首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   26902篇
  免费   1488篇
  国内免费   639篇
耳鼻咽喉   168篇
儿科学   1725篇
妇产科学   1465篇
基础医学   3138篇
口腔科学   417篇
临床医学   1794篇
内科学   3981篇
皮肤病学   266篇
神经病学   2568篇
特种医学   377篇
外国民族医学   3篇
外科学   3277篇
综合类   3353篇
现状与发展   4篇
预防医学   1798篇
眼科学   123篇
药学   2483篇
  12篇
中国医学   864篇
肿瘤学   1213篇
  2023年   214篇
  2022年   405篇
  2021年   737篇
  2020年   633篇
  2019年   599篇
  2018年   616篇
  2017年   707篇
  2016年   745篇
  2015年   760篇
  2014年   1292篇
  2013年   1771篇
  2012年   1232篇
  2011年   1506篇
  2010年   1227篇
  2009年   1160篇
  2008年   1265篇
  2007年   1275篇
  2006年   1241篇
  2005年   1077篇
  2004年   896篇
  2003年   858篇
  2002年   745篇
  2001年   678篇
  2000年   643篇
  1999年   513篇
  1998年   447篇
  1997年   459篇
  1996年   419篇
  1995年   408篇
  1994年   402篇
  1993年   347篇
  1992年   345篇
  1991年   345篇
  1990年   349篇
  1989年   280篇
  1988年   228篇
  1987年   201篇
  1986年   219篇
  1985年   283篇
  1984年   249篇
  1983年   149篇
  1982年   194篇
  1981年   163篇
  1980年   137篇
  1979年   122篇
  1978年   107篇
  1977年   94篇
  1976年   70篇
  1975年   50篇
  1973年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Menopause is generally experienced as a biopsychosocial process involving physiological changes, and influenced by a wide range of psychological, social and cultural factors. The loss of ovarian oestrogen production may cause debilitating symptoms, including hot flushes, night sweats, sleep disturbance, vaginal dryness, dyspareunia, bladder dysfunction, loss of libido, and mood changes. Experience of the menopause transition varies widely between individuals, depending on the age of onset, personal health and wellbeing, social context, environment and culture.Hormone Replacement Therapy (HRT) remains the most effective treatment for the management of vasomotor symptoms and vaginal dryness, but has no proven role in the treatment of chronic diseases of ageing. Treatment should be individualized, and for most healthy women aged 50–59 years the risks of HRT are low. An understanding of the pathophysiology of menopausal symptoms and the risks and benefits of both hormonal and non-hormonal treatments assists in the individual management of patients.  相似文献   
2.
3.
        绝经是一个古老的概念,见诸于文献,最早可以追溯到春秋时期中医的重要文献之一《黄帝内经》。其中,《素问·上古天真论》有这样的描述:“女子二七而天葵至,任脉通,太冲脉盛,月事以时下,故有子……七七任脉虚,太冲脉衰少,天葵竭,地道不通,故形坏而无子也。”绝经是卵巢功能衰竭所造成的一种生命现象,从理论上讲,经过长期的进化的洗礼,人体所有的器官和组织,都是维持人体生命活动不可或缺的重要组成部分。时至今日,在不同的流行病学调查中,女性平均绝经年龄仍保持在50岁左右[1-2],可谓亘古未变,而变化的是人类寿命的延长,2018年北京女性预期寿命已经达84.63岁。 浏览更多请关注本刊微信公众号及当期杂志。  相似文献   
4.
《Journal of vascular surgery》2020,71(6):1921-1929
ObjectiveIdentifying biomarkers for abdominal aortic aneurysms (AAA) could prove beneficial in prognosis of AAA and thus the selection for treatment. Microfibrillar-associated protein 4 (MFAP4) is an extracellular matrix protein that is highly expressed in aorta. MFAP4 is involved in several tissue remodeling-related diseases. We aimed to investigate the potential role of plasma MFAP4 (pMFAP4) as a biomarker of AAA.MethodsPlasma samples and data were obtained for 504 male AAA patients and 188 controls in the Viborg Vascular (VIVA) screening trial. The pMFAP4 levels were measured by Alphalisa. The Mann-Whitney U test assessed differences in pMFAP4 levels between the presence and absence of different exposures of interest. The correlation between pMFAP4 and aorta growth rate were investigated through spearman's correlation analysis. Immunohistochemistry and multiple logistic regression adjusted for potential confounders assessed the association between pMFAP4 and AAA. Multiple linear regression assessed the correlation between pMFAP4 and aorta growth rate. Cox regression and competing risk regression were used to investigate the correlation between AAA patients with upper tertile pMFAP4 and the risk of undergoing later surgical repair.ResultsA significant negative correlation between pMFAP4 and aorta growth rate was observed using spearman's correlation analysis (ρ = −0.14; P = .0074). However, this finding did not reach significance when applying multiple linear regression. A tendency of decreased pMFAP4 was observed in AAA using immunohistochemistry. Competing risk regression adjusted for potential confounders indicated that patients with upper tertile pMFAP4 had a hazard ratio of 0.51 (P = .001) for risk of undergoing later surgical repair.ConclusionsHigh levels of pMFAP4 are associated with a decreased likelihood of receiving surgical repair in AAA. This observation warrants confirmation in an independent cohort.  相似文献   
5.
6.
目的:探讨甲状旁腺激素(PTH)对大鼠牵张成骨(DO)过程中ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因表达的影响。方法30只雄性大鼠制备大鼠下颌骨DO模型。随机分5组,每组6只。第1组(只有牵张无PTH),术后8周取材,应用HE染色及微CT检测,以确定成骨情况。第2组(有牵张无PTH),第3组(有牵张有PTH),第4组(无牵张有PTH),第5组(对照组:无牵张无PTH)。2、3、4组及对照组术后1周取材,RT-PCR测定ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因的表达。结果第1组,新骨形成,骨质充满牵张区,骨质连续,大鼠建模成功。RT-PCR检测结果显示,2、3、4组与对照组比较,OPN、COL1、RUNX2、ALP基因表达有明显提高(P<0.05),其中第3组最为明显。ONC、C-FOS、VEGF基因2、3、4组与对照组比较差异无统计学意义(P>0.05)。结论 PTH在 DO 过程中,间歇性给以 PTH的作用只有在牵张期发挥作用,其对 OPN、COL1、RUNX2、ALP基因表达能够获得理想的协同作用。  相似文献   
7.
8.
9.
10.
Background/objectiveObstructive sleep apnea (OSA) is independently associated with dyslipidemia, a surrogate marker of atherosclerosis. Low-density lipoprotein (LDL)-cholesterol is accepted as a major independent risk factor for cardiovascular disease. However, non-high-density lipoprotein (HDL)-cholesterol is a better marker of atherogenic dyslipidemia and recommended as a target of lipid lowering therapy. We aimed to assess the prevalence of atherogenic dyslipidemia, and relationship between OSA severity and serum LDL-cholesterol and non-HDL cholesterol levels in OSA patients.MethodsWe retrospectively evaluated treatment naïve 2361 subjects admitted to the sleep laboratory of a university hospital for polysomnography. All subjects’ lipid profile including total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and non-HDL-cholesterol were measured.ResultsOut of 2361 patients (mean age 49.6 ± 11.9 years; 68.9% male, apnea-hypopnea index 36.6 ± 28.4/h), 185 (7.8%) had no OSA and 2176 (92.2%) had OSA. Atherogenic dyslipidemia prevalence was high (57–66%) in OSA patients, and especially increased in severe OSA compared to other groups (p < 0.05). Though total and LDL-cholesterol did not differ between those with and without OSA, non-HDL-cholesterol (p = 0.020), and triglycerides (p = 0.001) were higher and HDL-cholesterol levels (p = 0.018) were lower in OSA patients than non-OSA. Non-HDL-cholesterol was significantly correlated with OSA severity (p < 0.001) and hypoxia parameters (p < 0.01), whereas LDL-cholesterol showed no correlation.ConclusionsAtherogenic dyslipidemia is highly prevalent and non-HDL-cholesterol levels are significantly increased, predominantly in severe OSA patients. Non-HDL-cholesterol but not LDL-cholesterol, is significantly correlated with OSA severity and hypoxia parameters. Therefore, it could be better to use non-HDL-cholesterol, which is a guideline recommended target of lipid therapy, as a marker of atherosclerotic cardiovascular risk in OSA patients.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号