全文获取类型
收费全文 | 20619篇 |
免费 | 1226篇 |
国内免费 | 204篇 |
专业分类
耳鼻咽喉 | 169篇 |
儿科学 | 359篇 |
妇产科学 | 331篇 |
基础医学 | 2924篇 |
口腔科学 | 677篇 |
临床医学 | 1883篇 |
内科学 | 5393篇 |
皮肤病学 | 232篇 |
神经病学 | 2134篇 |
特种医学 | 709篇 |
外科学 | 3050篇 |
综合类 | 69篇 |
一般理论 | 3篇 |
预防医学 | 1026篇 |
眼科学 | 260篇 |
药学 | 1628篇 |
中国医学 | 68篇 |
肿瘤学 | 1134篇 |
出版年
2023年 | 132篇 |
2022年 | 344篇 |
2021年 | 584篇 |
2020年 | 404篇 |
2019年 | 510篇 |
2018年 | 629篇 |
2017年 | 460篇 |
2016年 | 522篇 |
2015年 | 603篇 |
2014年 | 794篇 |
2013年 | 973篇 |
2012年 | 1552篇 |
2011年 | 1596篇 |
2010年 | 883篇 |
2009年 | 791篇 |
2008年 | 1244篇 |
2007年 | 1347篇 |
2006年 | 1161篇 |
2005年 | 1226篇 |
2004年 | 1127篇 |
2003年 | 999篇 |
2002年 | 953篇 |
2001年 | 236篇 |
2000年 | 229篇 |
1999年 | 237篇 |
1998年 | 225篇 |
1997年 | 158篇 |
1996年 | 116篇 |
1995年 | 117篇 |
1994年 | 110篇 |
1993年 | 103篇 |
1992年 | 150篇 |
1991年 | 107篇 |
1990年 | 90篇 |
1989年 | 83篇 |
1988年 | 81篇 |
1987年 | 73篇 |
1986年 | 81篇 |
1985年 | 60篇 |
1984年 | 65篇 |
1983年 | 45篇 |
1982年 | 42篇 |
1981年 | 38篇 |
1980年 | 35篇 |
1978年 | 25篇 |
1974年 | 23篇 |
1973年 | 27篇 |
1970年 | 25篇 |
1925年 | 23篇 |
1922年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Atomic absorption spectrophotometry (AAS) for the evaluation of metallosis in prostheses and artificial organs: a new approach. 总被引:1,自引:0,他引:1
G Pierini M Fini G Giavaresi S Dallari M Brayda Bruno M Rocca N Nicoli Aldini R Giardino 《The International journal of artificial organs》1999,22(7):522-527
To study the presence of metals in body fluids and tissues after implantation of metallic biomaterials and possible related diseases, a new approach in Atomic Absorption Spectrophotometry (AAS) was developed. This technique was compared to three traditional methods: mineralisation with acid digestion (method A) also known as "wet method", dry ashing (with or without oxygen) (method B); classic Kjeldaal (method C). The new approach (method D) modifies the mineralisation phase and the instrument operating instructions. Al, Na, Cr, K, Ni, Co, Ti, Fe, Hg, Pb, V, Sb and Cu levels were tested with the four methods on bone, muscle, cartilage, skin, brain, lymph nodes, blood, urine, and hair. Test results were checked by the addition method. Results demonstrated a significantly higher percentage of Al, Cr, Ni, Ti and Hg recovery with the new approach. The advantages of method D are no residue, no redox reaction, insignificant loss of analytes and enhanced sensitivity (at ppb level vs ppm of the other methods). This approach should be considered especially when testing heavy metals and complex matrices. Its disadvantages are that it is more time consuming and requires the presence of an operator. 相似文献
62.
Bruno Amduri Khalid Berrada Bernard Boutevin Michel Mlas Roy D. Bowden 《Macromolecular chemistry and physics.》1993,194(11):3001-3014
The synthesis of novel telechelic monodispersed diols produced from the radical monoaddition of an excess of 10-undecenol with novel α, ω-dithiols, initiated by peroxides, is presented. The telechelic dithiols employed were prepared from nonconjugated dienes and a commercially available dithiol, or by esterification of adipic acid with 2-mercaptoethanol. From these dithiols, the diols were selectively obtained in high yields. Such α, ω-dihydroxylated compounds were characterized by both 1H and 13C NMR spectroscopy. The diol which exhibits the ester functions shows excellent solubility in common organic solvents contrarily to the other ones. The physical properties (Tg, Tm and decomposition temperatures) of these diols were compared and it is noted that the thermostability of these monodispersed telechelic diols is much better than those of the polydispersed commercially available ones such as poly(ethylene glycol)s or poly(tetramethylene glycol)s. 相似文献
63.
Gene therapy of cancer based on interleukin 12 总被引:3,自引:0,他引:3
Tumor formation and growth depends mainly on the inability of the organism to elicit a potent immune response, and on the formation of new blood vessels that enable tumor nutrition. Interleukin-12 (IL-12) therapy can target both processes. And IL-12-based gene therapy may restrict IL-12 production to the relevant site in order to obtain enhanced antitumor activity and reduced toxicity. In the clinical setting, IL-12 gene transfer can be used either to improve the pharmacokinetic/pharmacodynamic profile of the cytokine, to transduce dendritic cells or to enhance the efficiency of antitumor vaccination. It can also synergize with other procedures involving the simultaneous transfer of other transgenes or non-gene based strategies. The strong anti-tumoral power shown in many different animal models has not been found in early clinical trials in which cancer patients were treated by peritumoral injections of autologous fibroblasts producing IL-12, intratumoral injections of an adenoviral vector encoding human IL-12 genes, or intratumoral injection of autologous dendritic cells transduced ex vivo with this same adenoviral vector. However, these trials have set the proof-of-concept that local production of IL-12 inside a tumor can stimulate tumor infiltration by effector immune cells and that in some cases it is followed by tumor regression. From the many questions that arise after these disappointing results the most relevant concerns the duration and intensity of transgene expression and the capability to monitor this topics in vivo. New vectors that might achieve regulated, long-term production of this cytokine might have better results and merit clinical testing. 相似文献
64.
Viollet L Zarhrate M Maystadt I Estournet-Mathiaut B Barois A Desguerre I Mayer M Chabrol B LeHeup B Cusin V Billette De Villemeur T Bonneau D Saugier-Veber P Touzery-De Villepin A Delaubier A Kaplan J Jeanpierre M Feingold J Munnich A 《European journal of human genetics : EJHG》2004,12(6):483-488
Chronic distal spinal muscular atrophy (Chronic DSMA, MIM (*)607088) is a rare autosomal recessive disorder characterized by a progressive motor weakness and muscular atrophy, predominating in the distal parts of the limbs. A form of Chronic DSMA gene has been previously mapped to chromosome 11q13 in the 10.3 cM interval defined by loci D11S1889 and D11S1321. By linkage analysis in 12 European Chronic DSMA families, we showed that a disease gene maps to chromosome 11q13.3 (Z(max)=6.66 at theta=0.00 at the DSM4 locus) and suggested that this condition is genetically homogeneous. Recombination events allowed us to reduce the genetic interval to a 2.6 cM region, telomeric to the IGHMBP2 gene, excluding this gene as the disease causing gene in Chronic DSMA. Moreover, partial linkage disequilibrium was found between three rare alleles at loci D11S1369, DSM4 and D11S4184 and the mutant chromosome in European patients. Analysis of the markers at these loci strongly suggests that most Chronic DSMA chromosomes are derived from a single ancestor. Refinement of the Chronic DSMA locus will hopefully allow to test candidate genes and lead to identification of the disease-causing mutations. 相似文献
65.
Bruno Dallapiccola Giuliana Alimena Viviana Brinchi Giancarlo Isacchi Enrico Gandini 《Cancer Genetics and Cytogenetics》1980,2(4):349-360
Chromosome investigations were carried out in 7 patients with Fanconi's anemia, type Estren-Dameshek. The frequency and types of chromosome instability found in cultured lymphocytes were in accord with those detected in individuals with classical Fanconi's anemia. The break-point distribution indicates a significant excess of breaks in chromosomes No. 1, 2, and 7 and a deficit in No. 18 and X and Y chromosomes. There was a clear clustering of breaks at certain locations in chromosomes No. 1, 2, 3, 7, 9, and 14. The location of the breaks with respect to the bands demonstrated an almost exclusive involvement of the lighter bands, regardless of the banding method used. These results suggest that most breaks take place in the interbands between the G and R bands. In all patients, chromosome instability was less frequent in direct bone marrow preparations than in lymphocyte cultures. However, cultured bone marrow cells showed a significant increase of chromosome aberrations. On the whole, the chromosome data derived from this series of patients are in agreement with those obtained in individuals with classical Fanconi's anemia and give no support to the idea of cytogenetic heterogeneity between subjects affected by these two forms of childhood aplastic anemia. 相似文献
66.
67.
Ohne Zusammenfassung 相似文献
68.
Leopoldo Zelante Lucio Vigliaroli Rita Mingarelli Bruno Dallapiccola 《American journal of medical genetics. Part A》1993,45(4):534-535
We report the seventeenth case of the recessive form of the DOOR syndrome. The parents were Guatemalan and not known to be consanguineous. The patient had developmental delay, severe sensorineural deafness, and abnormal nails and phalanges in the hands and feet. Urinary 2-oxoglutarate excretion was normal. The patient was among a subset of DOOR syndrome patients may be useful in discussing the prognosis for newly identified cases. © 1993 Wiley-Liss, Inc. 相似文献
69.
Mitochondrial import and enzymatic activity of PINK1 mutants associated to recessive parkinsonism 总被引:17,自引:0,他引:17
Silvestri L Caputo V Bellacchio E Atorino L Dallapiccola B Valente EM Casari G 《Human molecular genetics》2005,14(22):3477-3492
Parkinson's disease (PD) is a progressive neurodegenerative illness associated with a selective loss of dopaminergic neurons in the nigrostriatal pathway of the brain. Despite the overall rarity of the familial forms of PD, the identification of single genes linked to the disease has yielded crucial insights into possible mechanisms of neurodegeneration. Recently, a putative mitochondrial kinase, PINK1, has been found mutated in an inherited form of parkinsonism. Here, we describe that PINK1 mutations confer different autophosphorylation activity, which is regulated by the C-terminal portion of the protein. We also demonstrate the mitochondrial localization of both wild-type and mutant PINK1 proteins unequivocally and prove that a short N-terminal part of PINK1 is sufficient for its mitochondrial targeting. 相似文献
70.
Souriau J Gimenes M Blouin C Benbrik I Benbrik E Churakowskyi A Churakowskyi B 《American journal of medical genetics. Part A》2005,135(3):278-281
Kabuki syndrome (KS) is associated with multiple organ system involvement. Characteristic features include long palpebral fissures with everted lower lids, prominent ears, skeletal abnormalities, mental retardation, and short stature. An increased incidence of infection has been reported in KS, and a few patients have been noted to have immune defects. However, the frequency and severity of the immune deficiency has not been clearly defined. Immunologic evaluation of 19 consecutive individuals with KS was performed at The Children's Hospital of Philadelphia. Decreased IgA levels were noted in 15/19 individuals (79%), 2 of whom had undetectable levels. Eight patients (42%) also had low total IgG levels. Specific IgG subclass abnormalities were found in 6 of 13 patients evaluated. IgM levels were less frequently decreased. One patient failed to generate anti-tetanus antibodies despite immunization. This study suggests that hypogammaglobulinemia is a frequent finding in children with KS. The pattern of antibody abnormalities seen in children with KS resembles common variable immune deficiency (CVID). Due to this increased susceptibility to infection, children with KS should have immunologic evaluations at the time of diagnosis in order to reduce preventable morbidity and mortality. 相似文献