全文获取类型
收费全文 | 15385篇 |
免费 | 804篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 128篇 |
儿科学 | 296篇 |
妇产科学 | 473篇 |
基础医学 | 1838篇 |
口腔科学 | 555篇 |
临床医学 | 1238篇 |
内科学 | 4364篇 |
皮肤病学 | 383篇 |
神经病学 | 1385篇 |
特种医学 | 318篇 |
外科学 | 2240篇 |
综合类 | 97篇 |
一般理论 | 2篇 |
预防医学 | 1119篇 |
眼科学 | 219篇 |
药学 | 812篇 |
中国医学 | 73篇 |
肿瘤学 | 721篇 |
出版年
2024年 | 14篇 |
2023年 | 154篇 |
2022年 | 380篇 |
2021年 | 638篇 |
2020年 | 341篇 |
2019年 | 526篇 |
2018年 | 688篇 |
2017年 | 400篇 |
2016年 | 415篇 |
2015年 | 471篇 |
2014年 | 711篇 |
2013年 | 829篇 |
2012年 | 1296篇 |
2011年 | 1310篇 |
2010年 | 665篇 |
2009年 | 605篇 |
2008年 | 1031篇 |
2007年 | 948篇 |
2006年 | 911篇 |
2005年 | 870篇 |
2004年 | 770篇 |
2003年 | 610篇 |
2002年 | 612篇 |
2001年 | 73篇 |
2000年 | 75篇 |
1999年 | 84篇 |
1998年 | 94篇 |
1997年 | 63篇 |
1996年 | 73篇 |
1995年 | 61篇 |
1994年 | 47篇 |
1993年 | 35篇 |
1992年 | 45篇 |
1991年 | 28篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 14篇 |
1986年 | 27篇 |
1985年 | 19篇 |
1984年 | 26篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1974年 | 12篇 |
1973年 | 19篇 |
1972年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Joanna Izewska Pedro Andreo Stanislav Vatnitsky Ken R Shortt 《Radiotherapy and oncology》2003,69(1):91-97
BACKGROUND AND PURPOSE: The IAEA/WHO TLD postal programme for external audits of the calibration of high-energy photon beams used in radiotherapy has been in operation since 1969. This work presents a survey of the 1317 TLD audits carried out during 1998-2001. The TLD results are discussed from the perspective of the dosimetry practices in hospitals in developing countries, based on the information provided by the participants in their TLD data sheets. MATERIALS AND METHODS: A detailed analysis of the TLD data sheets is systematically performed at the IAEA. It helps to trace the source of any discrepancy between the TLD measured dose and the user stated dose, and also provides information on equipment, dosimetry procedures and the use of codes of practice in the countries participating in the IAEA/WHO TLD audits. RESULT: The TLD results are within the 5% acceptance limit for 84% of the participants. The results for accelerator beams are typically better than for Co-60 units. Approximately 75% of participants reported dosimetry data, including details on their procedure for dose determination from ionisation chamber measurements. For the remaining 25% of hospitals, who did not submit these data, the results are poorer than the global TLD results. Most hospitals have Farmer type ionisation chambers calibrated in terms of air kerma by a standards laboratory. Less than 10% of the hospitals use new codes of practice based on standards of absorbed dose to water. CONCLUSION: Despite the differences in dosimetry equipment, traceability to different standards laboratories and uncertainties arising from the use of various dosimetry codes of practice, the determination of absorbed dose to water for photon beams typically agrees within 2% among hospitals. Correct implementation of any of the dosimetry protocols should ensure that significant errors in dosimetry are avoided. 相似文献
72.
Adjuvant immunization of HLA-A2-positive melanoma patients with a modified gp100 peptide induces peptide-specific CD8+ T-cell responses. 总被引:3,自引:0,他引:3
John W Smith Edwin B Walker Bernard A Fox Daniel Haley Ketura P Wisner Teri Doran Brenda Fisher Lisa Justice William Wood John Vetto Holden Maecker Annemiek Dols Sybren Meijer Hong-Ming Hu Pedro Romero W Gregory Alvord Walter J Urba 《Journal of clinical oncology》2003,21(8):1562-1573
PURPOSE: To measure the CD8+ T-cell response to a melanoma peptide vaccine and to compare an every-2-weeks with an every-3-weeks vaccination schedule. PATIENTS AND METHODS: Thirty HLA-A2-positive patients with resected stage I to III melanoma were randomly assigned to receive vaccinations every 2 weeks (13 vaccines) or every 3 weeks (nine vaccines) for 6 months. The synthetic, modified gp100 peptide, g209-2M, and a control peptide, HPV16 E7, were mixed in incomplete Freund's adjuvant and injected subcutaneously. Peripheral blood mononuclear cells obtained before and after vaccination by leukapheresis were analyzed using a fluorescence-based HLA/peptide-tetramer binding assay and cytokine flow cytometry. RESULTS: Vaccination induced an increase in peptide-specific T cells in 28 of 29 patients. The median frequency of CD8+ T cells specific for the g209-2M peptide increased markedly from 0.02% before to 0.34% after vaccination (P <.0001). Eight patients (28%) exhibited peptide-specific CD8+ T-cell frequencies greater than 1%, including two patients with frequencies of 4.96% and 8.86%, respectively. Interferon alfa-2b-treated patients also had significant increases in tetramer-binding cells (P <.0001). No difference was observed between the every-2-weeks and the every-3-weeks vaccination schedules (P =.59). CONCLUSION: Flow cytometric analysis of HLA/peptide-tetramer binding cells was a reliable means of quantifying the CD8+ T-cell response to peptide immunization. This assay may be suitable for use in future trials to optimize different vaccination strategies. Concurrent interferon treatment did not inhibit the development of a peptide-specific immune response and vaccination every 2 weeks, and every 3 weeks produced similar results. 相似文献
73.
Angel Asensio Antonio Ramos Elena Mú?ez José L Vilanova Pedro Torrijos Fernando J García 《Infection control and hospital epidemiology》2005,26(12):903-909
OBJECTIVE: To investigate the effect of preoperative initiation of low molecular weight heparin as prophylaxis for deep venous thrombosis in patients at risk of developing surgical-site infections after knee arthroplasty. DESIGN: Case-control study nested in a cohort. The incidence of surgical-site infection in the cohort was calculated. With the use of data extracted from medical histories and after adjustment for other risk factors, the effect of preoperative heparinization on the risk of incisional and prosthetic infection among case-patients and control-patients (1:3 ratio) was assessed. SETTING: Orthopedic department in a tertiary-care referral hospital. PATIENTS: A cohort of 160 consecutive patients who had received prosthetic knee implants between October 1, 2001, and November 30, 2003. RESULTS: Eighteen patients with surgical-site infections were identified, yielding an incidence of incisional and prosthetic infection of 6.9 (95% confidence interval [CI95], 3.5 to 12.0) and 4.4 (CI95, 1.8 to 8.8) cases per 100 patients undergoing surgery, respectively. Surgical-site infection was associated with preoperative use of low molecular weight heparin (odds ratio [OR], 6.2 after adjustment for medical and surgical factors; CI95 1.5 to 23). Prosthetic infection was strongly associated with preoperative use of prophylaxis (OR, undetermined [100% exposure in case-patients vs 35% exposure in control-patients]; P = .002), but incisional surgical-site infection was not. CONCLUSION: The use of low molecular weight heparins immediately before knee arthroplasty as prophylaxis for deep venous thrombosis should be questioned because of probable increased risk of prosthetic infection. 相似文献
74.
Changes in the Household Calorie Supply during the 1994 Economic Crisis in Mexico and Its Implications on the Obesity Epidemic 总被引:2,自引:0,他引:2
Pedro Arroyo M.D. M.P.H. M.Sc. Alvar Loria Ph.g. Oscar Méndez B.S. 《Nutrition reviews》2004,62(S2):S163-S168
To characterize the effects of the 1994 economic crisis on calorie sources of Mexican households, five nutrition surveys done every leap year (1992–2000) in national representative samples (> 10,000 households) were analyzed. Each household was visited during 7 days to collect data on foods purchased, exchanged or home-grown and their monetary value. We selected 88 food items to calculate kilocalories/ person/day and cost in pesos/megacalorie (CPMC) for rural-urban strata (localities <2500, ≥2500). The food items were classified in 8 groups and the summation of kilocalories and CPMCs of items in each group were our units of analysis. Linear regressions for 1992–2000 were performed, and slopes and intercepts were used to characterize changes. Available calories showed very little change at the height of the economic crisis. Expensive calories (meat in ur-bans, eggs and milk in rurals, and industrialized meat and soft drinks in both) tended to increase, whereas the most inexpensive staples (cereals, legumes, sugars) decreased their share in both strata. An increase in obesigenic calories was seen, notably in soft drinks, despite a cost increase second only to meat. Main conclusions were: (1) the economic crisis did not affect total calories availability in Mexican households; (2) the 1992–2000 trends in calorie sources were contrary to any crisis effect in rurals and urbans (i.e., expensive foods increased and inexpensive staples decreased); (3) there were sizable rural-urban differences in number, source, and cost of calories; and (4) obesigenic calories increased and soft drinks emerged as a food with its own dynamic. 相似文献
75.
Pedro Cabral 《European journal of paediatric neurology》2006,10(2):66-77
Attention deficit disorder (AAD) and attention deficit/hyperactivity disorder (ADHD) are very frequent and protean developmental disorders without a definite biologic marker. This review proposes a framework to understand the enlarged spectrum of its manifestations based on current knowledge of the mechanisms underlying arousal and attention variations during sleep/wake cycle. The neuro-modulation's pivotal role in this process as well as in the fine tuning of synaptic architecture during development must be taken into account when trying to understand the marked fuzziness of the symptoms and the very high prevalence of reported co-morbidities. The series of related interactions includes a cyclic deactivation of the dorso-lateral portion of the prefrontal cortex (DLPFC) during sleep, suspending executive functions, co-occurring with rhythmic periods of decreased noradrenergic tonus. A protracted unbalance in modulation, with catecholaminergic relative deficiency, could explain less-than-optimum waking DLPFC activation and the most important manifestations of ADD. Beside the well documented dopaminergic effects of stimulant medication used in ADD and ADHD, a more important role must be assigned to noradrenaline (NA). At this light hyperactivity and impulsivity are less important dimensions. Rather, an attention deficit spectrum disorder should probably be regarded as a complication of a core defect in prefrontal cortex dependent inhibitory control, underlying inattention. 相似文献
76.
Isabel Monteiro-Grillo Pedro Marques-Vidal Marília Jorge 《Clinical & translational oncology》2005,7(11):499-503
Purpose To compare the quality-of-life (QoL) and psycho-social changes in a group of patients with early breast cancer who underwent
conservative surgery (BCS) or modified radical mastectomy (MRM).
Methods Self-administered questionnaire assessing body image perception, social habits, sexual attraction and self-consciousness with
relatives/friends, was randomly assigned to 125 patients (61 BCS, 64 MRM; aged 53±8 and 50±9 years, respectively, p=NS).
Results MRM patients reported a significantly higher frequency of changes in body image perception and other related social behaviour
such as avoiding going to the beach or using low-cut clothes, and reticence with friends. Conversely, no differences were
found regarding sexuality, denial of the disease by the husband/partner, or concealing the disease from family members. Also,
no significant differences were found between patients above and below the age of 50 years, for all variables studied after
adjustment for surgical procedure.
Conclusions Modified radical mastectomy has a negative effect on body image perception and in social behaviour patterns of patients and
with a concomitant decrease in QoL. The sexuality of the patient is not significantly affected. 相似文献
77.
Pedro Kringen Yun Wang Vanessa Dumeaux Jahn M Nesland Gunnar Kristensen Anne-Lise Borresen-Dale Anne Dorum 《BMC cancer》2005,5(1):134
Background
Ovarian carcinomas from 30 BRCA1 germ-line carriers of two distinct high penetrant founder mutations, 20 carrying the 1675delA and 10 the 1135insA, and 100 sporadic cases were characterized for somatic mutations in the TP53 gene. We analyzed differences in relation to BRCA1 germline status, TP53 status, survival and age at diagnosis, as previous studies have not been conclusive. 相似文献78.
Filipa Alves da Costa Jos Pedro Guerreiro Magda Nunes de Melo Ana da Costa Miranda Ana Paula Martins Jos Garo Brenda Madureira 《The International journal of pharmacy practice》2005,13(3):205-211
Objective Poor compliance to antihypertensive medications has been identified as a primary cause of uncontrolled blood pressure (BP), with consequent increases in hypertension‐related morbidity and mortality. Therefore, any measure known to improve compliance should be encouraged. This study assessed the impact of reminder cards on compliance to antihypertensive therapy. Method A field trial was undertaken in pharmacies located in the districts of Lisbon and Porto. Eligible participants comprised those aged 30–74 years, prescribed an angiotensin‐converting enzyme inhibitor (ACEI) in monotherapy, and taken on a once‐daily regimen. Patients were allocated to control group (CG) or intervention group (IG), the latter being provided with a reminder card, an alarm‐type device due to remind the patient of the time to take his medication. Patients were monitored monthly during 3 months for compliance and blood pressure control. Key findings Seventy‐one patients participated in the study (intervention: 35; control group: 36). Compliance was similar between the groups in the first 2 months of follow‐up (97.1% IG vs 94.9% CG at first follow‐up and 97.5% IG vs 94.2% CG at second follow‐up) and higher in the intervention group at the end of the study (97.3% IG vs 87.3% CG; P = 0.011). There were no mean blood pressure differences between compliant and non‐compliant subjects at the end of the study (P value for differences in systolic BP (Psyst) = 0.580; and P value for differences in diastolic BP (Pdlast) = 0.175). Conclusion This small‐scale study indicates a possible positive impact on patients' compliance resulting from the use of reminder cards. However, this needs confirming in larger scale studies with longer monitoring periods. 相似文献
79.
Ignacio Ruiz del Olmo Izuzquiza Matilde Bustillo Alonso María Luisa Monforte Cirac Pedro Burgués Prades Carmelo Guerrero Laleona 《Anales de pediatría (Barcelona, Spain : 2003)》2017,86(3):115-121
Objective
To study the epidemiology, clinical features, diagnosis, therapeutic management, and outcome of non-tuberculous mycobacterial lymphadenitis in a paediatric population of Aragón (Spain).Material and methods
A retrospective study was conducted on patients under 15 years-old diagnosed with non-tuberculous mycobacterial lymphadenitis between the years 2000 and 2015. Inclusion criteria: patients with lymphadenitis and positive culture. Quantitative values are shown as mean, rank, and standard deviation, and qualitative data as frequencies.Results
Twenty-seven cases were registered, with a mean age of presentation of 39.9 months (range 10 months–8 years). The mean time between the symptoms onset and first consultation was 1.7 ± 1.1 months. The most frequent location was sub-maxilar in 17/27 cases (63%), on the right side in 59.3%, and size 2.96 ± 1.26 cm. Fistulae were observed in 16/27 cases. Tuberculin test was greater than 10 mm in 7/24 (29.1%). Microbiological cultures were positive for Mycobacterium avium in 14/27 (51.9%), Mycobacterium intracellulare 3/27 (11.1%), and Mycobacterium lentiflavum 3/27 (11.1%). Combined treatment of antibiotics and surgery was given in 16/27 cases (59.8%), medical treatment only in7/27 (25.9%), and surgical exeresis alone in 4/27 (14.8%). Two patients required a new surgery, and one showed severe neutropenia secondary to rifabutin. Only one case (3.7%) suffered from temporary facial palsy as sequel.Conclusions
The most frequent treatment was the combination of antibiotics and surgery. Delay in diagnosis seemed to be responsible for the limited number of exeresis as first option, only one for every seven patients. 相似文献80.