全文获取类型
收费全文 | 1114篇 |
免费 | 54篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 68篇 |
妇产科学 | 8篇 |
基础医学 | 122篇 |
口腔科学 | 21篇 |
临床医学 | 143篇 |
内科学 | 262篇 |
皮肤病学 | 51篇 |
神经病学 | 22篇 |
特种医学 | 298篇 |
外科学 | 44篇 |
综合类 | 23篇 |
预防医学 | 39篇 |
眼科学 | 5篇 |
药学 | 60篇 |
中国医学 | 2篇 |
肿瘤学 | 55篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 39篇 |
2012年 | 23篇 |
2011年 | 12篇 |
2010年 | 34篇 |
2009年 | 55篇 |
2008年 | 21篇 |
2007年 | 53篇 |
2006年 | 20篇 |
2005年 | 20篇 |
2004年 | 11篇 |
2003年 | 11篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 71篇 |
1997年 | 80篇 |
1996年 | 101篇 |
1995年 | 61篇 |
1994年 | 58篇 |
1993年 | 52篇 |
1992年 | 16篇 |
1991年 | 15篇 |
1990年 | 20篇 |
1989年 | 37篇 |
1988年 | 36篇 |
1987年 | 34篇 |
1986年 | 44篇 |
1985年 | 40篇 |
1984年 | 8篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 13篇 |
1973年 | 2篇 |
排序方式: 共有1224条查询结果,搜索用时 29 毫秒
81.
JC Jiménez-Mendoza FE Rivera-López MF González-Lara RD Valdez-Echeverría GE Castro-Narro A Tore LF Uscanga-Domínguez C Moctezuma-Velázquez 《Annals of hepatology》2022,27(3):100684
Introduction and ObjectivesThe emergence of SARS-CoV-2, which causes the coronavirus disease (COVID-19) has caused a great impact on healthcare systems worldwide, including hepatitis B and C viruses screening and elimination programs. The high number of COVID-19 hospitalizations represent a great opportunity to screen patients for hepatitis B virus (HBV) and hepatitis C virus (HCV), which was the aim of this study.Material and MethodsCross-sectional, retrospective study performed between April 2020 and 20201 at a referral center in Mexico dedicated to the care of adults with severe/critical COVID-19. We retrieved clinical, demographic, and laboratory results from each patient´s medical records, including antibodies against HCV (anti-HCV), HBV surface antigen (HBsAg), antibodies against the HBV core antigen (anti-HBcAg), and antibodies against HBsAg (anti-HBsAg).ResultsOut of 3620 patients that were admitted to the hospital, 24 (0.66%), 4 (0.11%), and 72 (1.99%) tested positive for anti-HCV, HBsAg, and anti-HBcAg, respectively. Of all seronegative patients, 954 (27%) had undetectable anti-HBsAg and 401 (12%) had anti-HBsAg at protective levels. Blood transfusion was the most relevant risk factor. Only 9.7% of the anti-HBc positive, 25% of the HBsAg positive, and 52% of the anti-HCV positive were aware of their serological status.ConclusionsIn this study we found a prevalence of anti-HCV of 0.66%, HBsAg in 0.11%, and isolated anti-HBcAg in 1.99%. We also found that HBV vaccination coverage has been suboptimal and needs to be reinforced. This study gave us a trustworthy insight of the actual seroprevalence in Mexico, which can help provide feedback to the Hepatitis National Elimination Plan. 相似文献
82.
83.
84.
85.
Ramya Chandrasekaran Thiagarajan Madheswaran Nagendran Tharmalingam Rajendran JC Bose Hansoo Park Don-Hyung Ha 《Drug discovery today》2021,26(1):94-105
Gold nanoparticles (AuNPs) have garnered much attention as contrast agents for computerized tomography (CT) because of their facile synthesis and surface functionalization, in addition to their significant X-ray attenuation and minimal cytotoxicity. Cell labeling using AuNPs and tracking of the labeled cells using CT has become a time-efficient and cost-effective method. Actively targeted AuNPs can enhance CT contrast and sensitivity, and further reduce the radiation dosage needed during CT imaging. In this review, we summarize the state-of-the-art use of AuNPs in CT for cell tracking, including the precautionary steps necessary for their use and the difficulty in translating the process into clinical use. 相似文献
86.
Morales-Medina JC Mejorada A Romero-Curiel A Aguilar-Alonso P León-Chávez BA Gamboa C Quirion R Flores G 《Neuropharmacology》2008,55(8):1313-1320
Nitric oxide (NO) is associated with dopamine (DA) release. Previously, we demonstrated that rats treated with a non-selective nitric oxide synthase inhibitor, N-omega-nitro-l-arginine (l-NNA) at postnatal days 4-6 (PD4-6) show increased locomotion and disrupt neuronal cytoarchitecture after puberty (PD60). Here, we investigate whether the modulation of NO production in rats at PD4-6 causes long term changes of NO system, its impact on DA innervation, and schizophrenia-like behaviors. NO levels were measured in seven brain areas at PD35, PD60, PD90, and PD120. Autoradiographic studies explored the effect of l-NNA on the expression of D1 and D2 receptors in the caudate-putamen (CPu) and nucleus accumbens (NAcc) at PD60. Locomotor activity was assessed at PD60 using the non-selective DA agonists, amphetamine and apomorphine, and the selective DA receptor agonist [D2, quinpirole; D3, 7-hydroxy-N,N-di-n-propylaminotetralin ((±)-7-OH-DPAT)]. l-NNA treatment produced decreases in NO levels in the frontal cortex, striatum, brainstem and cerebellum, while in the occipital cortex changes were observed at PD120. Hippocampus and temporoparietal cortex showed differential levels of NO. Receptor autoradiography revealed increases in D1 receptor levels in the NAcc (shell), while decreases in D2 receptor binding were observed in the CPu and NAcc (core). Amphetamine and quinpirole treatments resulted in increases in locomotion. In contrast, treatment with 7-OH-DPAT produced hypolocomotion at low doses, while increased locomotion was seen at the highest dose. These results show that modulation of NO levels early postnatally (PD4-6) produces long term alteration in NO levels, with possible consequences on DA transmission, and related behaviors relevant to schizophrenia. 相似文献
87.
Tina Dorn Manon Ceelen Ming-Jan Tang Joyce L Browne Koos JC de Keijzer Marcel CA Buster Kees Das 《BMC public health》2011,11(1):190
Background
As in many European countries, access to care is decreased for undocumented migrants in the Netherlands due to legislation. Studies on the health of undocumented migrants in Europe are scarce and focus on care-seeking migrants. Not much is known on those who do not seek care. 相似文献88.
Differences in magnetic resonance (MR) imaging signal-to-noise (S/N) performance between saddle-shaped and solenoidal coils have been postulated. Each coil shape is tied to a particular magnetic field configuration, so that they are not typically interchangeable except in special situations. The solenoidal coil is predicted to have a two- to three-fold advantage over the saddle-shaped coil. Simple basic arguments raise a dispute with this assertion. Experiments show that both coils produce essentially equivalent S/N levels. 相似文献
89.
Forty-five patients undergoing double-contrast barium enema examinations were studied to identify the incidence of transient bacteremia associated with the examination. Blood cultures were obtained immediately prior to the examination and at 5, 10, and 20 minutes after the start of the examination. Blood samples were cultured in both aerobic and anaerobic media, and four of these cultures were positive for organisms that are common skin contaminants. No bacteremia was identified from enteric pathogens. The data herein suggest that patients with cardiac valvular disease are not at greater risk of bacteremia during double-contrast barium enema examinations. 相似文献
90.
Pheochromocytoma and the normal adrenal medulla: improved visualization with I-123 MIBG scintigraphy 总被引:1,自引:0,他引:1
Lynn MD; Shapiro B; Sisson JC; Beierwaltes WH; Meyers LJ; Ackerman R; Mangner TJ 《Radiology》1985,155(3):789-792
The radiopharmaceutical iodine 131 metaiodobenzylguanidine (I-131 MIBG) has been shown to locate pheochromocytomas scintigraphically with a false-negative rate of approximately 13%. To improve image quality and reduce the false-negative rate, I-123 was examined as a radioactive label for MIBG, as it has many advantages over I-131, including superior dosimetry and better detection efficiency. Diagnostic doses of 0.5 mCi (18.5 MBq) I-131 MIBG and 10.0 mCi (370.0 MBq) I-123 MIBG with nearly equivalent radiation dosimetries were compared in 18 patients with known or suspected pheochromocytomas. Images of superior quality were obtained with I-123 MIBG in 18 of 18 patients, and in eight cases lesions not visualized on I-131 MIBG scintigraphy were portrayed. A further advantage of I-123 MIBG is that it permits single photon emission computed tomography (SPECT). This was performed in six cases and provided additional information in three cases. The adrenal medullae were definitely visualized using I-123 scintigraphy in eight of 14 patients still possessing adrenal glands, whereas I-131 MIBG images portrayed the adrenal medulla in only one of 14 cases. Five remaining patients had multiple abdominal tumor deposits that were difficult to differentiate from normal adrenal medullae. 相似文献