全文获取类型
收费全文 | 348篇 |
免费 | 12篇 |
国内免费 | 15篇 |
专业分类
儿科学 | 15篇 |
基础医学 | 22篇 |
口腔科学 | 4篇 |
临床医学 | 34篇 |
内科学 | 57篇 |
皮肤病学 | 4篇 |
神经病学 | 12篇 |
特种医学 | 106篇 |
外科学 | 15篇 |
综合类 | 15篇 |
预防医学 | 10篇 |
眼科学 | 11篇 |
药学 | 25篇 |
中国医学 | 31篇 |
肿瘤学 | 14篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 2篇 |
2011年 | 7篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 7篇 |
2007年 | 17篇 |
2006年 | 18篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 8篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 21篇 |
1997年 | 19篇 |
1996年 | 27篇 |
1995年 | 14篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 13篇 |
1988年 | 22篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 3篇 |
排序方式: 共有375条查询结果,搜索用时 15 毫秒
81.
Introduction: Temporary GES (tempGES) can improve both gastric emptying and symptoms in post-surgical gastroparesis (PS-GP). (SSAT 2004). Long-term effects on GI symptoms and gastric emptying are unknown. Since many PS-GP patients have non-delayed emptying, the long-term effect on baseline normal or rapid emptying is also unknown.
Patients: 36 pts (6 M, 30 F, mean age 42 years) with post-surgical: Bilroth I ( n = 11), Bilroth II ( n = 4), other gastric surgery ( n = 21) disordered gastric emptying were evaluated.
Methods: GI symptoms (vomiting = V, Total = TSS), and solid meal gastric emptying (GET) at 1 and 4 h, were compared at baseline (Base), after temporary (tempGES) and permanent (permGES) gastric electrical stimulation as previously described (NGM, 2004; 16: 635.) Long-term follow-up for permanent GES ranged from 6 month to 10 years. Results were compared by t-tests, and are reported as means ± SEM.
Results: 29 of the 36 patients were able to tolerate food for baseline quantitative gastric emptying testing. 20 patients had delayed and 9 patients had non-delayed gastric emptying, with 7/9 being rapid. With both tempGES and permGES, GI symptoms improved (p < 0.05). Both tempGES and permGES showed accelerated GET for delayed patients and generally slowed GET for non-delayed (p < 0.05 for 1 h values). See tables below.
Conclusions: In a large group of post-surgical GP patients, temporary and permanent gastrointestinal electrical stimulation improved GI symptoms independent of gastric emptying and for a prolonged time. GES improves symptoms independent of baseline gastric emptying, and improves GET dependent on the baseline gastric emptying.
Patients: 36 pts (6 M, 30 F, mean age 42 years) with post-surgical: Bilroth I ( n = 11), Bilroth II ( n = 4), other gastric surgery ( n = 21) disordered gastric emptying were evaluated.
Methods: GI symptoms (vomiting = V, Total = TSS), and solid meal gastric emptying (GET) at 1 and 4 h, were compared at baseline (Base), after temporary (tempGES) and permanent (permGES) gastric electrical stimulation as previously described (NGM, 2004; 16: 635.) Long-term follow-up for permanent GES ranged from 6 month to 10 years. Results were compared by t-tests, and are reported as means ± SEM.
Results: 29 of the 36 patients were able to tolerate food for baseline quantitative gastric emptying testing. 20 patients had delayed and 9 patients had non-delayed gastric emptying, with 7/9 being rapid. With both tempGES and permGES, GI symptoms improved (p < 0.05). Both tempGES and permGES showed accelerated GET for delayed patients and generally slowed GET for non-delayed (p < 0.05 for 1 h values). See tables below.
Conclusions: In a large group of post-surgical GP patients, temporary and permanent gastrointestinal electrical stimulation improved GI symptoms independent of gastric emptying and for a prolonged time. GES improves symptoms independent of baseline gastric emptying, and improves GET dependent on the baseline gastric emptying.
82.
83.
Comparative performance of playground surfacing materials including conditions of extreme non-compliance 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《Injury prevention》网站下载免费的PDF全文](/ch/ext_images/free.gif)
OBJECTIVE: A recent case series study found that only 4.7% of 402 playgrounds in which arm fractures occurred in Victorian schools complied with the recommended 20 cm depth of tanbark. Tanbark depths at fall sites varied between 0-27 cm and the mean was 11.1 (5.0) cm. The purposes of the present study were to (1) measure impact attenuation properties of shallow and compacted depths of tanbark; (2) validate laboratory measurements with in situ data; (3) compare impact attenuation properties of compacted tanbark with an Australian manufactured rubber based surface material; and (4) study the impact performance of rubber and tanbark hybrid surfacing. METHODS: A standard test headform was dropped on tanbark and rubber surfaces in a laboratory setting to measure peak impact deceleration and head injury criterion (HIC) values. Variations in surface depth ranged from 2 cm-20 cm (tanbark) and 2 cm-9 cm (rubber). Drop height ranged from 0.5 m-2.5 m. RESULTS: Peak deceleration and HIC increased with increasing drop height and decreasing surface depth. Laboratory measurements at depths less than 8 cm overestimated peak deceleration and HIC values compared with in situ playground measurements. Impact attenuation of a 9 cm thick bilaminate rubber material was comparable to that of an 18 cm depth of compacted tanbark. Rubber-tanbark hybrid surfaces showed improved impact attenuation over individual surfaces. CONCLUSIONS: Compacted tanbark of depth less than 8 cm is ineffective in attenuating playground falls, resulting in excessive impact deceleration and HIC values. Shallow and compacted tanbark found in many Victorian school playgrounds poses a high risk for severe head injury. This calls for stricter enforcement of playground surface depth compliance. 相似文献
84.
Bioassay-guided fractionation of an MeCOEt extract of Frullania nisquallensis Sull. has furnished a DNA-damaging sesquiterpene, costunolide (1), and two inactive compounds, a sesquiterpene (-)-frullanolide (2) and a tridepside tenuiorin (3). (13)C-NMR data of 3 are reported. 相似文献
85.
AIM:To isolate and characterize solid tumor inhibitory and other constituents from a bioactive extract of Casimiroa tetrameria((Rutaceae).METHODS:A crude extract of C.tetrameria obtained from the US National Cancer Institute Natural Product Repository and found to exhibit selective toxicity to solid tumor cells was subjected bioactivity-guided fractionation involving solvent-solvent partitioning,gel filtration,and chromatography.The structures of all isolated compounds were elucidated by spectroscopic analy... 相似文献
86.
Gestational exposure to chlorpyrifos: dose response profiles for cholinesterase and carboxylesterase activity 总被引:3,自引:2,他引:1
This study investigates the in vivo dose response profiles of the target
enzyme cholinesterase (ChE) and the detoxifying enzymes carboxylesterase
(CaE) in the fetal and maternal compartments of pregnant rats dosed with
chlorpyrifos [(O,O'-diethyl O-3,5,6-trichloro- 2-pyridyl)
phosphorothionate], a commonly used organophosphorus insecticide. Pregnant
rats were dosed daily (po) with chlorpyrifos in corn oil (0, 3, 5, 7, or 10
mg/kg) on gestational days (GD) 14-18. Animals were sacrificed 5 h after
the last chlorpyrifos dose (time of maximum brain cholinesterase
inhibition) for analysis of ChE and CaE activity in maternal blood, liver,
brain, placenta, and fetal liver and brain. The in vitro sensitivity (i.e.,
IC50, 30 min, 26 degrees C) of CaE also was determined by assaying the
activity remaining after incubation with a range of chlorpyrifos-oxon
concentrations. In vivo exposure to 10 mg/kg chlorpyrifos from GD14-18
caused overt maternal toxicity, with dose-related decreases in ChE activity
more notable in maternal brain than fetal brain. Dose-related effects were
also seen with chlorpyrifos-induced inhibition of fetal liver ChE and
maternal brain CaE activities. Gestational exposure caused no inhibition of
placental ChE or CaE, fetal brain CaE, or maternal blood CaE. ChE
activities in the maternal blood and liver, as well as fetal and maternal
liver CaE, however, were maximally inhibited by even the lowest dosage of
chlorpyrifos. The in vitro sensitivity profiles of CaE to chlorpyrifos-oxon
inhibition were valuable in predicting and verifying the in vivo CaE
response profiles. Both the in vivo and in vitro findings indicated that
fetal liver CaE inhibition was an extremely sensitive indicator of fetal
chlorpyrifos exposure.
相似文献
87.
KL Cassidy GJ Reid PJ McGrath DJ Smith TL Brown GA Finley 《Acta paediatrica (Oslo, Norway : 1992)》2001,90(11):1329-1336
The effectiveness of a eutectic mixture lidocaine-prilocaine topical anaesthetic cream (EMLA) patch compared with a placebo patch in the reduction of pain associated with intramuscular immunization was evaluated. As part of the study, 161 children (aged 4-6-y) undergoing routine diphtheria, pertussis, tetanus and polio (DPTP) immunization in five urban and five rural private office settings were randomly assigned to an EMLA patch (n = 83) or a placebo patch control group (n = 78). Pain measurements included: child's self-report on a Faces Pain Scale; facial action on the Child Facial Coding System; the Children's Hospital of Eastern Ontario Pain Scale and parent and technician ratings on a Visual Analogue Scale. Parents also rated their own and their child's immunization-related anxiety on a Visual Analogue Scale. The EMLA patch group had significantly less pain on all four pain measures compared with the placebo group. Of the children in the placebo group, 43% had clinically significant pain, compared with 17% of children in the EMLA patch group. No severe adverse symptoms occurred as a result of either EMLA or placebo patch application. CONCLUSION: The EMLA patch reduced immunization pain in 4 to 6-y-old children during needle injection. 相似文献
88.
Incidence of cervical dysplasia and cervical cancer in women living with HIV in Denmark: comparison with the general population
下载免费PDF全文
![点击此处可从《HIV medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
89.
In vivo and in vitro MR imaging of renal tumors: histopathologic correlation and pulse sequence optimization 总被引:1,自引:0,他引:1
Quint LE; Glazer GM; Chenevert TL; Fechner KP; Gikas PW; Shireman PK; Grossman HB; Li KC 《Radiology》1988,169(2):359-362
Magnetic resonance (MR) imaging has given mixed results in the detection of renal masses. To identify the reasons for this and to determine the optimal pulse sequences for evaluating renal tumors, the authors imaged 12 primary renal tumors in vivo and 17 in vitro at 0.35 T. Histopathologic findings for each specimen were closely correlated with the MR images. Four of seven solid tumors imaged in vivo were isointense with surrounding normal renal parenchyma at all pulse sequences. The other three tumors were hyperintense in vivo at T2-weighted sequences. At heavily T2-weighted sequences eight solid tumors were hyperintense in vitro and four were hypointense. There was no correlation between signal intensity and specific tissue type or histologic pattern for solid tumors. The five cystic tumors were well seen both in vivo and in vitro on T2-weighted images. However, the signal intensity of the cyst fluid was an unreliable indicator of benignancy. SE MR imaging at 0.35 T has significant limitations in the detection of solid renal masses. 相似文献
90.
TL Economopoulos PA Asvestas GK Matsopoulos K Gr?ndahl H-G Gr?ndahl 《Dento maxillo facial radiology》2010,39(5):300-313
Contrast correction is often required in digital subtraction radiography when comparing medical data acquired over different time periods owing to dissimilarities in the acquisition process. This paper focuses on dental radiographs and introduces a novel approach for correcting the contrast in dental image pairs.The proposed method modifies the subject images by applying typical registration techniques on their histograms. The proposed histogram registration method reshapes the histograms of the two subject images in such a way that these images are matched in terms of their contrast deviation. The method was extensively tested over 4 sets of dental images, consisting of 72 registered dental image pairs with unknown contrast differences as well as 20 dental pairs with known contrast differences. The proposed method was directly compared against the well-known histogram-based contrast correction method.The two methods were qualitatively and quantitatively evaluated for all 92 available dental image pairs. The two methods were compared in terms of the contrast root mean square difference between the reference image and the corrected image in each case. The obtained results were also verified statistically using appropriate t-tests in each set.The proposed method exhibited superior performance compared with the well-established method, in terms of the contrast root mean square difference between the reference and the corrected images. After suitable statistical analysis, it was deduced that the performance advantage of the proposed approach was statistically significant. 相似文献