇 |
1978年 | 257篇 |
1977年 | 256篇 |
1976年 | 232篇 |
1975年 | 146篇 |
1973年 | 128篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
This systematic review aims to summarize cognitive reserve (CR) evaluation approaches and to examine the role of seven selected modifiable lifestyle factors (diet, smoking, alcohol consumption, physical activity, cognitive leisure activity, sleep, and meditation) in mitigating the impacts of age- or disease-related brain changes on cognition. Eighteen population-based English empirical studies were included. We summarize the study designs and identify three CR models that were broadly used in these studies, including a residual model assessing lifestyle factors in relation to unexplained variance in cognition after accounting for brain markers, a moderation model testing whether lifestyle factors moderate the relationship between brain status and cognition, and a controlling model examining the associations between lifestyle factors and cognition when controlling for brain measures. We also present the findings for the impact of each lifestyle factor. No studies examined diet, sleep, or meditation, and only two studies focused on smoking and alcohol consumption each. Overall, the studies suggest lifestyle activity factors (physical and cognitive leisure activities) may contribute to CR and attenuate the damaging impact of brain changes on cognition. Standardized measurements of lifestyle factors and CR are needed, and mechanisms underlying CR need to be further addressed as well. 相似文献
4.
5.
6.
《Transfusion Clinique et Biologique》2022,29(3):269-272
A delayed haemolytic transfusion reaction (DHTR) encompasses a positive direct antiglobulin test (DAT) developed anytime between 24 hours to 28 days after cessation of transfusion, a positive eluate or a newly identified alloantibody in the plasma or serum along with features of haemolysis in the patient. Routinely, it is expected that with the transfusion of one unit of packed red cells in a patient of average height and weight, the haemoglobin level and hematocrit increase by 1 g/dL and 3% respectively. However, in a patient with DHTR, an inadequate rise of post-transfusion haemoglobin (< 1 g/dL) or rapid fall in haemoglobin back to pre-transfusion levels is observed. Kidd antibodies are particularly known to cause DHTR, maybe alone or in unison with other antibodies. Detection of these alloantibodies is consequential in providing good transfusion support to these patients. These events may be difficult to detect as they may present as varied clinical features or immunological nuisances. In this case series, we have presented three cases of DHTR with special emphasis on their clinical presentations, immunohaematological evaluations, laboratory parameters and the role of proper transfusion support in these patients to avoid further complications. 相似文献
7.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(5):1165-1174
Background and aimsThe extent to which dietary patterns influence the risk of abnormal blood lipids throughout young adulthood remains unclear. The aim was to investigate whether early young adulthood dietary patterns predict the risk of abnormal blood lipids during later young adulthood.Methods and resultsWe used data from a long running birth cohort study in Australia. Western dietary pattern rich in meats, processed foods and high-fat dairy products and prudent pattern rich in fruit, vegetables, fish, nuts, whole grains and low-fat dairy products were derived using principal component analysis at the 21-year follow-up from dietary data obtained using a food frequency questionnaire. After 9-years, fasting blood samples of all participants were collected and their total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterols and triglyceride (TG) levels were measured. Abnormal blood lipids were based on clinical cut-offs for total, LDL and HDL cholesterols, and TG and relative distributions for total:HDL and TG:HDL cholesterols ratios. Log-binomial models were used to estimate risk of each outcome in relation to dietary patterns. Greater adherence to the Western pattern predicted increased risks of high LDL (RR: 1.47; 95%CI: 1.06, 2.03) and TG (1.90; 1.25, 2.86), and high ratios of total:HDL (1.48; 1.00, 2.19) and TG:HDL (1.78; 1.18, 2.70) cholesterols in fully adjusted models. Conversely, a prudent pattern predicted reduced risks of low HDL (0.58; 0.42, 0.78) and high TG (0.66; 0.47, 0.92) and high total:HDL (0.71; 0.51, 0.98) and TG:HDL (0.61; 0.45, 0.84) cholesterols ratios.ConclusionThis is the first prospective study to show greater adherence to unhealthy Western diet predicted increased risks of abnormal blood lipids, whereas healthy prudent diet predicted lower such risks in young adults. Addressing diets in early course may improve cardiovascular health of young adults. 相似文献
8.
9.
10.