全文获取类型
收费全文 | 2510篇 |
免费 | 162篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 158篇 |
妇产科学 | 34篇 |
基础医学 | 306篇 |
口腔科学 | 124篇 |
临床医学 | 217篇 |
内科学 | 588篇 |
皮肤病学 | 50篇 |
神经病学 | 189篇 |
特种医学 | 350篇 |
外科学 | 186篇 |
综合类 | 23篇 |
预防医学 | 121篇 |
眼科学 | 26篇 |
药学 | 201篇 |
1篇 | |
中国医学 | 7篇 |
肿瘤学 | 118篇 |
出版年
2023年 | 20篇 |
2022年 | 41篇 |
2021年 | 95篇 |
2020年 | 44篇 |
2019年 | 67篇 |
2018年 | 82篇 |
2017年 | 60篇 |
2016年 | 63篇 |
2015年 | 68篇 |
2014年 | 79篇 |
2013年 | 132篇 |
2012年 | 106篇 |
2011年 | 104篇 |
2010年 | 94篇 |
2009年 | 110篇 |
2008年 | 69篇 |
2007年 | 73篇 |
2006年 | 77篇 |
2005年 | 68篇 |
2004年 | 59篇 |
2003年 | 65篇 |
2002年 | 43篇 |
2001年 | 30篇 |
2000年 | 24篇 |
1999年 | 36篇 |
1998年 | 102篇 |
1997年 | 118篇 |
1996年 | 115篇 |
1995年 | 79篇 |
1994年 | 82篇 |
1993年 | 98篇 |
1992年 | 18篇 |
1991年 | 20篇 |
1990年 | 19篇 |
1989年 | 47篇 |
1988年 | 42篇 |
1987年 | 26篇 |
1986年 | 32篇 |
1985年 | 31篇 |
1984年 | 18篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 34篇 |
1980年 | 23篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 21篇 |
1976年 | 19篇 |
1975年 | 6篇 |
1970年 | 1篇 |
排序方式: 共有2711条查询结果,搜索用时 62 毫秒
101.
Background
The ethnic usage of exotics and indigenous problem plants is a highly debated topic, as legislative requirements over-shadow their potential medicinal value, particularly to treat sexually transmitted infections (STIs). Limited information exists regarding their medicinal value among the Bapedi.Objectives
To ascertain the importance of exotics and indigenous problem plants in the treatment of STIs, a major global primary health care challenge.Methods
A field observation and semi-structured questionnaire focussing on species diversity, types of STIs treated and medicinal preparation as well as application was used to collect data from 34 traditional healers.Results
Seven exotics and three indigenous problem species were identified. These species were used to treat four STIs; with Catharanthus roseus illustrating its dominance in the treatment of gonorrhoea. Some medicinal species used by Bapedi traditional healers have been validated through scientific research or through their extensive use by various cultures in South Africa and other parts of Africa. To the best of our knowledge Alternanthera pungens, Caesalpinia decapetala, Cinnamomum verum, and Citrullus lanatus are reported for the first time in the treatment of the investigated STIs.Conclusions
Exotic and indigenous problem species constitute an important component of the STIs treatment protocol. Their utilization by Bapedi cautions against the narrow-minded approach of indiscriminate eradication, as these species can play a significant role in the primary health care needs of socio-economic vulnerable people. 相似文献102.
PAG Torrie A Leonidou IJ Harding G Wynne Jones MJ Hutchinson IW Nelson 《Annals of the Royal College of Surgeons of England》2013,95(8):604-608
Introduction
The purpose of this study was to investigate the significance of the inflammatory markers on admission in the isolation of a causative pathogen in patients with spinal infection. Spinal infection is treated frequently at spinal units and can encompass a broad range of clinical entities. Its diagnosis is often delayed because of the difficulty of identifying the responsible pathogen.Methods
Patients with spinal infection treated in our institution over a period of eight years were identified and their notes studied retrospectively. Admission C-reactive protein (CRP), white cell count (WCC) as well as co-morbidities and mode of pathogen identification were recorded. Overall, 96 patients were included in the study.Results
The CRP levels on admission were correlated significantly with the overall potential for isolation of a pathogen (p<0.0001) and positive biopsy cultures (p=0.0016). Admission WCC levels were associated significantly with the overall potential for isolation of a pathogen (p=0.0003) and positive biopsy cultures (p=0.0023). Both CRP and WCC levels were significantly negatively correlated with the duration of the preceding symptoms (p=0.0003 and p<0.0001 respectively). Delay in presentation was significantly negatively correlated with organism isolation (p=0.0001). Multivariate analyses identified the delay in presentation as the strongest independent variable for organism isolation (p=0.014) in cases of spontaneous spinal infection when compared with the admission CRP level (p=0.031) and WCC (p=0.056).Conclusions
In spontaneous spinal infection, delay in presentation is the strongest independent variable for organism isolation. High inflammatory marker levels on admission are a useful prognostic marker for the overall potential of isolating a causative organism either by blood cultures or by biopsy in patients with negative blood cultures. Furthermore, the admission inflammatory marker levels allow for treating surgeons to counsel their patients of the likelihood of achieving a positive microbiological yield from biopsy. 相似文献103.
104.
105.
Diana Costa Camila Cardoso Diogo Luís Maltez da Costa José Eduardo Pereira Vítor Filipe Pedro Alexandre Couto 《Neurological research》2013,35(11):963-971
ABSTRACTFunctional recovery following general nerve reconstruction is often associated with poor results. Comparing to rat and mice experimental studies, there are much fewer investigations on nerve regeneration and repair in the sheep, and there are no studies on this subject using gait analysis in the sheep model as an assessment tool. Additionally, this is the first study evaluating obstacle negotiation and the compensatory strategies that take place at each joint in response to the obstacle during locomotion in the sheep model. This study aims to get kinematic data to serve as a template for an objective assessment of the ankle joint motion in future studies of common peroneal nerve (CP) injury and repair in the ovine model. Our results show that a moderately high obstacle set to 10% of the sheep’s hindlimb length was associated to several spatial and temporal strategies in order to increase hoof height during obstacle negotiating. Sheep efficiently cleared an obstacle by increasing knee, ankle and metatarsophalangeal flexion during swing, whereas the hip joint is not affected. This study establishes the bounds of normal motion in the neurologically intact hindlimb when approached and cleared an obstacle and provides baseline data for further studies of peripheral nerve research in the ovine model. 相似文献
106.
107.
Amanda V. Steckert Clarissa M. Comim Francielle Mina Bruna P. Mendonça Diogo Dominguini Gabriela K. Ferreira Milena Carvalho‐Silva Júlia S. Vieira Emilio L. Streck João Quevedo Felipe Dal‐Pizzol 《Synapse (New York, N.Y.)》2013,67(11):786-793
Central nervous system (CNS) dysfunction secondary to sepsis is characterized by long‐term cognitive impairment. It was observed that oxidative damage, energetic metabolism impairment, and cytokine level alteration seen in early times in an animal model of sepsis may persist for up to 10 days and might be associated with cognitive damage. In order to understand these mechanisms, at least in part, we evaluated the effects of sepsis on cytokine levels in the cerebrospinal fluid (CSF), oxidative parameters, and energetic metabolism in the brain of rats at both 30 and 60 days after sepsis induction by cecal ligation and perforation (CLP). To this aim, male Wistar rats underwent CLP with “basic support” or were sham‐operated. Both 30 and 60 days after surgery, the CSF was collected and the animals were killed by decapitation. Then, the prefrontal cortex, hippocampus, striatum, and cortex were collected. Thirty days after surgery, an increase of IL‐6 level in the CSF; an increase in the thiobarbituric acid‐reactive species (TBARS) in prefrontal cortex and a decrease in hippocampus, striatum, and cortex; a decrease of carbonyl protein formation only in prefrontal cortex and an increase in striatum; and an increase in the complex IV activity only in hippocampus were observed. Sixty days after sepsis, an increase of TNF‐α level in the CSF; a decrease of TBARS only in hippocampus; an increase of carbonyl protein formation in striatum; and a decrease of complex I activity in prefrontal cortex, hippocampus, and striatum were observed. These findings may contribute to understanding the role of late cognitive impairment. Further studies may address how these findings interact during sepsis development and contribute to CNS dysfunction. Synapse 67:786–793, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
108.
José Gon?alves Pereira Bravo Edson Ide Andre Kondo Diogo Turiani Hourneaux de Moura Eduardo Turiani Hourneaux de Moura Paulo Sakai Wanderley Marques Bernardo Eduardo Guimar?es Hourneaux de Moura 《Clinics (S?o Paulo, Brazil)》2016,71(3):169-178
To compare the complications and mortality related to gastrostomy procedures performed using surgical and percutaneous endoscopic gastrostomy techniques, this review covered seven studies. Five of these were retrospective and two were randomized prospective studies. In total, 406 patients were involved, 232 of whom had undergone percutaneous endoscopic gastrostomy and 174 of whom had undergone surgical gastrostomy. The analysis was performed using Review Manager. Risk differences were computed using a fixed-effects model and forest and funnel plots. Data on risk differences and 95% confidence intervals were obtained using the Mantel-Haenszel test. There was no difference in major complications in retrospective (95% CI (-0.11 to 0.10)) or randomized (95% CI (-0.07 to 0.05)) studies. Regarding minor complications, no difference was found in retrospective studies (95% CI (-00.17 to 0.09)), whereas a difference was observed in randomized studies (95% CI (-0.25 to -0.02)). Separate analyses of retrospective and randomized studies revealed no differences between the methods in relation to mortality and major complications. Moreover, low levels of minor complications were observed among endoscopic procedures in randomized studies, with no difference observed compared with retrospective studies. 相似文献
109.
Maniglia-Ferreira C Gurgel-Filho ED Silva JB Paula RC Feitosa JP Gomes BP Souza-Filho FJ 《Brazilian Oral Research》2007,21(1):29-34
This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also sought to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130 degrees. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130 degrees C causes changes to its chemical structure which permanently alter its physical properties. 相似文献
110.
Proposal of a guanine-based purinergic system in the mammalian central nervous system 总被引:2,自引:0,他引:2
Guanine-based purines have been traditionally studied as modulators of intracellular processes, mainly G-protein activity. However, they also exert several extracellular effects not related to G proteins, including modulation of glutamatergic activity, trophic effects on neural cells, and behavioral effects. In this article, the putative roles of guanine-based purines on the nervous system are reviewed, and we propose a specific guanine-based purinergic system in addition to the well-characterized adenine-based purinergic system. Current evidence suggest that guanine-based purines modulate glutamatergic parameters, such as glutamate uptake by astrocytes and synaptic vesicles, seizures induced by glutamatergic agents, response to ischemia and excitotoxicity, and are able to affect learning, memory and anxiety. Additionally, guanine-based purines have important trophic functions affecting the development, structure, or maintenance of neural cells. Although studies addressing the mechanism of action (receptors and second messenger systems) of guanine-based purines are still insufficient, these findings point to the guanine-based purines (nucleotides and guanosine) as potential new targets for neuroprotection and neuromodulation. 相似文献