全文获取类型
收费全文 | 4324篇 |
免费 | 306篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 154篇 |
妇产科学 | 73篇 |
基础医学 | 662篇 |
口腔科学 | 211篇 |
临床医学 | 385篇 |
内科学 | 888篇 |
皮肤病学 | 112篇 |
神经病学 | 475篇 |
特种医学 | 84篇 |
外科学 | 444篇 |
综合类 | 30篇 |
一般理论 | 1篇 |
预防医学 | 328篇 |
眼科学 | 39篇 |
药学 | 386篇 |
中国医学 | 1篇 |
肿瘤学 | 319篇 |
出版年
2021年 | 60篇 |
2020年 | 52篇 |
2019年 | 51篇 |
2018年 | 65篇 |
2017年 | 47篇 |
2016年 | 61篇 |
2015年 | 51篇 |
2014年 | 71篇 |
2013年 | 138篇 |
2012年 | 201篇 |
2011年 | 190篇 |
2010年 | 101篇 |
2009年 | 97篇 |
2008年 | 211篇 |
2007年 | 195篇 |
2006年 | 219篇 |
2005年 | 202篇 |
2004年 | 199篇 |
2003年 | 182篇 |
2002年 | 176篇 |
2001年 | 161篇 |
2000年 | 139篇 |
1999年 | 126篇 |
1998年 | 59篇 |
1997年 | 53篇 |
1996年 | 42篇 |
1995年 | 40篇 |
1994年 | 36篇 |
1993年 | 41篇 |
1992年 | 131篇 |
1991年 | 116篇 |
1990年 | 98篇 |
1989年 | 113篇 |
1988年 | 71篇 |
1987年 | 81篇 |
1986年 | 84篇 |
1985年 | 97篇 |
1984年 | 65篇 |
1983年 | 54篇 |
1982年 | 42篇 |
1981年 | 27篇 |
1980年 | 25篇 |
1979年 | 33篇 |
1978年 | 37篇 |
1977年 | 30篇 |
1975年 | 26篇 |
1974年 | 31篇 |
1973年 | 20篇 |
1972年 | 27篇 |
1971年 | 19篇 |
排序方式: 共有4649条查询结果,搜索用时 15 毫秒
81.
Peer K. Lilleng Odd R. Monge Anders Wall e Clement S. Trovik Markus Hordvik Johan H ie Olav Dahl Gisle Bang 《Acta oncologica (Stockholm, Sweden)》1997,36(4):438-440
Fibrosarcoma is a rare tumour in children. The potential of malignancy has been questioned. We present three cases of fibrosarcoma in children. The follow-up periods range from 10 to 37 years. The first patient had pulmonary metastases at the time of diagnosis in 1958. The primary tumour in fossa ischio-rectalis was resected in 1960. Lung metastases were resected in 1960 and 1989. Radiotherapy was given in 1992. He is still alive with metastases 37 years after the first manifestation of disease. The second patient had a primary tumour and several local recurrences in the mandible. He is alive without evidence of disease 4 years after resection of pulmonary metastases and 21 years after resection of the primary tumour. The third patient has no signs of recurrence or metastasic spread 10 years after a wide excision of subcutanous tumours of the left upper arm. The cases demonstrate a special tumour-entity of low-grade malignancy, which show a good prognosis and a wide spectrum of biological behaviour. 相似文献
82.
Although effective in neuropathic pain, the efficacy of systemic lidocaine in non-neuropathic pain remains uncertain. We investigated the analgesic effect of systemic lidocaine on the heat/capsaicin sensitization model of experimental pain in 24 volunteers. Sensitization was produced by heating the skin to 45 degrees C for 5 min, followed by a 30-min application of 0.075% capsaicin cream, and maintained by periodically reheating the sensitized skin. Subjects received IV lidocaine (bolus 2 mg/kg, then infusion 3 mg. kg. h), or saline for 85 min. Areas of secondary hyperalgesia, heat pain detection thresholds, and painfulness of stimulation with 45 degrees C for 1 min (long thermal stimulation) were quantified. Systemic lidocaine reduced the area of secondary hyperalgesia to brush, but not to von Frey hair stimulation. Lidocaine did not alter heat pain detection thresholds or painfulness of long thermal stimulation in normal skin. We conclude that, at infusion rates in the low- to mid-antiarrhythmic range, lidocaine has no effect on acute nociceptive pain but does have a limited and selective effect on secondary hyperalgesia. Implications: The efficacy of systemic lidocaine in nonneuropathic pain remains uncertain. This study investigates the effect of systemic lidocaine on experimental-induced hyperalgesia in 25 volunteers. Hyperalgesia was induced by using an experimental pain model that uses heat and capsaicin in combination. Systemic lidocaine showed a selective effect on secondary hyperalgesia. 相似文献
83.
Tovi Lehmann Douglas H Graham Erica R Dahl Lilian M G Bahia-Oliveira S M Gennari J P Dubey 《Infection, genetics and evolution》2004,4(2):107-114
Previous studies of Toxoplasma gondii, based on samples dominated by clinical isolates, have concluded that its population structure is clonal, despite the sexual reproduction that occurs in cats. To determine whether this applies to non-clinical isolates, we compared patterns of linkage disequilibrium (LD) among seven loci in samples of T. gondii from Brazil and the US. LD was detected in both locations, but it was substantially lower in Brazil. The lower LD in Brazil can be explained by a higher rate of sexual reproduction between different genotypes (outcrossing) because of a higher rate of transmission. The extent of LD between pairs of physically unlinked loci varied significantly in each location. Moreover, the magnitude of LD between corresponding locus pairs in Brazil and the US was correlated, despite minimal gene exchange between the continents (mean FST = 0.19). The heterogeneity among locus pairs and the correlation in LD between physically unlinked locus pairs from different continents suggests that locus-specific factors, such as epistatic selection are involved in maintaining LD in T. gondii. Possibly, the unique life cycle of T. gondii with its unpredictable transmission among diverse host species and distinct ecological habitats requires specific combinations of alleles from multiple loci. The usefulness of typing isolates based on physically unlinked loci is questioned not only by the geographic variation in the reproductive population structure, but mainly by the low overall predictability of the genotype of one locus based on the genotype in another (unlinked) locus. This predictability ranged between 23 and 45%, but was close to nil for a considerable fraction of locus pairs. 相似文献
84.
Lene Thorsen Eva Skovlund Sigmund B Str?mme Kjersti Hornslien Alv A Dahl Sophie D Foss? 《Journal of clinical oncology》2005,23(10):2378-2388
PURPOSE: To evaluate the effectiveness of a supervised home-based flexible training program on cardiorespiratory fitness (CRF), mental distress, and health-related quality of life (HRQOL) parameters in young and middle-aged cancer patients shortly after curative chemotherapy. PATIENTS AND METHODS: One hundred eleven patients age 18 to 50 years who had received chemotherapy for lymphomas or breast, gynecologic, or testicular cancer completed the trial. These patients were randomly allocated to either an intervention group (n = 59), which underwent a 14-week training program, or a control group (n = 52) that received standard care. Primary outcome was change in CRF, as determined by Astrand-Rhyming indirect bicycle ergometer test (maximum oxygen uptake [VO(2max)]), between baseline (T0) and follow-up (T1). Secondary outcomes were mental distress, as assessed by the Hospital Anxiety and Depression Scale, and HRQOL, as assessed by the European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire. Two-way analysis of covariance was used to analyze changes from T0 to T1. RESULTS: VO(2max) increased by 6.4 mL/kg(-1)/min(-1) in patients in the intervention group and by 3.1 mL/kg(-1)/min(-1) in patients in the control group (P < .01). The fatigue score decreased by 17.0 points in the control group compared with only 5.8 points in the intervention group (P < .01). There were no intergroup differences in mental distress or HRQOL. CONCLUSION: A supervised, home-based, flexible training program has significant effect on CRF in young and middle-aged cancer patients shortly after curative chemotherapy, but it has no favorable effect on patients' experience of fatigue, mental distress, or HRQOL. 相似文献
85.
Ludvig Paul Muren Asa Karlsdottir Yngve Kvinnsland Tore Wentzel-Larsen Olav Dahl 《Radiotherapy and oncology》2005,75(3):293-302
BACKGROUND AND PURPOSE: To study the impact of the new ICRU 62 'Planning organ at Risk Volume' (PRV) concept on the relationship between rectum dose-volume histogram (DVH) data and toxicity. PATIENTS AND METHODS: The acute gastro-intestinal (GI) RTOG toxicity in 127 prostate cancer patients prescribed a total dose of 70 Gy with conformal irradiation to either the prostate, the prostate and seminal vesicles or the whole pelvis (initial 50 Gy only) were analysed. DVHs were derived for the rectum only and for rectum extended with six PRV margin sets (narrow/intermediate/wide; anterior/anterior and posterior). The data was analysed using permutation tests, logistic regression and effective uniform dose (EUD) calculations. RESULTS: Acute Grade 2 GI toxicity was seen in 22 of 127 cases (17%). Permutation tests showed that the difference between DVHs for patients with and without Grade 2 effects was significant, both for rectum only and rectum PRVs (P-value range: 0.02-0.04), with generally lower P-values for the PRVs. In the logistic regression, the fractional DVH variables (i.e. volumes) were significantly related to toxicity, with approximately 2-3 times as many significant dose levels for the PRVs as for rectum only. E.g. with wide anterior and posterior margins (16 and 11 mm, respectively) the relation was significant at 26 different dose levels (6-7, 13-14, 35-43, 60-71 and 73 Gy), compared to nine levels (38-40, 43-44 and 71-74 Gy) for rectum only. EUDs were significantly different for patients with and without Grade 2 effects both for rectum only and the PRVs (95% confidence interval for EUD increase with Grade 2 effects: 0.1-3.1 Gy). CONCLUSIONS: All statistical methods applied indicated a small, but definite difference in DVH parameters between patients with versus those without Grade 2 effects. The difference was most pronounced when margins of 16 mm anterior and 11 mm posterior were applied. 相似文献
86.
Poll LW Koch JA vom Dahl S Sarbia M Niederau C Häussinger D Mödder U 《Skeletal radiology》2000,29(1):15-21
Objective. To investigate the frequency and morphology of extraosseous extension in patients with Gaucher disease type I.
Design and patients. MRI examinations of the lower extremities were analyzed in 70 patients with Gaucher disease type I. Additionally, the thoracic
spine and the midface were investigated on MRI in two patients.
Results. Four cases are presented in which patients with Gaucher disease type I and severe skeletal involvement developed destruction
or protrusion of the cortex with extraosseous extension into soft tissues. In one patient, Gaucher cell deposits destroyed
the cortex of the mandible and extended into the masseter muscle. In the second patient, multiple paravertebral masses with
localized destruction of the cortex were apparent in the thoracic spine. In the third and fourth patient, cortical destruction
with extraosseous tissue extending into soft tissues was seen in the lower limbs.
Conclusions. Extraosseous extension is a rare manifestation of Gaucher bone disease. While an increased risk of cancer, especially hematopoietic
in origin, is known in patients with Gaucher disease, these extraosseous benign manifestations that may mimic malignant processes
should be considered in the differential diagnosis of extraosseous extension into soft tissues. A narrow neck of tissue was
apparent in all cases connecting bone and extraosseous extensions.
Received: 19 July 1999 Revision requested: 8 September 1999 Revision received: 7 October 1999 Accepted: 14 October 1999 相似文献
87.
88.
89.
90.