全文获取类型
收费全文 | 1754篇 |
免费 | 107篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 102篇 |
妇产科学 | 32篇 |
基础医学 | 243篇 |
口腔科学 | 19篇 |
临床医学 | 133篇 |
内科学 | 300篇 |
皮肤病学 | 30篇 |
神经病学 | 128篇 |
特种医学 | 33篇 |
外科学 | 254篇 |
综合类 | 28篇 |
预防医学 | 94篇 |
眼科学 | 66篇 |
药学 | 228篇 |
中国医学 | 19篇 |
肿瘤学 | 142篇 |
出版年
2023年 | 13篇 |
2022年 | 28篇 |
2021年 | 57篇 |
2020年 | 25篇 |
2019年 | 28篇 |
2018年 | 42篇 |
2017年 | 25篇 |
2016年 | 35篇 |
2015年 | 46篇 |
2014年 | 45篇 |
2013年 | 99篇 |
2012年 | 132篇 |
2011年 | 122篇 |
2010年 | 95篇 |
2009年 | 73篇 |
2008年 | 136篇 |
2007年 | 109篇 |
2006年 | 103篇 |
2005年 | 112篇 |
2004年 | 87篇 |
2003年 | 94篇 |
2002年 | 77篇 |
2001年 | 19篇 |
2000年 | 22篇 |
1999年 | 22篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 13篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1971年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有1867条查询结果,搜索用时 31 毫秒
31.
Vijaya Kumar Muppiri Syed Nasheed Ali Kumar Ravinuthala Venkat Krishna Lanka Satya Rama 《Indian Journal of Thoracic and Cardiovascular Surgery》2011,27(4):161-164
Introduction
Combined aortic and mitral valve disease is usually of rheumatic origin. In these patients we often encounter problem of small valve annuli particularly with aortic annulus. It is still debated whether a small prosthesis should be used or aortic root should be enlarged to prevent Patient Prosthesis Mismatch (PPM). This study was undertaken to review our strategy and feasibility of Aortic Root Enlargement (ARE) in patient undergo Double Valve Replacement (DVR) to avoid mismatch without increase in cost of treatment, morbidity or mortality. 相似文献32.
Immunization among the high risk groups, including the elderly, remains unacceptably low for pneumococcal and influenza vaccines.
This study determined the factors which influence pneumococcal vaccine compliance in the aged. A questionnaire developed for
this study was mailed to all 300 veterans in west central Florida who were 85 years or older and were eligible for ambulant
medical care at the James A. Haley Veterans Hospital, Tampa, Florida. They were asked regarding circumstances which influenced
their decision for or against accepting pneumococcal vaccine. Ninety-two persons responded in self-addressed stamped envelopes
and data were analyzed six months following mailing date. The single most important factor for not accepting vaccination was
lack of information and unawareness that the immunization was necessary (81%). Fear of “shots” and side effects was the next
most important reason for not taking the vaccine (15%). Lack of transportation to the doctor’s office prevented 12% of the
subjects. Some subjects also did not have an interest in prophylactic immunization (8%).
These data suggest that the lack of awareness, knowledge and information about pneumococcal immunization plays major roles
in its poor acceptance among the elderly. Health education measures should improve vaccine compliance in this population who
suffer from higher death rates and complications from pneumonia. 相似文献
33.
Kiranmai Gelli Mahendar Porika Rama Narsimha Reddy Anreddy 《Environmental toxicology》2015,30(3):308-314
In this study, we have evaluated the pulmonary toxicity of MgO nanoparticles (MgO NPs) in rats following their exposure. NPs in phosphate buffered saline + 1% Tween 80 were exposed via intratracheal instillation at a doses of 1 mg/kg or 5 mg/kg into rat lungs and evaluated for various tissue damage markers like alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid and histopathology of lungs at 1, 7, and 30 days of post‐exposure intervals. A dose‐dependant increase in ALP and LDH activity was observed in BAL fluids of rat lungs than sham control at all post‐exposure periods (P <0.05), and a dose‐dependant infiltration of interstitial lymphocytes, peribronchiolar lymphocytic infiltration, and dilated and/or congested vessels at 1 day post‐exposure period, worsened at 1 week period, and were reduced at 1 month at histology, indicating the pulmonary toxicity of MgO NPs. In conclusion, MgO NPs exposure produced a dose‐dependent pulmonary toxicity in rats and was comparable with that of Quartz particles. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 308–314, 2015. 相似文献
34.
Brian Miller MD Rama Vunnam MD Olurotimi Mesubi MD Mark F. Smith PhD Wengen Chen MD Jagat Bandhu Mahat MD Soren M. Bentzen D.M.Sc PhD Vincent See MD Alejandro Restrepo MD Stephen Shorofsky MD PhD Vasken Dilsizian MD Timm-Michael L. Dickfeld MD PhD 《Journal of cardiovascular electrophysiology》2021,32(8):2238-2245
35.
Asthma represents one of the most common chronic medical conditions affecting children. Although complications of asthma are rare, they deserve consideration when treating children with asthma. The aim of this study was report our experience with an 11-year-old boy with asthma that was complicated by bronchiectasis and to review our hospital's 10-year experience with bronchiectasis. We observed clinical and laboratory findings in a young boy with chronic asthma who developed bronchiectasis, reviewed medical records of 53 children with bronchiectasis followed at a university children's hospital to identify etiologies of bronchiectasis, and reviewed articles in the medical literature. Complications of asthma along with their diagnosis, pathogenesis, and treatment options are outlined in the discussion section. We describe the case of an 11-year-old boy with chronic asthma who did not respond to conventional asthma management and was found to have bronchiectasis. A detailed workup undertaken to identify the cause was negative for usual etiologies of bronchiectasis. In this patient, bronchiectasis was felt to be secondary to a long-standing history of asthma. Aggressive treatment of bronchiectasis led to significant improvement of asthma. Among 53 patients admitted for bronchiectasis, only 3 cases (5.6%) of asthma were identified. Cystic fibrosis (50.9%) and infection (13.2%) were the most common etiologies identified in our hospital's experience. No clear etiology was identified in 1.8% of patients. Although rare, bronchiectasis does occur in patients with chronic asthma. It is important that complications be recognized and treated for optimal management of asthma. 相似文献
36.
Oxidative Stress in the Pathogenesis of Hepatic Encephalopathy 总被引:2,自引:0,他引:2
The pathogenesis of hepatic encephalopathy (HE) remains elusive. While it is clear that ammonia is the likely toxin and that astrocytes are the main target of its neurotoxicity, precisely how ammonia brings about cellular injury is poorly understood. Studies over the past decade have invoked the concept of oxidative stress as a pathogenetic mechanism for ammonia neurotoxicity. This review sets out the arguments in support of this concept based on evidence derived from human observations, animal studies, and cell culture investigations. The consequences and potential therapeutic implications of oxidative stress in HE are also discussed. 相似文献
37.
Smita S. Iyer Donald R. Latner Michael J. Zilliox Megan McCausland Rama S. Akondy Pablo Penaloza‐MacMaster Jeffrey Scott Hale Lilin Ye Ata‐Ur‐Rasheed Mohammed Tomoyuki Yamaguchi Shimon Sakaguchi Rama R. Amara Rafi Ahmed 《European journal of immunology》2013,43(12):3219-3232
CD4+ T follicular helper (TFH) cells are central for generation of long‐term B‐cell immunity. A defining phenotypic attribute of TFH cells is the expression of the chemokine R CXCR5, and TFH cells are typically identified by co‐expression of CXCR5 together with other markers such as PD‐1, ICOS, and Bcl‐6. Herein, we report high‐level expression of the nutrient transporter folate R 4 (FR4) on TFH cells in acute viral infection. Distinct from the expression profile of conventional TFH markers, FR4 was highly expressed by naive CD4+ T cells, was downregulated after activation and subsequently re‐expressed on TFH cells. Furthermore, FR4 expression was maintained, albeit at lower levels, on memory TFH cells. Comparative gene expression profiling of FR4hi versus FR4lo Ag‐specific CD4+ effector T cells revealed a molecular signature consistent with TFH and TH1 subsets, respectively. Interestingly, genes involved in the purine metabolic pathway, including the ecto‐enzyme CD73, were enriched in TFH cells compared with TH1 cells, and phenotypic analysis confirmed expression of CD73 on TFH cells. As there is now considerable interest in developing vaccines that would induce optimal TFH cell responses, the identification of two novel cell surface markers should be useful in characterization and identification of TFH cells following vaccination and infection. 相似文献
38.
Javier Costas Jose Javier Suárez‐Rama Noa Carrera Eduardo Paz Mario Páramo Santiago Agra Julio Brenlla Ramón Ramos‐Ríos Manuel Arrojo 《Annals of human genetics》2013,77(6):504-512
A balanced translocation affecting DISC1 cosegregates with several psychiatric disorders, including schizophrenia, in a Scottish family. DISC1 is a hub protein of a network of protein–protein interactions involved in multiple developmental pathways within the brain. Gene set‐based analysis has been proposed as an alternative to individual analysis of single nucleotide polymorphisms (SNPs) to get information from genome‐wide association studies. In this work, we tested for an overrepresentation of the DISC1 interacting proteins within the top results of our ranked list of genes based on our previous genome‐wide association study of missense SNPs in schizophrenia. Our data set consisted of 5100 common missense SNPs genotyped in 476 schizophrenic patients and 447 control subjects from Galicia, NW Spain. We used a modification of the Gene Set Enrichment Analysis adapted for SNPs, as implemented in the GenGen software. The analysis detected an overrepresentation of the DISC1 interacting proteins (permuted P‐value = 0.0158), indicative of the role of this gene set in schizophrenia risk. We identified seven leading‐edge genes, MACF1, UTRN, DST, DISC1, KIF3A, SYNE1, and AKAP9, responsible for the overrepresentation. These genes are involved in neuronal cytoskeleton organization and intracellular transport through the microtubule cytoskeleton, suggesting that these processes may be impaired in schizophrenia. 相似文献
39.
Sourav Khan Rayappan Pavul Raj Talla Venkata Rama Mohan Parasuraman Selvam 《RSC advances》2020,10(51):30406
Herein, we report a single-step synthesis, characterization, and electrochemical performance of nano-sized LiFePO4 (LFP)-embedded 3D-cubic mesoporous carbon (CSI-809) and nitrogenous carbon (MNC-859) composites. Furthermore, in order to investigate the effects of both CSI-809 and MNC-859 on the electrochemical characteristics of LFP, a systematic study was performed on the morphology and microstructure of the composites, viz., LFP/CSI-809 and LFP/MNC-859, using XRD, FE-SEM, FT-Raman, and BET surface area analyses. Among these composites, LFP/MNC-859 exhibited better electrochemical performance with higher specific capacity and rate capability as compared to those of LFP/CSI-809. In addition, even after 100 cycles, LFP/MNC-859 retained 97% of its initial discharge capacity at 1C rate. The enhanced electrochemical performance of the nano-sized LFP-embedded MNC-859 can be attributed to the conductive nitrogenous carbon and mesoporosity, which facilitate electrolyte diffusion, and improved conductivity of the advanced LFP-nitrogenous porous carbon matrix.Nano-sized LiFePO4-embedded nitrogenous ordered mesoporous carbon composite cathode facilitate electronic conductivity and significantly enhances Li-ion diffusion and retains 97% of the initial discharge capacity at 1C rate even after 100 cycles. 相似文献
40.
In this study, we have reported selective synthesis of bismuth molybdate (γ-Bi2M2O6) nanoparticles (NPs) under different pH conditions for photocatalytic degradation of methylene blue (MB), reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and antimicrobial activities. The synthesis of pure phase γ-Bi2M2O6 at pH = 3 was confirmed by X-ray diffraction (XRD) and Raman analysis. A single hexagonal morphology was obtained at pH = 3 which shows the formation of the pure phase γ-Bi2M2O6 NPs. The mixed morphologies (hexagonal and spherical) were observed at different pH values other than pH = 3. The bandgap energy of all the synthesized Bi2M2O6 NPs is found in the visible region (2.48–2.59 eV). The photocatalytic activity of bismuth molybdate (BM) NPs was examined by the degradation of MB under visible light irradiation. Results show that 95.44% degradation efficiency was achieved by pure γ-Bi2M2O6 NPs compared to mixed phases (γ-Bi2M2O6, α-Bi2M2O6 and β-Bi2M2O6) synthesized at pH = 1.5 and 5. Moreover, the degradation efficiency of γ-Bi2M2O6 was enhanced to 98.89% by the addition of H2O2. The effective catalytic activity of γ-Bi2M2O6 was observed during the reduction of 4-NP to 4-AP by NaBH4. Potential antibacterial and antifungal activity of γ-Bi2M2O6 was observed, which gives a basis for further study in the development of antibiotics.In this study, we have reported selective synthesis of γ-Bi2M2O6 NPs under different pH conditions for photocatalytic degradation of methylene blue (MB), reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and antimicrobial activities. 相似文献