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   1240篇
  免费   83篇
  国内免费   16篇
耳鼻咽喉   6篇
儿科学   25篇
妇产科学   20篇
基础医学   180篇
口腔科学   24篇
临床医学   84篇
内科学   355篇
皮肤病学   12篇
神经病学   32篇
特种医学   22篇
外科学   273篇
综合类   6篇
预防医学   72篇
眼科学   7篇
药学   64篇
肿瘤学   157篇
  2023年   15篇
  2022年   27篇
  2021年   51篇
  2020年   24篇
  2019年   26篇
  2018年   40篇
  2017年   30篇
  2016年   33篇
  2015年   35篇
  2014年   34篇
  2013年   53篇
  2012年   88篇
  2011年   89篇
  2010年   48篇
  2009年   46篇
  2008年   90篇
  2007年   94篇
  2006年   77篇
  2005年   71篇
  2004年   57篇
  2003年   46篇
  2002年   66篇
  2001年   15篇
  2000年   19篇
  1999年   10篇
  1998年   8篇
  1997年   3篇
  1996年   14篇
  1995年   7篇
  1994年   4篇
  1993年   3篇
  1992年   6篇
  1991年   9篇
  1990年   7篇
  1989年   9篇
  1988年   12篇
  1987年   4篇
  1986年   8篇
  1985年   8篇
  1984年   7篇
  1983年   7篇
  1982年   4篇
  1981年   6篇
  1977年   2篇
  1976年   4篇
  1973年   3篇
  1972年   5篇
  1971年   2篇
  1929年   2篇
  1902年   2篇
排序方式: 共有1339条查询结果,搜索用时 15 毫秒
61.
The congenital cystic dilatation of the liver and bile ducts (CDB) is a very uncommon disease. It often appears in females and most frequently in paediatric patients. Its etiopathogenesis is not yet completely defined. Its evolution includes, together with several complications, the malignant transformation. The Authors present the outcomes of their experience based on a series of 5 patients observed from 1991 till today. Apart from the rarity of this disease, their series is so interesting because 4 out of 5 are adult patients and the fifth one is over 15. In addition, differentiating from the literature trend, the group included only male patients. Are also discussed the most important aspects referring to nosology, epidemiology, etiopathogenesis, clinical pattern and its evolution of CDB, looking over a wide review too. The Authors extensively examine the diagnostic problems; owing to that the patients were observed in the period 1991-1999 it is necessary to clarify that some imaging methods, i.e. CSTscan and the bile duct MNR, were not yet introduced. The surgical treatment has been investigated as well, developed during its historical evolution until nowadays and our solutions for the 5 cases have been presented and discussed. In their series the Authors haven't ever observed during hospitalisation a malignant transformation.  相似文献   
62.
BACKGROUND: Despite advances in diagnostic modalities, small bowel tumours are notoriously difficult to diagnose and are often advanced at the time of definitive treatment. These malignancies can cause insidious abdominal pain and weight loss, or create surgical emergencies including haemorrhage, obstruction or perforation. The aim of the present study was to describe the clinical presentation, diagnostic work-up, surgical therapy and short-term outcome of 34 patients with primary and secondary small bowel tumours submitted for surgical procedures in an emergency setting and to look for a correlation between clinical presentation and the type of tumours. METHODS: From 1995 to 2005, 34 consecutive surgical cases of small bowel tumours were treated at the Department of Emergency Surgery of St Orsola-Malpighi University Hospital, Bologna, Italy. Clinical and radiological charts of these patients were reviewed retrospectively from the department database. RESULTS: All patients presented as surgical emergencies: intestinal obstruction was the most common clinical presentation (15 cases), followed by perforation (11 cases) and gastrointestinal bleeding (eight cases). Lymphoma was the most frequent histologic type (nine patients), followed by stromal tumours (eight patients), carcinoids (seven patients), adenocarcinoma (seven patients) and metastasis (three patients). Of the nine patients with lymphoma, eight were perforated, all patients with stromal tumours had bleeding, and all carcinoids patients had bowel obstruction. There were two patients with melanoma metastasis, both had bowel intussusception. Resection of the neoplasm was carried out in 32 patients and two patients were deemed unresectable and received a palliative procedure. CONCLUSIONS: The present study shows that there is a correlation between small bowel tumours and clinical emergency presentation: gastrointestinal stromal tumours (GIST) mostly bleed; carcinoids make an obstruction; lymphomas cause a perforation; and melanoma metastasis causes intussusception.  相似文献   
63.
All haemodynamically stable patients with blunt abdominal trauma can be managed conservatively by non-operative management which is the treatment of choice in 80% of liver trauma. Non-operative management, when feasible, yields very good results in terms of survival, need for blood transfusions, morbidity and reduction of hospital stay. The Authors retrospectively analyse their recent experience with liver trauma. Of 53 patients with blunt liver trauma, 36 underwent surgical treatment whereas 17 haemodynamically stable patients received non-operative management. After CT scans, all patients on non-operative management underwent haemodynamic monitoring, US and blood examinations. A percentage of 47.1 % had a > or = grade III trauma. The mortality and morbidity rates were 0% and no blood transfusions were needed. The efficacy of non-operative management was 100% and none of the patients needed subsequent surgical treatment. Our clinical experience demonstrates that non-operative management is feasible and effective even for higher grade traumas, but always requires strict clinical, haemodynamic and US monitoring and careful patient selection. Current progress in the field and recent evidence reported in the literature indicate the likelihood of further developments and more widespread utilisation of non-operative management in liver trauma.  相似文献   
64.
65.
Congenitally corrected transposition of the great arteries (ccTGA) is a rare anomaly characterized by atrioventricular and ventriculo-arterial discordance and several other malformations that eventually lead to heart failure. We describe the case of a 53-year-old woman with ccTGA and aortic insufficiency who was a candidate for heart transplantation due to end-stage congestive heart failure. Her condition deteriorated before a suitable donor heart could be found; therefore, we placed a left ventricular assist device in the right (systemic) ventricle. Concomitantly, we removed the aortic (systemic) valve, closed the aortic annulus with a bovine pericardial patch, and repaired the mitral valve. The patient recovered uneventfully and was discharged from the hospital 2 months postoperatively. She underwent cardiac transplantation approximately 6 months later and continued to do well after 18 months.  相似文献   
66.
This report details relationships between earthquake exposures in 1980 and 1983 to 1984 and psychological distress reported in 1994. Participants are 555 Italian male factory workers from Naples, Italy. Those men who experienced damage from the 1980 quake reported higher levels of psychological distress (across several dimensions of the Symptom Checklist) than those without damage; additionally, 30% of these men reported symptoms of posttraumatic stress disorder (PTSD). While men evacuated as a result of the 1983 to 1984 Bradyseism earthquakes did not report higher distress levels (Symptom Checklist) than their nonevacuated colleagues, they did report more PTSD-like symptoms than those not evacuated. Financial loss from the Bradyseism quakes was associated with higher distress across all measures (seven Symptom Checklist dimensions and presence of PTSD symptoms). Additionally, social network disruptions following 1983 to 1984 evacuation were associated with greater distress (not all measures). These findings suggest that psychological distress from natural disasters may be very long lasting.  相似文献   
67.
Numerous studies on neuro-immuno-modulation indicate that the thymus is involved in many neurological diseases, including experimental allergic encephalomyelitis (EAE). Twenty Lewis rats were induced for EAE. At X, XII, XX and XXX days post-inoculation the animals were killed, and the thymus was recovered and harvested. Specimens of thymus were submitted to morphological light microscopy analysis (1% toluidine blue) and ultra-structural analysis (transmission electron microscopy). Significant morphometric data were collected by examining the images quantitatively and by statistically analysing the values. Our results show that the microenvironment of the thymus is severally involved in acute EAE. Thymocytes and reticular epithelial cells show many changes which are closely related to the pathogenesis of EAE. In particular we observed: (1) inside the cell an increase in intra-cytoplasmic vacuoles, and changes in the thickness of the nuclear membrane, mitochondria, rough endoplasmic reticulum, cellular inter-digitations and cellular electron-density; (2) outside the cell an increase in pericellular translucent halo, intercellular spaces, intercellular contacts and apoptotic and necrotic figures. The evidence of a thymic role in MS may suggest the intriguing therapeutic concept of thymectomy in the management of this neurological disease.  相似文献   
68.

Background/purpose

Anorectal malformations occur in 1 per 4,000 live births and represent a surgical challenge. Although critically important, the basic mechanisms of normal anorectal union are incompletely understood. Fgf10 signaling is known to serve a key role in mesenchymal/epithelial interactions in many organ systems including the gastrointestinal tract (GIT). The authors therefore hypothesized that Fgf10 signaling has a central role in normal anorectal development.

Methods

Fgf10 expression in wild-type (Wt) embryos was evaluated using whole-mount in situ hybridization. Wt and Fgf10−/− embryos were harvested from timed pregnant mothers at E12.5 through E17.5 and were analyzed for anorectal phenotype.

Results

Wt development of union between anorectal structures is completed between E12.5 and E13.5 with luminal communication between distal rectal epithelium and anus. Fgf10 is discreetly expressed at E12.5 in the distal rectum. Fgf10−/− mutants show failure of union of the rectum and anus at an early stage (E13.5) and near term (E17.5).

Conclusions

Fgf10 is expressed in the rectum at the time when anorectal continuity is established, indicating a role in normal anorectal development. Fgf10 invalidation (Fgf10−/− mutant) results in a genetically reproducible anorectal malformation phenotype. Fgf10 function is critical for normal anorectal development.  相似文献   
69.
OBJECTIVES: (1) To compare two stool antigen EIAs (HpSA, FemtoLab) and PCR of ureaseA and cagA in feces, with (13)C-urea breath test (UBT). (2) To ascertain whether a simplified UBT (breath collection time = 10 min) is as reliable as the standard assay (30 min). DESIGN AND METHODS: Helicobacter pylori status was recorded in Group 1 (n = 187) by UBT, H. pylori stool antigen, ureA and cagA PCR in feces. UBT with 10, 20 and 30 min sampling was performed in Group 2 patients (n = 283). RESULTS: The sensitivity and specificity of HpSA, FemtoLab, and ureA were 67% and 99%, 90% and 96%, 35% and 98%, respectively. cagA results were positive in 16/48 H. pylori-positive, and in 5/100 H. pylori-negative patients. The results of UBT with a 10- and 30-min sampling strictly overlapped. CONCLUSION: UBT with 10 min breath collection and FemtoLab stool antigen assay are the most reliable non-invasive tests to diagnose H. pylori infection.  相似文献   
70.
Biological markers of lead exposure were measured in 20 dogs from five different habitats chosen on the basis of the degree of anthropogenic influence. None of the dogs had clinical signs of lead poisoning. Compared to controls, blood lead concentrations were significantly higher in dogs from industrial areas, confirming the role of lead emissions in environmental pollution and the possible role of dogs as biomonitors of lead exposure in these areas. Whole blood lead concentrations were similar in dogs living in urban and rural areas, probably due to "indirect" lead sources and due to decreased urban lead contamination. As in humans, individual variability was detected. No significant correlation between clinico-pathological changes (hematology, clinical chemistry, Delta-aminolevulinic acid dehydratase activity and other intra-erythrocytic metabolic parameters) and lead concentration were observed. Our findings suggest dogs can be useful as sentinels of environmental lead exposure.  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