全文获取类型
收费全文 | 5789篇 |
免费 | 324篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 337篇 |
妇产科学 | 74篇 |
基础医学 | 623篇 |
口腔科学 | 119篇 |
临床医学 | 576篇 |
内科学 | 1279篇 |
皮肤病学 | 85篇 |
神经病学 | 494篇 |
特种医学 | 176篇 |
外科学 | 1017篇 |
综合类 | 174篇 |
一般理论 | 3篇 |
预防医学 | 287篇 |
眼科学 | 149篇 |
药学 | 316篇 |
中国医学 | 15篇 |
肿瘤学 | 380篇 |
出版年
2023年 | 59篇 |
2022年 | 75篇 |
2021年 | 180篇 |
2020年 | 121篇 |
2019年 | 159篇 |
2018年 | 192篇 |
2017年 | 130篇 |
2016年 | 156篇 |
2015年 | 149篇 |
2014年 | 236篇 |
2013年 | 245篇 |
2012年 | 402篇 |
2011年 | 443篇 |
2010年 | 238篇 |
2009年 | 226篇 |
2008年 | 330篇 |
2007年 | 320篇 |
2006年 | 303篇 |
2005年 | 257篇 |
2004年 | 251篇 |
2003年 | 254篇 |
2002年 | 218篇 |
2001年 | 120篇 |
2000年 | 108篇 |
1999年 | 100篇 |
1998年 | 68篇 |
1997年 | 55篇 |
1996年 | 47篇 |
1995年 | 28篇 |
1994年 | 46篇 |
1993年 | 32篇 |
1992年 | 46篇 |
1991年 | 43篇 |
1990年 | 34篇 |
1989年 | 40篇 |
1988年 | 49篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 40篇 |
1984年 | 32篇 |
1983年 | 25篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 18篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 13篇 |
1974年 | 16篇 |
1971年 | 15篇 |
排序方式: 共有6152条查询结果,搜索用时 0 毫秒
21.
Changes in Lower Leg Anterior Compartment Pressure Before,During, and After Creatine Supplementation
Potteiger JA Carper MJ Randall JC Magee LJ Jacobsen DJ Hulver MW 《Journal of Athletic Training》2002,37(2):157-163
OBJECTIVE: To determine if 35 days of creatine supplementation (Cr) followed by 28 days of no supplementation altered lower leg anterior compartment pressure (ACP) at rest and after exercise. DESIGN AND SETTING: Subjects were divided into 2 treatment groups: (1) high dose (0.3 g Cr.kg body mass(-1).d(-1) for 7 days followed by 0.03 g Cr.kg body mass(-1).d(-1) for 28 days), or (2) low dose (0.03 g Cr.kg body mass(-1).d(-1) for 35 days). After 35 days, supplementation was terminated, and no Cr was ingested for 28 days. SUBJECTS: Sixteen physically active, healthy, college-aged males (O(2)max = 47.6 +/- 5.1 mL.kg(-1).min(-1)). MEASUREMENTS: At baseline, 7 days and 35 days of supplementation, and 28 days postsupplementation, ACP was measured preexercise and immediately, 1, 5, 10, and 15 minutes postexercise after a treadmill run at 80% O(2)max. RESULTS: For ACP, there was no significant group-by-time interaction, but there was a significant time effect for group when the data were combined. ACP was significantly increased at preexercise, immediately postexercise, and 1, 5, and 10 minutes from baseline to 7 days. ACP remained significantly elevated from baseline at 35 days immediately postexercise and 1 minute postexercise. After 28 days of no supplementation, ACP began to return to presupplementation levels, with only the 1-minute postexercise measurement significantly elevated from baseline. CONCLUSIONS: Creatine supplementation increased ACP at rest and after exercise, and ACP began to return to normal after 28 days of no supplementation. 相似文献
22.
23.
Anti-L3T4 antibody treatment suppresses hepatic granuloma formation and abrogates antigen-induced interleukin-2 production in Schistosoma mansoni infection 总被引:5,自引:12,他引:5 下载免费PDF全文
In murine schistosomiasis mansoni, granulomatous inflammation is an immune response that involves egg antigen presentation to T cells in the context of class II major histocompatibility complex determinants and subsequent inflammatory lymphokine production by delayed-hypersensitivity (TDH) lymphocytes. In the present study, monoclonal antibodies directed against L3T4, I-A, and Lyt-2 molecules were injected intraperitoneally into S. mansoni-infected mice to study the role of these membrane antigens in the process of granuloma formation. A dramatic suppression of the hepatic granuloma size and antigen-induced interleukin-2 (IL-2) production by spleen cells was seen in mice that received anti-L3T4 monoclonal antibody treatment. The total number of cells, especially the L3T4+ T cells, was greatly diminished in the spleens. Furthermore, histopathological study of the granulomas in stained liver sections demonstrated the paucity of eosinophils and macrophages, absence of epithelioid cells and multinucleated giant cells, and minimal collagen deposition within the lesions. Damaged hepatocytes were also seen surrounding these ill-formed granulomas. In contrast, anti-I-A monoclonal antibody treatment partially suppressed IL-2 production, although granuloma size and cellular composition remained the same. Mice that received anti-Lyt-2 monoclonal antibody did not show any changes in either IL-2 production or hepatic granulomatous inflammation. The data presented in this paper indicate a crucial role for L3T4 molecules present on a subset of class II major histocompatibility complex-restricted TDH cells in IL-2 production and the generation of the granulomatous response. 相似文献
24.
Pathologic anxiety, marked by inappropriate apprehension and/or fear, causes patients to seek help. Anxiety is associated with a wide variety of physical illnesses, and these must be initially considered when making a diagnosis. Similarly, anxiety associated with a wide variety of psychiatric syndromes must also be considered. Finally, the possibility of transient situational anxiety is ever present. Once it is determined that a primary anxiety disorder exists, then the presence or absence of phobias, panic attacks, and chronic "free-floating" anxiety will fully characterize the disorder. With an accurate diagnosis in hand, a multifaceted treatment approach can be designed. Effective treatments now exist for phobic and panic disorders, and more effective treatment for chronic generalized anxiety may be forthcoming. 相似文献
25.
Catherine A. Hogan ChunHong Huang Malaya K. Sahoo Hannah Wang Becky Jiang Mamdouh Sibai Marisa Holubar Roshni Mathew James Zehnder Benjamin A. Pinsky 《Emerging infectious diseases》2021,27(2):632
We developed an assay that detects minus-strand RNA as a surrogate for actively replicating severe acute respiratory syndrome coronavirus 2. We detected minus-strand RNA in 41 persons with coronavirus disease up to 30 days after symptom onset. This assay might inform clinical decision-making about patient infectiousness. 相似文献
26.
Maria Ruden Christopher H. Olivares Mathew Q. Fakhoury Alicia Roston Patricia P. Vidal Courtney M.P. Hollowell Sarah P. Psutka 《Urologic oncology》2021,39(1):73.e19-73.e25
PurposeTo compare the clinical presentation, treatment receipt, and oncologic outcomes between human immunodeficiency virus-seropositive (HIV+) and seronegative (HIV?) men with prostate cancer (CaP) matched by age, clinical stage, and race.Materials and methodsA retrospective review of 3,135 men treated for CaP from 2000 to 2016 was performed. HIV+ patients (N = 46) were matched 1:2 to 3 to HIV? men (N = 137) by age, race, and clinical stage. Clinicopathologic features and primary treatment received were compared between cohorts. Associations between HIV status and progression-free, cancer-specific, and overall survival were compared by HIV status using the Kaplan-Meier method and Cox proportional hazards analysis.ResultsAfter matching, men with and without HIV were similar with respect initial prostate-specific antigen, Gleason Sum, and Eastern Cooperative Oncology Group (ECOG) performance status. Among HIV+ men, 67.4% had a history of acquired immune deficiency syndrome, and 91.3% were on highly active antiretroviral therapy at CaP diagnosis. Among men with localized disease, HIV+ men were more likely to receive radiation (59.5% vs. 44.8%) or no therapy (13.5% vs. 4.3%) and less likely to receive surgery (16.2% vs. 30.2%), or to initiate active surveillance (10.8% vs. 16.4%; P = 0.04 overall). There were no differences in rates of clinical progression, development of castration resistance, or CaP death by HIV status. However, HIV+ status was associated with inferior overall survival (hazard ratio 2.89, P = 0.04).ConclusionsWhile most HIV+ patients had a history of acquired immune deficiency syndrome; HIV was well controlled in the majority of patients at the time of CaP diagnosis. While oncologic outcomes were similar between HIV+ and HIV? men, significant differences in treatment selection were observed. Further research is necessary to understand differences in treatment election by HIV status and to define optimal CaP treatment selection in men with HIV. 相似文献
27.
Charlotte V. Hobbs Jan Drobeniuc Theresa Kittle John Williams Paul Byers Panayampalli S. Satheshkumar Kengo Inagaki Meagan Stephenson Sara S. Kim Manish M. Patel Brendan Flannery CDC COVID- Response Team CDC COVID- Response Team Bailey Alston Shanna J. Bolcen Darbi Boulay Peter Browning Li Cronin Ebenezer David Tonya Hayden Han Li Travis Lim Panagiotis Maniatis Palak Patel Mathew Pauly Amanda Poe Lili Punkova Vera Semenova Evelene P. Steward-Clark Alexandra Tejada Briana Zellner 《MMWR. Morbidity and mortality weekly report》2021,70(9):312
28.
Post-infantile giant cell hepatitis: histological and immunohistochemical study. 总被引:2,自引:1,他引:2 下载免费PDF全文
S J Johnson J Mathew R N MacSween M K Bennett A D Burt 《Journal of clinical pathology》1994,47(11):1022-1027
AIM--To determine the composition of the inflammatory infiltrate and to check for the presence of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in nine cases of post-infantile giant cell hepatitis. METHODS--The clinical, serological, and histological features of the nine cases were reviewed. Immunohistochemistry was used on liver biopsy specimens from six cases to: (i) characterise the lymphocytic infiltrate; (ii) assess the monocyte/macrophage response; (iii) detect "activated" perisinusoidal cells; and (iv) detect CMV and EBV antigens. Electron microscopic examination was carried out in two cases. RESULTS--Four patients had serological features suggestive of autoimmune chronic active hepatitis; in the other five cases the aetiology was obscure. Two patients presented with neurological symptoms. Hepatitis resolved completely in one patient; two patients showed clinical improvement; and one remained stable. Cirrhosis developed in three patients, one of whom proceeded to liver transplantation, and three patients died. Portal inflammation was present in all cases and lymphocytic piecemeal necrosis in eight cases, but intra-acinar inflammation associated with hepatocyte necrosis was observed in only five cases. The inflammatory infiltrate was composed predominantly of T lymphocytes; an increase in monocyte/macrophage cells was also observed. Mallory bodies, often with associated neutrophilic infiltrate, were present in four cases, and bilirubinostasis was a feature in four cases. "Activated" perisinusoidal cells were present, especially in relation to areas of inflammation, necrosis, and fibrosis. There was severe fibrosis or cirrhosis in five cases. Paramyxoviral nucleocapsids were not seen in the two cases examined ultrastructurally. CONCLUSIONS--Post-infantile giant cell hepatitis should be viewed as a heterogeneous clinical and aetiological entity encompassing cases of hepatitis with extensive giant cell hepatocyte transformation. 相似文献
29.
The purpose of this study was to determine the importance of inhibition of beta-adrenergic function in thiopentone-induced
myocardial depression. Using an isolated, electrically stimulated rat left atria model, contractile dose-response curves to
thiopentone (200 μM, 400 μM, 600 μM, 800 μM) were shifted to the right in preparations treated with 10− 3 M dibutyryl cyclic adenosine monophosphate (cAMP) compared with atria stimulated with 10− 6 M isoprenaline, demonstrating that inhibition of beta-adrenergic mechanisms by thiopentone is physiologically important.
Depression by thiopentone was similar in atria treated with 10− 5 M forskolin compared with preparations stimulated with 10− 6 M isoprenaline, indicating that thiopentone does not block beta-adrenergic receptors. It is concluded that thiopentone depresses
myocardial function by several mechanisms, one of which involves inhibition of the adenyl cyclase cascade. The adenyl cyclase
enzyme is a likely site where thiopentone inhibits the system; however, other components of the cascade may also be involved.
L’objectif de cette étude consiste à déterminer l’influence de l’inhibition de l’activité β-adrenergique sur la dépression
myocardique induite par le thiopentone. A l’aide d’un modèle constitué d’une oreillette gauche de rat stimulée électriquement,
la relation dose-effet du thiopentone sur la contractilité (200 μM, 400 μM, 600 μM, 800 μM) se déplace vers la droite dans
des préparations traitées avec de l’adénosine monophosphorique cyclique (cAMP) 10− 3 M comparativement à des oreillettes stimulées avec de l’isoprénaline 10− 6 M, ce qui démontre que l’inhibition β-adrénergique provoquée par le thiopentone est physiologiquement importante. La dépression
de l’oreillette provoquée par le thiopentone est identique à celle que produit la forskoline 10− 5 M comparativement à celle de l’isoprénaline 10− 6 M, ce qui indique que le thiopentone n’inhibe pas les récepteurs β-adrénergiques. Les auteurs concluent que le thiopentone
déprime la fonction myocardique par plusieurs mécanismes qui impliquent l’inhibition de la cascade de l’adényl cyclase. L’inhibition
du système se produit vraisemblablement au niveau de l’enzyme adényl cyclase; cependant, il est possible que d’autres éléments
de la cascade de l’adényl cyclase soient impliqués. 相似文献
30.