全文获取类型
收费全文 | 526701篇 |
免费 | 31724篇 |
国内免费 | 1380篇 |
专业分类
耳鼻咽喉 | 6696篇 |
儿科学 | 16150篇 |
妇产科学 | 14553篇 |
基础医学 | 73703篇 |
口腔科学 | 11773篇 |
临床医学 | 47808篇 |
内科学 | 104133篇 |
皮肤病学 | 9497篇 |
神经病学 | 44191篇 |
特种医学 | 21460篇 |
外国民族医学 | 56篇 |
外科学 | 83056篇 |
综合类 | 10252篇 |
现状与发展 | 2篇 |
一般理论 | 337篇 |
预防医学 | 36139篇 |
眼科学 | 12328篇 |
药学 | 36085篇 |
1篇 | |
中国医学 | 1101篇 |
肿瘤学 | 30484篇 |
出版年
2022年 | 3108篇 |
2021年 | 7396篇 |
2020年 | 4338篇 |
2019年 | 7180篇 |
2018年 | 9529篇 |
2017年 | 6971篇 |
2016年 | 7790篇 |
2015年 | 9048篇 |
2014年 | 12701篇 |
2013年 | 18185篇 |
2012年 | 25922篇 |
2011年 | 27037篇 |
2010年 | 15956篇 |
2009年 | 14671篇 |
2008年 | 24211篇 |
2007年 | 25844篇 |
2006年 | 25217篇 |
2005年 | 24702篇 |
2004年 | 23499篇 |
2003年 | 21707篇 |
2002年 | 20716篇 |
2001年 | 15248篇 |
2000年 | 15076篇 |
1999年 | 13408篇 |
1998年 | 5757篇 |
1997年 | 4957篇 |
1996年 | 4524篇 |
1995年 | 4278篇 |
1994年 | 3844篇 |
1993年 | 3679篇 |
1992年 | 9287篇 |
1991年 | 9373篇 |
1990年 | 9051篇 |
1989年 | 8821篇 |
1988年 | 7990篇 |
1987年 | 7697篇 |
1986年 | 7355篇 |
1985年 | 7201篇 |
1984年 | 5664篇 |
1983年 | 4893篇 |
1982年 | 3489篇 |
1981年 | 3010篇 |
1979年 | 4891篇 |
1978年 | 3744篇 |
1977年 | 3176篇 |
1975年 | 3149篇 |
1974年 | 3669篇 |
1973年 | 3625篇 |
1972年 | 3299篇 |
1971年 | 3111篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
Acetabular blood flow during Bernese periacetabular osteotomy: an intraoperative study using laser Doppler flowmetry. 总被引:2,自引:0,他引:2
Axel Hempfing Michael Leunig Hubert P. Ntzli Martin Beck Reinhold Ganz 《Journal of orthopaedic research》2003,21(6):1145-1150
BACKGROUND: The blood flow to the acetabular fragment is of some concern in juxtaarticular pelvic osteotomies used for the treatment of hip dysplasia. No direct measurements have determined the effect of the Bernese periacetabular osteotomy (PAO) on acetabular perfusion. METHODS: Acetabular perfusion was measured by means of laser Doppler flowmetry in 10 patients undergoing a PAO for symptomatic acetabular dysplasia. During the surgical procedure, the intraosseous high energy laser Doppler reliably depicts dynamic changes of small vessel blood flow. Measurements were performed after defined surgical steps to obtain sequential information on the blood perfusion of the acetabular fragment. RESULTS: After complete separation of the acetabular fragment, nine out of 10 patients had pulsatile signals, but the blood flow (BF) significantly decreased by 77%. Corrective positioning of the fragment induced no further drop of the BF signal but a loss of pulsatility in six patients. After a recovery period of about 30 min following preliminary fixation of the fragment, reestablishment of the pulsatile signal and an increase of the BF signal was seen. At termination of the surgical procedure, five out of eight patients, who could be followed throughout the whole procedure, showed a clear pulsatile signal in the supraacetabular area. Bleeding of the supraacetabular cancellous surface could be observed in all acetabula. CONCLUSION: Despite careful preservation of soft tissues during the surgical procedure, a significant reduction of the blood flow in the supraacetabular region has been observed. Nevertheless, a pulsatile signal in more than 60% of the fragments after fragment correction and an increasing signal during the recovery period showed ongoing blood perfusion indicating reversible changes in the measured supraacetabular area. All osteotomies healed within eight weeks without showing signs of necrosis during a minimum follow up of 1 year. 相似文献
133.
Most authors consider the principal advantage of FG anastomoses (compared to microsurgical anastomoses) to be shorter operating time, reduced surgical trauma to oviduct stumps, and absence of tissue ischemia. These features promote reparative regeneration and decrease adhesion formation, resulting in complete recanalization of fallopian tubes. To date, the majority of work on FG is confined to the experimental development of surgical techniques. Investigations in reconstructive gynecological surgery are quite uncommon. The physical properties of FG and the positive results of available experimental studies suggest that further development of surgical techniques using FG in obstetrics and gynecology is worthwhile. 相似文献
134.
Sustained eosinophil cationic protein release into tears after a single high-dose conjunctival allergen challenge 总被引:1,自引:0,他引:1
P. G. MONTAN M. VAN HAGE-HAMSTEN O. ZETTERSTRÖM† 《Clinical and experimental allergy》1996,26(10):1125-1130
Background The appearance of eosinophils is a hallmark sign of the allergic late-phase response (LPR). Eosinophil cationic protein (ECP), a readily measurable product released from activated eosinophils, has so far not been evaluated in the ocular LPR. Objective Two sets of trials were performed in order to investigate changes of local and systemic eosinophil activity and their possible link with symptoms and hyper-reactivity in the allergic LPR in the eye. Methods In the first experiment, ECP was analysed in tears and serum and the clinical reaction was evaluated during a 72-h time–course after a single, high-dose allergen challenge out of season in one eye of 15 pollen-sensitized volunteers. In a second experiment, the hypothesis of an increased clinical response to an allergen challenge in an eye that had been provoked with allergen 48h previously was tested in nine sensitized individuals. Results In the first experiment, symptoms at 10 min and 2, 4, 6, 8 and 24 h significantly exceeded base line scores of the challenged eyes. Tear ECP was significantly elevated in challenged eyes compared to contralateral eyes at 6, 8 and 24 h. In addition, symptoms and ECP release correlated significantly at the 24-h evaluation. Serum ECP remained unchanged throughout the study period. In the second experiment, conjunctival hyperreactivity 48h after an allergen challenge was not confirmed. Conclusion ECP secretion occurs in the experimental ocular LPR and is in part associated with the magnitude of the clinical reaction, which suggests a truly pathogenic role of the activated eosinophil in pollen-induced allergic conjunctivitis. 相似文献
135.
136.
Recurrent erosion 总被引:1,自引:0,他引:1
137.
B. A. Johnson Donald R. Jasinski Gantt P. Galloway Henry Kranzler Robert Weinreib Raymond F. Anton Barbara J. Mason Michael J. Bohn Helen M. Pettinati Richard Rawson Christopher Clyde 《Psychopharmacology》1996,128(2):206-215
Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled
study to determine the safety and efficacy of the 5-HT2 receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1
week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received
weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint,
there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in
drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a
beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference
between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively
high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ
significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related
prolongation of subjects’ QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects
can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important
role for ritanserin in the treatment of alcohol dependence.
Received: 30 April 1996/Final version: 3 July 1996 相似文献
138.
Electrocardiographic symptoms were evaluated in 53 patients with an additional left-ventricular chorda (ALVC), detected by two-dimensional echocardiography. Signs of early ventricular repolarization (EVR) were identified in 45 (84.9%) patients. A transverse ALVC was more common in EVR-free patients (87.5%), as compared to patients with ALVC + EVR combinations (51.1%; p less than 0.05). 相似文献
139.
Sarah A. Taylor Jacqueline Benedetti David Schuller Stephen P. Richman Goronwy O. Broun Alexander Hantel 《Investigational new drugs》1993,11(2-3):227-229
Summary Twenty-two patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with piroxantrone 150 mg/m2 intravenously every 21 days. There were no objective responses. The 95% upper confidence bound for response is 15%. Primary toxicity was hematologic. 相似文献
140.
Jay Magaziner Eleanor M. Simonsick T. Michael Kashner J. Richard Hebel 《Journal of clinical epidemiology》1988,41(11)
The present study evaluates the response comparability between 361 elderly hip fracture patients admitted from the community to seven Baltimore area hospitals between 1984 and 1986 and interviewer selected proxies on items pertaining to patients' pre-fracture health and functional status. Agreement across items ranges from very poor to good and varies with respect to the health or functional area assessed. Proxies tend to overestimate patient disability relative to the patients themselves, especially with regard to capacity to perform instrumental activities of daily living. Although proxies who report the greatest contact with patients respond most comparably to the patients, when they do disagree, proxies with the greatest patient contact tend to overestimate patient disability. The authors suggest that attention to item construction and phrasing may improve response comparability. 相似文献