全文获取类型
收费全文 | 501篇 |
免费 | 32篇 |
国内免费 | 6篇 |
专业分类
儿科学 | 43篇 |
妇产科学 | 5篇 |
基础医学 | 59篇 |
口腔科学 | 10篇 |
临床医学 | 42篇 |
内科学 | 101篇 |
皮肤病学 | 5篇 |
神经病学 | 12篇 |
特种医学 | 87篇 |
外科学 | 40篇 |
综合类 | 12篇 |
预防医学 | 32篇 |
眼科学 | 7篇 |
药学 | 50篇 |
肿瘤学 | 34篇 |
出版年
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 12篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 23篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 18篇 |
2009年 | 18篇 |
2008年 | 13篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 13篇 |
1998年 | 28篇 |
1997年 | 28篇 |
1996年 | 32篇 |
1995年 | 23篇 |
1994年 | 27篇 |
1993年 | 19篇 |
1992年 | 12篇 |
1991年 | 4篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1970年 | 2篇 |
排序方式: 共有539条查询结果,搜索用时 15 毫秒
21.
P D Reaven J B McPhillips E L Barrett-Connor M H Criqui 《Journal of the American Geriatrics Society》1990,38(8):847-854
Plasma lipid and lipoprotein levels were measured in 1,019 men and 1,273 women, aged 50 to 89, who were classified according to whether they reported participation in regular strenuous exercise. In men and women, strenuous exercisers had significantly (P less than .01) higher age-adjusted high-density lipoprotein (HDL) cholesterol levels than nonstrenuous exercisers, and male strenuous exercisers also had lower plasma triglyceride levels. Adjusting for differences in cigarette smoking, alcohol consumption, or obesity did not alter these results. A subgroup of 498 consecutive men and 615 consecutive women that completed a more detailed exercise questionnaire were classified into categories of light, moderate, heavy, or no exercise. In men, age-adjusted HDL cholesterol levels were higher and triglyceride levels lower with higher exercise-intensity categories (P for trend less than .001). In the heavy exercise category, HDL cholesterol levels were 15% higher and plasma triglyceride levels were 41% lower than in the sedentary group. In women, HDL cholesterol levels were significantly higher and triglyceride levels lower at the more moderate levels of exercise. In both genders results among exercise-intensity groups did not change after adjusting for age, cigarette smoking, and alcohol consumption. In men, adjusting for obesity did not significantly alter the intergroup differences, whereas in women adjusting for body mass index or waist-to-hip ratio reduced differences in HDL cholesterol levels between exercising and sedentary participants to nonsignificance. We conclude that exercise levels attainable by older adults may significantly improve HDL cholesterol levels and could theoretically reduce the risk of ischemic heart disease. 相似文献
22.
Eosinophil autofluorescence and its use in isolation and analysis of human eosinophils using flow microfluorometry 总被引:5,自引:1,他引:5
Unstained human eosinophils exhibit unusually bright autofluorescence, which allows them to be distinguished from other leukocytes using fluorescence microscopy. Eosinophil fluorescence is associated with the cytoplasmic granules of the cells. Eosinophil granule extracts, containing an as-yet-undefined eosinophil fluorescence factor, exhibited excitation maxima at 370 nm and 450 nm, with maximum emission at 520 nm. Eosinophils adhering to opsonized parasites in vitro deposit fluorescent material onto the parasite surface. Eosinophil fluorescence was of sufficient intensity to allow the preparation of viable, highly enriched (greater than or equal to 98%), eosinophil suspensions from peripheral blood of normal and eosinophilic donors using a fluorescence- activated cell sorter. Quantitative studies of eosinophil autofluorescence were performed using flow microfluorometry. Fluorescence intensity of blood eosinophils from normal volunteers and eosinophilic patients varied inversely with the log of the donor's absolute eosinophil count regardless of clinical diagnosis. 相似文献
23.
Anniek KD Visser Nisha K Ramakrishnan Antoon TM Willemsen Valentina Di Gialleonardo Erik FJ de Vries Ido P Kema Rudi AJO Dierckx Aren van Waarde 《Journal of cerebral blood flow and metabolism》2014,34(1):118-125
The PET tracer [11C]5-hydroxytryptophan ([11C]5-HTP), which is converted to [11C]5-hydroxytryptamine ([11C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [11C]5-HTP in rat? Male rats were scanned with [11C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [11C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [11C]5-HTP uptake, and the k3. This was unexpected as NSD 1015 directly inhibits the enzyme converting [11C]5-HTP to [11C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [11C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents. 相似文献
24.
Association of granulocyte-macrophage colony-stimulating factor with the crystalloid granules of human eosinophils 总被引:3,自引:1,他引:3
Levi-Schaffer F; Lacy P; Severs NJ; Newman TM; North J; Gomperts B; Kay AB; Moqbel R 《Blood》1995,85(9):2579-2586
We have previously shown that normal-density human peripheral blood eosinophils transcribe and translate mRNA for granulocyte-macrophage colony-stimulating factor (GM-CSF) and that the intracellular distribution was granular as assessed by light microscopy immunocytochemistry. The present study was conducted to confirm this apparent association between GM-CSF and the crystalloid granule using a subcellular fractionation method for human eosinophils and immunogold electron microscopy (EM). Highly purified (> 99%, by negative selection using anti-CD16 immunomagnetic microbeads) human peripheral blood eosinophils were obtained from four asthmatic subjects (not taking systemic medication), homogenized and density fractionated (5 x 10(7) cells/subject) on linear Nycodenz gradients. Twenty-four fractions were collected from each cell preparation and analyzed for marker enzyme activities as well as total protein. Dot blot analysis with specific monoclonal antibodies (MoAbs) was used to detect the eosinophil granule proteins major basic protein (MBP) and eosinophil cationic protein (ECP). An anti-CD9 MoAb was used as an eosinophil plasma membrane marker. Lactate dehydrogenase (LDH) was used as a cytosolic marker. Immunoreactivity for GM-CSF was detected by a specific enzyme-linked immunosorbent assay using a polyclonal antihuman GM-CSF antibody and confirmed by dot blot. GM-CSF coeluted with the cellular fractions containing granule markers (MBP, ECP, eosinophil peroxidase, hexosaminidase, and arylsulphatase), but not those containing cytoplasm (LDH+) or membrane (CD9+) markers. EM examination of pooled fractions associated with the peak of GM-CSF immunoreactivity confirmed that they contained crystalloid and small granules, but not plasma membrane. In addition, quantification, using immunogold labeling with an anti/GM-CSF MoAb, indicated preferential localization of gold particles over the eosinophil granule cores of intact cells. Thus, our results indicate that GM-CSF resides as a granule-associated, stored mediator in unstimulated human eosinophils. 相似文献
25.
Primitive hematopoietic cells released into the peripheral blood (PB) were studied in 50 patients with high-grade non-Hodgkin's lymphoma enrolled in a phase III trial of intensive weekly chemotherapy (VAPEC- B) alone or with granulocyte colony-stimulating factor (G-CSF). Mononuclear cells numbers were monitored and their in vitro growth potential assessed in clonogenic progenitor cell assays and in long- term culture. Total colony-forming cells (granulocyte-macrophage [GM], burst-forming unit, erythroid [BFU-E], Mix-CFC) were increased 40-fold (median) over baseline with chemotherapy alone and 106-fold with chemotherapy and G-CSF after the final dose. CD34+ cells were increased to a median of 4%, equivalent to that in normal bone marrow (BM) controls. Circulating colony-forming cell levels were maximal when the recovering total white blood cell (WBC) count reached 5 to 10 x 10(9)/L. The timing of the maximum was reproducible in individual patients. Therefore the WBC count can be used as a guide to the timing of leukapheresis. PB cells from normal controls' and patients' prechemotherapy were unable to sustain hemopoiesis in two-stage long- term cultures. In contrast, PB cells collected from patients primed with chemotherapy alone or chemotherapy with G-CSF at the time of predicted maximal colony-forming cell release were able to generate and sustain hematopoiesis in long-term cultures at a level comparable or superior to normal BM. These findings indicate that the use of G-CSF after routine outpatient chemotherapy stimulates maximal release of primitive hemopoietic cells into the circulation, including colony- forming cells and long-term culture-initiating cells. Their numbers are comparable with those in normal BM and are such that a single leukapheresis will usually yield enough cells for hemopoietic reconstitution after myeloablative chemotherapy. 相似文献
26.
GL Marseglia S Savasta A Ravelli TM Gaino GR Burgio 《Acta paediatrica (Oslo, Norway : 1992)》1995,84(9):1086-1088
We report the case of a 9-year-old boy with a spinal cord meningioma whose only manifestations were recurrent episodes of chest pain lasting for 2 years. This case shows that spinal cord meningioma should be considered among the possible causative factors of chronic chest pain in childhood. Chest pain, meningioma, spinal tumors 相似文献
27.
Clinical evaluation of biomarkers in Gaucher disease 总被引:1,自引:0,他引:1
Novel or candidate biomarkers require thorough evaluation to establish their utility in a clinical setting. This paper describes an evaluation of several established enzyme markers of Gaucher disease and a newly-described chemokine, pulmonary and activation-regulated chemokine (PARC). The ability of the biomarkers to rank patients with Gaucher disease in order of disease severity and organ bulk, and to reflect changes in key clinical parameters in response to enzyme replacement therapy were evaluated. PARC concentrations were found to be reliably correlated with visceral disease and with key clinical responses to enzyme replacement in an unbiased manner. Unlike chitotriosidase and serum angiotensin-converting enzyme activity, genetic variation in serum PARC did not appear to influence its utility as a biomarker.
Conclusion: For each new candidate biomarker of lysosomal storage diseases, a similar clinical evaluation will be required, though the approach will need to be modified according to the clinical features and natural history of each disorder. 相似文献
Conclusion: For each new candidate biomarker of lysosomal storage diseases, a similar clinical evaluation will be required, though the approach will need to be modified according to the clinical features and natural history of each disorder. 相似文献
28.
Child Behaviour Checklist classification of behaviour disorder 总被引:1,自引:0,他引:1
TM NOLAN L BOND R ADLER L LITTLEFIELD P BIRLESON K MARRIAGE A MAWDSLEY R SALO BJ TONGE 《Journal of paediatrics and child health》1996,32(5):405-411
Objective : The aim of this study was to determine the applicability of the published clinical cut-off scores of the Child Behaviour Checklist (CBCL) for the classification of behaviour disorders.
Methodology : Child Behaviour Checklists were obtained for 1342 subjects newly referred to the six major mental health centres in Melbourne. The normative community sample of 1002 7-, 12- and 15-year-olds was drawn from a school-based asthma prevalence study.
Results : The mean total problem T-score for the children referred to mental health centres was 67 and was above the clinical range for all age groups. Using referral to psychiatric services as the gold standard, the sensitivity and specificity of the CBCL using a cut-off of ≥ 60, was 77.4 and 83.2%, respectively. This compares favourably with the sensitivity of 68% and specificity of 82% for the American sample. Using a cut-off score of ≥ 63, the sensitivity was 70.5% and the specificity was 88.6%. The referred and community samples differed with respect to socio-economic status, family structure and mothers' level of education. Fifty-two per cent of the clinically referred children lived with both parents, compared with 89% of the community sample.
Conclusions : While there are some limitations to this study in terms of both the clinic and community sample, support is provided for the usefulness and applicability of the recommended CBCL cut-off scores in an Australian population. 相似文献
Methodology : Child Behaviour Checklists were obtained for 1342 subjects newly referred to the six major mental health centres in Melbourne. The normative community sample of 1002 7-, 12- and 15-year-olds was drawn from a school-based asthma prevalence study.
Results : The mean total problem T-score for the children referred to mental health centres was 67 and was above the clinical range for all age groups. Using referral to psychiatric services as the gold standard, the sensitivity and specificity of the CBCL using a cut-off of ≥ 60, was 77.4 and 83.2%, respectively. This compares favourably with the sensitivity of 68% and specificity of 82% for the American sample. Using a cut-off score of ≥ 63, the sensitivity was 70.5% and the specificity was 88.6%. The referred and community samples differed with respect to socio-economic status, family structure and mothers' level of education. Fifty-two per cent of the clinically referred children lived with both parents, compared with 89% of the community sample.
Conclusions : While there are some limitations to this study in terms of both the clinic and community sample, support is provided for the usefulness and applicability of the recommended CBCL cut-off scores in an Australian population. 相似文献
29.
30.
KM FOCK JY KANG HS NG TM NG KA GWEE CC LIM 《Journal of gastroenterology and hepatology》1995,10(4):379-382
Roxatidine acetate, a new H2 receptor antagonist, was compared with ranitidine in the treatment of duodenal ulcers in a double-blind multicentre study. Eighty-four patients with endoscopically proven duodenal ulcer were randomized to receive 150 mg roxatidine acetate or 300 mg ranitidine at bedtime. Repeat endoscopy was performed after 4 weeks (25–33 days) and if the ulcer had not healed, another endoscopy was performed after a further 4 weeks of treatment. Using per protocol analysis 73.6% of ulcers treated with roxatidine healed at 4 weeks compared to 72.2% of ulcers treated with ranitidine (P=NS). The healing rates at 8 weeks were 92% with roxatidine and 83.3% with ranitidine (P=NS). Using equivalence tests, the healing rate of roxatidine was found to be equivalent to that of ranitidine within a 20% region. Roxatidine users took significantly less antacids than ranitidine users (P < 0.05). There were no significant adverse effects due to roxatidine or ranitidine. Roxatidine is a safe effective drug in the treatment of duodenal ulcers with a healing rate comparable to that of ranitidine. 相似文献