全文获取类型
收费全文 | 1167篇 |
免费 | 91篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 36篇 |
妇产科学 | 34篇 |
基础医学 | 106篇 |
口腔科学 | 4篇 |
临床医学 | 94篇 |
内科学 | 262篇 |
皮肤病学 | 3篇 |
神经病学 | 99篇 |
特种医学 | 29篇 |
外科学 | 210篇 |
综合类 | 39篇 |
一般理论 | 1篇 |
预防医学 | 186篇 |
眼科学 | 11篇 |
药学 | 76篇 |
中国医学 | 5篇 |
肿瘤学 | 56篇 |
出版年
2023年 | 7篇 |
2022年 | 13篇 |
2021年 | 27篇 |
2020年 | 12篇 |
2019年 | 20篇 |
2018年 | 25篇 |
2017年 | 15篇 |
2016年 | 18篇 |
2015年 | 24篇 |
2014年 | 36篇 |
2013年 | 48篇 |
2012年 | 77篇 |
2011年 | 82篇 |
2010年 | 41篇 |
2009年 | 38篇 |
2008年 | 61篇 |
2007年 | 73篇 |
2006年 | 67篇 |
2005年 | 53篇 |
2004年 | 56篇 |
2003年 | 41篇 |
2002年 | 42篇 |
2001年 | 39篇 |
2000年 | 60篇 |
1999年 | 27篇 |
1998年 | 12篇 |
1997年 | 16篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 16篇 |
1991年 | 15篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 17篇 |
1985年 | 6篇 |
1984年 | 18篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1974年 | 4篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1968年 | 2篇 |
排序方式: 共有1259条查询结果,搜索用时 15 毫秒
1.
P. A. Hannan J. A. Khan A. Khan S. Safiullah 《Indian journal of pharmaceutical sciences》2016,78(1):2-7
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form. 相似文献
2.
Danielle E Whittier Elizabeth J Samelson Marian T Hannan Lauren A Burt David A Hanley Emmanuel Biver Pawel Szulc Elisabeth Sornay-Rendu Blandine Merle Roland Chapurlat Eric Lespessailles Andy Kin On Wong David Goltzman Sundeep Khosla Serge Ferrari Mary L Bouxsein Douglas P Kiel Steven K Boyd 《Journal of bone and mineral research》2022,37(3):428-439
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献
3.
4.
5.
The case of a 62-year-old man with benign schwannoma associated with a giant polyp of the esophagus is presented. His initial symptom was dysphagia. The polyp was removed through cervical esophagotomy. He had no recurrence of symptoms 5 years after this procedure. Pathologic examination showed a rare histology. 相似文献
6.
Hannan MM Desmond EP Morlock GP Mazurek GH Crawford JT 《Journal of clinical microbiology》2001,39(2):647-650
Mycobacterium bovis is naturally resistant to the antituberculosis drug pyrazinamide (PZA). To determine whether all Mycobacterium tuberculosis complex isolates demonstrating PZA monoresistance were truly M. bovis, we examined the phenotype and genotype of isolates reported as PZA monoresistant in five counties in California from January 1996 through June 1999. Isolates reported by local laboratories to be PZA monoresistant were sent to the state reference laboratory for repeat susceptibility testing using the BACTEC radiometric method and to the Centers for Disease Control and Prevention for pncA sequencing and PCR-restriction fragment length polymorphism (RFLP) analysis of the oxyR gene. Of 1,916 isolates, 14 were reported as PZA monoresistant and 11 were available for retesting. On repeat testing, 6 of the 11 isolates were identified as PZA-susceptible M. tuberculosis, 1 was identified as PZA-monoresistant M. bovis, and 1 was identified as M. bovis BCG. The three remaining isolates were identified as PZA-monoresistant M. tuberculosis. Sequencing of the pncA and oxyR genes genotypically confirmed the two M. bovis and the six susceptible M. tuberculosis species. Each of the three PZA-monoresistant M. tuberculosis isolates had different, previously unreported, pncA gene mutations: a 24-bp deletion in frame after codon 88, a base substitution at codon 104 (Ser104Cys), and a base substitution at codon 90 (Ile90Ser). This study demonstrates that PZA monoresistance is not an absolute marker of M. bovis species but may also occur in M. tuberculosis, associated with a number of different mutational events in the pncA gene. It is the first report of PZA-monoresistant M. tuberculosis in the United States. 相似文献
7.
Susan J Paxton Dianne Neumark-Sztainer Peter J Hannan Marla E Eisenberg 《Journal of clinical child and adolescent psychology》2006,35(4):539-549
This research examined whether body dissatisfaction prospectively predicted depressive mood and low self-esteem in adolescent girls and boys 5 years later. Participants were early-adolescent girls (n = 440, Time 1 M age = 12.7 years) and boys (n = 366, Time 1 M age = 12.8 years) and midadolescent girls (n = 946, Time 1 M age = 15.8 years) and boys (n = 764, Time 1 M age = 15.9 years). After controlling for Time 1 of the relevant dependent variable, ethnicity, socioeconomic status, and body mass index, Time 1 body dissatisfaction was a unique predictor of Time 2 depressive mood and low self-esteem in early-adolescent girls (depressive mood: F = 4.80, p < .05; self-esteem: F = 9.64, p < .01) and midadolescent boys (depressive mood: F = 12.27, p < .001; self-esteem: F = 9.38, p < .01) but not in early-adolescent boys or midadolescent girls. These findings are consistent with the hypothesis that body dissatisfaction is a risk factor for depressive mood and low self-esteem in both girls and boys but in different phases of adolescence. 相似文献
8.
9.
The effect of smoking at different life stages on bone mineral density in elderly men and women 总被引:6,自引:2,他引:4
D. P. Kiel MD Y. Zhang M. T. Hannan J.J Anderson J. A. Baron D. T. Felson 《Osteoporosis international》1996,6(3):240-248
To assess the effect of smoking on bone mineral density (BMD) at different life stages, to examine whether the effect of smoking differs between men and women, and to discover whether its effect in women differs according to history of estrogen use, a cohort study was carried out with single cross-section measurement of BMD by single and dual photon absorptiometry. The setting was the Framingham Study, a population-based cohort study with over 40 years prospectively collected data on smoking. Subjects (n=1164) consisted of cohort members participating in the 20th biennial Framingham examination (1988–1989). The measurements included in the study were BMD measured at the hip, spine and radius, smoking history ascertained at all Framingham Study examinations since 1948, and other factors affecting BMD (age, weight, estrogen use, caffeine use, alcohol use and physical activity). Neither current smoking, recent (last 10 years) smoking, nor early adulthood smoking resulted in significantly lower BMD at any skeletal site among women who had not taken estrogen. Among women who had taken estrogen, BMD at most sites was lower among current or recent smokers, although the small numbers of smokers made it difficult to find significant differences at all skeletal sites. Among men, a consistently lower BMD at all skeletal sites was observed for smokers regardless of when in their life they smoked (4–15.3% lower), although the effect of smoking during early adulthood was of a lesser magnitude (4–8% lower). Former male smokers who had quit <10 years ago had lower BMD than men who had quit 10 years ago. In conclusion, in women who had used estrogen, BMD was lower in current or recent smokers than it was in non-smokers. In men, smoking at any stage of life had adverse effects on the skeleton that was independent of weight, alcohol or caffeine use, implying other mechanisms for smoking's effect on bone. 相似文献
10.
We report a difference in the response of serum homovanillic acid (HVA) and in the performance of some psychological tasks before and after the administration of testosterone enanthate (TE, 100 or 300 mg/wk) or nandrolone decanoate (ND, 100 or 300 mg/wk) for 6 wk to healthy men. Serum HVA was significantly increased in both the low- and high-dose ND groups, from 8.4 +/- 1.0 and 8.7 +/- 0.5 pmol/ml (mean +/- SE) to 11.6 +/- 1.7 and 10.7 +/- 1.1 pmol/ml respectively. No significant changes in HVA were observed for the groups administered TE, nor in 5-HIAA for any of the groups. The influence of ND on the dopaminergic system, which is reflected in increased serum HVA, appears to be independent from the psychological effects which were produced by both androgens. The only change in psychomotor test performance was an improvement in the first trial of a pegboard task. All subjects except those receiving ND (100 mg/wk) were significantly more optimistic in the prediction of their own performance for all nondominant hand tasks (pegboard and finger tapping). The "hostility" and "resentment and aggression" subscales of the MMPI increased significantly in all groups, more so in the high-dose groups. 相似文献