收费全文 | 1337791篇 |
免费 | 96260篇 |
国内免费 | 2930篇 |
耳鼻咽喉 | 19811篇 |
儿科学 | 40323篇 |
妇产科学 | 38765篇 |
基础医学 | 187799篇 |
口腔科学 | 39946篇 |
临床医学 | 112922篇 |
内科学 | 262989篇 |
皮肤病学 | 30248篇 |
神经病学 | 106558篇 |
特种医学 | 53777篇 |
外国民族医学 | 438篇 |
外科学 | 208883篇 |
综合类 | 31113篇 |
现状与发展 | 6篇 |
一般理论 | 440篇 |
预防医学 | 92202篇 |
眼科学 | 31455篇 |
药学 | 100414篇 |
3篇 | |
中国医学 | 3034篇 |
肿瘤学 | 75855篇 |
2018年 | 11953篇 |
2015年 | 12036篇 |
2014年 | 16913篇 |
2013年 | 25500篇 |
2012年 | 33444篇 |
2011年 | 35262篇 |
2010年 | 20925篇 |
2009年 | 20383篇 |
2008年 | 33798篇 |
2007年 | 36903篇 |
2006年 | 37455篇 |
2005年 | 36176篇 |
2004年 | 35223篇 |
2003年 | 34190篇 |
2002年 | 33707篇 |
2001年 | 63652篇 |
2000年 | 65356篇 |
1999年 | 55420篇 |
1998年 | 14682篇 |
1997年 | 13478篇 |
1996年 | 12952篇 |
1995年 | 12230篇 |
1994年 | 11485篇 |
1992年 | 42782篇 |
1991年 | 41299篇 |
1990年 | 40564篇 |
1989年 | 39562篇 |
1988年 | 36979篇 |
1987年 | 36425篇 |
1986年 | 34905篇 |
1985年 | 33109篇 |
1984年 | 24827篇 |
1983年 | 21055篇 |
1982年 | 12665篇 |
1981年 | 11570篇 |
1980年 | 10777篇 |
1979年 | 23927篇 |
1978年 | 17071篇 |
1977年 | 14837篇 |
1976年 | 13387篇 |
1975年 | 15267篇 |
1974年 | 18086篇 |
1973年 | 17567篇 |
1972年 | 16811篇 |
1971年 | 15721篇 |
1970年 | 14914篇 |
1969年 | 14347篇 |
1968年 | 13460篇 |
1967年 | 12016篇 |
1966年 | 11258篇 |
Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.
Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).
Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity. 相似文献
Background
Current blunt cerebrovascular injury (BCVI) grading grossly differentiates injury characteristics such as luminal stenosis (LS) and aneurysmal disease. The effect of increasing degree of LS beyond the current BCVI grading scale on stroke formation is unknown.Study Design
BCVI over a 3-year period were retrospectively reviewed. To investigate influence of LS beyond the BCVI grading scale within aneurysmal and non-aneurysmal BCVI, grade 2 BCVI were subdivided into BCVI with ≥ 25% and ≤ 50% LS and BCVI with > 50% and ≤ 99% LS. Grade 3 BCVI were subdivided into BCVI with pseudoaneurysm (PSA) without LS and BCVI with PSA and LS. We hypothesized increased LS beyond the current BCVI grade distinctions would be associated with higher rates of stroke formation.Results
312 BCVI were included, of which 140 were carotid BCVI and 172 vertebral BCVI. Sixteen carotid BCVI underwent endovascular intervention (EI) and 19 suffered a stroke. In carotid BCVI stroke rates increased sequentially with BCVI grade except in grade 3. There was a stroke rate of 12% in grade 1 carotid BCVI, 18% in grade 2, 6% in grade 3, and 31% in grade 4. In subgroup analysis for grade 2 carotid BCVI, BCVI with > 50% and ≤ 99% LS had higher rates of stroke (22% vs. 15%, p?=?0.44) than BCVI with ≥ 25% and ≤ 50% LS. In subgroup analysis of grade 3 carotid BCVI, BCVI with PSA and LS had higher rates of stroke (9% vs. 4%, p?=?0.48) than BCVI with PSA without LS. Higher rates of EI in grade 2 carotid BCVI with > 50% and ≤ 99% LS (22% vs. 5%, p?=?0.14) and grade 3 carotid BCVI with PSA and LS (35% vs. 4%, p?=?0.01) were noted in subgroup analysis.Conclusion
Higher percentage LS beyond the currently used BCVI grading scale has a non-significantly increased rate of stroke in both aneurysmal and non-aneurysmal BCVI. Grade 3 BCVI with PSA and LS seems to be a high-risk subgroup. Use of EI confounds modern measurement of stroke risk in higher LS BCVI. 相似文献Methods: This Case-Control study was carried out on 96 patients with esophageal cancer and 187 controls. Controls were matched to cases by age and sex. Data were collected through structured interview. Data were analyzed by using chi-square test, T-test and logistic regression, in Stata software version 12.
Results: Our findings show Hookah smoking [OR = 6.1(CI95%:1.2–13.1)] and opium consumption [OR = 2.1(CI95%:1.2–3.5)] were associated with esophageal cancer. Cigarette and pipe smoking, age of onset of smoking, duration of smoking, number of smoking per day, leaving history of smoking, years of leaving smoking, drug withdrawal, number of times of drug withdrawal, a history of drug relapse, alcohol consumption and alcohol dose–response were not related to esophageal cancer.
Conclusion: According to our results, hookah smoking and opium consumption enhance the risk of esophageal cancer in North Khorasan of Iran. We suggest appropriate planning to prevent the esophageal cancer in this district. 相似文献