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   2613篇
  免费   152篇
  国内免费   19篇
耳鼻咽喉   44篇
儿科学   166篇
妇产科学   133篇
基础医学   288篇
口腔科学   138篇
临床医学   203篇
内科学   652篇
皮肤病学   80篇
神经病学   132篇
特种医学   83篇
外科学   328篇
综合类   31篇
一般理论   1篇
预防医学   106篇
眼科学   149篇
药学   146篇
中国医学   8篇
肿瘤学   96篇
  2024年   6篇
  2023年   41篇
  2022年   56篇
  2021年   106篇
  2020年   77篇
  2019年   97篇
  2018年   74篇
  2017年   87篇
  2016年   111篇
  2015年   122篇
  2014年   145篇
  2013年   178篇
  2012年   221篇
  2011年   205篇
  2010年   126篇
  2009年   115篇
  2008年   155篇
  2007年   143篇
  2006年   185篇
  2005年   157篇
  2004年   128篇
  2003年   99篇
  2002年   51篇
  2001年   13篇
  2000年   13篇
  1999年   6篇
  1998年   8篇
  1997年   6篇
  1996年   8篇
  1995年   9篇
  1994年   9篇
  1993年   3篇
  1992年   6篇
  1991年   1篇
  1990年   6篇
  1989年   4篇
  1988年   2篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
  1973年   2篇
排序方式: 共有2784条查询结果,搜索用时 0 毫秒
31.
INTRODUCTION: Translocation of bacteria from the gut into pancreatic necrosis is an important factor in the development of septic complications and mortality in acute pancreatitis. S-methylisothiourea (SMT) is an inducible nitric oxide synthase inhibitor that has been shown to decrease bacteria] translocation in sepsis and thermal injury. AIM: To investigate whether SMT could affect bacterial translocation in acute necrotizing pancreatitis. METHODOLOGY: Forty-five Sprague-Dawley rats were studied. Acute pancreatitis was induced in Group I and Group II by injection of taurocholate and trypsin into the common biliopancreatic duct. Group III underwent laparotomy with the manipulation (but not cannulation) of the pancreas and received saline injection. Group I rats received normal saline as a placebo, and Group II rats received SMT after surgery for 2 days. At 48 hours, blood was drawn for serum amylase determinations. Bacterial translocation to mesenteric lymph nodes and distant sites (pancreas, liver, and peritoneum) were examined. A point scoring system of histologic features was used to evaluate the severity of pancreatitis. RESULTS: Plasma amylase levels and pancreatic histologic score were significantly reduced in Group II rats given SMT compared with those in Group I rats given saline (p < 0.01, p < 0.05, respectively). All Group I rats had bacterial translocation to mesenteric lymph nodes compared with 7 of 12 rats in Group II (p < 0.05). There was no difference in bacterial translocation to distant organs between the two groups, although rates tended to be lower in Group II compared with Group I (p > 0.05). Bacterial counts in the pancreas were significantly reduced in Group II rats compared with those in Group I rats (p < 0.05). CONCLUSION: Treatment with SMT appears to have ameliorated the course of acute pancreatitis; however, mortality was not affected.  相似文献   
32.
33.
The mixture of olive oil and lime cream has been traditionally used to treat external burns in the region of Hatay/Antakya and middle Anatolia. Olive oil and lime cream have been employed by many physicians to treat many ailments in the past. A limited number of studies have shown the antibacterial effect of olive oil and that it does not have any toxic effect on the skin. But we did not find any reported studies on the mixture of olive oil and lime cream. The aim of this paper is to investigate the cytotoxic and antibacterial activity of olive oil and lime cream individually or/and in combination in vitro conditions, by using disk-diffusion method and in cell culture. The main purpose in using this mixture is usually to clear burns without a trace. Agar overlay, MTT (Cytotoxicity assay) and antibacterial susceptibility tests were used to investigate the cytotoxic and antibacterial activity of olive oil and lime cream. We found that lime cream has an antibacterial activity but also cytotoxic on the fibroblasts. On the other hand olive oil has limited or no antibacterial effect and it has little or no cytotoxic on the fibroblasts. When we combined lime cream and olive oil, olive oil reduced its cytotoxic impact. These results suggest that mixture of olive oil and lime cream is not cytotoxic and has antimicrobial activity.  相似文献   
34.
35.
Subject-specific four-layer boundary element method (BEM) electrical forward head models for four participants, generated from magnetic resonance (MR) head images using NFT (www.sccn.ucsd.edu/wiki/NFT), were used to simulate electroencephalographic (EEG) scalp potentials at 256 recorded electrode positions produced by single current dipoles of a 3-D grid in brain space. Locations of these dipoles were then estimated using gradient descent within five template head models fit to the electrode positions. These were: a spherical model, three-layer and four-layer BEM head models based on the Montreal Neurological Institute (MNI) template head image, and these BEM models warped to the recorded electrode positions. Smallest localization errors (4.1–6.2 mm, medians) were obtained using the electrode-position warped four-layer BEM models, with largest localization errors (~20 mm) for most basal brain locations. When we increased the brain-to-skull conductivity ratio assumed in the template model scalp projections from the simulated value (25:1) to a higher value (80:1) used in earlier studies, the estimated dipole locations moved outwards (12.4 mm, median). We also investigated the effects of errors in co-registering the electrode positions, of reducing electrode counts, and of adding a fifth, isotropic white matter layer to one individual head model. Results show that when individual subject MR head images are not available to construct subject-specific head models, accurate EEG source localization should employ a four- or five-layer BEM template head model incorporating an accurate skull conductivity estimate and warped to 64 or more accurately 3-D measured and co-registered electrode positions.  相似文献   
36.
Annals of Nuclear Medicine - This study investigates the prognostic value of 68Ga-Pentixafor PET/CT using PET-derived quantitative in multiple myeloma (MM) patients with suspected recurrence in...  相似文献   
37.
38.
The use of immediate on-site evaluation of fine-needle aspiration biopsy (FNAB) specimens can determine the adequacy of specimens and provides a specific preliminary diagnosis. In this prospective study, we evaluated the impact of on-site assessment of thyroid FNAB performed under ultrasound guidance. Totally, 204 (170 female, 34 male) patients (102 on site, 102 control group) were included. The patients were randomized on site and regular cytologic examination groups. Quick May-Grünwald Giemsa stain was used for on-site examination and FNA was continued until adequate aspirate for optimal cytological examination. Two (2.0 %) of the 102 patients evaluated with on-site examination had a nondiagnostic result. However, 16 (15.7 %) of the 102 patients examined by regular cytologic examination method, had nondiagnostic result. The difference between these two groups was statistically significant (p?<?0.0001). The major cause of a nondiagnostic thyroid FNAB specimen is the failure to aspirate a sufficient number of cells necessary for diagnosis cystic lesions. Immediate on-site evaluation can significantly decrease the nondiagnostic rate of thyroid FNAB specimens.  相似文献   
39.
40.
Purpose

The co-stimulatory molecules CD80 and CD86 are upregulated on activated antigen-presenting cells (APC). We investigated whether local APC activation, induced by subcutaneous (s.c.) inoculation of lipopolysaccharides (LPS), can be imaged by positron emission tomography (PET) with CD80/CD86-targeting 64Cu-labelled abatacept.

Procedures

Mice were inoculated s.c. with extracellular-matrix gel containing either LPS or vehicle (PBS). Immune cell populations were analysed by flow cytometry and marker expression by RT-qPCR. 64Cu-NODAGA-abatacept distribution was analysed using PET/CT and ex vivo biodistribution.

Results

The number of CD80+ and CD86+ immune cells at the LPS inoculation site significantly increased a few days after inoculation. CD68 and CD86 expression were higher at the LPS than the PBS inoculation site, and CD80 was only increased at the LPS inoculation site. CTLA-4 was highest 10 days after LPS inoculation, when CD80/CD86 decreased again. A few days after inoculation, 64Cu-NODAGA-abatacept distribution to the inoculation site was significantly higher for LPS than PBS (4.2-fold). Co-administration of unlabelled abatacept or human immunoglobulin reduced tracer uptake. The latter reduced the number of CD86+ immune cells at the LPS inoculation site.

Conclusions

CD80 and CD86 are upregulated in an LPS-induced local inflammation, indicating invasion of activated APCs. 64Cu-NODAGA-abatacept PET allowed following APC activation over time.

  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