全文获取类型
收费全文 | 1559篇 |
免费 | 103篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 34篇 |
妇产科学 | 18篇 |
基础医学 | 310篇 |
口腔科学 | 30篇 |
临床医学 | 114篇 |
内科学 | 363篇 |
皮肤病学 | 29篇 |
神经病学 | 171篇 |
特种医学 | 60篇 |
外科学 | 144篇 |
综合类 | 2篇 |
一般理论 | 2篇 |
预防医学 | 96篇 |
眼科学 | 24篇 |
药学 | 113篇 |
中国医学 | 9篇 |
肿瘤学 | 160篇 |
出版年
2024年 | 1篇 |
2023年 | 19篇 |
2022年 | 52篇 |
2021年 | 68篇 |
2020年 | 29篇 |
2019年 | 50篇 |
2018年 | 69篇 |
2017年 | 46篇 |
2016年 | 59篇 |
2015年 | 68篇 |
2014年 | 88篇 |
2013年 | 88篇 |
2012年 | 143篇 |
2011年 | 145篇 |
2010年 | 70篇 |
2009年 | 74篇 |
2008年 | 119篇 |
2007年 | 89篇 |
2006年 | 86篇 |
2005年 | 74篇 |
2004年 | 67篇 |
2003年 | 66篇 |
2002年 | 54篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1980年 | 3篇 |
排序方式: 共有1683条查询结果,搜索用时 15 毫秒
71.
Baldissera F Rota V Esposti R 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,190(3):289-305
The hypothesis that anticipatory postural adjustments (APAs) may concur in generating the directional preference experienced
during limb coupled movements was tested by measuring the electromyographic and mechanic postural actions elicited when moving:
(1) one single arm/hand and, (2) both limbs, iso- or antidirectionally coupled. During fast adduction of the right arm in
the horizontal plane (prime mover, pectoralis Major, rPM) APAs were recorded in the contralateral lPM as well as in the right ischiocruralis (rIC) muscle. This last action was associated to a transient increase of Tz (torque around body vertical axis) in the direction
opposite to arm rotation. Both the APAs in rIC and the Tz changes nearly doubled in size when arms were coupled isodirectionally (adduction of one arm and abduction on the other) while they vanished when both arms were simultaneously adducted (antidirectional coupling). Conformably, during rhythmic arm oscillations APAs and Tz were cyclically modulated when movements were isodirectional, the modulation amplitude being strongly enhanced by increasing the movement frequency. When oscillations were antidirectional neither APAs nor Tz changes were observed, even if frequency was incremented. The postural actions linked to unidirectional
or cyclic movements of the hand were affected by either coupling or frequency in the same way as arm movements, albeit much
smaller in size. In conclusion, during antidirectional movements APAs in prime movers are synergic with voluntary activation and no postural engagement is requested to leg muscles.
Conversely, during isodirectional movements, APAs in prime movers conflict with the voluntary commands and a strong, frequency-dependent, postural effort is
required to leg muscles. How these factors may co-operate in determining the preference for antidirectional coupling is discussed. 相似文献
72.
O'Connor GM Seich Al Basatena NK Olavarria V MacNamara A Vine A Ying Q Hisada M Galvão-Castro B Asquith B McVicar DW 《Human immunology》2012,73(8):783-787
While most carriers of human T-cell leukemia virus type 1 (HTLV-1) remain asymptomatic throughout their lifetime, infection is associated with the development of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The exact parameters that determine these outcomes are unknown but are believed to include host genetic factors that control the immune response to infection. Host response to fellow retroviridae member HIV is influenced by the expression of members of the Killer Immunoglobulin Receptor (KIR) family including KIR3DS1. In this study we examined the association of KIR3DS1 with the outcome of HTLV-1 infection in three geographically distinct cohorts (Jamaican, Japanese and Brazilian). Despite increased prevalence of KIR3DS1 in the HAM/TSP patients of the Jamaican cohort, we found no evidence for a role of KIR3DS1 in influencing control of proviral load or disease outcome. This suggests that unlike HIV, KIR3DS1-mediated regulation of HTLV-1 infection does not occur, or is ineffective. 相似文献
73.
Marin-Esteban V Turbica I Dufour G Semiramoth N Gleizes A Gorges R Beau I Servin AL Lievin-Le Moal V Sandré C Chollet-Martin S 《Infection and immunity》2012,80(5):1891-1899
We recently documented the neutrophil response to enterovirulent diffusely adherent Escherichia coli expressing Afa/Dr fimbriae (Afa/Dr DAEC), using the human myeloid cell line PLB-985 differentiated into fully mature neutrophils. Upon activation, particularly during infections, neutrophils release neutrophil extracellular traps (NETs), composed of a nuclear DNA backbone associated with antimicrobial peptides, histones, and proteases, which entrap and kill pathogens. Here, using fluorescence microscopy and field emission scanning electron microscopy, we observed NET production by PLB-985 cells infected with the Afa/Dr wild-type (WT) E. coli strain C1845. We found that these NETs were able to capture, immobilize, and kill WT C1845 bacteria. We also developed a coculture model of human enterocyte-like Caco-2/TC7 cells and PLB-985 cells previously treated with WT C1845 and found, for the first time, that the F-actin cytoskeleton of enterocyte-like cells is damaged in the presence of bacterium-induced NETs and that this deleterious effect is prevented by inhibition of protease release. These findings provide new insights into the neutrophil response to bacterial infection via the production of bactericidal NETs and suggest that NETs may damage the intestinal epithelium, particularly in situations such as inflammatory bowel diseases. 相似文献
74.
Goñi N Moratorio G Ramas V Coppola L Chiparelli H Cristina J 《Archives of virology》2011,156(1):87-94
The first influenza pandemic of this century was declared in April of 2009, with the emergence of a novel H1N1 influenza A
virus strain (H1N1pdm). Understanding the evolution of H1N1pdm strains within the South American region is essential for studying
global diversification, emergence and resistance, as well as determining vaccine efficacy. In order to gain insight into these
matters, phylogenetic analysis was performed using 29 hemagglutinin (HA) gene sequences from H1N1pdm strains isolated in South
America. The results of these studies revealed that clade 7 was the dominant H1N1pdm lineage in South America. None of the
strains isolated in South America clustered together with the 2010 H1 vaccine strain. Amino acid substitutions P100S, S220T
and I338V were found in almost all HAs of South American H1N1pdm strains. 相似文献
75.
Verónica Bisagno Mariana Raineri Viviana Peskin Silvia I. Wikinski Osvaldo D. Uchitel Rodolfo R. Llinás Francisco J. Urbano 《Psychopharmacology》2010,212(2):205-214
Rationale
Repetitive cocaine exposure has been shown to induce GABAergic thalamic alterations. Given the key role of T-type (CaV3) calcium channels in thalamocortical physiology, the direct involvement of these calcium channels in cocaine-mediated effects needs to be further explored. 相似文献76.
Perry T.C. van Doormaal Kevin Kenna Frank P. Diekstra Federico Verde Peter M. Andersen Annelot M. Dekker Cinzia Tiloca Nicolai Marroquin Daniel J. Overste Viviana Pensato Peter Nürnberg Sara L. Pulit Raymond D. Schellevis Daniela Calini Janine Altmüller Laurent C. Francioli Bernard Muller Barbara Castellotti Susanne Motameny Antonia Ratti Joachim Wolf Cinzia Gellera Albert C. Ludolph Leonard H. van den Berg Christian Kubisch Alexander E. Volk 《Human mutation》2017,38(11):1534-1541
The genetic basis combined with the sporadic occurrence of amyotrophic lateral sclerosis (ALS) suggests a role of de novo mutations in disease pathogenesis. Previous studies provided some evidence for this hypothesis; however, results were conflicting: no genes with recurrent occurring de novo mutations were identified and different pathways were postulated. In this study, we analyzed whole‐exome data from 82 new patient‐parents trios and combined it with the datasets of all previously published ALS trios (173 trios in total). The per patient de novo rate was not higher than expected based on the general population (P = 0.40). We showed that these mutations are not part of the previously postulated pathways, and gene–gene interaction analysis found no enrichment of interacting genes in this group (P = 0.57). Also, we were able to show that the de novo mutations in ALS patients are located in genes already prone for de novo mutations (P < 1 × 10‐15). Although the individual effect of rare de novo mutations in specific genes could not be assessed, our results indicate that, in contrast to previous hypothesis, de novo mutations in general do not impose a major burden on ALS risk. 相似文献
77.
Alicia Lagarto Addis Bellma Micaela Couret Tatiana Gabilondo Raisel López Viviana Bueno Isbel Guerra Jorge Rodríguez 《Experimental and toxicologic pathology》2013,65(1-2):49-53
The potential of oral exposure to calcium and magnesium citrate, a natural product obtained from dolomite, to initiate teratogenesis was analyzed in Wistar rats. Animals received calcium and magnesium citrate oral doses of 250, 500 and 1000 mg/kg during the period of gestation from day 6 to 17 post conception. Maternal, embryo and fetal toxicity was evaluated. Calcium and magnesium citrate exposure did not produce maternal toxicity assessed by clinical observations, body weight gain, food intake, hematology, biochemical parameters and necropsy finding. Signs of embryo–fetal toxicity were not observed. Skeletal and visceral malformations were seen occasionally in all drug-treated and control groups. Skeletal and visceral variations were similar in control and drug-treated groups except for incomplete ossification rib. These finding was spontaneous and unrelated to the drug. In conclusion, in this study we found that the oral exposure to rats of up to 1000 mg/kg of calcium and magnesium citrate during organogenesis did not induce significant maternal and embryo–fetal toxicity. The experimentally derived NOAEL for developmental toxicity was 1000 mg/kg. 相似文献
78.
Sexual dimorphism (SD) represents all the differences between males and females of the same species. SD of the murine lacrimal gland and the major effect of testosterone on its formation are well documented. Steroidogenic factor-1 (SF-1, NR5a1) is a nuclear receptor essential for the fetal development of steroid hormones producing organs and SF-1 knockout mice (Sf-1 KO) are therefore born without gonads and adrenal glands. The aim of this study was to investigate whether SD in lacrimal glands is present in the absence of exposure to sex hormones during development. Lacrimal glands from adult Sf-1 KO male and female mice without hormonal exposure, and from males that were treated with testosterone propionate (TP) prior to sacrifice, were examined. After sacrifice, glandular tissue was processed using standard histological procedures. Paraffin sections were analysed by stereology and immunostained against the androgen receptor (AR). Our results showed that there were no statistically significant differences in the mean volumes of acini, connective tissue or ductal system between males, females, and males on TP. The same pertains to the mean length of the ducts in all three groups. In the absence of sex hormones, sex chromosomes proved to be insufficient in inducing sexual dimorphism in LG. However, nuclei of the acinar cells in males on TP were positive for AR, whereas in males without TP no expression of AR was detected. Administration of TP induced the expression of AR in the nuclei of acinar cells of males but did not affect the morphology of LG. We conclude that SD in the lacrimal gland is not present in Sf-1 KO mice and this suggests that sex hormones have a major role in the development of SD in the lacrimal gland. 相似文献
79.
Farías A Cabrerizo M Ré V Glatstein N Pisano B Spinsanti L Contigiani MS 《Archives of virology》2011,156(1):129-133
In the central area of Argentina, epidemiological and molecular characteristics of human enterovirus infections are still
unknown. RT-nested PCR of the highly conserved 5′NCR was used to detect enteroviruses in 168 samples of cerebrospinal fluid
from hospitalized patients with suspected infection of the central nervous system (2007–2008), and 13 (7.7%) were positive.
Molecular typing was performed by sequencing of the 3′-half VP1 region. Echovirus 30 was the predominant type detected, followed
by coxsackie viruses A9 and B4. All echovirus 30 strains of 2007 clustered in lineage H, whereas the echovirus 30 isolate
obtained in 2008 was more distantly related, possibly representing a new lineage. 相似文献
80.
Jean-François Desaphy Sabata Pierno Antonella Liantonio Viviana Giannuzzi Claudio Digennaro Maria Maddalena Dinardo Giulia M. Camerino Patrizia Ricciuti Lorenza Brocca Maria Antonietta Pellegrino Roberto Bottinelli Diana Conte Camerino 《Pharmacological research》2010,61(6):553-563
Oxidative stress was proposed as a trigger of muscle impairment in various muscle diseases. The hindlimb-unloaded (HU) rodent is a model of disuse inducing atrophy and slow-to-fast transition of postural muscles. Here, mice unloaded for 14 days were chronically treated with the selective antioxidant trolox. After HU, atrophy was more pronounced in the slow-twitch soleus muscle (Sol) than in the fast-twitch gastrocnemius and tibialis anterior muscles, and was absent in extensor digitorum longus muscle. In accord with the phenotype transition, HU Sol showed a reduced expression of myosin heavy chain type 2A (MHC-2A) and increase in MHC-2X and MHC-2B isoforms. In parallel, HU Sol displayed an increased sarcolemma chloride conductance related to an increased expression of ClC-1 channels, changes in excitability parameters, a positive shift of the mechanical threshold, and a decrease of the resting cytosolic calcium concentration. Moreover, the level of lipoperoxidation increased proportionally to the degree of atrophy of each muscle type. As expected, trolox treatment fully prevented oxidative stress in HU mice. Atrophy was not prevented but the drug significantly attenuated Sol phenotypic transition and excitability changes. Trolox treatment had no effect on control mice. These results suggest possible benefits of antioxidants in protecting muscle against disuse. 相似文献