全文获取类型
收费全文 | 5396篇 |
免费 | 385篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 118篇 |
妇产科学 | 199篇 |
基础医学 | 667篇 |
口腔科学 | 158篇 |
临床医学 | 580篇 |
内科学 | 1294篇 |
皮肤病学 | 83篇 |
神经病学 | 328篇 |
特种医学 | 347篇 |
外科学 | 692篇 |
综合类 | 131篇 |
预防医学 | 189篇 |
眼科学 | 155篇 |
药学 | 386篇 |
中国医学 | 44篇 |
肿瘤学 | 399篇 |
出版年
2023年 | 22篇 |
2022年 | 65篇 |
2021年 | 110篇 |
2020年 | 72篇 |
2019年 | 89篇 |
2018年 | 143篇 |
2017年 | 103篇 |
2016年 | 123篇 |
2015年 | 235篇 |
2014年 | 206篇 |
2013年 | 233篇 |
2012年 | 387篇 |
2011年 | 372篇 |
2010年 | 228篇 |
2009年 | 161篇 |
2008年 | 282篇 |
2007年 | 286篇 |
2006年 | 268篇 |
2005年 | 248篇 |
2004年 | 240篇 |
2003年 | 296篇 |
2002年 | 260篇 |
2001年 | 193篇 |
2000年 | 167篇 |
1999年 | 127篇 |
1998年 | 56篇 |
1997年 | 38篇 |
1996年 | 39篇 |
1995年 | 29篇 |
1994年 | 26篇 |
1993年 | 34篇 |
1992年 | 93篇 |
1991年 | 70篇 |
1990年 | 63篇 |
1989年 | 57篇 |
1988年 | 55篇 |
1987年 | 58篇 |
1986年 | 49篇 |
1985年 | 28篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1979年 | 25篇 |
1978年 | 14篇 |
1977年 | 15篇 |
1974年 | 9篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有5828条查询结果,搜索用时 0 毫秒
1.
2.
Micro‐evolution of the hepatitis B virus genome in hepatitis B e‐antigen‐positive carriers: Comparison of genotypes B and C at various immune stages 下载免费PDF全文
3.
4.
Objective This study evaluated the Impact on Sibling scale, a six-item measure of parents' perception of the effects of a child's illness on healthy siblings.
Methods Participants were 122 parents of a child with chronic illness, developmental disability, or autism spectrum disorder, and a well sibling aged 4–13 years. Parents completed the Impact on Sibling scale and the Child Behavior Checklist about the sibling, and completed the revised Impact on Family scale and the Brief Symptom Inventory about themselves.
Results The Impact on Sibling score was correlated with measures of sibling, parent and family functioning. The internal consistency of the Impact on Sibling scale was higher for families with children with chronic illness compared with the other two diagnostic groups.
Conclusion The Impact on Sibling scale is a brief set of items that can help identify siblings who are negatively affected by a brother/sister's illness. Findings support further research on the Impact on Sibling scale, particularly with families of children with chronic illnesses. 相似文献
Methods Participants were 122 parents of a child with chronic illness, developmental disability, or autism spectrum disorder, and a well sibling aged 4–13 years. Parents completed the Impact on Sibling scale and the Child Behavior Checklist about the sibling, and completed the revised Impact on Family scale and the Brief Symptom Inventory about themselves.
Results The Impact on Sibling score was correlated with measures of sibling, parent and family functioning. The internal consistency of the Impact on Sibling scale was higher for families with children with chronic illness compared with the other two diagnostic groups.
Conclusion The Impact on Sibling scale is a brief set of items that can help identify siblings who are negatively affected by a brother/sister's illness. Findings support further research on the Impact on Sibling scale, particularly with families of children with chronic illnesses. 相似文献
5.
L R Kao C F Wilkinson 《Xenobiotica; the fate of foreign compounds in biological systems》1987,17(7):793-805
1. Inhibitory activity of dihydrosafrole towards benzo[a]pyrene (BP) hydroxylase activity in hepatic microsomes from beta-naphthoflavone (BNF)-induced rats, and in reconstituted systems containing cytochrome P-450c, increased dramatically on preincubation of the inhibitor with NADPH; no inhibition occurred without preincubation. The level of BP hydroxylase inhibition was associated with the progressive formation of the 456 nm dihydrosafrole metabolite-cytochrome P-450c spectral complex during preincubation. 2. Inhibition of BP hydroxylase by dihydrosafrole in control microsomes, and inhibition of ethoxyresorufin O-deethylase (EROD) in microsomes (control or BNF-induced) and in reconstituted systems with cytochrome P-450c, did not require preincubation and apparently was not dependent on prior formation of the dihydrosafrole metabolite-cytochrome P-450 complex. 3. Kinetic studies established that, following preincubation with NADPH, dihydrosafrole was a noncompetitive inhibitor of both BP hydroxylase and EROD activities. In the absence of preincubation, dihydrosafrole was an effective competitive inhibitor of EROD in BNF-induced microsomes and in reconstituted systems with cytochrome P-450c. 4. Both ethoxyresorufin and benzo[a]pyrene inhibited the development of the type I optical difference spectrum of dihydrosafrole in reconstituted systems containing cytochrome P-450c. Inhibition by ethoxyresorufin was competitive while that caused by benzo[a]pyrene was noncompetitive in nature. 5. The type II ligand phenylimidazole was an effective noncompetitive inhibitor of EROD activity but failed to exert any inhibitory effect on cytochrome P-450c-mediated BP hydroxylase activity. Phenylimidazole inhibited formation of the dihydrosafrole type I optical difference spectrum non-competitively. 6. The results indicate that ethoxyresorufin and benzo[a]pyrene may occupy different binding sites on cytochrome P-450c and that dihydrosafrole binds primarily to the site utilized by ethoxyresorufin. 相似文献
6.
Shah-Hwa Chou Eing-Long Kao Chien-Chih Lin Meei-Feng Huang 《Clinical autonomic research》2006,16(3):240-242
A total of 114 patients with various sympathetic disorders underwent endoscopic sympathetic block over different thoracic
ganglions by the clipping method. The advantages of this method include the recognition of the clipped level, changeability,
and reversibility. However, 4.4% of patients were unilaterally clipped at the wrong level. 相似文献
7.
8.
Chun-Hsiung Huang Fang-Yuan Ho Hon-Ming Ma Chan-Tsung Yang Jiann-Jong Liau Hung-Chan Kao Tai-Horng Young Cheng-Kung Cheng 《Journal of orthopaedic research》2002,20(5):1038-1041
Osteolysis induced by ultrahigh molecular weight polyethylene wear debris has been recognized as the major cause of long-term failure in total joint arthroplasties. In a previous study, the prevalence of intraoperatively identified osteolysis during primary revision surgery was much higher in mobile bearing knee replacements (47%) than in fixed bearing knee replacements (13%). We postulated that mobile bearing knee implants tend to produce smaller sized particles. In our current study, we compared the particle size and morphology of polyethylene wear debris between failed mobile bearing and fixed bearing knees. Tissue specimens from interfacial and lytic regions were extracted during revision surgery of 10 mobile bearing knees (all of the low contact stress (LCS) design) and 17 fixed bearing knees (10 of the porous-coated anatomic (PCA) and 7 of the Miller/Galante design). Polyethylene particles were isolated from the tissue specimens and examined using both scanning electron microscopy and light-scattering analyses. The LCS mobile bearing knees produced smaller particulate debris (mean equivalent spherical diameter: 0.58 microm in LCS, 1.17 microm in PCA and 5.23 microm in M/G) and more granular debris (mean value: 93% in LCS, 77% in PCA and 15% in M/G). 相似文献
9.
A general model is developed for segmenting magnetic resonance images using vector decomposition and probabilfty techniques. Each voxel is assigned fractional volumes of q tissues from p differently weighted images (q ≤ p + 1) in the presence of partial-volume mixing, random noise, and other tissues. Compared wtth the eigenimage method, fewer differently weighted images are needed for segmenting the q tissues, and the contrast-to-noise ratio in the calculated fractional volumes is improved. The model can produce com-posrte tissue-type images similar to that of the probability methods, by comparing the fractional volumes assigned to different tissues on each voxel. A three-tissue (p = 2, q = 3) model is illustrated for segmenting three tissues from dual-echo images. M provides statistical analysis to the algebraic method. A three-compartment phantom is segmented for validation. Two clinical examples are presented. 相似文献
10.
Barbara Porton Adriana Ferreira Lynn E DeLisi Hung Teh Kao 《Neuropsychopharmacology》2004,55(2):118-125
BACKGROUND: Synapsin III plays a role in neuronal plasticity and maps to chromosome 22q12-13, a region suggested to be linked to schizophrenia. To determine if synapsin III plays a role in this disease, we searched for polymorphisms in this gene in patients with schizophrenia and controls. METHODS: The synapsin III gene was initially sequenced from 10 individuals with schizophrenia to identify polymorphisms. Association analysis was then performed using 118 individuals with schizophrenia and 330 population controls. Synapsin III expression was studied by immunoblot analyses, and phosphorylation sites were mapped by sequencing trypsin-digested synapsin III fragments phosphorylated with phosphorus-32. RESULTS: A rare, missense polymorphism, S470N, was identified in the synapsin III gene and appeared more frequently in individuals with schizophrenia than in controls (p =.0048). The site affected by the polymorphism, Ser470, was determined to be a substrate for mitogen-activated protein kinase, a downstream effector of neurotrophin action. Phosphorylation at Ser470 was increased during neonatal development and in response to neurotrophin-3 in cultured hippocampal neurons. CONCLUSIONS: Our observations suggest an association of a rare polymorphism in synapsin III with schizophrenia, but further studies will be required to clarify its role in this disease. 相似文献