全文获取类型
收费全文 | 2591篇 |
免费 | 170篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 143篇 |
妇产科学 | 33篇 |
基础医学 | 272篇 |
口腔科学 | 239篇 |
临床医学 | 312篇 |
内科学 | 575篇 |
皮肤病学 | 40篇 |
神经病学 | 162篇 |
特种医学 | 263篇 |
外科学 | 221篇 |
综合类 | 42篇 |
预防医学 | 215篇 |
眼科学 | 37篇 |
药学 | 150篇 |
1篇 | |
中国医学 | 4篇 |
肿瘤学 | 45篇 |
出版年
2022年 | 11篇 |
2021年 | 34篇 |
2020年 | 31篇 |
2019年 | 35篇 |
2018年 | 55篇 |
2017年 | 57篇 |
2016年 | 60篇 |
2015年 | 73篇 |
2014年 | 70篇 |
2013年 | 95篇 |
2012年 | 137篇 |
2011年 | 152篇 |
2010年 | 88篇 |
2009年 | 88篇 |
2008年 | 116篇 |
2007年 | 103篇 |
2006年 | 118篇 |
2005年 | 107篇 |
2004年 | 83篇 |
2003年 | 72篇 |
2002年 | 81篇 |
2001年 | 49篇 |
2000年 | 50篇 |
1999年 | 42篇 |
1998年 | 94篇 |
1997年 | 92篇 |
1996年 | 95篇 |
1995年 | 63篇 |
1994年 | 55篇 |
1993年 | 45篇 |
1992年 | 34篇 |
1991年 | 44篇 |
1990年 | 21篇 |
1989年 | 41篇 |
1988年 | 38篇 |
1987年 | 44篇 |
1986年 | 26篇 |
1985年 | 40篇 |
1984年 | 28篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 13篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1970年 | 12篇 |
1967年 | 7篇 |
排序方式: 共有2772条查询结果,搜索用时 296 毫秒
81.
82.
83.
S Mukherjee K Abhinav PJ Revington 《Annals of the Royal College of Surgeons of England》2015,97(1):66-72
IntroductionThe aim of this study was to determine the incidence and patterns of cervical spine injury (CSI) associated with maxillofacial fractures at a UK trauma centre.MethodsA retrospective analysis was conducted of 714 maxillofacial fracture patients presenting to a single trauma centre between 2006 and 2012.ResultsOf the 714 maxillofacial fracture patients, 2.2% had associated CSI including a fracture, cord contusion or disc herniation. In comparison, 1.0% of patients without maxillofacial trauma sustained a CSI (odds ratio: 2.2, p=0.01). The majority (88%) of CSI cases of were caused by a road traffic accident (RTA) with the remainder due to falls. While 8.8% of RTA related maxillofacial trauma patients sustained a CSI, only 2.0% of fall related patients did (p=0.03, not significant). Most (70%) of the CSIs occurred at C1/C2 or C6/C7 levels. Overall, 455, 220 and 39 patients suffered non-mandibular, isolated mandibular and mixed mandibular/non-mandibular fractures respectively. Their respective incidences of CSI were 1.5%, 1.8% and 12.8% (p=0.005, significant). Twelve patients with concomitant CSI had their maxillofacial fractures treated within twenty-four hours and all were treated within four days.ConclusionsThe presence of maxillofacial trauma mandates exclusion and prompt management of cervical spine injury, particularly in RTA and trauma cases involving combined facial fracture patterns. This approach will facilitate management of maxillofacial fractures within an optimum time period. 相似文献
84.
Tiago Castro e Couto Mayra Yara Martins Brancaglion António Alvim-Soares Lafaiete Moreira Frederico Duarte Garcia Rodrigo Nicolato Regina Amélia Lopes P Aguiar Henrique Vitor Leite Humberto Corrêa 《World Journal of Psychiatry》2015,5(1):103-111
Postpartum depression is one of the most prevalent psychopathologies. Its prevalence is estimated to be between 10% and 15%. Despite its multifactorial etiology, it is known that genetics play an important role in the genesis of this disorder. This paper reviews epidemiological evidence supporting the role of genetics in postpartum depression (PPD). The main objectives of this review are to determine which genes and polymorphisms are associated with PPD and discuss how this association may occur. In addition, this paper explores whether these genes are somehow related to or even the same as those linked to Major Depression (MD). To identify gaps in the current knowledge that require investigation, a systematic review was conducted in the electronic databases PubMed, LILACS and SciELO using the index terms “postpartum depression” and “genetics”. Literature searches for articles in peer-reviewed journals were made until April 2014. PPD was indexed 56 times with genetics. The inclusion criteria were articles in Portuguese, Spanish or English that were available by institutional means or sent by authors upon request; this search resulted in 20 papers. Genes and polymorphisms traditionally related to MD, which are those involved in the serotonin, catecholamine, brain-derived neurotrophic factor and tryptophan metabolism, have been the most studied, and some have been related to PPD. The results are conflicting and some depend on epigenetics, which makes the data incipient. Further studies are required to determine the genes that are involved in PPD and establish the nature of the relationship between these genes and PPD. 相似文献
85.
Clinical observations in patients with X-linked hypophosphataemic rickets, that bone changes can be corrected during puberty, suggest that androgen can participate actively in the process of bone mineralization. In the present study we investigated the role of testosterone on the bone mineralization of male rats placed on a low phosphorus and vitamin D diet and kept in complete darkness after weaning. After 15 days the animals presented hypophosphataemia, rickets and osteomalacia, as assessed by histomorphometry of the tibia and seventh caudal vertebra calcification fronts respectively. Testosterone propionate administration for five days, while the animals were kept on the same rachitogenic diet, induced an improvement in the bone mineralization process of the hypophosphataemic rat independently of serum phosphate levels. Testosterone-treated rats were cured of rickets but not of osteomalacia, despite the reduction in osteoid seam area. 相似文献
86.
Alloimmunization to platelets in heavily transfused patients with sickle cell disease 总被引:2,自引:0,他引:2
Bone marrow transplantation (BMT) is now an option for some patients with sickle cell disease (SCD). Many SCD patients are multiply transfused with red blood cells (RBCs), and may be immunized to alloantigens other than erythrocyte antigens. Because platelet refractoriness is a significant complication during BMT, we wished to determine the prevalence of alloimmunization to platelets in transfused SCD patients. Sera collected from 47 transfused and 14 untransfused SCD patients were screened for HLA and platelet-specific antibodies. Transfusion and RBC antibody histories were reviewed. A subset of the patients were rescreened 1 year later. Eighty-five percent of patients with at least 50 RBC transfusions (22 of 26), 48% of patients with less than 50 transfusions (10 of 21), and none of 14 untransfused patients demonstrated platelet alloimmunization (P < .05). Platelet alloimmunization was more prevalent than RBC alloimmunization (20% to 30%). Half of the platelet reactivity was chloroquine-elutable. Eighteen of 22 patients (82%) on chronic RBC transfusion remained platelet-alloimmunized 11 to 22 months after initial testing. In summary, 85% of heavily transfused SCD patients are alloimmunized to HLA and/or platelet-specific antigens. These patients may be refractory to platelet transfusion, a condition that would increase their risk during BMT. Leukodepletion in the transfusion support of SCD patients should be considered to prevent platelet alloimmunization. 相似文献
87.
We have previously reported that lithium chloride (LiCl) stimulates the production of granulocyte-macrophage colony-forming cells (GM-CFC), pluripotent stem cells (CFU-S), and differentiated granulocytes, macrophages and megakaryocytes in murine Dexter marrow cultures and that this effect appears to be mediated indirectly by a radioresistant adherent marrow cell. In this study we have established that exposure of murine Dexter cultures to LiCl (4 mEq/L) causes an increase of colony-forming cell megakaryocytes (CFU-meg) over 1 to 6 weeks of culture in both supernatant (188% to 611%) and stromal phases (123% to 246%). Moreover, we have shown that lithium treatment of either irradiated (1,100 rad) or unirradiated stromal cells increased production of activities stimulating formation of megakaryocyte, granulocyte, macrophage, and mixed lineage colonies and proliferation of the factor-dependent cell line, FDC-P1. This FDC-P1 stimulatory activity was completely blocked by an antibody to purified recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF). The baseline or lithium-induced--stromal-derived bone marrow colony stimulating activity was partially blocked by the antibody to rGM-CSF and by an antibody to purified colony stimulating factor I (CSF-1); the two antibodies combined resulted in greater than 90% inhibition of the lithium-induced marrow stimulatory activity. In addition, radioimmunoassay (RIA) showed that although CSF-1 was detectable in supernatants of these cultures, exposure to lithium did not increase CSF-1 levels. These data indicate that Dexter stromal cells produce CSF- 1 and GM-CSF and that lithium appears to exert its stimulatory effects on in vitro myelopoiesis by inducing production of GM-CSF. 相似文献
88.
Immunologic status of hemophilia patients treated with cryoprecipitate or lyophilized concentrate 总被引:1,自引:0,他引:1
We evaluated 37 patients with moderate or severe hemophilia A and six patients with severe factor IX deficiency for clinical or laboratory evidence of immune abnormalities. Patients were assigned to one of four groups according to the type of clotting factor replacement. Twenty patients had received only cryoprecipitate during the two years preceding the evaluation (group I); 11 additional patients were treated predominantly with cryoprecipitate but had also received up to nine bottles of factor VIII concentrate (group II); six patients received factor VIII concentrate (group III); six patients received factor IX concentrate (group IV). There was no clinical or laboratory evidence of immunodeficiency among the 43 patients. The mean absolute number of Th cells was normal in all patient groups, but the mean absolute number of Ts cells was increased compared with controls, both in patients treated with cryoprecipitate and in patients treated with factor VIII or factor IX concentrate. There was no correlation between the Th/Ts ratio and patient age, alanine aminotransferase level, hepatitis serology, in vitro lymphocyte function, or amount of clotting factor administered. Our observations demonstrate that the volunteer or commercial origin of clotting factor replacement cannot fully explain the alterations in lymphocyte subset distribution previously described in patients with hemophilia A. 相似文献
89.
90.
Lívia L. Corrêa Leonardo Vieira Neto Giovanna A. Balarini Lima Rafael Gabrich Luiz Carlos D. de Miranda M?nica R. Gadelha 《International braz j urol : official journal of the Brazilian Society of Urology》2015,41(1):110-115