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   5358篇
  免费   184篇
  国内免费   38篇
耳鼻咽喉   167篇
儿科学   183篇
妇产科学   291篇
基础医学   317篇
口腔科学   329篇
临床医学   412篇
内科学   1263篇
皮肤病学   58篇
神经病学   373篇
特种医学   241篇
外科学   1147篇
综合类   67篇
预防医学   103篇
眼科学   222篇
药学   164篇
中国医学   3篇
肿瘤学   240篇
  2024年   2篇
  2023年   33篇
  2022年   54篇
  2021年   125篇
  2020年   79篇
  2019年   88篇
  2018年   107篇
  2017年   111篇
  2016年   180篇
  2015年   198篇
  2014年   237篇
  2013年   307篇
  2012年   411篇
  2011年   380篇
  2010年   236篇
  2009年   210篇
  2008年   381篇
  2007年   472篇
  2006年   426篇
  2005年   427篇
  2004年   384篇
  2003年   250篇
  2002年   281篇
  2001年   39篇
  2000年   11篇
  1999年   15篇
  1998年   16篇
  1997年   15篇
  1996年   15篇
  1995年   12篇
  1994年   10篇
  1993年   7篇
  1992年   7篇
  1991年   11篇
  1989年   5篇
  1988年   2篇
  1987年   7篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1983年   2篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
  1966年   2篇
  1963年   1篇
排序方式: 共有5580条查询结果,搜索用时 31 毫秒
81.
Abstract

Serial magnetic resonance (MR) imaging has not yet been validated in the therapy of experimental intracerebral hematomas in a rat model. It is possible to test the effect of local fibrinolysis and aspiration on the clot volume using serial magnetic resonance imaging and different MR-sequences. Experiments were carried out in 22 male Sprague-Dawley rats. Intracerepra I hematoma was produced by injection of fresh autologous blood into the caudate nucleus using a double injection technique. Thirty minutes later 70 rats were treated by injecting 12 µl of recombinant tissue plasminogen activator. MR-imaging was performed immediately after generation of the hematoma and after clot lysis. The clot volume measured in the magnetic resonance images was compared with that obtained in stained histological serial sections at the end of the experiment. Serial MR scanning demonstrated a significant reduction (p<0.07) of hematoma volume after fibrinolysis followed by aspiration of the blood clot. The best correlation between MR- and histological volumetry was found on RF-spoiled FLASH 2D-images. This study documents the efficacy of MRI in detecting and delineating the size of acute intracerebral hematomas and its time course. Local fibrinolysis and aspiration can be simulated in an experimental rat model. [Neural Res 1998; 20: 349-352]  相似文献   
82.
The aim of this investigation was to compare the traditional method of manual cephalometric tracing with four different computerized tracing programs, where the lateral cephalograms were scanned at 300 dpi and digitized onscreen. Thirty randomly selected cephalometric radiographs were used in this study. Four programs Dolphin Imaging, Vistadent, Nemoceph, and Quick Ceph were evaluated. Three dental, 11 skeletal, and 1 soft tissue parameters were measured that consisted of 5 linear and 10 angular measurements. Statistical analysis was carried out using multivariate analysis of variance and Box's and Levene's tests. No statistically significant difference was found between manual tracing and the computerized tracing programs. The measurements obtained with the cephalometric analysis programs used in the study were reliable.  相似文献   
83.
Laser biostimulation in medicine has become widespread supporting the idea of therapeutic effects of photobiomodulation in biological tissues. The aim of this study was to investigate the biostimulation effect of laser irradiation on healing of cutaneous skin wounds, in vivo, by means of bioimpedance measurements and histological examinations. Cutaneous skin wounds on rats were subjected to 635 nm diode laser irradiations at two energy densities of 1 and 3 J/cm2 separately. Changes in the electrical properties of the wound sites were examined with multi-frequency electrical impedance measurements performed on the 3rd, 7th, 10th, and 14th days following the wounding. Tissue samples were both morphologically and histologically examined to determine the relationship between electrical properties and structure of tissues during healing. Laser irradiations of both energy densities stimulated the wound healing process. In particular, laser irradiation of lower energy density had more evidence especially for the first days of healing process. On the 7th day of healing, 3 J/cm2 laser-irradiated tissues had significantly smaller wound areas compared to non-irradiated wounds (p?<?0.05). The electrical impedance results supported the idea of laser biostimulation on healing of cutaneous skin wounds. Thus, bioimpedance measurements may be considered as a non-invasive supplementary method for following the healing process of laser-irradiated tissues.  相似文献   
84.
The objective of the present study was to determine whether preischemic administration of syringic acid (SA) would attenuate renal ischemia-reperfusion injury (IRI). Rats were divided into three groups: Sham group; IR group; and IR?+?SA group. The effects of SA were examined using biochemical parameters including serum ischemia-modified albumin (IMA), total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), tissue superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and malondialdehyde (MDA). The apoptosis status and histopathological changes were evaluated. After calculating the score for each histopathological change, the total score was obtained by summing all the scores. In the SA group, MDA, IMA, TOS, and OSI decreased significantly compared to the IR group. After SA administration, the increase in GPx activity was found to be significant. Apoptosis decreased significantly in the SA group compared with the IR group. The total score significantly decreased after administration of SA. Taken together, our findings suggest that SA preconditioning is effective in reducing tissue damage induced in kidney IRI. Renal histology also showed convincing evidence regarding the protective nature of SA.  相似文献   
85.
86.
Conclusion: IBCT technique should be preferred owing to its high graft survival rate and ABG gain. While no significant difference was found in middle ear pressures between ears that underwent IBCT and normal ears, compliance values were found to be decreased in patients undergoing IBCT. However, the lack of correlation between ABG gain and compliance values indicated that compliance increase had no effect on post-operative ABG results. Objective: The aim of the present study was to compare tympanometric and audiological parameters in patients undergoing inlay butterfly cartilage tympanoplasty (IBCT) with their normal ears and to determine their difference with normal ear tympanometric parameters. Methods: Overall, 25 patients that underwent an operation between August 2010–May 2014 were included in the present study. In 13 of these patients, the ear that did not undergo operation was normal. 0.5, 1, 2, 4?kHz pure sound average values, tympanometric measurements and compliance values of normal and operated ears were compared. Results: The graft survival rate in patients was found to be 92%. Mean pre-operative air–bone gap (ABG) was 16.4?±?5.4 in patients, while mean post-operative ABG was 10.9?±?5.8, with a statistically significant difference (p?=?0.001) While there was no significant difference between operated and normal ears of patients in terms of middle ear pressure (0.441), compliance values were significantly higher in normal ears than those in operated ears (0.032). When post-operative ABG gain was compared with compliance values, no significant correlation was found between ABG gain and compliance measurements (r?=??0.025 and p?=?0.936).  相似文献   
87.
88.
89.
90.
The main principle of reconstructive surgery is replacement of the defective tissues with like tissues. A full-thickness defect of the nasal ala should be reconstructed in three layers: innermost mucosal layer, outermost skin, and the cartilage in-between. The aim of this study is to describe a technique for single-stage, three-layer reconstruction of the full-thickness ala nasi defects. This technique was used on three patients with tumors involving the nasal ala. Resulting full-thickness defects are reconstructed with a mucocartilaginous turnover flap planned from the contralateral side. Aesthetically acceptable results are obtained without the compromise of the nasal airway and with minimal donor site morbidity. None of the patients requested a revision operation. In conclusion, this is a novel technique with minimal donor site morbidity and good postoperative results. Moreover, lost tissues are replaced with exactly the same kind of tissues.  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