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   7916篇
  免费   427篇
  国内免费   73篇
耳鼻咽喉   53篇
儿科学   173篇
妇产科学   643篇
基础医学   892篇
口腔科学   120篇
临床医学   894篇
内科学   1631篇
皮肤病学   78篇
神经病学   522篇
特种医学   240篇
外科学   1058篇
综合类   176篇
预防医学   401篇
眼科学   72篇
药学   584篇
中国医学   114篇
肿瘤学   765篇
  2023年   38篇
  2022年   95篇
  2021年   174篇
  2020年   92篇
  2019年   145篇
  2018年   244篇
  2017年   166篇
  2016年   155篇
  2015年   206篇
  2014年   241篇
  2013年   378篇
  2012年   568篇
  2011年   578篇
  2010年   370篇
  2009年   309篇
  2008年   492篇
  2007年   538篇
  2006年   536篇
  2005年   435篇
  2004年   378篇
  2003年   317篇
  2002年   310篇
  2001年   262篇
  2000年   271篇
  1999年   201篇
  1998年   53篇
  1997年   55篇
  1996年   57篇
  1995年   31篇
  1994年   44篇
  1993年   25篇
  1992年   128篇
  1991年   91篇
  1990年   67篇
  1989年   42篇
  1988年   46篇
  1987年   44篇
  1986年   44篇
  1985年   27篇
  1984年   34篇
  1983年   11篇
  1982年   7篇
  1981年   13篇
  1980年   6篇
  1979年   15篇
  1977年   6篇
  1976年   5篇
  1973年   7篇
  1972年   7篇
  1971年   10篇
排序方式: 共有8416条查询结果,搜索用时 15 毫秒
211.
212.

Objective

The incidence of chronic kidney disease (CKD) is on the rise. CKD patients are at high risk of cardiovascular (CVD) and all-cause mortality. CKD patients have several endocrine disorders, including low levels of dehydroepiandrosterone sulfate (DHEA-S). In the general population, low levels of DHEA-S are associated with high CVD and all-cause mortality. The aim of this study was to analyze the prognostic value of plasma DHEA-S on the survival of CKD patients on hemodialysis.

Method

This was a single-center prospective cohort study on two hundred CKD patients on hemodialysis, which assessed the prognostic value of plasma DHEA-S on their survival.

Result

We found that plasma DHEA-S levels were negatively associated with age, and positively associated with dialysis duration and plasma creatinine, albumin, and phosphate levels in hemodialysis men. Elderly patients with co-morbidities (i.e. diabetes mellitus, congestive heart failure, and chronic obstructive pulmonary disease), poorer fluid control which was evaluated by higher cardiothoracic ratio, and low plasma creatinine and albumin levels seemed to have poor prognosis in hemodialysis men. Furthermore, low plasma DHEA-S levels were significantly associated with CVD-related [hazard ratio (HR) = 3.877; P = 0.021], non-CVD-related (HR = 3.522; P = 0.016), and all-cause mortality (HR = 3.667; P = 0.001) in hemodialysis men. But low plasma DHEA-S levels were not significantly associated with CVD-related, non-CVD-related, and all-cause mortality in hemodialysis women. Multivariate Cox regression analysis suggested that low plasma DHEA-S levels are significantly and independently associated with all-cause mortality in hemodialysis men (HR = 2.933; P = 0.033).

Conclusion

The study suggested that low plasma DHEA-S was independently and significantly associated with all-cause mortality in CKD hemodialysis men.  相似文献   
213.
A 42-year-old female presented with chest pain, noted to have systolic and diastolic murmurs on physical examination and left ventricular hypertrophy on the electrocardiogram. Echocardiography with contrast enhancement revealed hypertrophic cardiomyopathy (HCM) with apical aneurysm and mid left ventricular cavity obstruction. Doppler interrogation showed continuous systolic and diastolic flow from the apex to left ventricle (LV) with a transient deceleration giving rise to a notched pattern. Myocardial ischemia of the apex was demonstrated on adenosine nuclear scintigraphy without epicardial coronary obstruction on angiography. This case demonstrates a novel Doppler pattern with continuous apex to LV flow in HCM in the setting of apical ischemia that may account for the formation of the aneurysm.  相似文献   
214.
Abstract: Idiopathic membranous nephropathy (MN), an autoimmune‐mediated glomerulonephritis, is one of the most common causes of nephrotic syndrome in adults. Therapeutic agents for MN remain ill defined. We assessed the efficacy of melatonin therapy for MN. Experimental murine MN was induced with cationic bovine serum albumin, and the mice were immediately administered 20 mg/kg melatonin or phosphate‐buffered saline subcutaneously once a day. Disease severity was verified by examining serum and urine metabolic profiles and renal histopathology. The expression of cytokines and oxidative stress markers, cell apoptosis, and the associated mechanisms were also determined. Mice treated with melatonin displayed a significant reduction in proteinuria and a marked amelioration of glomerular lesions, with attenuated immunocomplex deposition. The subpopulations of T cells were not altered, but the CD19+ B‐cell subpopulation was significantly reduced in the MN mice treated with melatonin. The expression of cytokine mRNAs in splenocytes indicated that melatonin reduced the expression of proinflammatory cytokines and increased the expression of anti‐inflammatory cytokines (interleukin 10). The production of reactive oxygen species and TUNEL‐positive apoptotic cells in the kidney were also significantly reduced in the melatonin‐treated MN mice. Melatonin also upregulated heme oxygenase 1 (HO1) and ameliorated MN. The blockade of HO1 expression with SnPP, a HO1 inhibitor, attenuated HO1 induction by melatonin and thus mitigated its renoprotective effects during MN. Our results suggest that melatonin treatment ameliorates experimental MN via multiple pathways, including by its antioxidative, antiapoptotic, and immunomodulatory effects. Melatonin should be considered a potential therapeutic intervention for MN in the future.  相似文献   
215.
216.
217.
With good hemostatic ability, the end-firing continuous-wave diode laser at 980 nm was used to enucleate the prostate (DiLEP) for the treatment of benign prostatic obstruction (BPO). The study compared the patients' demographics and surgical outcomes between DiLEP and transurethral resection of the prostate (TURP). Patients with significant BPO and a total prostatic weight of 40 g or more who had undergone DiLEP (n = 74) or TURP (n = 52) during the same period at our hospital were enrolled for analysis. DiLEP was performed by a single surgeon (Yang), and TURP by three surgeons (Yang, Hsieh and Chang). The 4-U incision technique was developed for DiLEP. The diode laser ensured bloodless incision followed by blunt dissection using the resectoscope and laser fiber as an 'index finger' to enucleate the prostate. To prevent unexpected deep thermal damage, the power of the laser was set at 80 W and the laser beam was directed towards the bladder neck and not towards the prostatic capsule. Demographic data and perioperative parameters were comparable between the two groups, except that DiLEP resulted in a significantly lower drop in hemoglobin level (0.9 ± 1.0 vs. 1.6 ± 2.4 g/dl, p = 0.03), shorter catheterization time (41.2 ± 19.9 vs. 67.7 ± 33.3 h, p = 0.01), and shorter postoperative stay (2.9 ± 1.9 vs. 4.1 ± 6.2 days, p = 00.01). Delayed postoperative sloughing of necrotic tissue was not observed in the DiLEP group. Improvements in voiding parameters were comparable between the groups, and were sustained during a follow-up of up to 1 year. DiLEP provided better hemostasis than TURP as evidenced by less blood loss. The role of DiLEP treating BPO requires further investigation.  相似文献   
218.
This study evaluates prevalence of hypertension in 1996 and 2006, and examines the relationship between hypertension and weight of Taiwanese young adolescents. Two cross-sectional surveys, administered in 1996 and 2006, to junior-high school in Taipei were included. Anthropometric and blood pressure were measured using standard methods, and structured questionnaire was used to collect personal history and lifestyle characteristics. Overweight and obesity are defined based on Taiwan's Department of Health criteria and bases pre-hypertension and hypertension on the 90th and 95th percentile distribution of blood pressure of the population of both surveys. The prevalence of pre-hypertension in Taiwan between 1996 and 2006 increased from 12.0 to 14.4% for boys and decreased from 9.5 to 9.4% for girls. Hypertension increased from 22.8-29.7% and 12.5-20.7% for both boys and girls, respectively. In 1996, compared with normal young adolescents, the risk of hypertension for overweight was 1.8 times higher for boys and 3.4 times for girls. However, the risk of hypertension for overweight in 2006 was 1.7 times higher for boys and 1.5 times higher for girls compared with normal. Every unit increment of body mass index and waist circumference was associated with 17-27% and 6-11% risk of hypertension in both genders in 1996, and was associated with 9-13% and 4% risk of hypertension among young adolescents in 2006, respectively. The prevalence of hypertension has increased significantly in young adolescents, especially for overweight. It is necessary to enrol young adolescents in weight management programs to prevent hypertension-related co-morbidities.  相似文献   
219.
220.
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