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   10116篇
  免费   372篇
  国内免费   54篇
耳鼻咽喉   149篇
儿科学   139篇
妇产科学   78篇
基础医学   1207篇
口腔科学   209篇
临床医学   574篇
内科学   2455篇
皮肤病学   162篇
神经病学   907篇
特种医学   485篇
外科学   1522篇
综合类   25篇
一般理论   1篇
预防医学   277篇
眼科学   400篇
药学   716篇
中国医学   12篇
肿瘤学   1224篇
  2023年   41篇
  2022年   72篇
  2021年   156篇
  2020年   70篇
  2019年   122篇
  2018年   177篇
  2017年   130篇
  2016年   204篇
  2015年   181篇
  2014年   257篇
  2013年   337篇
  2012年   511篇
  2011年   586篇
  2010年   326篇
  2009年   304篇
  2008年   612篇
  2007年   670篇
  2006年   708篇
  2005年   701篇
  2004年   694篇
  2003年   622篇
  2002年   680篇
  2001年   173篇
  2000年   143篇
  1999年   167篇
  1998年   156篇
  1997年   167篇
  1996年   140篇
  1995年   123篇
  1994年   112篇
  1993年   105篇
  1992年   104篇
  1991年   89篇
  1990年   94篇
  1989年   71篇
  1988年   63篇
  1987年   52篇
  1986年   61篇
  1985年   59篇
  1984年   58篇
  1983年   54篇
  1982年   46篇
  1981年   34篇
  1980年   35篇
  1979年   34篇
  1978年   25篇
  1977年   35篇
  1976年   21篇
  1974年   17篇
  1969年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A 66-year-old woman time of 10 days. One month after radicalmastectomy, there was local recurrence, followed by multiplepulmonary metastases, and the patient died of respiratory failure5 months after surgery. The gray-white-colored tumor measured13x12x;10 cm, and its border was well defined. The tumor wascomposed of diffusely growing round or polygonal cells withvesicular nuclei, prominent nucleoli, and ample cytoplasm containingeosinophilic inclusions. Lymph node involvement was widespread.Both vimentin and keratin were clearly demonstrated by immunohistochemicalstaining. Ultrastructural studies revealed that the MRT cellscontained cytoplasmic whorls of intermediate filaments.  相似文献   
42.
An evaluation of the residual activity of quick-drying agents (alcoholic solutions) used for hygienic hand disinfection is described. We looked for residual efficacy following hand disinfection with soap and water alone or followed by one of two alcoholic handrub lotions supplied from an automatic hand washing machine. The bacterial counts on the hands obtained before and within 2 successive hours after disinfection showed that alcoholic chlorhexidine was the most effective for 10 minutes after contamination of the hands. WELPAS® (alcoholic chlorbenzarconium) followed this in its immediate effect and was better than soap and water alone. There were no significant differences after 30‘ or 120‘ between the three disinfecting methods.  相似文献   
43.
A case of cystadenocarcinoma of the appendix with a large cystic lesion is reported. A 49-year-old man undergoing a routine ultrasonic scan was incidentally found to have an abdominal mass measuring some 30 cm in size. The clinical presentation was asymptomatic, and the patient underwent a laparotomy without ascertaining a diagnosis preoperatively. The lesion, which derived from the appendix, was removed and was found to be cystic and contained huge amounts of mucin. The histological findings revealed a well-differentiated cystadenocarcinoma of the appendix, and immunohistochemical staining of the epithelium and mucinous implants in the mass demonstrated a positive reaction for carcinogenic antigens, including carcinoembryonic antigen and carbohydrate antigen.  相似文献   
44.
Development of a new wound dressing with antimicrobial delivery capability   总被引:1,自引:0,他引:1  
A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved.  相似文献   
45.
We used the Gorog Thrombosis Test to analyze the factors influencing the occlusion time, which represents platelet activation and subsequent occlusive thrombus formation, in 132 healthy Japanese volunteers (116 men, 16 women; mean age, 45.0 +/- 12.0 years). The Gorog Thrombosis Test was designed to evaluate platelet aggregation and thrombolytic activity under a high shear stress condition (175 dynes/cm) in a native blood sample in vitro. The mean +/- SD occlusion time was 154.8 +/- 64.7 s (men, 153.4 +/- 64.2 s and women, 165.4 +/- 56.5 s). The occlusion time was inversely correlated with von Willebrand factor ristocetin cofactor activity (VWF:Rco) (r = -0.242, P = 0.0055) and von Willebrand factor antigen (r = -0.230, P = 0.0080). The mean occlusion time in the group with VWF:Rco of at least 170% (137 s) was significantly shorter than that in the group with VWF:Rco less than 170% (156 s, P < 0.05). Platelet counts, other coagulation markers and smoking showed no significant correlations with occlusion time. Red blood cells (r = -0.177, P = 0.0365), hemoglobin (r = -0.191, P = 0.0245) and hematocrit (r = -0.182, P = 0.0329) also showed inverse correlations with the occlusion time. This report is the first to clearly demonstrate the role of von Willebrand factor in the formation of occlusive thrombi in the Gorog Thrombosis Test.  相似文献   
46.
The effect of dietary fiber on the induction of cytochrome P450IA1 in rat colonic mucosa after a single intragastric injection of 3-methylcholanthrene (3MC, 20 mg/kg) was investigated by examining the drug-metabolizing enzyme activity, immunoblotting for cytochrome P450IA1 and immunohistochemistry. 7-Ethoxycoumarin-O-deethylase activities were approximately 20-fold higher in microsomes from both proximal and distal portions of the colonic mucosa of control diet-fed 3MC-treated rats compared with those of control diet-fed untreated rats. Strong immunofluorescence for cytochrome P450IA1 was localized in the cytoplasm of the colonic mucosa surface epithelium from the control diet-fed 3MC-treated rats. 7-Ethoxycoumarin-O-deethylase activity and cytochrome P450IA1 content determined by immunoblotting were significantly lower in wheat bran-fed 3MC-treated rats than in control diet-fed 3MC-treated rats. Immunohistochemical analysis showed much weaker immunofluorescence for cytochrome P450IA1 in the surface epithelium of the colonic mucosa of the wheat bran-fed 3MC-treated rats. These observations suggested that dietary fiber can affect the induction of cytochrome P450IA1 in colonic mucosa by dietary inducers or carcinogens.  相似文献   
47.
Papillary fibroelastoma (PFE) is a rare and benign cardiac tumor typically found on the valvular endocardium. In most cases, PFE is identified incidentally on echocardiography or during cardiac surgery. The patient was a 73-year-old man who had been treated for hepatocellular carcinoma for 5 years. On echocardiography, a 2.5-cm diameter mass was detected in the pulmonary trunk just above the pulmonary valve. Through a transpulmonary arterial approach with cardiopulmonary bypass, the mass identified on the commissure of the right and posterior pulmonary cusp was surgically excised together with the attached endocardium. Despite the benign histology of PFE, lethal embolic events such as stroke, myocardial infarction, and pulmonary embolism are reported in some cases. To prevent such complications, tumor identification and surgical excision are essential.  相似文献   
48.
Aortic allograft valves were harvested from non-infected (bacterial or viral) cadavers within 24 hours of death with a family consent, and were sterilized by 4 degrees C antibiotic solution for 48 hours. Then, the allograft was preserved in the 4 degrees C nutrient medium (fresh; TC-199, calf serum and HEPES buffer) or in liquid nitrogen (-196 degrees C) after freezing to -80 degrees C by a programmed freezer. 10% dimethylsulfoxide (DMSO) was used for cryopreservation. Following germ-free confirmation, aortic allograft valves were implanted in 5 patients having aortic regurgitation with good results. Three fresh and two cryopreserved allograft valves were used. Although the follow-up term is very short (maximum 1 year) at the present time, the valve function is quite satisfactory, confirmed by cardiac catheterization and echocardiography. This is the first report in Japan with regard to cryopreservation of allograft valves and clinical use of fresh or cryopreserved valves. We believe that realization and progress of allograft preservation by cryo-technique and establishment of the tissue bank are important for the development of cardiovascular surgery in Japan.  相似文献   
49.
Surgical technique of experimental lung transplantation in rabbits.   总被引:1,自引:0,他引:1  
BACKGROUND: Although rabbits have often been used as an experimental model for the analysis of lung preservation, there are no reports of long-term survival after rabbit lung allotransplantation. The purpose of this study was to establish a lung allotransplantation model for the evaluation of acute lung rejection in the rabbit and to investigate the transplantation techniques in the rabbit. METHODS: Left unilateral lung allotransplantations were performed in 10 pairs of Japanese white male rabbits, weighing from 2.8 to 3.7 kg. Rabbits were divided into two groups. Group A rabbits (n=5) received Cyclosporine A (CsA) (20 mg/kg/day) orally for 5 days postoperatively, while Group B rabbits (n=5) received no CsA. All rabbits were sacrificed at the fifth postoperative day for histological examinations. RESULTS: Anastomoses of the pulmonary vein were achieved by using the atrial cuff technique. Satisfied blood flow was obtained in all arterial and venous anastomosis sites. Bronchial anastomosis was also well healed and all rabbits could maintain adequate spontaneous ventilation. In Group A, histopathology revealed that three cases were grade A0, one was grade A1 and the other was A2. In Group B, three cases lived for five days, and histopathology showed two cases were grade A2 and one case was grade A3. CONCLUSION: We established a left unilateral lung allotransplantation model in the rabbit and observed suppression of acute rejection of the transplanted lung by CsA. This study suggests that the rabbit is also an experimental model suited for the analysis of lung preservation as well as lung allotransplant rejection.  相似文献   
50.
PURPOSE: To evaluate the treatment results of low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy (ISBT) for T3 mobile tongue cancer. MATERIAL AND METHODS: Between 1974 and 1992, 61 patients with T3 mobile tongue cancer were treated with LDR ISBT using (192)Ir hairpins with or without single pins. In addition, between 1991 and 1999, 14 patients were treated with HDR ISBT. For nine patients treated with ISBT alone, the total dose was 59-94 Gy (median 72 Gy) within one week in LDR ISBT and 60 Gy/10 fractions/5 days in HDR ISBT. For 66 patients treated with a combination therapy of external beam radiotherapy (EBRT) and ISBT, the total dose was 12.5-60 Gy (median 30 Gy) of EBRT and 50-112 Gy (median 68 Gy) within 1 week in LDR ISBT or 32-60 Gy (median 48 Gy)/8-10 fractions/5-7 days in HDR ISBT. RESULTS: The 2- and 3-year local control rates of all patients were both 68%. The 2- and 3-year local control rates of patients treated with LDR ISBT were both 67%, and those with HDR ISBT were both 71%. The local control rate of patients treated with HDR ISBT was similar to those with LDR ISBT. CONCLUSIONS: ISBT for T3 mobile tongue cancer is effective and acceptable. The treatment result of HDR ISBT is almost similar to that of LDR ISBT for T3 mobile tongue cancer.  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