全文获取类型
收费全文 | 4650篇 |
免费 | 331篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 96篇 |
妇产科学 | 133篇 |
基础医学 | 610篇 |
口腔科学 | 133篇 |
临床医学 | 444篇 |
内科学 | 1073篇 |
皮肤病学 | 78篇 |
神经病学 | 326篇 |
特种医学 | 116篇 |
外国民族医学 | 1篇 |
外科学 | 625篇 |
综合类 | 107篇 |
一般理论 | 3篇 |
预防医学 | 387篇 |
眼科学 | 147篇 |
药学 | 402篇 |
中国医学 | 69篇 |
肿瘤学 | 242篇 |
出版年
2024年 | 6篇 |
2023年 | 86篇 |
2022年 | 189篇 |
2021年 | 267篇 |
2020年 | 201篇 |
2019年 | 246篇 |
2018年 | 265篇 |
2017年 | 210篇 |
2016年 | 216篇 |
2015年 | 223篇 |
2014年 | 299篇 |
2013年 | 339篇 |
2012年 | 507篇 |
2011年 | 460篇 |
2010年 | 246篇 |
2009年 | 204篇 |
2008年 | 226篇 |
2007年 | 223篇 |
2006年 | 184篇 |
2005年 | 110篇 |
2004年 | 90篇 |
2003年 | 69篇 |
2002年 | 62篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 21篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有5029条查询结果,搜索用时 15 毫秒
11.
Seyed Heydar Mosavi Mirak Seyedmehdi Sharifian Fatemeh Esmaeili Khalil Saraei Neda Asasian-Kolur Bahram Haddadi Christian Jordan Michael Harasek 《Materials》2022,15(13)
Titanium-pillared clay (Ti-PILC), as one of the most suitable types of porous adsorbents/(photo)catalysts, was prepared from a local type of Iranian clay and titanium isopropoxide. The production process was optimized by changing three operating parameters, including the clay suspension concentration (in the range of 0.5–10% w/v), the H+/Ti ratio (2–8 mol/mol), and the calcination temperature (300–700 °C). The largest specific surface area for the Ti-PILC was about 164 m2/g under the clay suspension of 0.5% w/v, H+/Ti = 6, with a surface area 273% larger than that of the raw clay. The surface areas obtained from more concentrated clay suspensions were, however, comparable (159 m2/g for 3% w/v clay and H+/Ti = 4). An increase in the calcination temperature has a negative effect on the porous texture of Ti-PILC, but based on modeling with artificial neural networks, its contribution was only 7%. Clay suspension and H+/Ti ratio play a role of 56 and 37% of the specific surface area. The presence of rutile phase, and in some cases anatase phase of TiO2 crystals was detected. FTIR and SEM investigations of Ti-PILCs produced under different operating parameters were analyzed. 相似文献
12.
13.
14.
15.
IntroductionSexual fear is a known cause for avoidance of intercourse, especially in patients with chronic conditions.AimGiven the significant impact of fear of intercourse on the quality of life, we herein report our pilot results regarding the differences in the demographic, clinical, marital, and psychological characteristics of coronary artery disease (CAD) patients with and without sexual fear.MethodsIn this cross-sectional study conducted in Baqyiatallah Hospital, Tehran, Iran, in 2006, 87 married CAD patients were assessed for the presence of sexual fear. Subjects with and without sexual fear were compared for demographic and clinical data as well as for Hospital Anxiety and Depression Scale (HADS) and Revised-Dyadic Adjustment Scale (R-DAS) scores.Main Outcome MeasureDemographic and clinical data, sexual fear (Relationship and Sexuality Scale), symptoms of anxiety and depression (HADS), and marital relation quality (R-DAS).ResultsTwenty-nine subjects were reported to have some degrees of fear of sexual intercourse and a lower frequency of sexual intercourse. Age, socioeconomic status, education level, tobacco smoking, and history of myocardial infarction were significantly different between those with and the ones without sexual fear. Body mass index, extent of coronary involvement, chronic obstructive pulmonary disease, hypertension, stroke, hyperlipidemia, history of diabetes, and the use of beta-blockers were not statistically different in the two groups. The subjects with sexual fear reported higher HADS depressive and R-DAS scores but not higher HADS anxiety scores.ConclusionAmong different nonmodifiable and modifiable correlates of fear of sexual intercourse in CAD patients, marital relationship and depressive symptoms should be highlighted in future interventional studies with the aim of allaying such fears. Kazemi-Saleh D, Pishgou B, Assari S, and Tavallaii SA. Fear of sexual intercourse in patients with coronary artery disease: A pilot study of associated morbidity. 相似文献
16.
Yaser Jenab Parham Ghafouri Kaveh Hosseini Shapour Shirani Mahmood Shirzad 《Clinical Case Reports》2022,10(6)
Bilateral proximal deep vein thrombosis (DVT) in the lower extremities of young patients should raise suspicion over pro‐thrombotic conditions and venous anatomical abnormalities, even in the presence of other precipitating factors, such as viral infection. The authors present a 33‐year‐old man with bilateral DVT and absence of inferior vena cava (AIVC), who also had concurrent COVID‐19, and discuss the management of this patient. 相似文献
17.
Mahdi Asghari Ozma Amin Abbasi Sousan Akrami Masoud Lahouty Nayyer Shahbazi Khudaverdi Ganbarov Pasquale Pagliano Sahar Sabahi ükran Kse Mehdi Yousefi Sounkalo Dao Mohammad Asgharzadeh Hedayat Hosseini Hossein Samadi Kafil 《Le infezioni in medicina : rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive》2022,30(2):180
18.
H. Ghobadian Diali H. Hosseini M. H. Fallah Mehrabadi R. Yahyaraeyat A. Ghalyanchilangeroudi 《Majallah-i ta?qīqāt-i dāmpizishkī-i īrān》2022,23(1):18
Background:Infectious bronchitis virus (IBV) causes severe economic losses worldwide. IBV has a broad tissue distribution with different viral loads in different tissues. Additionally, IBV can induce apoptosis in infected cells. Aims:The present study aimed to evaluate the role of the genetic background of chickens in viral load and the expression level of apoptotic genes in different tissues of two hybrids of commercial broiler chickens (Ross 308 and Cobb 500) challenged with IBV. Methods:Chickens at 21 days of age were nasally challenged with 200 μL of allantoic fluid containing 104 EID50/ml of Iranian variant-2-like IBV (IS/1494). The expression level of apoptotic genes (Fas, FasL, Bax, and Bcl-2) in the tracheal and renal tissues and the amount of viral load in the tracheal, renal, and cloacal swab samples were investigated two, five, and seven days after IBV infection by RT-qPCR assay. Results:The amount of viral load and apoptotic the expression level of apoptotic genes in the tracheal (two and five days after infection) and renal samples (seven days after infection) were significantly higher in the Ross challenged group than in the Cobb challenged group.Furthermore, no difference was observed in the cloaca viral load on sampling days. Conclusion:To our knowledge, this is the first report that evaluated the role of the chickens’ genetic background in the amount of viral load and the expression level of apoptotic genes against IBV. Further studies are needed to investigate the pathogenic characteristics of IBV in Ross 308 and Cobb 500 chickens.Key Words: Apoptosis, Broiler chickens, Infectious bronchitis virus, Viral load 相似文献
19.
Seyed Ataollah Naghavi Haoyu Wang Swastina Nath Varma Maryam Tamaddon Arsalan Marghoub Rex Galbraith Jane Galbraith Mehran Moazen Jia Hua Wei Xu Chaozong Liu 《Materials》2022,15(14)
Additively manufactured Ti scaffolds have been used for bone replacement and orthopaedic applications. In these applications, both morphological and mechanical properties are important for their in vivo performance. Additively manufactured Ti6Al4V triply periodic minimal surface (TPMS) scaffolds with diamond and gyroid structures are known to have high stiffness and high osseointegration properties, respectively. However, morphological deviations between the as-designed and as-built types of these scaffolds have not been studied before. In this study, the morphological and mechanical properties of diamond and gyroid scaffolds at macro and microscales were examined. The results demonstrated that the mean printed strut thickness was greater than the designed target value. For diamond scaffolds, the deviation increased from 7.5 μm (2.5% excess) for vertical struts to 105.4 μm (35.1% excess) for horizontal struts. For the gyroid design, the corresponding deviations were larger, ranging from 12.6 μm (4.2% excess) to 198.6 μm (66.2% excess). The mean printed pore size was less than the designed target value. For diamonds, the deviation of the mean pore size from the designed value increased from 33.1 μm (−3.0% excess) for vertical struts to 92.8 μm (−8.4% excess) for horizontal struts. The corresponding deviation for gyroids was larger, ranging from 23.8 μm (−3.0% excess) to 168.7 μm (−21.1% excess). Compressive Young’s modulus of the bulk sample, gyroid and diamond scaffolds was calculated to be 35.8 GPa, 6.81 GPa and 7.59 GPa, respectively, via the global compression method. The corresponding yield strength of the samples was measured to be 1012, 108 and 134 MPa. Average microhardness and Young’s modulus from α and β phases of Ti6Al4V from scaffold struts were calculated to be 4.1 GPa and 131 GPa, respectively. The extracted morphology and mechanical properties in this study could help understand the deviation between the as-design and as-built matrices, which could help develop a design compensation strategy before the fabrication of the scaffolds. 相似文献
20.
Teamur Aghamolaei Asiyeh Pormehr-Yabandeh Zahra Hosseini Nasibeh Roozbeh Mahdieh Arian Amin Ghanbarnezhad 《Ethiopian journal of health sciences》2022,32(4):849
BackgroundPregnancy is a major concern among women with the sickle cell disease (SCD), and it is associated with increased adverse outcomes. The aim of the present meta-analysis is to report the fetomaternal outcomes in different sickle cell genotypes.MethodsIn this systematic review and meta-analysis, a comprehensive search of databases and search engines such as PubMed, Scopus, Web of Science, ProQuest, Cochrane Library, Science Direct and Google Scholar were performed. Any observational studies that had compared at least one outcome such as maternal outcomes, fetal outcomes, and morbidity between two groups of pregnant women with different types of sickle cell genotypes and pregnant women without SCD were evaluated.ResultsA total number of 9,827 pregnant women with SCD were examined. The results showed that pregnancy in SCD increased the risk of adverse outcomes for the mothers (including postpartum hemorrhage, prematurity, pregnancy-induced hypertension, pre-eclampsia, eclampsia, cesarean section, lower segment cesareansection, maternal death), fetus (including live births, low birth weight, intrauterine growth restriction, APGAR score at 5 min <7, stillbirth, neonatal death, perinatal mortality, acute fetal distress, intrauterine fetal death) and morbidity among the SCD(severe anemia, urinary tract infection, blood transfusion, painful crisis, acute chest syndrome, vaso-occlusive crises).ConclusionAccording to the results of this meta-analysis, pregnancy in the SCD is associated with an increased risk of maternal outcomes, fetal outcomes, and morbidity among SCD patients with different genotypes. Pregnancy in sickle cell hemoglobinopathies needs careful multidisciplinary management and cautious caring so as to decrease maternal and fetal morbidity and mortality. 相似文献