全文获取类型
收费全文 | 1031篇 |
免费 | 42篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 38篇 |
妇产科学 | 11篇 |
基础医学 | 96篇 |
口腔科学 | 15篇 |
临床医学 | 87篇 |
内科学 | 192篇 |
皮肤病学 | 191篇 |
神经病学 | 14篇 |
特种医学 | 249篇 |
外科学 | 53篇 |
综合类 | 17篇 |
预防医学 | 29篇 |
眼科学 | 7篇 |
药学 | 35篇 |
1篇 | |
中国医学 | 8篇 |
肿瘤学 | 31篇 |
出版年
2021年 | 9篇 |
2020年 | 3篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 19篇 |
2012年 | 31篇 |
2011年 | 49篇 |
2010年 | 36篇 |
2009年 | 36篇 |
2008年 | 20篇 |
2007年 | 30篇 |
2006年 | 30篇 |
2005年 | 26篇 |
2004年 | 9篇 |
2003年 | 23篇 |
2002年 | 22篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 18篇 |
1998年 | 48篇 |
1997年 | 34篇 |
1996年 | 38篇 |
1995年 | 46篇 |
1994年 | 40篇 |
1993年 | 38篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 13篇 |
1989年 | 45篇 |
1988年 | 31篇 |
1987年 | 36篇 |
1986年 | 43篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 15篇 |
1981年 | 19篇 |
1980年 | 18篇 |
1979年 | 9篇 |
1978年 | 15篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1975年 | 15篇 |
1959年 | 2篇 |
1958年 | 4篇 |
1957年 | 6篇 |
1954年 | 2篇 |
排序方式: 共有1077条查询结果,搜索用时 15 毫秒
21.
22.
OBJECTIVES: To investigate maternal knowledge and attitudes about otitis media (OM) risk, to estimate the prevalence of risk factors in the first year of life, and to identify barriers to the reduction of risk factors (eg, formula feeding, day care attendance, and exposure to passive smoke). METHODS: Questionnaires mailed to a systematic sample of 504 Minnesota women >/=18 years old identified through 1994 birth certificates. RESULTS: Eighty percent returned a completed survey. According to maternal report, 29% of infants (age 8 to 13 months) had recurrent OM (>/=3 episodes) and 2% had tympanostomy tubes. Forty-six percent attended day care, 29% had >/=1 smoking parent, and 49% breastfed for =2 months. Women were more knowledgeable about OM signs and symptoms than about risk factors. Mean OM knowledge score (the sum of correct true-false responses) was 7.0 (standard deviation = 1.6). Using multiple linear regression, knowledge score was significantly related to marital status, education, age, area of residence, breastfeeding (months), and number of cigarettes smoked per day by the mother, but not to infant or sibling OM history or day care attendance (R = .23). Infant history of OM (odds ratio, 1.9; 95% confidence interval, 1.1 to 3.2) and white race (odds ratio, 0.3; 95% confidence interval, 0. 1 to 0.8), but not the presence of risk factors, were significantly related to having received clinicians' advice about OM prevention advice. CONCLUSION: OM education and prevention programs should target pregnant women and new mothers with OM risk factors, and those who are young, single, and less educated. 相似文献
23.
Hansen LA; Malarkey DE; Wilkinson JE; Rosenberg M; Woychik RE; Tennant RW 《Carcinogenesis》1998,19(10):1837-1845
We previously reported that papillomas can arise from the follicular
epithelium of v-Ha-ras transgenic TGxAC mice. Since the viable-yellow
mutation (A(vy)) of the mouse agouti gene which regulates coat color
pigmentation by acting within the micro-environment of the hair follicle
has been shown to function as a tumor promoter in the liver, we
hypothesized that it may also play a role in TGxAC skin tumorigenesis.
Endogenous agouti protein product was detected in the outer root sheath of
anagen hair follicles following plucking of the hair shaft, but not in the
interfollicular epithelium, in TGxAC mice on an FVB/N genetic background.
It was also detected in papillomas from these mice produced by
12-O-tetradecanoylphorbol-13-acetate (TPA) treatment or plucking.
Expression of the A(vy) allele in the v-Ha-ras transgenic TGxAC mouse line
results in an approximately 2-fold increase in papilloma development
compared with controls which did not carry the A(vy) allele following
twice-weekly treatment with 1.25, 2.5 or 5.0 microg TPA. In addition,
TPA-treated, papilloma-bearing F1 mice which carried the A(vy) allele, but
not F1 mice which did not carry the A(vy) allele, exhibited a syndrome of
humoral hypercalcemia mediated by parathyroid hormone-related protein
(PTHrP) that led to weight loss, hypercalcemia and hypophosphatemia. Thus,
we conclude that the A(vy) allele can influence the development of skin
tumors and PTHrP-mediated humoral hypercalcemia in v-Ha-ras transgenic
TGxAC mice.
相似文献
24.
Dáfne Cardoso Bourguignon da Silva Gláucia Toribio Finoti Seixas Orlei Ribeiro de Araujo Rodrigo Genaro Arduini Fabianne Altruda de Moraes Costa Carlesse Antonio Sergio Petrilli 《The Brazilian journal of infectious diseases》2012,16(4):361-365
BackgroundUsual treatment regimens with vancomycin often fail to provide adequate serum levels in patients with severe infections.MethodsRetrospective analysis of vancomycin trough serum measurements. The following parameters were calculated by Bayesian analysis: vancomycin clearance, distribution volume, and peak estimated concentrations. The area under the concentration curve (AUC) (total daily dose/24 h clearance of vancomycin) was used to determine the effectiveness of treatment through the ratio of AUC/minimum inhibitory concentration (MIC) above 400, using MIC = 1 μg/mL, based on isolates of Staphylococci in cultures.ResultsSixty-one vancomycin trough measurements were analyzed in 31 patients. AUC/MIC > 400 was obtained in 34 out of 61 dosages (55.7%), but the mean vancomycin dose required to achieve these levels was 81 mg/kg/day. In cases where the usual doses were administered (40–60 mg/kg/day), AUC/MIC > 400 was obtained in nine out of 18 dosages (50%), in 13 patients. Trough serum concentrations above 15 mg/L presented a positive predictive value of 100% and a negative predictive value of 71% for AUC/MIC > 400.ConclusionHigher than usual vancomycin doses may be required to treat staphylococcal infections in children with oncologic/hematologic diseases. Since the best known predictor of efficacy is the AUC/MIC ratio, serum trough concentrations must be analyzed in conjunction with MICs of prevalent Staphylococci and pharmacokinetic tools such as Bayesian analysis. 相似文献
25.
26.
有越来越多的医生选择学习在线课程来进行继续医学教育,但却很少有严格的评估方法来确定在线继续医学教育活动的效果.鉴于此,美国阿拉巴马大学医学院继续医学教育部的研究人员进行了相关研究.应用时间序列设计的方法,来比较完成了继续医学教育网站提供的任意30分钟在线继续医学教育课程的医生在教育活动前后其知识、态度和自我报告的在临床实践中诊疗行为的变化. 相似文献
27.
Ortiz-Alvarez O; Cabral D; Prendiville JS; Stringer D; Petty RE; Malleson PN 《Rheumatology (Oxford, England)》1997,36(2):280-284
Two children are reported in whom intestinal pseudo-obstruction was the
initial manifestation of systemic sclerosis. Gastrointestinal symptoms and
skin changes resolved or improved in both children following treatment with
prednisone and penicillamine (case 1) or methotrexate (case 2), although
radiological changes of the gastrointestinal tract persisted at 3 and 2 yr
of follow-up, respectively.
相似文献
28.
Jacqueline AM Smith DL Patil OT Daniels Y-S Ding J-D Gallezot S Henry KHS Kim S Kshirsagar WJ Martin GP Obedencio E Stangeland PR Tsuruda W Williams RE Carson ST Patil 《The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP)》2015,18(2)
Background:
Monoamine reuptake inhibitors exhibit unique clinical profiles that reflect distinct engagement of the central nervous system (CNS) transporters.Methods:
We used a translational strategy, including rodent pharmacokinetic/pharmacodynamic modeling and positron emission tomography (PET) imaging in humans, to establish the transporter profile of TD-9855, a novel norepinephrine and serotonin reuptake inhibitor.Results:
TD-9855 was a potent inhibitor of norepinephrine (NE) and serotonin 5-HT uptake in vitro with an inhibitory selectivity of 4- to 10-fold for NE at human and rat transporters. TD-9855 engaged norepinephrine transporters (NET) and serotonin transporters (SERT) in rat spinal cord, with a plasma EC50 of 11.7ng/mL and 50.8ng/mL, respectively, consistent with modest selectivity for NET in vivo.Accounting for species differences in protein binding, the projected human NET and SERT plasma EC50 values were 5.5ng/mL and 23.9ng/mL, respectively. A single-dose, open-label PET study (4–20mg TD-9855, oral) was conducted in eight healthy males using the radiotracers [11C]-3-amino-4- [2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzonitrile for SERT and [11C]-(S,S)-methylreboxetine for NET. The long pharmacokinetic half-life (30–40h) of TD-9855 allowed for sequential assessment of SERT and NET occupancy in the same subject. The plasma EC50 for NET was estimated to be 1.21ng/mL, and at doses of greater than 4mg the projected steady-state NET occupancy is high (>75%). After a single oral dose of 20mg, SERT occupancy was 25 (±8)% at a plasma level of 6.35ng/mL.Conclusions:
These data establish the CNS penetration and transporter profile of TD-9855 and inform the selection of potential doses for future clinical evaluation. 相似文献29.
30.