全文获取类型
收费全文 | 3397篇 |
免费 | 267篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 65篇 |
妇产科学 | 76篇 |
基础医学 | 536篇 |
口腔科学 | 87篇 |
临床医学 | 359篇 |
内科学 | 771篇 |
皮肤病学 | 45篇 |
神经病学 | 318篇 |
特种医学 | 99篇 |
外科学 | 370篇 |
综合类 | 30篇 |
一般理论 | 2篇 |
预防医学 | 370篇 |
眼科学 | 40篇 |
药学 | 176篇 |
中国医学 | 2篇 |
肿瘤学 | 311篇 |
出版年
2023年 | 22篇 |
2022年 | 33篇 |
2021年 | 59篇 |
2020年 | 63篇 |
2019年 | 89篇 |
2018年 | 74篇 |
2017年 | 74篇 |
2016年 | 86篇 |
2015年 | 92篇 |
2014年 | 113篇 |
2013年 | 157篇 |
2012年 | 264篇 |
2011年 | 221篇 |
2010年 | 122篇 |
2009年 | 151篇 |
2008年 | 215篇 |
2007年 | 221篇 |
2006年 | 179篇 |
2005年 | 166篇 |
2004年 | 159篇 |
2003年 | 162篇 |
2002年 | 151篇 |
2001年 | 78篇 |
2000年 | 66篇 |
1999年 | 64篇 |
1998年 | 25篇 |
1997年 | 16篇 |
1996年 | 27篇 |
1995年 | 22篇 |
1994年 | 23篇 |
1993年 | 16篇 |
1992年 | 41篇 |
1991年 | 50篇 |
1990年 | 34篇 |
1989年 | 24篇 |
1988年 | 32篇 |
1987年 | 40篇 |
1986年 | 25篇 |
1985年 | 24篇 |
1984年 | 21篇 |
1983年 | 19篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1976年 | 9篇 |
1973年 | 9篇 |
1972年 | 10篇 |
1970年 | 8篇 |
排序方式: 共有3676条查询结果,搜索用时 15 毫秒
1.
Lauren Tingey Britta Mullany Rachel Chambers Ranelda Hastings Angelita Lee Anthony Parker 《AIDS care》2015,27(9):1087-1097
Potential for widespread transmission of HIV/AIDS among American Indian (AI) adolescents exists, yet no evidence-based interventions (EBIs) have been adapted and evaluated with this population. Intensive psychoeducation may improve knowledge and decision-making which could potentially translate to reductions in HIV risk behaviors. A peer group randomized controlled comparison of an adapted EBI vs. control was delivered over an eight-day summer basketball camp in one reservation-based tribal community to adolescents ages 13–19. Outcome data were gathered immediately post-camp and at 6 and 12 months follow-up. Self-selected peer groups were randomized to intervention (n = 138) or control (n = 129) conditions for a total sample of 267 participants (56.2% female), mean age 15.1 years (SD = 1.7). Intervention participants had better condom use self-efficacy post-camp (Adjusted Mean Difference [AMD] = ?0.75, p < 0.005) and at 6 (AMD = ?0.44, p < 0.005) and 12 months (AMD = ?0.23, p < 0.05) follow-up. Intervention participants also had higher HIV prevention and transmission knowledge (post-camp: AMD = 0.07, p < 0.01; 6 months: AMD = 0.06, p < 0.01) were more likely to believe condoms prevent sexually transmitted infections (post-camp: RR = 1.41, p < 0.005; 6 months: RR = 1.34, p < 0.05), to talk with an adult about HIV/AIDS (post-camp: RR=1.78, p < 0.005; 6 months: RR = 1.14, p < 0.005), had higher partner negotiation efficacy related to substance use during sex (post-camp: AMD = 0.37, p < 0.01), and were more likely to intend to use a condom (post-camp: RR = 1.39, p < 0.01). The adapted intervention had short- and medium-term impacts on AI adolescent risk for HIV/AIDS, but attenuated at 12 months. Intervention delivery through a community-based camp is feasible and acceptable with strong retention. Additional study is needed to evaluate the adapted intervention's impact on sexual risk behaviors and if booster sessions and parent involvement translate to long-term impacts. 相似文献
2.
Interprofessional collaboration and communication in nursing homes: a qualitative exploration of problems in medical care for nursing home residents – study protocol
下载免费PDF全文
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
3.
Low myocardial glucose uptake in Turner syndrome is unaffected by growth hormone: a randomized,placebo‐controlled FDG‐PET study
下载免费PDF全文
![点击此处可从《Clinical endocrinology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
4.
L. Bennet A. Halling J. Berglund 《European journal of clinical microbiology & infectious diseases》2006,25(7):426-432
The aim of the present study was to investigate the long-term incidence rate of Lyme borreliosis and, additionally, to determine whether a correlation exists between climatic factors and summer-season variations in the incidence of Lyme borreliosis. Climatic variability acts directly on tick population dynamics and indirectly on human exposure to Lyme borreliosis spirochetes. In this study, conducted in primary healthcare clinics in southeastern Sweden, electronic patient records from 1997–2003 were searched for those that fulfilled the criteria for erythema migrans. Using a multilevel Poisson regression model, the influence of various climatic factors on the summer-season variations in the incidence of erythema migrans were studied. The mean annual incidence rate was 464 cases of erythema migrans per 100,000 inhabitants. The incidence was significantly higher in women than in men, 505 and 423 cases per 100,000 inhabitants, respectively (p<0.001). The summer-season variations in the erythema migrans incidence rate correlated with the monthly mean summer temperatures (incidence rate ratio 1.12; p<0.001), the number of winter days with temperatures below 0°C (incidence rate ratio 0.97; p<0.001), the monthly mean summer precipitation (incidence rate ratio 0.92; p<0.05), and the number of summer days with relative humidity above 86% (incidence rate ratio 1.04; p<0.05). In conclusion, Lyme borreliosis is highly endemic in southeastern Sweden. The climate in this area, which is favourable not only for human tick exposure but also for the abundance of host-seeking ticks, influences the summer-season variations in the incidence of Lyme borreliosis. 相似文献
5.
Kerstin Schmidt Johannes Hoffend Annette Altmann Ludwig G Strauss Antonia Dimitrakopoulou-Strauss Britta Engelhardt Dirk Koczan J?rg Peter Thomas J Dengler Walter Mier Michael Eisenhut Uwe Haberkorn Ralf Kinscherf 《Journal of nuclear medicine》2006,47(3):543-551
Growth of malignant tumors is dependent on sufficient blood supply. Thus, inhibition of tumor angiogenesis is emerging as a promising target in the treatment of malignancies. Human angiostatin (hANG) is one of the most potent inhibitors of endothelial cell proliferation, angiogenesis, and tumor growth in vivo. However, its mechanisms operating in vivo are not well understood. METHODS: To obtain more information about functional changes in the angiogenic process, we established Morris hepatoma (MH3924A) cell lines expressing hANG (hANG-MH3924A). The effects of hANG expression on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) were measured in coculture experiments in vitro. To evaluate changes in tumor perfusion and blood volume, H2 15O and 68Ga-DOTA-albumin (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid) were used for PET studies in vivo. Additionally, immunohistologic quantification of vascularization, apoptosis, and proliferation as well as gene array analyses were performed. RESULTS: Our in vitro experiments demonstrate reduced proliferation and increased apoptosis in HUVECs when being cocultured with hANG-MH3924A. In support, tumor growth of hANG-MH3924A is diminished by 95% in vivo. However, tumor perfusion and blood volume are increased in hANG-MH3924A corresponding to an increased microvessel density. Furthermore, hANG-transfected tumors show changes in expression of genes related to apoptosis, stress, signal transduction, and metabolism. CONCLUSION: hANG expression leads to inhibition of tumor growth, increased apoptosis, and changes in the expression of multiple genes involved in stress reactions, signal transduction, and apoptosis, which indicates a multifactorial reaction of tumors. An enhanced microvessel density is seen as part of these reactions and is associated with increased perfusion as measured by PET. 相似文献
6.
Long-term results of above knee femoro-popliteal bypass depend on indication for surgery and graft-material. 总被引:3,自引:0,他引:3
J Berglund M Bj?rck J Elfstr?m 《European journal of vascular and endovascular surgery》2005,29(4):412-418
OBJECTIVE To determine the long-term results of above-knee femoro-popliteal bypass with autologous saphenous vein (SV) or expanded polytetrafluoroethylene (ePTFE) in routine surgical practice. METHODS: Data from the Swedish vascular registry, Swedvasc, was reviewed retrospectively. Patients with bypass surgery in 1996 and 1997 were assessed 5-7 years later. Data were gathered from the case-records and from clinical follow-up. The composite endpoint of graft failure included death within 30 days, occlusion, major amputation, extension of the graft to below-knee position and removal of an infected graft. Kaplan-Meier curves and Cox' proportional hazard ratios were calculated. RESULTS: Four hundred and ninety-nine patients undergoing bypass for critical limb ischemia (CLI) (56%) or claudication (44%), SV (28%) or ePTFE (72%), were included. There were no significant differences in patient characteristics between patients with SV or ePTFE. CLI and ePTFE were risk factors for graft failure. For patients with both claudication and CLI SV grafts yielded better long-term results than ePTFE grafts ( p <0.03) and ( p <0.003), respectively. Symptom aggravation after graft occlusion was almost exclusively restricted to ePTFE grafts. CONCLUSIONS: Femoro-popliteal bypass above-knee with SV gives good long-term results, especially for claudication. ePTFE grafts cannot be recommended in claudicants, since occlusion occurs often and frequently leads to CLI. 相似文献
7.
Mark L. Laudenslager Maria L. Boccia Christy L. Berger Mary M. Gennaro-Ruggles Britta McFerran Martin L. Reite 《Developmental psychobiology》1995,28(4):199-211
Many behavioral, immunological, and physiological consequences of brief maternal separation in bonnet (Macaca radiata) and pigtail monkeys (Macaca nemistrina) have been documented. However, the impact of social separation on plasma cortisol and growth hormone is unknown for these particular species. In the present study, the behavioral and endocrinological consequences of a 2-week maternal separation in socially housed infant bonnet and pigtail monkeys were followed. In seven pairs (separated and matched control) of bonnet and six pairs of pigtail infants, plasma was obtained under baseline, separated, and reunion conditions twice weekly for the duration of the study. Blood samples were obtained from both infants of the pair in approximately 10 min. Plasma total cortisol, free cortisol, and growth hormone were measured in these samples. Focal animal behavioral observations were made on all subjects twice daily throughout the study period. In both species, total cortisol and free cortisol rose immediately following maternal separation in comparison to the matched nonseparated controls and returned to basal levels (e.g., that of matched non-separted controls) following reunion with the mother. In contrast, plasma growth hormone rose only in the pigtail infants over a time course that peaked around the time of reunion. Multiple regression techniques indicated for the first week of separation, in the separated but not control subjects, that mean plasma free and total cortisol was positively related to distress behaviors (vocalization and postural slouch) observed during this week and negatively related to social behaviors (play and proximity to others) noted during the same period. In contrast, plasma growth hormone was related to both species and sex of the subjects but unrelated to behavioral variables. © 1995 John Wiley & Sons, Inc. 相似文献
8.
Influence of age on faecal carriage of P-fimbriated Escherichia coli and other gram-negative bacteria in hospitalized neonates 总被引:3,自引:0,他引:3
K. Tullus B. Fryklund B. Berglund G. Kllenius L. G. Burman 《The Journal of hospital infection》1988,11(4):349-356
The aerobic faecal flora of 953 infants aged over 5 days was studied on discharge from 22 neonatal wards in Swedish hospitals. Klebsiella/enterobacter was isolated from 74% of infants and dominated the aerobic gram-negative flora in 19 wards. Escherichia coli was carried by 42% and showed a slight dominance in two wards. Initially klebsiella/enterobacter dominated the flora but became increasingly mixed with and taken over by E. coli, carriage increasing from 21% in infants discharged after 5-7 days to 57% after 3 weeks or later. Among infants with E. coli, P-fimbriated strains were demonstrated in 23% (range 0-67) and were independent of age. Occasional clustering of such strains was observed in 3/22 wards during the study period. It is postulated that the general and local colonization patterns observed reflect differences between individual strains of E. coli and klebsiella in both their capacity for transmission and their persistence in the newborn gut. The role of P-fimbriae in intestinal colonization of neonates by E. coli was, however, not supported. 相似文献
9.
Peter Wallstr?m Krystyna Frenkel Elisabet Wirf?lt Bo Gullberg Jerzy Karkoszka Janeric Seideg?rd Lars Janzon G?ran Berglund 《Cancer epidemiology, biomarkers & prevention》2003,12(5):444-451
Plasma autoantibodies (aAbs) against the oxidized DNA base derivative 5-hydroxymethyl-2'-deoxyuridine (5-HMdU) are potential biomarkers of cancer risk and oxidative stress. We examined their association with a number of cancer risk factors: smoking, alcohol habits, body fatness, and absence of the glutathione S-transferases M1 and T1 (GSTM1 and GSTT1) in a sample from the population-based Malm? Diet and Cancer cohort (Sweden). This was a cross-sectional study of 264 men and 280 women, 46-67 years of age. Anti-5-HMdU aAb concentration was determined by an ELISA. Data on tobacco exposure were collected through a questionnaire. Alcohol consumption was estimated by a modified diet history method. Body fatness was assessed by a bioimpedance method. The absence or presence of genes coding for GSTM1 and GSTT1 was determined in granulocyte DNA by a multiplex PCR technique. aAb titers were significantly greater in those with high alcohol consumption. Current smokers lacking GSTM1, particularly men, had greater aAb titers compared with nonsmokers or persons expressing GSTM1. Body fatness was inversely associated with antibody titers in men. GSTT1 genotype was not associated with aAb titers. Overall, women had higher aAb titers than men. Adjustment for potential confounders (history of chronic diseases, anti-inflammatory medication, and season of blood sampling) did not change the results. Our study shows that a high alcohol consumption, smoking in combination with lack of GSTM1, and low body fatness (in men) is associated with high titers of anti-5-HMdU aAbs in this population. 相似文献
10.