全文获取类型
收费全文 | 1223篇 |
免费 | 64篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 60篇 |
妇产科学 | 21篇 |
基础医学 | 118篇 |
口腔科学 | 38篇 |
临床医学 | 56篇 |
内科学 | 191篇 |
皮肤病学 | 10篇 |
神经病学 | 145篇 |
特种医学 | 22篇 |
外科学 | 188篇 |
综合类 | 5篇 |
预防医学 | 172篇 |
眼科学 | 10篇 |
药学 | 71篇 |
肿瘤学 | 174篇 |
出版年
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 15篇 |
2020年 | 27篇 |
2019年 | 22篇 |
2018年 | 25篇 |
2017年 | 19篇 |
2016年 | 21篇 |
2015年 | 24篇 |
2014年 | 25篇 |
2013年 | 43篇 |
2012年 | 75篇 |
2011年 | 81篇 |
2010年 | 44篇 |
2009年 | 37篇 |
2008年 | 82篇 |
2007年 | 77篇 |
2006年 | 107篇 |
2005年 | 75篇 |
2004年 | 72篇 |
2003年 | 79篇 |
2002年 | 85篇 |
2001年 | 13篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 11篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1967年 | 2篇 |
1966年 | 3篇 |
1965年 | 2篇 |
1964年 | 2篇 |
排序方式: 共有1290条查询结果,搜索用时 15 毫秒
991.
Lahelma E Laaksonen M Martikainen P Rahkonen O Sarlio-Lähteenkorva S 《Social science & medicine (1982)》2006,63(5):1383-1399
While serious mental disorders typically show socioeconomic differences similar to physical illness-that is, that lower positions imply poorer health-differences for common mental disorders have been inconsistent. We aim to clarify the associations and pathways between measures of socioeconomic circumstances and common mental disorders by simultaneously analysing several past and present socioeconomic measures. The data were derived from middle-aged women and men employed by the City of Helsinki. Cross-sectional surveys were conducted in 2000-2002 among employees who, during each year, reached 40, 45, 50, 55 or 60 years of age. The pooled data include 8970 respondents (80% women; response rate 67%). Common mental disorders were measured by GHQ-12 and the SF-36 mental component summary. Seven socioeconomic measures were included: parental education, childhood economic difficulties, own education, occupational class, household income, home ownership, and current economic difficulties. Logistic regression analysis was used to examine associations between the socioeconomic circumstances and common mental disorders. Past and present economic difficulties were strongly associated with common mental disorders, whereas conventional past and present socioeconomic status measures showed weak or slightly reverse associations. Adjusting for age and gradually for each socioeconomic measure did not affect the main findings, which were very similar for women and men, as well as for both measures of common mental disorders. While the associations of conventional socioeconomic status measures with common mental disorders were weak and inconsistent, our results highlight the importance of past and present economic difficulties to these disorders. 相似文献
992.
PURPOSE: To estimate the repeatability of refractive error measurement (REM) in a clinical environment in cataractous, pseudophakic and healthy eyes. METHODS: The refractive error of patients referred for cataract surgery or consultation measured by ophthalmic professionals was re-examined and the measurement results were compared. A total of 99 eyes from 99 persons (41 cataractous, 36 pseudophakic and 22 healthy eyes) with visual acuity (VA) of 0.3-1.3 (logMAR 0.52 to - 0.11) were included. The differences between measurements 1 and 2 were calculated as 3-dimensional vector values and spherical equivalents (SEs) and expressed as the coefficient of repeatability (CR). The mean time interval between the first and second examinations was 45 days. RESULTS: The CRs for all eyes for vertical (V), torsional (T) and horizontal (H) vectors were 0.74 D, 0.34 D and 0.93 D, respectively. The CR of SE for all eyes was 0.74 D. Eyes with lower VA (0.3-0.45) had larger variability in vector and SE values but the differences between VA groups were not statistically significant. The difference in the mean defocus equivalent (DE) between measurements 1 and 2 was, however, significantly greater in the group with lower VA. In all VA groups the mean difference vector was very close to the zero vector, which means that there was no systematic difference. CONCLUSIONS: Repeatability of refractive error measurements in clinical settings has a certain degree of variability. In this series, the variability in eyes with better VA was not great and was in accordance with earlier findings in healthy eyes. Eyes with lower VA had greater variability due to greater tolerance to defocus. Thus, conclusions concerning changes in the refractive state and the need to make changes in the refractive correction of eyes with poorer vision should be made with caution. 相似文献
993.
We describe an information-theoretic framework for fitting neural spike responses with a Linear-Nonlinear-Poisson cascade model. This framework unifies the spike-triggered average (STA) and spike-triggered covariance (STC) approaches to neural characterization and recovers a set of linear filters that maximize mean and variance-dependent information between stimuli and spike responses. The resulting approach has several useful properties, namely, (1) it recovers a set of linear filters sorted according to their informativeness about the neural response; (2) it is both computationally efficient and robust, allowing recovery of multiple linear filters from a data set of relatively modest size; (3) it provides an explicit "default" model of the nonlinear stage mapping the filter responses to spike rate, in the form of a ratio of Gaussians; (4) it is equivalent to maximum likelihood estimation of this default model but also converges to the correct filter estimates whenever the conditions for the consistency of STA or STC analysis are met; and (5) it can be augmented with additional constraints on the filters, such as space-time separability. We demonstrate the effectiveness of the method by applying it to simulated responses of a Hodgkin-Huxley neuron and the recorded extracellular responses of macaque retinal ganglion cells and V1 cells. 相似文献
994.
Holl RW Swift PG Mortensen HB Lynggaard H Hougaard P Aanstoot HJ Chiarelli F Daneman D Danne T Dorchy H Garandeau P Greene S Hoey HM Kaprio EA Kocova M Martul P Matsuura N Robertson KJ Schoenle EJ Sovik O Tsou RM Vanelli M Aman J 《European journal of pediatrics》2003,162(1):22-29
The optimal insulin regimen for paediatric patients with type 1 diabetes remains controversial. Therefore this multicentre study was performed in adolescents over a 3-year period to assess metabolic control, severe hypoglycaemia, and weight gain in relation to insulin injection regimens. Out of 2873 children and adolescents in an international survey in 1995, 872 adolescents (433 boys, 439 girls, mean age in 1995 11.3+/-2.2 years) were restudied in 1998, relating insulin regimens to HbA(1c) measured in a central laboratory. In addition, the daily dose of insulin, changes in body mass index (BMI), and events of severe hypoglycaemia were evaluated. Over 3 years, the use of multiple injection regimens increased from 42% to 71%: 251 patients remained on twice daily insulin, 365 remained on multiple injections and 256 shifted from twice daily insulin to multiple injections. In all three subgroups an increase in insulin dose, a deterioration of metabolic control, and an increase in BMI were observed. Metabolic control deteriorated less than expected over 3 years during adolescence (HbA(1c) 1995: 8.7+/-1.6%; 1998 observed: 8.9+/-1.6%, HbA(1c) expected for 1998: 9.0%). BMI increased more than expected, the increase was greatest in patients switching from twice daily to multiple injections, and higher in females compared to males. CONCLUSION: in this international study, metabolic control was unsatisfactory in many adolescents with type 1 diabetes irrespective of the insulin regimen. No improvement in metabolic control was observed in this cross-sectional survey, over 3 years in any of the subgroups. Even the group switching from twice to multiple injections did not improve blood glucose control and the increase in body mass index was most pronounced in this group. Conclusive evidence, however, should be based on prospectively planned, randomised therapeutic trials in paediatric patients. 相似文献
995.
Radial palsy in shaft fracture of the humerus 总被引:2,自引:0,他引:2
Ole B stman Georg Bakalim Seppo Vainionp Eero Wiippula Hannu P ti l Pentti Rokkanen 《Acta orthopaedica》1986,57(4):316-319
Fifty-nine patients with immediate and 16 with secondary radial nerve palsy complicating a fracture of the shaft of the humerus were reviewed. According to the preferences of the surgeon in charge, the palsy was treated either with early exploration of the radial nerve and internal fixation of the fracture or with initial expectance. Of the latter, 12 were later explored.
No useful recovery of motor function could be seen in 13/59 patients with immediate and in 2/16 patients with secondary palsy. In patients with immediate palsy treated by early exploration, there were 8/27 nonrecoveries. Among those treated with initial expectance, there were 5/32 nonrecoveries. For secondary palsy, these figures were 2/10 and 0/6, respectively.
No support emerged for routine early exploration. 相似文献
No useful recovery of motor function could be seen in 13/59 patients with immediate and in 2/16 patients with secondary palsy. In patients with immediate palsy treated by early exploration, there were 8/27 nonrecoveries. Among those treated with initial expectance, there were 5/32 nonrecoveries. For secondary palsy, these figures were 2/10 and 0/6, respectively.
No support emerged for routine early exploration. 相似文献
996.
Eero Kerosuo Heidi Kerosuo Pekka Kallio Ursuline Nyandini 《Community dentistry and oral epidemiology》1986,14(6):338-340
In the developing countries, the main dental problem has traditionally been periodontal disease, but recently dental caries has been reported to be increasing. There are some findings showing the same pattern in Tanzania. The aim of the present study was to explore the prevalence of caries and the periodontal status among schoolchildren in Dar es Salaam. The series consisted of pupils of classes 6 and 7 in five primary schools (n = 640, ages 12-18 yr). Two-thirds of the children examined were caries-free. Boys had significantly lower DMF scores than girls, 0.7 and 1.2, respectively. Almost all the children showed early signs of gingivitis and assessment by the Community Periodontal Index of Treatment Needs (CPITN) showed that in over 50% all sextants of the mouth were affected. In the older age group (15-18 yr) girls had a significantly higher number of periodontally healthy sextants than boys. The results confirm the high prevalence of periodontal problems but show a very low prevalence of caries. Thus, there are no signs of an alarming caries problem in Dar es Salaam, but oral hygiene education should be promoted. 相似文献
997.
Differential involvement of CCK-A and CCK-B receptors in the regulation of locomotor activity in the mouse 总被引:1,自引:0,他引:1
The influence of the CCK-A antagonist devazepide and the CCK-B/gastrin antagonist L-365,260 on the locomotor activity of mice was studied. Devazepide and L-365,260 had opposite effects on spontaneous locomotor activity, and on caerulein- and apomorphine-induced hypomotility in the mouse. Devazepide in high doses (0.1-1 mg/kg IP) reduced spontaneous motor activity, whereas L-365,260 at a high dose (1 mg/kg IP) increased the activity of mice. Devazepide (0.1-10 micrograms/kg) moderately antagonized the sedative effect of apomorphine (0.1 mg/kg SC) and caerulein (25 micrograms/kg SC), whereas L-365,260 (1-10 micrograms/kg) significantly potentiated the actions of dopamine and CCK agonists. Concomitant administration of caerulein (15 micrograms/kg SC) and apomorphine (0.1 mg/kg SC) caused an almost complete loss of locomotor activity in the mouse. Devazepide and L-365,260 (0.1-10 micrograms/kg) were completely ineffective against caerulein-induced potentiation of apomorphine hypomotility. Devazepide in high doses (0.1-1 mg/kg), reducing the spontaneous motor activity of mice, counteracted the motor excitation induced by d-amphetamine (5 mg/kg IP). The CCK agonist caerulein (100 micrograms/kg SC) had a similar antiamphetamine effect. Devazepide (1-100 micrograms/kg) and L-365,260 (1 micrograms/kg) reversed completely the antiamphetamine effect of caerulein. The results of present study reflect apparently distinct role of CCK-A and CCK-B receptors in the regulation of motor activity. The opposite effect of devazepide and L-365,260 on caerulein- and apomorphine-induced hypolocomotion is probably related to the antagonistic role of CCK-A and CCK-B receptor subtypes in the regulation of mesencephalic dopaminergic neurons. The antiamphetamine effect of caerulein is possibly linked to the stimulation of CCK-A receptors in the mouse brain, whereas the blockade of both subtypes of the CCK-8 receptor is involved in the antiamphetamine effect of devazepide. 相似文献
998.
The CT findings of 29 patients with recurrent lumbar disc herniation, confirmed at reoperation, were analyzed. The shape of the recurrent herniation varied from a shallow bulge to round or triangular mass. Every lesion presented density numbers compatible with disc material. An enhancement study was made in six cases, and the lesions remained non-enhanced. Density measurement on CT proved reliable in the differential diagnosis between recurrent disc herniation and postoperative scar. 相似文献
999.
1000.
Effects of rapid eye movement (REM) sleep deprivation on meal size and feeding speed were investigated by means of the cuff pedestal technique in 9 male rats exposed to partial food restriction. Reduction of available food by 50% alone, when accomplished by providing the pellets at the beginning of each dark period, during 7 consecutive days, induced a quite linear increase both in the meal size and feeding speed. When the same feeding schedule was repeated in combination with REM sleep deprivation, the meal size remained smaller and the feeding time was prolonged (during the first 3–4 days) when compared to those during food restriction alone, although losses of body weight were almost doubled. These findings are in agreement with the effects of REM sleep deprivation on the meal pattern in rats on ad libitum diet and provide further support for the suggestion of the importance of REM sleep in the generation of the light/dark rhythm of feeding in the rat. 相似文献