全文获取类型
收费全文 | 933篇 |
免费 | 79篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 20篇 |
妇产科学 | 18篇 |
基础医学 | 104篇 |
口腔科学 | 135篇 |
临床医学 | 161篇 |
内科学 | 170篇 |
皮肤病学 | 23篇 |
神经病学 | 83篇 |
特种医学 | 20篇 |
外科学 | 41篇 |
综合类 | 2篇 |
预防医学 | 90篇 |
眼科学 | 10篇 |
药学 | 84篇 |
中国医学 | 1篇 |
肿瘤学 | 47篇 |
出版年
2023年 | 8篇 |
2022年 | 17篇 |
2021年 | 24篇 |
2020年 | 21篇 |
2019年 | 28篇 |
2018年 | 27篇 |
2017年 | 23篇 |
2016年 | 38篇 |
2015年 | 29篇 |
2014年 | 40篇 |
2013年 | 53篇 |
2012年 | 80篇 |
2011年 | 86篇 |
2010年 | 44篇 |
2009年 | 45篇 |
2008年 | 66篇 |
2007年 | 66篇 |
2006年 | 37篇 |
2005年 | 34篇 |
2004年 | 35篇 |
2003年 | 36篇 |
2002年 | 46篇 |
2001年 | 11篇 |
2000年 | 15篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 7篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 1篇 |
排序方式: 共有1016条查询结果,搜索用时 359 毫秒
61.
Background
Both social and ethical arguments have been used to support preventive occupational health services (OHS). During the 1990s it became more common to support political argumentation for occupational health and safety by converting the consequences of ill health at work into monetary units. In addition, OHS has been promoted as a profitable investment for companies, and this aspect has been used by OHS providers in their marketing. 相似文献62.
Ollikainen T Knuuttila A Suhonen S Taavitsainen M Jekunen A Mattson K Linnainmaa K 《Anti-cancer drugs》2000,11(2):93-99
In this study, we used four human mesothelioma cell lines (M14K, M24K, M25K and M38K), one transformed human mesothelial cell line (MeT-5A) and one primary mesothelial culture (UPL) to test for in vitro sensitivity to docetaxel, paclitaxel, SN-38 [an active metabolite of irinotecan (CPT-11)] and gemcitabine, as single agents. Subconfluent cell cultures were treated with 2x10(-9), 5x10(-9), 10(-8), 2x10(-8) and 5x10(-8) M concentrations of each drug for 48 h. The sensitivity was measured in terms of cell viability using the Trypan blue exclusion method. All four drugs were potent inhibitors of mesothelioma cell growth, but cell lines from different patients diverged in their sensitivity to the individual agents. In most cases docetaxel, paclitaxel and SN-38 were more potent killers of mesothelioma cells than gemcitabine. The induction of DNA damage was investigated using the Comet assay; cells from two cell lines (M14K and M25K) were treated with subtoxic 10(-8) M concentrations of each drug for 4, 24 and 48 h. Each of the agents caused a slight increase in DNA single-strand breaks at a concentration of 10(-8) M. 相似文献
63.
The effects of various vehicles, the occlusion time and the concentration of the test substances on the phototoxic reactions were studied using the Finn Chamber method in photoepicutaneous testing, with methoxsalen and coal tar as test substances. Petrolatum proved to be a suitable base for methoxsalen and carbowax for coal tar. The optimal concentration of coal tar was 5% and that of methoxalen 0.03-0.05%. The optimal occlusion time for methoxsalen was 1-2 hours and for coal tar 24 hours. It was concluded that in order to obtain the most reliable results, these parameters should be determined separately for every photosensitizing compound to be tested. 相似文献
64.
BACKGROUND: Deficient dental root development has been reported after conventional pediatric anticancer therapy, but less information is available on stem cell transplantation (SCT) recipients. METHODS: Root-crown (R/C) ratios of fully developed permanent teeth were assessed from panoramic radiographs of 52 SCT recipients, who were treated when they were age < 10 years. Using standard deviation scores (SDSs), the authors compared the R/C ratios to the corresponding tooth and gender-specific values in a healthy population. The percentage of affected R/C ratios per individual was examined in a subgroup of 39 (SG39) patients with advanced tooth development. The effects of total body irradiation (TBI) and SCT age on the R/C ratios were studied in TBI and high-dose chemotherapy (HDC = non-TBI) groups and in 3 age groups (< or = 3.0 years, 3.1-5.0 years, > or = 5.1 years). RESULTS: Per individual, 77% of the fully developed permanent teeth were affected in SG39. At the tooth level, in 77% of the 945 teeth studied (52 patients), the R/C ratios were outside +/-2 SDSs. More teeth were affected in the TBI (85%) than in the non-TBI (55%) group (P < 0.001). The teeth of the patients who were ages 3.1-5.0 years old at SCT presented with the most severe aberrations of the R/C ratio (mean SDS = -4.4) whereas the teeth of the youngest (age < or = 3.0 years) and the oldest (age > or = 5.1 years) patients were equally affected (mean SDSs = -3.1 and -3.0, respectively). CONCLUSIONS: Disturbances of dental root growth always followed pediatric SCT. HDC alone intensely harmed root growth but TBI further increased the adverse effects that were most extensive in the patients 3.1-5.0 years at SCT. These sequelae should be taken into account during the lifelong dental follow-up to minimize the clinical consequences of dental injuries. 相似文献
65.
Experimental phytophotodermatitis was produced using crushed leaves from the gas plant, Dictamnus albus. The tests were made using the chamber method and irradiated with ordinary black light tubes.
An occlusion time of not less than 30 min was needed to give a phototoxic reaction in all test subjects. An occlusion time 30–120 min gave the optimal results, but contact for 24 h produced only weak and inconsistent reactions.
The phototoxic substance was readily absorbed into the skin within 10–15 min. The phototoxic tendency already began to disappear within 30 min after the tests were removed.
UVA energy of 0.3 J/cm2 was enough to evoke a phytophotoreaction in all of the test subjects when other conditions were optimal.
The reactions were enhanced by adding water to the test sites.
Deep-freezing of the plant material did not destroy the phototoxicity within a 4-month period. 相似文献
An occlusion time of not less than 30 min was needed to give a phototoxic reaction in all test subjects. An occlusion time 30–120 min gave the optimal results, but contact for 24 h produced only weak and inconsistent reactions.
The phototoxic substance was readily absorbed into the skin within 10–15 min. The phototoxic tendency already began to disappear within 30 min after the tests were removed.
UVA energy of 0.3 J/cm
The reactions were enhanced by adding water to the test sites.
Deep-freezing of the plant material did not destroy the phototoxicity within a 4-month period. 相似文献
66.
67.
Shared genetic and environmental effects on strength and power in older female twins 总被引:2,自引:0,他引:2
Tiainen K Sipilä S Alén M Heikkinen E Kaprio J Koskenvuo M Tolvanen A Pajala S Rantanen T 《Medicine and science in sports and exercise》2005,37(1):72-78
PURPOSE: This study examined the relative contribution of genetic and environmental effects on maximal leg extensor power and also investigated whether leg extensor power and maximum voluntary isometric knee extensor strength share a genetic component. METHODS: Muscle functions were measured as part of the Finnish Twin Study on Aging in 101 monozygotic (MZ) and 116 dizygotic (DZ) female twin pairs aged 63-76 yr. Leg extensor power was measured using the Nottingham Leg Extensor Power Rig and maximum voluntary isometric knee extensor strength using an adjustable dynamometer chair. The analyses were carried out using the maximum likelihood method in Mx-program on the raw data set. RESULTS: A bivariate Cholesky decomposition model showed that leg extensor power and isometric knee extensor strength shared a genetic component in common, which accounted for 32% of the total variance in leg extensor power and 48% in isometric knee extensor strength. In addition, power and strength had a nonshared environmental effect in common accounting for four percent of the variance in power and 52% in strength. Remaining variance for leg extensor power was due to trait-specific shared and nonshared environmental effects. CONCLUSION: Observed genetic effect in common for leg extensor power and maximum voluntary isometric knee extensor strength indicated that these two traits are regulated by the same genes. However, also environmental effects have a significant role in explaining the variability in power and strength. 相似文献
68.
Steele JG Sanders AE Slade GD Allen PF Lahti S Nuttall N Spencer AJ 《Community dentistry and oral epidemiology》2004,32(2):107-114
Age and loss of teeth can be expected to have a complex relationship with oral health-related quality of life. This study aimed to explain how age and tooth loss affect the impact of oral health on daily living using the short form, 14-item Oral Health Impact Profile (OHIP-14) on national population samples of dentate adults from the UK (1998 UK Adult Dental Health Survey) and Australia (1999 National Dental Telephone Interview Survey). After correcting for key covariables, increasing age was associated with better mean impact scores in both populations. Those aged 30-49 years in Australia showed the worst (highest) scores. In the UK, those aged under 30 showed the highest scores. In both countries, adults aged 70+ showed much better scores than the rest (P < 0.001). When corrected for age, the independent effect of tooth loss was that the worst scores were found where there were fewer than 17 natural teeth in the UK and fewer than 21 teeth in Australia. People with 25 or more teeth averaged much better scores than all other groups (P < 0.001), although there were differences in pattern between countries. When Australians were analysed by region of birth, the pattern of scores by tooth loss for British/Irish immigrants was strikingly similar to that for the UK sample. First-generation immigrants from elsewhere showed much worse overall scores and a profoundly different pattern to the Australian- and British-born groups. Age, number of teeth and cultural background are important variables influencing oral health-related quality of life. 相似文献
69.
Suhonen R Välimäki M Leino-Kilpi H Katajisto J 《Scandinavian journal of caring sciences》2004,18(1):27-36
BACKGROUND: Although there has been some research to identify the dimensions on which individualized care should be measured, the indicators that constitute individualized care remain unclear. OBJECTIVES: To describe briefly the maintenance of individualized care and to test a hypothetical model of individualized care in a sample of surgical patients. DESIGN AND METHODS: A correlational survey design was used. Data were collected with questionnaires from adult patients (n = 454) discharged from surgical wards in one Finnish hospital district (response rate 91%). Structural equation modelling LISREL SIMPLIS using maximum likelihood estimation was used to estimate and test the parameters of the hypothesized model derived deductively from the previous literature. RESULTS: The goodness-of-fit statistics supported the basic solution of the Individualized Care Model, although two additional paths indicating error covariances between the sub-concepts were identified in the revised model. In this model individualized care is defined in terms of patients' views of nursing activities aimed at supporting individuality in care and in terms of perceptions of individuality in their own care. CONCLUSIONS: The model has been found to capture attributes that characterize individualized care. It can be used as a basis for evaluation in clinical nursing practice from patients' point of view. The study highlights the importance of patients' clinical situation, personal life situation and decisional control as predictors of individualized care. The results also confirm the construct validity of the previously developed Individualized Care Scale. 相似文献
70.
Hagelberg N Jääskeläinen SK Martikainen IK Mansikka H Forssell H Scheinin H Hietala J Pertovaara A 《European journal of pharmacology》2004,500(1-3):187-192
We review evidence indicating that the striatum and striatal dopamine D2 receptors are involved in the regulation of pain in humans. Painful stimulation produces an increase in regional cerebral blood flow in the human striatum. Pain is a common symptom in patients with nigrostriatal dopaminergic hypofunction. Positron emission tomography findings show that a low dopamine D2 receptor availability in the striatum of healthy subjects (indicating either a low density of dopamine D2 receptors or a high synaptic concentration of dopamine) is associated with a high cold pain threshold and a low capacity to recruit central pain inhibition by conditioning stimulation. Patients with chronic orofacial pain have higher dopamine D2 receptor availability than their age-matched controls. We propose that the striatal dopamine D2 receptor may be an important target for the diagnosis and treatment of chronic pain. 相似文献