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   390篇
  免费   24篇
  国内免费   33篇
耳鼻咽喉   9篇
儿科学   61篇
妇产科学   3篇
基础医学   18篇
口腔科学   13篇
临床医学   54篇
内科学   80篇
皮肤病学   2篇
神经病学   26篇
特种医学   58篇
外科学   18篇
综合类   19篇
预防医学   14篇
眼科学   4篇
药学   45篇
中国医学   1篇
肿瘤学   22篇
  2022年   2篇
  2021年   4篇
  2019年   5篇
  2018年   6篇
  2017年   5篇
  2016年   4篇
  2015年   4篇
  2014年   10篇
  2013年   15篇
  2012年   9篇
  2011年   8篇
  2010年   18篇
  2009年   21篇
  2008年   18篇
  2007年   23篇
  2006年   12篇
  2005年   10篇
  2004年   6篇
  2003年   7篇
  2002年   9篇
  2001年   5篇
  2000年   5篇
  1999年   13篇
  1998年   14篇
  1997年   18篇
  1996年   15篇
  1995年   13篇
  1994年   23篇
  1993年   15篇
  1992年   11篇
  1991年   11篇
  1990年   4篇
  1989年   12篇
  1988年   7篇
  1987年   9篇
  1986年   9篇
  1985年   8篇
  1984年   4篇
  1983年   3篇
  1982年   5篇
  1981年   12篇
  1980年   2篇
  1979年   2篇
  1977年   6篇
  1976年   4篇
  1975年   6篇
  1974年   2篇
  1971年   3篇
  1970年   5篇
  1968年   1篇
排序方式: 共有447条查询结果,搜索用时 15 毫秒
1.
Neuroimaging in Pineal Tumors   总被引:4,自引:0,他引:4  
F Reis  MD  AV Faria  MD  PhD  VA Zanardi  MD  PhD  JR Menezes  MD  F Cendes  MD  PhD  LS Queiroz  MD  PhD 《Journal of neuroimaging》2006,16(1):52-58
BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.  相似文献   
2.
中药材龟板和鳖甲中DNA的提取与扩增   总被引:22,自引:0,他引:22  
中药材龟板和鳖甲中DNA的提取与扩增王亚明,周开亚,吴平,徐珞珊(南京师范大学生物系,南京210097;中国药科大学生药学研究室,南京210009)龟鳖类药材在我国使用历史悠久,具补阴益气的功效。《中国药典》(1990年版)规定龟甲(龟板)的原动物为...  相似文献   
3.
4.
BACKGROUNDPrimary extra-gastrointestinal stromal tumors (E-GIST) of the liver are rare. The clinical presentation may range from asymptomatic to bleeding or manifestations of mass effect. Oncologic surgery followed by adjuvant therapy with imatinib is the standard of care. However, under specific circumstances, a cytoreductive approach may represent a therapeutic option. We describe herein the case of an 84-year-old woman who presented with a tender, protruding epigastric mass. Abdominal computed tomography scan revealed a large, heterogeneous mass located across segments III, IV, V, and VIII of the liver. The initial approach was transarterial embolization of the tumor, which elicited no appreciable response. Considering the large size and central location of the tumor and the advanced age of the patient, non-anatomic complete resection was indicated. Due to substantial intraoperative bleeding and hemodynamic instability, only a near-complete resection could be achieved. Histopathology and immunohistochemical staining confirmed the diagnosis of primary E-GIST of the liver. Considering the risk/benefit ratio for therapeutic options, debulking surgery may represent a strategy to control pain and prolong survival.CASE SUMMARYHere, we present a case report of a patient diagnosed with E-GIST primary of the liver, which was indicated a cytoreductive surgery and adjuvant therapy with imatinib.CONCLUSIONE-GIST primary of the liver is a rare conditional, the treatment is with systemic therapy and total resection surgery. However, a cytoreductive surgery will be necessary when a complete resection is no possible.  相似文献   
5.
The clinic-epidemiologic and prognostic features of 424 cases of Ewing sarcoma observed at "Rizzoli" Institute between 1972-1990 are reported. The incidence of the tumor was higher in the second decade of life with slight predominance in the male sex. The primary lesion was especially localized in the extremity and the ratio lower/upper extremity was 5/1. We did not find, in contrast with other Authors, differences in height or in incidence of congenital malformations when compared to controls. The pain was the first common symptom at debut (90%) followed by swelling (50%) and fever (40%). Diagnosis was made 5.5 months after the first symptom and the delay was due to wrong diagnosis at debut in 3/4 of the patients. Laboratory tests showed anemia in about half of the patients and increased value of ESR (60%) and LDH (40%). Seventy-one of the patients were metastatic at presentation, none of these patients were still living after three years. At a median follow-up of 9 years 43% of the patients with localized disease, treated with adjuvant and neo-adjuvant chemotherapy remained continuously disease free, 53% developed metastatic disease and/or local recurrences and 2% had a second malignancy. In 24% of the patients metastases and/or local recurrences appeared three years after the beginning of treatment. Better prognosis was observed in female patients, without fever at diagnosis, with tumor localized at extremities and with normal value of hemoglobin, ERS and LDH. Regarding the type of treatment, better results were obtained by surgery of the primary tumor and by chemotherapy with four drugs (vincristine, cyclophosphamide, adriamycin dactinomycin) in comparison to radiotherapy of the primary tumor and chemotherapy with three drugs (vincristine, cyclophosphamide, adriamycin).  相似文献   
6.
7.
To express the core protein of HIV-1 of Chinese prevalent strain (HIV-1 (CN)) in Pichia pastoris, the fulllength gag gene was inserted into the secretory expression vector pHILS1. Linearized recombinant plasmid pHILGAG by Sail was electrotransformed into the yeast strain GS115, and the yeast transformants were identified by PCR. To induce the interest protein to be expressed, the PCR positive transformants were inoculated in the medium of BMGY and BMMY, mRNA of the strain was detected by RT-PCR, and the expressed protein was analyzed by SDS-PAGE, Western blotting and thin layer scanning. mRNA (1.3 kb) was amplified by RT-PCR. SDS-PAGE and Western blotting analysis showed that the molecular mass of the expressed protein was 55 kD, which was similar to the expected value, and the expressed protein could react with McAb to HIV-1 p24. Thin layer scanning analysis demonstrated that the whole amount of the expressed protein was approximately 13 % of the soluble protein in the supernatant. The recombinant yeast had good genetic stability. The optimal expression conditions of the engineering yeast were as follows: BMMY medium, 80-90% of dissolved oxygen, 1% methanol, and 3-day-cultivation course. Gag proteins were expressed under the optimal expression condition and purified via gel filtration chromatography. The purity of the interest protein was up to 85 %. After the purified proteins were inoculated into BALB/c mice, the anti-HIV-1 antibodies in the immunized mice could be detected by Western blotting.  相似文献   
8.
The development of colonoscopy with image magnification has enable to study the colonic mucosa in detail and to do differential diagnosis between neoplastic and non-neoplastic lesions from the observation of pit patterns. The results are comparable to stereomicroscopy being possible to predict the histologic diagnosis. In a patient with familial adenomatous polyposis magnifying colonoscopy was performed and this method demonstrated a wide variation of benign polypoid lesions and the morphological features of early colorectal cancer. In this patient, the evaluation by image magnification, together with indigo carmin 0.4% chromoscopy, showed a wide variety of lesions in the colon and rectum: laterally spreading tumor in the cecum, with IIIL + IV pits, subpediculate polyp in the transverse colon with approximately 2.0 cm diameter and IV + V pits, flat elevated lesions IIIL type, and in the sigmoid colon IIa + IIc lesion with V type of Kudo's classification were observed. The evaluation of pit patterns of the lesions in the transverse and sigmoid colon has enable to do the endoscopic diagnosis of the lesion with submucosal invasion.  相似文献   
9.
10.
Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries.  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