全文获取类型
收费全文 | 5035篇 |
免费 | 372篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 166篇 |
妇产科学 | 86篇 |
基础医学 | 625篇 |
口腔科学 | 155篇 |
临床医学 | 466篇 |
内科学 | 1104篇 |
皮肤病学 | 93篇 |
神经病学 | 277篇 |
特种医学 | 167篇 |
外科学 | 788篇 |
综合类 | 282篇 |
一般理论 | 5篇 |
预防医学 | 417篇 |
眼科学 | 170篇 |
药学 | 302篇 |
中国医学 | 11篇 |
肿瘤学 | 300篇 |
出版年
2023年 | 43篇 |
2022年 | 96篇 |
2021年 | 176篇 |
2020年 | 115篇 |
2019年 | 136篇 |
2018年 | 138篇 |
2017年 | 116篇 |
2016年 | 126篇 |
2015年 | 119篇 |
2014年 | 157篇 |
2013年 | 196篇 |
2012年 | 317篇 |
2011年 | 287篇 |
2010年 | 178篇 |
2009年 | 165篇 |
2008年 | 216篇 |
2007年 | 239篇 |
2006年 | 237篇 |
2005年 | 220篇 |
2004年 | 188篇 |
2003年 | 189篇 |
2002年 | 168篇 |
2001年 | 141篇 |
2000年 | 157篇 |
1999年 | 130篇 |
1998年 | 84篇 |
1997年 | 55篇 |
1996年 | 45篇 |
1995年 | 62篇 |
1994年 | 37篇 |
1993年 | 36篇 |
1992年 | 60篇 |
1991年 | 65篇 |
1990年 | 73篇 |
1989年 | 75篇 |
1988年 | 50篇 |
1987年 | 62篇 |
1986年 | 52篇 |
1985年 | 46篇 |
1984年 | 34篇 |
1983年 | 27篇 |
1982年 | 36篇 |
1981年 | 31篇 |
1980年 | 32篇 |
1979年 | 33篇 |
1978年 | 23篇 |
1977年 | 25篇 |
1976年 | 23篇 |
1975年 | 21篇 |
1973年 | 20篇 |
排序方式: 共有5439条查询结果,搜索用时 15 毫秒
61.
62.
Jazrawi LM Ong B Jazrawi AJ Rose D 《American journal of orthopedics (Belle Mead, N.J.)》2001,30(3):223-224
Synovial chondromatosis is an uncommon disorder with rare occurrence in the elbow. Case reports in the literature for elbow synovial chondromatosis have described presenting symptoms secondary to peripheral nerve compressions or localized bursitis. We discuss a case of synovial chondromatosis of the elbow that presented as an isolated soft-tissue mass over the radial head-more suggestive of a soft-tissue tumor than of synovial chondromatosis. 相似文献
63.
Finucane BT Ganapathy S Carli F Pridham JN Ong BY Shukla RC Kristoffersson AH Huizar KM Nevin K Ahlén KG;Canadian Ropivacaine Research Group 《Anesthesia and analgesia》2001,92(5):1276-1285
We evaluated the safety and efficacy of a 72-h epidural infusion of ropivacaine and measured the impact of adding fentanyl 2 microg/mL to the required infusion rate, on the quality of postoperative pain relief and the incidence of side effects, after colonic surgery. One hundred fifty-five patients scheduled for elective colonic surgery were randomized in this trial. Epidural infusions of ropivacaine 2 mg/mL with fentanyl 2 microg/mL (R + F) and without fentanyl (R) were commenced during surgery and continued for 72 h postoperatively. This was a prospective, randomized, double-blinded, multi-center trial. The median infusion rate required was less in the R + F group (9.3 vs 11.5 mL/h, P < 0.001). Median pain scores at rest and on coughing were lower in the R + F group (P < 0.0001). The incidence of hypotension was more in the R + F group (P = 0.01). Time to readiness for discharge was delayed in the R + F group (median 6.6 vs 5.5 days, P = 0.012). The addition of fentanyl to ropivacaine resulted in decreased infusion rates and enhanced pain control; however, adverse effects were increased and readiness to discharge was delayed. IMPLICATIONS: Epidural infusions of ropivacaine with and without fentanyl were administered to patients to control pain after colonic surgery. Patients who received ropivacaine with fentanyl had better pain control, increased side effects, and delayed readiness to discharge. This study questions the value of adding opioids to epidural infusions of local anesthetics. 相似文献
64.
Effects of anesthesia on pain after lower-limb amputation 总被引:1,自引:0,他引:1
OBJECTIVE: To evaluate the effects of epidural, spinal, and general anesthesia on pain after lower-limb amputation. DESIGN: Cross-sectional survey. SETTING: Postamputation clinic. PATIENTS: 150 patients who were evaluated one to 24 months after their lower-limb amputation. INTERVENTIONS: Patients received epidural, spinal, or general anesthesia for their amputation. MEASUREMENTS: Standardized questions were used to assess stump pain, phantom sensation, or phantom limb pain preoperatively and postoperatively. Pain intensity was assessed on a verbal rating scale of 0 to 10. After the interview, each patient's medical history and anesthetic record were assessed. RESULTS: Patients who had received epidural anesthesia and those who had received spinal anesthesia recalled significantly less pain in the week after their surgery (P < 0.05). After an average of 14 months, there was no difference in stump pain, phantom limb sensation, or phantom limb pain between patients who received epidural anesthesia, those who received spinal anesthesia, and those who received general anesthesia for their amputation. Phantom limb pain continued to be frequent and severe despite patients' use of opioid analgesics, amitriptyline, and gabapentin. CONCLUSIONS: Patients who received epidural anesthesia and those who received spinal anesthesia recalled better analgesia in the first week after their amputation than did patients who received general anesthesia. Anesthetic technique had no effect on stump pain, phantom limb sensation, or phantom limb pain at 14 months after lower-limb amputation. 相似文献
65.
Epithelioid sarcoma is a histologically distinct soft tissue sarcoma of high grade malignancy. We report a case of epithelioid sarcoma in a young man who presented with multiple nodules over the left forearm, with bony invasion and pulmonary metastases. The histological features of the dermal tumour were those of a malignant spindle cell tumour with positive cytokeratin and vimentin staining and differed from the classical epithelioid sarcoma in its absence of typical necrobiotic nodular epithelioid pattern. It was the clinical presentation and the histology of the subcutaneous nodules that led to the final diagnosis of epithelioid sarcoma. This case illustrates a predominance of spindle cell pattern in the dermal tumour of epithelioid sarcoma, which has previously been reported as fibroma-like variant of epithelioid sarcoma. 相似文献
66.
Recombinant human interleukin 1 beta (IL-1 beta), given intraperitoneally to mice as a single injection, significantly suppressed the development of arachidonic acid (AA)-induced ear oedema. This effect was noted 2 h after administration and for at least 5 days afterwards. IL-1 beta was effective in the dose range of 250 ng-20 micrograms/mouse. Injection of IL-1 beta per se resulted in erythema of the ears, and thus, IL-1 beta has the capacity not only to induce and augment but also to suppress inflammatory responses. Indomethacin administered as subcutaneously-implanted pellets did not influence the IL-1 beta induced-ear erythema, but suppressed to some extent the effect of IL-1 beta on the AA-induced ear oedema. 相似文献
67.
Aoki J Serruys PW van Beusekom H Ong AT McFadden EP Sianos G van der Giessen WJ Regar E de Feyter PJ Davis HR Rowland S Kutryk MJ 《Journal of the American College of Cardiology》2005,45(10):1574-1579
OBJECTIVES: This study was designed to evaluate whether rapid endothelialization of stainless steel stents with a functional endothelium prevents stent thrombosis and reduces the restenotic process. BACKGROUND: A "pro-healing" approach for prevention of post-stenting restenosis is theoretically favored over the use of cytotoxic or cytostatic local pharmacologic therapies. It is believed that the central role of the vascular endothelium is to maintain quiescence of the underlying media and adventitia. METHODS: Sixteen patients with de novo coronary artery disease were successfully treated with implantation of endothelial progenitor cell (EPC) capture stents. RESULTS: Complete procedural and angiographic success was achieved in all 16 patients. The nine-month composite major adverse cardiac and cerebrovascular events (MACCE) rate was 6.3% as a result of a symptom-driven target vessel revascularization in a single patient. There were no other MACCE despite only one month of clopidogrel treatment. At six-month follow-up, mean angiographic late luminal loss was 0.63 +/- 0.52 mm, and percent stent volume obstruction by intravascular ultrasound analysis was 27.2 +/- 20.9%. CONCLUSIONS: This first human clinical investigation of this technology demonstrates that the EPC capture coronary stent is safe and feasible for the treatment of de novo coronary artery disease. Further developments in this technology are warranted to evaluate the efficacy of this device for the treatment of coronary artery disease. 相似文献
68.
Tannistha Nandi Matthew T.G. Holden Xavier Didelot Kurosh Mehershahi Justin A. Boddey Ifor Beacham Ian Peak John Harting Primo Baybayan Yan Guo Susana Wang Lee Chee How Bernice Sim Angela Essex-Lopresti Mitali Sarkar-Tyson Michelle Nelson Sophie Smither Catherine Ong Lay Tin Aw Chua Hui Hoon Stephen Michell David J. Studholme Richard Titball Swaine L. Chen Julian Parkhill Patrick Tan 《Genome research》2015,25(1):129-141
Burkholderia pseudomallei (Bp) is the causative agent of the infectious disease melioidosis. To investigate population diversity, recombination, and horizontal gene transfer in closely related Bp isolates, we performed whole-genome sequencing (WGS) on 106 clinical, animal, and environmental strains from a restricted Asian locale. Whole-genome phylogenies resolved multiple genomic clades of Bp, largely congruent with multilocus sequence typing (MLST). We discovered widespread recombination in the Bp core genome, involving hundreds of regions associated with multiple haplotypes. Highly recombinant regions exhibited functional enrichments that may contribute to virulence. We observed clade-specific patterns of recombination and accessory gene exchange, and provide evidence that this is likely due to ongoing recombination between clade members. Reciprocally, interclade exchanges were rarely observed, suggesting mechanisms restricting gene flow between clades. Interrogation of accessory elements revealed that each clade harbored a distinct complement of restriction-modification (RM) systems, predicted to cause clade-specific patterns of DNA methylation. Using methylome sequencing, we confirmed that representative strains from separate clades indeed exhibit distinct methylation profiles. Finally, using an E. coli system, we demonstrate that Bp RM systems can inhibit uptake of non-self DNA. Our data suggest that RM systems borne on mobile elements, besides preventing foreign DNA invasion, may also contribute to limiting exchanges of genetic material between individuals of the same species. Genomic clades may thus represent functional units of genetic isolation in Bp, modulating intraspecies genetic diversity.Burkholderia pseudomallei (Bp) is the causative agent of melioidosis, a serious infectious disease of humans and animals and a leading cause of community-acquired sepsis and pneumonia in endemic regions (Currie et al. 2010). Initially thought to be confined to Southeast Asia and Northern Australia, the prevalence of Bp appears to be spreading (Wiersinga et al. 2012), and Bp has been designated a biothreat select agent in the United States. Bp can persist in extreme environmental conditions and can infect several plant and animal hosts, including birds, dolphins, and humans (Wuthiekanun et al. 1995; Howard and Inglis 2003; Sprague and Neubauer 2004; Larsen et al. 2013). Treatment of clinical melioidosis is challenging because the bacterium is inherently resistant to many antibiotics, and Bp infections can persist in humans for more than a decade (Hayden et al. 2012; Wiersinga et al. 2012).The Bp genome comprises one of the largest and most complex bacterial genomes sequenced to date. Consisting of two large circular replicons (chromosomes) with a combined 7.2-Mb genome size (Holden et al. 2004), it contains a rich arsenal of genes related to virulence (e.g., Type III and Type VI secretion systems, polysaccharide biosynthesis clusters), metabolic pathways, and environmental adaptation (Wiersinga et al. 2012). Besides conserved regions, accessory genes on mobile elements and genomic islands may also contribute to phenotypic and clinical differences in microbial behavior (Currie et al. 2000; Sim et al. 2008). Analysis of the Bp genome has revealed previously unknown toxins and mechanisms of antibiotic resistance (Chantratita et al. 2011; Cruz-Migoni et al. 2011).Most large-scale studies of Bp genetic diversity to date have analyzed strains using multilocus sequence typing (MLST). These studies have suggested a high degree of genetic variability between Bp strains and related Burkholderia species (Cheng et al. 2008), and have shown that Bp strains belonging to different sequence types (STs) can often coexist in the same locale and sometimes even within the same sample (Pitt et al. 2007; Wuthiekanun et al. 2009). However, due to the limited number of genes analyzed by MLST, these studies cannot comment on the global proportion of genetic material shared between strains of different STs nor on the relative contribution of recombination, mutation, and horizontal gene transfer on intraspecies genetic diversity. Moreover, although previous studies have applied whole-genome sequencing (WGS) to study global patterns of Bp genetic heterogeneity and evolution, earlier Bp WGS reports have been confined to a limited number of isolates (10–12) derived from diverse geographical regions (Nandi et al. 2010), where geophysical barriers likely limit the propensity of the analyzed strains to exchange genetic material. To achieve a comprehensive understanding of genetic variation among closely related Bp strains, WGS analysis of much larger strain panels, ideally performed on strains isolated from a common region and belonging to the same (or closely related) ST groups, is required.In this study, we attempted to fill this important knowledge gap by performing WGS on 106 Bp strains drawn from a restricted Asian locale (Singapore and Malaysia). The WGS data, exceeding previous Bp WGS studies by 10-fold, enabled us to identify specific genomic clades of Bp, molecular features of Bp recombination at the whole-genome level, and accessory genome features contributing to recombination and horizontal gene transfer. We found a consistent pattern of genetic separation correlating with MLST, recombination haplotypes, shared accessory genes, and restriction modification (RM) systems. We provide evidence that restriction modification, beyond its role as defense against foreign DNA invasion, may have also partitioned the Bp species by restricting gene flow, resulting in the other observed correlations. Because RM systems are widely dispersed through the bacterial kingdom, it is possible that similar principles may apply to other bacterial species, implicating a potential role for epigenetic barriers as a driver of early incipient speciation. 相似文献
69.
Desmond R. H. Mao Marcus E. H. Ong Chungli Bang Mohamed D. T. Salim Yih Yng Ng Desiree A. Lie 《Prehospital emergency care》2018,22(2):260-265
Objectives: Paramedics' decision to terminate field resuscitation without a physician present may depend on personal and external factors. This study investigates factors associated with paramedic psychological comfort with termination of resuscitation (TOR) to inform future training. Methods: We administered an anonymous survey to all practicing paramedics in a large urban Asian Emergency Medical Services system where formal TOR training had not yet been conducted and field TOR was not routinely applied. The survey assessed psychological comfort using the validated Psychological Comfort Total (PCT) scale (summed score of 28 items, with higher scores representing greater comfort). We examined scores associated with four personal (prior resolution of personal loss, knowledge of survival probability, religious affiliation and experience with death pronouncements) and two external (location of patient and perceived trust of family) factors. Data were entered into Excel and analyzed by t-tests and ANOVA. Results: Response rate was 73.6% (254/345). Respondents were 30.3 years (mean, SD 7.1) with 7.2 years (mean, SD 5.54) of practice experience. Over 60% had been involved in 6 or more field death pronouncements in the prior 12 months. Higher PCT scores were associated with prior resolution of personal loss and knowledge of survival probability. Lower PCT scores were associated with patient location in a public place and perceived family lack of trust. PCT scores were not associated with paramedic religious affiliation or number of prior death pronouncements. Conclusions: Paramedic psychological comfort with field death pronouncement is associated with personal and external factors. Since paramedic comfort is important for protocol adoption, TOR education should target not only knowledge, but also public arena management, communication skills for engaging with families, and help paramedics resolve prior personal loss. 相似文献
70.
Peter Ong Giancarlo Pirozzolo Anastasios Athanasiadis Udo Sechtem 《Clinical therapeutics》2018,40(9):1584-1590