全文获取类型
收费全文 | 793篇 |
免费 | 5篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 27篇 |
妇产科学 | 7篇 |
基础医学 | 93篇 |
口腔科学 | 32篇 |
临床医学 | 55篇 |
内科学 | 158篇 |
皮肤病学 | 19篇 |
神经病学 | 85篇 |
特种医学 | 47篇 |
外科学 | 91篇 |
综合类 | 17篇 |
预防医学 | 46篇 |
眼科学 | 26篇 |
药学 | 66篇 |
中国医学 | 13篇 |
肿瘤学 | 9篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 110篇 |
2018年 | 107篇 |
2017年 | 51篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 41篇 |
2013年 | 21篇 |
2012年 | 36篇 |
2011年 | 49篇 |
2010年 | 25篇 |
2009年 | 21篇 |
2008年 | 24篇 |
2007年 | 15篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 26篇 |
1984年 | 39篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1979年 | 16篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 3篇 |
排序方式: 共有798条查询结果,搜索用时 31 毫秒
1.
The instability of membrane markers expressed by human monocytes and macrophages in culture 总被引:2,自引:0,他引:2
Surface markers were tested on freshly isolated human monocytes and following their in vitro maturation to macrophages. The markers tested were HLA-DR antigens, receptors for the Fc of IgG and complement as well as membrane markers defined by monoclonal antibodies. The results revealed a dynamic expression of some of the markers on monocytes which was influenced by several variables. The expression of the markers was modulated by the presence of different sera, by treatment with lymphokines and interferon and following the in vitro maturation of monocytes to macrophages. The most unstable marker was found to be the HLA-DR, which was modulated by all these variables. The 63D3 was affected by different sera and culture supernatant, as well as following the maturation of monocytes to macrophages, but not by lymphokines and interferon. One of the markers, the Mac 120, was found to be relatively stable and did not change significantly following the maturation of monocytes to macrophages. The Fc and complement receptors were also stable in their expression under these conditions, but were probably partially blocked in the presence of human serum. These results indicated that at least some of the heterogeneity related to the monocyte population was probably not due to the occurrence of stable subsets of cells, but rather to reversible changes in marker expression. 相似文献
2.
Kazuya Takeda Shuhei Sakakibara Kazuo Yamashita Daisuke Motooka Shota Nakamura Marwa Ali El Hussien Jun Katayama Yohei Maeda Masanobu Nakata Shigeyuki Hamada Daron M. Standley Masaki Hayama Takashi Shikina Hidenori Inohara Hitoshi Kikutani 《The Journal of allergy and clinical immunology》2019,143(3):1163-1175.e15
3.
The molecular nature of the membrane antigen that is acquired from FCS-containing media by human lymphoblastoid cells has been investigated. The presence of bovine α2, macroglobulin on the surface of Namalva cells was demonstrated by radioimmunoassay using specific antisera. Alternatively, cell-bound bovine α2,M could be detected by the more sensitive heterophile rosette assay described previously. Namalva cells grown in NHS-containing media acquired bovine α2 M upon subsequent incubation with the purified protein in a dose- and time-dependent way. Acquisition of α2 M was demonstrated using both viable and formaldehyde-fixed cells. Purified fetuin, which carries a heterophile epitope shared with bovine α2 M as well as with other glycoproteins, failed to bind with the membrane of Namalva cells. The possible role of acquired α2 macroglobulin on cells has been discussed. 相似文献
4.
目的:探讨原发性肝癌(HCC)患者治疗前,后的血清可溶性上皮钙粘蛋白(SE-Cadherin)水平变化,方法:用酶联免疫吸附双抗体夹心法检测26例HCC患者治疗前,后的血清SE-Cadherin水平及21例正常健康人血清SE-Cadherin水平。结果:原发性肝癌患者治疗前血清SE-Cadherin水平明显高于治疗后,其差异有显著性意义(P<0.01),而正常健康人血清SE-Cadherin水平不高,结论:血清SE-Cadherin 水平的测定可作为原发性肝癌的诊断及疗效观察指标,并有可能成为预后评判和复发指标。 相似文献
5.
6.
We quantified the decline in COPD risk following quitting using the negative exponential model, as previously carried out for other smoking-related diseases. We identified 14 blocks of RRs (from 11 studies) comparing current smokers, former smokers (by time quit) and never smokers, some studies providing sex-specific blocks. Corresponding pseudo-numbers of cases and controls/at risk formed the data for model-fitting. We estimated the half-life (H, time since quit when the excess risk becomes half that for a continuing smoker) for each block, except for one where no decline with quitting was evident, and H was not estimable. For the remaining 13 blocks, goodness-of-fit to the model was generally adequate, the combined estimate of H being 13.32 (95% CI 11.86–14.96) years. There was no heterogeneity in H, overall or by various studied sources. Sensitivity analyses allowing for reverse causation or different assumed times for the final quitting period little affected the results. The model summarizes quitting data well. The estimate of 13.32 years is substantially larger than recent estimates of 4.40 years for ischaemic heart disease and 4.78 years for stroke, and also larger than the 9.93 years for lung cancer. Heterogeneity was unimportant for COPD, unlike for the other three diseases. 相似文献
7.
Giorgia Del Favero Silvio Sosa Mark Poli Aurelia Tubaro Orfeo Sbaizero Paola Lorenzon 《Toxicology letters》2014
Palytoxins (PLTXs) are known seafood contaminants and their entrance into the food chain raises concern about possible effects on human health. The increasing number of analogs being identified in edible marine organisms complicates the estimation of the real hazard associated with the presence of PLTX-like compounds. So far, 42-OH-PLTX is one of the few congeners available, and the study of its toxicity represents an important step toward a better comprehension of the mechanism of action of this family of compounds. From this perspective, the aim of this work was to investigate the in vivo and in vitro effect of 42-OH-PLTX on skeletal muscle, one of the most sensitive targets for PLTXs. Our results demonstrate that 42-OH-PLTX causes damage at the skeletal muscle level with a cytotoxic potency similar to that of PLTX. 42-OH-PLTX induces cytotoxicity and cell swelling in a Na+-dependent manner similar to the parent compound. However, the limited Ca2+-dependence of the toxic insult induced by 42-OH-PLTX suggests a specific mechanism of action for this analog. Our results also suggest an impaired response to the physiological agonist acetylcholine and altered cell elasticity. 相似文献
8.
Ravil Sharifulin Alexander Bogachev-Prokophiev Sergey Zheleznev Igor Demin Alexey Pivkin Alexander Afanasyev Alexander Karaskov 《The Journal of thoracic and cardiovascular surgery》2019,157(1):134-141.e3
Objective
Although the Ross procedure provides excellent long-term survival and a high quality of life, its use has been limited to relatively few centers. In this study, we evaluated long-term Ross procedure results in adults to assess the predictors of pulmonary autograft durability.Methods
Between 1998 and 2015, 793 consecutive adult patients underwent the Ross procedure. The total root replacement technique was used in all patients.Results
The early mortality rate was 2.9%. The mean follow-up duration was 6.5 ± 3.2 years, and the 10-year survival rate was 90.4%. Longitudinal mixed-effects ordinal regression identified a combination of bicuspid aortic valve and aortic insufficiency (odds ratio, 2.19; P < .001) as predictors for progression of autograft valve insufficiency at follow-up. The cumulative incidence of autograft reoperations at 10 years was 8.6%. Competing risk regression identified bicuspid aortic valve insufficiency as the independent predictor of autograft reoperation (subdistribution hazard ratio, 2.16; P = .030). Moreover, patients with bicuspid aortic valve and aortic insufficiency had greater increases in annulus (P < .001), sinus (P < .001), and ascending aorta (P < .001) diameters over time.Conclusions
For patients undergoing the Ross procedure, a combination of bicuspid aortic valves and aortic insufficiency is the main risk factor for late autograft dilatation and dysfunction. 相似文献9.
10.