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   2064篇
  免费   93篇
  国内免费   4篇
耳鼻咽喉   47篇
儿科学   159篇
妇产科学   71篇
基础医学   171篇
口腔科学   103篇
临床医学   175篇
内科学   439篇
皮肤病学   197篇
神经病学   132篇
特种医学   71篇
外科学   291篇
综合类   18篇
预防医学   51篇
眼科学   91篇
药学   66篇
中国医学   2篇
肿瘤学   77篇
  2024年   2篇
  2023年   12篇
  2022年   32篇
  2021年   54篇
  2020年   38篇
  2019年   48篇
  2018年   68篇
  2017年   47篇
  2016年   71篇
  2015年   77篇
  2014年   87篇
  2013年   126篇
  2012年   145篇
  2011年   158篇
  2010年   94篇
  2009年   72篇
  2008年   128篇
  2007年   166篇
  2006年   163篇
  2005年   126篇
  2004年   128篇
  2003年   93篇
  2002年   86篇
  2001年   21篇
  2000年   22篇
  1999年   19篇
  1998年   13篇
  1997年   12篇
  1996年   5篇
  1995年   1篇
  1994年   6篇
  1993年   5篇
  1992年   7篇
  1991年   8篇
  1990年   7篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   3篇
  1984年   1篇
  1981年   1篇
  1979年   1篇
  1974年   1篇
  1968年   1篇
排序方式: 共有2161条查询结果,搜索用时 13 毫秒
51.
Background and design: The aim of this study was to investigate the efficacy of 50% glycolic acid peeling performed at different phases of menstruation on acne. Materials and methods: This study included 30 patients with mild-to-moderate acne. Those with regular menstrual cycles and no history or laboratory evidence of hormonal pathology, hirsutism were selected. Thirty patients were divided in three groups. The first group received peeling applications in the first 7 days of menstruation; the second group received the peel between 10 and 14 days; and the third group received the peel during the last 10 days of menstruation. Results: The 30 female patients included in study. All patients’ menstrual cycles were regular. All groups were homogenous in terms of initial acne severity scores. Acne severity scores decreased in all groups after 3 months of therapy; statistically significant differences were achieved only in the second group. Discussion: The results of our study suggest that chemical peeling administered during ovulation provides the most significant benefit for acne lesions. Ovulation is the period when estrogen reaches its highest level. Estrogen decreases sebum production through different mechanisms. The beneficial effects of estrogen on acne and healing in combination with those of chemical peeling may cause synergistic therapeutic effects with pronounced results.  相似文献   
52.
53.
The purpose of the current study was to compare the characteristics of lung cancer patients who had exposure to asbestos and asbestos-related radiological findings (ARRF) to the characteristics of patients who had no exposure. Of the 766 lung cancer patients evaluated, 607 had no exposure to asbestos and no ARRF, 88 had ARRF and a history of exposure, remaining 71 patients had no exposure to asbestos occupationally and no ARRF, but we could not obtain environmental exposure history from them. So we excluded these 71 patients' data. The study patients were compared with respect to age, gender, smoking history, duration and nature of symptoms, findings on physical examination, tumor histological types, chest X-ray (CXR) findings, tumor site and stage, and survival. Lung cancer patients with ARRF were more often males, former smokers, and older than patients with no history of exposure to asbestos. There were no differences between the groups of patients in terms of the duration of symptoms, the distribution of symptoms, the findings on physical examination, tumor histological type, and the CXR findings. There was no difference between the two groups of patients in the distribution among tumor stages and median survival. The anatomic site of origin of the tumor in the group with ARRF was peripheral and in the lower zone of the lung. We suggest that specific attention should be given to the peripheral and lower zones of the lungs on CRX during the evaluation of the patients with ARRF for lung cancer.  相似文献   
54.
55.
Abstract –  The aim of this study was to investigate the long-term effects of the use of human cadaveric solvent-dehydrated bone graft and duramater as a barrier membrane for the treatment of oroantral communication. Standard oroantral osseous defects were created in five minipigs. Subjects received cancellous bone graft in the form of block or microchips, duramater or a combination of bone and membrane. Uneventful healing was achieved in all of the subjects, clinically including the control site which did not receive any material. The operated bone segments were evaluated both by radiological and histological examinations after 6 months. Radiological evaluation was carried out using bone density analysis software and histological evaluation made by light microscopy. Radiological and histological results revealed that bone grafting of oroantral osseous defects improved the bone quality. However, application of duramater did not change this activity, both alone or combined with bone grafts. Within the limits of this experimental study, although solvent-dehydrated bone grafts were found superior and could be applied for the healing of osseous oroantral defects, resorbable membranes did not contribute to this process.  相似文献   
56.
57.
The aim of study was to investigate the fate and the morphology of the cells which constitute the spermatogenic line, and to determine the distribution of occludin in the testis in adult vasectomized Wistar rats. The rats were divided into two groups: control group (sham-operated) and vasectomized group. One, 3 and 6 months after sham and vasectomy operations, testis samples were examined. The weight of the testes was found to be reduced 3 and 6 months after vasectomy. There was vacuolization in the seminiferous tubules one month after vasectomy. The tubules showed severe atrophy 3 and 6 months after vasectomy. The occludin immunolabeling in the 3- and 6-month groups was weak and diffuse, and the density of the protein was found to be decreased. The increase in the number of apoptotic cells was accompanied by a time-dependent decrease in the number of haploid, diploid and tetraploid cells. This study demonstrated that vasectomy causes degeneration in the seminiferous tubules with alterations in occludin distribution with a decrease in the number of spermatogenic cells. Moreover, these alterations increase in a time-dependent manner.  相似文献   
58.
BACKGROUND AND PURPOSE: The evaluation of adenosine deaminase (ADA) activity in sera of patients with hepatitis should be considered a useful tool in the monitoring of their clinical status. In this study, we aimed to determine the relationship between viral load, transaminase levels, and serum ADA levels in hepatitis B virus (HBV)- and hepatitis C virus (HCV)-infected patients. METHODS: Seventy three patients with hepatitis B, 71 patients with hepatitis C and 40 healthy individuals were included. Patients with HBV and HCV infections were classified into 3 groups according to viral load. Serum ADA levels were investigated by colorimetric assays. RESULTS: Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and ADA levels of HBV- and HCV-infected patients were higher than those of the control group. These differences were statistically significant for the levels of all enzymes in HCV-infected patients (p<0.05), and all except AST (p>0.05) in HBV-infected patients. ADA levels of HBV-infected patients with high viral loads were higher than those in HBV-infected patients with intermediate and low viral loads, and the difference was detectably significant between patients with high and intermediate viral loads. Evaluation of HCV-infected patients according to viral load showed no statistically significant relationship between viral load and serum ADA, ALT, and AST levels (p>0.05). HBV- and HCV-infected patients with high ALT and AST levels showed statistically significantly higher levels of ADA than patients with normal ALT and AST levels (p<0.001). CONCLUSIONS: We suggest that serum ADA levels are associated more with the level of serum transaminases than viral load in HBV- and HCV-infected patients. In the treatment of patients with hepatitis, serum ADA levels should be considered a useful tool for the monitoring of liver condition.  相似文献   
59.
Recently, Eve et al. (2007) reported that the expression of TP53 (NM_000546) was increased by 2.1-fold in whole spinal cord and 2.7-fold in the ventral horn of amyotrophic lateral sclerosis (ALS) patients. Based on this particular observation, we decided to evaluate whether the TP53 Arg72Pro polymorphism (rs1042522) (C215G) was implicated in the etiopathology of sporadic amyotrophic lateral sclerosis (SALS). Therefore, we genotyped 394 Turkish SALS patients and 439 matched healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). We did not find any association between overall SALS patients with the TP53 Arg72Pro polymorphism and controls (χ2 = 2.674; p = 0.263). Consequently the TP53 Arg72Pro polymorphism was not associated with SALS.  相似文献   
60.
Circulating adhesion molecule levels in childhood asthma   总被引:1,自引:0,他引:1  
The present study aims at comparing the levels of circulating forms of E-selectin, ICAM-1 and VCAM-1 in 10 patients with acute asthma, 10 stable atopic asthmatics, 10 nonatopic stable asthmatics and 10 age-matched healthy children. sE-selectin levels of patients with acute asthma were found to be significantly higher than that of the other three groups. The insignificant rise in sICAM-1 levels was attributed to the usage of inhaler corticosteroids. Serum sE-selectin and sICAM-1 seem to be promising serological markers for monitoring disease activity in childhood asthma.  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