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   552篇
  免费   37篇
耳鼻咽喉   17篇
儿科学   11篇
妇产科学   15篇
基础医学   77篇
口腔科学   2篇
临床医学   28篇
内科学   152篇
皮肤病学   22篇
神经病学   25篇
特种医学   7篇
外科学   91篇
综合类   10篇
预防医学   47篇
眼科学   38篇
药学   25篇
中国医学   2篇
肿瘤学   20篇
  2023年   5篇
  2022年   7篇
  2021年   15篇
  2020年   11篇
  2019年   13篇
  2018年   22篇
  2017年   14篇
  2016年   14篇
  2015年   9篇
  2014年   25篇
  2013年   33篇
  2012年   40篇
  2011年   63篇
  2010年   33篇
  2009年   24篇
  2008年   48篇
  2007年   28篇
  2006年   42篇
  2005年   30篇
  2004年   17篇
  2003年   26篇
  2002年   18篇
  2001年   6篇
  2000年   6篇
  1999年   5篇
  1998年   4篇
  1997年   3篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1969年   1篇
  1968年   1篇
排序方式: 共有589条查询结果,搜索用时 203 毫秒
1.
2.
A boy is described with clinical features including post-natal short stature, short limbs, speech delay, relatively large skull, prominent metopic ridge, wide palpebral fissures, proptosis, epicanthic folds, capillary hemangioma between the eyes and nose, flat nasal bridge, everted and small nares, small ears with a narrow external auditory canal and thick lobes, short neck, brachydactyly, bilateral Simian creases, a single flexion crease of the first and fifth fingers, protruding abdomen, and bilateral cryptorchidism. Radiographs did not show any features of bone dysplasia. However, a delayed bone age was noted. The boy's parents are first cousins. To the best of our knowledge, this constellation of anomalies has not been reported before, and may be considered a new syndrome.  相似文献   
3.
A genomic clone expressing a Trypanosoma cruzi antigen in Escherichia coli was identified using human chagasic sera. Chagasic antibodies affinity purified on extracts of this clone recognized a high-molecular-weight protein expressed in all developmental stages of the parasite life cycle, as well as in various T. cruzi strains. The antigen is associated with the cytoskeleton of the parasite and localizes along the attachment region between the flagellum and the cell body. Antibodies to the recombinant antigen were detected in the sera of 115 chagasic patients from different endemic regions, but not in sera of patients with leishmaniasis, T. rangeli infection, or other parasitic diseases. Our data suggest that the presence of antibodies to this antigen may be specifically associated with Chagas' disease.  相似文献   
4.
AIM OF THE STUDY: To describe a technique of percutaneous CT guided catheter drainage of infected pancreatic necrosis and to report the results of this technique compared with those of the conventional surgical treatment and of other percutaneous drainage series. PATIENTS AND METHODS: Between 1992 and 1997, the series included 32 patients who had a severe acute necrotizing pancreatitis with a mean Ranson score of 4.6, scored into grade D (n = 10), and grade E (n = 22), according to the Balthazar radiological staging. Modified Van Sonnenberg 24 F double lumen catheters were used for continuous irrigation and aspiration. RESULTS: Forty-nine drains were inserted for 41 infected necroses and eight abscesses. Among the 32 patients, the proof of infected necrosis was obtained in 26 patients by fine needle aspiration and culture (enterococcus, staphylococcus, pseudomonas). The average delay of catheter insertion was 23 days after onset of pancreatitis; the mean duration of drainage was 43 days, and an average of three catheters per patient was required. Five patients (15%) died, and among the survivors, 16 (59%) presented 21 complications including 14 enterocutaneous or pancreatic fistulas. A subsequent surgical procedure including two necrosectomies was necessary in six patients. CONCLUSION: This study demonstrates that percutaneous drainage of infected pancreatic necrosis with a 15% mortality and 70% success rate, represents an interesting alternative to conventional surgery.  相似文献   
5.
6.
Background: Mesenchymal stem cells (MSCs) were isolated from various sources, including various types of tumors. However choosing an appropriate isolation method is an important step in obtaining cells with optimal quality and yield in companion with economical considerations. The purpose of this study was to isolate more pure MSCs from human breast tumor tissue by a modified explant culture method.

Methods and Materials: The tumor tissues (n = 8) were cut into 1 to 3-mm cube-like pieces (explant). Each explant was placed in a well of 24-well format plates, cultured in Dulbecco’s Modified Eagle’s medium (DMEM), and maintained at 37°C with 5% humidified incubator. Morphological phenotypes of the cells were surveyed by an inverted microscope and wells with rather homogenous fibroblast-like morphology cell were considered as positive and selected for more expansion and characterization.

Results: A total of 185 wells, 63.7% of wells were positive that were chosen for expansion. Flowcytometry analysis demonstrated that isolated cells were positive for CD73, CD44, CD29, CD105, and CD90 but negative for CD11b, CD45, CD34, and HLA?DR. In addition, cells possessed the capability of multipotential differentiation into osteoblasts and adipocytes.  相似文献   
7.
Background and purpose — It is unclear whether metal particles and ions produced by mechanical wear and corrosion of hip prostheses with metal-on-metal (MoM) bearings have systemic adverse effects on health. We compared the risk of heart failure in patients with conventional MoM total hip arthroplasty (THA) and in those with metal-on-polyethylene (MoP) THA.

Patients and methods — We conducted a retrospective cohort study using data from the Australian Government Department of Veterans’ Affairs health claims database on patients who received conventional THA for osteoarthritis between 2004 and 2012. The MoM THAs were classified into groups: Articular Surface Replacement (ASR) XL Acetabular System, other large-head (LH) (> 32?mm) MoM, and small-head (SH) (≤ 32?mm) MoM. The primary outcome was hospitalization for heart failure after THA.

Results — 4,019 patients with no history of heart failure were included (56% women). Men with an ASR XL THA had a higher rate of hospitalization for heart failure than men with MoP THA (hazard ratio (HR)?=?3.2, 95% CI: 1.6–6.5). No statistically significant difference in the rate of heart failure was found with the other LH MoM or SH MoM compared to MoP in men. There was no statistically significant difference in heart failure rate between exposure groups in women.

Interpretation — An association between ASR XL and hospitalization for heart failure was found in men. While causality between ASR XL and heart failure could not be established in this study, it highlights an urgent need for further studies to investigate the possibility of systemic effects associated with MoM THA.  相似文献   
8.
Hydrophilic polymer coatings were designed to reduce friction between the catheter and vessel wall and facilitate intravascular manipulations during catheterization and placement of drug‐eluting stents. One newly reported complication of such hydrophilic coatings is the fragmentation and embolization of the polymer, which can lead to ischemia and infarct by blocking the small vasculature. In this report, we present a patient with a non‐healing ulcer on the leg. Biopsy from the ulcer revealed the presence of hydrophilic polymer emboli within the dermal vessels. This is one of the few reports of such a complication involving the skin. Our objective is to emphasize the histopathologic features of this uncommon iatrogenic phenomenon.  相似文献   
9.
10.
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