首页 | 官方网站   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   13994篇
  免费   653篇
  国内免费   92篇
医药卫生   14739篇
  2023年   90篇
  2022年   162篇
  2021年   291篇
  2020年   180篇
  2019年   242篇
  2018年   258篇
  2017年   245篇
  2016年   281篇
  2015年   289篇
  2014年   370篇
  2013年   426篇
  2012年   666篇
  2011年   740篇
  2010年   450篇
  2009年   355篇
  2008年   649篇
  2007年   673篇
  2006年   717篇
  2005年   763篇
  2004年   703篇
  2003年   686篇
  2002年   767篇
  2001年   443篇
  2000年   442篇
  1999年   368篇
  1998年   201篇
  1997年   134篇
  1996年   123篇
  1995年   146篇
  1994年   115篇
  1993年   96篇
  1992年   269篇
  1991年   239篇
  1990年   231篇
  1989年   239篇
  1988年   210篇
  1987年   187篇
  1986年   163篇
  1985年   189篇
  1984年   102篇
  1983年   96篇
  1982年   45篇
  1981年   47篇
  1979年   89篇
  1978年   45篇
  1977年   59篇
  1975年   54篇
  1971年   47篇
  1969年   37篇
  1968年   38篇
排序方式: 共有10000条查询结果,搜索用时 16 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.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
3.
4.
A 69-year-old man was admitted to our kidney center with endstage renal failure. We started intermittent peritoneal dialysis immediately because of severe azotemia, hyperkalemia, and metabolic acidosis. Two weeks after admission, he developed uremic pericarditis with frequent ventricular premature contractions and supraventricular premature contractions. The intermittent peritoneal dialysis was then replaced by intensive hemodialysis, and oral administration of 300 mg/d of cibenzoline was started. Four days later, he developed thirst, weakness, and dyspnea due to respiratory muscular paralysis. We initiated respiratory support with a respirator because analysis of his blood gases revealed marked hypercapnia and hypoxia. He also developed hypoglycemia and prolonged PQ and QRS intervals on the electrocardiogram, which we believed were due to cibenzoline intoxication; we discontinued the cibenzoline immediately. All symptoms improved, and he was extubated 5 days later. After 2 months, his pericardial effusion disappeared. He now continues maintenance hemodialysis as an outpatient. We suspect that the cibenzoline induced the respiratory muscular paralysis for 2 reasons: 1) the patient experienced the respiratory muscular paralysis, at the same time he also experienced thirst, weakness, hypoglycemia, and prolonged PQ and QRS intervals on electrocardiogram, and all of these symptoms improved after the discontinuation of cibenzoline, and 2) his plasma concentration of cibenzoline became remarkably elevated, to 20 times above the standard therapeutic level. This patient's clinical course indicates that hemodialysis might be superior to intermittent peritoneal dialysis for treatment of cibenzoline intoxication.  相似文献   
5.
6.
7.
Definition of carcinoma of the gastric cardia   总被引:8,自引:0,他引:8  
Summary This study concerns the definition of carcinoma of the gastric cardia. The topography of the esophagogastric mucosal junction (mucosal EGJ) was investigated with an endoscope in 182 patients who were free of hiatal hernias, ulcers, and neoplasms in the esophagus and stomach. The relationship between the EGJ and the cardiac gland area was then examined histologically in 56 resected specimens containing intact EGJs and cardia gland areas. Furthermore the cancerous center was determined; the shortest distance between the cancerous center and the EGJ and the amount of esophageal invasion were measured in 102 resected carcinomas located close to the junction; the carcinomas contained the EGJ and were good enough for pathohistological examination. The EGJ was located 0.5–1.0 cm proximal to the His angle (the gastric cardia) in radiological and endoscopic examinations. Histologically the cardiac gland area was found to straddle the EGJ at a range of about 1 cm proximal and 2 cm distal to the junction. Among the upper stomach carcinomas, most of the tumors (87.5%) whose center was located within 2 cm from the EGJ invaded the esophagus. In conclusion, carcinoma of the gastric cardia is defined as a lesion with its center located within 1 cm proximal and 2 cm distal to the EGJ.
Definition des Kardiacarcinoms
Zusammenfassung Diese Untersuchung befaßt sich mit der Definition von Carcinomen der Kardia. An 182 Patienten, die weder Hiatushernien, Ulcera noch Neoplasien des Oesophagus bzw. des Magens aufwiesen, wurde die Lage des Übergangs von der Oesophagus- zur Magenmucosa (esophagogastric mucosal junction, EGJ) endoskopisch untersucht. Dann wurde die Beziehung zwischen EGJ und dem Drüsengebiet der Kardia histologisch anhand von 56 Resektaten mit intaktem EGJ und Kardiadrüsenzone untersucht. Außerdem wurde an 102 resezierten Carcinomen mit Sitz in der Nähe des gastrooesophagealen Übergangs die kürzeste Ent fernung zwischen Carcinomzentrum und EGJ und das Ausmaß der Oesophagusinfiltration bestimmt; die Proben schlossen den EGJ ein und konnten pathohistologisch beurteilt werden. Bei der radiologischen und endoskopischen Untersuchung fand sind der EGJ 0,5–1,0 cm vom His-Winkel entfernt. Die histologische Untersuchung zeigte, daß die Kardiadrüsenzone sich vom EGJ etwa 1 cm nach proximal und 2 cm nach distal erstreckt. Die meisten Tumoren des oberen Magens (87,5%), deren Zentrum innerhalb von 2 cm vom EGJ entfernt lag, infiltrierten in den Oesophagus. Ein Kardiacarcinom ist demzufolge als Läsion zu definieren, deren Zentrum innerhalb von 1 cm proximal und 2 cm distal des EGJ liegt.
  相似文献   
8.
The optimal size of tricuspid valve annular area (TVAA) by annuloplasty for tricuspid regurgitation remains controversial. Recently, we developed a new measuring system which permits to do real-time measurement of tricuspid valve annular area in anesthetized dogs. Using this system, we studied the optimal size of TVAA by annuloplasty. After the right atrial incision, a metal thread which functions as a sense loop of the electromagnetic fields was stitched along the tricuspid valve annulus (visible juncture of the valve leaflets and the cardiac wall). The drive coil assembly was placed perpendicular to the extension of the long axis of the heart and was directed toward the tricuspid valve region. During control conditions, the maximum TVAA appeared at the onset of ventricular systole. The minimum TVAA appeared during the early ventricular diastolic phase which included the ventricular isovolumic relaxation phase. The maximum TVAA varied in five dogs between 2.2 cm2 and 3.1 cm2, the minimum TVAA also varied between 1.8 cm2 and 2.5 cm2: During regular sinus rhythm, a decrease of TVAA during one cardiac cycle ranged between 11.9% and 22.4% of the maximum size. When TVAA was not decreased by annuloplasty to the minimum area which was observed during cardiac cycle in the control state, the cardiac output and the right atrial pressure remained unchanged, because the ventricular filling was not obstructed. On the other hand, when TVAA was decreased smaller than this minimum area, the cardiac output decreased and the right atrial pressure rose.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
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   
10.
OBJECTIVE: Standard chemotherapy shows relatively low long-term survival in patients with poor-risk testicular germ cell tumor (GCT). First-line high-dose chemotherapy (HD-CT) may improve the result. High-dose carboplatin, etoposide, ifosfamide chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) was investigated as first-line chemotherapy in patients with advanced testicular GCT. METHODS: Fifty-five previously untreated testicular GCT patients with Indiana 'advanced disease' criteria received three cycles of bleomycin, etoposide and cisplatin (BEP) followed by one cycle of HD-CT plus PBSCT, if elevated serum tumor markers were observed after three cycles of the BEP regimen. RESULTS: Thirty patients were treated with BEP alone, because the tumor marker(s) declined to normal range. Twenty-five patients received BEP and HD-CT. One patient died of rhabdomyolysis due to HD-CT. Three and six (13% and 25%) out of 24 patients treated with BEP and HD-CT achieved marker-negative and marker-positive partial responses, respectively. The other patients achieved no change. Fifteen (63%) are alive and 14 (58%) are free of disease at a median follow-up time of 54 months. Severe toxicity included treatment-related death (4%). CONCLUSIONS: HD-CT with peripheral stem cell support can be successfully applied in a multicenter setting. HD-CT demonstrated modest anticancer activity for Japanese patients with advanced testicular GCT and was well tolerated. This regimen might be examined for further investigation in randomized trials in first-line chemotherapy for patients with poor-risk testicular GCT.  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-23

京公网安备 11010802026262号