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   2256篇
  免费   80篇
  国内免费   26篇
耳鼻咽喉   16篇
儿科学   46篇
妇产科学   80篇
基础医学   292篇
口腔科学   42篇
临床医学   166篇
内科学   503篇
皮肤病学   41篇
神经病学   122篇
特种医学   63篇
外科学   464篇
综合类   18篇
预防医学   26篇
眼科学   65篇
药学   133篇
中国医学   4篇
肿瘤学   281篇
  2023年   13篇
  2022年   36篇
  2021年   54篇
  2020年   26篇
  2019年   35篇
  2018年   48篇
  2017年   40篇
  2016年   38篇
  2015年   44篇
  2014年   59篇
  2013年   78篇
  2012年   147篇
  2011年   177篇
  2010年   110篇
  2009年   101篇
  2008年   134篇
  2007年   130篇
  2006年   152篇
  2005年   139篇
  2004年   132篇
  2003年   137篇
  2002年   150篇
  2001年   31篇
  2000年   18篇
  1999年   25篇
  1998年   43篇
  1997年   36篇
  1996年   29篇
  1995年   26篇
  1994年   27篇
  1993年   23篇
  1992年   17篇
  1991年   11篇
  1990年   13篇
  1989年   10篇
  1988年   10篇
  1987年   4篇
  1985年   6篇
  1984年   6篇
  1983年   2篇
  1982年   10篇
  1981年   7篇
  1980年   5篇
  1979年   4篇
  1978年   3篇
  1977年   3篇
  1974年   3篇
  1960年   1篇
  1937年   2篇
  1917年   1篇
排序方式: 共有2362条查询结果,搜索用时 15 毫秒
41.
Infiltrating macrophages accumulate in fatty streak lesions and transform into foam cells, leading to the formation of atherosclerotic plaques. Inflammatory mechanisms underlying the plaque formation mediated by NKG2D-positive lymphocytes such as CD8+ T cells, natural killer cells and natural killer T cells have been extensively investigated. Yet, the involvement of the NKG2D system itself remains poorly understood. Recent work in mouse models has shown that blockade of an NKG2D receptor–ligand interaction reduces plaque formation and suppresses inflammation in aortae. In this study, we conducted immunohistochemical analysis of NKG2D ligand expression in autopsy-derived aortic specimens. Foam cells expressing NKG2D ligands MICA/B were found in advanced atherosclerotic lesions accompanied by a large necrotic core or hemorrhage. Human monocyte-derived macrophages treated in vitro with acetylated low-density lipoproteins enhanced expression of MICA/B and scavenger receptor A, thus accounting for NKG2D ligand expression in foam cells infiltrating atherosclerotic plaques. Our results suggest that, as in mice, the NKG2D system might be involved in the development of atherosclerosis in humans.  相似文献   
42.
AIM:To study the relationship between adverse events(AEs),efficacy,and nursing intervention for sorafenibtherapy in patients with hepatocellular carcinoma(HCC).METHODS:We enrolled 37 consecutive patients withadvanced HCC who received sorafenib therapy.Relationships among baseline characteristics as well as AEoccurrence and tumor response,overall survival(OS),and treatment duration were analyzed.The nursingintervention program consisted of education regardingself-monitoring and AEs management,and telephoneRESULTS:A total of 37 patients were enrolled in the study,comprising 30 males(81%) with a median age of 71 years.The disease control rate at 3 mo was 41%,and the median OS and treatment duration were 259 and 108 d,respectively.Nursing intervention was given to 24 patients(65%).Every patient exhibited some kinds of AEs,but no patients experienced G4 AEs.Frequently observed AEs G2 included anorexia(57%),skin toxicity(57%),and fatigue(54%).Factors significantly associated with longer OS in multivariate analysis demonstrated that age ≤ 70 years,presence of G2 skin toxicity,and absence of G2 hypoalbuminemia.The disease control rate in patients with G2 skin toxicity was 13/20(65%),which was significantly higher compared with that in patients with no or G1 skin toxicity.Multivariate analysis revealed that nursing intervention and G2 skin toxicity were independent significant predictors for longer treatment duration.CONCLUSION:Skin toxicity was associated with favorable outcomes with sorafenib therapy for advanced HCC.Nursing intervention contributed to better adher-ence,which may improve the efficacy of sorafenib.  相似文献   
43.
BackgroundSubstance P (SP) and calcitonin gene-related peptide (CGRP) are released by the nociceptive sensory nerve and are involved in blood flow, pain and inflammation in the nasal mucosa. The purpose of this study was to assess the distribution of the SP and CGRP nerve fibres related to blood supply within human Schneiderian membrane of the maxillary sinus (MS).Material and methodsIn this study, the MS from Japanese cadavers was examined by whole-mount immunohistochemistry. Human male cadavers (ranging in age from 80 to 90 years) were used in this study.ResultsSP- and CGRP-positive fibres were found around large vessels of the medialis superior alveolar branches and also within the floor region of the MS. The floor region of the MS was composed of complex branches of these fibres.ConclusionOur results give useful information for surgical sinus floor elevation in this region of the MS. These anatomical features may assist in the execution of a successful surgical procedure.  相似文献   
44.
Primary graft failure (PGF) caused by ischemia‐reperfusion injury (IRI) is the strongest determinant of perioperative mortality after heart transplantation. Atrial natriuretic peptide (ANP) has been found to reduce the IRI of cardiomyocytes and may be beneficial in alleviating PGF after heart transplantation, although there is a lack of evidence to support this issue. The purpose of this study was to investigate the cardioprotective effects of ANP after prolonged hypothermic storage. For this purpose, an isolated working‐heart rat model was used. After the preparation, the hearts were arrested with and stored in an extracellular‐based cardioplegic solution at 3–4°C for 6 h and followed by 25 min of reperfusion. The hearts were divided into four groups (n = 7 in each group) according to the timing of ANP administration: Group 1 (in perfusate before storage), Group 2 (in cardioplegia), Group 3 (in reperfusate), and control (no administration of ANP). Left ventricular functional recovery and the incidence of ventricular fibrillation (VF) were compared. ANP administration at the time of reperfusion improved the percent recovery of left ventricular developed pressure (control, 45.5 ± 10.2; Group 1, 47.4 ± 8.8; Group 2, 45.3 ± 12 vs. Group 3, 76.3 ± 7; P < 0.05) and maximum first derivative of the left ventricular pressure (control, 47.9 ± 8.7; Group 1, 46.7 ± 8.8; Group 2, 49.6 ± 10.8 vs. Group 3, 76.6 ± 7.5; P < 0.05). The incidence of VF after reperfusion did not differ significantly among these four groups (71.4, 85.7, 57.1, and 85.7% in Groups 1, 2, 3, and control, respectively). This result suggests that the administration of ANP at the time of reperfusion may have the potential to decrease the incidence of PGF after heart transplantation.  相似文献   
45.
46.
47.
Background and Aim: Fulminant hepatitis is mainly caused by excessive immune response‐mediated liver injury and its definitive therapy is liver transplantation. Mesenchymal stem cells, one of the adult stem cells, have an immunomodulatory effect on immune cells and reside in various tissues. The aim of this study was to investigate a therapeutic effect of adipose tissue‐derived mesenchymal stem cells (ASCs) on fulminant hepatitis induced by concanavalin A (ConA). Methods: The ASCs were isolated from adipose tissues of BALB/c mice and confirmed by detection of cell surface markers and induction of multi‐lineage differentiation. BALB/c mice were injected with ConA and treated with ASCs, phosphate buffered saline (PBS) or splenocytes (SPLCs). Survival rates, levels of serum liver enzymes, titers of serum cytokines, histopathology and localization of ASCs were investigated. Result: The survival rate of ASC‐injected mice significantly increased compared to PBS or SPLC‐injected mice. This effect was dependent on doses and timing of ASCs injected. Improvement of liver enzyme levels, histopathological changes and suppression of inflammatory cytokine production were observed in ASC‐injected mice. Fluorescent stained ASCs were detected in inflammatory liver, but not in normal liver. Conclusion: These results suggest that ASC treatment has a high potential to be an innovative therapy for fulminant hepatitis.  相似文献   
48.
49.

Introduction

Bone cyst formation in hips increases as osteoarthritis worsens. Although bone cysts in hips have been described in many studies, their etiology remains unclear and under debate. The purpose of this study was to investigate the communication between a bone cyst and the joint space, as well as the relationship between the severity of osteoarthritis and the formation of subchondral bone cysts in dysplastic hips.

Method

We studied bone cysts from 150 dysplastic hips in 97 patients by computed tomography (CT) and plain radiography. We investigated the distribution of the bone cysts and the presence or absence of a communication path between the cysts and the joint space by three-dimensional (3D) CT.

Result

Of the 150 hips, 94 acetabula and 55 femoral heads were found to contain cysts. Of the 94 hips containing acetabular cysts, 89 and 5 hips showed black lines and gray lines connecting the cyst and the joint space, respectively, on 3D-CT. The rate of cyst presentation in the hip increased as the joint space became narrower. The number of hips that possessed cysts in the anterior and/or middle portion was significantly higher than that in the posterior portions.

Conclusion

Bone cysts in dysplastic osteoarthritic hips were found to communicate with the joint space in all cases. This suggests that the formation and enlargement of the cysts in dysplastic hips may be greatly influenced by the joint fluid. Cyst formation was initially observed in the anterior acetabulum, gradually progressing to involve the entire joint, including the posterior acetabulum and the femoral head, with worsening of the osteoarthritis.  相似文献   
50.

Objective

The purpose of this study was to determine the incidence of steroid-associated osteonecrosis (ON) of the talus in systemic lupus erythematosus (SLE) patients using a prospective magnetic resonance imaging (MRI) study.

Methods

We prospectively evaluated 110 SLE patients (220 tali) who required corticosteroid therapy using MRI. The incidence of ON of the talus was compared with the incidence of ON of the femoral head. We also divided these patients into two groups: those with and without ON of the talus. We compared these groups for gender differences, ages at initial corticosteroid therapy, and highest daily corticosteroid dosages.

Results

The incidence of ON of the talus was significantly lower than the incidence of ON of the femoral head (7.3 versus 49.5 %; p?<?0.001). No significant differences for gender, age at initial corticosteroid therapy, or highest daily corticosteroid dosage were observed between patients with and without ON of the talus. The rate of ON of the bilateral femoral head was significantly higher in those with ON of the talus than in those without ON of the talus.

Conclusion

Our results revealed that the incidence of ON of the talus was significantly lower than the incidence of ON of the femoral head.  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