全文获取类型
收费全文 | 2365篇 |
免费 | 126篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 50篇 |
妇产科学 | 90篇 |
基础医学 | 417篇 |
口腔科学 | 48篇 |
临床医学 | 192篇 |
内科学 | 648篇 |
皮肤病学 | 60篇 |
神经病学 | 160篇 |
特种医学 | 31篇 |
外科学 | 272篇 |
综合类 | 10篇 |
预防医学 | 111篇 |
眼科学 | 67篇 |
药学 | 186篇 |
中国医学 | 7篇 |
肿瘤学 | 82篇 |
出版年
2023年 | 19篇 |
2022年 | 66篇 |
2021年 | 152篇 |
2020年 | 50篇 |
2019年 | 55篇 |
2018年 | 71篇 |
2017年 | 61篇 |
2016年 | 58篇 |
2015年 | 58篇 |
2014年 | 90篇 |
2013年 | 105篇 |
2012年 | 187篇 |
2011年 | 188篇 |
2010年 | 102篇 |
2009年 | 66篇 |
2008年 | 149篇 |
2007年 | 175篇 |
2006年 | 147篇 |
2005年 | 134篇 |
2004年 | 116篇 |
2003年 | 138篇 |
2002年 | 103篇 |
2001年 | 14篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1938年 | 3篇 |
1933年 | 5篇 |
1932年 | 5篇 |
1929年 | 4篇 |
1928年 | 4篇 |
1926年 | 7篇 |
1922年 | 3篇 |
1914年 | 3篇 |
1913年 | 7篇 |
1912年 | 6篇 |
1910年 | 3篇 |
1908年 | 4篇 |
排序方式: 共有2501条查询结果,搜索用时 0 毫秒
1.
2.
Francisco Airton Castro da Rocha Artur José de Brum-Fernandes 《Journal of bone and mineral research》2002,17(3):434-442
Peroxynitrite (PN), a nitric oxide (NO*)-derived anion, has been associated with NO* damage in various cell types. We examined the effects of adding PN to cultured human osteoblast-like (hOB) cells obtained after hip arthroplasty. Exposure to PN (0.1-0.4 mM) decreased both hOB proliferation and differentiation, measured by [3H]thymidine uptake and alkaline phosphatase production, respectively. Incubation with 3-morpholinosydnonimine (SIN-1; 0.25-1 mM), an NO* and O2- donor that leads to PN release, also reduced both hOB proliferation and differentiation. Coincubation with both superoxide dismutase (SOD; 100 U/ml) and catalase (CAT; 50 U/ml), rendering SIN-1 a pure NO* donor, reversed its effects on hOB proliferation and differentiation. However, SIN-1-induced NO* production, measured by nitrite release to the hOB medium, was not altered by cotreatment with SOD and CAT. Expression of nitrotyrosine by hOB, a marker of PN action, was significantly increased after SIN-1 addition, as compared with untreated cells, as revealed by Western blot analysis. Interleukin-1alpha (IL-1alpha) and interferon gamma (IFN-gamma) but not tumor necrosis factor alpha (TNF-alpha) also significantly increased nitrotyrosine expression in these cells. These data show that PN is at least partially responsible for osteoblast derangement by NO* and that cytokines released during inflammatory arthropathies can induce PN production in hOB cells. 相似文献
3.
4.
Differential effects of estradiol, raloxifene and tamoxifen on estrogen receptor expression in cultured human skin fibroblasts 总被引:2,自引:0,他引:2
5.
6.
7.
Mrio N. D. Peto Artur P. guas Carlos M. De S Nuno Rodrigues Grande 《Anatomical record (Hoboken, N.J. : 2007)》1995,241(3):383-390
Background: A peculiar feature of lung circulation in the lung is the pronounced variations in blood volume observed in alveolar capillaries that occur because of the changes in the conformation of the alveolar wall that are associated with the respiratory movements. This phenomenon has led to the postulate that mechanisms of postcapillary control of blood flow are to be present in the lung vessels. In the present study we searched for microanatomical evidence of vascular sphincters in the deep lung tissue of mice, namely in alveolar capillaries and pulmonary veins. Methods: We have used scanning electron microscopy (SEM) to examine two types of samples of normal lung tissue of CD-1 mice: 1) vascular corrosion casts made by vascular perfusion with Mercox® resin, and 2) routinely made gold/platinum-coated replicas of sectioned lung tissue. Results: Careful scrutiny of the vessels of the deep lung tissue led to the identification of sphincters in alveolar capillaries. These sphincters were located at the junction between capillary and pulmonary veins. They corresponded to areas to the vascular wall showing circular swellings where a radial organization was observed, since they were made up of alternating grooves and bulges. Transmission electron microscopy showed that smooth muscle cells participated in the formation of the sphincters. Conclusions: Our data reveal a new location for vascular sphincters in pulmonary vessels and, because these novel sphincters are located at the capillary-vein junction, they offer a structural setting for the existence of postcapillary control of blood flow in the pulmonary circulation of mice. © 1995 Wiley-Liss, Inc. 相似文献
8.
Vrolijk JM Kaul A Hansen BE Lohmann V Haagmans BL Schalm SW Bartenschlager R 《Journal of virological methods》2003,110(2):201-209
Overall treatment results of chronic hepatitis C have improved markedly with the introduction of pegylated interferon-alpha (PEG–IFN-) and ribavirin combination therapy. However, cure rates in the most common genotype 1 infection are still unsatisfactory. IFN- dose–response studies on viral kinetics suggest that inadequate dosing might be a key factor but drug levels have hardly been tested, which is in part due to difficulties in measuring this cytokine in patient samples. We have shown recently that hepatitis C virus (HCV) replicons are highly sensitive to IFN-. In this report we tested whether the replicon system could be used as a sensitive bioassay to determine the amount of biologically active IFN- in serum or heparinized plasma of patients under therapy. To facilitate the measurements, a stably replicating subgenomic HCV RNA was developed that carries the gene encoding the firefly luciferase. Dose response studies with IFN- demonstrate that the amount of expressed luciferase directly correlates with the level of HCV replication. By using this cell-based assay, serum samples of HCV patients treated with different types and doses of IFN- were analyzed in parallel to IFN- standards made by serial dilutions of the same type of IFN- the patient was treated with. Based on nonlinear logistic models serum concentrations corresponding to 1.3–19 U/ml were determined in patients under standard or high dose IFN- therapy, and from 3.8 to 4.1 ng/ml in patients treated with PEG IFN-. In conclusion, the HCV-replicon based bioassay allows determining the levels of biologically active IFN- in serum and heparinized plasma of patients under treatment. 相似文献
9.
Human heat shock protein 60 (409-424) fragment is recognized by serum antibodies of patients with acute coronary syndromes. 总被引:7,自引:0,他引:7
Jan Wysocki Bozena Karawajczyk Jacek Górski Artur Korzeniowski Zbigniew Ma?kiewicz Gotfryd Kupryszewski Renata Glo?nicka 《Cardiovascular pathology》2002,11(4):238-243
Acute coronary syndromes (ACS), including unstable angina (UA) and acute myocardial infarction (MI), are clinical manifestations of a progressive atherosclerotic process. Antibodies (Ab) to heat shock proteins (hsp) have been reported to be associated with atherosclerosis. Blood samples from 35 patients with ACS and 20 healthy volunteers were tested for Ab to human hsp60 by an enzyme-linked immunosorbent assay (ELISA). Levels of specific serum Ab against hsp60 were significantly elevated in patients with ACS when compared to clinically healthy subjects. To determine the antigenic determinants recognized by these Ab, antibody binding to seven peptides, selected from the hydrophilic and acrophilic regions of the human hsp60 molecule, was assessed. Despite the individual variation in the immune response among patients, one immunodominant region was revealed corresponding to the hsp60 (409-424) peptide. The identification of this epitope may be important for understanding the function of this protein in the atherosclerotic process. 相似文献
10.
The adhesion of human leukocytes to self-assembled monolayers of well-defined surface chemistry was investigated in vitro. Polymorphonuclear (PMN) and mononuclear leukocytes were isolated from human blood by centrifugation techniques. The effect on adhesion of cell activation produced by pre-incubation of leukocytes with phytohemagglutinin (PHA) and phorbol 12-myristate 13-acetate (PMA) was also studied. Gold substrates were modified by treatment with alkanethiols with three different terminal chemical groups: COOH, OH, and CH(3). After incubation with the two subpopulations of leukocytes, the monolayers were washed, treated with fixative, stained with a Giemsa method, and observed by light microscopy to quantify the number of attached leukocytes. Comparative quantification of the density of leukocyte adhesion to the three types of self-assembled monolayers was determined. The hydrophobic surface expressing CH(3) was found to be the one that induced the highest adhesion density of leukocytes, both of PMN and mononuclear cells. In vitro activation of both mononuclear and PMN leukocytes further increased cell adhesion to the chemically defined monolayers that were used. This enhancement was higher for PHA-activated than for PMA-stimulated mononuclear cells, whereas PMA treatment of neutrophils resulted in a higher rate of adhesion of these cells than PHA stimulation. 相似文献