全文获取类型
收费全文 | 1749篇 |
免费 | 101篇 |
国内免费 | 6篇 |
学科分类
医药卫生 | 1856篇 |
出版年
2021年 | 15篇 |
2020年 | 12篇 |
2018年 | 11篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 21篇 |
2014年 | 29篇 |
2013年 | 26篇 |
2012年 | 51篇 |
2011年 | 37篇 |
2010年 | 50篇 |
2009年 | 44篇 |
2008年 | 47篇 |
2007年 | 58篇 |
2006年 | 54篇 |
2005年 | 52篇 |
2004年 | 42篇 |
2003年 | 42篇 |
2002年 | 41篇 |
2001年 | 49篇 |
2000年 | 42篇 |
1999年 | 43篇 |
1998年 | 57篇 |
1997年 | 73篇 |
1996年 | 64篇 |
1995年 | 58篇 |
1994年 | 57篇 |
1993年 | 54篇 |
1992年 | 55篇 |
1991年 | 31篇 |
1990年 | 48篇 |
1989年 | 46篇 |
1988年 | 48篇 |
1987年 | 32篇 |
1986年 | 45篇 |
1985年 | 50篇 |
1984年 | 28篇 |
1983年 | 37篇 |
1982年 | 29篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 21篇 |
1978年 | 23篇 |
1977年 | 25篇 |
1976年 | 26篇 |
1972年 | 12篇 |
1971年 | 16篇 |
1970年 | 11篇 |
1968年 | 14篇 |
1966年 | 15篇 |
排序方式: 共有1856条查询结果,搜索用时 0 毫秒
1.
2.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
3.
Occupational stress in nursing has been a popular topic for investigation. In particular, comparisons between practice areas such as the intensive care unit (ICU) and medical-surgical unit have attempted to identify what factors are stressful, and whether some nursing environments are more stressful than others. Such studies have led to inconclusive findings. While many practice areas have been studied, the neurosurgical ICU and neuromedical/neurosurgical units have largely been overlooked. Using interviews, this exploratory study examined aspects of nursing perceived as stressful by staff members working in ICU and medical-surgical units in a neuroscience center. Findings suggested that patient care, communication, workload, management and supervision, organizational and personal circumstances are major sources of stress. These findings are in keeping with studies of stress conducted in national and international non-neurosurgical nursing practice areas. 相似文献
4.
A woman with severe cicatricial conjunctival changes secondary to allopurinol-induced Stevens-Johnson syndrome developed bilateral palpebral conjunctival cysts. Pathologic examination of these lesions revealed respiratory-like pseudostratified ciliated epithelium in the walls of several cysts of one eye. To our knowledge, this is the first report of this phenomenon. 相似文献
5.
Pudendal Thigh Fasciocutaneous Flaps for Vaginal Reconstruction in Gynecologic Oncology 总被引:1,自引:0,他引:1
N. C. Gleeson W. Baile W. S. Roberts M. S. Hoffman J. V. Fiorica M. A. Finan D. Cavanagh 《Gynecologic oncology》1994,54(3)
The pudendal thigh is a sensate fasciocutaneous flap supplied by the posterior labial artery. We report on the results of pudendal thigh flaps used for vaginal reconstruction in eight patients at the time of pelvic exenteration (6) and radical vaginectomy (2). Patients were interviewed and results were assessed 5 to 19 months after surgery. The flaps were raised in the thigh creases just lateral to the hair bearing area of the labia majora and included skin, subcutaneous tissues, deep fascia of the thigh, and the epimysium of the adductor muscles. Flap sizes varied from 9 × 4 cm to 15 × 6 cm. Bilateral flaps were used in seven patients. The flaps were technically easy to perform. Partial (apical) flap necrosis occurred in four patients. One patient developed complete necrosis of bilateral flaps, followed by an enterovaginal fistula. One patient whose flaps did not necrose developed a rectovaginal fistula at the site of rectal reanastomosis. The functional results are disappointing. The only patient having successful vaginal intercourse had a unilateral flap reconstruction following lower vaginectomy in a nonirradiated pelvis. No patient with bilateral flaps or prior pelvic irradiation has had successful coitus. Other long-term sequelae include vulvar pain (2), chronic vaginal discharge (2), hair growth (4), and protrusion of the flaps (2). These vulvovaginal symptoms discourage patients and their partners from genital contact. Breaching the integrity of the vulva to construct a neovagina that is likely to be unsuitable for sexual intercourse may deprive women of their only potential for normal genital sexual responsiveness. Techniques of vaginoplasty require continued assessment. 相似文献
6.
Further experience with radiation therapy and concomitant intravenous chemotherapy in advanced carcinoma of the lower female genital tract 总被引:4,自引:1,他引:3
William S. Roberts M.D. Mitchel S. Hoffman M.D. John J. Kavanagh M.D. James V. Fiorica M.D. Harvey Greenberg M.D. Michael A. Finan M.D. Denis Cavanagh M.D. 《Gynecologic oncology》1991,43(3):233-236
Sixty-seven patients with advanced carcinoma of the lower female genital tract (cervix, vagina, and vulva) were treated with radiation and concomitant intravenous cisplatin and/or 5-fluorouracil. Fifty-seven patients (85%) responded completely clinically. Thirty-five (61%) complete responders recurred with a median time to recurrence of 6 months. Twenty-six of the thirty-five patients who recurred had some component of local failure. The 22 complete responders who have not recurred have been followed a median of 13 months. Acute toxicity was minimal, with only 6 patients requiring interruption of therapy. Nine (13%) patients developed severe late complications and eight required surgery. The actuarial 5-year survival is 22%. This treatment regimen is disappointing in terms of both survival and local control. 相似文献
7.
Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
8.
Objective . To describe the importance of migraine in Santiago, Chile, by analyzing its prevalence, clinical features and impact by age, gender and socioeconomic status. Methods . In 1993, a representative sample of 1,540 adults of the province of Santiago were interviewed using a standard questionnaire. A total of 1,385 (89.9%) subjects responded to the survey. Initially, a designated member of each household responded to the questionnaire. Subsequently, each household member with headaches was asked to respond to questions about severity, frequency, location, duration, associated symptoms and impact in work and social activities of their most frequent headaches. Migraine diagnoses were determined in accordance with the International Headache Society (IHS) criteria of 1988. Results. Recurrent headaches in the past year were found in 516 (36.82%) respondents, 145 (28.1%) males and 371 (71.9%) females. Total prevalence of migraine was found to be 7.3% (95%, CI 5.9–8.6); 11.9% (95% CI 9.6–14.2) in females and 2.0% (95% CI 0.9–3.0) in males. Overall, migraine constituted 19.6% (101/516) of all headaches reported in this sample. The prevalence did not vary significantly by age groups or socioeconomic status (SES). Migraine with aura had an overall prevalence of 3.5% (CI 0.8–7.1), and was significantly more frequent in females. In 60–70% of cases the attacks lasted 2–6 h and the frequency was 3.3 and 3.4 per month in females and males respectively. Both males and females reported significantly high percentages of attacks during work. Conclusions . Migraine prevalence in a sample of adults of Santiago is similar to that reported in previous studies using IHS criteria. Women of all socioeconomic levels are at an increased risk. 相似文献
9.
10.