全文获取类型
收费全文 | 3989篇 |
免费 | 166篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 77篇 |
妇产科学 | 65篇 |
基础医学 | 468篇 |
口腔科学 | 425篇 |
临床医学 | 259篇 |
内科学 | 1107篇 |
皮肤病学 | 64篇 |
神经病学 | 297篇 |
特种医学 | 97篇 |
外科学 | 533篇 |
综合类 | 22篇 |
预防医学 | 291篇 |
眼科学 | 43篇 |
药学 | 254篇 |
中国医学 | 22篇 |
肿瘤学 | 112篇 |
出版年
2023年 | 35篇 |
2022年 | 94篇 |
2021年 | 176篇 |
2020年 | 82篇 |
2019年 | 126篇 |
2018年 | 167篇 |
2017年 | 96篇 |
2016年 | 112篇 |
2015年 | 148篇 |
2014年 | 174篇 |
2013年 | 215篇 |
2012年 | 326篇 |
2011年 | 342篇 |
2010年 | 188篇 |
2009年 | 140篇 |
2008年 | 232篇 |
2007年 | 239篇 |
2006年 | 218篇 |
2005年 | 172篇 |
2004年 | 155篇 |
2003年 | 150篇 |
2002年 | 109篇 |
2001年 | 48篇 |
2000年 | 37篇 |
1999年 | 51篇 |
1998年 | 22篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 11篇 |
1994年 | 7篇 |
1992年 | 11篇 |
1991年 | 22篇 |
1990年 | 16篇 |
1989年 | 22篇 |
1988年 | 13篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 16篇 |
1975年 | 20篇 |
1974年 | 6篇 |
1972年 | 9篇 |
1970年 | 6篇 |
排序方式: 共有4177条查询结果,搜索用时 0 毫秒
1.
Milena Soares Santos Guilherme de Sousa Ribeiro Tainara Queiroz Oliveira Renan Cardoso Nery Santos Edilane Gouveia Kátia Salgado Daniele Takahashi Cleuber Fontes Leila Carvalho Campos Mitermayer Galvão Reis Albert Icksang Ko Joice Neves Reis 《International journal of infectious diseases》2009,13(4):456-461
2.
Paula Vanessa Pedron Oltramari Ricardo de Lima Navarro José Fernando Castanha Henriques Rumio Taga Tania Mary Cestari Guilherme Janson José Mauro Granjeiro 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(5):e9-16
OBJECTIVE: The objective of this study was to radiographically quantify bone density and bone height preservation in tooth extraction alveolus filled with xenograft. STUDY DESIGN: The maxillary and mandibular fourth deciduous molars and fourth premolars of 6 minipigs were removed. Randomly, in 3 animals the right side was used as the test side and in the other 3 animals the left side was the test side. Intraoral radiographs were performed to compare the condition at the initial time and 3 months later. Measurements of bone height and bone density were performed using KS300 (Zeiss) software. RESULTS: After 3 months, there was a statistically significant smaller bone height loss for the test group. The test group presented a statistically greater bone density immediately after tooth extraction. However, after 3 months there was no statistically significant difference between the groups. CONCLUSIONS: The results suggest that treatment of postextraction alveolus with xenograft can preserve bone height initially but differences in bone density compared to when no xenograft is used are not sustained. 相似文献
3.
Heloísio de Rezende Leite Guilherme Silvério de Oliveira Hélio Henrique de Araújo Brito 《American journal of orthodontics and dentofacial orthopedics》2005,128(2):241-251
This case report demonstrates how extracting a maxillary deciduous canine affects the eruption path of a labially displaced ectopically erupting permanent canine. A long-term follow-up is presented, and the biologic mechanisms are discussed. 相似文献
4.
5.
Nelson Wolosker Guilherme Yazbek José Ribas Milanez de Campos Paulo Kauffman Augusto Ishy Pedro Puech-Leão 《Clinical autonomic research》2007,17(3):172-176
Background Sympathectomy is the treatment of choice for primary hyperhidrosis. One curious occurrence that is difficult to explain from
an anatomophysiological point of view in cases of video-assisted thoracoscopic sympathectomy (VATS) for the treatment of palmar
hyperhidrosis (PH) is the observed improvement in plantar hyperhidrosis (PLH). Nevertheless, current reports on VATS rarely
describe the effect on PLH or just give superficial data. The aim of this study was to prospectively investigate, how surgery
affects PLH in patients with PH and PLH over one-year period.
Methods From May 2003 to January 2004, 70 consecutive patients with combined PH and PLH underwent VATS at the T2, T3, or T4 ganglion
level (47 women and 23 men, with mean age of 23 years).
Results Immediately after the operation, all the patients said they were free from PH episodes, except for two patients (2.8%) who
suffered from continued PH. Compensatory hyperhidrosis (CH) of various degrees was observed in 58 (90.6%) patients after one
year. Only 13 (20.3%) suffered from severe CH. There was a great initial improvement in PLH in 50% of the cases, followed
by progressive regression, such that only 23.4% still presented that improvement after one year. The number of cases without
overall improvement increased progressively (from 17.1% to 37.5%) and the numbers with slight improvement remained stable
(32.9–39.1%). Of the 24 patients with no improvement after one year, 6 patients graded plantar sweating worse.
Conclusion Patients with PH and PLH who undergo VATS to treat their PH present a good initial improvement in PLH that reduces to a lower
level of improvement after the one-year period. 相似文献
6.
M Carrara S Zampiron F Capolongo L Cima P Giusti 《European journal of pharmacology》1990,179(3):301-305
The effects of glycine on morphine-induced antinociception were investigated in mice, using a cutaneous thermal test (hot-plate), a visceral chemical test (acetylcholine writhing test), and a locomotor activity test. When glycine (200 mg/kg p.o.) and morphine (5 mg/kg s.c.) were given together during the first 30 min, glycine first antagonized the morphine-induced antinociception then this was followed by a synergistic effect. The two-phase influence of glycine on morphine-induced antinociception may be due to the interaction of glycine with different receptors. 相似文献
7.
T. Stroffolini G. Manzillo R. De Sena E. Manzillo P. Pagliano M. Zaccarelli M. Russo M. Soscia G. Giusti 《European journal of epidemiology》1992,8(4):539-542
Typhoid fever is endemic in the Neapolitan area, where its yearly incidence rate largely exceeds the corresponding national figure. During the period from January to June, 1990, a matched case-control study was carried out in order to identify risk factors of the disease in this area; 51 subjects (mean age 27.2 years) with typhoid fever were compared with 102 controls matched with respect to age, sex and educational level. Consumption of raw shellfish was reported by 76.5% of the cases, as opposed to 19.6% of the controls (P < 0.01). Subjects who had eaten this food item had a 13.3-fold risk (C.I. 95% = 5.5 - 32.8) of contracting typhoid fever. In contrast, no risk was found to be associated with consumption of cooked shellfish, raw vegetables, ice-cream, non-potable water, or unpasteurized milk.The risk factor identified in this study shows that hazardous dietary habits and inadequate sewage treatment facilities, combined with lack of sanitation in the harvesting and marketing of shellfish, play a major role in the endemicity of typhoid fever in the Neapolitan area.Corresponding author. 相似文献
8.
Guilherme Santoro-Lopes Erika Ferraz de Gouvêa Rodrigo Carreira M Monteiro Rodrigo Castelo Branco José Rodolfo Rocco Márcia Halpern Adriana Lúcia Pires Ferreira Elaine Gama Pessoa de Araújo Samanta T Basto Vinicius Gomes Silveira Joaquim Ribeiro-Filho 《Liver transplantation》2005,11(2):203-209
Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infection after orthotopic liver transplantation (OLT). Colonization with MRSA is associated with a higher risk of infection. Previous studies have shown a high prevalence of MRSA colonization among OLT candidates. However, the risk of colonization with MRSA after OLT is still unclear. The objective of this study was to estimate the incidence and the factors associated with colonization with MRSA after OLT. This was a prospective cohort study including patients submitted to OLT between the years 2000 and 2002. Surveillance cultures of nasal swab specimens were performed within the 1st 72 hours of hospital admission and, subsequently, on weeks 2, 6, 13, and 26. Patients whose baseline cultures revealed nasal carriage of MRSA were excluded. A total of 60 patients were included in the study. The median follow-up was 72 days. A total of 9 patients (15%) became colonized. In multiple logistic regression analyses, the use of a urinary catheter for > or =5 days (P = .006), postoperative bleeding at the surgical site (P = .009), and preoperative use of fluoroquinolones (P = .08) were associated with a higher risk of colonization. Patients without any of these risk factors did not become colonized. In conclusion, nasal carriage of MRSA is frequently acquired after OLT. Periodic postoperative screening for MRSA carriage should be an integral component in programs designed to reduce nosocomial MRSA transmission in these patients. Further studies are needed to set up and validate a predictive model that could allow targeting postoperative screening to high-risk OLT recipients. 相似文献
9.
Guilherme Janson Karina Santana Cruz Donald G Woodside Angelos Metaxas Marcos Roberto de Freitas José Fernando Castanha Henriques 《American journal of orthodontics and dentofacial orthopedics》2004,126(4):451-463
The objective of this study was to evaluate the dentoskeletal changes consequent to orthodontic treatment in subjects with Class II subdivision malocclusions, treated with asymmetric extractions, compared with a normal-occlusion control group. The sample consisted of 3 groups, with 30 subjects in each: normal-occlusion subjects (group 1), untreated Class II subdivision subjects (group 2), and Class II subdivision patients treated with asymmetric extractions (group 3). All subjects had a full complement of permanent teeth at the beginning of treatment. The average ages of the subjects were 22.42, 15.76, and 18.57 years, respectively, in groups 1, 2, and 3. Measurements of relative differences in the spatial position of dental and skeletal bilateral landmarks were obtained from the submentovertex and posteroanterior cephalometric (PA) radiographs. The t test for independent samples was used to compare group 1 with groups 2 and 3 at different times. Results from the submentovertex radiograph showed that asymmetric extractions in Class II subdivision malocclusions will maintain the differences in the anteroposterior positions of right and left, maxillary and mandibular first molars, as would be expected with the treatment protocols used. There were no significant skeletal changes that could be attributed to the treatment approaches investigated or transverse collateral effects with the asymmetric mechanics used. It was also demonstrated that treatment of Class II subdivision malocclusions with asymmetric extractions produced corrections of maxillary and mandibular dental midline deviations with the midsagittal plane, without canting the occlusal plane or any other investigated horizontal plane, as seen in the PA radiograph. Treatment of Class II subdivision malocclusions with asymmetric extractions constitutes a beneficial approach to this problem. 相似文献
10.
Karina M S Freitas Marcos Roberto de Freitas José Fernando Castanha Henriques Arnaldo Pinzan Guilherme Janson 《American journal of orthodontics and dentofacial orthopedics》2004,125(4):480-487
Treatment stability is one of the most important objectives in orthodontics, but, despite decades of research, it is still agreed that the stability of aligned teeth is variable and largely unpredictable. This study aimed to evaluate the relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction. The sample comprised 40 patients of both sexes with Class I or II malocclusions who received nonextraction treatment in the mandibular arch with edgewise mechanics. Lateral cephalograms and dental casts of each patient were obtained at pretreament, posttreatment, and 5 years postretention. Relapse of mandibular anterior crowding was assessed, and associations between this relapse and other clinical factors were also investigated. Mandibular anterior crowding was measured by the Little irregularity index, and the data were evaluated by the Mann-Whitney test. The mean relapse of mandibular anterior crowding was 1.95 mm (26.54%) over the long term. No clinical factor studied was predictive of crowding relapse in the long term. 相似文献