全文获取类型
收费全文 | 837篇 |
免费 | 49篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 31篇 |
妇产科学 | 7篇 |
基础医学 | 116篇 |
口腔科学 | 20篇 |
临床医学 | 87篇 |
内科学 | 241篇 |
皮肤病学 | 8篇 |
神经病学 | 21篇 |
特种医学 | 166篇 |
外科学 | 39篇 |
综合类 | 26篇 |
预防医学 | 71篇 |
眼科学 | 7篇 |
药学 | 59篇 |
肿瘤学 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 14篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 17篇 |
2014年 | 21篇 |
2013年 | 27篇 |
2012年 | 33篇 |
2011年 | 23篇 |
2010年 | 28篇 |
2009年 | 37篇 |
2008年 | 22篇 |
2007年 | 36篇 |
2006年 | 14篇 |
2005年 | 15篇 |
2004年 | 29篇 |
2003年 | 25篇 |
2002年 | 21篇 |
2001年 | 18篇 |
2000年 | 13篇 |
1999年 | 19篇 |
1998年 | 53篇 |
1997年 | 45篇 |
1996年 | 40篇 |
1995年 | 30篇 |
1994年 | 23篇 |
1993年 | 33篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 27篇 |
1988年 | 21篇 |
1987年 | 26篇 |
1986年 | 13篇 |
1985年 | 20篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 2篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有925条查询结果,搜索用时 0 毫秒
51.
King CH Blanton RE Muchiri EM Ouma JH Kariuki HC Mungai P Magak P Kadzo H Ireri E Koech DK 《The American journal of tropical medicine and hygiene》2004,70(1):57-62
To estimate their heritable component of risk for Schistosoma haematobium infection intensity and disease, we performed a community-based family study among an endemic population in coastal Kenya. Demography and family linkages were defined by house-to-house interviews, and infection prevalence and disease severity were assessed by standard parasitologic testing and by ultrasound. The total population was 4,408 among 912 households, with 241 identified pedigree-household groups. Although age- and sex-adjusted risk for greater infection intensity was clustered within households (odds ratio = 2.7), analysis of extended pedigree-household groups indicated a relatively low heritability score for this trait (h2 = 0.199), particularly after adjustment for common household exposure effects (adjusted h2 = 0.086). Statistical evidence was slightly stronger (h2 = 0.353) for familial clustering of bladder morbidity, with an adjusted h2 = 0.142 after accounting for household exposure factors. We conclude that among long-established populations of coastal Kenya, heritable variation in host susceptibility is low, and likely plays a minimal role in determining individual risk for infection or disease. 相似文献
52.
Naus CW Jones FM Satti MZ Joseph S Riley EM Kimani G Mwatha JK Kariuki CH Ouma JH Kabatereine NB Vennervald BJ Dunne DW 《The Journal of infectious diseases》2003,187(8):1272-1282
We examined specific immunoglobulin G1 (IgG1) and IgG3 responses to Plasmodium falciparum schizont and Schistosoma mansoni egg and worm antigens in individuals from Kenya, Uganda, and the Sudan who had been exposed to malaria and schistosomiasis. A strong correlation between malaria- and schistosome-specific IgG3 responses was observed. This association appears to result from the presence of cross-reactive components of the 2 parasites that bind IgG3 antibodies, rather than to be mediated by immunological cross-regulation or specific regulatory mechanisms induced by either parasite. Cross-reactivity of IgG3 antibodies was confirmed in a Brazilian cohort of individuals living in an area where schistosomiasis is endemic but no malaria occurs and in a Pakistani cohort from an area where malaria is endemic but no schistosomiasis occurs. An IgG3 interaction with antigens from both parasites was observed in individuals from both cohorts, but not in uninfected European control subjects. The immunological and biological implications of this observation require further exploration. 相似文献
53.
54.
Mkoji GM Hofkin BV Kuris AM Stewart-Oaten A Mungai BN Kihara JH Mungai F Yundu J Mbui J Rashid JR Kariuki CH Ouma JH Koech DK Loker ES 《The American journal of tropical medicine and hygiene》1999,61(5):751-759
The Louisiana red swamp crayfish, Procambarus clarkii, which was introduced into east Africa in the 1950s or 1960s, has since widely dispersed. Previous work by our group has shown that P. clarkii can reduce populations of the molluscan intermediate hosts of human schistosomes through predatory and competitive interactions. Here, we investigate whether crayfish can reduce populations of Bulinus africanus and consequently, Schistosoma haematobium prevalence in school children. Children from 6 primary schools in the Machakos and Kitui Districts of Kenya were selected for study. Schools were divided into 3 experimental-control pairs. At experimental schools, crayfish were introduced into nearby aquatic habitats harboring Bulinus africanus snails and serving as S. haematobium transmission sites. Snail habitats near control schools did not receive crayfish. Six months after crayfish introduction, all infected children were treated with praziquantel. Children were then monitored quarterly for 2 years, at which time infection and reinfection rates were compared statistically between the paired schools. In one such pair, crayfish failed to establish, resulting in neither snail control nor a reduction in transmission. At the second pair of schools, the numbers of snails were decreased by the presence of crayfish, but a clear difference in infection rates in children could not be detected, primarily because drought conditions kept overall transmission rates low. At the third school pair, crayfish established well in experimental habitats, snail numbers decreased precipitously, and children at the experimental school were significantly less likely to acquire S. haematobium infections than children at the control school. Our results indicate that under certain environmental circumstances, P. clarkii exerts a significant impact on the transmission of human schistosomiasis in Kenya. Important questions remain regarding the impact of P. clarkii on Kenyan freshwater ecosystems, not the least of which is its potential to significantly influence the epidemiology of schistosomiasis in east Africa. 相似文献
55.
Cefalu WT; Wagner JD; Bell-Farrow AD; Edwards IJ; Terry JG; Weindruch R; Kemnitz JW 《Toxicological sciences》1999,52(2):49-55
Caloric restriction (CR) has been observed to retard aging processes and
extend the maximum life span in rodents. In an effort to evaluate the
effect of this nutritional intervention on physiologic variables in higher
species, several nonhuman primate trials are ongoing. In particular, a
study evaluating the independent effect of CR on the extent of
atherosclerosis was initiated in 1993 in 32 adult cynomolgus monkeys.
Therefore, the trial was designed to achieve identical cholesterol intake
after animals were randomized to a control group or a calorie-restricted
group (30% reduction from baseline caloric intake). The animals were
routinely evaluated for glycated proteins, plasma insulin and glucose
levels, insulin sensitivity, and specific measures for abdominal fat
distribution by CT scans over a 4-year interval. The results from 4 years
of intervention demonstrate that CR improves cardiovascular risk factors
(such as visceral fat accumulation) and improves insulin sensitivity. In
contrast to other primate studies with normolipidemic animals, CR had no
independent effects on plasma lipid levels and composition in the presence
of equivalent amounts of dietary cholesterol intake. Preliminary analysis
of atherosclerotic lesion extent in the abdominal aorta has failed to
demonstrate differences between control animals and CR animals. Follow- up
studies are being conducted to determine the effect of CR on
atherosclerosis extent in coronary and carotid arteries.
相似文献
56.
57.
The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells. 相似文献
58.
Catharina Carolina de Jong Wynand JG Ros Guus Schrijvers 《Journal of medical Internet research》2014,16(1)
Background
In support of professional practice, asynchronous communication between the patient and the provider is implemented separately or in combination with Internet-based self-management interventions. This interaction occurs primarily through electronic messaging or discussion boards. There is little evidence as to whether it is a useful tool for chronically ill patients to support their self-management and increase the effectiveness of interventions.Objective
The aim of our study was to review the use and usability of patient-provider asynchronous communication for chronically ill patients and the effects of such communication on health behavior, health outcomes, and patient satisfaction.Methods
A literature search was performed using PubMed and Embase. The quality of the articles was appraised according to the National Institute for Health and Clinical Excellence (NICE) criteria. The use and usability of the asynchronous communication was analyzed by examining the frequency of use and the number of users of the interventions with asynchronous communication, as well as of separate electronic messaging. The effectiveness of asynchronous communication was analyzed by examining effects on health behavior, health outcomes, and patient satisfaction.Results
Patients’ knowledge concerning their chronic condition increased and they seemed to appreciate being able to communicate asynchronously with their providers. They not only had specific questions but also wanted to communicate about feeling ill. A decrease in visits to the physician was shown in two studies (P=.07, P=.07). Increases in self-management/self-efficacy for patients with back pain, dyspnea, and heart failure were found. Positive health outcomes were shown in 12 studies, where the clinical outcomes for diabetic patients (HbA1c level) and for asthmatic patients (forced expiratory volume [FEV]) improved. Physical symptoms improved in five studies. Five studies generated a variety of positive psychosocial outcomes.Conclusions
The effect of asynchronous communication is not shown unequivocally in these studies. Patients seem to be interested in using email. Patients are willing to participate and are taking the initiative to discuss health issues with their providers. Additional testing of the effects of asynchronous communication on self-management in chronically ill patients is needed. 相似文献59.
Objective To explore the characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods Seven patients with arrhythmogenic right ventricular cardiomyopathy and 34 members of three families were studied. All patients and family members underwent history collection, clinical examination, electrocardiogram (ECG), two-dimensional echocardiography (2-DE) and a signal averaging electrocardiogram. Programmed ventricular stimulation was performed in five patients. Results All patients and family members had normal morphologic characteristics and normal function of the left ventricular by 2-DE. Fourteen persons had abnormal findings indicating ARVC. Five had enlargement of the right ventricular with diffused hypocontractility, eight had thin and systolic bulging in the focal anterior wall with hypokinesia and one had bulging of the inferior wall. Twenty-five persons (seven patients and 18 family members) had abnormal findings in ECG. Positive ventricular late potential was recorded in 13 persons (six patients). Two to three monomorphic ventricular tachycardia (VT) with left bundle branch block (LBBB) configurations were induced in five patients. Ventricular fibrillation was induced in two patients during the electrophysiologic study (EPS). Five patients had very high pacing threshold and/or ineffective pacing in one or many regions of the right ventricle. Two members of one family died suddenly. One member was a dwarf with ARVC. Spontaneous VT with a left bundle branch block (LBBB) configuration was recorded in five patients, polymorphic VT with extremely short coupling interval in one, and premature ventricular complexes with LBBB configuration in 12 (six patients). Conclusion Our familial study strongly suggests that ARVC may be a hereditary disease and it is helpful in the diagnosis and detection of ARVC. The most common manifestations were abnormal structure and function of the right ventricle and abnormal ECG of repolarization and ventricular arrhythmia which originates from the right ventricle. 相似文献
60.