全文获取类型
收费全文 | 38458篇 |
免费 | 2844篇 |
国内免费 | 122篇 |
专业分类
耳鼻咽喉 | 387篇 |
儿科学 | 1040篇 |
妇产科学 | 691篇 |
基础医学 | 5546篇 |
口腔科学 | 648篇 |
临床医学 | 4050篇 |
内科学 | 8192篇 |
皮肤病学 | 782篇 |
神经病学 | 3970篇 |
特种医学 | 1427篇 |
外国民族医学 | 11篇 |
外科学 | 5312篇 |
综合类 | 451篇 |
一般理论 | 30篇 |
预防医学 | 3112篇 |
眼科学 | 730篇 |
药学 | 2679篇 |
中国医学 | 95篇 |
肿瘤学 | 2271篇 |
出版年
2023年 | 311篇 |
2022年 | 503篇 |
2021年 | 986篇 |
2020年 | 681篇 |
2019年 | 906篇 |
2018年 | 1082篇 |
2017年 | 865篇 |
2016年 | 980篇 |
2015年 | 1031篇 |
2014年 | 1401篇 |
2013年 | 1722篇 |
2012年 | 2716篇 |
2011年 | 2831篇 |
2010年 | 1594篇 |
2009年 | 1324篇 |
2008年 | 2164篇 |
2007年 | 2312篇 |
2006年 | 2203篇 |
2005年 | 1993篇 |
2004年 | 1887篇 |
2003年 | 1590篇 |
2002年 | 1490篇 |
2001年 | 627篇 |
2000年 | 630篇 |
1999年 | 571篇 |
1998年 | 341篇 |
1997年 | 258篇 |
1996年 | 266篇 |
1995年 | 231篇 |
1994年 | 195篇 |
1993年 | 148篇 |
1992年 | 337篇 |
1991年 | 317篇 |
1990年 | 320篇 |
1989年 | 252篇 |
1988年 | 249篇 |
1987年 | 278篇 |
1986年 | 292篇 |
1985年 | 280篇 |
1984年 | 234篇 |
1983年 | 181篇 |
1982年 | 128篇 |
1979年 | 245篇 |
1978年 | 165篇 |
1977年 | 142篇 |
1976年 | 130篇 |
1974年 | 134篇 |
1973年 | 148篇 |
1972年 | 127篇 |
1971年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Meniscal transplantation using fresh and cryopreserved allografts. An experimental study in goats. 总被引:6,自引:0,他引:6
D W Jackson C A McDevitt T M Simon S P Arnoczky E A Atwell N J Silvino 《The American journal of sports medicine》1992,20(6):644-656
A comparative study of three subgroups of meniscal transplants was undertaken in the goat model: Group 1 (autograft) involved removal and immediate reimplantation of the meniscus; Group 2, fresh meniscal allografts; and Group 3, cryopreserved (30 days) meniscal allografts. Six months after surgery, tissues were evaluated for gross degenerative changes, proteoglycan concentration (as assessed by uronic acid), water content, vascularity, histology, and cell viability. The contralateral knee served as control for all comparisons. There was no statistical difference in the amount of arthritis present and all transplants demonstrated an essentially normal peripheral vascularity compared to controls. Sections revealed reduced numbers of cells in the central portions of the transplanted menisci and these viable cells demonstrated different behavior in multiplication in tissue culture compared to contralateral controls. Grossly and microscopically, the implanted menisci differed little from the controls. The measurement of proteoglycan concentration and water content of the transplanted meniscal cartilage suggest alterations that may affect the long-term mechanical properties. The autograft specimens showed the water content was very slightly increased (3% to 6%), while the proteoglycan concentration was increased (42% in terms of uronic acid). In contrast, the water content of the fresh allograft group and the cryopreserved group was increased 12% to 24%. Proteoglycan concentration in these groups was decreased up to 56% in portions of some menisci compared to controls. Fresh and cryopreserved meniscal allografts showed peripheral healing, revascularization, cellularity, and incorporation, and grossly appeared good at 6 months in the goat model. The biochemical changes in the extracellular matrix at 6 months raises questions on the long-term function of these transplanted menisci. 相似文献
32.
33.
M.D.Robert R. Bahnson M.D.B. Simon Slasky M.D.Marc S. Ernstoff M.D.Barbara F. Banner 《Urology》1990,35(6)
The ultrasonographic characteristics of an epidermoid cyst of the testicle are presented. Since these, findings are similar to other published case reports, preoperative sonographic diagnosis of this lagon may be possible. 相似文献
34.
BACKGROUND CONTEXT: The injection of various solutions aimed at producing a sclerosing effect has been used to treat soft tissues injuries (eg, inguinal hernia) for more than 100 years. In the 1930s, this treatment approach was applied to injured joints in an attempt to stimulate connective tissue repair. Although several studies have been published about this method of treatment for various orthopedic and spinal indications (termed prolotherapy), its use remains controversial. PURPOSE: To conduct a critical review of the literature on prolotherapy for spinal pain. STUDY DESIGN/SETTING: Critical review of the literature. METHODS: Computerized medical literature databases (Medline, CINAHL, Mantis, Cochrane Central Register of Controlled Trials) were searched to uncover all published information about the use of sclerosing injections in humans with spinal pain disorders. Search results were reviewed for relevance, and information was abstracted from full-text articles. RESULTS: Our search uncovered almost 200 reference materials in various media related to prolotherapy, including 31 clinical studies related to spinal pain. There were 26 observational cohorts and 5 randomized clinical trials (RCTs). Indications in these studies were low back pain (22), neck pain (3), cervical headaches (3) and dorsal or thoracic pain (3). A total of 20 sclerosing solutions were used in these studies; the most common was a mixture of dextrose 12.5%, glycerin 12.5%, phenol 1.25% and lidocaine 0.25%. Wide variations were found in treatment protocols, such as dose, number of treatments and use of adjunct therapies. Most cohort studies were only of moderate quality and varied greatly in the substances injected and the use of co-interventions. Most clinical studies reported positive results such as decreased pain or disability, although differences between treatment and control groups did not always reach statistical significance. Commonly reported adverse reactions to this treatment include temporary postinjection pain and stiffness. A handful of more serious adverse events were reported in the 1950s and 1960s with stronger or unknown solutions. CONCLUSION: Prolotherapy describes a variety of treatment approaches rather than a specific protocol. Results from clinical studies published to date indicate that it may be effective at reducing spinal pain. Great variation was found in the injection and treatment protocols used in these studies that preclude definite conclusions. Future research should focus on those solutions and protocols that are most commonly used in clinical practice and have been used in trials reporting effectiveness to help determine which patients, if any, are most likely to benefit from this treatment. 相似文献
35.
36.
37.
Robert Estes Daniel Estes Constance West Jitka Zobal-Ratner Patrick Droster John Simon 《Journal of AAPOS》2007,11(4):325-329
PURPOSE: To describe data sources and functional utility of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) workforce database and associated map files. METHODS: Population data from the 2000 U.S. Census and current listings from the AAPOS and American Academy of Ophthalmology (AAO) databases were organized to demonstrate and analyze practitioner-to-population relationships for metropolitan statistical areas nationwide. An interactive map was developed to provide an intuitive graphical display of the data. RESULTS: A total of 749 active AAPOS members were distributed in 154 of 280 defined metropolitan statistical areas. Within these areas, a 0- to 20-year age subgroup varied from 17.8% to 42.6%, with an average of 30.4%. The AAPOS member-to-million-person ratio varied from 1.3 to 27, with higher numbers generally representing regions with population bases inadequately defined by Census Bureau statistical area definitions. Ratios for a majority of larger, better-defined areas ranged from 3 to 4 AAPOS members per million persons. Sizable areas with no AAPOS member presence were identified and tabulated. AAO members with a specified pediatric practice focus who were not AAPOS members were identified in 103 areas, possibly influencing patient choices and practitioner referrals for these regions. CONCLUSIONS: The AAPOS workforce database and related interactive map display practitioner and population data that may assist physicians and planners in targeting practice development and identifying potentially underserved areas. 相似文献
38.
Thomas B?llingtoft Knudsen Simon Francis Thomsen Charlotte Suppli Ulrik Mogens Fenger Steen Nepper-Christensen Vibeke Backer 《The Journal of asthma》2007,44(4):257-260
BACKGROUND: Season of birth (SOB) has been regarded as a risk factor for atopy. The aim of this study was to explore the relationship between season of birth (SOB) and later development of atopic disease in children and adolescents. METHODS: A total of 1,007 randomly selected subjects, 7 to 17 years of age, who were living in urban Copenhagen, Denmark were studied. All participants were interviewed about respiratory symptoms and possible risk factors for atopic disease. Skin test reactivity, serum total immunoglobulin E (IgE), and airway responsiveness were measured using standard techniques. RESULTS: The overall risk of atopy, as judged by skin test reactivity and serum total IgE, was the same regardless of SOB. On the contrary, asthma was more common in subjects born in the autumn compared with subjects born during the remaining part of the year (12.4% vs. 5.6%), OR = 2.40, 95% CI (1.56-3.94), p < 0.001. This was observed both for atopic asthma OR = 2.41, 95% CI (1.25-4.64), p = 0.007, non-atopic asthma, OR = 2.35, 95% CI (1.14-4.83), p = 0.02, and house dust mite (HDM) sensitive airway hyperresponsiveness, OR = 3.00, 95% CI (1.44-6.24), p = 0.002. Rhinitis and pollen allergy were not significantly related to SOB. CONCLUSIONS: Atopy itself is independent of season of birth, whereas asthma is more prevalent among subjects born during the autumn. Regarding asthma, these results suggest that the first months of life enclose a period of particular vulnerability towards environmental risk factors, especially exposure to aeroallergens like HDM. 相似文献
39.
Scott D Simon Erik P Castle Robert G Ferrigni Paul E Andrews 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2005,9(2):205-207
PURPOSE: To determine whether a routine postoperative chest x-ray is required following uneventful laparoscopic nephrectomy to rule out pneumothorax. METHODS: From June 1999 to May 2003, 308 laparoscopic nephrectomy cases were performed by 5 different surgeons. This consisted of 121 radical nephrectomies, 106 donor nephrectomies, 29 simple nephrectomies, 29 partial nephrectomies, and 23 nephroureterectomies. Of the 308 procedures, 186 postoperative chest x-ray s were obtained in the recovery room: 183 routinely and 3 for known intraoperative diaphragmatic injuries. Routine chest x-rays were not obtained in 122 cases due to the individual surgeon's preference. Of these 122 patients, 15 underwent chest x-ray performed while hospitalized secondary to pulmonary issues or fever. RESULTS: Of the 308 cases, 4 pneumothoraces were identified on chest x-ray. Three were identified in the patients who had intraoperative identification of diaphragmatic injury. The fourth pneumothorax was identified in a patient who did not have a routine postoperative chest x-ray but did have a chest x-ray obtained due to postoperative shoulder pain. The pneumothorax in this patient resolved spontaneously. No incidental findings existed of pneumothorax in any patient who underwent routine postoperative chest x-ray. CONCLUSION: In our series, a pneumothorax was identified either intraoperatively or based on postoperative clinical findings. None of the 183 routine postoperative chest x-rays changed patient management. Routine postoperative chest x-ray is not necessary in uncomplicated laparoscopic nephrectomy. 相似文献
40.
Padmaja Yalamanchili Eric Wexler Megan Hayes Ming Yu Jody Bozek Mikhail Kagan Heike S. Radeke Michael Azure Ajay Purohit David S. Casebier Simon P. Robinson 《Journal of nuclear cardiology》2007,14(6):782-788
Background
BMS-747158-02 is a novel fluorine 18-labeled pyridazinone derivative designed for cardiac imaging. The uptake and retention
mechanisms of F-18 BMS-747158-02 in cardiac myocytes were studied in vitro, and the biodistribution of F-18 BMS-747158-02
was studied in vivo in mice.
Methods and Results
Fluorine 19 BMS-747158-01 inhibited mitochondrial complex I (MC-I) in bovine heart submitochondrial particles with an IC50 of 16.6±3 nmol/L that was comparable to the reference inhibitors of MC-1, rotenone, pyridaben, and deguelin (IC50 of 18.2±6.7 nmol/L, 19.8±2.6 nmol/L, and 23.1±1.5 nmol/L, respectively). F-18 BMS-747158-02 had high uptake in monolayers
of neonatal rat cardiomyocytes (10.3%±0.7% of incubated drug at 60 minutes) that was inhibited by 200 nmol/L of rotenone (91%±2%)
and deguelin (89%±3%). In contrast, an inactive pyridaben analog, P-0 (IC50 value>4 μmol/L in MC-1 assay), did not inhibit the binding of F-18 BMS-747158-02 in cardiomyocytes. Uptake and washout kinetics
for F-18 BMS-747158-02 in rat cardiomyocytes indicated that the time to half-maximal (t1/2) uptake was very rapid (approximately 35 seconds), and washout t1/2 for efflux of F-18 BMS-747158-02 was greater than 120 minutes. In vivo biodistribution studies in mice showed that F-18 BMS-747158-02
had substatial myocardial uptake (9.5%±0.5% of injected dose per gram) at 60 minutes and heart-to-lung and heart-to-liver
ratios of 14.1±2.5 and 8.3±0.5, respectively. Positron emission tomography imaging in the mouse allowed clear cardiac visualization
and demonstrated sustained myocardial uptake through 55 minutes.
Conclusions
F-18 BMS-747158-02 is a novel positron emission tomography cardiac tracer targeting MC-I in cardiomyocytes with rapid uptake
and slow washout. These characteristics allow fast and sustained accumulation in the heart. 相似文献