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   1385篇
  免费   102篇
耳鼻咽喉   4篇
儿科学   33篇
妇产科学   47篇
基础医学   190篇
口腔科学   27篇
临床医学   82篇
内科学   318篇
皮肤病学   72篇
神经病学   112篇
特种医学   27篇
外科学   293篇
综合类   10篇
预防医学   24篇
眼科学   39篇
药学   78篇
中国医学   5篇
肿瘤学   126篇
  2023年   16篇
  2022年   13篇
  2021年   13篇
  2020年   18篇
  2019年   24篇
  2018年   34篇
  2017年   24篇
  2016年   18篇
  2015年   34篇
  2014年   30篇
  2013年   37篇
  2012年   46篇
  2011年   60篇
  2010年   28篇
  2009年   34篇
  2008年   53篇
  2007年   61篇
  2006年   60篇
  2005年   61篇
  2004年   40篇
  2003年   59篇
  2002年   57篇
  2001年   59篇
  2000年   56篇
  1999年   74篇
  1998年   21篇
  1997年   9篇
  1996年   13篇
  1995年   15篇
  1994年   9篇
  1992年   41篇
  1991年   19篇
  1990年   22篇
  1989年   23篇
  1988年   17篇
  1987年   19篇
  1986年   41篇
  1985年   23篇
  1984年   17篇
  1983年   14篇
  1981年   12篇
  1979年   19篇
  1978年   9篇
  1976年   9篇
  1974年   12篇
  1971年   7篇
  1970年   22篇
  1969年   11篇
  1968年   9篇
  1966年   8篇
排序方式: 共有1487条查询结果,搜索用时 15 毫秒
101.
A variety of clinical variables and physiological parameters have been discussed in relation to postoperative survival and symptoms in aortic regurgitation (AR). Many of them have been derived from left ventricular morphology and functions, but there has been no parameter from aortic functions. As the heart is united with the aortic tree to form a circulatory system and both heart and aorta affect each other, aortic functions also have an important prognostic value after aortic valve replacement (AVR). This study was performed to clarify the participation of aortic functions in determining the prognosis after AVR. Fifteen consecutive patients undergoing isolated AVR for AR were evaluated. Twenty-one preoperative hemodynamic and dimensional variables of both heart and aorta were analyzed to determine the risk factors for early postoperative morbidity. These variables were obtained from chest X-ray film, electrocardiogram, echocardiogram, cine-aorto-ventriculogram and pressure manometries. All patients were divided in two groups according to the postoperative course. Group I composed of 10 patients took relatively smooth postoperative course, except two patients suffering from cardiac tamponade. Group II composed of 5 patients suffered from low cardiac output syndrome (LOS) and/or dangerous arrhythmias postoperatively. Two out of them died of uncontrollable ventricular arrhythmias. There were no statistic differences between two groups in the factors derived from preoperative examinations, i.e. CTR, LVDsI, PWT, R/Th, %FS, EDVI, EF, CI, LVEDP, etc. Mean aortic compliance of group II, (3.8 +/- 2.1) X 10(-4) mmHg-1, was, however, significantly lower than that of group I, (21.7 +/- 4.8) X 10(-4) mmHg-1, (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
102.
There are few published reports about the use of splenic needle biopsies in the investigation of focal splenic lesions. We report our experience with sonographically guided core-needle biopsies of splenic lesions in 4 patients. The biopsies resulted in the following diagnoses: sarcoidosis, malignant lymphoma, infarction, and scar tissue. Surgery was avoided in the 3 patients diagnosed with sarcoidosis, infarction, and scar tissue by ruling out the possibility of a malignant splenic tumor. None of the patients experienced significant complications. We conclude that splenic core-needle biopsy is a useful and safe diagnostic tool for the evaluation of focal splenic lesions.  相似文献   
103.

Background

It is known that complex regional pain syndrome (CRPS) occurs after arthroscopic rotator cuff repair (ARCR); however, few studies have investigated this complication. Therefore, the purpose of the present study was to evaluate CRPS after ARCR.

Methods

A total of 182 patients who underwent ARCR were enrolled in this study. The average age of patients was 62.8 ± 10.0 years, with an average follow-up period of 21.5 ± 38.1 months. CRPS criteria outlined by the Ministry of Health, Labor, and Welfare study team for CRPS in Japan (MHLWJ) and International Association for the Study of Pain (IASP 2005) were utilized for diagnosis. There are two rating systems for the “clinical purpose” and “research purpose” in both criteria, respectively. Clinical outcomes, including Japanese Orthopedic Association (JOA) and University of California, Los Angeles scores, were evaluated using univariate and multivariate analysis.

Results

CRPS exclusively occurred in the hand of the operated limb, developing within 3 months of surgery. Two or more of the following symptoms were noted in patients with the hand lesion associated with CRPS: edema (93.4%), restricted range of motion (83.4%), hyperalgesia (30.1%), paridrosis (20.4%), and atrophic change (12.2%). Under these conditions, the incidences of CRPS were 24.2% (44/182) when evaluated by the MHLWJ rating system for the “clinical purpose;” 11% (22/182) by the MHLWJ rating system for the “research purpose;” 6% (11/182) by the IASP 2005 for the “clinical purpose;” and 0.5% (1/182) by the IASP 2005 for the “research purpose.” Results of multivariate analysis demonstrated that “Function” in the JOA score was a risk factor for the development of CRPS after ARCR, when evaluated by a system for the “clinical purpose” of the MHLWJ.

Conclusion

Following ARCR, CRPS-induced hand lesions occur more frequently than is generally believed, thereby suggesting that its impact on surgical outcomes should be clarified in the future.  相似文献   
104.
105.
106.
BACKGROUND/AIMS: This study was performed to evaluate the efficacy and safety of percutaneous microwave coagulation therapy for superficial hepatocellular carcinoma located on the surface of the liver. METHODOLOGY: Among 58 cirrhosis patients with 71 hepatocellular carcinomas measuring < or = 20 mm in greatest dimension, 18 patients had a solitary superficial lesion located on the liver surface (superficial hepatocellular carcinoma group) and the other 40 patients had 53 lesions that were not in contact with the liver surface (non-superficial hepatocellular carcinoma group). All patients were treated by percutaneous microwave coagulation therapy alone and the response was assessed by using contrast-enhanced CT. The survival, tumor recurrence, and adverse effects were compared between the superficial and non-superficial hepatocellular carcinoma groups. RESULTS: The 4-year survival rates of the superficial hepatocellular carcinoma group (64.2%) and the non-superficial hepatocellular carcinoma group (58.9%) were not significantly different, and neither were the 4-year local recurrence rates (27.1% vs. 29.8%). Although there was a significantly higher incidence of severe pain during microwave irradiation in the superficial hepatocellular carcinoma group (23/47) when compared with the non-superficial hepatocellular carcinoma group (25/148), there were no differences between them in the incidence of fever or the changes in liver function after treatment. There were no serious adverse effects, such as hemorrhage or tumor cell seeding, in either group. CONCLUSIONS: Percutaneous microwave coagulation therapy can be performed safely, even in patients with superficial hepatocellular carcinoma and cirrhosis, so this method is effective for treating hepatic neoplasms regardless of the tumor location.  相似文献   
107.
We treated two patients with atrial fibrillation and stringlike left atrial appendage thrombus: a 66 year-old man who had apical hypertrophic cardiomyopathy and a 86 year-old woman with no underlying heart disease. In the patient with hypertrophic cardiomyopathy, transesophageal echocardiography showed a highly mobile stringlike echo protruding from the left atrial appendage and sometimes falling into the mitral orifice. Pathologic examination after excision proved the stringlike echo to be a pedunculated structure composed of red and white thrombi. Excision of thrombus was also planned for the woman, who had a history of recurrent cerebral embolism. Because her cerebral CT showed infarction with bleeding, however, surgery was postponed. The stringlike mobile thrombus was not detected by transesophageal echocardiography 1 month later, when a new embolic episode affected a foot. Clinical outcomes of these two patients differed remarkably. The critical findings by transesophageal echocardiography which facilitated differential diagnosis from cardiac tumors were: spontaneous contrast echo accompanying mural thrombuslike echo, and low flow velocity in the left atrial appendage. However, the differential diagnosis may be quite difficult in cases of tumors associated with atrial fibrillation.  相似文献   
108.
BACKGROUND: The toxicity of dietary nitrate (NO3-) is controversial. One reason is nitrate metabolism in the intestine is so complicated that it is far from fully understood. There is no study measuring breath nitric oxide (NO) and nitrous oxide (N2O) after ingesting vegetables and high-nitrate food at the same time. METHODS: Breath samples from 10 healthy young and 10 healthy old subjects were collected at 15-min intervals for 5 h after ingestion of 100 g of lettuce and during fasting (control). Breath NO and N2O were analyzed by a chemiluminescence and an IR-PAS analyzer respectively. RESULTS: N2O maximum concentration and excretions increased significantly after ingesting lettuce in each group [303 (30) vs. 750 (81) ppb, 771 (72) vs. 1668 (146) microg in young; 442 (52) vs. 1092 (109) ppb, 1088 (125) vs. 2100 (183) microg in old subjects; mean (SE), P<0.01], while NO did not. In addition, breath NO was strongly influenced by ambient NO, which varied greatly. N2O maximum level in old subjects after ingesting lettuce was higher than that of young subjects (750 vs. 1092 ppb, P<0.05), and significantly higher N2O concentration levels were seen at 30, 45, 60, and 105 min in old subjects. CONCLUSIONS: A large amount of N2O produced in the intestine and normal nitrate intake do not influence the breath NO concentration, probably due to its relatively small production. Higher maximum N2O concentration after ingesting lettuce in old subject is probably because more bacteria, which rapidly reduce dietary nitrate in the upper intestinal tract, inhabit the gut in old age. Our results suggested that breath N2O is a useful noninvasive maker to estimate dietary nitrate reduction in the intestinal tract.  相似文献   
109.
We have developed an iso-integral mapping technique that uses magneto-cardiogram (MCG) data to obtain a map as projected total current image on the torso from the heart. We have also investigated the applicability of iso-integral mapping to the diagnosis of ischemic heart disease. We simulated and measured the characteristics of two types of iso-integral maps: one using tangential (B xy ) components, and one using the normal component (B z ). Each vector component was measured by two types of superconducting quantum interference device (SQUID) system to determine the tangential and normal components. The tangential component of the magnetic field appeared to be equivalent to the current image in the myocardium projected on the observing plane, and we were able to obtain a projected total current image by integration of the tangential components during the depolarization and repolarization processes. And we found that the iso-integral maps of normal hearts showed similar pattern in both processes; however, those of ischemic hearts showed different patterns.  相似文献   
110.
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