全文获取类型
收费全文 | 5545篇 |
免费 | 327篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 173篇 |
妇产科学 | 169篇 |
基础医学 | 888篇 |
口腔科学 | 80篇 |
临床医学 | 457篇 |
内科学 | 1007篇 |
皮肤病学 | 175篇 |
神经病学 | 575篇 |
特种医学 | 181篇 |
外科学 | 492篇 |
综合类 | 58篇 |
预防医学 | 490篇 |
眼科学 | 303篇 |
药学 | 447篇 |
中国医学 | 10篇 |
肿瘤学 | 358篇 |
出版年
2023年 | 26篇 |
2022年 | 65篇 |
2021年 | 93篇 |
2020年 | 55篇 |
2019年 | 81篇 |
2018年 | 112篇 |
2017年 | 69篇 |
2016年 | 122篇 |
2015年 | 137篇 |
2014年 | 166篇 |
2013年 | 212篇 |
2012年 | 344篇 |
2011年 | 432篇 |
2010年 | 211篇 |
2009年 | 205篇 |
2008年 | 355篇 |
2007年 | 331篇 |
2006年 | 358篇 |
2005年 | 351篇 |
2004年 | 309篇 |
2003年 | 284篇 |
2002年 | 306篇 |
2001年 | 69篇 |
2000年 | 55篇 |
1999年 | 87篇 |
1998年 | 97篇 |
1997年 | 85篇 |
1996年 | 62篇 |
1995年 | 57篇 |
1994年 | 51篇 |
1993年 | 45篇 |
1992年 | 44篇 |
1991年 | 29篇 |
1990年 | 25篇 |
1989年 | 17篇 |
1988年 | 43篇 |
1987年 | 30篇 |
1986年 | 31篇 |
1985年 | 32篇 |
1984年 | 22篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 21篇 |
1980年 | 21篇 |
1979年 | 17篇 |
1978年 | 18篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1974年 | 15篇 |
排序方式: 共有5882条查询结果,搜索用时 31 毫秒
21.
Oluseun A Sowemimo Steven M Yood John Courtney Jessie Moore Miriam Huang Rebecca Ross Ursula McMillian Peter Ojo Randolph B Reinhold 《Surgery for obesity and related diseases》2007,3(1):73-7; discussion 77
BACKGROUND: To study the mortality among morbidly obese patients qualifying for bariatric surgery. Mortality from bariatric surgery for morbid obesity has been widely reported; however, little is known about the mortality in morbidly obese patients who defer surgery. METHODS: Consecutive patients evaluated for bariatric surgery with an initial encounter between 1997 and 2004 were identified. The Social Security Death Index and office records were used to identify mortality through 2006. We conducted telephone interviews to determine whether the 305 patients who did not undergo bariatric surgery at our institution had undergone the surgery elsewhere. Using Cox proportional hazards models, we compared the mortality in patients undergoing surgery with that of those who did not. To evaluate bias resulting from missing data, we conducted analyses assuming that all patients with missing data had (1) undergone surgery and (2) not undergone surgery. RESULTS: A total of 908 patients underwent bariatric surgery (880 patients at our institution and 28 patients elsewhere). A total of 112 patients did not undergo surgery. Data regarding surgery on 165 patients could not be obtained. The mortality in those patients who did not undergo surgery was 14.3% compared with 2.9% for those who did undergo surgery. Adjusting for age, gender, and body mass index, patients who had undergone surgery had an 82% reduction in mortality (hazard ratio 0.18, 95% confidence interval 0.09-0.35, P <.0001). Sensitivity analysis, assuming that all patients with missing data received surgery resulted in an 85% mortality reduction (P <.001) and assuming that patients did not receive surgery resulted in a 50% mortality reduction (P = .04). CONCLUSIONS: Mortality among morbidly obese patients without surgery was 14.3% during the study period. Surgical intervention offered a 50%-85% mortality reduction benefit. 相似文献
22.
Preclinical evaluation of coronary vascular function after cardioplegia with HTK and different antioxidant additives. 总被引:10,自引:0,他引:10
Cornelia Schr?der Anke Heintz Annette Pexa Ursula Rauen Andreas Deussen 《European journal of cardio-thoracic surgery》2007,31(5):821-826
OBJECTIVE: Due to limited resources, improvement of preservation solutions is still of great importance in cardiac transplant surgery. New additives with antioxidant properties were tested with respect to coronary function of isolated rat hearts. METHODS: Bretschneider HTK solution containing none or an antioxidant additive (deferoxamine, trolox or LK 616) was used for 8h cold cardioplegia. After reperfusion with Krebs-Henseleit buffer (KHB), we assessed vascular dilator capacity (bradykinin, adenosine triphosphate, reactive hyperemia), myocardial function (left ventricular developed pressure, heart rate, oxygen consumption) and release of biochemical markers (aspartate aminotransferase, creatine kinase, lactate dehydrogenase, troponin, adenosine). RESULTS: Bradykinin- and adenosine triphosphate-induced vasodilations were largely reduced in hearts stored 8h in traditional HTK as compared to unstored controls. Storage in HTK+LK 616 significantly improved bradykinin-induced vasodilation. Vasodilation toward ATP was best preserved in hearts stored in HTK+deferoxamine. Deferoxamine and trolox, both improved reactive hyperaemic response during reperfusion. Left ventricular pressure development was significantly reduced after 8h cardioplegia, but no difference existed between different cardioplegia groups. Release of biochemical markers of tissue injury was similar in all cardioplegia groups. After storage in HTK+LK 616 (100 microM), however, heart marker release was slightly augmented as compared to HTK. CONCLUSIONS: Despite similar myocardial function and marker release, coronary vascular function after cardioplegic storage may profit by addition of iron chelators (or antioxidants) to traditional HTK solution. 相似文献
23.
24.
Alexander Goldberg Ursula Schlötzer-Schrehardt Theo Seiler 《International ophthalmology》1997,21(3):117-120
We report the first case of a unilateral microcysticMeesmann‘s epithelial dystrophy, observed in the left cornea of a 43-year-old
patient. The diagnosis was verified histologically by the unilateral occurrence of a ’peculiar substance‘ within epithelial
cysts and within the cytoplasm of the corneal epithelial cells. In an attempt to resolve thepatient‘s frequent corneal erosions,
we performed an autologous stem cell transplantation from the non-involved right eye. The results are, so far, satisfactory.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
25.
Lactones, XVI: Synthesis of 4,9-Dihydropyrano[3,4-b]indol-1(3H)-ones from α-Ethoxalyl-δ-valerolactone Treatment of α-ethoxalyl-δ-valerolactone (1) with diazotized anilines and indolization of the intermediate hydrazones 4 leads to the pyranoindolones 5 . Compared to the recently reported reaction of α-ethoxalyl-γ-butyrolactone with arylhydrazines2), this synthesis is more versatile with regard to variation of substituents at the aromatic ring. Stereochemistry and reactivity of the α-arylhydrazonolactones are discussed. 相似文献
26.
27.
28.
29.
Gudrun Bornh?ft Stefanie Maxion-Bergemann Ursula Wolf Gunver S Kienle Andreas Michalsen Horst C Vollmar Simon Gilbertson Peter F Matthiessen 《BMC medical research methodology》2006,6(1):56
Background
It is often stated that external validity is not sufficiently considered in the assessment of clinical studies. Although tools for its evaluation have been established, there is a lack of awareness of their significance and application. In this article, a comprehensive checklist is presented addressing these relevant criteria. 相似文献30.
Wolfram Grimm Jens Winzenburg Ursula Knop Jürgen Hoffmann Volker Menz Frank Grote Bernhard Maisch 《Annals of noninvasive electrocardiology》1997,2(1):20-26
Objective: This prospective study was designed to compare incidence and clinical significance of ventricular late potentials between patients with idiopathic dilated cardiomyopathy (IDC) and postinfarct patients (CAD) using exactly the same method of signal-averaged electrocardiography (SAECG) in both patient groups. Methods: Time-domain analysis of SAECG was performed in 120 consecutive patients with IDC, 120 patients with CAD, and 60 healthy controls. Ventricular late potentials were detected in 27 of 120 patients with IDC (23%) compared to 41 of 120 patients with CAD (34%; P < 0.05). Results: Ventricular late potentials were found in 2 of 60 controls (3%). During 15 ± 7 months follow-up, serious arrhythmic events occurred in 17 of 120 patients with IDC (14%) and in 13 of 120 patients with CAD (11%). The sensitivity of ventricular late potentials for future arrhythmic events was 35% for IDC compared to 77% for CAD (P < 0.05). The positive predictive value of late potentials detected by time-domain analysis was 22% for IDC versus 24% for CAD (P = ns). Conclusion: In this selected patient population with IDC and CAD, time-domain analysis of SAECG revealed a lower incidence of ventricular ate potentials in patients with IDC as compared to postinfarct patients. Whereas ventricular late potentials had a high sensitivity but a low positive predictive value for identification of postinfarct patients with serious arrhythmic events during follow-up, both sensitivity and positive predictive value of ventricular late potentials for future serious arrhythmic events were low in the setting of IDC. 相似文献