全文获取类型
收费全文 | 457篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 2篇 |
妇产科学 | 5篇 |
基础医学 | 77篇 |
口腔科学 | 33篇 |
临床医学 | 32篇 |
内科学 | 64篇 |
皮肤病学 | 27篇 |
神经病学 | 40篇 |
特种医学 | 2篇 |
外科学 | 47篇 |
综合类 | 2篇 |
预防医学 | 86篇 |
眼科学 | 3篇 |
药学 | 31篇 |
肿瘤学 | 23篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 9篇 |
2020年 | 1篇 |
2019年 | 7篇 |
2018年 | 16篇 |
2017年 | 3篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 30篇 |
2011年 | 48篇 |
2010年 | 29篇 |
2009年 | 16篇 |
2008年 | 32篇 |
2007年 | 40篇 |
2006年 | 45篇 |
2005年 | 32篇 |
2004年 | 33篇 |
2003年 | 25篇 |
2002年 | 25篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有474条查询结果,搜索用时 15 毫秒
1.
Summary Immunoreactivity for gamma-aminobutyric acid is located in one morphologically-defined class of nerve cell body in the myenteric plexus of the guinea pig small intestine. These are a subgroup of the Dogiel type I nerve cells, characterized by their lamellar dendrites, about 1 m thick and flattened in the plane of the myenteric plexus, and one (or rarely two) long axonal process that extends to either the longitudinal or the circular muscle. At an ultrastructural level the dendrites were characterized by their open cytoplasm in which were scattered granular vesicles, pale mitochondria, Golgi apparatus and endoplasmic reticulum. A large proportion of the dendritic surface was in direct contact with the extra-ganglionic space. In the cell body region, which was away from the ganglion surface, the nucleus was surrounded by a thin rim of cytoplasm. The cytoplasmic features are quite distinct from those of Dogiel type II neurons but they were shared by many other non-immunoreactive neurons. Synaptic inputs, which were all non-immunoreactive, were found on the dendrites, cell bodies, axon hillocks and axons of the gamma-aminobutyric acid-immunoreactive neurons. The predominant vesicle type in the presynaptic elements was the small clear vesicle, 40–60 nm in diameter. Based on two gamma-aminobutyric acid-immunoreactive cells that were examined in serial section, about 40–50% of synapses are dendritic, 20–25% are somatic, and 30–35% are on the axon hillock or first 50–70 m of the axon. No synapses formed by immunoreactive varicosities were found on non-immunoreactive neurons or in the neuropil of the myenteric ganglia. Moreover, the lamellar dendrites or soma of gamma-aminobutyric acid neurons were never presynaptic elements forming relationships with other elements in the ganglia. It is concluded that the gamma-aminobutyric acid reactive Dogiel type I neurons are motor neurons providing inputs to the circular and longitudinal muscle layers. 相似文献
2.
S. M. S. R. Araújo C. C. Silva S. G. Pompolo F. Perfectti J. P. M. Camacho 《Chromosome research》2002,10(7):607-613
Extensive variation in the size of the short (heterochromatic) arm of chromosome 14 was found in the wasp Trypoxylon (Trypargilum) albitarse. Ten different variants were differentiated by size and C-banding pattern. Fluorescent in-situ hybridization (FISH) revealed that ribosomal DNA in this species is clustered in the darkly C-banded parts of the heterochromatic
short arm of chromosome 14. On this basis, we got an indirect estimate of the amount of rDNA from the area of these dark C-bands.
The significant absence in males of the three chromosome variants with lower amounts of rDNA indicates that these three variants
are lethal in this sex, and suggests the existence of a threshold marking the minimum amount of rDNA which is tolerable in
haploidy. This implies about 4% genetic load in the population caused by variation in rDNA amount.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Helicobacter pylori seropositivity and IL-1B C-31T polymorphism among Japanese Brazilians 总被引:2,自引:0,他引:2
Uno M Hamajima N Ito LS Oba SM Marie SK Shinjo SK Onda H Saito T Takezaki T Tajima K Tominaga S 《International journal of molecular medicine》2002,10(3):321-326
We reported previously that anti-Helicobacter pylori antibody seropositivity (HP+) had an association with interleukin 1B (IL-1B) C-31T genotype, especially among smokers. This study examined the association for Japanese Brazilians. In this cross-sectional study, voluntary participation was announced through Japanese Brazilian communities in Sao Paulo, Curitiba, Mogi das Cruzes, and Mirandopolis; 963 Japanese Brazilians (399 males and 564 females) aged 33-69 years participated. Lifestyle data and peripheral blood were collected. An anti-HP IgG antibody test and genotyping for IL-1B C-31T and IL-1RN 86 bp VNTR were independently conducted. The genotype frequency of the IL-1B polymorphism among 947 individuals was 23.9% for C/C genotype, 45.6% for C/T genotype, and 30.5% for T/T genotype. Sex-age-adjusted odds ratio (aOR) of HP+ was 1.30 (95% confidence interval, 0.94-1.81) for C/T genotype and 1.45 (1.02-2.07) for T/T genotype relative to C/C genotype. The aOR for 127 current smokers was 2.45 (0.91-6.55) for C/T and 3.49 (1.17-10.46) for T/T, while that for 667 never smokers was 1.21 (0.82-1.78) and 1.36 (0.90-2.05), respectively. The corresponding figures were 2.42 (1.16-5.02) and 3.00 (1.33-6.78) for 226 current drinkers, and 1.21 (0.82-1.78) and 1.36 (0.90-2.05) for 667 non-drinkers. The difference in the OR was observed for milk consumption, salty pickled vegetable eating, and physical exercise practice. 4/4 Genotype of IL-1RN 86 bp VNTR was 84.8%, and had no association with the HP seropositivity. The observed association between HP+ and IL-1B -31TT indicated that the genetic trait also influences the susceptibility to HP for Japanese in Brazil. 相似文献
4.
Oliveira CJ Carvalho LF Fernandes SA Tavechio AT Menezes CC Domingues FJ 《Microbial drug resistance (Larchmont, N.Y.)》2002,8(4):407-411
The aim of this study was to determine the antimicrobial resistance patterns of Salmonella strains isolated from slaughter-age pigs and environmental samples collected at modern swine raising facilities in Brazil. Seventeen isolates of six serotypes of Salmonella enterica subsp. enterica were isolated out of 1,026 collected samples: Salmonella Typhimurium (1), Salmonella Agona (5), Salmonella Sandiego (5), Salmonella Rissen (1), Salmonella Senftenberg (4), and Salmonella Javiana (1). Resistance patterns were determined to extended-spectrum penicillin (ampicillin), broad-spectrum cephalosporins (cefotaxime and ceftriaxone), aminoglycosides (streptomycin, neomycin, gentamicin, amikacin, and tobramycin), narrow-spectrum quinolone (nalidixic acid), broad-spectrum quinolone (ciprofloxacin and norfloxacin), tetracycline, trimethoprim, and chloramphenicol. Antimicrobial resistance patterns varied among serotypes, but isolates from a single serotype consistently showed the same resistance profile. All isolates were resistant to tetracycline, streptomycin, and nalidixic acid. One isolate, Salmonella Rissen, was also resistant to cefotaxime and tobramycin. All serotypes were susceptible to ceftriaxone, norfloxacin, ciprofloxacin, ampicillin, gentamicin, and chloramphenicol. The high resistance to tetracycline and streptomycin may be linked to their common use as therapeutic drugs on the tested farms. No relation was seen between nalidixic acid and fluoroquinolone resistance. 相似文献
5.
Aline S. Hora Sueli A. Taniwaki Nathana B. Martins Nataly N.R. Pinto Andr E. Schlemper Andr L.Q. Santos Matias P.J. Szab Paulo E. Brando 《Emerging infectious diseases》2021,27(4):1177
We obtained the complete sequence of a novel poxvirus, tentatively named Brazilian porcupinepox virus, from a wild porcupine (Coendou prehensilis) in Brazil that had skin and internal lesions characteristic of poxvirus infection. The impact of this lethal poxvirus on the survival of this species and its potential zoonotic importance remain to be investigated. 相似文献
6.
Waleska Teixeira Caiaffa Francisco Incio Bastos Fernando Augusto Proietti ngela Cristina Maia Reis Sueli Aparecida Mingoti Denise Gandolfi Denise Doneda AjUDE-Brasil II Project 《The International journal on drug policy》2003,14(5-6):365
The study describes practices relating to syringe acquisition and disposal by Syringe Exchange Programme (SEP) participants. A cross-sectional multi-city study enrolled 857 injection drug users (IDUs) from six SEPs in different Brazilian regions, and assessed self-reported acquisition and disposal behaviours. Seven hundred and nine males (82.9%) and 146 females (17.1%) were recruited through outreach and interviewed, most from the streets or their neighbourhoods (54.1%). The average age was 28.5 years; 76.4% reported injecting cocaine in the past 6 months. Sources for acquiring new syringes differed significantly between time of injection drug use debut and the 6 months prior to interview. Fifty-three percent of IDUs reported acquiring their syringes in pharmacies when they initiated injection drug use, whereas most reported acquiring new syringes in the 6 months before interview from several simultaneous sources: 69% through SEPs; 58% through pharmacies; 36% from friends and/or sexual partners; and 17% from other health services. Across SEPs, acquisition and disposal varied widely. Most interviewees discarded their syringes on the streets, in open fields, or in the garbage or sewage. Restrictions on syringe availability and unsafe practices may be functioning as barriers to the public health recommendation of one-time use of sterile syringes for IDUs and discouraging community support to SEPs. Further increase in access to legal, inexpensive and timely sterile syringes, as well as counselling about the merits of one-time use and safer disposal must be reinforced as part of efforts to minimise high-risk behaviours and curb the spread of blood-borne infections. 相似文献
7.
Clarke IJ Scott CJ Rao A Pompolo S Barker-Gibb ML 《Journal of neuroendocrinology》2000,12(11):1105-1111
Sheep experience well-documented seasonal changes in reproductive activity and voluntary food intake (VFI). Within the hypothalamus, neurones that express neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) have been implicated in the regulation of reproduction and appetite. In this study, we aimed to determine the extent to which the expression of these two neuronal systems is linked to the seasonal reproductive cycle and/or the seasonal appetite cycle. VFI in our sheep reaches a nadir in August with no difference occurring between December and February. We examined the brains of ovariectomized (OVX) female sheep (n=5-7) that were killed during the breeding season (February) or during the early or late nonbreeding season (August and December, respectively). The brains of these animals were perfused with paraformaldehyde and processed for in situ hybridization histochemistry, using ribonucleotide probes labelled with 35S. The number of NPY and POMC cells and the number of silver grains per cell were counted using an image analysis system. For NPY, the number of cells counted in the arcuate nucleus/median eminence region and the number of silver grains per cell was significantly lower in animals killed during August than in animals killed in February or December. The number of grains per cell over NPY cells was also significantly lower in animals killed during August. For POMC, the number of cells was lower in February than in August and December. Similarly, the number of grains per cell for POMC were lower in February than in August and December. VFI was significantly lower in animals during August than at other times of the year. We conclude that in OVX ewes: (i) NPY gene expression is lower at the time of the year when VFI is reduced and (ii) POMC gene expression is greater at the time of the nonbreeding season than during the breeding season. Because these results were obtained in OVX animals, the changes appear to be independent of alterations in the secretion and/or action of ovarian steroids. Thus, the activity of NPY neurones appears to relate to changes in appetite whereas changes in POMC expression may be relevant to the seasonal breeding cycle. 相似文献
8.
Sueli Gardim Cláudia S. Rocha Carlos E. Almeida Daniela M. Takiya Marco T. A. da Silva Daniela L. Ambrósio Regina M. B. Cicarelli Jo?o A. da Rosa 《The American journal of tropical medicine and hygiene》2013,89(4):766-774
The phylogenetic relationships among species of
Triatoma matogrossensis subcomplex (
T. baratai,
T. guazu,
T. matogrossensis,
T. sordida,
T. vandae, and
T. williami) was addressed by using fragments of cytochrome oxidase I (COI), 16S rDNA (16S), and cytochrome
b (Cytb) through Bayesian and parsimony analyses. We did not recover a monophyletic
T. matogrossensis subcomplex, and their members were found clustered in three strongly supported clades, as follows: i)
T. jurbergi +
T. matogrossensis +
T. vandae +
T. garciabesi +
T. sordida; ii) with
T. guasayana as the sister group of clade (i); and iii)
T. williami +
T. guazu, however not closely related to the clade formed by the previously mentioned species. The other two endemic species from Central-Western Brazil,
T. baratai and
T. costalimai, were not recovered with strong clade support as related to other members of this subcomplex. Results call for a further revision in the classification of the subcomplexes within the genus
Triatoma. 相似文献
9.
Fernanda Monego Rafael Silva Duarte Sueli Massumi Nakatani Wildo Navegantes Araújo Irina Nastassja Riediger Sonia Brockelt Verena Souza Jamyra Iglesias Cataldo Rubens Clayton da Silva Dias Alexander Welker Biondo 《The Brazilian journal of infectious diseases》2011,15(5):436-441
ObjectiveOne hundred thirty-one cases of postsurgical infections were reported in Southern Region of Brazil between August 2007 and January 2008. Thirty-nine (29.8%) cases were studied; this report describes epidemiological findings, species identification, antimicrobial susceptibility and clonal diversity of rapidly growing mycobacteria isolated in this outbreak.MethodsAll 39 isolates were analyzed by Ziehl-Nielsen stained smear, bacterial culture and submitted to rpoB partial gene sequencing for identification. The isolates were also evaluated for their susceptibility to amikacin, cefoxitin, clarithromycin, ciprofloxacin, doxycycline, tobramycin and sulfamethoxazole.ResultsThirty-six isolates out of the confirmed cases were identified as Mycobacterium massiliense and the remaining three were identified as Mycobacterium abscessus, Mycobacterium chelonae and Mycobacterium fortuitum. All M. massiliense isolates were susceptible to amikacin (MIC90 = 8 μg/mL) and clarithromycin (MIC90 = 0.25 μg/mL) but resistant to cefoxitin, ciprofloxacin, doxycycline, tobramycin and sulfamethoxazole. Molecular analysis by pulsed-field gel electrophoresis clustered all 36 M. massiliense isolates and showed the same pattern (BRA 100) observed in three other outbreaks previously reported in Brazil.ConclusionsThese findings suggest a common source of infection for all patients and reinforce the hypotheses of spread of M. massiliense BRA100 in Brazilian hospital surgical environment in recent years. 相似文献
10.
Ana Carolina G. Zanetti Tais Milena Pantaleão de Souza Larissa de Souza Tressoldi João Mazzoncini de Azevedo-Marques Gabriel Elias Corrêa-Oliveira Amanda Heloisa Santana da Silva Isabela dos Santos Martin Kelly Graziani Giacchero Vedana Lucilene Cardoso Sueli Aparecida Frari Galera Edilaine Cristina da Silva Gherardi-Donato 《Archives of Psychiatric Nursing》2018,32(3):390-395