收费全文 | 23983篇 |
免费 | 2533篇 |
国内免费 | 403篇 |
耳鼻咽喉 | 71篇 |
儿科学 | 518篇 |
妇产科学 | 497篇 |
基础医学 | 2269篇 |
口腔科学 | 123篇 |
临床医学 | 3551篇 |
内科学 | 1777篇 |
皮肤病学 | 109篇 |
神经病学 | 8503篇 |
特种医学 | 180篇 |
外科学 | 859篇 |
综合类 | 2532篇 |
现状与发展 | 2篇 |
一般理论 | 4篇 |
预防医学 | 1517篇 |
眼科学 | 59篇 |
药学 | 2098篇 |
30篇 | |
中国医学 | 1568篇 |
肿瘤学 | 652篇 |
2024年 | 49篇 |
2023年 | 511篇 |
2022年 | 478篇 |
2021年 | 1008篇 |
2020年 | 1158篇 |
2019年 | 1073篇 |
2018年 | 1029篇 |
2017年 | 1117篇 |
2016年 | 1152篇 |
2015年 | 1002篇 |
2014年 | 1549篇 |
2013年 | 2276篇 |
2012年 | 1413篇 |
2011年 | 1425篇 |
2010年 | 1260篇 |
2009年 | 1196篇 |
2008年 | 1175篇 |
2007年 | 1138篇 |
2006年 | 998篇 |
2005年 | 843篇 |
2004年 | 671篇 |
2003年 | 636篇 |
2002年 | 546篇 |
2001年 | 420篇 |
2000年 | 291篇 |
1999年 | 204篇 |
1998年 | 177篇 |
1997年 | 180篇 |
1996年 | 121篇 |
1995年 | 162篇 |
1994年 | 171篇 |
1993年 | 131篇 |
1992年 | 149篇 |
1991年 | 119篇 |
1990年 | 101篇 |
1989年 | 118篇 |
1988年 | 107篇 |
1987年 | 116篇 |
1986年 | 93篇 |
1985年 | 115篇 |
1984年 | 83篇 |
1983年 | 62篇 |
1982年 | 64篇 |
1981年 | 50篇 |
1980年 | 43篇 |
1979年 | 32篇 |
1978年 | 22篇 |
1977年 | 25篇 |
1976年 | 18篇 |
1975年 | 15篇 |
Methods: Male Wistar rats were suckled in litters with six or 12 pups (L6 and L12 groups). Animals swam at postnatal days (P) 8–23, or P60–P75 (early-exercised or late-exercised groups, respectively), or remained no-exercised. Behavioral tests (open field – OF and object recognition – OR) were conducted between P77 and P80. Between P90 and P120, ECoG was recorded for 2 hours. After this ‘baseline’ recording, CSD was elicited every 30 minutes over the course of 2 hours.
Results: Early swimming enhanced the number of entries and the percentage of time in the OF-center (P?<?0.05). In animals that swam later, this effect occurred in the L6 group only. Compared to the corresponding sedentary groups, OR-test showed a better memory in the L6 early exercised rats, and a worse memory in all other groups (P?<?0.05). In comparison to baseline values, ECoG amplitudes after CSD increased 14–43% for all groups (P?<?0.05). In the L6 condition, early swimming and late swimming, respectively, reduced and enhanced the magnitude of the post-CSD ECoG potentiation in comparison with the corresponding L6 no-exercised groups (P?<?0.05).
Discussion: Our data suggest a differential effect of early- and late-exercise on the behavioral and electrophysiological parameters, suggesting an interaction between the age of exercise and the nutritional status during lactation. 相似文献
Methods: 3,742 individuals with T1D age ≥50 were followed for dementia from 1/1/96-9/30/2015. Depression, dementia, and comorbidities were abstracted from electronic medical records. Cox proportional hazard models estimated the association between depression and dementia adjusting for demographics, glycosylated hemoglobin, severe dysglycemic epidsodes, stroke, heart disease, nephropathy, and end stage renal disease. The cumulative incidence of dementia by depression was estimated conditional on survival dementia-free to age 55.
Results: Five percent (N = 182) were diagnosed with dementia and 20% had baseline depression. Depression was associated with a 72% increase in dementia (fully adjusted HR = 1.72; 95% CI:1.12-2.65). The 25-year cumulative incidence of dementia was more than double for those with versus without depression (27% vs. 12%).
Conclusions: For people with T1D, depression significantly increases dementia risk. Given the pervasiveness of depression in T1D, this has major implications for successful aging in this population recently living to old age. 相似文献
Methods: The study included 314 subjects (42 bipolar-BD patients; 21 manics and 21 depressives, 68 unipolar-UD, and 204 normal controls-NC). Analysis of Covariance (ANCOVA) and the calculation of the Relative Risk (RR) and the Odds Ratio (OR) were used for the analysis.
Results: Paternal age differed between NC and UD patients (29.42?±?6.07 vs. 32.12?±?5.54; p?=?.01) and manics (29.42?±?6.07 vs. 35.00?±?5.75; p?=?.001) and maternal age between NC and manics (25.46?±?4.52 vs. 31.43?±?4.75; p?<?.001) and manic and UD (31.43?±?4.75 vs. 26.75?±?6.03; p?=?.002). The RR and OR values suggested that advanced parental age constitutes a risk factor for the development of mood disorders.
Conclusions: In a non-dose dependent and gender-independent, advanced parental age constitutes a risk factor for the development of BD with index episode of mania (probably manic predominant polarity); only advanced paternal age constitutes a risk factor for the development of UD and BD with index episode of depression (probably depressive predominant polarity). This is the first study suggesting differential effect of advanced parental age depending on predominant polarity of BD. 相似文献
Method: This is a randomized study registered in Chinese Clinical Trial Registry (ChiCTR-IOR-17011289). Eighty rural left-behind elderly people who had a Geriatric Depression Scale (GDS) score between 11 and 25 were randomly assigned to the intervention (n?=?40) and control group (n?=?40). The intervention group received both MBAT and regular treatment for 8 weeks while the control group received regular treatment. Both groups were assessed with the GDS, Beck Anxiety Inventory (BAI), and Oxford Happiness Questionnaire (OHQ) at baseline, immediately post-intervention, and at 3 months post-intervention.
Results: There were a total of 73 participants that completed the intervention. The scores of GDS and BAI decreased significantly, but the scores of OHQ increased significantly in the intervention group after 8 sessions of MBAT (P?<?.01). The reduction in depression symptoms after the intervention was maintained at the 3-month follow-up. Significant differences in GDS, BAI, and OHQ scores were observed between the intervention group and the control group (P?<?.01).
Conclusion: MBAT produced a significantly greater reduction in depressive symptoms than regular care in rural left-behind elderly.
Clinical or methodological significance of this article: A modified behavioral activation (BA) psychotherapy can significantly reduce the recurrence and seriousness of depression symptoms in the left-behind elderly with mild to moderate depression. This study also suggests that further study of the MBAT as an intervention will provide a direction for the management of mental health in rural left-behind elders. 相似文献