全文获取类型
收费全文 | 3922篇 |
免费 | 302篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 73篇 |
妇产科学 | 51篇 |
基础医学 | 576篇 |
口腔科学 | 59篇 |
临床医学 | 586篇 |
内科学 | 810篇 |
皮肤病学 | 59篇 |
神经病学 | 237篇 |
特种医学 | 124篇 |
外国民族医学 | 1篇 |
外科学 | 547篇 |
综合类 | 26篇 |
预防医学 | 336篇 |
眼科学 | 156篇 |
药学 | 285篇 |
中国医学 | 26篇 |
肿瘤学 | 256篇 |
出版年
2024年 | 5篇 |
2023年 | 47篇 |
2022年 | 117篇 |
2021年 | 248篇 |
2020年 | 133篇 |
2019年 | 128篇 |
2018年 | 126篇 |
2017年 | 107篇 |
2016年 | 108篇 |
2015年 | 116篇 |
2014年 | 129篇 |
2013年 | 172篇 |
2012年 | 268篇 |
2011年 | 274篇 |
2010年 | 139篇 |
2009年 | 143篇 |
2008年 | 240篇 |
2007年 | 247篇 |
2006年 | 207篇 |
2005年 | 184篇 |
2004年 | 168篇 |
2003年 | 131篇 |
2002年 | 106篇 |
2001年 | 101篇 |
2000年 | 91篇 |
1999年 | 81篇 |
1998年 | 25篇 |
1997年 | 36篇 |
1996年 | 22篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 41篇 |
1991年 | 27篇 |
1990年 | 22篇 |
1989年 | 49篇 |
1988年 | 15篇 |
1987年 | 28篇 |
1986年 | 16篇 |
1985年 | 23篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1974年 | 6篇 |
1972年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有4232条查询结果,搜索用时 0 毫秒
11.
12.
C Meyer-Bisch Q T Pham J M Mur N Massin J J Moulin D Teculescu B Carton F Pierre F Baruthio 《British journal of industrial medicine》1989,46(5):302-309
A cross sectional study was conducted on 513 employees at three hard metal plants: 425 exposed workers (351 men, 74 women) and 88 controls (69 men, 19 women). Cough and sputum were more frequent in workers engaged in "soft powder" and presintering workshops compared with controls (12.5% and 16.5% v 3.5%). Spirometric abnormalities were more frequent among women in sintering and finishing workshops compared with control women (56.8% v 23.8%) and abnormalities of carbon monoxide test were more frequent in exposed groups than in controls; this difference was more pronounced in women (31.4% v 5.6%) than in men (18.5% v 13%). No significant correlation was observed between duration of exposure and age adjusted lung function tests. Slight abnormalities of chest radiographs (0/1, 1/1 according to ILO classification) were more frequent in exposed men than controls (12.8% v 1.9%) and mostly in soft powder workers. In subjects with abnormal chest radiographs FVC, FEV1 and carbon monoxide indices (fractional uptake of CO or CO transfer index or both) were lower compared with those with normal chest radiographs. Although relatively mild, the clinical, radiological, and functional abnormalities uncovered call for a regular supervision of workers exposed to hard metal dust. 相似文献
13.
The biochemical characterization of E2, a T cell surface molecule involved in rosettes 总被引:3,自引:0,他引:3
We have previously identified a molecule on the T cell surface, which, in addition to CD2 is involved in the rosette phenomenon. This is a 32-kDa single polypeptide chain which we have termed E2. The studies reported here show striking patterns on the glycosylation status of E2. It is a heavily sialylated and glycosylated molecule, the sugar moieties accounting for almost half of its relative molecular mass (Mr). It carries no N-linked sugar residues, only O-linked oligosaccharides. Despite heavy glycosylation, the molecule appears to behave homogeneously on gel electrophoresis, both in terms of Mr and pI. Neuraminidase treatment of E2 lowered its Mr to 28 kDa; this was further decreased to 18 kDa after removal of O-linked sugar residues by treatment with O-glycanase. An identical reduction in size was observed after treatment with trifluoromethane sulfonic acid, showing that the molecule carries no detectable N-linked sugar residues. Moreover, endoglycosidase F and endoglycosidase H treatment of either the immunoprecipitates from 125I surface-labeled thymocytes, or of a purified preparation of E2, did not reduce the Mr of E2, nor did tunicamycin treatment of T cells. Two-dimensional gel electrophoresis revealed two discrete spots of acidic pI (4.4 and 4.6) that were still seen after neuraminidase treatment, though they had moderately shifted. Pulse-chase experiments revealed a single 28-kDa precursor form that could have been the unsialylated molecule. Finally, sequencing 14 amino acid residues of the N-terminal side revealed no homology with known proteins. Since the sugar moieties of adhesion protein could play an important role, the results obtained in this study will prove valuable to our understanding of the role exerted by the E2 molecule. 相似文献
14.
CD4+/CD8+ ratio of liver-derived lymphocytes is related to viraemia and not to hepatitis C virus genotypes in chronic hepatitis C. 下载免费PDF全文
B N Pham M Martinot-Peignoux J F Mosnier C Njapoum P Marcellin F Bougy C Degott S Erlinger J H Cohen F Degos 《Clinical and experimental immunology》1995,102(2):320-327
The pathogenic mechanisms that lead to chronic hepatitis C are unknown. As hepatitis C virus (HCV) has been shown to induce T cell response, we assessed whether a particular T lymphocyte subset could be preferentially detected in the liver of patients with chronic hepatitis C in relation to viraemia or HCV genotypes. The immunophenotypes of liver-derived lymphocytes were analysed in 26 patients by flow cytometry and immunohistochemistry. Viraemia was quantified by branched DNA assay. Using this assay, HCV RNA was not detectable in six patients. HCV RNA was detected in 20 patients, and titres ranged from 8 to 137 x 10(6) Eq/ml. Genotyping was performed using a line probe assay. Type 1a, 1b, 2a, 3a and 4a were found to infect 2, 10, 2, 7 and 3 patients, respectively. The CD4+/CD8+ ratio of liver-derived lymphocytes was significantly higher (P < 0.01) in patients with detectable viraemia than in patients without detectable viraemia. In contrast, neither the percentage of gamma/delta T lymphocytes nor that of CD2+CD57+ cells was different in the groups. When comparing the CD4+/CD8+ ratio, the percentage of gamma/delta T lymphocytes or CD2+CD57+ cells according to genotype, the differences were not significant. These results suggest that the CD4+/CD8+ ratio of liver-derived lymphocytes is related to viraemia but not to HCV genotypes in patients with chronic hepatitis C, and that T lymphocytes may be involved in the pathogenesis of liver lesions in chronic hepatitis C. 相似文献
15.
Han XY Pham AS Nguyen KU Smythe WR Ordonez NG Jacobson KL Tarrand JJ 《American journal of clinical pathology》2001,116(3):347-353
Pulmonary granuloma is a common lesion for which gram-negative bacteria are rarely implicated as a cause. Hence, most physicians are unaware of this etiology. We isolated a gram-negative bacterium from a surgically resected pulmonary granuloma in a 42-year-old, nonimmunocompromised woman. Within the necrotizing granuloma, numerous organisms also were demonstrated by Gram stain, suggesting a cause-disease relationship. Characterization of the bacterium by sequence analysis of the 16S ribosomal gene, cellular fatty acid profiling, and microbiologic studies revealed a novel bacterium with a close relationship to Pseudomonas. We propose a new species for the bacterium, Pseudomonas andersonii. These results suggest that the differential diagnosis of a lung granuloma also should include this gram-negative bacterium as a potential causative agent, in addition to the more common infections caused by acid-fast bacilli and fungi. This bacterium was shown to be susceptible to most antibiotics that are active against gram-negative bacteria. 相似文献
16.
Dien Pham Huy Monique Roch-Arveiller Monique Lenoir Olivier Muntaner Alain Thuret Jean-Paul Giroud 《Inflammation research》1986,18(3-4):366-371
The effect of piroxicam on rat polymorphonuclear leucocytes (PMN) has been studiedin vitro andin vivo after the induction of two acute, non specific inflammatory reactions (pleurisies induced by calcium pyrophosphate crystals (CaPP) or isologous serum).An inhibition of chemotaxis by piroxicam has been demonstrated by two techniques, the filter and agarose assaysin vivo andin vitro. An inhibition of random cell migration has been observed only at the higher drug concentration using agarose assay with CaPP-elicited cells.Piroxicam also inhibited superoxide anion generation and O2 consumption of CaPP- and serum-elicited cells.These findings suggest that piroxicam may have a direct effect on PMN responses and that this activity could, at least in part, contribute to its anti-inflammatory properties. 相似文献
17.
Pham MT Maitz MF Reuther H Muecklich A Prokert F Steiner G 《Journal of biomedical materials research. Part A》2004,71(1):16-24
The native extracellular matrix (ECM) laid down on silicon and titanium surfaces by osteoblast-like SAOS-2 cells was exposed by selective removal of cells. This type of material surface ECM-Si, ECM-Ti was shown to promote the nucleation of calcium phosphate from a simulated body fluid (SBF). Microscopic and spectroscopic results revealed the effect was associated with a collagen fiber-free extracellular matrix. 相似文献
18.
Myotonic dystrophy (DM) is a multisystemic disorder caused by an inherited CTG repeat expansion which affects three genes encoding the DM protein kinase (DMPK), a homeobox protein Six5 and a protein containing WD repeats. Using a panel of 16 monoclonal antibodies against several different DMPK epitopes we detected DMPK, as a single protein of approximately 80 kDa, only in skeletal muscle, cardiac muscle and, to a lesser extent, smooth muscle. Many earlier reports of DMPK with different sizes and tissue distributions appear to be due to antibody cross-reactions with more abundant proteins. One such antibody, MANDM1, was used to isolate two related protein kinases, MRCK alpha and beta, from a human brain cDNA library and the shared epitope was located at the catalytic site of DMPK using a phage-displayed random peptide library. The peptide library also identified an epitope shared between DMPK and a 55 kDa muscle-specific protein. The results suggest that effects of the repeat expansion on the DMPK gene may be responsible for muscle and heart features of DM, whereas clinical changes in other tissues may be due to effects on the other two genes. 相似文献
19.
The examination of H2O2-initiated hydroxytelechelic polybutadienes polymerized by H2O2 initiation by 1H NMR and 13C NMR allows the identification of three main primary alcoholic groups: α-unsaturated, β-substituted/α-unsaturated and γ-unsaturated. From 1H NMR accumulated spectra, it has been possible to calculate the number average OH-functionalities of the polymers. These should be slightly under-estimated because of the possible presence of secondary and tertiary alcoholic groups whose concentrations, however, should be very small. The nature of these alcohol functions gives information concerning the likely initiation, transfer and termination mechanisms of the radical polymerization of butadiene by H2O2 in alcoholic media. 相似文献
20.
Pham HM Konnai S Usui T Chang KS Murata S Mase M Ohashi K Onuma M 《Archives of virology》2005,150(12):2429-2438
Summary. In order to rapidly detect and differentiate Newcastle disease virus (NDV) isolates, a method based on real-time PCR SYBR
Green I melting-curve analysis of the fusion (F) protein gene was developed. The detection limit of real-time PCR was 9 × 102 plasmid copies and was 100 times more sensitive than conventional PCR. Thirty eight reference NDV strains were rapidly identified
by their distinctive melting temperatures (Tms): 89.23 ± 0.27 °C for velogenic strains, 90.17 ± 0.35 °C for pigeon mesogenic strains, 91.25 ± 0.14 °C for two lentogenic
strains (B1 and Ishii). No amplification was detected from unrelated RNA samples by this method. This real-time PCR directly
detected NDV from infected tissues and eliminated the gel electrophoretic step for analyzing PCR product using ethidium bromide.
The total time for a PCR run was less than 1 hour. The results obtained in this study showed that the real-time PCR presented
here is a good screening test for the identification of NDV. 相似文献