全文获取类型
收费全文 | 18404篇 |
免费 | 2077篇 |
国内免费 | 78篇 |
专业分类
耳鼻咽喉 | 311篇 |
儿科学 | 496篇 |
妇产科学 | 238篇 |
基础医学 | 1929篇 |
口腔科学 | 7084篇 |
临床医学 | 987篇 |
内科学 | 2747篇 |
皮肤病学 | 386篇 |
神经病学 | 1029篇 |
特种医学 | 321篇 |
外科学 | 1840篇 |
综合类 | 46篇 |
一般理论 | 5篇 |
预防医学 | 1248篇 |
眼科学 | 224篇 |
药学 | 807篇 |
中国医学 | 95篇 |
肿瘤学 | 766篇 |
出版年
2024年 | 28篇 |
2023年 | 418篇 |
2022年 | 239篇 |
2021年 | 448篇 |
2020年 | 374篇 |
2019年 | 384篇 |
2018年 | 667篇 |
2017年 | 603篇 |
2016年 | 665篇 |
2015年 | 766篇 |
2014年 | 949篇 |
2013年 | 1092篇 |
2012年 | 1208篇 |
2011年 | 1229篇 |
2010年 | 890篇 |
2009年 | 964篇 |
2008年 | 1029篇 |
2007年 | 927篇 |
2006年 | 891篇 |
2005年 | 732篇 |
2004年 | 707篇 |
2003年 | 742篇 |
2002年 | 640篇 |
2001年 | 360篇 |
2000年 | 332篇 |
1999年 | 340篇 |
1998年 | 311篇 |
1997年 | 270篇 |
1996年 | 249篇 |
1995年 | 221篇 |
1994年 | 207篇 |
1993年 | 161篇 |
1992年 | 192篇 |
1991年 | 132篇 |
1990年 | 148篇 |
1989年 | 100篇 |
1988年 | 135篇 |
1987年 | 118篇 |
1986年 | 72篇 |
1985年 | 89篇 |
1984年 | 90篇 |
1983年 | 73篇 |
1982年 | 65篇 |
1981年 | 42篇 |
1979年 | 28篇 |
1977年 | 25篇 |
1976年 | 28篇 |
1975年 | 26篇 |
1974年 | 23篇 |
1972年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Taking occlusal photographs can be challenging; they are by far the most difficult images to obtain. Achieving an ideal photograph of every arch may not always be possible. In patients with limited range of motion of the mandible, an oversized or hyperactive tongue, an excessive gag reflex, or reduced flexibility of lips and checks, the goal of an ideal occlusal photograph may not be achieved. Nevertheless, patience, practice, and attention to detail can often provide a satisfactory result. 相似文献
102.
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
103.
Isidoro Di Carlo Elia Pulvirenti Adriana Toro Giuseppe Corsale 《World journal of surgery》2009,33(3):520-525
Background Laparoscopic cholecystectomy is now indisputably the gold standard for managing most gallbladder diseases. However, subversion
of the Calot triangle anatomy cannot always be managed by laparoscopy and often requires a laparotomy conversion. This report
discusses our patients treated with our personal technique.
Methods Patients undergoing subtotal cholecystectomy performed by the same surgeon with a personal technique from January 1999 to
December 2007 were considered for the present study. Sex, age, symptoms, co-morbidities, diagnostic modality, time between
hospitalization and surgery, length of postsurgical hospitalization, morbidity and mortality, and follow-up were assessed.
Results Four men and six women, aged 23 to 88 years, were included. Every patient had symptoms of acute cholecystitis. Four patients
had had symptoms for an average of 2.5 days and six for an average of 5.1 h. All patients were studied by ultrasonography,
and seven underwent computed tomography. The operation was performed within 48 h in all patients. The average hospital stay
from surgery to discharge was different for patients who underwent primary open cholecystectomy (10 days, range 5–16 days)
and those having a conversion after a laparoscopic attempt (7.8 days, range 4–16 days). During the postoperative period only
one patient presented a self-limiting biliary leak. No postoperative mortality occurred. At follow-up, any recurrences of
stone in the biliary tract or newly formed pouch were recorded.
Conclusions The results suggest that this new approach can be considered effective in every instance of subversion of the normal anatomy
of Calot’s triangle. 相似文献
104.
Kevin J. Donly DDS MS 《Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.]》2005,17(6):380-380
The popularity of vital tooth whitening has increased significantly over the past two decades. Professionally supervised "in-office" and "at-home" tooth whitening methods have been documented in the literature with evidence of safety and effectiveness. Although the literature includes considerable information about vital tooth whitening in adults, minimal information is available concerning vital tooth whitening in children and adolescents.
The need to provide vital tooth whitening for children might be infrequent owing to the natural whiteness of children's teeth. However, there are circumstances when tooth whitening can be desirable for children, such as fluorosis discoloration, generalized tooth darkening, post-traumatic injury discoloration, and postorthodontic tooth discoloration.
Few well-controlled clinical trials evaluating the safety and effectiveness of vital tooth whitening in children are available in the literature, Furthermore, these published clinical trials were carried out by the same principal investigator. This review examines these trials and offers recommendations accordingly. 相似文献
The need to provide vital tooth whitening for children might be infrequent owing to the natural whiteness of children's teeth. However, there are circumstances when tooth whitening can be desirable for children, such as fluorosis discoloration, generalized tooth darkening, post-traumatic injury discoloration, and postorthodontic tooth discoloration.
Few well-controlled clinical trials evaluating the safety and effectiveness of vital tooth whitening in children are available in the literature, Furthermore, these published clinical trials were carried out by the same principal investigator. This review examines these trials and offers recommendations accordingly. 相似文献
105.
106.
Yoshikiyo Akasaka MD PhD ; Kinji Ito PhD ; Kazuko Fujita PhD ; Kazuo Komiyama DDS ; Ichiro Ono MD PhD ; Yukio Ishikawa MD PhD ; Yuri Akishima MD PhD ; Hiroko Sato MD PhD ; Toshiharu Ishii MD PhD 《Wound repair and regeneration》2005,13(4):373-382
To characterize apoptosis in keloids and the mechanisms responsible for this process, the expression of activated caspase-9 and -3 in fibroblasts obtained from keloids was analyzed. Immunohistochemistry revealed that the number of fibroblasts positive for terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) or activated caspase-9 or -3 was low but was significantly higher in keloid tissues than in normal scar tissues. Significant relationships between the number of caspase-positive fibroblasts and TUNEL-positive fibroblasts suggested that the activation of caspase-9 and -3 induces apoptosis in a subpopulation of keloid fibroblasts. All keloid fibroblast cell lines established in this study showed activation of caspase-9 and -3 after serum deprivation for 3 or 4 hours, as shown using Western blotting. Furthermore, serum deprivation-induced apoptosis in a keloid fibroblast line was blocked by a caspase-9 inhibitor (acetyl-Leu-Glu-His-Asp-al), indicating that activation of caspase-9 was necessary for the process of apoptosis in keloid fibroblasts. Although serum deprivation did not significantly change the level of apoptosis protease activating factor-1 in any of the lines, cytochrome c release was detected in cytosolic fractions of the lines after serum deprivation for 3 or 4 hours. These results strongly suggest that keloid fibroblasts are predisposed to apoptosis and cytochrome c release and that caspase-9 activation may underlie regulation of apoptosis in keloid fibroblasts in vivo. 相似文献
107.
108.
109.
110.
Anette M.C. Fransson DDS A
ke Tegelberg DDS PhD Anders Johansson DDS PhD Bengt Wenneberg DDS PhD 《American journal of orthodontics and dentofacial orthopedics》2004,126(6):687-693
The aim was to identify the incidence and types of possible adverse events in the masticatory system after treatment with a mandibular protruding device (MPD) during a 2-year period in patients with obstructive sleep apnea (OSA) or snoring. The subjects comprised 65 middle-aged patients (44 OSA patients, 21 snorers). A clinical examination and a questionnaire concerning signs and symptoms from the masticatory system were performed before, after 6 months, and after 2 years of MPD use. The frequencies of registered signs from the masticatory system, such as muscle and joint tenderness, palpation, and pain during mandibular movement, decreased significantly between baseline and the 2-year follow-up. There were significant changes in the mandibular range of protrusion (+0.7 mm, P < .001), overjet (-0.5 mm, P < .001), and overbite (-0.6 mm, P < .001) compared with the initial examination. Nine patients developed a lateral open bite during treatment, and 2 of them experienced subjective symptoms related to the altered occlusion but still used the MPD every night. No patient reported pain on opening the mouth wide or during jaw movements. Two reported tiredness on jaw function. The reported frequency of headaches was also significantly reduced (P < .01). The high compliance rate in MPD use showed that the therapy is well tolerated, but there is a risk of minor alterations in the occlusion during MPD treatment. 相似文献