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   5195篇
  免费   213篇
  国内免费   27篇
耳鼻咽喉   48篇
儿科学   66篇
妇产科学   25篇
基础医学   534篇
口腔科学   142篇
临床医学   236篇
内科学   1079篇
皮肤病学   370篇
神经病学   311篇
特种医学   534篇
外科学   853篇
综合类   10篇
一般理论   1篇
预防医学   164篇
眼科学   142篇
药学   271篇
中国医学   13篇
肿瘤学   636篇
  2023年   34篇
  2022年   16篇
  2021年   93篇
  2020年   54篇
  2019年   72篇
  2018年   96篇
  2017年   89篇
  2016年   98篇
  2015年   100篇
  2014年   146篇
  2013年   174篇
  2012年   277篇
  2011年   333篇
  2010年   154篇
  2009年   134篇
  2008年   255篇
  2007年   273篇
  2006年   308篇
  2005年   244篇
  2004年   226篇
  2003年   243篇
  2002年   239篇
  2001年   168篇
  2000年   145篇
  1999年   183篇
  1998年   59篇
  1997年   46篇
  1996年   41篇
  1995年   33篇
  1994年   35篇
  1993年   32篇
  1992年   114篇
  1991年   117篇
  1990年   85篇
  1989年   73篇
  1988年   91篇
  1987年   79篇
  1986年   56篇
  1985年   85篇
  1984年   63篇
  1983年   33篇
  1982年   15篇
  1981年   17篇
  1979年   23篇
  1978年   19篇
  1977年   17篇
  1970年   16篇
  1968年   22篇
  1967年   14篇
  1966年   15篇
排序方式: 共有5435条查询结果,搜索用时 140 毫秒
1.
Family history (FH) of cancer is an important factor of increased risk of several cancers. Although the association between FH of cancer and concordant cancer risk has been reported in many previous epidemiological studies, no comprehensive prospective study with adjustment for lifestyle habits has evaluated the association of FH of cancer and concordant cancer risk. We investigated the association between FH of cancer and concordant cancer risk in a Japanese population-based prospective study, initiated in 1990 for cohort I and in 1993 for cohort II. We analyzed data on 103,707 eligible subjects without a history of cancer who responded to a self-administered questionnaire including FH of cancer at baseline. Study subjects were followed through 2012 and analyzed using multivariable-adjusted Cox proportional hazards regression models. During 1,802,581 person-years of follow-up, a total of 16,336 newly diagnosed cancers were identified. Any site (Hazard ratios = 1.11 (95% confidence interval = 1.07–1.15]), esophagus (2.11 [1.00–4.45]), stomach (1.36 [1.19–1.55]), liver (1.69 [1.10–2.61]), pancreas (2.63 [1.45–4.79]), lung (1.51 [1.14–2.00]), uterus (1.93 [1.06–3.51]) and bladder cancers (6.06 [2.49–14.74]) with FH of the concordant cancer were associated with an increased risk compared to those without FH. Our findings suggest that having FH of cancer is associated with an increased risk of several concordant cancer incidences in an Asian population. Enquiring about FH of several types of cancer may be important in identifying groups at high-risk of those cancers.  相似文献   
2.
The aim of this study was to evaluate whether the lesion regression rate (ΔLR) based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria could be used for the prediction of treatment outcome in head and neck squamous cell carcinoma (HNSCC) patients treated with chemoradiotherapy (CRT) compared with FDG PET-CT. A total of 33 patients underwent MRI and PET-CT at pretreatment and at 8 weeks after CRT. We assessed the treatment outcome by analyzing the following parameters: the RECIST criteria, ΔLR, the European Organization for Research and Treatment of Cancer (EORTC) criteria, and pretreatment SUVmax of the primary tumor and node. The correlation between the analysis of the parameters and the results of the long-term follow-up of the patients was determined. The RECIST did not significantly correlate with locoregional control (LRC) or survival. The ΔLR was significantly lower for the lesions with locoregional failure (LRF) than for those with LRC. A threshold ΔLR of 48% revealed a sensitivity of 72.7% and specificity of 77.3% for the prediction of LRF. Progression-free survival (PFS) of patients with ΔLR ≥ 48% was significantly better than that of patients with ΔLR < 48% (P = 0.001), but not overall survival. There was a significant correlation between LRC and the EORTC (P = 0.02). The patients who achieved a complete response by the EORTC criteria showed significantly better PFS and overall survival (P = 0.01 and 0.04, respectively). The ΔLR was inferior to FDG PET-CT with respect to the prediction of patient survival; however, it may be useful for selecting patients in need of more aggressive monitoring after CRT.  相似文献   
3.
We report an 80-year-old Japanese male with four primary malignant tumors: malignant melanoma, prostatic cancer, malignant lymphoma, and renal cell carcinoma, which occurred in that respective order. The combination of malignant melanoma and malignant lymphoma is rare. The patient was treated with BCG after an operation for malignant melanoma. He was also treated with cobalt 60 irradiation after an operation for prostatic cancer. We also discuss other reports of multiple malignant tumors and suggest some possible causes of this patient's primary malignant tumors.  相似文献   
4.
Big mitogen-activated protein kinase 1 (BMK1), also known as extracellular signal-regulated kinase 5 (ERK5), is a newly identified member of the mitogen-activated protein (MAP) kinase family. Recently, several studies have suggested that BMK1 plays an important role in the pathogenesis of cardiovascular disease. To clarify the pathophysiological significance of BMK1 in the process of vascular remodeling, we explored the molecular mechanisms of BMK1 activation in vascular smooth muscle cells (VSMCs). From the results of co-immunoprecipitation and immunoblotting analyses, it was found that platelet-derived growth factor (PDGF), a known potent mitogen, activated BMK1 and triggered the Gab1-SHP-2 interaction in rat aortic smooth muscle cells (RASMCs). The abrogation of SHP-2 phosphatase activity by transfection of the SHP-2-C/S mutant suppressed PDGF-stimulated BMK1 activation. Infection with an adenoviral vector expressing dominant-negative MEK5alpha, which can suppress PDGF-stimulated BMK1 activation to the control level, inhibited PDGF-induced RASMC migration. Moreover, we observed an increase of BMK1 activation in injured mouse femoral arteries. From these findings, it is suggested that BMK1 activation leads to VSMC migration induced by PDGF via Gab1-SHP-2 interaction, and that BMK1-mediated VSMC migration may play a role in the pathogenesis of vascular remodeling.  相似文献   
5.
6.
7.
8.
In order to investigate the possibility that the theory of two-stage carcinogenesis can be applied to neurogenic carcinogenesis, we analyzed the promoting effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the in vitro malignant transformation of fetal rat brain cells exposed in utero to ethylnitrosourea (ENU). Rat brain cells were transferred to a cultured system at 72 h after a single pulse of ENU (50 mg/kg body weight) to pregnant SD-JCL rats on the 18th day of gestation. The positive findings of glial fibrillary acidic protein and S-100 protein in primary cultured cells by the analysis of immunohistochemistry revealed the neuroglial origin of transformed cells. These cells were divided into 12 groups and were treated twice per week with or without TPA at concentrations from 0.1 to 50.0 ng/ml. From the results of cellular morphology, Concanavalin A agglutinability, colony forming capacity in semisolid soft agar, and tumorigenicity in vivo, malignant transformation of fetal rat brain cells appeared earlier in the ENU group treated with TPA than in the untreated ENU group. On the basis of these observations, it is suggested that TPA might be effective as a tumor promoter on ENU-induced neurogenic carcinogenesis.  相似文献   
9.
BACKGROUND: Although selective serotonin reuptake inhibitors (SSRIs) are the mainstay of pharmacological treatment for obsessive-compulsive disorder (OCD), some OCD patients do not show improvement. Sometimes, the addition of a low-dose atypical antipsychotic, such as risperidone, or olanzapine, to ongoing SSRI treatment has been shown to be effective. However, there are patients who still show no response after trials with this augmentation therapy. In the present study, we examined the clinical features of OCD patients who showed different responses to pharmacological treatment. SUBJECTS AND METHOD: Fifty OCD patients were divided into three groups according to their pharmacological responses: responders to SSRI (group A: n= 25), responders to SSRI with an atypical antipsychotic (group B: n= 15), and non-responders to both SSRI and SSRI with an atypical antipsychotic (group C: n= 10). We examined the clinical features such as age, sex, age of onset, duration of illness, types of obsessive-compulsive symptoms, severity, improvement after treatment, insight into disease, depression, comorbidity, involving family members in compulsive or ritualistic behavior, and the level of social adaptation of each OCD group. RESULTS: Twenty five patients showed a good response to SSRI monotherapy, 15 showed a response to antipsychotic augmentation, and 10 were non-responders to both SSRI and SSRI with an atypical antipsychotic. Significantly lower insight levels were observed only in group B and higher depressive levels in group C. OCD patients who were refractory to SSRI monotherapy showed comorbidity at a significantly higher frequency. OCD patients in group A showed significantly greater improvement, and group B showed inferior social adaptation after treatment. There were no significant differences in age, sex, age of onset, duration of illness, severity, involving family members in compulsive or ritualistic behavior, and social adaptation before treatment in the three OCD groups. CONCLUSION: There were differences in the clinical features of OCD patients who showed different responses to pharmacological treatment. Our results suggest that OCD is clinically and biologically heterogeneous. It may be important to divide OCD patients into subgroups for future studies.  相似文献   
10.
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