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   1192篇
  免费   89篇
  国内免费   20篇
耳鼻咽喉   50篇
儿科学   37篇
妇产科学   20篇
基础医学   136篇
口腔科学   34篇
临床医学   248篇
内科学   199篇
皮肤病学   12篇
神经病学   21篇
特种医学   172篇
外科学   93篇
综合类   33篇
预防医学   86篇
眼科学   6篇
药学   78篇
中国医学   4篇
肿瘤学   72篇
  2023年   9篇
  2021年   17篇
  2019年   11篇
  2018年   11篇
  2017年   18篇
  2016年   19篇
  2015年   10篇
  2014年   32篇
  2013年   44篇
  2012年   31篇
  2011年   43篇
  2010年   40篇
  2009年   54篇
  2008年   49篇
  2007年   29篇
  2006年   29篇
  2005年   27篇
  2004年   25篇
  2003年   25篇
  2002年   28篇
  2001年   24篇
  2000年   33篇
  1999年   24篇
  1998年   51篇
  1997年   44篇
  1996年   40篇
  1995年   41篇
  1994年   30篇
  1993年   28篇
  1992年   15篇
  1991年   18篇
  1990年   19篇
  1989年   42篇
  1988年   39篇
  1987年   28篇
  1986年   20篇
  1985年   32篇
  1984年   21篇
  1983年   16篇
  1982年   23篇
  1981年   16篇
  1980年   20篇
  1979年   15篇
  1978年   17篇
  1977年   17篇
  1976年   19篇
  1973年   6篇
  1972年   6篇
  1971年   8篇
  1969年   7篇
排序方式: 共有1301条查询结果,搜索用时 156 毫秒
1.
This is the third and final part of a series of articles that report the findings of a study that investigated the effects of a summer externship program on the transition into a professional role among nurses who participated in a summer nurse externship program at an acute care pediatric hospital. Specifically, this article reports the retention and recruitment benefits of a summer nurse externship program for the institution from 1998 through 2003. A total of 153 externs out of the 193 (79.0%) assumed a registered nurse position at the institution, and 77% remained in that role for 12 months. Overall, the nurse extern program for this institution appeared to be an effective recruitment and retention strategy that is on par with the institution and national data for retention and turnover data.  相似文献   
2.
3.
Coronary artery bypass grafts: visualization with MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; Drinkwater  DC  Jr; Corday  SR 《Radiology》1987,162(1):175
  相似文献   
4.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
5.
BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. METHODS: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis.  相似文献   
6.
An experimental model with a static positioning frame, pressure-sensitive film (Fuji), and a microcomputer-based video digitizing system, previously developed by the two senior authors, was used in this study to examine the effects of increasing perilunate instability on the load transfer characteristics of the wrist. These effects included a significant dorsal ulnar shift of the scaphoid centroid with increasing perilunate instability together with a less dramatic palmar ulnar shift of the lunate centroid. Overall, the scaphoid contact area was found to decrease as the stage of perilunate instability increased, even in ulnar deviation and/or extension, which in the normal wrist was found to be the positions that had the greatest scaphoid contact area. Average pressures in the high pressure zones were found to significantly increase in wrists with a stage III instability compared with normal wrists. An increase in the intercentroid (scaphoid/lunate) distance was most evident with the wrist in 20 degrees extension, neutral radioulnar deviation, and 90 degrees supination.  相似文献   
7.
Bacteroides fragilis constitutes about 1% of the bacterial flora in intestines of normal humans. Enterotoxigenic strains of B. fragilis have been associated with diarrheal diseases in humans and animals. The enterotoxin produced by these isolates induces fluid changes in ligated intestinal loops and an in vitro cytotoxic response in HT-29 cells. We developed a nested PCR to detect the enterotoxin gene of B. fragilis in stool specimens. After DNA extraction, a 367-bp fragment was amplified with two outer primers. The amplicon from this reaction was subjected to a second round of amplification with a set of internal primers. With these inner primers, a 290-bp DNA fragment was obtained which was confirmed as part of the B. fragilis enterotoxin gene by Southern blotting with a nonradioactive internal probe and a chemiluminescence system. By this approach, B. fragilis enterotoxin gene sequences were detected in eight known enterotoxigenic human isolates and nine enterotoxigenic horse isolates. No amplification products were obtained from DNA extracted from 28 nonenterotoxigenic B. fragilis isolates or B. distasonis, B. thetaiotaomicron, B. uniformis, B. ovatus, Escherichia coli, or Clostridium difficile. The sensitivity of this assay allowed us to detect as little as 1 pg of enterotoxin DNA sequences or 100 to 1,000 cells of enterotoxigenic B. fragilis/g of stool. Enterotoxin production of all isolates was confirmed in vitro in HT-29 cells. A 100% correlation was obtained between enterotoxin detection by cytotoxin assay and the nested PCR assay. This rapid and sensitive assay can be used to identify enterotoxigenic B. fragilis and may be used clinically to determine the role of B. fragilis in diarrheal diseases.  相似文献   
8.
表小檗碱对α受体的作用   总被引:2,自引:0,他引:2  
王嘉陵  方达超 《药学学报》1990,25(4):289-292
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择  相似文献   
9.
The purpose of this pilot study was to observe both relaxed and deep breathing patterns in a convenience sample to determine the incidence of normal versus faulty patterns of respiration. These observations were then combined with respondent answers to a survey on pain history to determine if there is any correlation between faulty breathing and musculo-skeletal pain patterns. If such a correlation can be made, then we propose that clinicians working with chronic pain patients may have improved outcomes if they address and correct faulty breathing patterns. Based on this study, it is suggested to include the evaluation and treatment of faulty respiration in the rehabilitation of chronic musculo-skeletal conditions, most notably cervical pain.  相似文献   
10.
36例踝关节骨折合并下胫腓联合分离的治疗体会   总被引:1,自引:1,他引:0  
李得春 《医学争鸣》2005,26(17):1631-1631
0 引言 踝关节骨折是临床上较常见的关节内骨折,包含了腓骨骨折,内踝骨折,后踝骨折和下胫腓联合的损伤. 处理不当可导致踝穴的变形,下胫腓联合分离后期出现创伤性关节炎.  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