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   18598篇
  免费   1096篇
  国内免费   95篇
耳鼻咽喉   317篇
儿科学   486篇
妇产科学   315篇
基础医学   2663篇
口腔科学   1573篇
临床医学   1410篇
内科学   3900篇
皮肤病学   461篇
神经病学   1255篇
特种医学   554篇
外科学   2179篇
综合类   85篇
一般理论   3篇
预防医学   2061篇
眼科学   252篇
药学   1292篇
  1篇
中国医学   190篇
肿瘤学   792篇
  2024年   60篇
  2023年   211篇
  2022年   415篇
  2021年   742篇
  2020年   472篇
  2019年   591篇
  2018年   743篇
  2017年   519篇
  2016年   570篇
  2015年   639篇
  2014年   831篇
  2013年   1007篇
  2012年   1412篇
  2011年   1623篇
  2010年   868篇
  2009年   694篇
  2008年   1073篇
  2007年   1024篇
  2006年   884篇
  2005年   791篇
  2004年   658篇
  2003年   587篇
  2002年   478篇
  2001年   380篇
  2000年   342篇
  1999年   314篇
  1998年   138篇
  1997年   107篇
  1996年   104篇
  1995年   64篇
  1994年   72篇
  1993年   62篇
  1992年   143篇
  1991年   124篇
  1990年   89篇
  1989年   110篇
  1988年   96篇
  1987年   75篇
  1986年   85篇
  1985年   64篇
  1984年   59篇
  1983年   46篇
  1982年   29篇
  1981年   29篇
  1980年   32篇
  1979年   45篇
  1978年   29篇
  1977年   25篇
  1976年   35篇
  1969年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
BackgroundThe efficacy of ticagrelor in the long-term post–ST-segment elevation myocardial infarction (STEMI) treated with fibrinolytic therapy remains uncertain.ObjectivesThe purpose of this study was to evaluate the efficacy of ticagrelor when compared with clopidogrel in STEMI patients treated with fibrinolytic therapy.MethodsThis international, multicenter, randomized, open-label with blinded endpoint adjudication trial enrolled 3,799 patients (age <75 years) with STEMI receiving fibrinolytic therapy. Patients were randomized to ticagrelor (180-mg loading dose, 90 mg twice daily thereafter) or clopidogrel (300- to 600-mg loading dose, 75 mg daily thereafter). The key outcomes were cardiovascular mortality, myocardial infarction, or stroke, and the same composite outcome with the addition of severe recurrent ischemia, transient ischemic attack, or other arterial thrombotic events at 12 months.ResultsThe combined outcome of cardiovascular mortality, myocardial infarction, or stroke occurred in 129 of 1,913 patients (6.7%) receiving ticagrelor and in 137 of 1,886 patients (7.3%) receiving clopidogrel (hazard ratio: 0.93; 95% confidence interval: 0.73 to 1.18; p = 0.53). The composite of cardiovascular mortality, myocardial infarction, stroke, severe recurrent ischemia, transient ischemic attack, or other arterial thrombotic events occurred in 153 of 1,913 patients (8.0%) treated with ticagrelor and in 171 of 1,886 patients (9.1%) receiving clopidogrel (hazard ratio: 0.88; 95% confidence interval: 0.71 to 1.09; p = 0.25). The rates of major, fatal, and intracranial bleeding were similar between the ticagrelor and clopidogrel groups.ConclusionAmong patients age <75 years with STEMI, administration of ticagrelor after fibrinolytic therapy did not significantly reduce the frequency of cardiovascular events when compared with clopidogrel. (Ticagrelor in Patients With ST Elevation Myocardial Infarction Treated With Pharmacological Thrombolysis [TREAT]; NCT02298088)  相似文献   
3.
4.

Background

Postmenstrual and/or gestational age-corrected age (CA) is required to apply child growth standards to children born preterm (< 37 weeks gestational age). Yet, CA is rarely used in epidemiologic studies in low- and middle-income countries (LMICs), which may bias population estimates of childhood undernutrition. To evaluate the effect of accounting for GA in the application of growth standards, we used GA-specific standards at birth (INTERGROWTH-21st newborn size standards) in conjunction with CA for preterm-born children in the application of World Health Organization Child Growth Standards postnatally (referred to as ‘CA’ strategy) versus postnatal age for all children, to estimate mean length-for-age (LAZ) and weight-for-age (WAZ) z scores at 0, 3, 12, 24, and 48-months of age in the 2004 Pelotas (Brazil) Birth Cohort.

Results

At birth (n = 4066), mean LAZ was higher and the prevalence of stunting (LAZ < ?2) was lower using CA versus postnatal age (mean ± SD): ? 0.36 ± 1.19 versus ? 0.67 ± 1.32; and 8.3 versus 11.6%, respectively. Odds ratio (OR) and population attributable risk (PAR) of stunting due to preterm birth were attenuated and changed inferences using CA versus postnatal age at birth [OR, 95% confidence interval (CI): 1.32 (95% CI 0.95, 1.82) vs 14.7 (95% CI 11.7, 18.4); PAR 3.1 vs 42.9%]; differences in inferences persisted at 3-months. At 12, 24, and 48-months, preterm birth was associated with stunting, but ORs/PARs remained attenuated using CA compared to postnatal age. Findings were similar for weight-for-age z scores.

Conclusions

Population-based epidemiologic studies in LMICs in which GA is unused or unavailable may overestimate the prevalence of early childhood undernutrition and inflate the fraction of undernutrition attributable to preterm birth.
  相似文献   
5.
Introduction: Diabetes Mellitus has been considered an epidemic by the World Health Organization, with a high risk of morbidity and mortality. The treatment of this pathology consists in glycemic control, which can be done by oral hypoglycemic agents, insulin therapy, dietary guidance, regular physical activity, and psychosocial support. In addition, other adjuvant treatments are employed, such as phytotherapic, and one of the most used plants is Bauhinia forficata.

Areas covered: In the current review, patents using Bauhinia forficata for the Diabetes Mellitus treatment have been analyzed. There were 03 patents in WIPO, 01 in Espacenet, 01 in USPTO, and 02 in INPI.

Expert opinion: Patents on the adjuvant treatment of Diabetes Mellitus by Bauhinia forficata are discussed. Although there are some phytotherapy products containing this medicinal plant which has hypoglycemic effect here is still a need for the development of more products based on natural resources, for the treatment of this pathology, without side effects and with other benefits, to assist in the glycemia control in diabetic patients, and to improve their quality of life.  相似文献   

6.
Schematic illustration of the systemic delivery of macromolecules in the clinic using nanotherapeutics. After systemic administration of formulations, interaction can be with target cell surface (gold and iron oxide nanoparticles (NP)) or delivery system can be internalized. Endonuclease sensitive actives (siRNA, mRNA) are protected by encapsulation in delivery system. Target cell entry can be by interactions between targeting ligand on the surface of delivery system (surface functionalized cyclodextrin based NP) or by endocytosis (liposomes and nucleic acid coated gold NP). After endocytosis, delivery system can facilitate endosomal escape via endosome disruption. Protein expression occurs by translation of free mRNA in cytoplasm. For delivery systems with extracellular site of action, efficacy is achieved by initiating downstream signaling cascade. Cell surface ligands can be proteins or genetic material for extracellularly acting delivery systems.  相似文献   
7.
Introduction: Polymyalgia rheumatica (PMR), a common disease in individuals older than 50 in the western world, is characterized by bilateral inflammatory pain involving the shoulder girdle and less commonly the neck and pelvic girdle. The main goals of the currently available treatment are to induce remission and prevent relapse.

Areas covered: This review briefly presents the main epidemiological and clinical features of PMR and discusses in depth both its classical management as well as new therapies used in PMR.

Expert opinion: In general, patients with isolated PMR experience a rapid response (in less than seven days) to 12.5–25 mg/prednisone/day. Methotrexate is the conventional disease-modifying antirheumatic drug most commonly used for disease management, especially for relapses of the disease. However, this agent often yields a modest effect. Randomized controlled trials do not support the use of antitumor necrosis factor agents in PMR. Several case series and retrospective studies have highlighted the efficacy of the anti-interleukin-6 receptor antibody tocilizumab in PMR. However, controlled trials are needed to fully establish the efficacy of this biologic agent in PMR. The potential beneficial effect of the Janus-kinase inhibitors remains to be determined.  相似文献   

8.
The measures for leishmaniasis control include the precise diagnosis of disease. However, although several recombinant antigens have been tested with this biotechnological purpose, no effective product exists, which could detects patients with the active disease, as well as differentiates them from cured and treated patients. In this study, a conserved Leishmania hypothetical protein, which was identified in Leishmania infantum parasites, but evaluated to presents high homology in the amino acid sequences between distinct parasite species, was evaluated for the diagnosis of tegumentary and visceral leishmaniasis. In addition, PBMCs collected from treated and untreated mucosal leishmaniasis (ML) and visceral leishmaniasis (VL) patients, as well as in healthy subjects living in endemic region of disease, were in vitro stimulated, when IFN-γ, IL-4 and IL-10 levels were evaluated in the cell supernatant. Regarding the serological analyses, ELISA experiments using the recombinant protein (rLiHyL) and a human serological panel revealed high sensitivity and specificity values to detect both diseases, while control antigens showed worst results. Regarding the cellular response, results showed that rLiHyL-stimulated cells produced higher IFN-γ and lower IL-4 and IL-10 levels in the supernatants. Also, the anti-protein antibody production was evaluated in these patients, and data showed higher IgG2 and lower IgG1 levels found in the treated patients and healthy controls, demonstrating the stimulation of a Th1-type response induced by the rLiHyL protein. In conclusion, this hypothetical protein can be considered as antigenic in TL and VL, as well as a vaccine candidate to be tested in future studies to protect against disease.  相似文献   
9.
Infection with human papillomavirus (HPV) is the main cause of cervical cancer. Viral persistence is considered the main risk factor for neoplastic progression and evidence suggests that regulatory T cells (Treg) play an important role in the failure of viral elimination. The aim of this study was to detect phenotypic markers of Treg and cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β, in the cervical microenvironment of HPV-infected patients. One hundred and one samples of uterine cervix embedded in paraffin were analyzed. We used immunohistochemistry to examine the coexpression of the CD25/FOXP3 and CD4/TGF-β markers, and the expression of GITR and IL-10 in cells present in the cervical stroma. We detected a microenvironment composed of high proportions of CD25+FOXP3+, CD4+TGFβ+, IL-10+, and GITR+ cells in samples with high viral loads and severe lesions of HPV-infected patients. The abundance of these markers, indicative of the presence of Treg cells and immunosuppressive cytokines, was significantly associated with severe lesions and elevated viral loads in the examined samples. These results suggest that Treg cells may be involved in maintaining a microenvironment favorable for viral persistence and neoplastic progression. Our findings support those of previous studies that suggested that these markers could be used to predict HPV persistence and neoplastic progression, and as potential targets for immune response modulation.  相似文献   
10.
Parasitology Research - It is known that premature elimination of non-parasitized RBCs (nRBCs) plays an important role in the pathogenesis of malarial anemia, in which suicidal death process...  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