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   2752篇
  免费   128篇
  国内免费   19篇
耳鼻咽喉   41篇
儿科学   215篇
妇产科学   149篇
基础医学   211篇
口腔科学   91篇
临床医学   251篇
内科学   563篇
皮肤病学   104篇
神经病学   145篇
特种医学   135篇
外科学   523篇
综合类   42篇
预防医学   56篇
眼科学   106篇
药学   137篇
中国医学   4篇
肿瘤学   126篇
  2024年   1篇
  2023年   25篇
  2022年   42篇
  2021年   85篇
  2020年   41篇
  2019年   49篇
  2018年   72篇
  2017年   63篇
  2016年   95篇
  2015年   97篇
  2014年   114篇
  2013年   150篇
  2012年   183篇
  2011年   220篇
  2010年   111篇
  2009年   88篇
  2008年   198篇
  2007年   199篇
  2006年   209篇
  2005年   191篇
  2004年   198篇
  2003年   147篇
  2002年   103篇
  2001年   71篇
  2000年   40篇
  1999年   30篇
  1998年   17篇
  1997年   10篇
  1996年   8篇
  1995年   4篇
  1994年   5篇
  1993年   1篇
  1992年   6篇
  1991年   7篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1974年   1篇
  1971年   1篇
  1963年   1篇
  1960年   1篇
排序方式: 共有2899条查询结果,搜索用时 15 毫秒
51.
52.
Susac's syndrome is characterized by the clinical triad of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss. We here report a case of 46 year old woman with a sudden diminution in visual acuity at the left eye, headache and decreased hearing at the right ear with mild confusion considered as Susac's syndrome with complete triad. Although it's a relatively rare entity, it should be kept in mind in differential diagnosis of the neurological disorders, especially in women in 20- to 40-year of age presenting with acute hearing loss.  相似文献   
53.
54.
55.
56.
57.
PURPOSE: To investigate the contribution of HCV infection to insulin resistance in chronic haemodialysis patients. MATERIALS AND METHODS: The study was performed with 55 patients who were on regular haemodialysis therapy three times per week. Of the 55 patients, 34 (20 females and 14 males with an average age of 40.9 years) were anti-HCV (+) and were defined as the HCV (+) group. The remaining 21 patients (8 females and 11 males with an average age of 50 years) were negative for HCV and other viral markers and were defined as the HCV (-) group. BMI of all patients were below 27. Insulin resistance (IR) was calculated according to the HOMA formula and patients were called HOMA-IR (+) if their HOMA scores were higher than 2.5. All of the HOMA-IR (+) patients in both groups were called the HOMA-IR (+) subgroup. None of the patients had a history of drug use or any diseases that were related to insulin resistance except uremia. In both groups and the healthy control group, insulin and glucose levels were studied at three different venous serum samples taken at 5- minute intervals after 12 hours of fasting. Other individual variables were studied at venous serum samples taken after 12 hours of fasting. RESULTS: HOMA scores were (3)2.5 in 22 of 34 HCV (+) patients (64.7%) and 7 of 21HCV (-) patients (33.33%) (p=0.024). Insulin levels of HCV (+) group (13.32 +/- 9.44mIU/mL) were significantly higher than HCV (-) (9.07 +/- 7.39mIU/mL) and the control groups (6.40 +/- 4.94mIU/ mL) (p=0.039 and p=0.021 respectively). HCV (+) patients were younger (40.94 +/- 17.06 and 52.62 +/- 20.64 years, respectively) and had longer dialysis duration (7.18 +/- 3.61 and 2.91 +/- 2.69 years, respectively). Significant positive correlations of HOMA score with insulin (r=0.934, p=0.000) and fasting glucose levels (r=0.379, p=0.043) were found in the HOMA- IR (+) subgroup. Also, a significant positive correlation was found between ALT and insulin levels in the HOMA IR (+) subgroup. C-peptide levels of both HCV (+) and (-) groups were significantly higher than the control group (p < 0.001). There were not any significant correlations between HOMA score and some of the other individual variables including levels of triglyceride, ferritin, ALT, iPTH and Mg in any of the groups. CONCLUSION: In chronic haemodialysis patients; HCV infection is related to a high prevalence of insulin resistance, higher insulin and glucose levels.  相似文献   
58.

Purpose

PDE5 inhibitors are widely used for the treatment of erectile dysfunction. However, these drugs have recently become popular among men without erectile dysfunction as a means of enhancing sexual performance and improving sexual desire. The aim of this study was to investigate the histopathological and ultrastructural effects of PDE5 inhibitors on the corpus cavernosum in young, healthy male rats.

Methods

Twenty-four 4-month-old male rats were divided into four groups: group 1 was the control group, group 2 rats received sildenafil citrate, group 3 rats received vardenafil hydrochloride, and group 4 rats received tadalafil. All drugs were administered for 4 weeks. Penile tissue was collected for electron microscopy and tissue collagen measurements. Electron microscopic analysis indicated that the number of active fibroblasts and macrophages and the synthesis of new collagen fibers increased in treated rats.

Results

Cavernous tissue collagen levels were significantly higher in the sildenafil-, vardenafil-, and tadalafil-treated groups than in controls (46.16 ± 4.9, 42.06 ± 2.4, 41.07 ± 2.4, and 29.20 ± 3.3, respectively) (p < 0.001).

Conclusions

Young men who use these drugs to enhance performance in the absence of erectile dysfunction may experience irreversible damage to the cavernosal tissue. However, more studies are needed to evaluate the molecular mechanisms by which PDE5 inhibitors affect the corpus cavernosum.  相似文献   
59.
The study was undertaken to search whether pedicle selection for ischemic preconditioning (IP) and duration of global ischemia applied after IP influenced efficacy of IP on flap viability in epigastric adipocutaneous island flap with bilateral pedicles in rat model. In total, 159 rats were divided into one control and three (primary, secondary, or bilateral pedicle) IP treatment groups. IP was performed on different pedicles by three cycles of 10 minutes of pedicle clamping and 10 minutes of release. After IP procedure secondary pedicle was ligated in all groups, and flaps were exposed to 0, 1, 2, 4, or 6 hours of global ischemia by clamping primary pedicle. In control groups, after the perfusion of bipedicled flaps for 1 hour, left pedicle was ligated and flaps were exposed to global ischemia as in IP groups. On day 5 post‐surgery, tissue samples and topographic measurements were taken. No significant differences in semi‐quantitative scorings of polymorphonuclear leukocytes infiltration, chronic inflammation, interstitial edema, neovascularization, VEGF, and CD105 expression levels among groups were found (P > 0.05). Percentages of necrosis were consistently smaller in IP groups compared to controls for the same duration of global ischemia, with exception of the no‐ischemia. Area of necrosis was significantly smaller in primary IP group versus secondary IP group in the absence of global ischemia (P < 0.01). In the presence of global ischemia, both primary and secondary pedicle IP groups had significantly smaller percentage of necrosis than controls (P < 0.05) and there was no significant difference between primary and secondary IP groups (P > 0.05). Thus, IP performed on different pedicles may ameliorate flap survival in a comparable fashion, depending on the duration of global ischemia. Secondary pedicle IP was as effective as primary pedicle IP and may be feasible in free flap transfers. © 2013 Wiley Periodicals, Inc. Microsurgery 34:129–135, 2014.  相似文献   
60.
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