全文获取类型
收费全文 | 35789篇 |
免费 | 3559篇 |
国内免费 | 1294篇 |
专业分类
耳鼻咽喉 | 573篇 |
儿科学 | 936篇 |
妇产科学 | 397篇 |
基础医学 | 3573篇 |
口腔科学 | 332篇 |
临床医学 | 4249篇 |
内科学 | 5481篇 |
皮肤病学 | 208篇 |
神经病学 | 7291篇 |
特种医学 | 1145篇 |
外国民族医学 | 1篇 |
外科学 | 4093篇 |
综合类 | 4237篇 |
预防医学 | 2118篇 |
眼科学 | 798篇 |
药学 | 2494篇 |
19篇 | |
中国医学 | 1214篇 |
肿瘤学 | 1483篇 |
出版年
2024年 | 148篇 |
2023年 | 715篇 |
2022年 | 1266篇 |
2021年 | 1694篇 |
2020年 | 1624篇 |
2019年 | 1688篇 |
2018年 | 1693篇 |
2017年 | 1670篇 |
2016年 | 1534篇 |
2015年 | 1419篇 |
2014年 | 2539篇 |
2013年 | 2919篇 |
2012年 | 2163篇 |
2011年 | 2256篇 |
2010年 | 1864篇 |
2009年 | 1852篇 |
2008年 | 1913篇 |
2007年 | 1856篇 |
2006年 | 1574篇 |
2005年 | 1330篇 |
2004年 | 1050篇 |
2003年 | 941篇 |
2002年 | 785篇 |
2001年 | 581篇 |
2000年 | 454篇 |
1999年 | 363篇 |
1998年 | 282篇 |
1997年 | 291篇 |
1996年 | 250篇 |
1995年 | 225篇 |
1994年 | 198篇 |
1993年 | 180篇 |
1992年 | 161篇 |
1991年 | 138篇 |
1990年 | 106篇 |
1989年 | 97篇 |
1988年 | 84篇 |
1987年 | 83篇 |
1986年 | 81篇 |
1985年 | 85篇 |
1984年 | 81篇 |
1983年 | 44篇 |
1982年 | 58篇 |
1981年 | 42篇 |
1980年 | 49篇 |
1979年 | 39篇 |
1978年 | 27篇 |
1977年 | 32篇 |
1976年 | 31篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
《中国现代医生》2020,58(34):60-63
目的 通过检测老年轻度认知障碍(MCI)患者血清瘦素(LEP)、甲状腺激素水平,分析其与局部脑血流量(rCBF)的关系。方法 选择本院收治的128 例老年MCI 患者,另选健康者128 例作为对照组。检测血清LEP、甲状腺激素、大脑各区域rCBF 水平并分析其相关性。结果 老年MCI 组患者左右侧额叶、右侧颞叶、左侧顶叶、左右侧基底节区域脑血流量[(43.81±8.62)mL/(100 g·min)、(43.24±7.93)mL/(100 g·min)、(45.14±6.98)mL/(100 g·min)、(45.86±6.77)mL/(100 g·min)、(67.95±8.52)mL/(100 g·min)、(68.36±8.34)mL/(100 g·min)]低于对照组[(46.39±8.31)mL/(100 g·min)、(46.52±8.56)mL/(100 g·min)、(47.37±7.04)mL/(100 g·min)、(48.25±6.98)mL/(100 g·min)、(70.34±8.96)mL/(100 g·min)、(70.58±8.57)mL/(100 g·min)](P<0.05)。老年MCI 组患者血清LEP、T3、FT3 水平[(4.87±1.56)μg/L、(1.21±0.16)nmol/L、(3.04±0.36)pmol/L]低于对照组[(11.45±3.92)μg/L、(1.68±0.21)nmol/L、(4.82±1.21)pmol/L](P<0.05),TSH 水平为(2.78±0.75)IU/mL,高于对照组的(1.13±0.38)IU/mL(P<0.05)。老年MCI 患者血清LEP 水平与左侧额叶、右侧颞叶、左侧顶叶rCBF 呈正相关(r=0.452、0.537、0.544,P 均<0.05),T3 水平与左侧额叶、右侧颞叶rCBF 呈正相关(r=0.427、0.521,P 均<0.05),FT3 水平与右侧颞叶rCBF 呈正相关(r=0.492,P<0.05),TSH 水平与左侧额叶、右侧颞叶rCBF 呈负相关(r=-0.463、-0.489,P 均<0.05)。结论 老年MCI 患者血清中LEP、T3、FT3 水平降低,TSH 水平升高,且与不同区域rCBF 有相关性,可通过调控脑血管功能影响rCBF 变化水平。 相似文献
42.
43.
44.
45.
《中国现代医生》2020,58(31):37-39+封三
目的 探讨脂蛋白相关磷脂酶A2(Lp-PLA2)、胰岛素样生长因子-1(IGF-1)与老年血管性痴呆(VD)患者认知功能的关系及预测价值。方法 选择2019 年3~6 月在我院接受治疗的VD 患者60 例为研究对象,同时选取同期在我院接受检查的健康者60 例为对照组,比较两组患者的Lp-PLA2、IGF-1、简易智力状态检查量表评分(MMSE)水平;采用Pearson 相关性分析法对Lp-PLA2、IGF-1 与MMSE 评分的相关性进行分析;采用受试者工作曲线(ROC)下面积(AUC)比较Lp-PLA2、IGF-1 对VD 的预测价值。结果 观察组患者的Lp-PLA2 水平明显高于对照组(P<0.05),观察组患者的IGF-1、MMSE 评分明显低于对照组(P<0.05);Lp-PLA2 与MMSE 评分呈负相关性,IGF-1 与MMSE 评分呈正相关性;Lp-PLA2 与IGF-1 诊断VD 的AUC 值分别为0.940、0.954。结论Lp-PLA2 水平越低,IGF-1 水平越高,患者的认知功能越好,且Lp-PLA2、IGF-1 对老年VD 患者均具有较高的预测价值。 相似文献
46.
《Journal of tissue viability》2020,29(4):258-263
ObjectivesThis study aimed to validate the skin temperature on sacral region and vascular attributes as early warning signs of pressure injury.MethodsTotally 415 patients admitted to the adult intensive care unit from August 2018 to April 2019 were prospectively screened. Daily blood pressure and blood glucose affecting vascular attributes and the relative skin temperature of sacral region were measured for 10 consecutive days. Collect the changes of these indicators during the occurrence of pressure injury. The optimal cut-off values of indicators were determined by X-tile analysis. The risk ratios of indicators associated with pressure injury were compared using the Cox proportional hazards regression model.ResultsThere were no obvious interactions among blood pressure, blood glucose and relative skin temperature (P > 0.05). The optimal cutoff value for above indicators was 63.5 mmHg, 9.9 mmol/L and −0.1 °C, respectively. The incidence of pressure injury peaked on the 4th and 5th day after hospitalization when categorizing the patients into low- and high-risk groups according to the cutoff values (P < 0.05). Based on relative skin temperature, patients in the high-risk group were more likely to develop pressure injury (hazard ratio = 6.36, 95% confidence interval = 3.91, 10.36), when compared to the other two indicators of blood pressure and blood glucose.ConclusionStringent skin temperature and vascular attributes measurements were necessary for preventing pressure injury. Nursing measures should be taken according to warning sings to reduce the incidence of pressure injury. 相似文献
47.
A. Caldern‐Larraaga D. L. Vetrano L. Ferrucci S. W. Mercer A. Marengoni G. Onder M. Eriksdotter L. Fratiglioni 《Journal of internal medicine》2019,285(3):255-271
This review discusses the interplay between multimorbidity (i.e. co‐occurrence of more than one chronic health condition in an individual) and functional impairment (i.e. limitations in mobility, strength or cognition that may eventually hamper a person's ability to perform everyday tasks). On the one hand, diseases belonging to common patterns of multimorbidity may interact, curtailing compensatory mechanisms and resulting in physical and cognitive decline. On the other hand, physical and cognitive impairment impact the severity and burden of multimorbidity, contributing to the establishment of a vicious circle. The circle may be further exacerbated by people's reduced ability to cope with treatment and care burden and physicians’ fragmented view of health problems, which cause suboptimal use of health services and reduced quality of life and survival. Thus, the synergistic effects of medical diagnoses and functional status in adults, particularly older adults, emerge as central to assessing their health and care needs. Furthermore, common pathways seem to underlie multimorbidity, functional impairment and their interplay. For example, older age, obesity, involuntary weight loss and sedentarism can accelerate damage accumulation in organs and physiological systems by fostering inflammatory status. Inappropriate use or overuse of specific medications and drug–drug and drug–disease interactions also contribute to the bidirectional association between multimorbidity and functional impairment. Additionally, psychosocial factors such as low socioeconomic status and the direct or indirect effects of negative life events, weak social networks and an external locus of control may underlie the complex interactions between multimorbidity, functional decline and negative outcomes. Identifying modifiable risk factors and pathways common to multimorbidity and functional impairment could aid in the design of interventions to delay, prevent or alleviate age‐related health deterioration; this review provides an overview of knowledge gaps and future directions. 相似文献
48.
《Alzheimer's & dementia》2019,15(12):1507-1515
IntroductionWe estimated the prevalence and correlates of mild cognitive impairment (MCI) among middle-aged and older diverse Hispanics/Latinos.MethodsMiddle-aged and older diverse Hispanics/Latinos enrolled (n = 6377; 50–86 years) in this multisite prospective cohort study were evaluated for MCI using the National Institute on Aging–Alzheimer's Association diagnostic criteria.ResultsThe overall MCI prevalence was 9.8%, which varied between Hispanic/Latino groups. Older age, high cardiovascular disease (CVD) risk, and elevated depressive symptoms were significant correlates of MCI prevalence. Apolipoprotein E4 (APOE) and APOE2 were not significantly associated with MCI.DiscussionMCI prevalence varied among Hispanic/Latino backgrounds, but not as widely as reported in the previous studies. CVD risk and depressive symptoms were associated with increased MCI, whereas APOE4 was not, suggesting alternative etiologies for MCI among diverse Hispanics/Latinos. Our findings suggest that mitigating CVD risk factors may offer important pathways to understanding and reducing MCI and possibly dementia among diverse Hispanics/Latinos. 相似文献
49.
Tau Ming Liew 《Journal of the American Medical Directors Association》2019,20(8):1054.e11-1054.e20
ObjectivesEarly diagnosis of cognitive impairment is increasingly emphasized in the literature to facilitate timely preventive interventions. Although bedside cognitive tests such as the Montreal Cognitive Assessment (MoCA) are widely used for such early diagnostic purposes, they may not have comparable performance to a full neuropsychological battery (FNB) in diagnosing early cognitive impairment. This study investigated whether a small subset of neuropsychological tests can be added on to MoCA to match its performance to that of the FNB in discriminating mild cognitive impairment and dementia (MCI/dementia) from normal cognition.DesignCross-sectional diagnostic study.SettingAlzheimer's Disease Centers across the United States.ParticipantsOlder participants (≥50 years) who completed MoCA and the FNB (N = 9187).MeasuresThe study sample was split into two: the derivation sample (n = 1837) was used to develop a brief neuropsychological battery that best discriminated MCI/dementia (using the best-subset approach with 10-fold cross-validation); while the validation sample (n = 7350) verified its actual performance in discriminating MCI/dementia.ResultsA 3-item neuropsychological battery was identified, comprising MoCA, Benson Complex Figure Recall, and Craft Story 21 Delayed Recall. It had excellent performance in discriminating MCI/dementia from normal cognition (area under the receiver operating characteristic curve [AUROC] 90.0%, 95% confidence interval [CI] 89.2%-90.7%), which was comparable to that of the FNB (AUROC 88.4%, 95% CI 87.6%-89.2%). By contrast, MoCA alone had significantly worse AUROC (86.9%, 95% CI 86.0%-87.7%) than that of the FNB.Conclusions/ImplicationsUsing rigorous methods, this study developed a brief neuropsychological battery that maintained the brevity of a bedside cognitive test, while rivaling the diagnostic performance of an FNB in early cognitive impairment. This brief battery offers a viable alternative when the FNB is needed but cannot be feasibly administered in nonspecialty clinics. It can have a wider health systems effect of improving patients’ access to accurate diagnosis in early cognitive impairment and facilitating timely interventions to delay the progression of cognitive impairment. 相似文献
50.
Tetsuo Shoji Yoshiki Nishizawa 《Therapeutic apheresis and dialysis : official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy》2006,10(Z1):S27-S33
Abstract: The risk of cardiovascular death is high in hemodialysis (HD) patients, and thickening, stiffening and calcification of the arterial wall have been shown as its predictive factors. Activated vitamin D preparations are used for the treatment of secondary hyperparathyroidism in HD patients, but as they increase serum phosphate and calcium concentrations, there is a concern that they promote vascular calcification and, consequently, exacerbate the outcomes. In this article, the effects of vitamin D therapy on survival, cardiac function, arteriosclerosis, immunity, and inflammation are evaluated by reviewing the literature. In HD patients, the risk of death (particularly cardiovascular death) is significantly lower in those treated than in those not treated with vitamin D. Moreover, activated vitamin D improves cardiac function and alleviates cardiac hypertrophy in HD patients. Experimental data in cultured macrophages, vascular smooth muscle cells, and vascular endothelial cells suggest that it has antiatherosclerotic effects. In vivo, the administration of vitamin D improves immune functions and normalizes inflammatory reactions. In HD patients, vascular calcification is related to the dose of calcium carbonate, but its relationship with the administration of vitamin D is not significant. These observations suggest that, contrary to the general concerns, activated vitamin D exerts favorable effects on the cardiovascular system in HD patients as long as it is used in appropriate clinical doses. 相似文献