全文获取类型
收费全文 | 2385篇 |
免费 | 126篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 50篇 |
妇产科学 | 34篇 |
基础医学 | 298篇 |
口腔科学 | 270篇 |
临床医学 | 181篇 |
内科学 | 419篇 |
皮肤病学 | 43篇 |
神经病学 | 126篇 |
特种医学 | 173篇 |
外国民族医学 | 1篇 |
外科学 | 184篇 |
综合类 | 135篇 |
预防医学 | 243篇 |
眼科学 | 42篇 |
药学 | 210篇 |
1篇 | |
中国医学 | 13篇 |
肿瘤学 | 78篇 |
出版年
2023年 | 18篇 |
2022年 | 33篇 |
2021年 | 68篇 |
2020年 | 50篇 |
2019年 | 69篇 |
2018年 | 99篇 |
2017年 | 59篇 |
2016年 | 68篇 |
2015年 | 81篇 |
2014年 | 103篇 |
2013年 | 120篇 |
2012年 | 166篇 |
2011年 | 149篇 |
2010年 | 97篇 |
2009年 | 81篇 |
2008年 | 108篇 |
2007年 | 122篇 |
2006年 | 87篇 |
2005年 | 66篇 |
2004年 | 63篇 |
2003年 | 43篇 |
2002年 | 55篇 |
2001年 | 37篇 |
2000年 | 45篇 |
1999年 | 45篇 |
1998年 | 54篇 |
1997年 | 45篇 |
1996年 | 47篇 |
1995年 | 29篇 |
1994年 | 32篇 |
1993年 | 27篇 |
1992年 | 25篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 32篇 |
1988年 | 29篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 29篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 23篇 |
1981年 | 12篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1974年 | 6篇 |
排序方式: 共有2545条查询结果,搜索用时 31 毫秒
21.
22.
Milena de Paiva Cavalcanti Filipe Dantas-Torres Suênia da Cunha Gonçalves de Albuquerque Rayana Carla Silva de Morais Maria Edileuza Felinto de Brito Domenico Otranto Sinval Pinto Brandão-Filho 《Molecular and cellular probes》2013,27(3-4):122-128
American cutaneous leishmaniasis (ACL) caused by Leishmania (Viannia) braziliensis is a neglected disease of humans in the New World that may also cause irreversible skin and eventually mucocutaneous lesions. This parasite can also infect dogs and represents a diagnostic challenge for veterinarians. Methods currently available for the diagnosis of ACL have a low sensitivity and may be time-consuming, representing a limit for treatment expedition of ACL. Quantitative real time PCR assays (qPCR) for the detection of L. (V.) braziliensis in canine blood samples were developed herein, and the detection limit and specificity of different molecular targets (kDNA and rDNA) evaluated. Of the protocols assessed, two qPCR assays, one targeting the kDNA and other the SSU rDNA of L. (V.) braziliensis, performed better, with detection limits of 100 fg and 10 pg, respectively. These assays were also used to test skin samples from humans with suspected ACL. The results indicate that the qPCR protocols developed represent an advance for the diagnosis of ACL in dogs and humans from this region, and provide a rapid and non-invasive diagnosis of the infection by L. (V.) braziliensis. Considering the quantitative nature of the assays, they will also be useful for monitoring treatment efficacy and preventing relapses in human patients in Brazil, although further studies are needed to critically evaluate the specificity of the qPCRs for their capacity to distinguish different Leishmania species and subspecies (represented by zymodemes) in other countries. Finally, molecular assays established may represent new tools for future basic and applied research focused on species identification, host–parasite associations, and infection dynamics in host and vector populations. 相似文献
23.
24.
老年大鼠松质骨骨重建的组织形态计量学研究 总被引:1,自引:0,他引:1
目的:研究老年大鼠及在促骨合成药前列腺素E2(PGE2)作用下松质骨骨重建和骨建造的形态计量学改变,探讨动物骨重建形态学新参数测量方法及其意义。方法:50只20月龄雄性Wistar大鼠随机分成5组,年龄对照组(基础组、10d和30d年龄对照组),PGE2给药组(分别10d和30d给予3mg/kg/d处理组)。用体内双荧光标记,不脱钙组织切片,粘合线(cement line)染色,骨组织形态计量学方法,测定骨重建和骨建造参数。结果:20月龄雄性大鼠胫骨近端松质骨的形成表面大多数为骨重建单位(占63.3%),少部分为骨建造单位(占26.7%);PGE2用药后骨重建单位增加1.5倍,骨建造单位增加4倍,比值倒置,成骨细胞10d时明显增多。说明PGE2通过刺激成骨细胞骨合成而介民导骨建造性骨增加和骨重建性骨量增加,并以前为主。结论:老年雄性大鼠 松质骨以骨重建活动为主,仍有骨建造活动。PGE2主要通过刺激成骨细胞骨建造而增加骨量。 相似文献
25.
MJ Hwang A Bhangu CE Webster DM Bowley MX Gannon SS Karandikar 《Annals of the Royal College of Surgeons of England》2014,96(5):343-347
Introduction
In 2009 the Department of Health instructed McKinsey & Company to provide advice on how commissioners might achieve world class National Health Service productivity. Asymptomatic inguinal hernia repair was identified as a potentially cosmetic procedure, with limited clinical benefit. The Birmingham and Solihull primary care trust cluster introduced a policy of watchful waiting for asymptomatic inguinal hernia, which was implemented across the health economy in December 2010. This retrospective cohort study aimed to examine the effect of a change in clinical commissioning policy concerning elective surgical repair of asymptomatic inguinal hernias.Methods
A total of 1,032 patients undergoing inguinal hernia repair in the 16 months after the policy change were compared with 978 patients in the 16 months before. The main outcome measure was relative proportion of emergency repair in groups before and after the policy change. Multivariate binary logistic regression was used to adjust the main outcome for age, sex and hernia type.Results
The period after the policy change was associated with 59% higher odds of emergency repair (3.6% vs 5.5%, adjusted odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.03–2.47). In turn, emergency repair was associated with higher odds of adverse events (4.7% vs 18.5%, adjusted OR: 3.68, 95% CI: 2.04–6.63) and mortality (0.1% vs 5.4%, p<0.001, Fisher’s exact test).Conclusions
Introduction of a watchful waiting policy for asymptomatic inguinal hernias was associated with a significant increase in need for emergency repair, which was in turn associated with an increased risk of adverse events. Current policies may be placing patients at risk. 相似文献26.
Simone F. Nery Sara P.C. Paiva rica L. Vieira Andressa B. Barbosa Edna M. Sant'Anna Maira Casalechi Cynthia Dela Cruz Antnio L. Teixeira Fernando M. Reis 《Stress and health》2019,35(1):49-58
Infertile women often experience chronic stress, which may have a negative impact on general well‐being and may increase the burden of infertility. In this open‐label, parallel, randomized controlled trial, infertile women aged 18–50 years (median 37 years) were assigned to an 8‐week mindfulness‐based program (MBP) or no intervention. The primary outcome was stress severity measured by the Lipp's Stress Symptoms Inventory (ISSL). Data were analyzed by modified intent‐to‐treat principle, which included all cases available to follow‐up regardless of adherence to the intervention (62 participants from the MBP group and 37 from the control group). The median number of symptoms of chronic stress recorded in the past month decreased from six (interquartile range 2 to 9) before the MBP to two (interquartile range 1 to 4) after the intervention (p < 0.001, repeated measures analysis of variance with Time × Group interaction). Depressive symptoms also decreased after MBP, whereas general well‐being improved (p < 0.01 for both outcomes). Hair cortisol and serum brain‐derived neurotrophic factor (BDNF) did not change significantly between preintervention and postintervention. None of the outcomes changed significantly in the control group. MBP was effective in reducing stress and depressive symptoms while increasing general well‐being in infertile women. 相似文献
27.
Sarah Alves Auharek Carlos Alexandre Carollo Rodrigo Juliano Oliveira Andra Luiza Cunha‐Laura Antnio Carlos Duenhas Monreal Joo Mximo Siqueira Deiler Sampaio Costa Tammy Reis de Paiva Cond Dayhanne Isa Langkammer Wollf Ernani Aloysio Amaral 《Andrologia》2019,51(8)
Pfaffia glomerata (Spreng.) Pedersen, popularly known as “Brazilian ginseng,” is used as medicinal plant in Brazil to treat inflammatory diseases in general. Previous studies showed that its extract increases the nitric oxide (NO) levels. Knowing that NO downregulates steroidogenesis and that alterations in the action/production of androgens during perinatal life could alter testis development, the present studies sought to investigate the reproductive toxicity of Pfaffia glomerata on male mice exposed to hydroalcoholic extract in utero and during lactation. The present study shows that P. glomerata extract does not alter body weight, tubular diameter and testis function in male mice. Although a reduction in the testis weight was observed in the animals that received the highest dose directly in early post‐natal life, our findings show clearly that P. glomerata may not act as an endocrine disruptor, and it is not an “antiandrogenic” compound that could lead to testicular dysgenesis syndrome. 相似文献
28.
29.
30.
Reversible oxidant-induced increases in albumin transfer across cultured endothelium: alterations in cell shape and calcium homeostasis 总被引:20,自引:0,他引:20
To determine whether reactive oxygen molecules could directly and reversibly increase the transfer of albumin across an endothelial barrier, we measured albumin transfer across monolayers of endothelium cultured on micropore filters before and after exposure to xanthine and xanthine oxidase. Xanthine and xanthine oxidase increased endothelial albumin transfer in a dose-dependent fashion. Parallel phase contrast and fluorescence microscopy demonstrated retraction of adjacent cells from one another and disruption of the actin filaments. The oxidant- induced increases in albumin transfer and changes in cell shape were reversed by removing xanthine oxidase and then incubating the monolayers for 3 1/2 hours in tissue culture media enriched with fetal bovine serum. However, incubation in tissue culture media without serum resulted in progressive injury and cell death. Hence, the brief exposure to oxidants initiated a progressive injury process that was reversed by incubation in serum. Because intracellular and extracellular calcium are important determinants of cell shape, and because some oxidized membrane lipids act as calcium ionophores, we asked whether oxidants altered endothelial calcium homeostasis. Xanthine-xanthine oxidase increased release of 45Ca++ from preloaded cells. The calcium antagonist lanthanum chloride prevented xanthine- xanthine oxidase increases in endothelial albumin transfer and prevented the changes in cell shape; chelation of extracellular calcium inhibited lysis of endothelium by xanthine-xanthine oxidase; and the calcium ionophore A23187 increased endothelial albumin transfer and mimicked the oxidant-induced changes in cell shape. Lanthanum chloride inhibited these effects of A23187. These data suggest that oxygen radicals can reversibly increase endothelial permeability to macromolecules, that this is associated with reversible changes in endothelial cell shape and actin filaments, and that the changes in cell shape are related to oxidant-induced changes in endothelial calcium homeostasis. 相似文献