全文获取类型
收费全文 | 16486篇 |
免费 | 1421篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 156篇 |
儿科学 | 550篇 |
妇产科学 | 459篇 |
基础医学 | 2305篇 |
口腔科学 | 367篇 |
临床医学 | 1925篇 |
内科学 | 3509篇 |
皮肤病学 | 414篇 |
神经病学 | 1520篇 |
特种医学 | 475篇 |
外科学 | 1621篇 |
综合类 | 169篇 |
一般理论 | 11篇 |
预防医学 | 1986篇 |
眼科学 | 269篇 |
药学 | 1074篇 |
1篇 | |
中国医学 | 28篇 |
肿瘤学 | 1110篇 |
出版年
2023年 | 163篇 |
2022年 | 308篇 |
2021年 | 616篇 |
2020年 | 361篇 |
2019年 | 540篇 |
2018年 | 601篇 |
2017年 | 416篇 |
2016年 | 378篇 |
2015年 | 453篇 |
2014年 | 604篇 |
2013年 | 879篇 |
2012年 | 1240篇 |
2011年 | 1243篇 |
2010年 | 670篇 |
2009年 | 594篇 |
2008年 | 935篇 |
2007年 | 1002篇 |
2006年 | 880篇 |
2005年 | 835篇 |
2004年 | 765篇 |
2003年 | 708篇 |
2002年 | 575篇 |
2001年 | 223篇 |
2000年 | 218篇 |
1999年 | 191篇 |
1998年 | 115篇 |
1997年 | 96篇 |
1996年 | 96篇 |
1995年 | 96篇 |
1994年 | 67篇 |
1993年 | 73篇 |
1992年 | 106篇 |
1991年 | 123篇 |
1990年 | 135篇 |
1989年 | 122篇 |
1988年 | 107篇 |
1987年 | 89篇 |
1986年 | 102篇 |
1985年 | 108篇 |
1984年 | 66篇 |
1983年 | 110篇 |
1982年 | 63篇 |
1981年 | 68篇 |
1980年 | 54篇 |
1979年 | 74篇 |
1978年 | 67篇 |
1977年 | 52篇 |
1975年 | 56篇 |
1973年 | 66篇 |
1972年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Preliminary outcomes and efficacy of the first 360 consecutive kyphoplasties for the treatment of painful osteoporotic vertebral compression fractures. 总被引:13,自引:0,他引:13
BACKGROUND CONTEXT: Osteoporosis is a major cause of morbidity in worldwide elderly populations. Patients may become susceptible to vertebral compression fractures (VCFs) from low-impact situations. For patients who have failed conventional, palliative medical therapy, kyphoplasty not only reduces pain associated with vertebral fractures, but also offers a minimally invasive procedure with the potential to address fracture reduction and spinal sagittal alignment. Kyphoplasty involves expanding an inflatable balloon tamp to create a cavity within a vertebral body before cement deposition. PURPOSE: To evaluate the safety and efficacy of kyphoplasty to reduce and fix painful osteoporotic VCFs. STUDY DESIGN/SETTING: A retrospective, single-arm cohort study of consecutive kyphoplasty patients treated at a single center. PATIENT SAMPLE: Three hundred sixty VCFs were treated during 254 kyphoplasty procedures on 222 osteoporotic patients (mean age, 76 years [range, 28-98]; 28% male and 72% female). OUTCOME MEASURES: Patient-reported pain ratings were examined. Cement extravasation was monitored by intraoperative fluoroscopy and on postoperative radiographs. Anterior and midline vertebral height were assessed from standing, lateral radiographs obtained preoperatively and postoperatively. The number of patients who returned with symptomatic, new fractures was monitored. Perioperative complications were recorded. Mean follow-up occurred 21 months after kyphoplasty (range, 6 months through 36 months). RESULTS: Immediate pain relief was reported by 89% of patients by the first follow-up visit. One patient experienced postoperative pain as a result of radiculopathy related to bone filler leakage into the foramen. The remaining patients had persistent pain and were diagnosed with either a new fracture or underlying degenerative disc disease. Greater than or equal to 20% restoration of lost vertebral height (anterior) was observed in 63% of fractures with an overall mean restoration of 30%, and > or = 20% restoration of lost vertebral height (midline) was detected in 69% of fractures with an overall mean restoration of 50%. In this cohort, 12% (30/254) of the patients required additional kyphoplasty procedures to treat 36 symptomatic, new adjacent and remote fractures. No device-related complications occurred. CONCLUSIONS: Kyphoplasty is a safe and effective, minimally invasive procedure for relief of pain associated with VCF. In our series we also demonstrated some restoration of vertebral height and partial correction of sagittal alignment. 相似文献
4.
Dnyanesh N Tipre James J Fox Daniel P Holt Gilbert Green Jianhua Yu Martin Pomper Robert F Dannals Frank M Bengel 《Journal of nuclear medicine》2008,49(7):1189-1195
The sympathetic nervous system of the heart plays a key role in the pathophysiology of various cardiac diseases. Small-animal models are valuable for obtaining further insight into mechanisms of cardiac disease and therapy. To determine the translational potential of cardiac neuronal imaging from rodents to humans, we characterized the rat sympathetic nervous system using 3 radiotracers that reflect different subcellular mechanisms: (11)C-meta-hydroxyephedrine (HED), a tracer of neuronal transport showing stable uptake and no washout in healthy humans; (11)C-phenylephrine (PHEN), a tracer of vesicular leakage and intraneuronal metabolic degradation with initial uptake and subsequent washout in humans; and (11)C-epinephrine (EPI), a tracer of vesicular storage with stable uptake and no washout in humans. METHODS: We used a small-animal PET system to study healthy male Wistar rats at baseline, after desipramine (DMI) pretreatment (DMI block), and with DMI injection 15 min after tracer delivery (DMI chase). The rats were kept under general isoflurane anesthesia while dynamic emission scans of the heart were recorded for 60 min after radiotracer injection. A myocardial retention index was determined by normalizing uptake at 40 min to the integral under the arterial input curve. Washout rates were determined by monoexponential fitting of myocardial time-activity curves. RESULTS: At baseline, HED showed high myocardial uptake and sustained retention, EPI showed moderate uptake and significant biphasic washout, and PHEN showed moderate uptake and monoexponential washout. The average (+/- SD) left ventricular retention index for HED, PHEN, and EPI was 7.38% +/- 0.82%/min, 3.43% +/- 0.45%/min, and 4.24% +/- 0.59%/min, respectively; the washout rate for HED, PHEN, and EPI was 0.13% +/- 0.23%/min, 1.13% +/- 0.35%/min, and 0.50% +/- 0.24%/min, respectively. The DMI chase resulted in increased washout only for HED. DMI block decreased myocardial uptake of all tracers by less than 90%. CONCLUSION: Kinetic profiles of HED in the rat myocardium were similar to those of HED in humans, suggesting comparable neuronal transport density. Unlike in humans, however, significant washout of EPI and faster washout of PHEN were encountered, consistent with high intraneuronal metabolic activity, high catecholamine turnover, and reduced vesicular storage. This evidence of increased neuronal activity in rodents has implications for translational studies of cardiac neuronal biology in humans. 相似文献
5.
Drug-resistance in Streptococcus pneumoniae isolates among Spanish middle aged and older adults with community-acquired pneumonia 总被引:1,自引:0,他引:1
Angel Vila-Corcoles Ferran Bejarano-Romero Elisabeth Salsench Olga Ochoa-Gondar Cinta de Diego Frederic Gomez-Bertomeu Xavier Raga-Luria Xavier Cliville-Guasch Victoria Arija 《BMC infectious diseases》2009,9(1):36
Background
Pneumococcal diseases remain a major cause of morbidity and mortality worldwide. Updated data on drug-resistance from different populations may be important to recognize changes in disease patterns. This study assessed current levels of penicilin resistance among Streptococcus Pneumoniae causing pneumonia in Spanish middle age and older adults. 相似文献6.
7.
Rising malpractice rates and damages to finances and reputations caused by litigation are leading risk managers to seek new solutions to reduce the frequency and severity of malpractice. Any effort to meet the challenges of malpractice must consider three areas: the informed consent process, expectation management and physician communication. Technology is emerging as an important tool that can help risk managers better address these critical areas. This article explores the realities of malpractice today — specifically the factors behind the majority of cases and discusses how new tools can help risk managers. 相似文献
8.
9.
Rakel Kling Marc Corbière Rebecca Milord Janet G Morrison Kevin Craib Annalee Yassi Claire Sidebottom Catherine Kidd Victoria Long Sharon Saunders 《AAOHN journal》2006,54(11):481-487
This study examined the use and effectiveness of the Alert assessment form. The form is part of the Alert system, used by one large acute care hospital to identify patients with a propensity for violence. All reported incidents of patient violence from August 1, 2003, through December 31, 2004, were included in patient charts. One hundred seventeen violent patient charts were reviewed and compared with 161 non-violent patient charts, randomly chosen from the same time period. Overall use of the Alert assessment form for violent and non-violent patients was 75.7% and 35.4%, respectively. The assessment form was found to have moderate sensitivity (71%) and high specificity (94%). It is reasonably effective in identifying potentially violent or aggressive patients when it is used according to protocol. Efforts to improve the tool are warranted, as is evaluation of its benefit in settings with low prevalence of violence. Also, greater effort must be taken to prevent violence once an aggressive patient has been identified. 相似文献
10.