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   12608篇
  免费   558篇
  国内免费   67篇
耳鼻咽喉   129篇
儿科学   216篇
妇产科学   228篇
基础医学   1505篇
口腔科学   244篇
临床医学   777篇
内科学   2911篇
皮肤病学   330篇
神经病学   984篇
特种医学   561篇
外科学   2029篇
综合类   30篇
预防医学   288篇
眼科学   484篇
药学   929篇
中国医学   15篇
肿瘤学   1573篇
  2023年   40篇
  2022年   80篇
  2021年   177篇
  2020年   109篇
  2019年   156篇
  2018年   246篇
  2017年   204篇
  2016年   290篇
  2015年   250篇
  2014年   342篇
  2013年   425篇
  2012年   603篇
  2011年   703篇
  2010年   395篇
  2009年   352篇
  2008年   702篇
  2007年   784篇
  2006年   798篇
  2005年   795篇
  2004年   790篇
  2003年   719篇
  2002年   785篇
  2001年   259篇
  2000年   258篇
  1999年   263篇
  1998年   208篇
  1997年   184篇
  1996年   165篇
  1995年   132篇
  1994年   132篇
  1993年   132篇
  1992年   162篇
  1991年   143篇
  1990年   144篇
  1989年   162篇
  1988年   128篇
  1987年   112篇
  1986年   99篇
  1985年   96篇
  1984年   82篇
  1983年   68篇
  1982年   46篇
  1981年   45篇
  1980年   40篇
  1979年   45篇
  1978年   45篇
  1977年   52篇
  1976年   35篇
  1975年   28篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.

Background

There were few studies assessed the postoperative sarcopenia in patients with cancers. The objective of present study was to assess whether postoperative development of sarcopenia could predict a poor prognosis in patients with adenocarcinoma of esophagogastric junction, (AEG) and upper gastric cancer (UGC).

Methods

Patients with AEG and UGC who were judged as non-sarcopenic before surgery were reassessed the presence of postoperative development of sarcopenia 6 months after surgery. Patients were divided into the development group or non-development group, and clinicopathological factors and prognosis between these two groups were analyzed.

Results

The 5-year overall survival rates were significantly poorer in the development group than non-development group (68.0% vs. 92.6%, P?=?0.0118). Multivariate analyses showed that postoperative development of sarcopenia was an independent prognostic factor for poor overall survival (P?=?0.0237).

Conclusions

Postoperative development of sarcopenia was associated with a poor prognosis in patients with AEG and UGC.  相似文献   
2.
3.
Hidroacanthoma simplex (HAS) is a rare benign eccrine adnexal tumor. HAS is sometimes clinically or pathologically misdiagnosed as squamous cell carcinoma in situ (Bowen's disease; BD), seborrheic keratosis (SK) or other adnexal tumor. To date, there has never been a report focusing on dermoscopic features to distinguish HAS from BD and SK. We found the following dermoscopic findings to be characteristic of HAS: fine black dots/globules (75% of cases) and fine scales arranged annularly (100% of cases). In contrast, glomerular vessels, which are typically observed in BD, were not seen in any of the four cases. Cerebriform appearance and milia‐like cysts, which are typically observed in SK, were also not seen in any of the four cases. The existence of “scattered fine black dots/globules” and “fine scales arranged annularly”, and the absence of the glomerular vessels, may contribute to precise diagnosis of HAS. Even though HAS resembles BD or SK clinically, it can be distinguished from these by the characteristic dermoscopic features.  相似文献   
4.
We report a case of biliary cystadenocarcinoma which recurred 41 months postoperatively. A 60-year-old woman was admitted for further examination of multiple metastatic tumors and a large amount of ascites. Systemic administration of 5FU and CDDP caused her CEA level to decrease gradually and abdominal computed tomography revealed considerable reduction of the metastatic tumors and ascites. Since her general condition had improved, chemotherapy was continued in the outpatient clinic.  相似文献   
5.
6.
The Carpentier-Edwards pericardial bioprosthesis has been markedly improved in the long-term results and valve-related complications including valve dysfunction, compared to the previous generation bioprosthesis. We report a patient in whom transient prosthetic valve regurgitation and hemolysis occurred early after mitral valve replacement using a Carpentier-Edwards pericardial bioprosthesis and were resolved by preservative therapy. The patient was a 77-year-old female diagnosed with severe mitral valve stenosis and insufficiency. She underwent mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis. Opening and closing of the three leaflets looked good on intraoperative transesophageal echocardiography (TEE). The only prosthetic valve regurgitation was evident at the central region where the leaflets form coaptation, and no abnormal findings were seen. Serum lactate dehydrogenase (LDH) was decreased to 405 U/l after surgery. However, LDH again began to increase on the 3rd day after surgery and it increased to 1,830 U/l on the 14th day after surgery. Hemolytic urine was detected on 10th day after surgery. PVL was not detected, but moderate abnormal regurgitation from the outside of the stent pocket was detected on TEE. Revision of valve replacement was considered, but LDH thereafter to 393 U/l on 41st day after surgery. The TEE was repeated, and only a trace of central jet was detected without abnormal regurgitation, unlike the previous examination. The patient did not develop any complications thereafter and was discharged on 47th day after surgery. LDH was nearly normal at the time of discharge.  相似文献   
7.
Although aortic valve replacement (AVR) is an effective treatment for patients with aortic valvular disease, the implantation of a small aortic prosthesis may result in residual left ventricular outflow stenosis and transvalvular gradient. In this study, the outcome in the long-term period of patients treated with a small aortic prosthesis was analyzed retrospectively. Twenty-four patients with AVR were divided into two groups, group A and group B. Group A consisted of 16 patients with 21 mm-sized prosthetic valves, and group B consisted of 8 patients with 19 or 16 mm-sized prosthetic valves. There were no significant differences in preoperative cardiac function or operative procedure in the two groups. The mean follow-up period (months) was 55.0 in group A and 51.3 in group B. RESULTS: One patient died of cerebral infarction in group A. There were no significant differences in cardiothoracic ratio (CTR), left ventricular ejection fraction (LVEF), and left ventricular mass index (LVMI) between the two groups. Postoperative physical activity according to the New York Heart Association (NYHA) classification showed no significant differences in the two groups. Despite using a small prostheses for AVR, the postoperative course was good in the long-term period, although careful follow-up is necessary.  相似文献   
8.
Kenji Ohtsuka, MD and his colleagues at the Sapporo Medical University have investigated the central organization of the near response with anatomical and neurophysiologic studies in cats. Based on their data and clinical observations, they proposed that the rostral pole of the superior colliculus has a critical role in the control of accommodation, vergence, and fixation. Although the central pathways have yet to be fully worked out, the contributions of Dr. Ohtsuka, who died in 2005, have laid an important foundation in the understanding of these functions.  相似文献   
9.
Recently an essential role of interstitial cells of Cajal (ICC) within myenteric plexus (ICC-MY) was suggested in ascending contraction and descending relaxation in the mouse ileum. The role of ICC in these neural reflexes was examined in the distal colonic segments prepared from the wild type and c-kit mutant, W/W(V) mice, in the present study. Localized distension of the segments from the wild type mice by using a small balloon resulted in ascending contraction and descending relaxation. In the segments from the mutant mice, localized distension also induced these neural reflexes similar to those observed in the wild type mice. Immunohistochemical examination demonstrated that ICC-MY and ICC present in muscle layers (ICC-IM) were severely disrupted in the mutant mouse, but only ICC, present within submucosal plexus (ICC-SMP), remained unchanged. In the small strips with ICC-SMP absent prepared from the mutant mouse, electrical field stimulation induced contraction or relaxation in the absence or presence of atropine, respectively. It was suggested that ICC have no important role in the ascending and descending neural reflexes in the mouse distal colon, this is in direct contrast to the role of ICC-MY in the ileum.  相似文献   
10.
PURPOSE: The aim of this study is (1) to develop a new method of risk classification for clinically localized prostate cancer; (2) to examine it in terms of compatibility with existing data such as nomograms; and (3) to compare it with existing risk-grouping methods. MATERIAL AND METHODS: The new grading system introduced here consists of three factors. The first is a prostate-specific antigen (PSA) of 4.1-10.0 ng/ml (score 0), 10.1-20.0 ng/ml (score 1), and >20.0 ng/ml (score 2). The second is a Gleason score (GS) of 6 (score 0), 7 (score 1), and 8-10 (score 2). The third is T classifications (UICC 2002) of T1c-T2a (score 0), T2b-T2c (score 1), and T3a (score 2). The sum of the three scores was named Prostate Risk Index (PRIX). Then, the compatibility of PRIX with the Partin Table, Kattan Nomogram, and Roach's formula was examined. At the same time, PRIX was compared with D'Amico, the National Comprehensive Cancer Network (NCCN), and Seattle classifications. RESULTS: PRIX 0 corresponded to 1-2% of pathologic lymph node involvement (pLN+) according to the Partin Table; PRIX 1 to 3-4%; PRIX 2 to 7-10%; PRIX 3 to 14-18%; PRIX 4 to 24-29%; PRIX 5 to 32-37%; and PRIX 6 to 42%. PRIX well separated the risks with relatively narrow ranges of probability, while D'Amico, NCCN, and Seattle classifications generally gave wide ranges especially for high-risk groups, both in the Partin Table and Kattan Nomogram. Roach's formula sometimes overestimated the risk compared to the Partin Table. CONCLUSION: PRIX fully corresponded to the Partin Table in terms of pLN+, and corresponded to the other nomograms better than any existing risk-grouping method. PRIX may thus function as a prognostic factor or contribute to patient selection in clinically localized prostate 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