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   1670篇
  免费   72篇
  国内免费   15篇
耳鼻咽喉   15篇
儿科学   32篇
妇产科学   33篇
基础医学   170篇
口腔科学   62篇
临床医学   93篇
内科学   375篇
皮肤病学   87篇
神经病学   222篇
特种医学   47篇
外科学   232篇
综合类   9篇
预防医学   72篇
眼科学   25篇
药学   86篇
中国医学   4篇
肿瘤学   193篇
  2023年   7篇
  2022年   23篇
  2021年   31篇
  2020年   28篇
  2019年   27篇
  2018年   31篇
  2017年   21篇
  2016年   37篇
  2015年   31篇
  2014年   33篇
  2013年   48篇
  2012年   110篇
  2011年   144篇
  2010年   71篇
  2009年   61篇
  2008年   113篇
  2007年   112篇
  2006年   99篇
  2005年   96篇
  2004年   115篇
  2003年   99篇
  2002年   90篇
  2001年   25篇
  2000年   20篇
  1999年   26篇
  1998年   21篇
  1997年   18篇
  1996年   25篇
  1995年   18篇
  1994年   21篇
  1993年   25篇
  1992年   11篇
  1991年   18篇
  1990年   8篇
  1989年   15篇
  1988年   8篇
  1987年   8篇
  1986年   3篇
  1985年   8篇
  1984年   6篇
  1983年   2篇
  1982年   5篇
  1981年   10篇
  1980年   4篇
  1978年   3篇
  1977年   2篇
  1976年   3篇
  1975年   3篇
  1970年   5篇
  1968年   3篇
排序方式: 共有1757条查询结果,搜索用时 62 毫秒
71.
The interaction of CD47 and signal-regulatory protein alpha (SIRPα) induces “don't eat me signal”, leading suppression of phagocytosis. This signal can affect the clinical course of malignant disease. Although CD47 and SIRPα expression are associated with clinicopathological features in several neoplasms, the investigation for adult T-cell leukemia/lymphoma (ATLL) has not been well-documented. This study aimed to declare the association between CD47 and SIRPα expression and clinicopathological features in ATLL. We performed immunostaining on 73 biopsy samples and found that CD47 is primarily expressed in tumor cells, while SIRPα is expressed in non-neoplastic stromal cells. CD47 positive cases showed significantly higher FoxP3 (P = .0232) and lower CCR4 (P = .0214). SIRPα positive cases presented significantly better overall survival than SIRPα negative cases (P = .0132). SIRPα positive cases showed significantly HLA class I (P = .0062), HLA class II (P = .0133), microenvironment PD-L1 (miPD-L1) (P = .0032), and FoxP3 (P = .0229) positivity. In univariate analysis, SIRPα expression was significantly related to prognosis (Hazard ratio [HR] 0.470; 95% confidence interval [CI] 0.253-0.870; P = .0167], although multivariate analysis did not show SIPRα as an independent prognostic factor. The expression of SIRPα on stromal cells reflects activated immune surveillance mechanism in tumor microenvironment and induce good prognosis in ATLL. More detailed studies for gene expression or genomic abnormalities will disclose clinical and biological significance of the CD47 and SIRPα in ATLL.  相似文献   
72.

Background

It is controversial whether patients with gastric marginal zone lymphomas of mucosa associated lymphoid tissue (MALT) have higher risk of second malignancies. The aim of this study was to define the risk of second malignancies in these patients.

Methods

We analyzed prospective follow-up data of 146 consecutive patients with gastric MALT lymphoma treated at Aichi Cancer Center Hospital and compared the incidence of second malignancies with that in the general population. We calculated the standardized incidence ratio (SIR), using age- and sex-specific incidence rates from the Aichi Cancer Registry.

Results

The median follow-up period was 74 months. A total of 27 tumors occurred in 22 patients (15.1 %), including 19 solid tumors. Of these, nine tumors were detected concomitantly with, and 18 tumors following, the diagnosis of gastric MALT lymphoma. Four patients had two second malignancies each. For the entire group, the SIR of an additional malignancy was 3.39 (95 % confidence interval [CI] 2.11–4.66). An increased incidence of solid tumors (SIR 2.91 [1.60–4.22]) and hematologic malignancies (SIR 5.54 [1.70–9.38]) were seen. In addition, there was increased risk for development of second malignancies during follow up (SIR 2.26 [1.21–3.30]). Chemotherapy for treatment of MALT was an independent risk factor for second malignancies (age–sex adjusted hazard ratio 3.98 [1.47–10.79].

Conclusions

Compared with the general population, patients with gastric MALT lymphoma are at increased risk for second malignancies, including gastric cancer.  相似文献   
73.
74.

Objective

Previous studies have demonstrated the relationship between ageing and oxidative stress. In this study, we examined the effects of topical application of a dentifrice containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) to the gingival surface on gingival collagen degradation in rats.

Design

Fischer 344 male rats (4 or 8 months old) were divided into two groups: experimental group and control group. Tomarina® (the experimental group) or control dentifrice (the control group) was applied 5 days per week for 2 months.

Results

In the control group, gingival collagen density decreased with ageing. In the experimental group, the collagen density did not change with ageing, and was greater than that in the control group at 10 months of age (p < 0.0083). In addition, the control group showed an increase in serum oxidative stress with ageing. The experimental group also showed increased serum oxidative stress, but the value was lower than the control group at 10 months of age (p < 0.0083). Furthermore, low expressions of protein oxidative damage in the periodontal tissue were observed in the experimental group, compared to the control group at 6 months and 10 months.

Conclusion

These findings indicate that Tomarina® might suppress the effects of ageing on gingival collagen degradation, by decreasing oxidative stress in the rat model.  相似文献   
75.
76.
Background: It has been reported that cystine and theanine, amino acids related to glutathione synthesis, have immunomodulatory effects, such as suppressing inflammation after strenuous exercise. In this study, we examined the effects of oral administration of cystine and theanine during the perioperative period as a pilot study. Methods: Forty‐three cases of distal gastrectomy for cancer conducted in our department were assigned to the cystine and theanine group (CT group) or to the placebo control group (P group), and a randomized, single‐blind, parallel‐group study was then performed. Cystine (700 mg) and theanine (280 mg) or a placebo was administered to participants for 10 continuous days (4 days before to 5 days after surgery). Changes in pre‐ and postoperative interleukin (IL)–6, C‐reactive protein (CRP), albumin, white blood cell (WBC) count, neutrophil count, total lymphocyte count, resting energy expenditure (REE), and body temperature were compared and examined. Results: Ten patients were excluded, leaving 33 patients in the study. The CT group had significantly lower IL‐6 values (postoperative day [POD] 4), CRP levels (POD 7), neutrophil counts (POD 4), and body temperatures (POD 5) than the P group (P < .05). In addition, REE in the P group peaked on day 1 (1.14 ± 0.16 [pre‐ and postoperative ratio]), whereas the CT group did not show any increase on POD 1 (0.99 ± 0.21, P < .05 vs P group). Conclusions: This study suggests that oral administration of cystine and theanine during the perioperative period may alleviate postgastrectomy inflammation and promote recovery after surgery.  相似文献   
77.
The etiology of autism is unclear, however autism is considered as a multifactorial disorder that is influenced by neurological, environmental, immunological and genetic factors. Growth factors, including epidermal growth factor (EGF), play an important role in the celluler proliferation and the differentiation of the central and peripheral nervous system. In this study we hypothesized that EGF may play a role in the pathophysiology of autism and examined serum EGF levels in children with autism. We measured serum levels of EGF in the 27 autistic children and 28 age- matched normal controls. The serum levels of EGF in the subjects with autism were significantly higher than those of normal control subjects. However, there were no correlations between serum EGF levels and clinical variables in the subjects with autism. This is the first report demonstrating the increased serum levels of EGF in children with autism. This study suggests that increased levels of EGF might have an importance in the pathophysiology of autism.  相似文献   
78.
79.
80.
PURPOSE: Severe acute radiation dermatitis is observed in approximately 5% to 10% of patients who receive whole-breast radiotherapy. Several factors, including treatment-related and patient-oriented factors, are involved in susceptibility to severe dermatitis. Genetic factors are also thought to be related to a patient's susceptibility to severe dermatitis. To elucidate genetic polymorphisms associated with a susceptibility to radiation-induced dermatitis, a large-scale single-nucleotide polymorphism (SNP) analysis using DNA samples from 156 patients with breast cancer was conducted. EXPERIMENTAL DESIGN: Patients were selected from more than 3,000 female patients with early breast cancer who received radiotherapy after undergoing breast-conserving surgery. The dermatitis group was defined as patients who developed dermatitis at a National Cancer Institute Common Toxicity Criteria grade of > or =2. For the SNP analysis, DNA samples from each patient were subjected to the genotyping of 3,144 SNPs covering 494 genes. RESULTS: SNPs that mapped to two genes, ABCA1 and IL12RB2, were associated with radiation-induced dermatitis. In the ABCA1 gene, one of these SNPs was a nonsynonymous coding SNP causing R219K (P = 0.0065). As for the IL12RB2 gene, the strongest association was observed at SNP-K (rs3790568; P = 0.0013). Using polymorphisms of both genes, the probability of severe dermatitis was estimated for each combination of genotypes. These analyses showed that individuals carrying a combination of genotypes accounting for 14.7% of the Japanese population have the highest probability of developing radiation-induced dermatitis. CONCLUSION: Our results shed light on the mechanisms responsible for radiation-induced dermatitis. These results may also contribute to the individualization of radiotherapy.  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