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   1865篇
  免费   108篇
  国内免费   11篇
耳鼻咽喉   36篇
儿科学   149篇
妇产科学   60篇
基础医学   222篇
口腔科学   121篇
临床医学   147篇
内科学   402篇
皮肤病学   71篇
神经病学   101篇
特种医学   73篇
外科学   205篇
综合类   22篇
一般理论   1篇
预防医学   69篇
眼科学   98篇
药学   120篇
中国医学   7篇
肿瘤学   80篇
  2024年   6篇
  2023年   28篇
  2022年   45篇
  2021年   84篇
  2020年   66篇
  2019年   75篇
  2018年   59篇
  2017年   70篇
  2016年   94篇
  2015年   90篇
  2014年   108篇
  2013年   126篇
  2012年   157篇
  2011年   150篇
  2010年   93篇
  2009年   75篇
  2008年   94篇
  2007年   103篇
  2006年   122篇
  2005年   116篇
  2004年   92篇
  2003年   77篇
  2002年   33篇
  2001年   2篇
  2000年   1篇
  1999年   2篇
  1998年   7篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1985年   1篇
排序方式: 共有1984条查询结果,搜索用时 15 毫秒
101.
PURPOSE: To report the results of transscleral implantation of foldable intraocular lenses (IOLs). SETTING: Department of Ophthalmology Dokuz Eylül University School of Medicine, Izmir, Turkey. METHODS: Twenty eyes of 20 patients had transscleral fixation of a foldable IOL combined with conventional 3-port pars plana vitrectomy or anterior vitrectomy. Twelve eyes had lens luxation, 8 traumatic and 4 idiopathic. Six eyes were aphakic, 3 after extracapsular cataract extraction and 3 as a result of complicated phacoemulsification. One patient with a mature cataract and pseudoexfoliation had a wide zonular dialysis during phacoemulsification. One patient had an opacified hydrophilic acrylic IOL. RESULTS: The mean age of the patients was 52.9 years (range 17 to 80 years). The mean preoperative best corrected visual acuity (BCVA) was 20/63 (range counting fingers to 20/25). The mean preoperative refraction was +10.8 diopters (D) (range +10 to +13 D) and the mean preoperative astigmatism, 1.8 D (range 1.0 to 5.5 D). Sixteen IOLs were hydrophobic acrylic, 14 of which were 3-piece AcrySof MA60BM (Alcon) and 2 of which were Sensar AR40 (Allergan). Four IOLs, all VisaAcryl(Staar), were hydrophilic acrylic. The mean power of the IOLs was +22.0 D (range 19.0 to 26.0 D). The mean follow-up was 12 months (range 1 to 18 months). The postoperative BCVA ranged between 20/100 and 20/20, and the mean postoperative astigmatism was 1.1 D (range 0.5 to 4.0 D) at the last follow-up visit. The difference was statistically significant (P<.05). Suture exposure and cystoid macular edema were the only complications, each occurring in 2 eyes. CONCLUSION: Transscleral fixation of foldable IOLs takes less time and results in fewer complications and better visual outcomes.  相似文献   
102.
We defined patient demographics, type of the poisoning, distribution according to month, route and reason for exposure, mortality causes and rates from 682 poisonings admitted to University Hospital in Kayseri, Turkey to evaluate whether they follow the pattern of other countries. Poisoning were drugs (54.5%), inhalational poisonings including carbon monoxide (13.7%), food (12.4%), alcohol (7%), pesticides (5.4%) and corrosives (2.1%). In drug ingestions, psychoactive drugs most common; psychoactive, analgesic, and anti-inflammatory drugs were most frequent agents in multiple drug poisonings. Drugs were the most used poison while pesticides, mushrooms, methanol and carbon monoxide caused more deaths. The mortality rate was 2%.  相似文献   
103.
The goal of this retrospective study was to evaluate factors that increase the risk of bowel necrosis and document the outcome of bowel resection in patients with strangulated hernias. We identified 102 patients (60 men, 42 women) who underwent surgical treatment for an incarcerated hernia at the Kartal Education and Research Hospital Emergency Unit between April 1997 and April 2001. Patients in group 1 required intestinal resection (n = 16), and patients in group 2 did not (n = 86). The median age of the patients was 53 years (range 3–96). Demographic and surgical data were obtained from the patients charts and compared between the two groups. Women required bowel resections more often than men (p < 0.05). Patients older than 65 years and those with femoral or epigastric hernias required resection more often than patients younger than 65 years and those with inguinal, umbilical, or incisional hernias (p < 0.05 for all). Group 1 patients had a longer hospitalization and experienced more overall complications and wound infections than group 2 (p < 0.05 for all). In conclusion, incarcerated hernias are more common in men, but intestinal resection is required more often in women. The risk of intestinal resection is higher for patients with femoral hernias and those older than 65 years. Patients who undergo intestinal resection have a higher overall complication rate related to wound infections but not an increased risk of other complications or mortality.This study was presented at the 5th European Congress of Trauma and Emergency Surgery, Istanbul, Turkey, October 2002.  相似文献   
104.
O6-Methylguanine DNA methyltransferase (O6-MGMT) reverses DNA alkylation damage produced alkylating agents. O6-MGMT is also a major determinant of cellular resistance to adjuvant chemotherapy with alkylating drugs. O6-MGMT activity was measured in samples from patients with gastric cancer, including tumor, adjacent normal appearing mucosa, and peripheral blood leukocytes (PBL). O6-MGMT activity of PBL from healthy individuals was evaluated as control. There was no significant difference between controls and patients for O6-MGMT activity in PBL. O6-MGMT activity was significantly increased in tumor tissue. Tumor O6-MGMT activity was found to be independent from tumor subgroups and tumor grade. A positive correlation was determined between O6-MGMT activity in tumor and in circulating PBL. The results indicate that O6-MGMT, a defense protein against alkylating agent-mediated carcinogenesis, increased in gastric tumors. This may explain the low response rate to drug combinations, including chloroethylnitrosoureas, exhibited by patients with gastric cancer.  相似文献   
105.
A new ursane-type triterpenoid, 3 beta,11 alpha,21 alpha-trihydroxyurs-12-ene, named salvistamineol (1), has been isolated from the methanol extract of Salvia staminea. In addition to 1, the methanol extract yielded four known compounds and the acetone extract yielded twelve known compounds consisting of two sesquiterpenes, six diterpenoids, a triterpenoid, two steroids and one flavone. DNA damaging properties of the extracts and some isolated diterpenes were investigated against three yeasts and only taxodione gave a positive response and also showed the highest cytotoxic activity against a panel of cell lines among the investigated compounds in this study.  相似文献   
106.
BACKGROUND/AIMS: The causes of malnutrition in liver cirrhosis are multifactorial. Levels of IGF-1 (insulin like growth factor-1) that is a crucial regulator of intermediary metabolism decreases. The aim of this study was to analyze the effect of IGF-1 supplementation during liver cirrhosis induced by common bile duct ligation. METHODOLOGY: Rats were divided into five different groups: One sham and four experimental groups. Rats in three of four groups were treated with 2 micrograms/day IGF-1 with a different time of experiment in each group. Blood biochemical parameters, tissue malondialdehyde, glutathione levels and the activity of tissue antioxidant enzymes and conventional and immunohistochemical analysis of liver samples were studied for each group. RESULTS: Serum albumin, total protein, fibrinogen levels decreased and prothrombin time was prolonged in the bile duct ligated and transected experimental group but not in the IGF-I treated rats compared with the rats in sham group. Liver malondialdehyde levels significantly increased in control group but not in IGF-1 treated groups. The activities of antioxidant enzymes were decreased compared with the other groups. Histopathology findings of liver biopsy demonstrated intense degree fibrosis and overexpression of fibroblast growth factor and desmin in the control group but a lesser degree of those in the IGF-1 treated groups. CONCLUSIONS: IGF-1 treatment improves liver function and decreases oxidative liver damage and histopathological findings. Further studies are required to delineate the mechanisms of protective effects of IGF-1.  相似文献   
107.
Cranial metastasis because of lung cancer shows the poor prognosis. Cranial metastasis is common: In order lung, breast, skin, kidney, gastrointestinal system cancer is the 80% of the cause of metastasis. Cranial metastases are common in lung cancer especially in small cell lung cancer. Cranial metastasis can be seen in different location but leptomeningeal infiltration is rare and interesting. Because of this we will describe a case which has been death seven months after diagnose because leptomeningeal infiltration of small cell lung cancer.  相似文献   
108.
109.
Previous metabolic studies of selenium used pure selenium compounds with pharmacologic activities unrelated to selenium nutrition. Healthy men were fed foods naturally high or low in selenium while confined to a metabolic research unit. Selenium intake was 47 microg/d (595 nmol/d) for 21 d while energy intakes and body weights were stabilized and selenium excretion and intake came into metabolic balance. On d 22, selenium intake was changed to either 14 microg/d (177 nmol/d, low selenium) or 297 microg/d (3.8 micromol, high selenium) for the remaining 99 d. The absorption, distribution and excretion of selenium in food were similar to selenomethionine, and distinctly different from sodium selenite. Daily urinary selenium excretion and selenium concentrations in plasma and RBC showed the largest responses to selenium intake relative to interindividual variation. Urinary selenium and plasma selenium responded most rapidly to changes in selenium intake, whereas RBC reflected longer-term selenium intake. Given the difficulty of 24-h urine collections outside a metabolic research unit, RBC and plasma selenium seem to be the most useful indicators of selenium intake. During the intervention period, the high selenium group retained 15 mg (190 micromol) of selenium, with approximately 5 mg (63 micromol) going into skeletal muscle. The low selenium group lost only 0.9 mg (11 micromol) of whole-body selenium but lost 3.3 mg (42 micromol) from muscle, indicating that selenium was redistributed from muscle to tissues that have a higher metabolic priority for selenium such as testes. Fecal excretion decreased by half, representing an important but previously underappreciated adaptation to selenium restriction.  相似文献   
110.
Case 1. An 18-year-old white man with AML-M3 received allogeneic bone marrow transplantation (BMT) in August 1997. On the seventh day of BMT, he developed chills, fever (39.1 °C), anorexia, and perirectal pain. On physical examination, a hemorrhagic bulla and “punched out” ulceration were observed on the perirectal region. Subsequently, the ulcer was surrounded by a red, swollen, tender, cellulitic plaque ( Fig. 1 ).
Figure 1 Open in figure viewer PowerPoint The ulceration on the perianal region of the first patient  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