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   5741篇
  免费   303篇
  国内免费   65篇
耳鼻咽喉   54篇
儿科学   69篇
妇产科学   36篇
基础医学   581篇
口腔科学   63篇
临床医学   364篇
内科学   1729篇
皮肤病学   86篇
神经病学   402篇
特种医学   216篇
外科学   1041篇
综合类   12篇
预防医学   113篇
眼科学   94篇
药学   330篇
中国医学   19篇
肿瘤学   900篇
  2023年   40篇
  2022年   51篇
  2021年   144篇
  2020年   75篇
  2019年   128篇
  2018年   139篇
  2017年   136篇
  2016年   147篇
  2015年   159篇
  2014年   213篇
  2013年   202篇
  2012年   390篇
  2011年   409篇
  2010年   285篇
  2009年   200篇
  2008年   353篇
  2007年   338篇
  2006年   374篇
  2005年   371篇
  2004年   323篇
  2003年   338篇
  2002年   361篇
  2001年   67篇
  2000年   61篇
  1999年   60篇
  1998年   97篇
  1997年   68篇
  1996年   75篇
  1995年   82篇
  1994年   61篇
  1993年   47篇
  1992年   30篇
  1991年   20篇
  1990年   17篇
  1989年   19篇
  1988年   18篇
  1987年   8篇
  1986年   10篇
  1985年   8篇
  1984年   7篇
  1983年   11篇
  1982年   9篇
  1981年   14篇
  1980年   12篇
  1978年   8篇
  1958年   13篇
  1957年   18篇
  1956年   24篇
  1955年   17篇
  1954年   15篇
排序方式: 共有6109条查询结果,搜索用时 15 毫秒
1.

Background

Photosensitizers used for photodynamic therapy (PDT) to treat dermatologic disease are metabolized into mainly protoporphyrin IX (PpIX), which has five absorption wavelength peaks: 410?nm, 510?nm, 545?nm, 580?nm, and 630?nm. Although only red light around 635?nm and blue light around 400?nm are used as light sources for PDT, the efficiency of PDT might be improved by using multiple wavelengths, including those that correspond to the other absorption peaks of PpIX. Furthermore, because the target disease often occurs on the face, a flexible-type light-source unit that can be fitted to the lesion without unnecessarily exposing the mucous membranes, e.g., the eyes, nostrils, and mouth, is preferred.

Objective

We investigated the efficacy of a flexible light-emitting diode (LED) unit that emits multiple wavelengths to improve PDT effects.

Methods

HaCaT cells were incubated with 5-ALA and subsequently irradiated with either a single wavelength or sequentially with two wavelengths. Cell viability and reactive oxygen species were analyzed. Nude mice were implanted with COLO679 cells by subcutaneous injection into the flank. 5-ALA was subcutaneously injected into the tumor. The tumor was irradiated with 50?J/cm2 (day 0) and assessed daily until day 21.

Results

The synergistic PDT effects of dual-wavelength irradiation and reactive oxygen species production were highest with the 405-nm and 505-nm wavelength combination. This dual wavelength combination was also the most effective in vivo.

Conclusion

We could therefore conclude that dual-wavelength PDT is an efficient strategy for improving the therapeutic effects of PDT. Using a flexible LED unit is expected to achieve more uniform irradiation of uneven areas.  相似文献   
2.
3.
4.
5.
We report a case of a patient in whom endoscopic band ligation was achieved for postpolypectomy gastric bleeding. A 76‐year‐old man visited our hospital because of anemia. Endoscopy revealed a gastric polyp, approximately 12 mm in diameter, on the lesser curvature in the distal gastric body. The polyp was considered to be the source of chronic anemia and was therefore removed by using standard careful snare‐cautery polypectomy technique. Four days later, follow‐up endoscopy was performed to evaluate the postpolypectomy site, and an active bleeding postpolypectomy ulcer was identified. Initial attempts to achieve hemostasis with ethanol injection were unsuccessful. Immediate hemostasis was obtained with a subsequent endoscopic band ligation device. There has been no recurrent bleeding. Endoscopic band ligation might be a good treatment modality for the treatment of a postpolypectomy gastric bleeding lesion.  相似文献   
6.
We investigated the clinical background of patients at Shin-Kokura Hospital who showed a positive culture of pleural effusion during the period from January 1998 through December 2002. Microorganism cultures of the pleural effusions of 127 patients were performed in this 5-year period. Seventeen patients showed a positive microorganism culture from a pleural effusion, and 12 of these patients (70.6%) were 60 years old or more. Ten patients were diagnosed with thoracic empyema. Thirteen patients had an underlying disease such as malignancy (5 cases), diabetes mellitus (4 cases), etc. A purulent effusion and a high concentration of lactic dehydrogenase (LDH) in the pleural fluid were more frequently recognized in the positive-culture group. A total of 21 strains of microorganism were isolated from the 17 patients, including 10 strains of Gram-positive cocci, 6 strains of Gram-negative bacilli, 3 strains of anaerobes, 1 strain of mycobacterium (Mycobacterium tuberculosis), and 1 strain of fungus. Susceptibility to antimicrobial agents was generally good for most of the microorganisms isolated. Of the 17 patients, chest-tube drainage was performed in 13, and 6 needed a surgical operation. Twelve patients improved, but 5 died. In this study, thoracic empyema accounted for 58.8% of the 17 cases with a positive culture of pleural effusion. Of the 10 thoracic empyema patients, 5 patients needed surgical treatment in spite of adequate antimicrobial treatment and chest-tube drainage. Our data indicate that thoracic empyema is still difficult to treat, and thus adequate and rapid treatment is needed for any pleural infection.  相似文献   
7.
A 73-year-old male with a history of diabetes mellitus was admitted to our hospital for acute renal failure. An ultrasonogram revealed bilateral hydronephrosis, which worsened despite insertion of a bladder catheter. Nephrostomy catheters were positioned bilaterally, and Candida albicans was found in the urine culture. The patient was successfully treated with intermittent direct irrigation and i.v. antifungal agent therapy. Since 1977, approximately 50 cases of fungus balls or fungal bezoars in the urinary tract have been reported, but the majority of these cases have been characterized by unilateral ureteral or bladder involvement. Herein, we report a case of acute renal failure as a result of bilateral ureteral obstruction by Candida albicans fungus balls.  相似文献   
8.
9.
Objective: Paraplegia remains a serious complication of aortic operations. The production of free radicals during reperfusion after transient ischemia is believed to induce secondary spinal neuronal injury, resulting in paraplegia. The aim of the present study was to clarify the protective effect and method of administration of antioxidants on the neurological and histological outcome in the animal model for reperfusion injury after transient spinal cord ischemia. Methods: New Zealand white rabbits underwent surgical exposure of the abdominal aorta that was clamped for 15 minutes to achieve spinal cord ischemia. Group A animals received two 10 mg/kg doses of 3-methyl-l-phenyl-2-pyrazolin-5-one (MCI-186) at the time of release of the aortic clamp and 30 minutes later. In group B, MCI-186, 5 mg/kg, was given three times, at the time of aorta clamp release, 30 minutes and 12 hours later. In group C (control group), one dose of vehicle was administered. Neurological status was assessed using modified Tarlov’s score until 168 hours after operation. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage. Results: Groups A and B animals had better neurological function than group C (p(0.001). In contrast, group C animals exhibited paraplegia or paraparesis with marked neuronal necrosis. The number of surviving neurons within examined sections of the spinal cord was significantly greater in group B than in group C (p(0.001). Conclusion: In a 15-minute ischemia-reperfusion model using rabbits, systemic repetitious administration of MCI-186, a free radical scavenger, was found to have a protective effect on the spinal cord neurons both neurologically and histologically. We postulate that the drug minimizes the delayed neuronal cell death for reperfusion injury after transient ischemia by reducing the free radical molecules. Moreover, it was thought that we could protect delayed neuronal cell death more effectively by administering MCI-18612 hours later.  相似文献   
10.
The 1st Japanese Urological Association-Japanese Society of Medical Oncology Joint Conference, titled 'A step towards better collaboration between urologists and medical oncologists', was held to coincide with the 44th Meeting of the Japan Society of Clinical Oncology, Tokyo, in October 2006. The main theme of the conference addressed the need for a subspecialty of medical oncologist within urology to keep abreast of advances in medical oncology. Urologists should become more involved in the postoperative management of urologic cancer. Consensus on the optimal way to move forward in the treatment of urological cancer is needed. The conference featured eight lectures surveying the present status of uro-oncology in Europe, the USA, Korea, Singapore, and Japan; the relationship between surgical oncologists and medical oncologists; global trends and international clinical trials in uro-oncology; and the future of urologic oncology. These were followed by a general discussion titled 'Achieving better collaboration between the surgical oncologist and the medical oncologist.' This report presents a roundup of the 1st Japanese Urological Association-Japanese Society of Medical Oncology Joint Conference.  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