全文获取类型
收费全文 | 56809篇 |
免费 | 4640篇 |
国内免费 | 157篇 |
专业分类
耳鼻咽喉 | 512篇 |
儿科学 | 1549篇 |
妇产科学 | 1087篇 |
基础医学 | 7538篇 |
口腔科学 | 981篇 |
临床医学 | 6276篇 |
内科学 | 10890篇 |
皮肤病学 | 820篇 |
神经病学 | 4855篇 |
特种医学 | 2337篇 |
外国民族医学 | 1篇 |
外科学 | 9410篇 |
综合类 | 832篇 |
一般理论 | 57篇 |
预防医学 | 5623篇 |
眼科学 | 1266篇 |
药学 | 4061篇 |
1篇 | |
中国医学 | 57篇 |
肿瘤学 | 3453篇 |
出版年
2023年 | 321篇 |
2022年 | 451篇 |
2021年 | 1162篇 |
2020年 | 660篇 |
2019年 | 1091篇 |
2018年 | 1318篇 |
2017年 | 962篇 |
2016年 | 1039篇 |
2015年 | 1240篇 |
2014年 | 1815篇 |
2013年 | 2522篇 |
2012年 | 3824篇 |
2011年 | 3906篇 |
2010年 | 2148篇 |
2009年 | 1912篇 |
2008年 | 3415篇 |
2007年 | 3659篇 |
2006年 | 3546篇 |
2005年 | 3443篇 |
2004年 | 3185篇 |
2003年 | 3030篇 |
2002年 | 2856篇 |
2001年 | 886篇 |
2000年 | 843篇 |
1999年 | 842篇 |
1998年 | 676篇 |
1997年 | 550篇 |
1996年 | 520篇 |
1995年 | 548篇 |
1994年 | 453篇 |
1993年 | 421篇 |
1992年 | 547篇 |
1991年 | 490篇 |
1990年 | 511篇 |
1989年 | 482篇 |
1988年 | 445篇 |
1987年 | 386篇 |
1986年 | 397篇 |
1985年 | 437篇 |
1984年 | 382篇 |
1983年 | 315篇 |
1982年 | 267篇 |
1981年 | 245篇 |
1980年 | 227篇 |
1979年 | 246篇 |
1978年 | 242篇 |
1976年 | 191篇 |
1974年 | 210篇 |
1973年 | 194篇 |
1972年 | 188篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
D. Grant Richards Kevin G. Whithear Peter C. Scott Robin B. Gasser 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2006,51(2):156-159
Coccidiosis of chickens, caused by species of Eimeria (Protozoa, Apicomplexa), is an intestinal disease of major economic importance worldwide. In the present study, the reproductive
characteristics of a precocious line (designated E. tenella Rt3+15) from Australia were investigated in chicken embryos and the implications of the findings briefly discussed. 相似文献
52.
Amit Badhwar Thomas L Forbes Marge B Lovell Alison A Dungey Sarah D McCarter Jeffrey R Scott Guy DeRose Kenneth A Harris Richard F Potter 《Canadian journal of surgery》2004,47(5):352-358
BACKGROUND: Ischemic preconditioning (IPC) has been found in animals to have a protective effect against future ischemic injury to muscle tissue. Such injury is unavoidable during some surgical procedures. To determine whether chronic ischemia in the lower extremities would imitate IPC and reduce ischemic injury during vascular surgery, we designed a controlled clinical study. PATIENTS AND METHODS: Two groups of patients at a university-affiliated medical centre with chronic lower-extremity ischemia served as models of IPC: 6 patients awaiting femoral distal bypass (FDB) and 4 scheduled for aortobifemoral (ABF) bypass grafting for aortoiliac occlusive disease. Seven patients undergoing elective open repair of an infrarenal abdominal aortic aneurysm (AAA) were chosen as non-IPC controls. Three hematologic indicators of skeletal-muscle injury, lactate dehydrogenase (LDH), creatine kinase (CK) and myoglobin, were measured before placement of the proximal clamp, during surgical ischemia, immediately upon reperfusion, 15 minutes after and 1 hour after reperfusion, and during the first, second and third postoperative days. RESULTS: Baseline markers of skeletal-muscle injury were similar in all groups. In postreperfusion samples, concentrations of muscle-injury markers were significantly lower in the 2 PC groups than in the control group. For example, at day 2, LDH levels were increased by about 30% over baseline measures in the elective AAA (control) group, whereas levels in the FDB and ABF groups remained statistically unchanged from baseline. Myoglobin in controls had increased by 977%, but only by 160% in the FDB and 528% in the ABF groups. CK levels, in a similar trend, were 1432% higher in the control group and only 111% (FDB) and 1029% (ABF) in the study groups. Taken together, these data represent a significant level of protection. CONCLUSIONS: Patients with chronic lower-extremity ischemia suffered less severe ischemic injury after a period of acute ischemia than those with acute ischemia alone. Ischemic preconditioning is one proposed mechanism to help explain this protective effect. 相似文献
53.
Julli?tte E M van Eerd Huub J J M Rennen Wim J G Oyen Thomas D Harris D Scott Edwards Frans H M Corstens Otto C Boerman 《Journal of nuclear medicine》2004,45(10):1747-1753
Radiolabeled chemotactic peptides have been studied for their applicability to the visualization of infectious and inflammatory foci. Because a radiolabeled leukotriene B4 (LTB4) antagonist allowed visualization of intramuscular E. coli abscesses in rabbits within a few hours after injection, we decided to test the imaging characteristics of this agent in a more clinically relevant model of pulmonary aspergillosis. The pharmacokinetics and imaging characteristics of the 111In-labeled LTB4 antagonist DPC11870 were studied in New Zealand White rabbits with experimental pulmonary aspergillosis infection. The imaging characteristics of 111In-DPC11870 were compared with those of 67Ga-citrate, a radiopharmaceutical commonly used to detect pulmonary infections in patients. METHODS: Pulmonary aspergillosis was induced in the left lung of rabbits by intratracheal inoculation of 1 x 10(8) conidia of Aspergillus fumigatus. Three days after the inoculation, the rabbits received 111In-DPC11870 or 67Ga-citrate intravenously. Images were acquired at several time points up to 24 h after injection. RESULTS: Pulmonary aspergillosis was visualized with both agents. Images acquired after injection of 111In-DPC11870 showed uptake in the pulmonary lesions from 6 h after injection. Because of accumulation at the site of infection and clearance from the background, the images improved with time. Region-of-interest analysis at 24 h after injection revealed infected lung-to-normal lung ratios of 5.0 +/- 1.5 for 111In-DPC11870 and 2.9 +/- 0.6 for 67Ga-citrate. CONCLUSION: The radiolabeled LTB4 antagonist DPC11870 clearly delineated experimentally induced pulmonary aspergillosis in rabbits. Images acquired at 24 h after injection of 111In-DPC11870 were superior to those obtained after injection of 67Ga-citrate. 相似文献
54.
55.
M. Scott DeBerard Rick A. LaCaille Glen Spielmans Alan Colledge Mary Ann Parlin 《The spine journal》2009,9(3):193-203
Background contextLumbar discectomy is the most common type of back surgery performed in the United States. Outcomes after this procedure can be variable and it appears that Workers' Compensation patients might be at increased risk for poor outcomes.PurposeTo examine long-term multidimensional outcomes of lumbar discectomy within a cohort of Workers' Compensation patients from Utah and identify presurgical biopsychosocial factors related to poor outcomes.Study design/settingA retrospective cohort study consisting of a review of presurgical medical records and assessment of patient outcomes via a telephone survey. Outcomes were assessed at least 2 years postsurgery.Patient sampleA consecutive sample of 271 workers from Utah who underwent lumbar discectomy from 1994 to 1999. A total of 134 patients were surveyed at the time of follow-up.Outcome measuresPatient satisfaction, Roland-Morris Disability Questionnaire, SF-36v2, and Stauffer-Coventry Index.MethodsA retrospective review of presurgical biopsychosocial variables and outcome assessment via telephone survey was conducted.ResultsWork disability rate for the cohort was 12.7% (17/134). Analysis of patient satisfaction, back pain-related dysfunction, and the Short-Form Health Survey-36 subscales indicated approximately 25% of patients experienced poor outcomes. Older age, number of comorbid health conditions, assigned case manager, litigation, and time delay from injury to surgery were consistently statistically significant predictors (p<.05) of poor outcomes.ConclusionsResults of this study suggest that compensated back surgery patients are at greater risk for poor lumbar discectomy outcomes than noncompensation patients. Presurgery correlates of poor outcomes may be useful in identifying high-risk compensation patients. 相似文献
56.
Diana H. Yu BA ; Kimberly A. Mace PhD ; Scott L. Hansen MD ; Nancy Boudreau PhD ; David M. Young MD 《Wound repair and regeneration》2007,15(5):628-635
Insulin-like growth factor-1 (Igf-1), a critical mediator of tissue repair, is significantly decreased in diabetic wounds. Furthermore, decreased levels of hypoxia-inducible factor 1-alpha (Hif-1alpha) and its target genes are also associated with impaired wound healing in diabetic mice. The aim of our study was to examine whether the reduced levels of Igf-1 are responsible for the reduction in Hif-1alpha protein synthesis and activity in diabetic wounds. We provide evidence that Igf-1 regulates Hif-1alpha protein synthesis and activity during wound repair. In addition, Igf-1 stimulated phosphytidylinositol 3-kinase activity in diabetic fibroblasts, which, in turn, increased activation of the translational regulatory protein, p70 S6 kinase. Moreover, improved healing of diabetic wounds by addition of recombinant IGF-1 protein was associated with an increase in Hif-1alpha protein synthesis and function in vivo. 相似文献
57.
Internal Hernias: Clinical Findings,Management, and Outcomes in 49 Nonbariatric Cases 总被引:1,自引:0,他引:1
Saber Ghiassi Scott Q. Nguyen Celia M. Divino John C. Byrn Avraham Schlager 《Journal of gastrointestinal surgery》2007,11(3):291-295
Internal hernia, the protrusion of a viscus through a peritoneal or mesenteric aperture, is a rare cause of small bowel obstruction.
We report the clinical presentation, surgical management, and outcomes of one of the largest series of nonbariatric internal
hernias. Ten-year retrospective review of patients at our institution yielded 49 cases of internal hernias. Majority of patients
presented with symptoms of acute (75%) or intermittent (22%) small bowel obstruction. While 16% of CT scans were suspicious
for internal hernia, in no cases the preoperative diagnosis of internal hernia was made. The most frequent internal hernias
were transmesenteric (57.0%) and 34 hernias (69%) were caused by previous surgery. All internal hernias were reduced and the
defects were repaired. Compromised bowel was present in 22 cases and 11 patients underwent small bowel resection. The mean
postoperative hospitalization was 10.9 days. The overall mortality rate from our series is 2%, and the morbidity rate is 12%.
Transmesenteric hernias, as complications of previous surgeries, are the most prevalent internal hernias. Preoperative diagnosis
of internal hernia is extremely difficult because of the nonspecific clinical presentation. However, if discovered promptly,
internal hernias can be repaired with acceptable morbidity and mortality.
Poster presentation at Digestive Disease Week, May 22, 2006, Los Angeles, California, USA. 相似文献
58.
Marcus P Kennedy Raymond D Coakley Scott H Donaldson Robert M Aris Kathy Hohneker Joel P Wedd Michael R Knowles Peter H Gilligan James R Yankaskas 《Journal of cystic fibrosis》2007,6(4):267-273
BACKGROUND: The impact of infection with Burkholderia gladioli in cystic fibrosis, other chronic airway diseases and immunosuppressed patients is unknown. METHODS: A six-year retrospective review of all patients with B. gladioli infection was performed in a tertiary referral center with cystic fibrosis and lung transplantation programs. In addition, a targeted survey of all 251 lung transplant recipients was performed. Available B. gladioli isolates were analyzed via pulsed field gel electrophoresis. RESULTS: Thirty-five patients were culture positive for B. gladioli, including 33 CF patients. No bacteremia was identified. Isolates were available in 18 patients and all were genetically distinct. Two-thirds of these isolates were susceptible to usual anti-pseudomonal antibiotics. After acquisition, only 40% of CF patients were chronically infected (> or =2 positive cultures separated by at least 6 months). Chronic infection was associated with resistance to > or =2 antibiotic groups on initial culture and failure of eradication after antibiotic therapy. The impact of acquisition of B. gladioli infection in chronic infection was variable. Three CF patients with chronic infection underwent lung transplantation. One post-transplant patient developed a B. gladioli mediastinal abscess, which was treated successfully. CONCLUSIONS: The majority of patients' culture positive for B. gladioli at our center have CF. B. gladioli infection is often transient and is compatible with satisfactory post-lung transplantation outcomes. 相似文献
59.
Amy Diesburg-Stanwood Jill Scott Kathleen Oman Carolee Whitehill 《Journal of emergency nursing》2004,30(4):312-317
INTRODUCTION: Limited access to medical care has resulted in large numbers of patients seeking primary care for non-emergent emergency conditions in emergency departments. This influx of patients is contributing to overcrowding and delays in care for patients with emergencies. In response, a system was implemented in which persons with non-emergent medical conditions, following a medical screening examination, did not receive further ED assessment or treatment and instead were referred to community resources. The purpose of this study was to describe the characteristics of individuals who were referred to community-based services, their condition after 72 hours, and their use of follow-up health care services. METHODS: All referred cases (n=225) were reviewed for chief complaint and demographics. Phone contact was attempted after 72 hours to determine the person's condition and if community resources were utilized. RESULTS: Of the 225 cases, 52% were female, with a mean age of 33 years. Their most common chief complaints were extremity problems (16%), toothache (9%), and medication refill (8%). Follow-up phone contact was successful with 82 people (37%) an average of 14 days after their ED visit. The majority (55%) reported their condition had improved; 39%were unchanged, and 6% were worse. Thirty-one people(40%) accessed community resources and 8 (26%) returned to another emergency department. No clinically significant associations were found between patient demographics and use of community resources. DISCUSSION: Most people who were successfully contacted for follow-up and who had come to the emergency department with non-emergent chief complaints did not access community resources and their condition frequently improved. Additional studies, with improved follow-up, are needed before suggesting that referring individuals to community resources is an acceptable practice. 相似文献
60.