全文获取类型
收费全文 | 47649篇 |
免费 | 3454篇 |
国内免费 | 194篇 |
专业分类
耳鼻咽喉 | 567篇 |
儿科学 | 998篇 |
妇产科学 | 966篇 |
基础医学 | 6600篇 |
口腔科学 | 1001篇 |
临床医学 | 4703篇 |
内科学 | 10008篇 |
皮肤病学 | 1077篇 |
神经病学 | 4548篇 |
特种医学 | 1961篇 |
外国民族医学 | 2篇 |
外科学 | 8602篇 |
综合类 | 480篇 |
一般理论 | 76篇 |
预防医学 | 2669篇 |
眼科学 | 938篇 |
药学 | 2795篇 |
中国医学 | 75篇 |
肿瘤学 | 3231篇 |
出版年
2023年 | 467篇 |
2022年 | 918篇 |
2021年 | 1712篇 |
2020年 | 1017篇 |
2019年 | 1345篇 |
2018年 | 1522篇 |
2017年 | 1024篇 |
2016年 | 1198篇 |
2015年 | 1379篇 |
2014年 | 1869篇 |
2013年 | 2177篇 |
2012年 | 3550篇 |
2011年 | 3501篇 |
2010年 | 1945篇 |
2009年 | 1724篇 |
2008年 | 2726篇 |
2007年 | 2781篇 |
2006年 | 2585篇 |
2005年 | 2404篇 |
2004年 | 2224篇 |
2003年 | 2030篇 |
2002年 | 1859篇 |
2001年 | 524篇 |
2000年 | 515篇 |
1999年 | 535篇 |
1998年 | 430篇 |
1997年 | 339篇 |
1996年 | 253篇 |
1995年 | 247篇 |
1994年 | 208篇 |
1993年 | 212篇 |
1992年 | 365篇 |
1991年 | 337篇 |
1990年 | 308篇 |
1989年 | 270篇 |
1988年 | 258篇 |
1987年 | 242篇 |
1986年 | 234篇 |
1985年 | 261篇 |
1984年 | 216篇 |
1983年 | 204篇 |
1982年 | 168篇 |
1981年 | 158篇 |
1980年 | 168篇 |
1979年 | 182篇 |
1978年 | 150篇 |
1977年 | 136篇 |
1976年 | 135篇 |
1974年 | 142篇 |
1973年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Laurie M Morgan Roland N Dickerson Kathryn H Alexander Rex O Brown Gayle Minard 《Nutrition in clinical practice》2004,19(5):511-517
BACKGROUND: The intent of this study was to ascertain the adequacy of delivery of enteral nutrition (EN) to critically ill adult multiple trauma patients and to identify potential detrimental factors that affect EN delivery. METHODS: Retrospective observational study. Trauma intensive care unit (TICU) in a university-affiliated hospital. Adult patients (>/=18 years of age) admitted to the TICU who received enteral feeding. RESULTS: Fifty-six adult patients were enrolled for study. Patients received, on average, 67% +/- 19% of what was prescribed for 5.7 +/- 2.0 days. A total of 222 occurrences for temporary discontinuation of tube feeding were identified. Gastrointestinal intolerance, as defined by a gastric residual volume of >150 mL, abdominal pain, or >3 liquid stools per day, accounted for only 11% of the occurrences for discontinuation of feeding. Surgery (27%) and diagnostic procedures (15%) represented the majority of reasons for inadequate nutrient delivery. Minor factors for EN interruptions were mechanical feeding tube problems (8%), pharmacy delivery delay (4%), and miscellaneous factors (3%). Multiple and unknown reasons contributed to 14% and 18% of the occurrences, respectively. CONCLUSIONS: Surgery and diagnostic procedures accounted for the largest factor in enteral feeding discontinuations in our critically ill trauma patients. Gastrointestinal intolerance contributed a minor role in the temporary discontinuation of enteral feeding. 相似文献
62.
Alexander M. Rokitansky 《Wiener Medizinische Wochenschrift》2004,154(19-20):454-457
63.
Sami R Achem MD Alexander Klaus MD Ronald A Hinder MD PhD Kenneth R DeVault MD 《The American journal of medicine》2004,116(10):717-718
64.
Vassilios A Lachanas Emmanuel P Prokopakis Panayotis N Christodoulou John K Hajiioannou Stylianos G Malandrakis Alexander D Karatzanis George A Velegrakis 《Otology & neurotology》2006,27(8):1162-1165
OBJECTIVE: To compare laser-assisted tympanostomy (LAT) with radiofrequency myringotomy (RFM), as well as the effectiveness of mitomycin C (MC) on the above techniques, in rabbits. STUDY DESIGN: Experimental animal research protocol. SETTING: University of Crete, School of Medicine, Medical Experimental Education and Research Center. METHODS: Bilateral myringotomies were performed under general anesthesia on 40 rabbits. LAT was performed on 20 animals (40 ears) and RFM on the remaining 20 animals (40 ears). MC (0.3 mg/mL) pledgets were applied to the right ears and saline pledgets to the left ears. Animals were monitored weekly using otomicroscopy until myringotomy closure. Kaplan-Meier survival techniques were used to compare myringotomy patency times. INTERVENTIONS: Under general anesthesia, bilateral LAT was performed on 20 rabbits and bilateral RFM on 20 rabbits. MAIN OUTCOME MEASURES: Myringotomy patency time. RESULTS: The mean patency times of the saline-treated ears were: 1.85 weeks (95% confidence interval [CI], 1.556-2.144 wk) for the LAT group and 1.70 weeks (95% CI, 1.494-1.906 wk) for the RFM group. This difference was not significant (p > 0.5). MC application significantly prolonged mean patency time (p < 0.0001) in both LAT and RFM groups. The mean patency times in the MC-treated ears were 5.45 weeks (95% CI, 5.226-5.674 wk) for the LAT group and 5.55 weeks (95% CI, 5.285-5.815 wk) for the RFM group. This difference was not significant (p > 0.5). CONCLUSION: There is no significant difference in myringotomy patency times between LAT and RFM techniques in rabbits, whereas MC significantly prolongs the patency rate of either technique. 相似文献
65.
Serum and peritoneal dialysate thyroid hormone levels in patients on continuous ambulatory peritoneal dialysis 总被引:1,自引:0,他引:1
Thyroid function tests were performed on 16 clinically euthyroid patients with end-stage renal failure undergoing regular haemodialysis or continuous ambulatory peritoneal dialysis and compared with 8 healthy subjects. The patient groups were carefully matched, especially regarding relative duration of dialysis (mean of 24 months). Total serum thyroxine, total triiodothyronine, free thyroxine, free triiodothyronine and reverse triiodothyronine were significantly lower in both patient groups than control. The thyrothrophin response to the standard thyrotrophin-releasing hormone test was delayed and blunted. Using a novel concentration technique we measured loss of T4 in peritoneal dialysate effluent and found it to be approximately 10% of daily thyroidal T4 release. 相似文献
66.
67.
L. Ostrosky-Zeichner C. Sable J. Sobel B. D. Alexander G. Donowitz V. Kan C. A. Kauffman D. Kett R. A. Larsen V. Morrison M. Nucci P. G. Pappas M. E. Bradley S. Major L. Zimmer D. Wallace W. E. Dismukes J. H. Rex 《European journal of clinical microbiology & infectious diseases》2007,26(4):271-276
The study presented here was performed in order to create a rule that identifies subjects at high risk for invasive candidiasis
in the intensive care setting. Retrospective review and statistical modelling were carried out on 2,890 patients who stayed
at least 4 days in nine hospitals in the USA and Brazil; the overall incidence of invasive candidiasis in this group was 3%
(88 cases). The best performing rule was as follows: Any systemic antibiotic (days 1–3) OR presence of a central venous catheter
(days 1–3) AND at least TWO of the following—total parenteral nutrition (days 1–3), any dialysis (days 1–3), any major surgery
(days −7–0), pancreatitis (days −7–0), any use of steroids (days −7–3), or use of other immunosuppressive agents (days −7–0).
The rate of invasive candidiasis among patients meeting the rule was 9.9%, capturing 34% of cases in the units, with the following
performance: relative risk 4.36, sensitivity 0.34, specificity 0.90, positive predictive value 0.01, and negative predictive
value 0.97. The rule may identify patients at high risk of invasive candidiasis.
Results of this project were partially presented at Focus on Fungal Infections 14, New Orleans, LA, USA, 2004. Abstract no.
51. 相似文献
68.
69.
Catalina Balaguer Alexander Palou Alberto Alonso-Fernández 《Archivos de bronconeumologia》2009,45(9):449-458
Snoring and sleep apnea-hypopnea syndrome (SAHS) are two disorders of considerable relevance due to their high prevalence in the general population and their notable morbidity and mortality, particularly in association with their harmful effects on the cardiovascular system. As well as sex, age, weight, craniofacial malformations, alcohol consumption, and use of hypnotic drugs, it has been suggested that smoking may be a risk factor for developing sleep-disordered breathing. While there is solid evidence for the independent association between snoring and smoking in both children and adults, it is still unclear whether smoking constitutes an independent risk factor for developing SAHS, despite the many studies carried out to assess this link. This is probably because the association, if it exists, is very weak. 相似文献
70.
Uta Syrbe Anja Moebes Jürgen Scholze Alexander Swidsinski Yvonne D?rffel 《Hypertension research》2007,30(6):521-528
Circulating monocytes from hypertensive patients show elevated secretion patterns of pro-inflammatory cytokines, an increased expression of adhesion molecules, and an increased adhesion to vascular endothelial cells. We tested the hypothesis that telmisartan, an angiotensin II type 1 (AT(1)) receptor antagonist, reduces the activation of circulating monocytes from hypertensive patients and diminishes the monocyte-endothelial cell adhesion. Monocytes of 20 hypertensive patients and 20 normotensive controls were isolated by density gradient centrifugation and Dynabeads, and the monocyte adhesion to human aortic endothelial cell monolayers was measured by adhesion assays. To characterize monocyte activation we assessed the expression of activity-related cell surface markers that are also involved in monocyte adhesion to endothelial cells, such as CD11a/b and CD54, as well as the chemokine receptors CCR1, CCR2 and CCR5 before and after telmisartan therapy using flow cytometry. Spontaneous adhesion of monocytes from hypertensive patients and the adhesion after stimulation with angiotensin II were significantly increased compared with those in normotensive controls (p<0.05). Treatment of hypertensive patients with the AT(1) receptor antagonist telmisartan significantly diminished the adhesion of circulating monocytes to human endothelial cells (p=0.02) despite the increase in the expressions of CD11b, CD54 and CCR5 after telmisartan therapy. Reducing monocyte adhesion may be a novel beneficial effect of the AT(1) receptor antagonist telmisartan helping to prevent vascular alterations in hypertension. The mechanism of action remains to be elucidated, since reduction in monocyte adhesion was not attributable to changes in adhesion molecule expression. 相似文献