全文获取类型
收费全文 | 8435篇 |
免费 | 732篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 346篇 |
妇产科学 | 148篇 |
基础医学 | 968篇 |
口腔科学 | 271篇 |
临床医学 | 1072篇 |
内科学 | 1905篇 |
皮肤病学 | 133篇 |
神经病学 | 614篇 |
特种医学 | 575篇 |
外科学 | 905篇 |
综合类 | 153篇 |
一般理论 | 16篇 |
预防医学 | 884篇 |
眼科学 | 70篇 |
药学 | 521篇 |
2篇 | |
中国医学 | 2篇 |
肿瘤学 | 620篇 |
出版年
2022年 | 53篇 |
2021年 | 121篇 |
2020年 | 81篇 |
2019年 | 125篇 |
2018年 | 155篇 |
2017年 | 104篇 |
2016年 | 108篇 |
2015年 | 134篇 |
2014年 | 203篇 |
2013年 | 284篇 |
2012年 | 304篇 |
2011年 | 343篇 |
2010年 | 260篇 |
2009年 | 232篇 |
2008年 | 342篇 |
2007年 | 371篇 |
2006年 | 265篇 |
2005年 | 327篇 |
2004年 | 300篇 |
2003年 | 268篇 |
2002年 | 277篇 |
2001年 | 274篇 |
2000年 | 248篇 |
1999年 | 236篇 |
1998年 | 208篇 |
1997年 | 230篇 |
1996年 | 201篇 |
1995年 | 174篇 |
1994年 | 177篇 |
1993年 | 143篇 |
1992年 | 212篇 |
1991年 | 221篇 |
1990年 | 210篇 |
1989年 | 217篇 |
1988年 | 200篇 |
1987年 | 191篇 |
1986年 | 173篇 |
1985年 | 170篇 |
1984年 | 117篇 |
1983年 | 104篇 |
1982年 | 85篇 |
1981年 | 90篇 |
1980年 | 77篇 |
1979年 | 74篇 |
1978年 | 78篇 |
1977年 | 57篇 |
1976年 | 45篇 |
1975年 | 36篇 |
1972年 | 39篇 |
1969年 | 29篇 |
排序方式: 共有9250条查询结果,搜索用时 15 毫秒
91.
doublecortin is the major gene causing X-linked subcortical laminar heterotopia (SCLH) 总被引:12,自引:0,他引:12
des Portes V; Francis F; Pinard JM; Desguerre I; Moutard ML; Snoeck I; Meiners LC; Capron F; Cusmai R; Ricci S; Motte J; Echenne B; Ponsot G; Dulac O; Chelly J; Beldjord C 《Human molecular genetics》1998,7(7):1063-1070
Subcortical laminar heterotopia (SCLH), or 'double cortex', is a cortical
dysgenesis disorder associated with a defect in neuronal migration.
Clinical manifestations are epilepsy and mental retardation. This disorder,
which mainly affects females, can be inherited in a single pedigree with
lissencephaly, a more severe disease which affects the male individuals.
This clinical entity has been described as X- SCLH/LIS syndrome. Recently
we have demonstrated that the doublecortin gene, which is localized on the
X chromosome, is implicated in this disorder. We have now performed a
systematic mutation analysis of doublecortin in 11 unrelated females with
SCLH (one familial and 10 sporadic cases) and have identified mutations in
10/11 cases. The sequence differences include nonsense, splice site and
missense mutations and these were found throughout the gene. These results
provide strong evidence that loss of function of doublecortin is the major
cause of SCLH. The absence of phenotype-genotype correlations suggests that
X-inactivation patterns of neuronal precursor cells are likely to
contribute to the variable clinical severity of this disorder in females.
相似文献
92.
93.
D Hassine G Rougereau JM Feron MC Henry-Feugeas V Fabre JC Sadik E Schouman-Claeys 《Surgical and radiologic anatomy : SRA》1994,16(3):293-301
Summary The angular points are the ligamentous and tendinous structures that reinforce the posteromedial and posterolateral capsule of the knee and share in fixation of the posterior horns of the menisci. They are often damaged in acute injuries and this is usually associated with ruptures of the cruciate and collateral ligaments and may add to the degree of laxity. We describe the normal appearance of these structures in terms of the sectional anatomy, correlated with the lesional appearances of complete and incomplete ruptures and associated meniscal detachments as shown by clinical testing and arthrotomy findings.
IRM des points d'angle du genou : bases anatomiques et applications aux genoux traumatiques
Résumé Les points d'angle sont des structures ligamentaires et tendineuses qui renforcent la capsule postéro-médiale et postéro-latérale et participent à la fixation des cornes postérieures des ménisques. Leurs lésions, fréquentes au cours des traumatismes aigus, sont généralement associées à des ruptures des ligaments croisés et des ligaments collatéraux et peuvent être source d'une aggravation de la laxité. Nous rapportons, en corrélation avec l'anatomie en coupe, l'aspect normal de ces structures, et en corrélation avec les données de l'arthrotomie et du testing les aspects lésionnels observés au cours des traumatismes : ruptures complètes, incomplètes et désinsertions méniscales associées.相似文献
94.
Stein TP; Oram-Smith JC; Leskiw MJ; Wallace HW; Long LC; Leonard JM 《The American journal of physiology》1976,230(5):1321-1325
95.
96.
Griffin JF Spittle E Rodgers CR Liggett S Cooper M Bakker D Bannantine JP 《Clinical and diagnostic laboratory immunology》2005,12(12):1401-1409
This study was designed to develop a customized enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Johne's disease (JD) in farmed deer. Two antigens were selected on the basis of their superior diagnostic readouts: denatured purified protein derivative (PPDj) and undenatured protoplasmic antigen (PpAg). ELISA development was based on the antigen reactivity of the immunoglobulin G1 (IgG1) isotype, which is a highly specific marker for mycobacterial disease seroreactivity in deer. Sensitivity estimates and test parameters were established using 102 Mycobacterium paratuberculosis-infected animals from more than 10 deer herds, and specificity estimates were determined using 508 uninfected animals from 5 known disease-free herds. A receiver-operated characteristic analysis determined that at a cut point of 50 ELISA units, there was a specificity of 99.5% and sensitivities of 84.0% with PPDj antigen, 88.0% with PpAg, and 91.0% when the antigens were used serially in a composite test. Estimated sensitivity was further improved using recombinant protein antigens unique for M. paratuberculosis, which identified infected animals that were unreactive to PPDj or PpAg. While 80% of animals that were seropositive in the IgG1 ELISA had detectable histopathology, the assay could also detect animals with subclinical disease. The test was significantly less sensitive (75%) for animals that were culture positive for M. paratuberculosis but with no detectable pathology than for those with pathological evidence of JD (>90%). When the IgG1 ELISA was used annually over a 4-year period in a deer herd with high levels of clinical JD, it eliminated clinical disease, increased production levels, and reduced JD-related mortality. 相似文献
97.
Diversity of rotavirus strains among children with acute diarrhea in China: 1998-2000 surveillance study 总被引:24,自引:0,他引:24 下载免费PDF全文
Fang ZY Yang H Qi J Zhang J Sun LW Tang JY Ma L Du ZQ He AH Xie JP Lu YY Ji ZZ Zhu BQ Wu HY Lin SE Xie HP Griffin DD Ivanoff B Glass RI Gentsch JR 《Journal of clinical microbiology》2002,40(5):1875-1878
As part of a national rotavirus surveillance activity, we collected fecal specimens from 3,177 children with acute diarrhea in 10 regions of China between April 1998 and April 2000 and screened them for rotavirus. Rotavirus was detected in 41% (n = 1,305) of specimens, and in these, G1 was the predominant serotype (72.6%), followed by G3 (14.2%), G2 (12.1%), G4 (2.5%), G9 (0.9%), and G untypeable (0.7%). Among 327 G-typed strains tested for P genotype, 14 different P-G combinations were identified, with the globally common strains P[8]G1, P[4]G2, P[8]G3, and P[8]G4 representing 75.6% of all typed rotavirus strains. Among the uncommon strains, 11 were P[6]G9, and others included P[6]G1, P[6]G3, and five novel P-G combinations (P[9]G1, P[4]G1, P[4]G3, P[4]G4, and P[8]G2). Our results indicate that while the common rotavirus strains remain predominant, the diversity of strains is much greater than was previously recognized. 相似文献
98.
Singh DK Griffin DM Pacyniak E Jackson M Werle MJ Wisdom B Sun F Hout DR Pinson DM Gunderson RS Powers MF Wong SW Stephens EB 《Virology》2003,313(2):435-451
The simian-human immunodeficiency virus (SHIV)/ macaque model for human immunodeficiency virus type 1 has become a useful tool to assess the role of Vpu in lentivirus pathogenesis. In this report, we have mutated the two phosphorylated serine residues of the HIV-1 Vpu to glycine residues and have reconstructed a SHIV expressing this nonphosphorylated Vpu (SHIV(S52,56G)). Expression studies revealed that this protein was localized to the same intracellular compartment as wild-type Vpu. To determine if this virus was pathogenic, four pig-tailed macaques were inoculated with SHIV(S52,56G) and virus burdens and circulating CD4(+) T cells monitored up to 1 year. Our results indicate that SHIV(S52,56G) caused rapid loss in the circulating CD4(+) T cells within 3 weeks of inoculation in one macaque (CC8X), while the other three macaques developed no or gradual numbers of CD4(+) T cells and a wasting syndrome. Histological examination of tissues revealed that macaque CC8X had lesions in lymphoid tissues (spleen, lymph nodes, and thymus) that were typical for macaques inoculated with pathogenic parental SHIV(KU-1bMC33) and had no lesions within the CNS. To rule out that macaque CC8X had selected for a virus in which there was reversion of the glycine residues at positions 52 and 56 to serine residues and/or compensating mutations occurred in other genes associated with CD4 down-regulation, sequence analysis was performed on amplified vpu sequences isolated from PBMC and from several lymphoid tissues at necropsy. Sequence analysis revealed a reversion of the glycine residues back to serine residues in this macaque. The other macaques maintained low virus burdens, with one macaque (P003) developing a wasting syndrome between months 9 and 11. Histological examination of tissues from this macaque revealed a thymus with severe atrophy that was similar to that of a previously reported macaque inoculated with a SHIV lacking vpu (Virology 293, 2002, 252). Sequence analysis revealed no reversion of the glycine residues in the vpu sequences isolated from this macaque. These results contrast with those from four macaques inoculated with the parental pathogenic SHIV(KU-1bMC33), all of which developed severe CD4(+) T cell loss within 1 month after inoculation. Taken together, these results indicate that casein kinase II phosphorylation sites of Vpu contributes to the pathogenicity of the SHIV(KU-1bMC33) and suggest that the SHIV(KU-1bMC33)/pig-tailed macaque model will be useful in analyzing amino acids/domains of Vpu that contribute to the pathogenesis of HIV-1. 相似文献
99.
Apoptotic cell death in mouse models of GM2 gangliosidosis and observations on human Tay-Sachs and Sandhoff diseases 总被引:5,自引:2,他引:5
Huang JQ; Trasler JM; Igdoura S; Michaud J; Hanal N; Gravel RA 《Human molecular genetics》1997,6(11):1879-1885
Tay-Sachs and Sandhoff diseases are autosomal recessive neurodegenerative
diseases resulting from the inability to catabolize GM2 ganglioside by
beta-hexosaminidase A (Hex A) due to mutations of the alpha subunit
(Tay-Sachs disease) or beta subunit (Sandhoff disease) of Hex A. Hex B
(beta beta homodimer) is also defective in Sandhoff disease. We previously
developed mouse models of both diseases and showed that Hexa-/- (Tay-Sachs)
mice remain asymptomatic to at least 1 year of age while Hexb-/- (Sandhoff)
mice succumb to a profound neurodegenerative disease by 4-6 months of age.
Here we find that neuron death in Hexb-/- mice is associated with apoptosis
occurring throughout the CNS, while Hexa-/- mice were minimally involved at
the same age. Studies of autopsy samples of brain and spinal cord from
human Tay-Sachs and Sandhoff diseases revealed apoptosis in both instances,
in keeping with the severe expression of both diseases. We suggest that
neuron death is caused by unscheduled apoptosis, implicating accumulated
GM2 ganglioside or a derivative in triggering of the apoptotic cascade.
相似文献
100.
The bias favoring deletion over inversion in DH-JH rearrangement has been
known for years, but the underlying mechanism has yet to be fully defined.
It has been suggested that the ratio of deletion/inversion is determined by
the combined effect of two factors: (i) the relative strengths of 5' and 3'
recombination signal sequences (RSS) of a DH segment, and (ii) the
efficiency with which the deletional product (one joint) forms relative to
the inversional product (two joints). In this study, we analyzed for the
first time the effect of factor 1 alone on the biased 3' RSS utilization in
DH-JH joining by using deletional plasmids in an extrachromosomal substrate
V(D)J recombination assay. It was found that the 3' RSS and associated
coding end (12 bp) mediate recombination more efficiently than the 5'
RSS/coding end DH-JH plasmids. These results demonstrate that the effect of
the RSS/coding end alone can account, at least partially, for the
predominant deletion in DH-JH recombination. The potential effect of the
relative strength of RSS and associated coding end on the ordered
rearrangement of DH-JH followed by VH to DH-JH was also assessed. When
recombination frequencies of D-->J (3' DH to J3) were compared with
frequencies of V-- >D (VHPJ14 to 3' DH or VHOX2 to 3' DH), it was found
that V-->D joining was, if anything, more efficient than D-->J
joining. Therefore, if all three segments were accessible, RSS/coding end
effects would not contribute to the ordered rearrangement of the IgH locus.
相似文献