全文获取类型
收费全文 | 31638篇 |
免费 | 1836篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 412篇 |
儿科学 | 693篇 |
妇产科学 | 653篇 |
基础医学 | 4078篇 |
口腔科学 | 2615篇 |
临床医学 | 2406篇 |
内科学 | 6649篇 |
皮肤病学 | 649篇 |
神经病学 | 2453篇 |
特种医学 | 835篇 |
外国民族医学 | 2篇 |
外科学 | 3471篇 |
综合类 | 242篇 |
一般理论 | 7篇 |
预防医学 | 3904篇 |
眼科学 | 438篇 |
药学 | 2477篇 |
中国医学 | 286篇 |
肿瘤学 | 1316篇 |
出版年
2023年 | 255篇 |
2022年 | 646篇 |
2021年 | 1095篇 |
2020年 | 732篇 |
2019年 | 889篇 |
2018年 | 1127篇 |
2017年 | 809篇 |
2016年 | 858篇 |
2015年 | 1008篇 |
2014年 | 1328篇 |
2013年 | 1655篇 |
2012年 | 2284篇 |
2011年 | 2509篇 |
2010年 | 1319篇 |
2009年 | 1050篇 |
2008年 | 1763篇 |
2007年 | 1783篇 |
2006年 | 1484篇 |
2005年 | 1339篇 |
2004年 | 1180篇 |
2003年 | 1091篇 |
2002年 | 957篇 |
2001年 | 692篇 |
2000年 | 668篇 |
1999年 | 523篇 |
1998年 | 222篇 |
1997年 | 167篇 |
1996年 | 138篇 |
1995年 | 134篇 |
1994年 | 124篇 |
1993年 | 112篇 |
1992年 | 324篇 |
1991年 | 279篇 |
1990年 | 292篇 |
1989年 | 259篇 |
1988年 | 235篇 |
1987年 | 164篇 |
1986年 | 195篇 |
1985年 | 169篇 |
1984年 | 118篇 |
1983年 | 103篇 |
1982年 | 88篇 |
1979年 | 146篇 |
1978年 | 76篇 |
1975年 | 80篇 |
1974年 | 77篇 |
1973年 | 77篇 |
1969年 | 97篇 |
1968年 | 74篇 |
1967年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Daniel B. Costa Christopher A. Fisher Kenneth B. Miller German A. Pihan David P. Steensma Richard J. Gibbons Douglas R. Higgs 《European journal of haematology》2006,76(5):432-435
Abstract: We describe a patient with acquired alpha-thalassemia myelodysplastic syndrome (ATMDS). A previously healthy 66-year-old man presented with hemoglobin of 9.3 g/dL, mean corpuscular volume 59 fL, and a bone marrow aspirate with increased erythroid precursors and hypolobulated megakaryocytes. Hemoglobin H inclusions were seen in most red cells after 1% brilliant cresyl blue supravital stain of the peripheral blood. At the molecular level, we identified of a novel mutation in the most 3' exon of the ATRX gene ( C GA→ T GA substitution in codon 2407) resulting in a premature termination codon (p.R2407X). This case provides further evidence for a link between ATRX mutations and ATMDS, and suggests a possible role for the conserved Q-box element in ATRX function. 相似文献
32.
Catarina Gonzalez da Silva Karl Magnus Petersson Luís Faísca Martin Ingvar Alexandra Reis 《Journal of clinical and experimental neuropsychology》2004,26(2):266-277
Semantic verbal fluency tasks are commonly used in neuropsychological assessment. Investigations of the influence of level of literacy have not yielded consistent results in the literature. This prompted us to investigate the ecological relevance of task specifics, in particular, the choice of semantic criteria used. Two groups of literate and illiterate subjects were compared on two verbal fluency tasks using different semantic criteria. The performance on a food criterion (supermarket fluency task), considered more ecologically relevant for the two literacy groups, and an animal criterion (animal fluency task) were compared. The data were analysed using both quantitative and qualitative measures. The quantitative analysis indicated that the two literacy groups performed equally well on the supermarket fluency task. In contrast, results differed significantly during the animal fluency task. The qualitative analyses indicated differences between groups related to the strategies used, especially with respect to the animal fluency task. The overall results suggest that there is not a substantial difference between literate and illiterate subjects related to the fundamental workings of semantic memory. However, there is indication that the content of semantic memory reflects differences in shared cultural background--in other words, formal education--, as indicated by the significant interaction between level of literacy and semantic criterion. 相似文献
33.
L Bonina M Carbone P Mastroeni G B Costa P Mastroeni 《Journal of chemotherapy (Florence, Italy)》1992,4(6):353-357
This study was undertaken to investigate the efficacy of rufloxacin, a new quinolone which is interesting due to its pharmacokinetics characterized by a long plasma half-life, in the treatment of systemic salmonella infections in the mouse typhoid model. Innately susceptible BALB/c and resistant CBA mice were used to investigate the efficacy of rufloxacin in controlling systemic salmonella infections when given for brief or prolonged periods. The present study shows that rufloxacin is not only very effective on both mouse strains, but can completely eradicate the salmonellae from livers and spleens when given early in the infection of CBA resistant mice. 相似文献
34.
Eric Vivier Antonio J. da Silva Melissa Ackerly Herbert Levine Christopher E. Rudd Paul Anderson 《European journal of immunology》1993,23(8):1872-1876
The CD16: ζ: γ receptor complex allows natural killer (NK) cells to recognize and eliminate antibody-coated target cells. Whereas the ectodomain of CD16 is the receptor for Fcγ domains of immunoglobulins, disulfide-linked homo- and heterodimers composed of ζ and γ are required for the cell surface expression, and signal transduction properties of the complex. Engagement of CD16 activates the tyrosine kinase pathway, which induces the tyrosine phosphorylation of several substrates, including the ζ subunit and the phospholipase C γ-1 and γ-2 isoforms. Here we show that CD 16 stimulation of either peripheral blood NK cells, leukemic NK cells, or Jurkat transformants expressing a CD16:ζ:γ receptor complex, results in the tyrosine phosphorylation of a 70 kDa ζ-associated protein (pp70). Similarly, a 70-kDa ζ-associated phosphoprotein in T cells has been shown to be a tyrosine kinase (ZAP-70). Peptide mapping analysis indicates that the 70-kDa ζ-associated phosphoproteins from T cells and NK cells are structurally indistinguishable. We conclude that the CD16:ζ:γ complex may use a ZAP-70-related non-receptor tyrosine kinase, in the CD16 signaling cascade leading to NK cell activation. 相似文献
35.
36.
F. Veiga Fernandes J. Coutinho M. P. Henriques B. da Silva A. Baptista A. I. Santos F. Godinho 《Transplant international》1992,5(Z1):S193-S195
A new technique of choledochoenterostomy was devised to solve some of the problems of enterobiliary anastomosis with a normal calibre. The distal extremity of the common bile duct is completely surrounded by the bowel mucosa to a length of 3 cm after seromyectomy of a bowel wall rectangle of 4 × 1 cm. Experimental studies in rats and dogs demonstrated that this procedure prevents the risks of anastomotic disruption and functions like a mechanical unidirectional valve, which has great efficacy in stopping enterobiliary reflux. Studies in ten patients with obstructive jaundice with an extrahepatic biliary dilation less than 1.2 cm diameter submitted to this procedure Confirmed the experimental results. All patients were asymptomatic, without jaundice and with normalization of the liver enzymes after 2 months. The permeability of the valvular anastomosis studied by cholangiography, the HIDA 99mTc test and manometry was quite similar to other classical biliary-enteric anastomosis. In contrast, anti-reflux efficacy was only demonstrated in patients with a valvular anastomosis. 相似文献
37.
38.
Geraldo F. Busatto Lyn S. Pilowsky Durval C. Costa John Mertehs Dirk Terriere Peter J. Ell Rachel Mulligan Michael J. Travis Josée E. Leysen Dominic Lui Sveto Gacinovic Wendy Waddington Anne Lingford-Hughes Robert W. Kerwin 《European journal of nuclear medicine and molecular imaging》1997,24(2):119-124
The mapping of 5-HT2 receptors in the brain using functional imaging techniques has been limited by a relative lack of selective radioligands.
Iodine-123 labelled 4-amino-N-[1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl]-5-iodo-2-methoxybenzamide (123I-5-I-R91150 or123I-R93274) is a new ligand for single-photon emission tomography (SPET), with high affinity and selectivity for 5-HT2A receptors. This study reports on preliminary123I-5-I-R91150 SPET, wholebody and blood distribution findings in five healthy human volunteers. Maximal brain uptake was approximately
2% of total body counts at 180 min post injection (p.i.). Dynamic SPET sequences were acquired with the brain-dedicated, single-slice
multi-detector system SEM-810 over 200 min p.i. Early peak uptake (at 5 min p.i.) was seen in the cerebellum, a region free
from 5HT2A receptors. In contrast, radioligand binding in the frontal cortex increased steadily over time, up to a peak at approximately
100–120 min p.i. Frontal cortex-cerebellum activity ratios reached values of 1.4, and remained stable from approximately 100
min p.i. onwards. Multi-slice SPET sequences showed a pattern of regional variation of binding compatible with the autoradiographic
data on the distribution of 5-HT2A receptors in (cerebral cortex>striatum>cerebellum). These findings suggest that123I-5-I-R91150 may be used for the imaging of 5-HT2A receptors in the living human brain with SPET. 相似文献
39.
40.
Ana Sánchez-Romero Israel Oliver David Costa Albina Orduña Javier Lacueva Francisco Pérez-Vicente Antonio Arroyo Rafael Calpena 《Clinical & translational oncology》2006,8(4):294-295
Lung cancer is the most prevalent malignancy in western countries and most of the patients present at advanced stages, but
single splenic metastasis is exceptional instead. We report on a case of a seventy-three-year old male presenting with non-hemoptoic
productive cough, constitutional syndrome and pain in the left lower quadrant. Physical examination and complementary radiological
and hystologycal procedures revealed the presence of an adenocarcinoma of the left lung with probable splenic metastasis.
The patient underwent splenectomy, which confirmed the diagnose of splenic metastasis of lung adenocarcinoma and, secondly,
lung resection was performed. Topics about lung cancer metastasis are discussed. 相似文献