全文获取类型
收费全文 | 1324971篇 |
免费 | 96395篇 |
国内免费 | 2121篇 |
专业分类
耳鼻咽喉 | 18646篇 |
儿科学 | 43617篇 |
妇产科学 | 38678篇 |
基础医学 | 193263篇 |
口腔科学 | 36228篇 |
临床医学 | 113554篇 |
内科学 | 260433篇 |
皮肤病学 | 27201篇 |
神经病学 | 103394篇 |
特种医学 | 51845篇 |
外国民族医学 | 366篇 |
外科学 | 205640篇 |
综合类 | 27154篇 |
现状与发展 | 1篇 |
一般理论 | 355篇 |
预防医学 | 97543篇 |
眼科学 | 30120篇 |
药学 | 101293篇 |
2篇 | |
中国医学 | 2529篇 |
肿瘤学 | 71625篇 |
出版年
2018年 | 12951篇 |
2016年 | 10941篇 |
2015年 | 12676篇 |
2014年 | 17569篇 |
2013年 | 26522篇 |
2012年 | 36878篇 |
2011年 | 39342篇 |
2010年 | 23079篇 |
2009年 | 21647篇 |
2008年 | 37906篇 |
2007年 | 41131篇 |
2006年 | 41565篇 |
2005年 | 40781篇 |
2004年 | 39163篇 |
2003年 | 37992篇 |
2002年 | 37403篇 |
2001年 | 58762篇 |
2000年 | 60212篇 |
1999年 | 51348篇 |
1998年 | 14777篇 |
1997年 | 13254篇 |
1996年 | 13497篇 |
1995年 | 12797篇 |
1994年 | 12147篇 |
1993年 | 11214篇 |
1992年 | 41412篇 |
1991年 | 40746篇 |
1990年 | 40268篇 |
1989年 | 39056篇 |
1988年 | 36432篇 |
1987年 | 35636篇 |
1986年 | 34031篇 |
1985年 | 32473篇 |
1984年 | 24224篇 |
1983年 | 21049篇 |
1982年 | 12589篇 |
1981年 | 11122篇 |
1979年 | 22826篇 |
1978年 | 16073篇 |
1977年 | 13882篇 |
1976年 | 13126篇 |
1975年 | 14342篇 |
1974年 | 16842篇 |
1973年 | 16226篇 |
1972年 | 15463篇 |
1971年 | 14358篇 |
1970年 | 13366篇 |
1969年 | 12860篇 |
1968年 | 12124篇 |
1967年 | 10572篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Marilyn Hravnak Leslie A Hoffman Melissa I Saul Thomas G Zullo Julie F Cuneo Ronald V Pellegrini 《American journal of critical care》2004,13(6):499-507; discussion 508
BACKGROUND: Studies suggest that patients who undergo off-pump coronary artery bypass grafting (OPCABG) have fewer short-term complications and use fewer inpatient resources than do patients who undergo standard coronary artery bypass grafting (CABG) with extracorporeal circulation. However, dissimilarity between groups in risk factors for complications has hindered interpretation of results. OBJECTIVES: To compare the prevalence of selected complications (atrial fibrillation, stroke, reoperation, and bleeding) and inpatient resource utilization (length of stay, discharge disposition, total charges) between subjects undergoing primary isolated CABG or OPCABG who were matched with respect to key risk factors. METHODS: Retrospective, causal-comparative survey conducted in 1 center for 18 months. Patients who underwent primary isolated CABG or OPCABG were matched for sex, age (within 2 years), left ventricular ejection fraction (within 0.05), and graft-patient ratio (exact match) and compared for prevalence of new-onset atrial fibrillation, stroke, reoperation within 24 hours, and bleeding. Statistical analysis included Wilcoxon and t tests for paired comparisons. RESULTS: The sample (107 matched pairs) was 63% male, with a mean age of 66 (SD 9.5) years, a mean left ventricular ejection fraction of 0.51 (SD 0.13), and a mean graft-patient ratio of 3.41 (SD 0.74). The 2 groups did not differ significantly in New York Heart Association class (P = .43), Acute Physiology and Chronic Health Evaluation III score (P = .22), postoperative beta-blocker use (P = .73), or comorbid conditions. None of the complications examined differed significantly between pairs. CONCLUSION: Patients with comparable risk profiles have similar prevalences of selected complications after CABG and OPCABG. 相似文献
992.
C Casanova C G Cote J M Marin J P de Torres A Aguirre-Jaime R Mendez L Dordelly B R Celli 《The European respiratory journal》2007,29(3):535-540
The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160-600 m). It declined by 19% (16 m.yr(-1)) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30-50% predicted) and by 26% (15 m.yr(-1)) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases. 相似文献
993.
994.
G?khan Tun?bilek Serdar Nasir Omer Ozkan Aycan Kayik?io?lu Emin Mavili 《Nordisk plastikkirurgisk forening [and] Nordisk klubb for handkirurgi》2004,38(2):94-99
Defects in the sacrococcygeal and ischial soft tissues can be treated with gluteus maximus and posterior thigh V-Y advancement flaps. However, late complications include recurrence and dehiscence of the suture line. Increasing the amount of the soft tissues over the bony prominences and multilayered closure may have an advantage for long-term durability. We modified the V-Y advancement technique by de-epithelialising the medial parts of the flap and burying them under the opposing edge of the wound or the flap. Sixteen patients with various defects of the sacrococcygeal and ischial soft tissues were operated on using this technique. All the flaps healed well with no partial or complete loss of the flap. Three patients developed complications. The main advantage of our technique is the use of healthy tissues to obliterate the dead spaces under the edges of the wound or the opposing flap. In this way, not only the defect in the skin but the defect in the subcutaneous tissue, with its iceberg tip at the surface, is treated effectively. To have an additional layer of tissue between the bone and the superficial tissues provides an extra cushion of soft tissue and avoids putting the suture line directly over the bony prominences. We used this modification safely for both unilateral and bilateral flaps. It could also be used successfully in other parts of the body. 相似文献
995.
Peter G. Michaelson captain usaf mc Eric A. Mair colonel usaf mc 《Otolaryngology--head and neck surgery》2004,130(6):649-658
OBJECTIVE: The study goal was to critically evaluate 3 popular noninvasive treatments for snoring: an oral spray lubricant applied before bedtime, a nasal strip designed to maintain nasal valve patency, and a head-positioning pillow. STUDY DESIGN: Prospective, randomized blinded clinical trial of 3 popular noninvasive snore aids using objective acoustic snoring analysis and subjective patient and bed-partner questionnaires in 40 snoring patients. A digital recorder allowed snoring analysis with data collected in the home environment over 1 week. RESULTS: There is neither objective nor subjective benefit to the use of tested popular noninvasive snore aids. Palatal snoring, palatal loudness, average loudness of snoring, averaged palatal flutter frequency, and respiratory disturbance index did not significantly change when comparing the 3 snoring aids with no treatment. Subjective comments and complications are reviewed as well. CONCLUSION: This is the first prospective comparison trial of popular noninvasive snoring aids. There is no significant objective or subjective snoring improvement in the anti-snoring aids studied compared with the use of no aid. SIGNIFICANCE: Outcome studies aid in verifying or refuting claims made by popular noninvasive snore aids. 相似文献
996.
997.
Boudreau FG 《American journal of public health and the nation's health》1941,31(9):967-968
998.
999.
1000.
According to the guidelines, ultrasonography (US) is now established as the cross-sectional imaging technique of choice in postoperative care of colorectal carcinoma. Although conventional percutaneous US is inferior to computed tomography (CT) and magnetic resonance imaging (MRI) for detecting hepatic metastases, the application of specific contrast media has significantly increased sensitivity and specificity to 87% and 88%, respectively. The combination of US and CT/MRI achieves the highest detection rates. During follow-up of rectal carcinoma, in up to 20% of locoregional recurrences are diagnosed solely by endorectal sonography and result in repeat resection with curative intention. In noncolorectal carcinoma, US is recommended in the guidelines for following up hepatocellular carcinoma and malignant thyroid disease, but the available data are insufficient to support those recommendations. 相似文献