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   633篇
  免费   37篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   19篇
妇产科学   5篇
基础医学   114篇
口腔科学   16篇
临床医学   49篇
内科学   204篇
皮肤病学   7篇
神经病学   25篇
特种医学   26篇
外科学   61篇
预防医学   12篇
眼科学   8篇
药学   38篇
中国医学   2篇
肿瘤学   85篇
  2023年   10篇
  2022年   13篇
  2021年   13篇
  2020年   13篇
  2019年   6篇
  2018年   8篇
  2017年   9篇
  2016年   10篇
  2015年   6篇
  2014年   20篇
  2013年   8篇
  2012年   23篇
  2011年   42篇
  2010年   18篇
  2009年   11篇
  2008年   35篇
  2007年   37篇
  2006年   33篇
  2005年   31篇
  2004年   28篇
  2003年   29篇
  2002年   31篇
  2001年   13篇
  2000年   13篇
  1999年   14篇
  1998年   5篇
  1997年   6篇
  1996年   13篇
  1995年   8篇
  1994年   5篇
  1993年   16篇
  1992年   17篇
  1991年   16篇
  1990年   6篇
  1989年   19篇
  1988年   11篇
  1987年   3篇
  1986年   10篇
  1985年   7篇
  1984年   8篇
  1983年   5篇
  1981年   5篇
  1979年   5篇
  1975年   3篇
  1974年   6篇
  1973年   5篇
  1971年   2篇
  1970年   2篇
  1969年   2篇
  1923年   2篇
排序方式: 共有672条查询结果,搜索用时 15 毫秒
51.
Loss of heterozygosity (LOH) correlates with inactivate tumor suppressor gene. The aim of this study was to see if LOH on chromosomes 2q, 3p and 21q correlated with a poor prognostic factor in oral squamous cell carcinoma (SCC). We analyzed chromosomes 2q, 3p and 21q for LOH in 40 primary oral SCCs using 30 markers and constructed a deletion map for these chromosome arms. Significant LOH (>20%) occurred at alleles in chromosome bands 2q14–21 (21.7%), 2q32–35 (31.6%), 2q35 (21.1%), 2q36 (36.7%), 3p25 (32.4%), 3p21.3 (23.8%), 21q11.1 (52.4%), 21q21 (21.6%) and 21q22.1 (22.2%). A significant correlation was observed between the number of regions showing LOH at 2q and TNM clinical stage (P=0.0063), consistent with the progressive accumulation of genetic errors during the development oral SCC. The number at more than two LOH loci was significant with a poor prognosis at 2q (P=0.0208). These findings demonstrate that oral SCC exhibits genetic alterations at multiple loci and that allelic loss at more than two locations is indicative of a poor prognosis. This is the first study to demonstrate the prognostic significance of LOH at 2q, 3p and 21q for oral cancer and may help to identify patient who should receive more aggressive treatment.  相似文献   
52.
The nitric acid muscle fiber digestion method has generally been used to determine total numbers of muscle fibers and branched fibers. However, it is not suitable for further studies because nitric acid causes protein denaturation known as the xanthoproteic reaction which make it difficult to examine the fiber types and morphology of muscle fibers. Therefore, we attempted to modify this method to preserve the morphology of muscle fibers as much as possible. Our modifications were as follows: (1) samples were immersed in ion exchanged water before nitroc acid treatment; (2) mammalian relaxing solution was used as the post- incubation solution; (3) the temperature of nitric acid was maintained at 4 degrees C; and (4) the nitric acid concentration was reduced to 10% from 15%. The samples obtained by this method were stained with phosphotungstic acid-hematoxylin and their striations were examined by a differential interference contrast method using light microscopy. The cell organella i.e. actin filaments, myosin filaments, T-tubules and mitochondria, were also examined electron microscopy. Actin and myosin filaments in these samples were also stained immunohistochemically to clarify the preservation of antigenicity. As a result, this modified method made it possible to examine actin and myosin filaments of a single muscle fiber light-microscopically and immunohistochemically and also to examine cell organella of a single muscle by electron microscopy. These results indicate that our method is useful for studies on branched muscle fibers such as stereological analysis and innervation of a single branched muscle fiber, in addition to obtaining muscle fiber numbers.  相似文献   
53.
Total intravenous anesthesia (TIVA) has been recommended in view of avoiding air pollution. However, intermittent administration of anesthetic agents has a large disadvantage of delayed emergence time. We reported that continuous TIVA with propofol, ketamine, vecuronium and buprenorphine (PKBp) could bring rapid emergence time. An 8-year old female with spinal scoliosis underwent spinal instrumentation under continuous TIVA. Wake-up test was done twice during surgery smoothly after stopping infusion of anesthetic agents in the cocktail. We conclude that continuous TIVA is one of the most recommended anesthetic methods for wake-up test.  相似文献   
54.
55.
56.
57.
Ganciclovir resistance in cytomegalovirus (CMV) is an increasing problem in lung-transplant recipients with adverse clinical outcomes. We experienced the successful treatment of ganciclovir-resistant CMV infection in a lung-transplant recipient still receiving CMV prophylaxis. A 24-year-old woman with lymphangioleiomyomatosis underwent a living-donor lobar lung transplantation. She was a primary CMV mismatch (D+/R-) patient. She recovered from her postoperative complications, and was about to be discharged. However, she suffered ganciclovir-resistant CMV infection during prophylactic therapy. She was successfully treated with foscarnet, and is now alive without recurrence 18 months after surgery.  相似文献   
58.
OBJECTIVES: To study the characteristics of bone or joint tuberculosis (TB) accompanied by TB in other organs (especially the lung), and to study patients' and doctors' delay in detecting bone or joint TB. SUBJECTS AND METHODS: A retrospective study was conducted on 33 patients with bone or joint TB concurrent with TB of other organs, especially the lung, who were admitted to our hospital between 1981 and 2005. The patients were divided into the following three groups according to the organ of concurrent TB : (1) miliary TB group (N = 10), (2) pulmonary TB group (N = 19), and (3) other TB site group (N = 4). The relationship between bone/joint TB and TB of other organs was studied by comparing the three groups with respect to the time of appearance of musculo-skeletal symptoms or signs such as swelling and pain and that of symptoms or signs originating from other organs, such as cough, sputum, miliary pattern on chest radiograph and superficial lymph node swelling. RESULTS: The mean age (SD) of patients was 50.5 (18.9) yr, and the male to female ratio was 23 : 10. Among 33 patients, bone TB (including 18 spinal TB) was detected in 24 patients, joint TB in 14, and abscess in 3 (concurrent lesions in some patients). The mean intervals from onset of symptoms to consultation (patients' delay), from consultation to diagnosis (doctors' delay) and from symptom onset to diagnosis (total delay) were 5.5 (13.9), 3.4 (5.2) and 8.9 (13.9) months, respectively. (1) Bone/joint TB concurrent with miliary TB (N = 10) In 8 patients with mean age of 61.0 (17.4) yr, musculo-skeletal symptoms/signs preceded respiratory symptoms or appearance of miliary pattern on chest radiograph by 7.8 (7.2) (range; 1-24) months. The patients', doctors' and total delays were 0.4 (0.5), 7.3 (7.8), and 7.7 (7.6) months, respectively. In most cases, bone/joint TB was diagnosed after the onset of miliary pattern on chest radiograph. In one patient with simultaneous onset of musculo-skeletal and respiratory symptoms/signs (age 21 yr), the interval of total delay was 1 month, and in one patient with musculoskeletal symptoms which appeared six months later than respiratory symptoms (age 28 yr), the interval of total delay was 2 months. (2) Bone/joint TB concurrent with active pulmonary TB (N = 19). In this group, the mean age was 52.2 (17.1) yr, and males were predominant (M/F = 15/4). Active pulmonary TB was diagnosed by positive sputum culture in 13 patients, by positive sputum smear or PCR results in 4 patients, and by the clinical course in 2 patients. Ten patients (53%) had a previous TB history. Cavitary lesion was observed in 15 patients, and the upper lobes were predominantly involved on chest radiograph in 19 patients, indicating that the pulmonary TB was probably post-primary (reactivation) in all patients. In 9 patients with mean age of 49.7 (15.7) yr, musculo-skeletal symptoms/signs preceded respiratory symptoms by 14.1 (14.0) (range; 4-48) months. The patients', doctors' and total delays were 13.3 (17.8), 3.8 (6.6), and 17.1 (16.1) months, respectively. On the other hand, in 10 patients with mean age of 54.5 (18.7) yr, musculo-skeletal symptoms/signs and respiratory symptoms/signs appeared simultaneously, and the total delay was 2.7 (1.9) months. Twelve of 19 patients (63%) had complications such as diabetes mellitus, steroid use, and liver diseases. In cases with miliary or pulmonary tuberculosis, the total delay in diagnosis (Y) correlates positively with the time lag from onset of musculo-skeletal symptoms to respiratory symptoms/signs (X), and the regression line (Y = 0.94X + 2.3, r = 0.98, p < 0.001) was almost linear (Y = X), indicating that the diagnosis of bone/joint TB was made just after the diagnosis of miliary or pulmonary TB. (3) Bone/joint TB concurrent with TB of other sites (N = 4) In 2 female cases (21 and 28 yrs) with cervical lymph node TB, musculo-skeletal symptoms/signs and cervical lymph node swelling appeared simultaneously. In a 54-yr male patient, musculo-skeletal symptoms/signs appeared 5 years after appearance of testicular enlargement, and testicular TB was diagnosed by biopsy simultaneously. In a 33 year-old male patient, musculo-skeletal symptoms/signs appeared 7 months after the drainage of pleural and pericardial effusions (TB was not diagnosed initially), and then the diagnosis of bone/joint, pleural, and pericardial tuberculosis was made for the first time. CONCLUSIONS: In middle-aged or elderly patients with active bone/joint TB, miliary TB is sometimes caused by bacillemia originating from the infected bone/joint lesions. In cases with bone/joint TB and concurrent pulmonary TB, bone/joint TB and pulmonary TB are probably reactivated independently as a result of decreased systemic immunocompetence.  相似文献   
59.
60.
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