全文获取类型
收费全文 | 4155篇 |
免费 | 297篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 109篇 |
妇产科学 | 73篇 |
基础医学 | 582篇 |
口腔科学 | 441篇 |
临床医学 | 323篇 |
内科学 | 888篇 |
皮肤病学 | 150篇 |
神经病学 | 285篇 |
特种医学 | 194篇 |
外科学 | 431篇 |
综合类 | 35篇 |
预防医学 | 400篇 |
眼科学 | 34篇 |
药学 | 312篇 |
中国医学 | 39篇 |
肿瘤学 | 136篇 |
出版年
2023年 | 39篇 |
2022年 | 87篇 |
2021年 | 163篇 |
2020年 | 107篇 |
2019年 | 140篇 |
2018年 | 170篇 |
2017年 | 98篇 |
2016年 | 135篇 |
2015年 | 131篇 |
2014年 | 199篇 |
2013年 | 201篇 |
2012年 | 359篇 |
2011年 | 331篇 |
2010年 | 188篇 |
2009年 | 147篇 |
2008年 | 225篇 |
2007年 | 240篇 |
2006年 | 177篇 |
2005年 | 167篇 |
2004年 | 141篇 |
2003年 | 152篇 |
2002年 | 130篇 |
2001年 | 66篇 |
2000年 | 87篇 |
1999年 | 59篇 |
1998年 | 34篇 |
1997年 | 33篇 |
1996年 | 35篇 |
1995年 | 16篇 |
1994年 | 21篇 |
1993年 | 23篇 |
1992年 | 32篇 |
1991年 | 30篇 |
1990年 | 22篇 |
1989年 | 21篇 |
1988年 | 31篇 |
1987年 | 30篇 |
1986年 | 25篇 |
1985年 | 22篇 |
1984年 | 23篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1971年 | 9篇 |
1966年 | 6篇 |
排序方式: 共有4464条查询结果,搜索用时 15 毫秒
41.
M N Sato E H Yamashiro-Kanashiro M M Tanji R Kaneno R Y Iqueoka A J Duarte 《Revista do Instituto de Medicina Tropical de S?o Paulo》1991,33(3):187-192
The immunomodulatory effect of cimetidine (CIM), a histamine type-2 receptor antagonist, was evaluated in respect to the blastogenic response to Con A of Wistar Furth (WF) rats infected by the Y strain of Trypanosoma cruzi (T. cruzi). Enhancement of blastogenesis of normal splenocytes was observed at a concentration of 10(3) M. However, the splenocytes from infected animals responded to concentrations of CIM ranging from 10(-8) to 10(-3) M. The mitogenic response to Con A of cells from infected animals was restored in the presence of CIM. The results show that CIM modulates the "in vitro" proliferative response of cells from T. cruzi-infected rats and suggest an immunoregulatory role of histamine and/or of cells that express H2 receptors in this infection. 相似文献
42.
Costa MF Novis SA Niemeyer Filho P Pimentel ML Novis RF Duarte F 《Arquivos de neuro-psiquiatria》2000,58(4):1133-1137
We report the association a multiple sclerosis (MS), spinal cord tumour and intracranial tumor in a 63 years-old female patient with a 10 years history of relapsing/remitting MS. Symptoms usually remitted in response to costicosteroid therapy. In 1997 the patient presented with paraparesis and paresis of right arm which did not respond to corticotherapy. A spinal RMI revealed in the cervical spinal an intra spinal cord tumour, further diagnosed as ependymoma, and a parietal region meningioma. We call attention to this rare association of central nervous system tumour and MS, enphasizing the need for investigation of new and uncommon symptoms during the evolution of MS. 相似文献
43.
Aguirre Benites JF Duarte Ojeda JM Díaz González R Leiva Galvis O 《Actas urologicas espa?olas》2000,24(1):65-67
Introduction of a new approach for uretero-ileal implantation when only one kidney is available. The technique follows the same approach as the Wallace-type re-implantation but in this case the uretero-ileal anastomosis plate is formed with the far en 2-3 cm of ureter. All cases performed with this technique have been highly successfull as reported in this clinical account. 相似文献
44.
Restoration of impaired T-cell proliferation after parathyroidectomy in hemodialysis patients 总被引:3,自引:0,他引:3
BACKGROUND/AIMS: Severe secondary hyperparathyroidism is not infrequent in hemodialysis patients and recent studies suggest that parathyroid hormone (PTH) may play a role in the genesis of cell immunity abnormalities in uremia. The aim of the present study is to describe the effect of parathyroidectomy on T- and B-cell functions in hemodialysis patients. METHODS: The study was performed on 6 patients with severe secondary hyperparathyroidism. iPTH, B, CD4(+), CD8(+), total number of lymphocytes, lymphoproliferative response to PHA, PWM and Candidin, and IgG, IgM, IL-2 production in vitro were determined 1 day before and 4 months after parathyroidectomy. RESULTS: The lymphoproliferative response to PHA increased significantly after parathyroidectomy. We also observed a trend to an increase in production of IgG and IgM after PWM stimulation before therapy. CONCLUSION: The present study suggests that patients with extremely high levels of PTH show a complete restoration of impaired T-cell proliferation after parathyroidectomy. 相似文献
45.
46.
Elisabeth Meloni Vieira Alcyone Artioli Machado Geraldo Duarte Regina Helena Brito de Souza Antonio Luis Rodrigues Junior 《Pan American journal of public health》2004,15(6):373-379
OBJECTIVES: To study HIV-positive women and women at risk of becoming infected with HIV who attended HIV prevention education group sessions at a university hospital in Brazil and to compare the use of the female condom and the male condom by these two groups of women. METHODS: The study subjects were 165 women participating in HIV prevention education group sessions at the Medical School Hospital of Ribeir?o Preto of the University of S?o Paulo, in the city of Ribeir?o Preto, S?o Paulo, Brazil. Women could be enrolled in the study from August 2000 to June 2001, and the follow-up observation time period was from August 2000 to July 2001. Male condoms and female condoms were freely distributed to all the participants at the end of each educational session and also at the end of each follow-up visit that the participants made. Each woman took part in an initial interview and was asked to return monthly. At each follow-up visit an additional short interview was carried out in order to investigate use of the male condom and of the female condom. Variables that were examined for the study included age, education, ethnic group, marital or relationship status, number of children, the women's use of male condoms and female condoms, commercial sex (whether the women had ever had sex in exchange for money, gifts, or favors), and previous knowledge of the female condom. RESULTS: The 165 women studied fell into the following three categories: 132 of them (80.0%) were HIV-positive, 26 of them (15.8%) had a sexually transmitted disease (STD) other than HIV and did not have an HIV-positive partner, and 7 of them (4.2%) had an HIV-positive partner but did not have HIV or any other STD. The women ranged in age from 15 to 64 years, with a mean of 30.3 years. Of the women in the study, 69.7% of them were married or were cohabitating, and 90.9% of them had a sexual partner. Just over two-thirds of the women had seven years of formal schooling or less. Out of 163 women, a total of 31 of them (19.0%) had never used the male condom with a partner, and 49 of the 163 (30.1%) had not used a male condom at the time of the last sexual intercourse. Out of the 165 women, 74 of them (44.8%) returned for at least one follow-up visit. Of these 74 women, 58 of them (78.3%) reported using the female condom between the initial interview and the first follow-up visit. The majority of the 74 women who returned for a visit liked using the female condom, and the women reported that their partners also generally accepted the female condom. In comparison to women at risk of HIV, HIV-positive women were more likely to have used the male condom with a partner before the initial interview. Women who continued returning over a longer follow-up period were more likely to have used the female condom at the time of the last sexual intercourse. No association was found between female condom use at the time of last sexual intercourse and the woman's HIV infection status. CONCLUSIONS: In comparison to the women at risk of HIV, the HIV-positive women in our study were more likely to use male condoms with their partners, to return for follow-up visits, and to have a longer follow-up period. The acceptance of the female condom among the HIV-positive women in this study, as reported at their first follow-up visit, appears to be similar to the acceptance of the female condom among women in general in Brazil. 相似文献
47.
Adult rats submitted to maternal deprivation (DEP) on post-natal day (pnd) 11 show smaller corticosterone (CORT) response to a saline injection than non-deprived (NDEP) rats, mainly at 30 days of age. In the present study we sought to investigate the pituitary-adrenal axis response of 30-day-old DEP rats to a 5-min open-field session, with lights and sound on. Hormone levels were assessed immediately or 20 min after the end of the stress, and were compared to basal levels. The immediate ACTH response of DEP females was the highest; this difference was no longer observed at 20 min, but hormone levels were still higher than basal. Both males and females showed an augmented CORT secretion immediately after the open field session, although only the response of NDEP females was higher than that of male counterparts. Moreover, DEP females showed a lower CORT response than their NDEP counterparts immediately after the stress. The CORT stress response remained equally elevated in males and females at the 20-min time point. Finally, DEP animals, regardless of the gender, ambulated more in the centre of the open field and displayed less grooming behaviour than NDEP pups, suggesting that DEP rats are less emotional than NDEP animals. 相似文献
48.
49.
Virgília S Silva Ana I Duarte A Cristina Rego Catarina R Oliveira Paula P Gon?alves 《Toxicological sciences》2005,88(2):485-494
The ability of aluminum to inhibit the (Na(+)/K(+))ATPase activity has been observed by several investigators. The (Na(+)/K(+))ATPase is characterized by a complex molecular heterogeneity that results from the expression and differential association of multiple isoforms of both catalytic (alpha) and regulatory (beta) subunits. For instance, three main alpha (alpha(1), alpha(2) and alpha(3)) and three beta (beta(1), beta(2) and beta(3)) subunit isoforms exist in vertebrate nervous tissue, whereas only alpha(1) and beta(1) have been identified in kidney. However, no studies have focused on determining the change in (Na(+)/K(+))ATPase isoforms caused by chronic exposure to aluminum and its relation with aluminum toxicity. In this study, adult male Wistar rats were submitted to chronic dietary AlCl(3) exposure (0.03 g/day of AlCl(3) for 4 months), and the activity and protein expression of (Na(+)/K(+))ATPase isozymes were studied in brain cortex synaptosomes and in kidney homogenates. The intracellular levels of adenine nucleotides, plasma membrane integrity, and aluminum accumulation were also studied in brain synaptosomes. Aluminum accumulation upon chronic dietary AlCl(3) administration significantly decreased the (Na(+)/K(+))ATPase activity measured in the presence of nonlimiting Mg-ATP concentrations, without compromising protein expression of alpha-subunit isoforms in brain and kidney. Aluminum-induced synaptosomal (Na(+)/K(+))ATPase inhibition was due to a reduction in the activity of isozymes containing alpha(1)-alpha(2) and alpha(3)-subunits. The onset of enzyme inhibition was accompanied by a decrease of the (Na(+)/K(+))ATPase sensitivity to submicromolar concentrations of ouabain, and it preceded major damage in plasma membrane integrity and energy supply, as revealed by the analysis of lactate dehydrogenase leakage and endogenous adenine nucleotides. The data suggest that, during chronic dietary exposure to AlCl(3), brain (Na(+)/K(+))ATPase activity drops, even if no significant alterations of catalytic subunit protein expression, cellular energy depletion, and changes in cell membrane integrity are observed. Implications regarding underlying mechanisms of aluminum neurotoxicity are discussed. 相似文献
50.
目的:建立以高效液相色谱法测定小儿磨积片中橙皮苷含量的方法。方法:色谱柱为SpherisorbC18,流动相为甲醇-冰醋酸-水(25∶4∶71),检测波长为283nm,流速为2·0ml/min,柱温为50℃,灵敏度为0·16AUFS,进样量为20μl。结果:橙皮苷进样量在0·024μg~1·2μg范围内与峰面积积分值呈良好的线性关系(r=0·9999),平均回收率为99·1%(RSD=0·8%)。结论:本方法简便、快捷,灵敏度及准确度高,可为小儿磨积片质量控制提供依据。 相似文献