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   343篇
  免费   7篇
耳鼻咽喉   1篇
儿科学   1篇
妇产科学   4篇
基础医学   30篇
口腔科学   47篇
临床医学   22篇
内科学   65篇
皮肤病学   2篇
神经病学   6篇
特种医学   4篇
外科学   101篇
综合类   1篇
预防医学   24篇
眼科学   3篇
药学   16篇
中国医学   1篇
肿瘤学   22篇
  2023年   2篇
  2022年   5篇
  2021年   8篇
  2020年   5篇
  2019年   4篇
  2018年   7篇
  2017年   13篇
  2016年   3篇
  2015年   9篇
  2014年   10篇
  2013年   12篇
  2012年   19篇
  2011年   23篇
  2010年   16篇
  2009年   9篇
  2008年   24篇
  2007年   15篇
  2006年   25篇
  2005年   24篇
  2004年   16篇
  2003年   14篇
  2002年   13篇
  2001年   8篇
  2000年   9篇
  1999年   11篇
  1998年   3篇
  1997年   1篇
  1996年   2篇
  1995年   4篇
  1992年   1篇
  1990年   5篇
  1989年   1篇
  1988年   2篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   5篇
  1983年   2篇
  1982年   5篇
  1979年   6篇
  1976年   1篇
排序方式: 共有350条查询结果,搜索用时 0 毫秒
81.
Introduction: Hepatic capillariosis, caused by Capillaria hepatica (Calodium hepaticum) (Bancroft, 1893), Travassos, 1915 (Nematoda, Trichinelloidea, Capillariidae), is a common zoonosis in rodents but is rare in humans. Seventy-two cases in humans have been reported worldwide since the first case was described by MACARTHUR in 192417,27. This study aimed to determine the prevalence of Capillaria hepatica in humans and rodents in an urban area of Porto Velho, the capital of Rondônia, in Brazil. Methods: After conducting a census of the area, 490 residents were randomly selected, and, after signing a term of consent, provided blood samples that were screened for anti-Capillaria hepatica antibodies. Simultaneously, rats were captured to assess the prevalence of this parasite in rodents by histopathological examination in liver sections. Results: A prevalence of 1.8% was found among residents who had specific antibodies at a dilution of 1:150, indicating exposure to parasite eggs; 0.8% of the subjects also had positive titers at a dilution of 1:400, indicating true infection. The prevalence in rats was 2%. Conclusions: The prevalence of infection with this parasite among humans and rats was low. While the prevalence encountered among humans was within the limits reported in the literature, the prevalence among rodents was much lower.  相似文献   
82.
Leiomyosarcoma of the pancreas   总被引:1,自引:0,他引:1  
Summary A 45-yr-old female patient was admitted with signs and symptoms of acute pancreatitis. She had no history of gallstones, alcohol, or trauma. Her CT scan was consistent with a cystic lesion of the pancreas. Because of her presenting symptoms and signs, she was initially treated as an acute pancreatitis. Followup CT scan showed absolutely no change in the cyst. Surgical consultation was requested. A diagnosis of a neoplastic cyst was made, and the patient was taken to surgery where a distal pancreatectomy and splenectomy was performed. Pathology revealed a leiomyosarcoma of the pancreas. Only 15 other cases of leiomyosarcoma of the pancreas have been reported thus far in literature.  相似文献   
83.

Background  

Human cytomegalovirus (CMV) infection still causes significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Therefore, it is extremely important to diagnosis and monitor active CMV infection in HSCT patients, defining the CMV DNA levels of virus replication that warrant intervention with antiviral agents in order to accurately prevent CMV disease and further related complications.  相似文献   
84.
85.
Hurtuk MG  Devata S  Brown KM  Oshima K  Aranha GV  Pickleman J  Shoup M 《American journal of surgery》2007,193(3):319-24; discussion 324-5
BACKGROUND: Long-term survival for duodenal adenocarcinoma is inconsistent in the literature, and the biology of duodenal adenocarcinoma is poorly understood. METHODS: One institution's experience with duodenal adenocarcinoma from 1984 to 2005 is reviewed. Clinicopathologic data were analyzed, and overall survival was estimated using Kaplan-Meier curves with log-rank test. RESULTS: Of the 52 patients, 35 (67%) underwent potentially curative surgery; 31 survived the postoperative period and were included in the analysis. Of these, the median survival was 34 months (range 6 to 186 months) compared with 13 months (range 1 to 24 months) for those not undergoing curative surgery (P < or = .001). Clinicopathologic factors favoring long-term survival were tumor size >3.5 cm (P < or = .001) and T-stage < or =4 (P = .014). CONCLUSIONS: Clinicopathologic factors important to survival in duodenal cancer are T4 tumor status and tumor size. Interestingly, larger tumors were less likely to be invasive, and patients with these tumors had improved survival. The biology of this cancer is poorly understood; therefore, aggressive resection for all duodenal adenocarcinomas is recommended for all patients medically fit to undergo resection.  相似文献   
86.

Background

The influence of positron emission tomography (PET) scanning with flourodeoxyglucose (FDG) on decision making for the treatment of patients with esophagogastric junction (EGJ) carcinoma is unclear as is the utility of the maximum standardized uptake value (SUV) as a prognostic indicator.

Methods

This study was a retrospective review of EGJ carcinoma cases at a single institution during a 5-year period.

Results

FDG-PET altered treatment in 13 of 64 patients (20%). Of these, 21 patients had PET scans before and after undergoing neoadjuvant chemoradiation (CRT) as well as surgery. Patients who had a decrease in SUV >50% had a 12-month disease-free survival advantage over patients a decrease in SUV <50% (93% vs 43%, P = .025).

Conclusions

FDG-PET alters treatment in a significant number of patients with EGJ carcinoma. A >50% decrease in SUV after CRT is associated with an improved prognosis.  相似文献   
87.

Background

Nisin, a naturally occurring antimicrobial peptide (AMP), is currently the focus of clinical trials as an intravaginal microbicide. Therefore its mechanism of interaction with various cell membranes was studied.

Study Design

Flow cytometry was used for quantitative estimation of membrane damage by nisin which was further determined by scanning electron microscopy (SEM). Affinity of nisin for different unilamellar liposome vesicles was determined spectroflurometrically and confirmed using laser scanning confocal microscopy (LSCM).

Results

Propidium iodide (PI) staining by flow cytometry exhibited selective membrane permeabilizing effect of nisin on sperm and bacterial membranes which correlated with ultrastructural changes. In vitro interaction of nisin with liposome model vesicles revealed significant leakage of calcein from liposomes composed of phosphatidylcholine/phosphatidylglycerol (POPC/POPG) (e.g., bacteria) and phosphatidylcholine/phosphatidylserine (POPC/POPS) (e.g., spermatozoa) as compared to phosphatidylcholine/phosphatidylethanolamine (POPC/POPE) vesicles (e.g., red blood corpuscles). LSCM results were in complete agreement with cell membrane affinity studies.

Conclusion

This unique property of nisin can be exploited in the development of a safe and effective vaginal microbicide for the prevention of sexually transmitted infections/acquired immunodeficiency syndrome (STIs/AIDS) and unplanned pregnancies.  相似文献   
88.
The purpose of this study was to assess in vitro the efficacy of nickel-titanium K3 rotary files and hand files for removal of gutta-percha and sealer from obturated root canals using either chloroform or chlorhexidine as solvents. Sixty extracted single-rooted bovine teeth with straight, large canals were prepared, obtured and randomly assigned to 3 groups (n=20). The teeth were stored at 37 degrees C for 1 month and then the gutta-percha and sealer were removed using different techniques, as follows. Group I: size 3 Gates-Glidden drills plus size 30 hand K-files and Hedstr?m files and chloroform; Group II: K3 NiTi rotary files and chloroform; and Group III: K3 NiTi rotary files and 2% chlorhexidine gel. Radiographs were taken and scanned and the images were digitized. The total area of the canal and the area with remaining obturation material were measured in millimeters using a computed image analysis system (ImageLab). Data were analyzed statistically by one-way ANOVA and Tukey test at 5% significance level. The groups differed statistically (p<0.05) with respect to the average percentage of remaining gutta-percha and sealer, presenting the following sequence of effectiveness (from most to least effective): Group I (15.48%), Group II (28.42%) and Group III (35.96%). The findings of this study showed that, despite the technique used for removal of filling material, none of the retreated canals were completely free of gutta-percha and sealer remnants. The use of stainless steel hand files resulted in a lesser amount of filling debris than the use of nickel-titanium rotary instruments.  相似文献   
89.

Ethnopharmacological relevance

Guduchi (Tinospora cordifolia), a widely used plant in folk and Ayurvedic systems of medicine is well known for its immunomodulatory activity; however, the presence of an immunomodulatory protein (ImP) in guduchi has not been investigated.

Materials and methods

Guduchi ImP was purified from dry stem powder extract by anion-exchange chromatography on Q-Sepharose. Characterization of guduchi ImP was performed by SDS-PAGE, periodic acid-Schiff staining, HPLC, and immunochemical analyses. Immunostimulatory activity was assessed by lymphocyte proliferation and macrophage activation assays. Fresh guduchi stem/leaf, guduchi satwa and guduchi capsules were also analyzed for the presence of guduchi ImP.

Results

Guduchi ImP was purified to homogeneity from dry stem powder extract (∼150 mg protein per 100 g guduchi stem powder) as a single chain acidic protein (25 kDa) without glycans; it was noticeably absent in guduchi leaf. Guduchi satwa and guduchi capsule preparations also lacked this protein. Guduchi ImP showed ∼3-fold mitogenic activity compared to untreated murine splenocytes in the 1-10 μg/mL concentration range; 5-7-fold increase in mitogenic activity was seen in the case of murine thymocytes vs. control. The purified protein also induced nitric oxide production from macrophages present in isolated murine peritoneal exudates cells. Guduchi ImP displays enhanced phagocytosis of yeast cells by macrophages. Guduchi ImP does not possess hemagglutination activity (towards rabbit and human erythrocytes of all blood groups) indicating that the immunomodulatory protein is not a lectin.

Conclusions

The confirmation of an immunomodulatory protein in guduchi stem showing lymphoproliferative and macrophage-activating properties reinforces the rationale of the use of guduchi preparations in several Ayurvedic medicines for immunomodulation. To our knowledge, this is the first report of an immunomodulatory protein isolated from guduchi.  相似文献   
90.

Introduction  

Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery.  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