全文获取类型
收费全文 | 3449篇 |
免费 | 223篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 76篇 |
妇产科学 | 45篇 |
基础医学 | 480篇 |
口腔科学 | 280篇 |
临床医学 | 324篇 |
内科学 | 694篇 |
皮肤病学 | 72篇 |
神经病学 | 220篇 |
特种医学 | 268篇 |
外科学 | 307篇 |
综合类 | 32篇 |
预防医学 | 437篇 |
眼科学 | 60篇 |
药学 | 282篇 |
中国医学 | 34篇 |
肿瘤学 | 95篇 |
出版年
2024年 | 5篇 |
2023年 | 43篇 |
2022年 | 51篇 |
2021年 | 125篇 |
2020年 | 101篇 |
2019年 | 101篇 |
2018年 | 146篇 |
2017年 | 74篇 |
2016年 | 93篇 |
2015年 | 127篇 |
2014年 | 151篇 |
2013年 | 163篇 |
2012年 | 218篇 |
2011年 | 272篇 |
2010年 | 148篇 |
2009年 | 116篇 |
2008年 | 182篇 |
2007年 | 190篇 |
2006年 | 146篇 |
2005年 | 123篇 |
2004年 | 103篇 |
2003年 | 86篇 |
2002年 | 84篇 |
2001年 | 75篇 |
2000年 | 38篇 |
1999年 | 42篇 |
1998年 | 62篇 |
1997年 | 42篇 |
1996年 | 62篇 |
1995年 | 49篇 |
1994年 | 48篇 |
1993年 | 51篇 |
1992年 | 16篇 |
1991年 | 23篇 |
1990年 | 29篇 |
1989年 | 36篇 |
1988年 | 38篇 |
1987年 | 38篇 |
1986年 | 31篇 |
1985年 | 41篇 |
1984年 | 20篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 23篇 |
1980年 | 20篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1977年 | 19篇 |
1976年 | 11篇 |
1975年 | 12篇 |
排序方式: 共有3738条查询结果,搜索用时 31 毫秒
101.
102.
Luciana Carvalho Moura Priscilla Caroliny de Oliveira Juliana Guareschi dos Santos Heloisa Barboza Paglione Jose Maria do Nascimento Neto Roberta Cristina Cardoso dos Santos Marli Cristina de Oliveira Marcos André Ramos Carneiro Felipe Alves Moreira Dayana Aparecida Martins Correa Calado Renata Fabiana Leite Bartira de Aguiar Roza Paolo Rogerio de Oliveira Salvalaggio Ana Cristina Carvalho de Matos 《Clinical transplantation》2015,29(12):1047-1053
103.
Erythropoietin production in a primary culture of human renal carcinoma cells maintained in nude mice 总被引:4,自引:1,他引:4
The present studies report erythropoietin (Ep) production in primary cultures of a human renal carcinoma from a patient with erythrocytosis that has been serially transplanted to BALB/c nude mice. The levels of erythropoietin in the culture media were estimated using the exhypoxic polycythemic mouse assay (EHPCMA), fetal mouse liver erythroid colony- forming technique (FMLC), and a radioimmunoassay (RIA). The spent culture media of the exponentially growing cells contained less than 10 mU/ml of Ep measured by RIA. However, after the cells became confluent, Ep levels (RIA) in the spent media showed a marked increase to approximately 300 mU/ml. Ep levels estimated using the FMLC and EHPCMA were approximately 2/3 and 1/10, respectively, of those measured by RIA. Rabbit antiserum to highly purified human urinary Ep (70,400 U/mg protein) was utilized for immunocytochemical (peroxidase-antiperoxidase method) localization of Ep in the cultured cells. Very few of the cells in exponential growth exhibited Ep-like immunoreactivity, whereas intense Ep-like immunoreactivity was observed in the cytoplasm of the cells maintained in culture for a prolonged period after reaching confluency. The most intense staining was observed in some of the cells forming domes. The domes developed after the cells reached confluency, and their numbers increased with increasing time in confluent culture, in parallel with the increase in Ep levels in the spent media. This primary cell culture system of a renal cell carcinoma maintained in nude mice, which produces immunologically and biologically active Ep, may provide a useful model for studies of the mechanism of Ep production. 相似文献
104.
Carlos E. Carvalho Rubens A. da Silva André W. Gil Márcio R. Oliveira Juliana A. Nascimento Deise A. A. Pires-Oliveira 《Journal of Physical Therapy Science》2015,27(3):705-710
[Purpose] The aim of this study was to compare age-related differences in balance and
anthropometric posture measurements of the foot and to determine any relationship between
them. [Subjects and Methods] Sixty-eight older and 42 younger adults participated in this
study. Foot posture was tested for four domains: 1) hallux flexion and extension range of
motion using a goniometer, 2) navicular height and 3) length of the foot using a
pachymeter, and 4) footprint (width of forefoot, arch index and hallux valgus). Balance
was tested under two conditions on a force platform: bipodal in 60-s trials and unipodal
in 30-s trials. The sway area of the center of pressure and velocity in the
anteroposterior and mediolateral directions were computed. [Results] Older individuals
showed significantly poorer balance compared with younger adults under in the unipodal
condition (center of pressure area 9.97 vs. 7.72 cm2). Older people presented a
significantly lower hallux mobility and higher values for width of the forefoot and
transverse arch index than younger adults. The correlations between all foot posture and
center of pressure parameters varied across groups, from weak to moderate
(r −0.01 to −0.46). Low hallux mobility was significantly related to
higher center of pressure values in older people. [Conclusion] These results have clinical
implications for balance and foot posture assessments.Key words: Posture, Aging, Foot 相似文献
105.
Immunoglobulin G from patients with heparin-induced thrombocytopenia binds to a complex of heparin and platelet factor 4 总被引:6,自引:3,他引:6
Heparin-induced thrombocytopenia (HIT) is an important complication of heparin therapy. Although there is general agreement that platelet activation in vitro by the HIT IgG is mediated by the platelet Fc receptor, the interaction among the antibody, heparin, and platelet membrane components is uncertain and debated. In this report, we describe studies designed to address these interactions. We found, as others have noted, that a variety of other sulfated polysaccharides could substitute for heparin in the reaction. Using polysaccharides selected for both size and charge, we found that reactivity depended on two independent factors: a certain minimum degree of sulfation per saccharide unit and a certain minimum size. Hence, highly sulfated but small (< 1,000 daltons) polysaccharides were not reactive nor were large but poorly sulfated polysaccharides. The ability of HIT IgG to recognize heparin by itself was tested by Ouchterlony gel diffusion, ammonium sulfate and polyethylene glycol precipitation, and equilibrium dialysis. No technique demonstrated reactivity. However, when platelet releasate was added to heparin and HIT IgG, a 50-fold increase in binding of radio-labeled heparin to HIT IgG was observed. The releasate was then depleted of proteins capable of binding to heparin by immunoaffinity chromatography. Only platelet factor 4-immunodepleted releasate lost its reactivity with HIT IgG and heparin. Finally, to determine whether the reaction occurred on the surface of platelets or in the fluid phase, washed platelets were incubated with HIT IgG or heparin and after a wash step, heparin or HIT IgG was added, respectively. Reactivity was only noted when platelets were preincubated with heparin. Consistent with these observations was the demonstration of the presence of PF4 on platelets using flow cytometry. These studies indicate that heparin and other large, highly sulfated polysaccharides bind to PF4 to form a reactive antigen on the platelet surface. HIT IgG then binds to this complex with activation of platelets through the platelet Fc receptors. 相似文献
106.
107.
Occlusal splint for sleep bruxism: an electromyographic associated to Helkimo Index evaluation 总被引:1,自引:0,他引:1
Leonardo Lopes do Nascimento César Ferreira Amorim Lilian Chrystiane Giannasi Claudia Santos Oliveira Sérgio Roberto Nacif Alecsandro de Moura Silva Daniela Fernandes Figueira Nascimento Leonardo Marchini Luis Vicente Franco de Oliveira 《Sleep & breathing》2008,12(3):275-280
This study aims to evaluate long-term effects of using an occlusal splint in patients with sleep bruxism (SB), using surface electromyography (EMG) of masseter and temporalis muscles, as well as the Helkimo Index. The subjects were 15 individuals aged from 19 to 29 years, bearers of SB, with presence of signs and symptoms of temporomandibular disorders (TMD), which never have used occlusal splints. The subjects answered the Helkimo's Index and underwent EMG before and after 60 days of occlusal splints use. There was no indication of a significant decrease in mean EMG levels over the therapy in the muscles. A significant decrease in TMD signs and symptoms were observed in SB patients after 60 days of occlusal splints therapy. 相似文献
108.
Busch MP; Laycock M; Kleinman SH; Wages JW Jr; Calabro M; Kaplan JE; Khabbaz RF; Hollingsworth CG 《Blood》1994,83(4):1143-1148
Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II. 相似文献
109.
Rare genomic rearrangement in a boy with Williams–Beuren syndrome associated to XYY syndrome and intriguing behavior 下载免费PDF全文
110.
Joycellane Alline do Nascimento Campos Ribeiro Alexandre Coellho Serquiz Priscila Fabíola dos Santos Silva Patrícia Batista Barra Medeiros Barbosa Tarcísio Bruno Montenegro Sampaio Raimundo Fernandes de Araújo Junior Adeliana Silva de Oliveira Richele Janaina Araújo Machado Bruna Leal Lima Maciel Adriana Ferreira Uch?a Elizeu Antunes dos Santos Ana Heloneida de Araújo Morais 《Clinics (S?o Paulo, Brazil)》2015,70(2):136-143