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   8424篇
  免费   435篇
  国内免费   47篇
耳鼻咽喉   63篇
儿科学   221篇
妇产科学   88篇
基础医学   1090篇
口腔科学   182篇
临床医学   473篇
内科学   2468篇
皮肤病学   70篇
神经病学   623篇
特种医学   357篇
外科学   1323篇
综合类   24篇
预防医学   213篇
眼科学   113篇
药学   581篇
中国医学   11篇
肿瘤学   1006篇
  2023年   65篇
  2022年   129篇
  2021年   201篇
  2020年   111篇
  2019年   146篇
  2018年   188篇
  2017年   166篇
  2016年   177篇
  2015年   218篇
  2014年   241篇
  2013年   328篇
  2012年   502篇
  2011年   594篇
  2010年   343篇
  2009年   310篇
  2008年   514篇
  2007年   557篇
  2006年   545篇
  2005年   523篇
  2004年   537篇
  2003年   546篇
  2002年   484篇
  2001年   115篇
  2000年   93篇
  1999年   113篇
  1998年   103篇
  1997年   94篇
  1996年   62篇
  1995年   64篇
  1994年   52篇
  1993年   60篇
  1992年   78篇
  1991年   69篇
  1990年   71篇
  1989年   55篇
  1988年   63篇
  1987年   40篇
  1986年   35篇
  1985年   47篇
  1984年   31篇
  1983年   30篇
  1982年   22篇
  1981年   20篇
  1980年   21篇
  1979年   20篇
  1978年   30篇
  1977年   13篇
  1974年   12篇
  1971年   9篇
  1968年   7篇
排序方式: 共有8906条查询结果,搜索用时 15 毫秒
991.
992.

Objectives

Among intra/postoperative complications of sinus augmentation from a lateral approach, postoperative infection and implant loss are particularly important because they have irreversible consequences. The purpose of this study was to determine the causes of postoperative infection and implant loss after a lateral approach and to determine the appropriate prophylaxis and therapy.

Materials and methods

In total, 109 patients (121 sinuses, 252 implants) were included in this study. The correlation between postoperative infection and implant loss and clinical variables was assessed using logistic regression analyses.

Results

Postoperative infection and implant loss occurred in 8/121 sinuses (6.6%). Infection had the strongest correlation to preoperative chronic sinusitis (p = 0.007), followed by timing of implant insertion. Implant loss had the strongest correlation to preoperative chronic sinusitis (p = 0.007), followed by sex, diabetes, postoperative use of dentures, and intraoperative perforation of the sinus membrane.

Conclusions

Preoperative chronic sinusitis could be a significant cause of postoperative infection and implant loss when using sinus augmentation from a lateral approach. For appropriate prophylaxis and therapy, it is necessary to diagnose the presence of chronic sinusitis that should be treated with proper methods prior to sinus augmentation.
  相似文献   
993.

Objective

A RANKL-binding peptide, WP9QY (W9), is known to inhibit mouse osteoclastogenesis by stimulating the production of autocrine factors such as bone morphogenetic proteins (BMPs) to induce osteoblast differentiation. In the present study, we investigated whether osteoblastic differentiation is mediated by RANKL signaling.

Methods

The effect of W9 on the differentiation of osteoclasts and osteoblasts was examined in mouse bone-marrow cultures, and in a mouse co-culture system consisting of primary osteoblasts derived from RANKL-deficient or wild-type (WT) newborn mouse calvariae, with WT-derived bone marrow mononuclear cells.

Results

The addition of the W9 peptide to the WT mouse bone-marrow culture simultaneously inhibited RANKL-induced tartrate-resistant acid phosphatase (TRAP)-positive osteoclast differentiation, and stimulated alkaline phosphatase (ALP)-positive osteoblastic calcified nodule formation. RANKL-deficient osteoblasts exhibited weak ALP activity compared to WT osteoblasts. W9 treatment strongly inhibited TRAP-positive osteoclast formation, and stimulated ALP-positive osteoblast differentiation in co-cultures of WT-derived osteoblasts and bone-marrow cells, in the presence of bone-resorbing factors. In contrast, W9 exerted only a weak effect on ALP-positive osteoblast differentiation in co-cultures with RANKL-deficient osteoblasts, even in the presence of the W9 peptide, parathyroid hormone, and/or BMP-2.

Conclusions

The W9 peptide inhibited RANKL-mediated osteoclast formation in osteoblasts. It also directly stimulated osteoblast differentiation, both via RANKL signaling-mediated autocrine factors, and alternative mechanisms.  相似文献   
994.
The incidence of lower urinary tract symptoms, including overactive bladder (OAB), is continuing to rise, and is associated with a negative impact on quality of life and a heavy economic burden. A major risk factor for OAB is advancing age. The etiology of OAB is multifactorial and appears to involve myogenic, neurogenic, and urotheliogenic factors. In this article, we review the strengthening preclinical evidence supporting the contribution of chronic pelvic ischemia to the pathogenesis of OAB. In animal models, chronic ischemia induced by arterial injury and a high‐fat diet upregulates markers of oxidative stress and proinflammatory cytokines in the urothelium and lamina propria, and leads to increased expression of nerve growth factor. These processes result in increased afferent activity and an increased frequency of micturition, reflecting a state of bladder hyperactivity. In severe, prolonged cases, bladder overactivity may develop into underactivity. Antimuscarinic therapies are the mainstay of OAB treatment, but their usefulness is limited by modest efficacy and troublesome side‐effects. Our increasing understanding of the contribution of chronic ischemia to OAB is leading toward novel therapeutic options targeting chronic pelvic ischemia and its morphological, functional, and oxidative consequences. Preclinical trials have demonstrated encouraging results with α1‐adrenoreceptor blockade, phosphodiesterase type 5 inhibition, β3‐adrenoreceptor agonism, free radical scavenging, and stem cell therapy, in preventing morphological, biochemical and functional changes induced by chronic bladder ischemia.  相似文献   
995.
996.
To clarify the clinical status of blood purification therapy (BPT) in critical care in Japan, we conducted a cohort study using data from a nationwide registry of the Japan Society for Blood Purification in Critical Care in 2013. We enrolled 2227 patients treated with BPT (female, 39.1%; mean age, 65.5 ± 12.1 years) in the intensive care units of 43 facilities. Patient characteristics, modes of BPT, and survival rate for each disease were investigated. In total, BPT was performed 3053 times. Continuous renal replacement therapy (CRRT) (57.9%) was the most common mode of BPT, followed by intermittent renal replacement therapy (20.2%) and direct hemoperfusion with the polymyxin B-immobilized fiber column (PMX-DHP) (11.5%). Nafamostat mesilate (84.9%) was most frequently used as the anticoagulant. The 28-day survival rate was 56.8% in all patients. The most common mode for acute kidney injury (AKI) and multiple organ failure was CRRT, while PMX-DHP and CRRT were most common for sepsis. There was no significant difference in survival rates among AKI stages 1–3. Survival rate (38.3%) was significantly lower in patients with acute lung injury (ALI) than in those with multiple organ failure (41.8%) and those with sepsis (46.6%). Multivariate regression analysis revealed that the APACHE II score and the presence of acute ALI and acute hepatic failure were significantly associated with death. This large-scale cohort study showed the clinical status of BPT in Japan. Further investigations are required to clarify the efficacy of BPT for critically ill patients.  相似文献   
997.
The aim of this study was to quantitatively evaluate the function of the cranial diploic and spinal epidural veins as cerebrospinal fluid (CSF) drainage pathways by measuring lipocalin‐type prostaglandin D synthase (PGDS) and cystatin C (CysC) dissolved in the blood of these veins. This was a prospective study involving 51 consecutive patients, 31 males and 20 females, who underwent 41 cranial and 10 spinal surgeries. Intraoperatively, peripheral venous blood and diploic venous blood, or peripheral venous blood and spinal epidural venous blood samples were simultaneously collected and immediately centrifuged. For all samples, dissolved albumin (for reference), PGDS and CysC were measured using an enzyme‐linked immunosorbent assay. The diploic vein/peripheral vein ratios in five cranial locations and epidural vein/peripheral vein ratios were calculated and statistically evaluated for the three biomarkers. For PGDS, the diploic vein/peripheral vein ratio was significantly increased in the frontal (P = 0.011), temporal (P = 0.028), parietal (P = 0.046) and skull base (P = 0.039), while it did not reach statistical significance for CysC. For patients older than 45 years, the diploic vein/peripheral vein ratio for PGDS was significantly decreased in the frontal region (P = 0.028), and the epidural vein/peripheral vein ratio for CysC was significantly decreased (P = 0.014). These results show that the diploic veins constitute CSF drainage pathways with heterogeneous functional intensity at different cranial locations. Compared with the diploic veins, spinal epidural veins seem to drain less CSF. The cranial diploic and spinal epidural veins may jointly function as an alternative, age‐related trans‐dural CSF drainage system.  相似文献   
998.
999.
1000.
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