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   498篇
  免费   10篇
  国内免费   1篇
耳鼻咽喉   14篇
儿科学   10篇
妇产科学   17篇
基础医学   63篇
口腔科学   8篇
临床医学   33篇
内科学   110篇
皮肤病学   17篇
神经病学   66篇
特种医学   13篇
外科学   40篇
综合类   2篇
预防医学   22篇
眼科学   6篇
药学   35篇
肿瘤学   53篇
  2024年   3篇
  2023年   10篇
  2022年   10篇
  2021年   20篇
  2020年   18篇
  2019年   17篇
  2018年   17篇
  2017年   9篇
  2016年   17篇
  2015年   16篇
  2014年   27篇
  2013年   28篇
  2012年   42篇
  2011年   22篇
  2010年   18篇
  2009年   16篇
  2008年   25篇
  2007年   35篇
  2006年   35篇
  2005年   26篇
  2004年   31篇
  2003年   21篇
  2002年   12篇
  2001年   2篇
  1999年   2篇
  1997年   1篇
  1996年   8篇
  1995年   2篇
  1994年   5篇
  1993年   3篇
  1992年   1篇
  1991年   2篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1982年   2篇
  1976年   1篇
排序方式: 共有509条查询结果,搜索用时 0 毫秒
91.
We herein report a case of pigmented condyloma acuminatum in the genital region. A histopathological examination revealed keratinocyte proliferation, papillomatosis and basal pigmentation. Cellular atypia was rarely observed. The patient also had ordinary skin‐colored nodules on the coronal sulcus. Polymerase chain reaction amplification with consensus primers for human papillomavirus (HPV) and subsequent sequencing confirmed an infection of HPV type 6. Pigmented condyloma acuminatum is not rare; however, making the differential diagnosis between bowenoid papulosis and seborrheic keratosis is sometimes difficult. The mechanism of pigmentation in such cases remains unknown and requires further investigation. HPV typing is a useful method for diagnosing the disease.  相似文献   
92.
93.
HIV-1 mutants escaping from HLA-A- or HLA-B-restricted CTL have been well studied, but those from HLA-C-restricted CTL have not. Therefore we investigated the ability of HLA-C-restricted CTL to select HIV-1 escape mutants. In the present study, we identified two novel HLA-Cw(*) 1202-restricted Pol-specific CTL epitopes (Pol328-9 and Pol463-10). CTL specific for these epitopes were detected in 25-40% of chronically HIV-1-infected HLA-Cw(*) 1202(+) individuals and had strong abilities to kill HIV-1-infected cells and to suppress HIV-1 replication in vitro, suggesting that these CTL may have the ability to effectively control HIV-1 in some HLA-Cw(*) 1202(+) individuals. Sequence analysis of these epitopes showed that a V-to-A substitution at the 9th position (V9A) of Pol 463-10 was significantly associated with the HLA-Cw(*) 1202 allele and that the V9A mutant was slowly selected in the HLA-Cw(*) 1202(+) individuals. Pol 463-10-specific CTL failed both to kill the V9A virus-infected cells and to suppress replication of the V9A mutant. These results indicate that the V9A mutation was selected as an escape mutant by the Pol463-10-specific CTL. The present study strongly suggests that some HLA-C-restricted CTL have a strong ability to suppress HIV-1 replication so that they can select HIV escape mutants as in the case of HLA-A-restricted or HLA-B-restricted CTL.  相似文献   
94.
Detection of novel events is crucial for adapting to changing environments. The prefrontal cortex has been thought to be one of the areas involved in orienting attention to novel events. Here, we examined the effects of two components of novelty: context novelty, which purely happens when a familiar event occurs in an unpredicted situation or time and feature novelty, which happens by itself when an unfamiliar stimulus appears against the expectation of familiar ones. We trained monkeys on a task that included both novelty components and recorded the activity of neurons in the lateral and medial divisions of the prefrontal cortex. The responses of a substantial number of cells in both the lateral and medial divisions were enhanced when a familiar visual stimulus was presented in an unpredicted context. By contrast, enhancement of responses by the unfamiliarity of visual stimuli was observed mainly in cells in the lateral prefrontal cortex. These results suggest that the lateral and medial divisions of the prefrontal cortex are differentially involved in the control of attention triggered by novel sensory events.  相似文献   
95.

Background

Skeletal muscle metabolism is a major determinant of resting energy expenditure (REE). Although the severe muscle loss that characterizes Duchenne muscular dystrophy (DMD) may alter REE, this has not been extensively investigated.

Methods

We studied REE in 77 patients with DMD ranging in age from 10 to 37 years using a portable indirect calorimeter, together with several clinical parameters (age, height, body weight (BW), body mass index (BMI), vital capacity (VC), creatine kinase, creatinine, albumin, cholinesterase, prealbumin), and assessed their influence on REE. In addition, in 12 patients maintaining a stable body weight, the ratio of energy intake to REE was calculated and defined as an alternative index for the physical activity level (aPAL).

Results

REE (kcal/day, mean ± SD) in DMD patients was 1123 (10–11 years), 1186 ± 188 (12–14 years), 1146 ± 214 (15–17 years), 1006 ± 136 (18–29 years) and 1023 ± 97 (?30 years), each of these values being significantly lower than the corresponding control (p < 0.0001). VC (p < 0.001) was the parameter most strongly associated with REE, followed by BMI (p < 0.01) and BW (p < 0.05). The calculated aPAL values were 1.61 (10–11 years), 1.19 (12–14 years), 1.16 (15–17 years), and 1.57 (18–29 years).

Conclusion

The REE in DMD patients was significantly lower than the normal value in every age group, and strongly associated with VC. Both the low REE and PAL values during the early teens, resulting in a low energy requirement, might be related to the obesity that frequently occurs in this age group. In contrast, the high PAL value in the late stage of the disease, possibly due to the presence of respiratory failure, may lead to a high energy requirement, and thus become one of the risk factors for development of malnutrition.  相似文献   
96.
A large portosystemic shunt between the inferior mesenteric vein and the right internal iliac vein in a 28-yr-old non-cirrhotic man is presented. This collateral was discovered by ultrasound done as a screening examination for gastrointestinal bleeding. The direct communication of the inferior mesenteric vein with the internal iliac vein was demonstrated by computed tomography and percutaneous transhepatic portography. Surgical ligation of the collateral, performed to prevent future portosystemic encephalopathy, resulted in reduction of serum ammonia level and cessation of long-standing hemorrhoidal bleeding.  相似文献   
97.
We present a case of carcinoma ex pleomorphic adenoma on the right buccal mucosa in a 52-year-old Japanese woman. Based on the histopathology, the excised tumor was the non-invasive type, but the majority of the tumor consisted of poorly-differentiated adenocarcinoma cells. We performed proton radiation after the surgery. The patient was well, without evidence of disease, 48 months after surgery. Carcinoma ex pleomorphic adenoma in the buccal mucosa has been reported in only four cases during the past twenty years. Therefore, our case was comparatively rare.  相似文献   
98.
GNE myopathy is a rare and mildly progressive autosomal recessive myopathy caused by GNE mutations. Respiratory dysfunction has not been reported in GNE myopathy patients. In this study, we retrospectively reviewed the respiratory function of 39 severely affected GNE myopathy patients (13 men, 26 women) from medical records, and compared these parameters with various other patient characteristics (e.g., GNE mutations, age at onset, creatine kinase levels, and being wheelchair-bound) for correlations. The mean % forced vital capacity [FVC] was 92 (26) (range, 16–128). In 12/39 (31%) patients, %FVC was <80%. Of these 12 patients, 11 (92%) were entirely wheelchair-dependent. These patients exhibited significantly earlier onset (20 [4] vs. 30 [8] years, p < 0.001) and lower creatine kinase levels (56 [71] vs. 279 [185] IU/L) than patients with normal respiratory function. Two patients exhibited severe respiratory failure and required non-invasive positive pressure ventilation. Patients with a homozygous mutation in the N-acetylmannosamine kinase domain exhibited lower %FVC, while only one compound heterozygous patient with separate mutations in the uridinediphosphate-N-acetylglucosamine 2-epimerase and the N-acetylmannosamine kinase domains had respiratory dysfunction. Our results collectively suggest that GNE myopathy can cause severe respiratory failure. Respiratory dysfunction should be carefully monitored in patients with advanced GNE myopathy characterized by early onset and homozygous homozygous mutations in the N-acetylmannosamine kinase domain.  相似文献   
99.
PURPOSE: The purpose of this study was to evaluate the usefulness of CT or MR imaging findings in patients with spinal epidural hematoma (SEH) for predicting neurological outcome. MATERIALS AND METHODS: MR images of our six patients with SEH were evaluated retrospectively: complete recovery was achieved in two patients; paresis remained in two patients; and paraplegia remained in two patients. The ratio of the maximum anteroposterior diameter of the SEH to that of the spinal canal was calculated in each patient on midline on axial images in our six patients and 23 previously reported patients. RESULTS: Among our six patients, the ratio was less than 60% in two patients with total recovery, whereas all four patients with remaining motor impairment had ratios of 60% or more. Of 29 cases, 18 of 22 patients without residual motor impairment had ratios of less than 60%, but five of seven patients with residual motor deficits had ratios of 60% or more (p = 0.023). CONCLUSION: The degree of spinal cord compression by hematoma may be a prognostic factor in SEH.  相似文献   
100.
It is sometimes difficult to discriminate high functioning pervasive developmental disorders (HFPDD) from attention deficit/hyperactivity disorders (AD/HD) in young children because of the behavioral similarities between the two. For adequate diagnosis, understanding fundamental differences in their social cognitive abilities might become significant. In order to detect the differences in social cognitive abilities between AD/HD and HFPDD, a new test, the Metaphor and Sarcasm Scenario Test (MSST) was developed. One hundred and ninety-nine normal school children (the control group), 29 AD/HD children and 54 HFPDD children were involved. The results showed that the inability to understand a sarcastic situation was specific to children with HFPDD, both children with AD/HD and HFPDD could not equally understand metaphor. The correlation between the comprehension of sarcasm and success in the theory of mind task was remarkably high but not for comprehension of metaphor. In conclusion, the MSST has the potential to discriminate HFPDD from AD/HD in young children.  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