全文获取类型
收费全文 | 9166篇 |
免费 | 578篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 237篇 |
妇产科学 | 262篇 |
基础医学 | 1443篇 |
口腔科学 | 223篇 |
临床医学 | 773篇 |
内科学 | 2137篇 |
皮肤病学 | 214篇 |
神经病学 | 984篇 |
特种医学 | 316篇 |
外科学 | 808篇 |
综合类 | 42篇 |
一般理论 | 5篇 |
预防医学 | 739篇 |
眼科学 | 191篇 |
药学 | 601篇 |
中国医学 | 53篇 |
肿瘤学 | 742篇 |
出版年
2024年 | 10篇 |
2023年 | 102篇 |
2022年 | 231篇 |
2021年 | 340篇 |
2020年 | 226篇 |
2019年 | 269篇 |
2018年 | 313篇 |
2017年 | 236篇 |
2016年 | 278篇 |
2015年 | 321篇 |
2014年 | 405篇 |
2013年 | 469篇 |
2012年 | 771篇 |
2011年 | 783篇 |
2010年 | 401篇 |
2009年 | 394篇 |
2008年 | 562篇 |
2007年 | 619篇 |
2006年 | 557篇 |
2005年 | 564篇 |
2004年 | 486篇 |
2003年 | 398篇 |
2002年 | 356篇 |
2001年 | 48篇 |
2000年 | 48篇 |
1999年 | 63篇 |
1998年 | 80篇 |
1997年 | 66篇 |
1996年 | 52篇 |
1995年 | 57篇 |
1994年 | 31篇 |
1993年 | 49篇 |
1992年 | 20篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 15篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1976年 | 5篇 |
1974年 | 6篇 |
1969年 | 4篇 |
1946年 | 3篇 |
排序方式: 共有9819条查询结果,搜索用时 15 毫秒
41.
Giuseppe A. Ramirez Valentina Canti Stefania Del Rosso Roberta Erra Lucia Moiola Marco Magnoni 《Autoimmunity》2020,53(1):21-27
AbstractBackground: Systemic lupus erythematosus (SLE) is associated with a constellation of complications affecting multiple organs, including neuropsychiatric manifestations (NPSLE) and ischaemic events, leading to increased long-term morbidity. Antiphospholipid antibodies (aPL) are a major determinant of vascular inflammation and thromboembolic risk. The diagnostic role of anti-phosphatidylserine/prothrombin (aPS/PT) antibodies in this setting is incompletely defined.Aim: To verify whether aPS/PT add to diagnostics and disease stratification in patients with SLE with or without other aPL.Methods: 131 consecutive patients were studied, including 20 patients with SLE and secondary antiphospholipid syndrome (APS). aPS/PT IgG and IgM were assessed through ELISA and patients were stratified based on the presence of other aPL, on their clinical and laboratory features at time of blood sampling and on their clinical history. Synthetic indices of disease activity, chronic damage and cardiovascular risk were calculated at time of venipuncture.Results: Fifty-one (38.9%) patients with SLE had aPS/PT and 15 (11.5%) patients had aPS/PT as the only aPL (aPS/PT-only). aPS/PT-only patients had a significantly higher prevalence of NPSLE than quadruple aPL-negative patients (p?=?.007). Patients with aPS/PT were more likely to have a history of ischaemia, thrombocytopenia and Libman–Sacks’ endocarditis. The presence of aPS/PT also associated with previous accrual of at least one damage item (p?=?.043), but had limited predictive values for damage progression in the short term.Conclusion: aPS/PT antibodies provide non-redundant information that could contribute to risk assessment and stratification of patients with SLE. 相似文献
42.
Lucia MB Rutella S Leone G Larocca LM Vella S Cauda R 《Journal of acquired immune deficiency syndromes (1999)》2002,30(4):369-378
P-glycoprotein (P-gp) transports a wide range of structurally unrelated drugs, such as HIV protease inhibitors (PIs) and cytotoxic compounds such as anthracyclines. Because modification of P-gp phenotype and function is an important underlying mechanism of drug interactions, the current study was conducted in order to evaluate whether highly active antiretroviral therapy (HAART), HIV plasma viral load (VL), or cancer chemotherapy may induce in vivo changes of P-gp phenotype in peripheral blood mononuclear cells (PBMCs) from HIV-infected treatment-naive and -experienced subjects at different stages of HIV infection and/or disease, including patients with HIV-associated Kaposi sarcoma (KS). Our results show that neither HAART nor HIV VL, nor the stage of HIV infection and/or disease, significantly alter P-gp expression on PBMCs. In particular, surface P-gp expression is expressed at low levels by T-cell subsets, B cells, and NK cells, whereas almost all monocytes are double positive and these results are not modified by HIV PI-containing regimens. By contrast, a significant phenotype modification is detected in PBMCs from AIDS/KS patients after challenge with the liposomal formulation of the anthracycline doxorubicin (L-DOX) with the higher expression reached 24 hours after the end of the drug infusion. In addition, accumulation of L-DOX is unaffected by P-gp-mediated drug efflux as documented by in vitro experiments, in sharp contrast to the kinetic of free DOX, based on HIV PI blockade experiments. Finally, P-gp expression was found in KS spindle cells from HIV-infected treatment-naive AIDS/KS patients. We conclude that P-gp phenotype in PBMCs and specific subsets is not altered by HAART and/or HIV, whereas a significant increase is induced by specific anticancer drugs such as L-DOX. Moreover, HIV PIs possess an inhibitory effect on P-gp function that may improve DOX sensitivity in KS spindle cells. 相似文献
43.
Werahera PN Miller GJ Torkko K Crawford ED Stewart JS Deantoni EP Miller HL Lucia MS 《Human pathology》2004,35(7):798-807
Advances in the detection of carcinoma of the prostate during the last 15 years have accounted for a sharp increase and then an abrupt decrease in the incidence of the disease. A more recent decline in its mortality rates has been variously interpreted as either the success of early detection and improved treatment or lead-time bias. The recently reported Prostate Cancer Prevention Trial had an overall detection rate that approached the 30%-40% prevalence rates reported in autopsy series in which men died of other causes. However, the prognostic information that can be obtained from prostate cancer found on biopsy is limited. Three-dimensional computer modeling is one technique that allows multiple studies on "immortal" prostates to test methods of biopsy sampling accuracy and to assist in the determination of the disease's severity. Computer modeling can assess detection rates and assesses tumor multifocality and heterogeneity. It can provide a more accurate representation of tumor volume, aiding in therapeutic decision making, and can assess sampling errors of various biopsy methods. It has been shown to be superior to wire-frame technique by immortalizing the original shape and dimensions of the surgically excised prostate gland. Moreover, our 3-dimensional computer modeling system improves upon other systems: It is more than a simple extension of the planimetric technique, and it is able to demarcate clearly the boundaries of Gleason grades just 1 grade apart. 相似文献
44.
A STAT4-dependent Th1 response is required for resistance to the helminth parasite Taenia crassiceps 总被引:2,自引:0,他引:2 下载免费PDF全文
Rodríguez-Sosa M Saavedra R Tenorio EP Rosas LE Satoskar AR Terrazas LI 《Infection and immunity》2004,72(8):4552-4560
To determine the role of STAT4-dependent Th1 responses in the regulation of immunity to the helminth parasite Taenia crassiceps, we monitored infections with this parasite in resistant mice lacking the STAT4 gene. While T. crassiceps-infected STAT4(+/+) mice rapidly resolved the infection, STAT4(-/-) mice were highly susceptible to infection and displayed large parasite loads. Moreover, the inability of STAT4(-/-) mice to control the infection was associated with the induction of an antigen-specific Th2-type response characterized by significantly higher levels of Th2-associated immunoglobulin G1 (IgG1) and total IgE as well as interleukin-4 (IL-4), IL-10, and IL-13 than those in STAT4(+/+) mice, who produced significantly more gamma interferon. Furthermore, early after infection, macrophages from STAT4(-/-) mice produced lower levels of the pro-inflammatory cytokines IL-12, tumor necrosis factor alpha, IL-1 beta, and nitric oxide (NO) than those from STAT4(+/+) mice, suggesting a pivotal role for macrophages in mediating protection against cysticercosis. These findings demonstrate a critical role for the STAT4 signaling pathway in the development of a Th1-type immune response that is essential for mediating protection against the larval stage of T. crassiceps infection. 相似文献
45.
Down-regulation of nitric oxide synthase-2 and cyclooxygenase-2 pathways by p53 in squamous cell carcinoma 总被引:7,自引:0,他引:7 下载免费PDF全文
Gallo O Schiavone N Papucci L Sardi I Magnelli L Franchi A Masini E Capaccioli S 《The American journal of pathology》2003,163(2):723-732
The goal of this study was to analyze the correlation between inducible nitric oxide synthase (iNOS) and COX-2 activities and p53 gene status in head and neck squamous cell carcinomas (HNSCCs) in vivo and in vitro. In a series of 43 HNSCCs we observed an up-regulation of both iNOS and COX-2 pathways in tumor tissues and both activities were correlated each other (rs = 0.612 and P = 0.0002). We also found that p53-mutated HNSCCs (25 cases, 58.1%) showed higher levels of iNOS activity and cGMP in comparison with wild-type p53 tumors (18 cases, 41.9%) (P = 0.0005 and P = 0.01), as well as higher iNOS immunohistochemical expression (P = 0.03). Analogously, higher PgE2 levels were documented in p53-mutated HNSCCs when compared with wild-type p53 tumors (P = 0.015) and COX-2 protein expression was higher in p53-mutated HNSCCs (P = 0.007). A431 cancer cells expressing a p53 temperature-sensitive mutant showed an approximately 1.9- and 2.6-fold decrease in spontaneous NO(2-)/NO(3-) and PgE2 synthesis at permissive temperature, respectively, when compared with the same cells at nonpermissive temperature (P 相似文献
46.
47.
Martini L Fini M Giavaresi G Torricelli P de Pretto M Rimondini L Giardino R 《Artificial cells, blood substitutes, and immobilization biotechnology》2003,31(4):449-466
Over the past decade extracorporeal shock-wave therapy (ESWT) has been increasingly applied to orthopaedic and musculoskeletal pathologies, the aim of this study was to assess how the energy density of the shock waves and the number of impulses affect viability, differentiation and synthetic activity of osteoblasts. Primary sheep osteoblasts cultures were treated with ESWT with an electro-hydraulic shock wave generator by selecting three different energy levels (14-21-28 kV corresponding at 0.15-0.31-0.40 mJ/mm2) and two different total numbers of impulses (500, 1000) for each level. At the end of treatment, cell counts and viability were recorded. Cells were then cultivated for 48 hours starting from a concentration of 1 x 10(4) cells/ml. The biological activity and viability were evaluated at 24 and 48 hours after treatment. No cytodestructive effects were observed in Group A, while a cytodestructive effect of ESWT was seen in cultures receiving the highest energy treatments. The different shock wave treatment induced differences in MTT assays after 24 and 48 hours, in particular the highest level showed a detrimental effect on cell respiration at both experimental times as compared to the Control Group and the protein metabolism was generally depressed by ESWT with impulses at the highest energy level. After 24 hours such effect further increased with the growing number of impulses. The lowest energy level appeared to significantly improve the metabolic parameter in primary cell cultures as compared to controls when 500 impulses were selected. The current study has demonstrated that one of the most important aspects to be considered is not the total number of impulses used but the energy level of the shock waves, thus confirming that ESWT has a dose-dependent effect on cells. 相似文献
48.
49.
Buckner C Gines LG Saunders CJ Vojtech L Srivastava I Gettie A Bohm R Blanchard J Barnett SW Safrit JT Stamatatos L 《Virology》2004,320(1):167-180
The potential of vaccine-elicited anti-HIV envelope antibodies to control HIV-infection was evaluated by immunizing macaques with the HIV envelope protein and transiently depleting them of their CD8+ cells before intravenous challenge with the pathogenic CCR5-tropic SIV/HIV chimeric virus, SHIV(SF162P4). Although sterilizing immunity was not achieved, all vaccinated animals effectively controlled infection and remained free of disease for the duration of observation (over 3 years). In contrast, during the same period, the control animals progressed to disease. Both the vaccinees and the controls developed robust cell-mediated antiviral and neutralizing antibody responses following infection. A comparative analysis of these responses suggests that the more effective long-term control of infection by the vaccinated animals is due to the more rapid development of anti-HIV envelope antibodies. These studies suggest that priming by vaccination of B cell anti-HIV envelope responses maybe crucial for the long-term control of HIV infection. 相似文献
50.
Can energy drinks reduce the depressor effect of ethanol? An experimental study in mice 总被引:3,自引:0,他引:3
Ferreira SE Hartmann Quadros IM Trindade AA Takahashi S Koyama RG Souza-Formigoni ML 《Physiology & behavior》2004,82(5):841-847
Although the popularization of the combined use of alcoholic beverages and energy drinks (ED) containing caffeine, taurine and other substances has increased, there are no controlled experimental studies on the effects of ED alone or combined with ethanol. This work aimed at evaluating the effects of different doses of ED combined or not with ethanol, on the locomotor activity of Swiss mice. The administration of 3.57, 10.71 or 17.86 ml/kg of ED alone increased the locomotor activity of the animals in relation to a control group. Low doses of ethanol (0.5, 1.0 and 1.5 g/kg) alone or in combination with 10.71 ml/kg of ED did not affect their locomotor activity. However, the reduction of activity observed after 2.5 g/kg of ethanol was antagonized by 10.71 ml/kg of ED. Further studies on the mechanisms of this interaction are still needed. 相似文献