全文获取类型
收费全文 | 420篇 |
免费 | 7篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 7篇 |
妇产科学 | 5篇 |
基础医学 | 34篇 |
口腔科学 | 3篇 |
临床医学 | 19篇 |
内科学 | 62篇 |
皮肤病学 | 9篇 |
神经病学 | 32篇 |
特种医学 | 61篇 |
外科学 | 77篇 |
综合类 | 8篇 |
预防医学 | 31篇 |
眼科学 | 2篇 |
药学 | 17篇 |
肿瘤学 | 59篇 |
出版年
2019年 | 3篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 32篇 |
2005年 | 29篇 |
2004年 | 22篇 |
2003年 | 18篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 16篇 |
1999年 | 19篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1993年 | 2篇 |
1992年 | 10篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 14篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 7篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有427条查询结果,搜索用时 46 毫秒
1.
OBJECTIVE
To compare diabetes care and outcomes among Haitians, African Americans, and non-Hispanic whites.RESEARCH DESIGN AND METHODS
We analyzed data from 715 Haitian, 1,472 African American, and 466 non-Hispanic white adults with diabetes using χ2 testing and multiple logistic regression.RESULTS
Haitians had a higher mean A1C than African Americans (8.2 ± 1.9 vs. 7.7 ± 2.0%) and non-Hispanic whites (7.5 ± 1.7%) (both P < 0.0001). There was no difference in completion of process measures. Haitians were more likely than non-Hispanic whites to have elevated LDL cholesterol or blood pressure. Macrovascular complications were fewer among Haitians than African Americans (adjusted odds ratio 0.35 [95% CI 0.23–0.55]), as were microvascular complications (0.56 [0.41–0.76]). Haitians also had fewer macrovascular (0.32 [0.20–0.50]) and microvascular (0.55 [0.39–0.79]) complications than non-Hispanic whites.CONCLUSIONS
Haitians have worse glycemic control than African Americans or non-Hispanic whites. Future research and interventions to improve diabetes care should target Haitians as a distinct racial/ethnic group.There are 531,000 black individuals of Haitian ancestry living in the U.S. (1). We identified no studies of diabetes care or outcomes in this population. Thus, it is unclear whether Haitians, like African Americans, have a higher mean A1C (2), receive less recommended testing (3), or have higher rates of retinopathy (4), nephropathy (5), or lower extremity amputations (6) than whites. We analyzed data from primary care clinics in the largest safety-net hospital in Massachusetts in order to compare diabetes care and outcomes among Haitians, African Americans, and non-Hispanic whites. 相似文献2.
Seungyoun Jung Brian L. Egleston D. Walt Chandler Linda Van Horn Nola M. Hylton Catherine C. Klifa Norman L. Lasser Erin S. LeBlanc Kenneth Paris John A. Shepherd Linda G. Snetselaar Frank Z. Stanczyk Victor J. Stevens Joanne F. Dorgan 《Breast cancer research : BCR》2015,17(1)
Introduction
During adolescence the breasts undergo rapid growth and development under the influence of sex hormones. Although the hormonal etiology of breast cancer is hypothesized, it remains unknown whether adolescent sex hormones are associated with adult breast density, which is a strong risk factor for breast cancer.Methods
Percentage of dense breast volume (%DBV) was measured in 2006 by magnetic resonance imaging in 177 women aged 25–29 years who had participated in the Dietary Intervention Study in Children from 1988 to 1997. They had sex hormones and sex hormone-binding globulin (SHBG) measured in serum collected on one to five occasions between 8 and 17 years of age. Multivariable linear mixed-effect regression models were used to evaluate the associations of adolescent sex hormones and SHBG with %DBV.Results
Dehydroepiandrosterone sulfate (DHEAS) and SHBG measured in premenarche serum samples were significantly positively associated with %DBV (all Ptrend ≤0.03) but not when measured in postmenarche samples (all Ptrend ≥0.42). The multivariable geometric mean of %DBV across quartiles of premenarcheal DHEAS and SHBG increased from 16.7 to 22.1 % and from 14.1 to 24.3 %, respectively. Estrogens, progesterone, androstenedione, and testosterone in pre- or postmenarche serum samples were not associated with %DBV (all Ptrend ≥0.16).Conclusions
Our results suggest that higher premenarcheal DHEAS and SHBG levels are associated with higher %DBV in young women. Whether this association translates into an increased risk of breast cancer later in life is currently unknown.Clinical trials registration
ClinicalTrials.gov Identifier, April 9, 2007; NCT00458588 October 27, 1999 NCT00000459相似文献3.
The Impact of Social Determinants of Health on Hospitalization in the Veterans Health Administration
4.
5.
Dorgan JF McMahon RP Friedman LA Van Horn L Snetselaar LG Kwiterovich PO Lauer RM Lasser NL Stevens VJ Robson A Cooper SF Chandler DW Franklin FA Barton BA Patterson BH Taylor PR Schatzkin A 《The Journal of clinical endocrinology and metabolism》2006,91(10):3992-3996
CONTEXT: Diet reportedly alters serum sex hormone concentrations in adults, but little is known about the influence of diet during puberty on these hormones. OBJECTIVE: We aimed to determine whether an intervention to lower fat intake during adolescence alters serum sex hormone concentrations and progression through puberty. DESIGN: In 1990-1997, we conducted an ancillary study to the Dietary Intervention Study in Children, a multicenter, randomized, controlled clinical trial to test the safety and efficacy of a cholesterol-lowering dietary intervention in children. PARTICIPANTS: Healthy, prepubertal, 8 to 10 yr olds with elevated low-density lipoprotein cholesterol were randomized to usual care or a behavioral intervention. Of 362 randomized Dietary Intervention Study in Children boys, 354 participated in the ancillary study. Eighty-four percent of boys attended last visits when their median time on trial was 7.1 yr. INTERVENTION: The behavioral intervention continued throughout the duration of the trial and promoted a diet with 28% energy from total fat, less than 8% from saturated fat, 9% or less from polyunsaturated fat, and less than 75 mg cholesterol per 1000 kcal. OUTCOME MEASURES: The main outcome measure for boys formulated before study initiation was non-SHBG bound testosterone concentration. Secondary outcomes included serum total testosterone, dihydrotestosterone, androstenedione, estradiol, estrone, SHBG, and Tanner stage. RESULTS: There were no significant treatment group differences in boys' serum hormone levels, SHBG, or Tanner stages at any individual visit or over the course of the trial when evaluated by longitudinal models. CONCLUSION: Modest reductions in total fat, saturated fat, and possibly energy intake do not alter progression through puberty or serum sex hormone concentrations in adolescent boys. 相似文献
6.
Dr. Abraham Lasser MD PhD William B. Koufman MD 《Digestive diseases and sciences》1977,22(11):965-969
Two cases of adenomyoma of the stomach and a review of previous reports in the literature are presented. Adenomyoma is a benign lesion of the pylorus of the stomach composed of smooth muscle, cysts, and glandular structures lined by tall columnar epithelium, Brunner's glands, and sometimes pancreatic tissue. The histopathological and radiological characteristics of this lesion are discussed. 相似文献
7.
Epinephrine Binding to the Catecholamine Receptor and Activation of the Adenylate Cyclase in Erythrocyte Membranes 下载免费PDF全文
M. Schramm H. Feinstein E. Naim M. Lang M. Lasser 《Proceedings of the National Academy of Sciences of the United States of America》1972,69(2):523-527
Turkey erythrocyte membranes showed specific binding of [(3)H]epinephrine. The concentration of hormone required for half-maximal binding (30 muM) was the same as that required for half-maximal activation of the adenylate cyclase located in the same membrane preparation. The binding reaction at 37 degrees C reached completion during the first minute of incubation, which agrees well with the known rapidity of the biological response to catecholamines. Specific binding was abolished by heating the membranes 1 min at 100 degrees C. Chromatography of the bound (3)H, after its extraction from the membranes, indicated that the hormone had fully retained its chemical structure. Epinephrine binding was inhibited by the beta-adrenergic blocking agent propranolol, which also inhibited the activation of adenylate cyclase by the hormone. The specificity of phenethylamine derivatives in displacing [(3)H]epinephrine from the binding sites showed that a typical catecholamine receptor was responsible for the binding. Displacement of the bound hormone by analogs lacking the catechol group was more extensive at 37 degrees C than at 0 degrees C. Some of the analogs that displaced epinephrine from the binding site caused only a feeble activation of the adenylate cyclase, but were able to inhibit the activation of the enzyme by epinephrine. Thus, binding to a catecholamine receptor on a membrane preparation is an essential, but insufficient, condition to elicit a response. 相似文献
8.
Detection of maternal cells in human umbilical cord blood using fluorescence in situ hybridization 总被引:1,自引:2,他引:1
Cord blood is a potential source of hematopoietic stem cells for transplantation and is being used on a growing number of patients. However, there are concerns that cord blood might be contaminated with maternal cells that could lead to graft-versus-host disease. To ascertain the extent to which maternal cell contamination of cord blood occurs, we examined 49 cord blood samples from male babies for maternal cells by fluorescence in situ hybridization using probes to the X and Y chromosomes. A minimum of 1,000 nuclei were scored from each sample, and maternal cells were found in 7 of the 49 cord bloods, at levels ranging from 0.04% to 1.0%. In addition, in 39 and 27 of the cord blood samples, respectively, we examined the CD8+ and CD34+ cell populations for maternal cells. Maternal cells were found in 5 of the 39 CD8 fractions and in 1 of the 27 CD34 fractions, at levels similar to that found in the unfractionated cord blood. In sum, maternal cells were found in either the unseparated mononuclear fraction or the CD8 or CD34 fractions in 10 of the 49 cord blood samples (20%). These results show that maternal cells are present in a substantial number of cord bloods, and that some of these maternal cells are T cells. 相似文献
9.
10.
M. Villiger J. Goulley M. Friedrich A. Grapin-Botton P. Meda T. Lasser R. A. Leitgeb 《Diabetologia》2009,52(8):1599-1607
Aims/hypothesis Structural and functional imaging of the islets of Langerhans and the insulin-secreting beta cells represents a significant
challenge and a long-lasting objective in diabetes research. In vivo microscopy offers a valuable insight into beta cell function
but has severe limitations regarding sample labelling, imaging speed and depth, and was primarily performed on isolated islets
lacking native innervations and vascularisation. This article introduces extended-focus optical coherence microscopy (xfOCM)
to image murine pancreatic islets in their natural environment in situ, i.e. in vivo and in a label-free condition.
Methods Ex vivo measurements on excised pancreases were performed and validated by standard immunohistochemistry to investigate the
structures that can be observed with xfOCM. The influence of streptozotocin on the signature of the islets was investigated
in a second step. Finally, xfOCM was applied to make measurements of the murine pancreas in situ and in vivo.
Results xfOCM circumvents the fundamental physical limit that trades lateral resolution for depth of field, and achieves fast volumetric
imaging with high resolution in all three dimensions. It allows label-free visualisation of pancreatic lobules, ducts, blood
vessels and individual islets of Langerhans ex vivo and in vivo, and detects streptozotocin-induced islet destruction.
Conclusions/interpretation Our results demonstrate the potential value of xfOCM in high-resolution in vivo studies to assess islet structure and function
in animal models of diabetes, aiming towards its use in longitudinal studies of diabetes progression and islet transplants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users. 相似文献