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   2866篇
  免费   134篇
  国内免费   13篇
耳鼻咽喉   9篇
儿科学   50篇
妇产科学   51篇
基础医学   469篇
口腔科学   105篇
临床医学   208篇
内科学   681篇
皮肤病学   48篇
神经病学   198篇
特种医学   68篇
外科学   507篇
综合类   15篇
预防医学   171篇
眼科学   30篇
药学   190篇
中国医学   3篇
肿瘤学   210篇
  2023年   22篇
  2022年   47篇
  2021年   88篇
  2020年   49篇
  2019年   84篇
  2018年   88篇
  2017年   85篇
  2016年   73篇
  2015年   79篇
  2014年   95篇
  2013年   134篇
  2012年   225篇
  2011年   223篇
  2010年   146篇
  2009年   128篇
  2008年   199篇
  2007年   197篇
  2006年   164篇
  2005年   169篇
  2004年   164篇
  2003年   155篇
  2002年   132篇
  2001年   21篇
  2000年   18篇
  1999年   17篇
  1998年   23篇
  1997年   23篇
  1996年   15篇
  1995年   8篇
  1994年   17篇
  1993年   15篇
  1992年   8篇
  1991年   6篇
  1990年   8篇
  1989年   8篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   7篇
  1984年   6篇
  1983年   4篇
  1982年   5篇
  1976年   3篇
  1971年   3篇
  1968年   2篇
  1962年   2篇
  1939年   4篇
  1937年   2篇
  1933年   2篇
  1932年   2篇
排序方式: 共有3013条查询结果,搜索用时 15 毫秒
81.
ABSTRACT

Introduction: The use of liquid biopsy on the blood from solid malignancies provides a convenient way of detecting actionable mutations, monitoring treatment response, detecting early recurrence and prognosticating outcomes. The aim of this review is to discuss the current status and future direction of serum biomarkers in the clinical management of urinary bladder cancer.

Areas covered: This review provides an overview of blood liquid biopsy and bladder cancer using methods of circulating tumors cells, circulating RNA, serum metabolites and cell-free DNA. Recent clinical studies and advances in methodology are emphasized. We performed a literature search using PMC/PubMed with keywords including ‘liquid biopsy’, ‘circulating tumor DNA’, ‘cell-free DNA’, ‘biomarkers’, ‘bladder cancer’ ‘precision medicine’. Additional articles were obtained from the cited references of key articles. An emphasis was placed on recent studies published since 2018.

Expert opinion: Liquid biopsies represent a potential biomarker using cell-free DNA, metabolomic profiles of altered cellular metabolism, circulating cancer cells and RNA. Despite displaying tremendous clinical promise, the current status of the blood liquid biopsies has not reached fruition. However, future investigations should lead the evolution of liquid biomarker into clinical utility for the management of bladder cancer.  相似文献   
82.
83.
The cytologic features of 46 lymphoproliferative ophthalmic lesions were evaluated using the “squash” technique and/or touch imprints at the time of frozen section. Of the 46 lesions, 33 were located in the orbit, 12 in the conjunctiva, and one in the eyelid. Fifteen cases were benign (reactive) hyperplasias, and 31 were diagnosed as malignant lymphoproliferative tumors. The cytologic features of the reactive group included a polymorphic lymphoid population intermixed with scattered tingible body macrophages. Within the malignant category, there were 28 malignant lymphomas. All 28 cases were diagnosed as non-Hodgkin's lymphomas. Cytologically, the malignant group consisted of a monomorphic population of atypical lymphoid cells. Of the 31 malignant lymphoid lesions, 58% (18 tumors) were small lymphocytic proliferations. The remaining 13 tumors were classified as follows: mixed small/large cell or pure large cell lymphomas (nine), plasmacytoma (three), and Burkitt's lymphoma (one). Final classification using the Working Formulation was made after evaluating the cytologic preparations and surgical material. In selected cases, the monoclonal nature of the malignant lymphoproliferative lesions was confirmed by flow cytometry and/or immunocytochemistry. Cytologic preparations of the fresh specimens preserve the morphologic details of the tumor cells, which is especially important when evaluating lymphoid lesions. Additionally, multiple smears can be prepared simultaneously for ancillary studies such as immunocytochemistry. Of our 46 lymphoproliferative lesions, two-thirds were diagnosed as malignant lymphomas. Based on the morphologic and immunophenotypic findings, all the malignant lymphomas were B-cell tumors, 50% of which were low grade using the Working Formulation. Diagn Cytopathol 1996;15:241–245 © 1996 Wiley-Liss, Inc.  相似文献   
84.
Journal of Neurology - Trans-active response DNA-binding protein of 43 kDa (TDP-43) can be detected in up to 63% of autopsy-confirmed Lewy body disease (LBD) cases. It is unclear whether...  相似文献   
85.
86.
The metabolic syndrome includes changes in blood glucose levels, arterial hypertension, triglycerides, dyslipidemia and central obesity. Countless reports have described the correlation between the metabolic syndrome and cognitive impairment. However, only a few reports have assessed cognitive impairment associated with the metabolic syndrome in animals of both sexes. For this purpose, Sprague‐Dawley male and female rats were fed either with a hypercaloric diet as model of the metabolic syndrome or with a standard chow diet as controls. Subsequently, spatial learning and memory (Morris water maze) as well as short‐ and long‐term memory (passive avoidance task) were evaluated. Body weight, blood pressure, triglycerides, and total cholesterol significantly increased (F(1, 36) = 94.89, p < .001) in rats fed with hypercaloric diet compared to control rats. Furthermore, cognitive impairment was observed in spatial learning and spatial memory on male rats but not on female rats fed with hypercaloric diet. In addition, a long‐term memory impairment was observed in both groups fed with hypercaloric diet in comparison to their respective control group (F(1, 32) = 10.61, p = .0027). Immunohistochemistry results showed no changes in the number of positive cells for NeuN, GFAP and Ox‐42. In males fed with a hypercaloric diet, a decrease in testosterone levels was observed, whereas estradiol levels decreased in females when compared with their respective control group (p < .0001). In this MetS animal model, metabolic and cognitive differences were observed in males and females, which demonstrates that sex hormones play a significant role in metabolic regulation and neuroprotection related to the CA1 region of the hippocampus.  相似文献   
87.
Reading errors in patients with cerebellar vermis lesions   总被引:2,自引:0,他引:2  
Dyslexia, both developmental and acquired, has been considered the result of cerebrocortical dysfunction, affecting the temporo-parieto-occipital brain regions. However, dyslexia may involve abnormalities of the magnocellular component of the visual system, leading to binocular instability or alterations of accommodation. To test the hypothesis of cerebellar involvement in the reading process – justified by its emergent role in language and cognition – we studied 10 patients with cerebellar vermis/paravermis lesions using reading tests and we compared the results with those produced by 10 normal volunteers. The data obtained demonstrate an increased number of reading mistakes in the patient group, resulting from a possible alteration of the diffuse connection system from the cerebellum to different cerebrocortical and subcortical structures. Acquired dyslexia due to cerebellar impairment may be due to oculomotor alteration or, more subtly, to the intimate cerebellar-encephalic projections, connecting the cerebellum to the attentive and alerting processes and to the language system. We discuss the data with an overview of literature. Received: 22 May 2001, Received in revised form: 14 September 2001, Accepted: 25 September 2001  相似文献   
88.
Clinical Rheumatology - Evidence for Chagas disease reactivation (CDR) in rheumatologic patients under rheumatologic treatments (RTs) is scarce. To screen and follow-up patients with rheumatic...  相似文献   
89.

Aims of study

Despite the ethnopharmacological relevance of Helietta parvifolia A. Gray (Rutaceae) in Mexico, we found no significant pharmacological studies of this plant in the scientific literature. The aim of the present study was to establish the anti-inflammatory effect of an aqueous extract of the stem bark of Helietta parvifolia in mice.

Materials and methods

The anti-inflammatory activity of the aqueous extract of the stem bark of Helietta parvifolia was evaluated using carrageenan-induced paw oedema in mice, and the cotton pellet granuloma method.

Results

An extract dose ranging from 20 to 80 mg/kg p.o. showed a non-significant effect over the initial phase of carrageenan-induced oedema. However, it showed a significant inhibition of oedema after 3 h, which can be related to the inhibition of the release of kinin-like substances. An ID50 value of 47.4 mg/kg was obtained for the plant extract. The extract also suppressed granulomatous tissue formation during chronic inflammation. The inhibitory values were 19.2, and 22.2, corresponding to 40 and 80 mg/kg doses of extract respectively.

Conclusions

Aqueous extract showed a statistically significant anti-inflammatory effect in mice during the late phase of acute inflammation and during chronic inflammation. However, the exact mechanism(s) of anti-inflammatory effects of Helietta parvifolia observed in this study remains unclear.  相似文献   
90.
Several association studies and GWAS on melanoma skin cancer risk have reported statistically significant signals on 9p21.3 region, where MTAP gene maps. None of the associated SNPs identified in these studies lie in the coding region of the gene and the causative relation of risk alleles with melanoma predisposition has not been elucidated. MTAP has a tumor suppressor activity and epigenetic silencing has been described in melanoma cell lines. In the present study, we show that melanoma risk alleles correlate with a MTAP allele‐specific hyper‐methylation and down‐regulation of gene expression.  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