全文获取类型
收费全文 | 2349篇 |
免费 | 279篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 169篇 |
妇产科学 | 18篇 |
基础医学 | 402篇 |
口腔科学 | 76篇 |
临床医学 | 257篇 |
内科学 | 474篇 |
皮肤病学 | 110篇 |
神经病学 | 68篇 |
特种医学 | 360篇 |
外科学 | 188篇 |
综合类 | 31篇 |
预防医学 | 136篇 |
眼科学 | 19篇 |
药学 | 114篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 218篇 |
出版年
2022年 | 7篇 |
2021年 | 26篇 |
2020年 | 15篇 |
2019年 | 20篇 |
2018年 | 35篇 |
2017年 | 26篇 |
2016年 | 31篇 |
2015年 | 41篇 |
2014年 | 42篇 |
2013年 | 73篇 |
2012年 | 48篇 |
2011年 | 44篇 |
2010年 | 57篇 |
2009年 | 105篇 |
2008年 | 64篇 |
2007年 | 80篇 |
2006年 | 79篇 |
2005年 | 72篇 |
2004年 | 73篇 |
2003年 | 65篇 |
2002年 | 52篇 |
2001年 | 51篇 |
2000年 | 57篇 |
1999年 | 73篇 |
1998年 | 119篇 |
1997年 | 135篇 |
1996年 | 127篇 |
1995年 | 88篇 |
1994年 | 101篇 |
1993年 | 107篇 |
1992年 | 54篇 |
1991年 | 58篇 |
1990年 | 51篇 |
1989年 | 70篇 |
1988年 | 65篇 |
1987年 | 56篇 |
1986年 | 55篇 |
1985年 | 44篇 |
1984年 | 35篇 |
1983年 | 22篇 |
1982年 | 29篇 |
1981年 | 42篇 |
1980年 | 23篇 |
1979年 | 21篇 |
1978年 | 14篇 |
1977年 | 28篇 |
1976年 | 21篇 |
1975年 | 14篇 |
1974年 | 11篇 |
1966年 | 4篇 |
排序方式: 共有2654条查询结果,搜索用时 376 毫秒
101.
Andrew F. H. Payne Michael E. Dawson Anne M. Schell Kulwinder Singh Christopher G. Courtney 《Psychophysiology》2013,50(11):1065-1069
The fingers and feet have long been accepted as optimal anatomical recording sites for electrodermal activity. The available literature suggests that the feet are more responsive than the fingers. The present report compared skin conductance level (SCL) and responses (SCRs) from the left foot and the distal phalanges of the fingers on the nondominant hand among 19 participants. The principal results were (a) SCRs recorded from the fingers were significantly larger and more frequent with shorter latencies than SCRs from the foot, (b) SCL from the fingers was significantly higher than from the foot, (c) the fingers exhibited significantly greater discrimination conditioning than the foot, and (d) skin conductance measures recorded from the fingers and foot were significantly positively correlated. Specifically, our results demonstrate that the distal phalanges of the fingers are electrodermally more responsive than the abductor hallucis area of the foot. 相似文献
102.
Amaia Cipitria Johannes C. Reichert Devakar R. Epari Siamak Saifzadeh Arne Berner Hanna Schell Manav Mehta Michael A. Schuetz Georg N. Duda Dietmar W. Hutmacher 《Biomaterials》2013
The transplantation of autologous bone graft as a treatment for large bone defects has the limitation of harvesting co-morbidity and limited availability. This drives the orthopaedic research community to develop bone graft substitutes. Routinely, supra-physiological doses of bone morphogenetic proteins (BMPs) are applied perpetuating concerns over undesired side effects and cost of BMPs. We therefore aimed to design a composite scaffold that allows maintenance of protein bioactivity and enhances growth factor retention at the implantation site. Critical-sized defects in sheep tibiae were treated with the autograft and with two dosages of rhBMP-7, 3.5 mg and 1.75 mg, embedded in a slowly degradable medical grade poly(ε-caprolactone) (PCL) scaffold with β-tricalcium phosphate microparticles (mPCL–TCP). Specimens were characterised by biomechanical testing, microcomputed tomography and histology. Bridging was observed within 3 months for the autograft and both rhBMP-7 treatments. No significant difference was observed between the low and high rhBMP-7 dosages or between any of the rhBMP-7 groups and autograft implantation. Scaffolds alone did not induce comparable levels of bone formation compared to the autograft and rhBMP-7 groups. In summary, the mPCL–TCP scaffold with the lower rhBMP-7 dose led to equivalent results to autograft transplantation or the high BMP dosage. Our data suggest a promising clinical future for BMP application in scaffold-based bone tissue engineering, lowering and optimising the amount of required BMP. 相似文献
103.
P Martínez‐Montero M Muoz‐Calero E Vallespín J Campistol L Martorell MJ Ruiz‐Falc A Santana R Pons A Dinopoulos C Sierra J Nevado J Molano 《Clinical genetics》2013,84(6):566-571
Pelizaeus–Merzbacher disease (PMD) is caused in most cases by either duplications or point mutations in the PLP1 gene. This disease, a dysmyelinating disorder affecting mainly the central nervous system, has a wide clinical spectrum and its causing mutations act through different molecular mechanisms. Eighty‐eight male patients with leukodystrophy were studied. PLP1 gene analysis was performed by the Multiplex Ligation‐dependent Probe Amplification technique and DNA sequencing, and, in duplicated cases of PLP1, gene dosage was completed by using array‐CGH. We have identified 21 patients with mutations in the PLP1 gene, including duplications, short and large deletions and several point mutations in our cohort. A customized array‐CGH at the Xq22.2 area identified several complex rearrangements within the PLP1 gene region. Mutations found in the PLP1 gene are the cause of PMD in around 20% of the patients in this series. 相似文献
104.
Molecular cloning and structural analysis of genes from Zea mays (L.) coding for members of the ras-related ypt gene family. 下载免费PDF全文
K Palme T Diefenthal M Vingron C Sander J Schell 《Proceedings of the National Academy of Sciences of the United States of America》1992,89(2):787-791
We have isolated, cloned, and characterized two cDNAs from Zea mays (L.), denoted yptm1 and yptm2, encoding proteins related to the ypt protein family. Amino acid similarity scores with YPT1 from yeast and ypt from mouse are in the range of 70% for yptm1 and 74% for yptm2, respectively, whereas similarities with p21 ras and other ras-related proteins are less than 40%. Most amino acid residues showing identity are clustered in the GTP/GDP binding domain. In addition, two cysteine residues close to the C-terminal ends, known to be palmitoylated and necessary for membrane binding in all eukaryotic ras-related proteins that have been characterized so far, are conserved in the maize genes as well. Northern blot hybridization analysis of poly(A)+ mRNA from etiolated maize coleoptiles revealed single mRNA species of approximately the same size as the isolated cDNAs. The gene for yptm1 is expressed at very low levels in maize coleoptiles and tissue culture cells. The gene for yptm2 is expressed at higher levels and is differentially represented in RNAs isolated from various organs of maize plants, with its highest level in leaves and flowers. The structural similarity of the genes identified suggests that they could be involved in the control of secretory processes. 相似文献
105.
IgG autoantibodies eluted from RBCs of antiglobulin positive normal blood donors contained at least two antibody populations, an IgG autoantibody (Ab 1), and an IgG population (Ab 2) that agglutinated RBCs coated with some Rh(D) alloantibodies. Eight of 24 autoantibody eluates tested agglutinated 3 of 10 anti-Rh(D) sensitized RBCs. The agglutinating activity was inhibited specifically by preincubation of the autoantibody eluate with the reactive anti-D. The reaction did not require the Fc domain of the anti-Rh(D), since autoantibody eluates agglutinated RBCs coated with F(ab')2 prepared from the reactive anti-D sera. These findings indicate that the RBCs of some antiglobulin- positive blood donors contain an immunoglobulin auto-antiidiotype (Ab 2) against the RBC autoantibody (Ab 1) which is demonstrable through its cross-reactivity with selected Rh(D) alloantibodies. Identification of auto-antiidiotypes in RBC autoimmunity lends support to the idiotype- antiidiotype network hypothesis of immune regulation and is consistent with the bizarre and complex serology of autoimmune hemolytic anemia. The absence of clinical hemolysis in antiglobulin-positive normal blood donors suggests that immunoglobulin idiotype-antiidiotype interactions may play a role in modulating the effects of RBC autoimmunity. 相似文献
106.
We treated 51 patients with advanced malignant lymphoma refractory to conventional therapy with methyl-glyoxal-bis(guanylhydrazone) (methyl- GAG) at doses ranging from 400 to 800 mg/sq m. Therapy was started on a weekly schedule and was switched to every other week in responding patients at the onset of toxicity. Partial responses were observed in 6 of 13 evaluable patients with Hodgkin's disease (46%), 5 of 10 patients with diffuse poorly differentiated lymphocytic lymphoma (50%), 2 of 4 patients with nodular poorly differentiated lymphocytic lymphoma (50%), and 3 of 13 patients with diffuse histiocytic lymphoma (23%). Two of six patients with mycosis fungoides showed objective improvement in cutaneous disease. Toxicity was generally mild and included muscular weakness, myalgia, mucositis, and diarrhea; two patients developed bronchospasm following drug infusions. We conclude that methyl-GAG has major antitumor activity when administered on this schedule to patients with advanced malignant lymphoma. The low degree of toxicity, unique mechanism of action, and minimal myelosuppressive effects suggest that methyl-GAG will prove useful in future trials of combination chemotherapy regimens for the treatment of lymphoma. 相似文献
107.
Patient perspectives on de‐simplifying their single‐tablet co‐formulated antiretroviral therapy for societal cost savings 下载免费PDF全文
Objectives
The incremental costs of expanding antiretroviral (ARV) drug treatment to all HIV‐infected patients are substantial, so cost‐saving initiatives are important. Our objectives were to determine the acceptability and financial impact of de‐simplifying (i.e. switching) more expensive single‐tablet formulations (STFs) to less expensive generic‐based multi‐tablet components. We determined physician and patient perceptions and acceptance of STF de‐simplification within the context of a publicly funded ARV budget.Methods
Programme costs were calculated for patients on ARVs followed at the Southern Alberta Clinic, Canada during 2016 (Cdn$). We focused on patients receiving Triumeq® and determined the savings if patients de‐simplified to eligible generic co‐formulations. We surveyed all prescribing physicians and a convenience sample of patients taking Triumeq® to see if, for budgetary purposes, they felt that de‐simplification would be acceptable.Results
Of 1780 patients receiving ARVs, 62% (n = 1038) were on STF; 58% (n = 607) of patients on STF were on Triumeq®. The total annual cost of ARVs was $26 222 760. The cost for Triumeq® was $8 292 600. If every patient on Triumeq® switched to generic abacavir/lamivudine and Tivicay® (dolutegravir), total costs would decrease by $4 325 040. All physicians (n = 13) felt that de‐simplifying could be safely achieved. Forty‐eight per cent of 221 patients surveyed were agreeable to de‐simplifying for altruistic reasons, 27% said no, and 25% said maybe.Conclusions
De‐simplifying Triumeq® generates large cost savings. Additional savings could be achieved by de‐simplifying other STFs. Both physicians and patients agreed that selective de‐simplification was acceptable; however, it may not be acceptable to every patient. Monitoring the medical and cost impacts of de‐simplification strategies seems warranted.108.
109.
Dror Y; Gallagher R; Wara DW; Colombe BW; Merino A; Benkerrou M; Cowan MJ 《Blood》1993,81(8):2021-2030
We describe our 9-year experience with lectin-treated T-cell-depleted haplocompatible parental bone marrow transplantation (BMT) for 24 patients with severe combined immunodeficiency disease (SCID). Nineteen of 21 evaluable patients had T-cell engraftment; 2 of 11 patients tested had B-cell and monocyte engraftment. Fourteen of 24 (58%) patients are alive 7 months to 9.8 years post-BMT. Seventeen of 24 patients received pretransplant conditioning with chemotherapy and/or total body irradiation, and 8 of 24 received more than one transplant. Patients who received conditioning had a survival rate of 61% versus 57% for those who received no conditioning. None received graft-versus- host disease (GVHD) prophylaxis and no patient had acute or chronic GVHD greater than grade I. Kinetics and follow-up of immune recovery were analyzed in 14 patients who are greater than 1 year from transplant. Half of the patients showed evidence of T-cell function by 3 months and normal T-cell function by 4 to 7 months post-BMT. On average, T-cell numbers and subsets became normal 10 to 12 months posttransplant. Recovery of B-cell function was more delayed, although in most patients B-cell numbers and IgM levels were normal by 12 months post-BMT. B-cell function, as determined by isohemagglutinin titers or specific antibodies to pneumococcal polysaccharide, keyhole limpet hemocyanin, or tetanus toxoid, became normal in 10 of 14 patients 2 to 8 years post-BMT. Seven of the 14 are off gammaglobulin therapy. Production of isohemagglutinins tended to predict recovery of antibody response to pneumococcal polysaccharide (P < .064). Based on these results, we believe that haplocompatible BMT is an effective, curative treatment for patients with SCID who lack an HLA-matched related donor. 相似文献
110.
Elevated numbers of primitive Philadelphia chromosome-positive (Ph+) progenitors, including long-term culture-initiating cells (LTC-IC) as well as colony-forming cells (CFC), have been previously described in the blood of patients with chronic myeloid leukemia (CML) in chronic phase with high white blood cell counts. In the present study, which focused primarily on an analysis of circulating progenitors present in such patients at diagnosis, we discovered the frequent and occasionally exclusive presence of circulating normal (Ph-) LTC-IC, often at levels above those seen for LTC-IC in the blood of normal individuals. The presence of detectable numbers of circulating Ph- LTC-IC was independent of the fact that the same peripheral blood samples also contained elevated numbers of predominantly or exclusively Ph+ CFC. Interestingly, both the Ph+ and Ph- LTC-IC in these samples were CD34+CD71- and variably CD38- and Thy-1+, as previously documented for LTC-IC in normal marrow. Thus, neither CD38 nor Thy-1 expression was useful for discriminating between Ph+ and Ph- LTC-IC in mixed populations. Nevertheless, an association of these phenotypes with LTC- IC function did allow highly enriched (> 5% pure) suspensions of either Ph+ or Ph- LTC-IC to be obtained from selected samples of CML blood in which the initial LTC-IC population was either predominantly Ph+ or Ph- , respectively. These findings suggest that the mechanisms causing mobilization of leukemic stem cells in untreated CML patients may affect their normal counterparts. They also indicate a possible new source of autologous cells for the support of intensive therapy of CML patients. Finally, they provide a method for obtaining the most highly purified populations of Ph+ LTC-IC described to date. This method should be useful for further analyses of the molecular activities of these very primitive neoplastic cells. 相似文献