全文获取类型
收费全文 | 908篇 |
免费 | 77篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 54篇 |
妇产科学 | 13篇 |
基础医学 | 69篇 |
口腔科学 | 16篇 |
临床医学 | 106篇 |
内科学 | 318篇 |
皮肤病学 | 5篇 |
神经病学 | 25篇 |
特种医学 | 162篇 |
外科学 | 43篇 |
综合类 | 27篇 |
预防医学 | 49篇 |
眼科学 | 17篇 |
药学 | 81篇 |
肿瘤学 | 34篇 |
出版年
2021年 | 5篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 18篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 38篇 |
2009年 | 45篇 |
2008年 | 22篇 |
2007年 | 34篇 |
2006年 | 19篇 |
2005年 | 33篇 |
2004年 | 22篇 |
2003年 | 18篇 |
2002年 | 22篇 |
2001年 | 21篇 |
2000年 | 17篇 |
1999年 | 24篇 |
1998年 | 52篇 |
1997年 | 50篇 |
1996年 | 47篇 |
1995年 | 43篇 |
1994年 | 43篇 |
1993年 | 28篇 |
1992年 | 19篇 |
1991年 | 25篇 |
1990年 | 28篇 |
1989年 | 35篇 |
1988年 | 31篇 |
1987年 | 17篇 |
1986年 | 23篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 18篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1970年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有1022条查询结果,搜索用时 15 毫秒
31.
32.
Kahn KL MacLean CH Liu H Rubenstein LZ Wong AL Harker JO Chen WP Fitzpatrick DM Bulpitt KJ Traina SB Mittman BS Hahn BH Paulus HE 《Medical care》2007,45(1):55-65
BACKGROUND: Patients with rheumatoid arthritis (RA) provide an important opportunity for understanding care of patients with a serious chronic condition. OBJECTIVES: We sought to characterize the complexity of care for patients with RA, including metrics describing the patient, the disease, and use of the health care system across time and place. METHODS: We undertook a prospective cohort study of 568 community-dwelling patients with RA by using observational data from clinically detailed telephone interviews at baseline and 2 years later in addition to medical record abstraction. Health status, comorbidity, use of disease-modifying antirheumatic drugs, visits, providers, provider types, encounter settings, and the discontinuity between patients and providers were studied. RESULTS: Within a 12-month window, 568 patients had 8686 outpatient encounters with the health care system with a mean of 3.41 unique providers per patient associated with a mean of 5 primary care and 6 rheumatologist visits. Half did not see a primary care physician, and 20% did not see a rheumatologist during 6-month periods despite their use of potentially toxic drugs, a mean of 4 comorbidities and progressive RA. Over the course of 24 months, 29% of patients changed their primary care provider, and 15% changed their rheumatologist. Patients were moderately impaired with mean SF-12 physical component score 37 (SD, 9). CONCLUSION: Patients with RA have frequent encounters with multiple providers and also frequent discontinuity of care. Recognizing the complexity of the care of patients with a chronic disease across multiple dimensions provides an opportunity to better understand challenges and opportunities in delivering high quality care. 相似文献
33.
34.
C J Bulpitt D G Beevers A Butler E C Coles A E Fletcher D Hunt A D Munro-Faure R Newson P W O'Riordan J C Petrie 《Journal of hypertension》1988,6(8):627-632
A group of hypertensive patients (n = 2855) with an untreated diastolic blood pressure greater than or equal to 90 mmHg were followed in the Department of Health and Social Security (DHSS) Hypertension Care Computing Project (DHCCP) for periods of up to 10 years. During this period 191 of these patients died. Survival was assessed in relation to pretreatment blood pressure levels and blood pressure achieved during treatment. The blood pressure during treatment was a useful predictor of mortality, but the pretreatment pressure was not. After adjusting for age, mortality was particularly related to the height of the systolic and diastolic blood pressure during the second and third years of treatment. In men, age-standardized 5-year mortality was greater than 10% in those with a first year treated systolic pressure greater than 150 mmHg or a diastolic pressure greater than 95 mmHg. In women, age standardized 5-year mortality was greater than 5% with the same levels of treated blood pressure. The longest survival occurred with the lowest bands of treated pressure, i.e. systolic pressure less than 140 and diastolic pressure less than 90 mmHg; the 5-year mortality being less than 7% in men and less than 3% in women. Treated systolic and diastolic pressures were useful in predicting death from ischaemic heart disease (IHD). 相似文献
35.
O'Malley CJ; Rasko JE; Basser RL; McGrath KM; Cebon J; Grigg AP; Hopkins W; Cohen B; O'Byrne J; Green MD; Fox RM; Berndt MC; Begley CG 《Blood》1996,88(9):3288-3298
This report describes the effect of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on platelet production and platelet function in humans. Subjects with advanced solid tumors received PEG-rHuMGDF daily for up to 10 days. There was no increase in circulating platelet count at doses of 0.03 or 0.1 microgram/kg/d by day 12 of study. At doses of 0.3 and 1.0 microgram/kg/d there was a threefold median increase (maximum 10-fold) in platelet count by day 16. The platelets produced in vivo in response to PEG-rHuMGDF showed unchanged aggregation and adenosine triphosphate (ATP)-release responses in in vitro assays. Tests included aggregation and release of ATP in response to adenosine diphosphate (ADP) (10, 5, 2.5, and 1.25 mumol/L), collagen (2 micrograms/mL), thrombin-receptor agonist peptide (TRAP, 10 mumol/L) and ristocetin (1.5 mg/mL). Administration of aspirin to an individual with platelet count of 1,771 x 10(3)/L resulted in the typical aspirin-induced ablation of the normal aggregation and ATP-release response to stimulation with arachidonic acid (0.5 mg/mL), collagen, and ADP (2.5 and 1.25 mumol/L). There was no change in the expression of the platelet-surface activation marker CD62P (P-selectin) nor induction of the fibrinogen binding site on glycoprotein IIb/IIIa as reported by the monoclonal antibody, D3GP3. An elevation of reticulated platelets was evident after 3 days of treatment with PEG-rHuMGDF and preceded the increase in circulating platelet count by 5 to 8 days; this reflected the production of new platelets in response to PEG-rHuMGDF. At later time points, the mean platelet volume (MPV) decreased in a manner inversely proportional to the platelet count. Levels of plasma glycocalicin, a measure of platelet turnover, rose 3 days after the initial increase in the peripheral platelet count. The level of plasma glycocalicin was proportional to the total platelet mass, suggesting that platelets generated in response to PEG-rHuMGDF were not more actively destroyed. Thus, the administration of PEG-rHuMGDF, to humans, increased the circulating platelet count and resulted in fully functional platelets, which showed no detectable increase in reactivity nor alteration in activation status. 相似文献
36.
Quality of life in chronic heart failure: cilazapril and captopril versus placebo. Cilazapril-Captopril Multicentre Group 下载免费PDF全文
Bulpitt CJ Fletcher AE Dössegger L Neiss A Nielsen T Viergutz S 《Heart (British Cardiac Society)》1998,79(6):593-598
OBJECTIVE: To measure quality of life (QOL) in patients with mild to moderate heart failure treated with angiotensin converting enzyme (ACE) inhibitors cilazapril or captopril. DESIGN: Randomised, double blind, placebo controlled, parallel groups trial. SUBJECTS: 367 patients with New York Heart Association (NYHA) heart failure class II (62%), III (36%) or IV (1%). METHODS: Patients were randomised to receive cilazapril 1 mg daily (n = 191) or captopril 25 mg three times daily (n = 90) for 24 weeks, or placebo for 12 weeks followed by cilazapril 1 mg daily for a further 12 weeks (n = 86). If patients had not responded after four weeks cilazapril was increased to 2.5 mg daily and captopril to 50 mg three times daily. QOL was assessed at baseline, 12, and 24 weeks using the sickness impact profile (SIP), the profile of mood states (POMS), the Mahler index of dyspnoea-fatigue, and a health status index (HSI). RESULTS: The physical dimension of the SIP averaged 7 units at baseline and improved after 12 weeks by 2.24 units in the cilazapril group, 2.38 units in the captopril group, and 1.51 units in the placebo group. The difference between drug and placebo was therefore 0.73 units (95% CI -0.86 to 2.32) for cilazapril, and 0.87 units (95% CI -0.96 to 2.70) for captopril, with small non-significant effect sizes (a statistical method for estimating the importance of a treatment related change) of 0.12 and 0.14. Similar results were observed for the total POMS and HSI scores. Although QOL improved more on the ACE inhibitors than on placebo, the effect sizes were not significant (< or = 0.26). CONCLUSIONS: Improvements in QOL in mild to moderate heart failure were small when treated with cilazapril or captopril compared with placebo. 相似文献
37.
Tessa Timmers Rik Ossenkoppele Denise Visser Hayel Tuncel Emma E Wolters Sander CJ Verfaillie Wiesje M van der Flier Ronald Boellaard Sandeep SV Golla Bart NM van Berckel 《Journal of cerebral blood flow and metabolism》2020,40(12):2464
The aim of this study was to investigate the test–retest (TRT) repeatability of various parametric quantification methods for [18F]Flortaucipir positron emission tomography (PET). We included eight subjects with dementia or mild cognitive impairment due to Alzheimer’s disease and six cognitively normal subjects. All underwent two 130-min dynamic [18F]Flortaucipir PET scans within 3 ± 1 weeks. Data were analyzed using reference region models receptor parametric mapping (RPM), simplified reference tissue method 2 (SRTM2) and reference logan (RLogan), as well as standardized uptake value ratios (SUVr, time intervals 40–60, 80–100 and 110–130 min post-injection) with cerebellar gray matter as reference region. We obtained distribution volume ratio or SUVr, first for all brain regions and then in three tau-specific regions-of-interest (ROIs). TRT repeatability (%) was defined as |retest–test|/(average (test + retest)) × 100. For all methods and across ROIs, TRT repeatability ranged from (median (IQR)) 0.84% (0.68–2.15) to 6.84% (2.99–11.50). TRT repeatability was good for all reference methods used, although semi-quantitative models (i.e. SUVr) performed marginally worse than quantitative models, for instance TRT repeatability of RPM: 1.98% (0.78–3.58) vs. SUVr80–100: 3.05% (1.28–5.52), p < 0.001. Furthermore, for SUVr80–100 and SUVr110–130, with higher average SUVr, more variation was observed. In conclusion, while TRT repeatability was good for all models used, quantitative methods performed slightly better than semi-quantitative methods. 相似文献
38.
Bulpitt CJ Beckett NS Peters R Leonetti G Gergova V Fagard R Burch LA Banya W Fletcher AE 《Journal of human hypertension》2012,26(3):157-163
To report blood pressure control in the Hypertension in the Very Elderly Trial, a placebo-controlled trial of hypertensive (systolic blood pressure (SBP) 160-199?mm?Hg, diastolic blood pressure (DBP) <110?mm?Hg) participants over the age of 80 years, given treatment in three steps: indapamide slow release 1.5?mg alone, indapamide plus 2?mg perindopril and indapamide plus 4?mg perindopril. The difference in control between participants with combined systolic and diastolic hypertension (SDH, DBP90?mm?Hg) and those with isolated systolic hypertension (ISH, DBP<90?mm?Hg) is determined together with the effects of increments in the treatment regimen. At 2 years, the active treatment lowered blood pressure by 16.5/6.9?mm?Hg more than that on placebo in participants with SDH and by 19.3/4.8?mm?Hg more in those with ISH. The 2-year falls in pressure on placebo alone were 13.2/8.5?mm?Hg in SDH and 8.2/1.5?mm?Hg in ISH participants. With full titration of active treatment, 62% of SDH participants achieved goal SBP (<150?mm?Hg) by 2 years and 71% of those with ISH. The corresponding results for DBP control (<80?mm?Hg) were 40 and 78%. The addition of active perindopril 2?mg roughly doubled the percentage controlled, as did increasing to 4 from 2?mg. Blood pressure control was good with ISH and better than with SDH. The fall in SBP accounted for the observed 30% reduction in strokes, but the 21% reduction in total mortality and 64% reduction in heart failure were greater than predicted. 相似文献
39.
Elevated numbers of primitive Philadelphia chromosome-positive (Ph+) progenitors, including long-term culture-initiating cells (LTC-IC) as well as colony-forming cells (CFC), have been previously described in the blood of patients with chronic myeloid leukemia (CML) in chronic phase with high white blood cell counts. In the present study, which focused primarily on an analysis of circulating progenitors present in such patients at diagnosis, we discovered the frequent and occasionally exclusive presence of circulating normal (Ph-) LTC-IC, often at levels above those seen for LTC-IC in the blood of normal individuals. The presence of detectable numbers of circulating Ph- LTC-IC was independent of the fact that the same peripheral blood samples also contained elevated numbers of predominantly or exclusively Ph+ CFC. Interestingly, both the Ph+ and Ph- LTC-IC in these samples were CD34+CD71- and variably CD38- and Thy-1+, as previously documented for LTC-IC in normal marrow. Thus, neither CD38 nor Thy-1 expression was useful for discriminating between Ph+ and Ph- LTC-IC in mixed populations. Nevertheless, an association of these phenotypes with LTC- IC function did allow highly enriched (> 5% pure) suspensions of either Ph+ or Ph- LTC-IC to be obtained from selected samples of CML blood in which the initial LTC-IC population was either predominantly Ph+ or Ph- , respectively. These findings suggest that the mechanisms causing mobilization of leukemic stem cells in untreated CML patients may affect their normal counterparts. They also indicate a possible new source of autologous cells for the support of intensive therapy of CML patients. Finally, they provide a method for obtaining the most highly purified populations of Ph+ LTC-IC described to date. This method should be useful for further analyses of the molecular activities of these very primitive neoplastic cells. 相似文献
40.
Hermine A van Duyvenvoorde Julian C Lui Sarina G Kant Wilma Oostdijk Antoinet CJ Gijsbers Mari?tte JV Hoffer Marcel Karperien Marie JE Walenkamp Cees Noordam Paul G Voorhoeve Verónica Mericq Alberto M Pereira Hedi L Claahsen-van de Grinten Sandy A van Gool Martijn H Breuning Monique Losekoot Jeffrey Baron Claudia AL Ruivenkamp Jan M Wit 《European journal of human genetics : EJHG》2014,22(5):602-609
Height is a highly heritable and classic polygenic trait. Recent genome-wide association studies (GWAS) have revealed that at least 180 genetic variants influence adult height. However, these variants explain only about 10% of the phenotypic variation in height. Genetic analysis of short individuals can lead to the discovery of novel rare gene defects with a large effect on growth. In an effort to identify novel genes associated with short stature, genome-wide analysis for copy number variants (CNVs), using single-nucleotide polymorphism arrays, in 162 patients (149 families) with short stature was performed. Segregation analysis was performed if possible, and genes in CNVs were compared with information from GWAS, gene expression in rodents'' growth plates and published information. CNVs were detected in 40 families. In six families, a known cause of short stature was found (SHOX deletion or duplication, IGF1R deletion), in two combined with a de novo potentially pathogenic CNV. Thirty-three families had one or more potentially pathogenic CNVs (n=40). In 24 of these families, segregation analysis could be performed, identifying three de novo CNVs and nine CNVs segregating with short stature. Four were located near loci associated with height in GWAS (ADAMTS17, TULP4, PRKG2/BMP3 and PAPPA). Besides six CNVs known to be causative for short stature, 40 CNVs with possible pathogenicity were identified. Segregation studies and bioinformatics analysis suggested various potential candidate genes. 相似文献