全文获取类型
收费全文 | 53033篇 |
免费 | 5815篇 |
国内免费 | 4221篇 |
专业分类
耳鼻咽喉 | 448篇 |
儿科学 | 760篇 |
妇产科学 | 597篇 |
基础医学 | 5538篇 |
口腔科学 | 993篇 |
临床医学 | 6950篇 |
内科学 | 7345篇 |
皮肤病学 | 371篇 |
神经病学 | 2530篇 |
特种医学 | 1837篇 |
外国民族医学 | 33篇 |
外科学 | 4917篇 |
综合类 | 10633篇 |
现状与发展 | 18篇 |
一般理论 | 2篇 |
预防医学 | 4188篇 |
眼科学 | 1333篇 |
药学 | 6079篇 |
70篇 | |
中国医学 | 3935篇 |
肿瘤学 | 4492篇 |
出版年
2024年 | 259篇 |
2023年 | 1017篇 |
2022年 | 2475篇 |
2021年 | 3104篇 |
2020年 | 2376篇 |
2019年 | 1989篇 |
2018年 | 1965篇 |
2017年 | 1962篇 |
2016年 | 1779篇 |
2015年 | 2756篇 |
2014年 | 3162篇 |
2013年 | 2966篇 |
2012年 | 4341篇 |
2011年 | 4558篇 |
2010年 | 3151篇 |
2009年 | 2718篇 |
2008年 | 3021篇 |
2007年 | 2768篇 |
2006年 | 2626篇 |
2005年 | 2350篇 |
2004年 | 1692篇 |
2003年 | 1608篇 |
2002年 | 1341篇 |
2001年 | 1135篇 |
2000年 | 1032篇 |
1999年 | 982篇 |
1998年 | 580篇 |
1997年 | 542篇 |
1996年 | 445篇 |
1995年 | 440篇 |
1994年 | 347篇 |
1993年 | 209篇 |
1992年 | 255篇 |
1991年 | 221篇 |
1990年 | 171篇 |
1989年 | 140篇 |
1988年 | 151篇 |
1987年 | 120篇 |
1986年 | 87篇 |
1985年 | 70篇 |
1984年 | 33篇 |
1983年 | 30篇 |
1982年 | 20篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 15篇 |
1978年 | 9篇 |
1972年 | 3篇 |
1970年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
We cloned the heavy- and light-chain variable domains of two monoclonal antibodies that recognize each of the two major neutralizing antigenic sites of the canine parvovirus (CPV) capsid. After expression in Escherichia coli as single-chain variable domains (scFv) with glycine-serine linker sequences, both scFv bound CPV capsids with the same specificity as the intact IgG, but with 10- to 20-fold lower avidity. Both scFvs neutralized CPV infectivity with efficiency similar to that of the IgG. Although both IgGs inhibited hemagglutination by CPV, only one scFv was inhibiting. The binding of one of the antibodies has previously been analyzed by cryoelectron microscopic reconstruction and the epitope-binding residues predicted. Mutagenesis of predicted contact residues in three heavy-chain complementarity-determining regions (CDR) showed that mutants of CDR1 or CDR3 reduced the binding of the scFv by about 10-fold compared with the wild-type scFv, while no effect was seen for one mutant of CDR2. The levels of neutralization of CPV and of hemagglutination inhibition by the scFv mutants were proportional to their reduction in binding affinity compared with the wild type. Neither scFv blocked virus binding to host cells, but they both caused aggregation of the capsids and appeared to affect the process of infection after virus uptake into the cells. 相似文献
52.
In this study, a human adult testis cDNA microarray was constructed and hybridized with (33)P-labeled human adult testis, embryo testis and sperm cDNA probes, respectively. A novel alternative splice variant of BRDT gene, named BRDT-NY, presumably involved in testicular function was cloned. It was expressed 3.96-fold more in human adult than embryo testis and also expressed in human spermatozoa. Similarly, RT-PCR revealed a differential expression pattern of this gene in human adult testes and fetal testes. The full length of BRDT-NY was 3438 bp and contained a 2883 bp open reading frame, encoding a 960-amino-acid protein. Sequence analysis showed that it has two bromodomains in N-terminal of the protein. Multiple tissue RT-PCR results showed that BRDT-NY was exclusively expressed in testis. mRNA expression of BRDT-NY gene was deleted in some azoospermic patients' testes. These experiments suggested that BRDT-NY gene may have an important role in the process of spermatogenesis and may be correlated with male infertility. 相似文献
53.
以傅立叶频谱滤波为手段的振荡电位波形分离方法 总被引:1,自引:0,他引:1
为克服传统方法(Calliper-square)和带通放大器在测量振荡电位(OPs)中的不足,应用计算机傅立叶频谱滤波技术,从ERG中分离出振荡电位波形。分离出的OPs能够摆脱a-波,b-波对它的影响而独立地表现出来,使得对OPs的测量变得直观、方便、准确,并把对ERG、OPs的研究,从时域分析扩展到频域分析。 相似文献
54.
Yanping Tang Ying Wang Ping Yang Yuan Liu Bo Wang Robert Podolsky Richard McIndoe Cong-Yi Wang 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(3):242-244
The prevalence of juvenile-onset Huntington's disease (HD) is about ten times lower than adult HD. Here we report a Chinese HD family showing both intergeneration CAG expansion and contraction. The expansion resulted from a paternal transmission which leads to juvenile-onset HD for a 17-year-old Chinese boy (III-5). More interestingly, a contraction was noticed in a maternal transmission (III-3), which changed the CAG repeat from an expanded, disease-causing allele (48 repeats) to a normal or intermediate allele (34 repeats). Of note, the contraction resulted in a deletion of 14 CAG repeats, which is much larger than previously reported contractions. Our results are consistent with previous observations in Western Caucasians that juvenile-onset HD is more likely inherited through the male germline. 相似文献
55.
Lin Hui Eun-Seok Shin Eun Jung Jun Youngjune Bhak Scot Garg Tae-Hyun Kim Chang-Bae Sohn Byung Joo Choi Liu Kun Song Lin Yuan Wang Zhi Jiang Hao Shi Zhentao Tang Qiang 《Yonsei medical journal》2020,61(12):1004
PurposeDissection after plain balloon angioplasty is required to achieve adequate luminal area; however, it is associated with a high risk of vascular events. This study aimed to examine the relationship between non-flow limiting coronary dissections and subsequent lumen loss and long-term clinical outcomes following successful drug-coated balloon (DCB) treatment of de novo coronary lesions.Materials and MethodsA total of 227 patients with good distal flow (Thrombolysis in Myocardial Infarction flow grade 3) following DCB treatment were retrospectively enrolled and stratified according to the presence or absence of a non-flow limiting dissection. The primary endpoint was late lumen loss (LLL) at 6-month angiography, and the secondary endpoint was target vessel failure (TVF, a composite of cardiac death, target vessel myocardial infarction, target vessel revascularization, and target vessel thrombosis).ResultsThe cohort consisted of 95 patients with and 132 patients without a dissection. There were no between-group differences in LLL (90.8%) returning for angiography at 6 months (0.05±0.19 mm in non-dissection and 0.05±0.30 mm in dissection group, p=0.886) or in TVF (6.8% in non-dissection and 8.4% in dissection group, p=0.799) at a median follow-up of 3.4 years. In a multivariate analysis, the presence of dissection and its severity were not associated with LLL or TVF. Almost dissections (93.9%) were completely healed, and there was no newly developed dissection at 6-month angiography.ConclusionThe presence of a dissection following successful DCB treatment of a de novo coronary lesion may not be associated with an increased risk of LLL or TVF (Impact of Drug-coated Balloon Treatment in de Novo Coronary Lesion; ). NCT04619277相似文献
56.
Wang Min Huang Cheng Shen Xin Zhang Yangyi Zhang Zurong Li Jing Zhao Genming Pan Qichao Jiang Yuan 《Zeitschrift fur Gesundheitswissenschaften》2022,30(5):1055-1062
Journal of Public Health - To investigate the attack rate of active tuberculosis (TB) cases and detection rate of latent tuberculosis infection (LTBI) cases, and to identify possible factors... 相似文献
57.
糖尿病患者膳食营养分析 总被引:5,自引:0,他引:5
目的 :探讨糖尿病患者膳食营养状况 ,提出改善糖尿病患者膳食结构的策略。方法 :对 2 2 5例糖尿病患者连续调查 3天膳食供给情况 ,建立数据库输入计算机 ,用SPSS软件进行分析。结果 :热能摄入量不符合要求者占77 3% ;蛋白质供给量不足者占患者总数的 75 6% ;47 6%的糖尿病患者脂肪摄入量超过标准 ;5 5 1%的糖尿病患者碳水化合物的摄入量不符合要求 ;膳食纤维摄入不足者占患者总数的 94 2 % ;维生素和无机盐中 ,除铁、核黄素和抗坏血酸供给量尚可 ,其余均不足。结论 :糖尿病患者膳食是不合理的 ,必须按照膳食治疗方案调节膳食 相似文献
58.
目的验证JOA X-线骨质疏松诊断标准的可靠性.方法47名女性病人(年龄65.3±7.2岁)行腰椎常规X-线检查和第三腰椎正、侧位DEXA骨密度测量.用t检验验证X-线骨质疏松等级间骨密度的差异性,用Spearman相关性分析法检验X-线骨质疏松等级与骨密度值的相关性.结果X-线骨质疏松等级间骨密度具有显著性差异(P<0.01),X-线骨质疏松等级与第三腰椎侧位骨密度值之间相关性最高(r=0.714).结论通过腰椎X-线片按照JOA标准划分骨质疏松等级,可以作为粗略检查腰椎骨质疏松的方法. 相似文献
59.
①目的探讨西沙比利对功能性消化不良病人胃肠激素影响.②方法采用放射免疫法测定98例功能性消化不良病人西沙比利治疗前后血浆胃动素、促胃液素、血管活性肠肽和生长抑素水平.③结果西沙比利可使功能性消化不良病人临床症状明显改善(x2=20.22,10.10,P<0.01),同时血浆中胃动素由(85.2士13.7)pmol/L升高至(131.5±15.6)pmol/L,差异有显著性(t=22.08,P<0.01).④结论西沙比利可明显改善功能性消化不良病人的临床症状,同时升高血浆中胃动素水平. 相似文献
60.
恩丹西酮预防椎管内阻滞后寒战的效果 总被引:7,自引:0,他引:7
①目的观察麻醉前静脉注射恩丹西酮预防椎管内阻滞后寒战的效果和对腋温的影响.②方法选择腰麻-硬膜外联合麻醉下行经腹全子宫切除术病人160例,随机分为两组,实验组(n=80)麻醉前静脉注射恩丹西酮8mg;对照组(n=80)麻醉前静脉注射生理盐水4mL,观察两组术中平均动脉压、心率、腋温变化和寒战发生情况.③结果实验组8例出现寒战(10.0%),对照组26例出现寒战(32.5%),两组比较差异有显著性(x2=7.05,P<0.01).两组平均动脉压、心率、腋温变化差异无显著性(t=0.14~1.71,P均>0.05).④结论恩丹西酮可预防椎管内阻滞后寒战的发生,但对腋温无影响. 相似文献