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   566篇
  免费   27篇
  国内免费   19篇
耳鼻咽喉   8篇
儿科学   13篇
妇产科学   9篇
基础医学   86篇
口腔科学   10篇
临床医学   36篇
内科学   123篇
皮肤病学   21篇
神经病学   36篇
特种医学   80篇
外科学   58篇
综合类   27篇
预防医学   21篇
眼科学   5篇
药学   59篇
中国医学   1篇
肿瘤学   19篇
  2023年   2篇
  2021年   10篇
  2020年   4篇
  2019年   9篇
  2018年   15篇
  2017年   7篇
  2016年   5篇
  2015年   14篇
  2014年   24篇
  2013年   23篇
  2012年   24篇
  2011年   34篇
  2010年   24篇
  2009年   20篇
  2008年   13篇
  2007年   25篇
  2006年   29篇
  2005年   23篇
  2004年   16篇
  2003年   18篇
  2002年   13篇
  2001年   19篇
  2000年   20篇
  1999年   21篇
  1998年   21篇
  1997年   18篇
  1996年   13篇
  1995年   9篇
  1994年   12篇
  1993年   10篇
  1992年   9篇
  1991年   6篇
  1990年   4篇
  1989年   15篇
  1988年   7篇
  1987年   9篇
  1986年   10篇
  1985年   13篇
  1984年   8篇
  1983年   12篇
  1982年   6篇
  1981年   3篇
  1980年   2篇
  1979年   1篇
  1977年   4篇
  1975年   1篇
  1973年   1篇
  1970年   3篇
  1969年   3篇
排序方式: 共有612条查询结果,搜索用时 31 毫秒
1.
The management of patients with endoscopically removed malignant intestinal polyps is controversial. The risk of residual disease should be assessed against the risk of a surgical operation. The authors report 35 cases of malignant polyps (5.5% of 641 colonoscopically removed adenomas). Sixteen patients had carcinoma in situ and received no further treatment and 19 had invasive carcinoma (sessile in 6, pedunculated in 13). Of these 19, 7 did not undergo surgery--because of old age in 2, minimal invasion in 3, a low rectal location in 1 and refusal in 1. Twelve patients (3 with sessile, 9 with pedunculated polyps) underwent a surgical resection, and residual disease was present in 3 (25%), 1 with positive nodes. Reported criteria of increased risk of residual disease--cancer in lymphatics or veins, incomplete excision, tumour at resection margin, sessile and villous tumours--were present in nine. All three patients with residual disease had microscopically involved margins of resection. The authors believe that the increased risk of recurrence justifies the risk associated with subsequent surgical resection unless the patient is otherwise a poor operative risk.  相似文献   
2.
3.
Surgery in cirrhotic patients is associated with high morbidity and mortality related to portal hypertension and liver insufficiency. Therefore, preoperative portal decompression is a logical approach to facilitate abdominal surgery and hopefully to improve postoperative survival. The present study evaluated the clinical outcomes of 18 patients (mean age 58 years) with cirrhosis (seven alcoholics and 11 nonalcoholics) who underwent transjugular intrahepatic portosystemic shunt (TIPS) placement before antrectomy (n=5), colectomy (n=10), small-bowel resection (n=1), pancreatectomy (n=1) and nephrectomy (n=1). TIPS was performed a mean (+/-SD) of 72+/-21 days before surgery and induced a marked mean decrease in portohepatic gradient from 21.4+/-3.9 mmHg to 8.4+/-3.4 mmHg. Cirrhotic patients (n=17) who underwent elective abdominal surgery without preoperative TIPS placement were used as the control group. Both groups were matched for age, etiology of cirrhosis, indications for surgery, type of surgery and coagulation parameters. The mean Pugh score was significantly higher in the TIPS group (7.7 versus 6.2). No significant differences were observed for operative blood loss, postoperative complications, duration of hospitalization and one-month (83% versus 88%) or one-year (54% versus 63%) cumulative survival rate. Analysis using the Cox proportional hazards model showed that neither TIPS placement nor preoperative Pugh score were independent predictors for survival. The present study suggests that preoperative TIPS placement does not improve postoperative evolution after abdominal surgery in cirrhotic patients with good or moderately impaired liver function.  相似文献   
4.
Summary The immunoreactivity of polyclonal antiserum to neuron-specific enolase (NSE) has been investigated. Twenty-three cases of malignant lymphoma (ML) were studied and compared with previously published reports. In our study 11 out of 23 cases showed strong or weak NSE positivity; any type of ML could be positive or negative even among B or T cell ML. This study indicated that polyclonal NSE is not a specific marker; it might be an inconstant marker of ML with no apparent correlation between reactivity and morphology or phenotype.  相似文献   
5.
6.
Fifteen percutaneous renal biopsies from patients with acute renal failure due to acute interstitial nephritis (AIN), in almost all cases due to drugs, were studied by electron microscopy. Differential counting of interstitial cells showed an average of 69% lymphocytes (small and large) and 11 % macrophages. Plasma cells and eosinophils were comparatively rare. The infiltrate resembled that of acute rejection, suggesting a cellular hypersensitivity reaction. Proximal and distal tubules were severely affected focally. Migration of lymphocytes through the tubular basement membrane of otherwise well-preserved tubules was considered to be the first phase. Other tubules showed extreme thinning of the tubular basement membrane, with still intact cellular walls. Rupture of the tubular basement membrane and necrotic disintegration of tubular epithelial cells are probably late phenomena. The non-necrotic tubules displayed severe reduction of proximal brush border and proximal as well as distal tubular basolateral infoldings. Focal tubular disintegration leading to tubular block and/or backleak as well as decrease of proximal tubular sodium resorption leading to a decreased glomerular filtration (a mechanism probably also acting in ischemic acute renal failure) may all be factors responsible for the acute renal failure in AIN.  相似文献   
7.
Abstract: We report the first case of fatal anthrax meningoencephalitis in Hong Kong over the past 60 years. A 13 year-old boy presented with right lower quadrant pain, diarrhoea and progressive headache. Lumbar puncture yielded gram positive bacilli initially thought to be Bacillus cereus, a contaminant. He was treated with ampicillin and cefotaxime, but died 3 days after hospitalization. The organism isolated from blood and cerebrospinal fluid was later identified as Bacillus anthracis.  相似文献   
8.
ObjectiveTo screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS).MethodsStrains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tcr) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%).ResultsPCR analysis indicated that Tcr E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels.ConclusionsTetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment.  相似文献   
9.
10.
Cutis marmorata telangiectatica congenita (CMTC) is a rare congenital cutaneous vascular anomaly with a reticular marbled erythematous pattern, which can result in isolated benign skin lesions or less commonly be associated with systemic anomalies. Occasionally, the characteristic pattern of CMTC lesions is masked on initial presentation, creating a diagnostic conundrum that can result in unnecessary workups to rule out vasculopathy. We present the case of a female newborn with a red-blue ulcerated skin lesion on the right leg and foot, which initially appeared as retiform purpura but evolved to exhibit the mottled pattern of CMTC by 5 days of age. Clinicians must be made aware of this potential diagnostic trap in early CMTC to avoid invasive skin biopsies and unnecessary laboratory testing in neonates.  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