首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2169篇
  免费   137篇
  国内免费   11篇
耳鼻咽喉   21篇
儿科学   84篇
妇产科学   51篇
基础医学   239篇
口腔科学   26篇
临床医学   246篇
内科学   495篇
皮肤病学   43篇
神经病学   144篇
特种医学   43篇
外科学   209篇
综合类   117篇
一般理论   1篇
预防医学   209篇
眼科学   18篇
药学   161篇
  1篇
中国医学   44篇
肿瘤学   165篇
  2024年   7篇
  2023年   31篇
  2022年   104篇
  2021年   152篇
  2020年   103篇
  2019年   89篇
  2018年   105篇
  2017年   81篇
  2016年   82篇
  2015年   95篇
  2014年   111篇
  2013年   132篇
  2012年   164篇
  2011年   178篇
  2010年   94篇
  2009年   77篇
  2008年   126篇
  2007年   119篇
  2006年   90篇
  2005年   92篇
  2004年   61篇
  2003年   65篇
  2002年   52篇
  2001年   15篇
  2000年   8篇
  1999年   8篇
  1998年   13篇
  1997年   11篇
  1996年   9篇
  1995年   3篇
  1994年   4篇
  1993年   5篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1985年   5篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1974年   1篇
  1973年   1篇
  1972年   3篇
  1971年   1篇
  1964年   1篇
  1963年   1篇
  1941年   1篇
  1933年   1篇
  1932年   1篇
排序方式: 共有2317条查询结果,搜索用时 78 毫秒
61.
This study investigated sterilization of used implant impression copings and healing abutments. Components were analyzed after contamination with Enterococcus foecalis, followed by multiple rounds of sterilization by both steam autoclave and Chemiclave protocols. The authors' results demonstrated that used components showed sterility equal to new components without any visible distortion. These data suggest that component resterilization and reuse may be justified or at least considered in clinical practice. Also, implications for cost savings in the placement of implants are advanced.  相似文献   
62.
Older adults are among the highest at risk for completing suicide, and they are more likely to seek mental health services from providers outside of traditional mental health care, but providers across the spectrum of care have limited training in suicide risk assessment and management and particularly lack training in suicide prevention for older adults. An educational program was developed to increase awareness and improve suicide risk assessment and management training for a range of healthcare providers who may see older adults in their care settings. One hundred thirty-two participants from two Veterans Affairs Medical Centers participated in a 6.5-hour-long workshop in the assessment and management of suicide risk in older adults. Participants were asked to complete pre- and postworkshop case notes and report on subjective changes in knowledge, attitudes, and confidence in assessment and managing suicide risk in older adults. Participants included social workers, nurses, physicians, psychologists, and occupational therapists from a variety of care settings, including outpatient and inpatient medical, outpatient and inpatient mental health, specialty clinics, home, and community. After the workshop, participants demonstrated improvement in the overall quality of case notes (P = .001), greater ability to recognize important conceptual suicide risk categories (P = .003), and reported heightened awareness of the importance of late-life suicide. The results suggest that educational training may have beneficial effect on the ability of multidisciplinary care providers to identify and manage suicide risk in elderly adults.  相似文献   
63.
C1q modulates the differentiation and function of cells committed to the monocyte-derived dendritic cell (DC) lineage. Because the 2 C1q receptors found on the DC surface-gC1qR and cC1qR-lack a direct conduit into intracellular elements, we postulated that the receptors must form complexes with transmembrane partners. In the present study, we show that DC-SIGN, a C-type lectin expressed on DCs, binds directly to C1q, as assessed by ELISA, flow cytometry, and immunoprecipitation experiments. Surface plasmon resonance analysis revealed that the interaction was specific, and both intact C1q and the globular portion of C1q bound to DC-SIGN. Whereas IgG reduced this binding significantly, the Arg residues (162-163) of the C1q-A chain, which are thought to contribute to the C1q-IgG interaction, were not required for C1q binding to DC-SIGN. Binding was reduced significantly in the absence of Ca(2+) and by preincubation of DC-SIGN with mannan, suggesting that C1q binds to DC-SIGN at its principal Ca(2+)-binding pocket, which has increased affinity for mannose residues. Antigen-capture ELISA and immunofluorescence microscopy revealed that C1q and gC1qR associate with DC-SIGN on blood DC precursors and immature DCs. The results of the present study suggest that C1q/gC1qR may regulate DC differentiation and function through the DC-SIGN-mediated induction of cell-signaling pathways.  相似文献   
64.
[摘要]目的:利用锥形束CT(codebeamcomputedtomography,CBCT)图像研究测量下颌前牙区的颌骨形态和宽度,为临床种植手术提供治疗依据。方法:选取2011年--2013年间50名成年受试者的CBCT检查结果,利用CBCT图像对下颌前牙区颌骨外形、唇舌侧宽度、近远中距离等进行观察和测量。结果:1.下颌前牙区颌骨形态唇侧均为凹形,最凹点位于下颌骨上中份,舌侧外形多样化,凸形比例最高。2.下颌骨前牙区颌骨唇舌侧宽度在下颌骨中1/2和下颌骨下缘较宽,在牙槽嵴顶和根尖区较窄。3.左右尖牙、侧切牙、中切牙于牙槽嵴顶的近远中距离是4.46~6.94mm,尖牙最长,侧切牙次之,中切牙最小。结论:下颌前牙缺失后,尤其是下颌侧切牙或中切牙个别缺失,如行种植修复近远中距离可能不足,易损伤邻牙;植入种植体等手术时应当注意下前牙区颌骨外形,避免因倒凹导致唇舌侧穿通;CBCT可作为下颌前牙区种植手术术前的常规影像学检查手段。  相似文献   
65.
66.
We retrospectively investigated the prognostic impact of high-risk cytogenetic abnormalities (CAs) on the outcome of treatment with bortezomib plus dexamethasone (BD) in 43 relapsed/refractory (Rel/Ref) multiple myeloma patients. Fluorescence in situ hybridization (FISH) analysis identified del(13q) in 25 patients, t(4;14) in 14, t(14;16) in 4, 1q21 abnormality in 12 and del(17p) in 2, while G-banding also detected chromosome 13 monosomy (-13) in metaphase spreads from 7 patients. Eighteen of 25 patients with FISH-detected chromosome 13 abnormalities also exhibited other abnormalities. Median observation period was 510 days, and median overall survival (OS) and progression-free survival (PFS) were 912 days and 162 days, respectively. Detection of del(13q), t(4;14), t(14;16) or 1q21 abnormalities by FISH and co-occurrence of chromosome 13 abnormality with other abnormalities were not associated with poorer outcomes. In contrast, detection of -13 by G-banding in metaphase spreads showed significant association with shorter OS, although the overall response rate and PFS were not inferior to those for patients without -13 detected by G-banding. BD therapy may be a potent weapon for overcoming most classical high-risk CAs, while the detection of -13 in metaphase spreads may serve as a predictor of highly progressive disease, even when treated with BD.  相似文献   
67.
68.
In Australia, HIV prevalence estimates among gay men have been mainly based on self-reported HIV status collected in annual behavioural surveys. We measured biological HIV prevalence among gay men in Melbourne, Australia, using a facility based sampling method. We calculated HIV prevalence and used logistic regression to assess correlates of a positive HIV test. A total of 639 gay men were recruited completed a survey and provided oral fluid for HIV testing from seven venues in 2008. The median age of the participants was 35 years (range 18-75 years). Overall biological HIV prevalence was 9.5% (95% CI 7.5-12.0%) compared with 6.3% (95% CI 4.5-8.4%) for self-reported HIV positive status. We found a significant discrepancy between test detected biological and self-report HIV status in our study, with 19 men (31.1%) unaware of their HIV infection. These results highlight the importance of repeatable biological estimates to inform and evaluate HIV prevention strategies.  相似文献   
69.

Introduction

In laparoscopy, it often is the case that port sites are enlarged for specimen extraction. This leads to higher risk of trocar site complications, such as infection or incisional hernia. Natural orifice surgery (NOTES) is beneficial for minimizing these complications, and this is emphasized when the extracted specimen is of large volume. We have been using transgastric technique for appendectomy, cholecystectomy, and laparoscopic sleeve gastrectomy (LSG). Of these transgastric operations, we focus on the one with relatively large-organ extraction: LSG with transoral remnant extraction (TORE). We describe the details and feasibility of this procedure and compare the outcomes to conventional LSG.

Methods

All patients undergoing LSG were considered candidates for TORE and were consented for this procedure if interested after an informed discussion. Eighteen LSGs with TORE (TORE group) and ten conventional LSGs (non-TORE group) were performed from August 2010 to March 2011. We retrospectively compared these two groups for the age, sex, preoperative body mass index, operating room time, hospital stay, excess weight loss (EWL), and trocar site complications. Laparoscopic sleeve gastrectomy with TORE consists of conventional LSG and transgastric retrieval of the resected stomach. The procedure exceeds exactly the same manner as conventional LSG until the initial stapling of the stomach. For TORE, the gastrectomy is initiated 5 cm proximal to the pylorus than usual LSG to save the space for the gastrotomy used for specimen retrieval. After the gastrectomy is completed, the full thickness of the distal most part of the staple line is incised open as wide as 2 cm by using electric cautery or ultrasonic dissector. A flexible upper endoscope, which has been in the stomach already as a bougie for gastrectomy, is then guided into the peritoneal cavity through the gastrotomy. The specimen is grasped endoscopically with a snare and extracted transorally. Following this, the gastrotomy is closed laparoscopically. The final shape of the gastric sleeve is identical to the one of conventional LSG.

Results

There was no significant difference between the TORE and the non-TORE group for patients’ profile, operating room time, hospital stay, and EWL. Neither group has experienced perioperative complications. All specimens were extracted readily and safely in the TORE group. Of the ten cases in the non-TORE group, four required extension of the trocar site. No trocar site complications were found in the TORE group, whereas the extended trocar site developed panniculitis in two cases of the non-TORE group; one required panniculectomy for refractory induration.

Conclusions

TORE can be safely and easily performed by surgeons with laparoscopic and endoscopic skill, and with commonly available instruments. While producing identical outcomes, our initial experience with the TORE technique demonstrates an advantage over traditional LSG, because it minimizes trocar site complications. Transgastric organ extraction is potentially applicable to other large-organ extractions in laparoscopic surgery without excessive risk or resources. Larger case volume and longer follow-up period is awaited.  相似文献   
70.
PurposeThe purpose of this study was to investigate whether different types of dentures induced different responses to stimulations in sensory nerve underlying the denture-supporting mucosa using current perception threshold (CPT).Materials and methodsThe study population comprised 45 complete denture wearers with a mean age of 69.7 years (CD), 30 partial denture wearers (PD) with a mean age of 67.1 years, and 40 dentulous participants with a mean age of 69.0 years (Dent). Current perception threshold (CPT) on the greater palatine nerve at 2000 Hz, 250 Hz, and 5 Hz, corresponding to A-beta, A-delta, and C fibers respectively, were measured by the Neurometer® NS3000 device. The differences CPTs among CD, PD, and Dent groups were analyzed by Kruskal–Wallis test and Mann–Whitney U test with adjusting the multiple comparisons’ inflation of type 1 error rate by a Bonferroni correction.ResultsCPTs of CD, PD, and Dent group at 2000 Hz were 61.5 ± 45.8, 53.5 ± 25.3, 33.0 ± 11.4 (10?2 mA) respectively. CPTs of CD, PD, and Dent group at 250 Hz were 29.2 ± 28.2, 20.1 ± 13.2, 14.3 ± 5.9 (10?2 mA) respectively. CPTs of CD, PD, and Dent group at 5 Hz were 28.9 ± 23.4, 17.8 ± 12.2, 12.2 ± 5.6 (10?2 mA) respectively. The CPTs at all frequencies increased in the following order: Dent < PD < CD wearer. The statistical analyses showed that the different types of dentures significantly affected CPTs at 2000 Hz (p < 0.0001), 250 Hz (p < 0.0001), and 5 Hz (p < 0.0001).ConclusionThe different types of dentures induce different responses to stimulations in the sensory nerve underlying the denture-supporting mucosa.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号