全文获取类型
收费全文 | 381篇 |
免费 | 19篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 16篇 |
妇产科学 | 5篇 |
基础医学 | 22篇 |
口腔科学 | 20篇 |
临床医学 | 42篇 |
内科学 | 85篇 |
皮肤病学 | 8篇 |
神经病学 | 7篇 |
特种医学 | 50篇 |
外科学 | 23篇 |
综合类 | 13篇 |
预防医学 | 72篇 |
眼科学 | 4篇 |
药学 | 22篇 |
肿瘤学 | 22篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 11篇 |
2011年 | 13篇 |
2010年 | 17篇 |
2009年 | 18篇 |
2008年 | 14篇 |
2007年 | 26篇 |
2006年 | 21篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 9篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
排序方式: 共有418条查询结果,搜索用时 31 毫秒
1.
HIV testing within at-risk populations in the United States and the reasons for seeking or avoiding HIV testing 总被引:6,自引:0,他引:6
Kellerman SE Lehman JS Lansky A Stevens MR Hecht FM Bindman AB Wortley PM 《Journal of acquired immune deficiency syndromes (1999)》2002,31(2):202-210
OBJECTIVES: We determined proportions of high-risk persons tested for HIV, the reasons for testing and not testing, and attitudes and perceptions regarding HIV testing, information that is critical for planning prevention programs. METHODS: Cross-sectional interview study of persons at high risk for HIV infection (men who have sex with men [MSM]; injection drug users [IDUs]; and heterosexual persons recruited from gay bars, street outreach, and sexually transmitted disease clinics) among six states participating in the HIV Testing Survey (HITS) in 1995 to 1996 (HITS-I) and 1998 to 1999 (HITS-II). RESULTS: Overall testing rates were lower in the HITS-I (1226/1599 [77%]) than in the HITS-II (1375/1711 [80%]) (p =.01). Persons <25 years old tested less frequently than those >or=25 years old (HITS-I: 71% vs. 78%, respectively, p=.007; HITS-II: 63% vs. 85%, respectively, p<.001). The main reasons for testing and not testing were the same in both surveys, but the proportions of reasons for not testing differed (e.g., "unlikely exposed to HIV" [HITS-I (17%) vs. HITS-II (30%), p<.0001], "afraid of finding out HIV-positive" [HITS-I (27%) vs. HITS-II (18%), p<.0001]). Attitudes regarding HIV testing differed among tested and untested respondents, especially among MSM. CONCLUSIONS: HIV testing rates were higher in the HITS-II, but testing rates decreased among the youngest respondents. Denial of HIV risk factors and fear of being HIV-positive were the principal reasons for not being tested. Availability of new HIV therapies may have contributed to decreased fear of finding out that one is HIV infected as a reason to avoid testing. The increased proportion of persons at risk who did not test because they believed they were unlikely to have been exposed highlights the need for prevention efforts to address risk perceptions. 相似文献
2.
Yang GC; Croaker D; Zhang AL; Manglick P; Cartmill T; Cass D 《Human molecular genetics》1998,7(6):1047-1052
Lethal white foal syndrome (LWFS) is a congenital anomaly of horses
characterized by a white coat colour and aganglionosis of the bowel, which
is similar to Hirschsprung disease (HSCR). We decided to investigate
possible mutations of the endothelin-B receptor gene ( EDNRB ) in LWFS as
recent studies in mutant rodents and some patients have demonstrated EDNRB
defects. First, we identified a full-length cDNA for horse EDNRB . This
cDNA fragment contained a 1329 bp open reading frame which encoded 443
amino acid residues. The predicted amino acid sequence was 89, 91 and 85%
identical to human, bovine and mouse as well as rat EDNRB respectively, but
only 55% identical to the human, bovine and rat endothelin A receptor
(EDNRA). Secondly, sequence analysis, together with allele-specific PCR and
the amplification- created restriction site (ACRS) technique, revealed a
dinucleotide TC-- >AG mutation, which changed isoleucine to lysine in
the predicted first transmembrane domain of the EDNRB protein. This was
associated with LWFS when homozygous and with the overo phenotype when
heterozygous.
相似文献
3.
Relationship between HLA-DRB1 and DQ alleles and the genetic susceptibility to type 1 diabetes 总被引:6,自引:0,他引:6
Objective To study the relationship between human leukocyte antigen (HLA)-DRB1 and DQ alleles and the genetic susceptibility of type 1 diabetes in North Chinese children. Methods Polymerase chain reaction (PCR) techniques were used to amplify the second exon of DRB1 and DQ alleles, after which sequence specific olignucleotide probe (SSOP) dot blot hybridization techniques were used to analyze the amplified products. Results DRB1*0301, DQA1*0301, DQB1*0201 alleles and DRB1*0301-DQA1*0501-DQB1*0201 haplotype were significantly increased in patients, while DQA1*0103 and DQB1*0601 alleles were significantly increased in controls. The distribution of DR4 and DR9 haplotypes in patients and controls were not significantly different, but DR3/DR4 and DR4/DR9 heterozygotes were significantly increased in patients. Conclusions DRB1*0301, DQA1*0301 and DQB1*0201 confer susceptibility while DQA1*0103 and DQB1*0601 confer protection to type 1 diabetes. DRB1*0301-DQA1*0501-DQB1*0201 haplotype offers a predisposition to type 1 diabetes in North Chinese. Although the distribution of DR4 and DR9 in patients and controls had no significant difference, DR3/DR4 and DR3/DR9 heterozygotes were significantly increased in patients, showing that the susceptive effects of DR3 and DR4 or DR4 and DR9 haplotypes could be added up. 相似文献
4.
We report our clinical experience with phototherapy in 3802 infants; 3629 were exposed to "standard" daylight phototherapy and 173 to "high-intensity" blue-light phototherapy. High-intensity blue-light phototherapy was twice as effective as standard daylight phototherapy in decreasing bilirubin concentrations. No failures occurred with high-intensity phototherapy compared with an overall failure rate of 1.84/1000 with daylight lamps; these cases were transferred to high-intensity phototherapy with prompt response. Rebound after cessation of phototherapy was greater in those exposed to high-intensity blue light with a significantly greater number requiring a second exposure. However, the incidence was still low. No third exposure was required in any infant. Nursing of infants under high-intensity blue light was more difficult and inconvenient as was clinical monitoring. The light also caused more stress on the nursing and medical personnel. However, the infants tolerated both types of phototherapy equally well. High-intensity blue-light phototherapy would seem to be the treatment of choice for infants with rapidly increasing or very high bilirubin levels, as well as in those not responding adequately to daylight phototherapy. 相似文献
5.
Informed consent, parental awareness, and reasons for participating in a randomised controlled study
M van Stuijvenberg MH Suur S de Vos GC Tjiang EW Steyerberg G Derksen-Lubsen HA Moll 《Archives of disease in childhood》1998,79(2):120-125
BACKGROUND: The informed consent procedure plays a central role in randomised controlled trials but has only been explored in a few studies on children. AIM: To assess the quality of the informed consent process in a paediatric setting. METHODS: A questionnaire was sent to parents who volunteered their child (230 children) for a randomised, double blind, placebo controlled trial of ibuprofen syrup to prevent recurrent febrile seizures. RESULTS: 181 (79%) parents responded. On average, 73% of parents were aware of the major study characteristics. A few had difficulty understanding the information provided. Major factors in parents granting approval were the contribution to clinical science (51%) and benefit to the child (32%). Sociodemographic status did not influence initial participation but west European origin of the father was associated with willingness to participate in future trials. 89% of participants felt positive about the informed consent procedure; however, 25% stated that they felt obliged to participate. Although their reasons for granting approval and their evaluation of the informed consent procedure did not differ, relatively more were hesitant about participating in future. Parents appreciated the investigator being on call 24 hours a day (38%) and the extra medical care and information provided (37%) as advantages of participation. Disadvantages were mainly the time consuming aspects and the work involved (23%). CONCLUSIONS: Parents' understanding of trial characteristics might be improved by designing less difficult informed consent forms and by the investigator giving extra attention and information to non-west European parents. Adequate measures should be taken to avoid parents feeling obliged to participate, rather than giving true informed consent. 相似文献
6.
A monokine regulates colony-stimulating activity production by vascular endothelial cells 总被引:20,自引:0,他引:20
Human umbilical vein endothelial cells were cultured in supernatants of peripheral blood monocytes that had been cultured for 3 days with and without lactoferrin. Colony-stimulating activity (CSA) was measured in supernatants of the endothelial cell cultures and appropriate control cultures using normal, T-lymphocyte-depleted, phagocyte-depleted, low- density bone marrow cells in colony growth (CFU-GM) assays. Monocyte- conditioned medium contained a nondialyzable, heat labile factor that enhanced 4-15--fold the production of CSA by endothelial cells. The addition of lactoferrin to monocyte cultures reduced the activity of this monokine by 69%. Lactoferrin did not inhibit CSA production by monokine-stimulated endothelial cells. Therefore, vascular endothelial cells are potent sources of CSA, the production of CSA by these cells is regulated by a stimulatory monokine, and the production and/or release of the monokine is inhibited by lactoferrin, a neutrophil- derived putative feedback inhibitor of granulopoiesis. Inasmuch as a similar monokine is known to stimulate CSA production by fibroblasts and T lymphocytes, we suggest that mononuclear phagocytes play a pivotal role in the regulation of granulopoiesis by recruiting a variety of cell types to produce CSA. 相似文献
7.
Genetic deletion of ghrelin does not decrease food intake but influences metabolic fuel preference 总被引:18,自引:0,他引:18
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wortley KE Anderson KD Garcia K Murray JD Malinova L Liu R Moncrieffe M Thabet K Cox HJ Yancopoulos GD Wiegand SJ Sleeman MW 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(21):8227-8232
Ghrelin is a recently identified growth hormone (GH) secretogogue whose administration not only induces GH release but also stimulates food intake, increases adiposity, and reduces fat utilization in mice. The effect on food intake appears to be independent of GH release and instead due to direct activation of orexigenic neurons in the arcuate nucleus of the hypothalamus. The effects of ghrelin administration on food intake have led to the suggestion that inhibitors of endogenous ghrelin could be useful in curbing appetite and combating obesity. To further study the role of endogenous ghrelin in appetite and body weight regulation, we generated ghrelin-deficient (ghrl(-/-)) mice, in which the ghrelin gene was precisely replaced with a lacZ reporter gene. ghrl(-/-) mice were viable and exhibited normal growth rates as well as normal spontaneous food intake patterns, normal basal levels of hypothalamic orexigenic and anorexigenic neuropeptides, and no impairment of reflexive hyperphagia after fasting. These results indicate that endogenous ghrelin is not an essential regulator of food intake and has, at most, a redundant role in the regulation of appetite. However, analyses of ghrl(-/-) mice demonstrate that endogenous ghrelin plays a prominent role in determining the type of metabolic substrate (i.e., fat vs. carbohydrate) that is used for maintenance of energy balance, particularly under conditions of high fat intake. 相似文献
8.
Objective
The purpose of this study was to eliminate orthodontic treatment in mild to moderate cases of condylar hyperplasia in its early stages by condylectomy.Patients and methods
A total of five patients (two females and three males) aged between 17 and 40 years were treated with unilateral condylectomy of the involved side without orthodontic treatment. All patients underwent standardized clinical and radiological examination at initial consultation, before surgery, immediately after surgery, and follow-up. Objective and subjective evaluation of temporomandibular joint (TMJ) included maximal incisal opening, lateral excursions, correction of facial asymmetry, occlusal harmony, TMJ pain, and jaw function. Results were recorded at 5-year follow-up.Results
In all our cases, we achieved good mouth opening and near to normal occlusion. Good facial aesthetics was obtained after 3 months postoperative follow-up without secondary orthodontic treatment.Conclusion
Thus, we conclude that treatment of mild to moderate cases of unilateral condylar hyperplasia during the inactive phase can be treated with condylectomy without orthodontic treatment, and it significantly improves long-term surgical outcomes. 相似文献9.
10.
Antony George Attokaran FRACP FCICM Mahesh Ramanan MMed FCICM Lisa Hunt MBBS Kavita Chandra MBBS Rajbir Sandha FACEM Stacey Watts RN BN GC Balasubramanian Venkatesh MD FCICM FAHMS 《Emergency medicine Australasia : EMA》2023,35(4):657-663