全文获取类型
收费全文 | 575篇 |
免费 | 49篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 74篇 |
妇产科学 | 11篇 |
基础医学 | 52篇 |
口腔科学 | 38篇 |
临床医学 | 66篇 |
内科学 | 147篇 |
皮肤病学 | 10篇 |
神经病学 | 32篇 |
特种医学 | 73篇 |
外科学 | 42篇 |
综合类 | 9篇 |
一般理论 | 1篇 |
预防医学 | 28篇 |
眼科学 | 4篇 |
药学 | 30篇 |
肿瘤学 | 14篇 |
出版年
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 12篇 |
2014年 | 10篇 |
2013年 | 21篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 21篇 |
2009年 | 18篇 |
2008年 | 15篇 |
2007年 | 21篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 22篇 |
1997年 | 38篇 |
1996年 | 34篇 |
1995年 | 21篇 |
1994年 | 24篇 |
1993年 | 22篇 |
1992年 | 7篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 17篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 16篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1968年 | 4篇 |
排序方式: 共有632条查询结果,搜索用时 344 毫秒
61.
62.
P K Nelms O Larson D Barnes-Josiah 《Public health reports (Washington, D.C. : 1974)》1997,112(3):240-244
OBJECTIVE: To determine the cause of illnesses experienced by employees of a Minneapolis manufacturing plant after drinking hot chocolate bought from a vending machine and to explore the prevalence of similar vending machine-related illnesses. METHODS: The authors inspected the vending machines at the manufacturing plant where employees reported illnesses and at other locations in the city where hot chocolate beverages were sold in machines. Tests were performed on dry mix, water, and beverage samples and on machine parts. RESULTS: Laboratory analyses confirmed the presence of B. cereus in dispensed beverages at a concentration capable of causing illness (170,000 count/gm). In citywide testing of vending machines dispensing hot chocolate, 7 of the 39 licensed machines were found to be contaminated, with two contaminated machines having B. cereus levels capable of causing illness. CONCLUSIONS: Hot chocolate sold in vending machines may contain organisms capable of producing toxins that under favorable conditions, can induce illness. Such illnesses are likely to be underreported. Even low concentrations of B. cereus may be dangerous for vulnerable populations such as the aged or immunosuppressed. Periodic testing of vending machines is thus warranted. The relationship between cleaning practices and B. cereus contamination is an issue for further study. 相似文献
63.
64.
65.
66.
Hospital Inpatient Admissions With Dehydration and/or Malnutrition in Medicare Beneficiaries Receiving Enteral Nutrition: A Cohort Study 下载免费PDF全文
Rachel Drake MS RD CSO CSP CNSC CD‐N Audrey Ozols MBA William J. Nadeau MS RD CNSC Mary Jo Braid‐Forbes MPH 《JPEN. Journal of parenteral and enteral nutrition》2018,42(4):730-738
Background: Enteral nutrition (EN) supports many older and disabled Americans. This study describes the frequency and cost of acute care hospitalization with dehydration and/or malnutrition of Medicare beneficiaries receiving EN, focusing on those receiving home EN. Methods: Medicare 5% Standard Analytic Files were used to determine Medicare spending for EN supplies and the proportion and cost of beneficiaries receiving EN, specifically home EN, admitted to the hospital with dehydration and/or malnutrition. Results: In 2013, Medicare paid $370,549,760 to provide EN supplies for 125,440 beneficiaries, 55% of whom were also eligible for Medicaid. Acute care hospitalization with dehydration and/or malnutrition occurred in 43,180 beneficiaries receiving EN. The most common principal diagnoses were septicemia (21%), aspiration pneumonitis (9%), and pneumonia (5%). In beneficiaries receiving EN at home, >one‐third (37%) were admitted with dehydration and/or malnutrition during a mean observation interval of 231 ± 187 days. Admitted patients were usually hospitalized more than once with dehydration and/or malnutrition (1.73 ± 1.30 admissions) costing $23,579 ± 24,966 per admitted patient, totaling >$129,685,622 during a mean observation interval of 276 ± 187 days. Mortality in the year following enterostomy tube placement was significantly higher for admitted compared with nonadmitted patients (40% vs 33%; P = .05). Conclusion: Acute care hospitalizations with dehydration and/or malnutrition in Medicare beneficiaries receiving EN were common and expensive. Additional strategies to reduce these, with particular focus on vulnerable populations such as Medicaid‐eligible patients, are needed. 相似文献
67.
Function of wild-type or mutant Rac2 and Rap1a GTPases in differentiated HL60 cell NADPH oxidase activation 总被引:5,自引:1,他引:5
Studies of neutrophil nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation in a cell-free system showed that the low molecular-weight guanosine triphosphatase (GTPase) Rac was required, and that Rap1a may participate in activation of the catalytic complex. Full-length posttranslationally modified Rac2 was active, whereas only the 1-166 truncated form of Rap1a was functional in the cell-free system, and thus, clarification of the function of Rap1a and Rac2 in intact human phagocytes is needed to provide further insight into their roles as signal transducers from plasma membrane receptors. In the present studies, oligonucleotide-directed mutagenesis was used to introduce a series of mutations into human rap1a or rac2 in the mammalian expression vector pSR alpha neo. HL60 cells transfected with wild-type or mutated rac2 or rap1a cDNA constructs and control HL60 cells transfected with the pSR alpha neo vector containing no inserted cDNA were selected in G418-containing media, then subclones were isolated. Compared with the parent HL60 cells, each of the stable transfected cell lines differentiated similarly into neutrophil-like cells and expressed comparable levels of NADPH oxidase components p47- phox, p67-phox and gp91-phox. The differentiated vector control cell line produced O2. in response to receptor stimulation at rates that were not significantly different from parent HL60 cells. O2-. production by differentiated cell lines expressing mutated N17 Rap1a or N17 Rac2 dominant-negative proteins was inhibited, whereas O2-. production by the subline overexpressing wild-type Rap1a was increased by fourfold. O2-. production by the differentiated cell line expressing GTPase-defective V12 Rap1a was also significantly inhibited, a finding that is consistent with a requirement for cycling between guanosine diphosphate- and GTP-bound forms of Rap1a for continuous NADPH oxidase activation in intact neutrophils. A model is proposed in which Rac2 mediates assembly of the p47 and p67 oxidase components on the cytosolic face of the plasma membrane via cytoskeletal reorganization, whereas Rap1a functions downstream as the final activation switch involving direct physical interaction with the transmembrane flavocytochrome component of the NADPH oxidase. 相似文献
68.
Unrelated donor marrow transplantation in children 总被引:3,自引:10,他引:3
Balduzzi A; Gooley T; Anasetti C; Sanders JE; Martin PJ; Petersdorf EW; Appelbaum FR; Buckner CD; Matthews D; Storb R 《Blood》1995,86(8):3247-3256
Eighty-eight children 0.5 to 17 years of age (median, 9 years of age) received an unrelated donor marrow transplant for treatment of chronic myeloid leukemia (CML; n = 16), acute lymphoblastic leukemia (ALL) in first or second remission (n = 15) or more advanced stage (n = 28), acute myeloid leukemia (AML; n = 13), or other hematologic diseases (n = 16) between June 1985 and April 1993. All patients were conditioned with cyclophosphamide and total body irradiation and received a combination of methotrexate and cyclosporine as graft-versus-host disease (GVHD) prophylaxis. Fourty-six patients received transplants from HLA-identical donors and 42 patients received transplants from donors who were minor-mismatched at one HLA-A or B or D/DRB1 locus. The Kaplan-Meier estimates of disease-free survival and relapse were 75% and 0% for patients with CML, 47% and 20% for ALL in first or second remission, 10% and 60% for ALL in relapse or third remission, 46% and 46% for AML in first remission (n = 1) or more advanced disease (n = 12), and 29% and 69% for other diseases. HLA disparity was not significantly associated with lower disease-free survival, but the results suggest more relapses in HLA-matched recipients and there was significantly more transplant-related mortality in mismatched recipients (51% v 24%, P = .04). Most deaths were due to infections associated with acuteor chronic GVHD and occurred within the first 2 years after transplantation. Granulocyte engraftment occurred in all evaluable patients. Sixty-three percent of HLA-matched and 57% of HLA- mismatched recipients were discharged home disease-free at a median of 98 and 103 days, respectively, after transplantation (P = not significant [NS]). The incidence of grades II-IV acute GVHD was 83% in HLA-matched and 98% in HLA-mismatched recipients (P = .009). The incidence of chronic GVHD was 60% in HLA-matched and 69% in HLA- mismatched recipients (P = NS). One or multiple late adverse events such as cataracts, osteonecrosis of the hip or knee, restrictive or obstructive pulmonary disease, and hypothyroidism have occurred in 11 of 33 (33%) surviving patients. Immunosuppression was discontinued in 58% of surviving patients, including all 12 patients surviving more than 3.2 years, all of whom have a Lansky or Karnofsky score of 100%.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
69.
Studies on levamisole--induced agranulocytosis 总被引:1,自引:0,他引:1
Thompson JS; Herbick JM; Klassen LW; Severson CD; Overlin VL; Blaschke JW; Silverman MA; Vogel CL 《Blood》1980,56(3):388-396
Widespread clinical trials of leavo-tetramisole (levamisole) as an immunopotentiating agent in rheumatoid arthritis, metastatic carcinoma, and immunodeficiency states have been complicated by agranulocytosis (AGC) in 2.5%-13% of patients. Other than a relationship with prolonged high dosage, very little is known regarding the pathogenesis of levamisole-induced AGC. Whereas leukoagglutination was negative, fluorochromatic microgranulocytotoxicity (GCY) tests were positive with serum from 10 of 10 acutely neutropenic patients. The antibody was IgM, reacted with 100% of unrelated granulocytes, but not with T or B lymphocytes. Some sera also reacted with monocytes and the myeloid cell line, K-562. Tests for antigen-antibody complexes or cold autoantibodies were negative. Although clinical evidence strongly suggests a haptene (drug) mechanism, in vitro mixing experiments were also negative. An alternative choice parallels the model of aldomet- induced Coombs'-positive hemolytic anemia. Finally, GCY first became positive 2-3 mo prior to the onset of AGC on two patients, suggesting the possibility of identifying those at risk well before the onset of neutropenia. 相似文献
70.
Deeg HJ; Storb R; Thomas ED; Appelbaum F; Buckner CD; Clift RA; Doney K; Johnson L; Sanders JE; Stewart P; Sullivan KM; Witherspoon RP 《Blood》1983,61(5):954-959
Eight patients with Fanconi's anemia were given cyclophosphamide alone (seven patients) or combined with procarbazine and antithymocyte globulin (one patient) followed by marrow grafts from HLA-identical siblings. All patients had engraftment. Seven developed acute and three chronic graft-versus-host disease (GVHD). Three patients died with GVHD and infectious complications (days 19, 56, and 82) and one with an intracerebral hemorrhage (day 540). Four patients are surviving 647- 3435 days after grafting, two are well, and two have chronic GVHD that is improving. These results show that Fanconi's anemia can be treated successfully by allogeneic marrow transplantation. 相似文献