全文获取类型
收费全文 | 2174篇 |
免费 | 99篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 82篇 |
妇产科学 | 45篇 |
基础医学 | 342篇 |
口腔科学 | 53篇 |
临床医学 | 161篇 |
内科学 | 457篇 |
皮肤病学 | 41篇 |
神经病学 | 250篇 |
特种医学 | 41篇 |
外科学 | 211篇 |
综合类 | 11篇 |
一般理论 | 2篇 |
预防医学 | 262篇 |
眼科学 | 18篇 |
药学 | 195篇 |
中国医学 | 7篇 |
肿瘤学 | 90篇 |
出版年
2024年 | 3篇 |
2023年 | 23篇 |
2022年 | 56篇 |
2021年 | 102篇 |
2020年 | 50篇 |
2019年 | 77篇 |
2018年 | 98篇 |
2017年 | 48篇 |
2016年 | 63篇 |
2015年 | 59篇 |
2014年 | 91篇 |
2013年 | 126篇 |
2012年 | 156篇 |
2011年 | 197篇 |
2010年 | 90篇 |
2009年 | 88篇 |
2008年 | 120篇 |
2007年 | 135篇 |
2006年 | 99篇 |
2005年 | 112篇 |
2004年 | 102篇 |
2003年 | 89篇 |
2002年 | 67篇 |
2001年 | 18篇 |
2000年 | 18篇 |
1999年 | 20篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 17篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 8篇 |
1971年 | 2篇 |
1966年 | 3篇 |
1962年 | 2篇 |
排序方式: 共有2278条查询结果,搜索用时 15 毫秒
1.
2.
Irene B. Jensen Catarina Dahlquist Åke Nygren Eva Royen Monica Stenberg 《Journal of occupational rehabilitation》1997,7(4):225-238
This prospective randomized controlled outcome study was designed to evaluate whether a MultiModal Cognitive—Behavioral Treatment for chronic spinal pain (MMCBT) specifically designed for women has an increased effect on well being and return to work compared to a regular MMCBT regimen. In Sweden, spinal pain is most prevalent among women. A tremendous amount of money is spent on secondary prevention of spinal pain. Yet, little is known about the effect of the interventions. A need for well designed outcome studies exist. Fifty-four subjects from a cohort of all registered sick-listed women in three districts of Stockholm participated in the study. Subjects were allocated by central randomization into two groups. One group was treated with a regular MMCBT program and the other group with a MMCBT program specifically designed for women. Assessments were performed at pretreatment–posttreatment (last treatment day) and at 6 and 18 months posttreatment. Questionnaires covering the bio-psycho-social spectra of the chronic pain syndrome, and sick leave were used to measure outcome. Intention to treat and true to protocol analyses were performed. The only significant differences found between groups were improvements in self-reported disability and in coping with pain, favoring the experimental treatment. About one-third of the variance in disability was explained by the set of pain-coping strategies assessed in the study. The results do not lend sufficient statistical support to warrant acceptance of the experimental treatment as superior to the regular treatment in improving health and sick leave. Further investigation with larger groups is needed before a solid scientific conclusion can be drawn. 相似文献
3.
N M Delgado R Reyes A Carranco L Huacuja H Merchant A Rosado 《Archives of andrology》1990,25(2):121-129
The effect of specific glycosaminoglycan-hydrolyzing enzymes on the ruthenium red staining of pig spermatozoa was studied. Washed spermatozoa were incubated at 35 degrees C in buffer or with neuraminidase 0.5 units/ml, heparinase 0.2 mg/ml, or chondroitinase ABC 2.0 units/ml. After incubation sperm cells were washed, stained with ruthenium red and studied under the electron microscope. Anionic sites in the surface of untreated spermatozoa follow regularly the plasma membrane, but present are numerous processes constituting what has been defined as the glycocalyx. Neuraminidase did not affect the distribution of ruthenium red on the surface of the spermatozoa, but eliminated almost completely the processes of the glycocalyx. Heparinase caused loss of the ruthenium red-stained sites on the membrane surface of pig spermatozoa with less influence on the dense processes of the glycocalyx. A similar loss of ruthenium red-stained sites was observed with nitrous acid treatment. A striking effect of treatment with chondroitinase ABC was the production of a typical acrosome reaction. 相似文献
4.
5.
Shelley E Taylor Barbara J Lehman Catarina I Kiefe Teresa E Seeman 《Neuropsychopharmacology》2006,60(8):819-824
BACKGROUND: Low socioeconomic status (SES) and a harsh family environment in childhood have been linked to mental and physical health disorders in adulthood. The objective of the present investigation was to evaluate a developmental model of pathways that may help explain these links and to relate them to C-reactive protein (CRP) in the Coronary Artery Risk Development in Young Adults (CARDIA) dataset. METHODS: Participants (n = 3248) in the CARDIA study, age 32 to 47 years, completed measures of childhood SES (CSES), early family environment (risky families [RF]), adult psychosocial functioning (PsyF, a latent factor measured by depression, mastery, and positive and negative social contacts), body mass index (BMI), and C-reactive protein. RESULTS: Structural equation modeling indicated that CSES and RF are associated with C-reactive protein via their association with PsyF (standardized path coefficients: CSES to RF, RF to PsyF, PsyF to CRP, CSES to CRP, all p < .05), with good overall model fit. The association between PsyF and CRP was partially mediated by BMI (PsyF to BMI, BMI to CRP, both p < .05). CONCLUSIONS: Low childhood SES and a harsh early family environment appear to be related to elevated C-reactive protein in adulthood through pathways involving psychosocial dysfunction and high body mass index. 相似文献
6.
Catarina Gonzalez da Silva Karl Magnus Petersson Luís Faísca Martin Ingvar Alexandra Reis 《Journal of clinical and experimental neuropsychology》2004,26(2):266-277
Semantic verbal fluency tasks are commonly used in neuropsychological assessment. Investigations of the influence of level of literacy have not yielded consistent results in the literature. This prompted us to investigate the ecological relevance of task specifics, in particular, the choice of semantic criteria used. Two groups of literate and illiterate subjects were compared on two verbal fluency tasks using different semantic criteria. The performance on a food criterion (supermarket fluency task), considered more ecologically relevant for the two literacy groups, and an animal criterion (animal fluency task) were compared. The data were analysed using both quantitative and qualitative measures. The quantitative analysis indicated that the two literacy groups performed equally well on the supermarket fluency task. In contrast, results differed significantly during the animal fluency task. The qualitative analyses indicated differences between groups related to the strategies used, especially with respect to the animal fluency task. The overall results suggest that there is not a substantial difference between literate and illiterate subjects related to the fundamental workings of semantic memory. However, there is indication that the content of semantic memory reflects differences in shared cultural background--in other words, formal education--, as indicated by the significant interaction between level of literacy and semantic criterion. 相似文献
7.
J E Gervasoni R N Taub M T Yu D Warburton M Sabbath S Gilleran D L Coppock J D'Alessandri S Krishna M Rosado 《Cancer research》1992,52(19):5244-5249
Anthracycline-resistant HL-60/AR cells and their drug-sensitive HL-60/S counterparts were characterized by karyotypic analysis and examined for the overexpression of DNA and mRNA sequences coding for P-glycoprotein (Pgp). The HL-60/S cells were karyotypically stable over a 5-year period of study (1986-1991), except for an additional small Giemsa-positive band noted at 7q22 in cultures harvested in 1987, but not in 1986. This change did not affect drug sensitivity. The drug-resistant HL-60/AR cells examined in 1986, 1987, and 1991 demonstrated a very stable karyotype. The most striking feature was a large homogeneously staining region in the long arm of chromosome 7 (7q11.2), and translocation of the remainder of the long arm to another centromere. Other changes in the HL-60/AR cells included inversion in 9q, partial deletion of the short arm of chromosome 10p, addition of material to the p arm of der(16), loss of chromosome 22, and the appearance of a new marker chromosome. Both HL-60/S and the HL-60/AR cells were found not to amplify DNA or mRNA sequences coding for the Pgp. Thus, although the HL-60/AR cells possess the classical multidrug resistance phenotype and demonstrate a homogeneously staining region near the region of the MDR1 gene, their resistance is due to mechanisms other than those coded for by MDR1. 相似文献
8.
Raquel Carreira Ana Duarte Pedro Monteiro Maria Sancha Santos Ana Cristina Rego Catarina R Oliveira Lino M Gon?alves Luís A Providência 《Revista portuguesa de cardiologia》2004,23(11):1447-1455
Ischemia negatively affects mitochondrial function by inducing the mitochondrial permeability transition (MPT). The MPT is triggered by oxidative stress, which occurs in mitochondria during ischemia as a result of diminished antioxidant defenses and increased reactive oxygen species production. It causes mitochondrial dysfunction and can ultimately lead to cell death. Therefore, drugs able to minimize mitochondrial damage induced by ischemia may prove to be clinically effective. We analyzed the effect of carvedilol, a beta-blocker with antioxidant properties, on mitochondrial dysfunction. Carvedilol decreased levels of TBARS (thiobarbituric acid reactive substances), an indicator of oxidative stress, which is consistent with its antioxidant properties. Regarding cell death by apoptosis, although ischemia did increase caspase-8-like activity, there were no changes in caspase-3-like activity, which is activated downstream of caspase-8; this may indicate that the apoptotic cascade is not activated by 60 minutes of ischemia. We conclude that carvedilol protects ischemic mitochondria by preventing oxidative mitochondrial damage, and, by so doing, it may also inhibit the formation of the MPT pore. 相似文献
9.
Catarina Eira Jordi Miquel José Vingada Jordi Torres 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2006,51(2):119-122
Gongylonema neoplasticum was identified in the oesophagus of 14 wild rabbits (Oryctolagus cuniculus) from Portugal. This is the first record of Gongylonema neoplasticum in a naturally infected lagomorph species in Europe. This paper presents the most relevant measurements of adult worms and
some of their surface features seen by scanning electron microscopy. Epidemiological aspects of G. neoplasticum such as geographical distribution, host spectrum and biological features are discussed. 相似文献
10.
R Esturau P Iturralde S Férez O Galván J Rosado G Pérez J A González Hermosillo 《Archivos del Instituto de Cardiología de México》1991,61(3):205-210
From June 1988 to June 1990 we studied fifty patients who had implantation of a pacemaker. (31 females and 19 males). All of them underwent stress test with Bruce's protocol. Patients were divided in two groups; pacemaker-independent (PI) and pacemaker-dependent (PD). Over 50% of the patients inhibited the pacemaker with their own rhythm, most of them had sinus dysfunction. Complete A-V block was predominant in PD. The group of PI achieved more mets and had more oxygen consumption. Blood pressure response was similar in both groups. 相似文献