全文获取类型
收费全文 | 99826篇 |
免费 | 6954篇 |
国内免费 | 322篇 |
专业分类
耳鼻咽喉 | 1274篇 |
儿科学 | 2534篇 |
妇产科学 | 2308篇 |
基础医学 | 12444篇 |
口腔科学 | 2061篇 |
临床医学 | 9745篇 |
内科学 | 21758篇 |
皮肤病学 | 1065篇 |
神经病学 | 8652篇 |
特种医学 | 3358篇 |
外国民族医学 | 3篇 |
外科学 | 16254篇 |
综合类 | 1401篇 |
现状与发展 | 1篇 |
一般理论 | 75篇 |
预防医学 | 7883篇 |
眼科学 | 2649篇 |
药学 | 6341篇 |
中国医学 | 142篇 |
肿瘤学 | 7154篇 |
出版年
2023年 | 401篇 |
2022年 | 692篇 |
2021年 | 1650篇 |
2020年 | 880篇 |
2019年 | 1586篇 |
2018年 | 1908篇 |
2017年 | 1404篇 |
2016年 | 1552篇 |
2015年 | 1835篇 |
2014年 | 2726篇 |
2013年 | 4321篇 |
2012年 | 6186篇 |
2011年 | 6454篇 |
2010年 | 3621篇 |
2009年 | 3345篇 |
2008年 | 6125篇 |
2007年 | 6817篇 |
2006年 | 6516篇 |
2005年 | 6663篇 |
2004年 | 6495篇 |
2003年 | 6116篇 |
2002年 | 6104篇 |
2001年 | 793篇 |
2000年 | 546篇 |
1999年 | 767篇 |
1998年 | 1283篇 |
1997年 | 1137篇 |
1996年 | 961篇 |
1995年 | 965篇 |
1994年 | 844篇 |
1993年 | 741篇 |
1992年 | 563篇 |
1991年 | 511篇 |
1990年 | 445篇 |
1989年 | 461篇 |
1988年 | 433篇 |
1987年 | 450篇 |
1986年 | 443篇 |
1985年 | 496篇 |
1984年 | 707篇 |
1983年 | 754篇 |
1982年 | 977篇 |
1981年 | 915篇 |
1980年 | 866篇 |
1979年 | 449篇 |
1978年 | 529篇 |
1977年 | 579篇 |
1976年 | 490篇 |
1975年 | 430篇 |
1974年 | 339篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
81.
Ramona A. Cole Anita Bansal Debra M. Moriarity William A. Haber William N. Setzer 《Journal of natural medicines》2007,61(4):414-417
The leaf essential oil of Eugenia zuchowskiae from Monteverde, Costa Rica, has been obtained by hydrodistillation and analyzed by GC–MS. The principal constituents of
E. zuchowskiae leaf oil were α-pinene (28.3%), β-caryophyllene (13.2%), α-humulene (13.1%), and α-copaene (8.1%). The leaf essential oil
of E. zuchowskiae showed pronounced in-vitro cytotoxic activity against MCF-7, MDA-MB-468, and UACC-257 human tumor cell lines. The major components
showed cytotoxic activities comparable to doxorubicin (LC50 14–70 μg/ml). 相似文献
82.
83.
84.
Minimally Invasive Coronary Artery Bypass Grafting: A New Method Using an Anterior Mediastinotomy 总被引:2,自引:0,他引:2
M. Clive Robinson M.D. David R. Gross D.V.M. Ph.D. William Zeman M.D. Eric Stedje-Larsen M.D. 《Journal of cardiac surgery》1995,10(5):529-536
The benefit of internal mammary artery (IMA) grafting as a long-lasting intervention for coronary artery disease is well recognized. However, largely because they are less invasive, catheter based alternatives are frequently chosen, particularly to treat single or double vessel disease. To retain the advantages of the IMA graft, and to offset the invasiveness of conventional coronary artery bypass grafting, we developed a new minimally invasive method using an anterior mediastinotomy for treating left anterior descending (LAD) or right coronary artery disease, or both. Feasibility studies using 16 pigs and a human cadaver led to approval by the Institutional Review Board for use of this procedure to treat six patients (four men, two women; mean age, 63.8 ± 13.6 [SD] yrs) who granted informed consent. Pedicle dissection of the IMA, using video assisted thoracoscopy if necessary, was made through a 2-to 3-inch horizontal anterior mediastinotomy. The underlying LAD artery was grafted during femoral vessel cardiopulmonary bypass, with cooling to 30°C, induced ventricular fibrillation, and left ventricular venting if required. Transesophageal echocardiography performed after bypass showed that two patients maintained normal wall motion and four had improvement from the original impairment. One patient suffered a recurrence of angina 4 weeks after the procedure; recatheterization showed an acutely angled IMA, subsequently corrected by balloon angioplasty. The results of follow-up dobutamine echocardiographic stress tests were negative in all patients. With this minimally invasive approach, the procedure should provide the benefits of IMA grafting with shorter hospital stay, more rapid recovery, and less overall cost. 相似文献
85.
G. Bradley Schaefer James N. Thompson John B. Bodensteiner James M. McConnell William J. Kimberling Charles T. Gay William D. Dutton David C. Hutchings Stanton B. Gray 《Annals of neurology》1996,39(3):382-385
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors. 相似文献
86.
87.
Varsha Patki Joe Virbasius William S. Lane Ban-Hock Toh Howard S. Shpetner Silvia Corvera 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(14):7326-7330
Phosphatidylinositol 3-kinases (PI 3-kinases) have been implicated in membrane trafficking in the secretory and endocytic pathways of yeast and mammalian cells, but the molecular mechanisms by which these lipid kinases operate are not known. Here we identify a protein of 170 kDa that is rapidly released from cell membranes in response to wortmannin, a potent inhibitor of mammalian PI 3-kinases. The amino acid sequence of peptides from p170 reveal its identity to early endosomal antigen (EEA) 1, an endosomal antigen with homology to several yeast proteins genetically implicated in membrane trafficking. Immunofluorescence analysis of 3T3-L1 adipocytes with antisera against p170/EEA1 reveal a punctate peripheral pattern that becomes diffuse in response to wortmannin. In vitro, p170/EEA1 binds specifically to liposomes containing PIns(3)P, suggesting that the effect of wortmannin on cells is due to inhibition of PIns(3)P production. Thus, p170/EEA1 may define a family of proteins that mediate the regulatory effects of 3′-phosphoinositides on membrane trafficking in yeast and mammalian cells. 相似文献
88.
William M. Chadduck Duc H. Duong John M. Kast David J. Donahue 《Child's nervous system》1995,11(10):579-583
Cerebellar hemorrhage is a devastating condition with morbidity and mortality related not only to the etiology of the hemorrhage, but also to the timing of the intervention. Sixteen consecutive pediatric patients with acute cerebellar hemorrhages are presented: 6 had vascular abnormalities, 3 had tumors, and 2 had hemorrhages of unknown etiology. Thirteen of the 16 patients survived with only 1 of the 13 having persistent vegetative state as a neurologic outcome. Six of 8 patients presenting in a moribund condition had good outcomes, and 3 of 4 patients presenting with fixed and dilated pupils also had good outcomes. Thus, in contrast to adults, rapid evaluation by CT scanning, followed by the judicious use of ventricular drainage and prompt surgical treatment, have resulted in favorable outcomes in pediatric patients despite their poor clinical presentations. None of the neonates having cerebellar hemorrhages required surgical intervention; their courses could be followed clinically and with transfontanel ultrasound.Presented as a poster at the 14th Congress of the European Society for Paediatric Neurosurgery, Lyon, France, 21–23 September 1994, and the XXII Annual Meeting of the International Society for Pediatric Neurosurgery, Birmingham, UK, 25–28 September 1994 相似文献
89.
Sintov Amnon Scott William A. Gallagher Kim P. Levy Robert J. 《Pharmaceutical research》1990,7(1):28-33
Epicardial antiarrhythmic drug administration was studied as a therapeutic approach for experimental ventricular tachycardia (VT) in an open-chest dog model. Lidocaine-polyurethane matrices (28%, w/w) were formulated as a model system. Matrices were placed on the left ventricular epicardium in each of 23 anesthetized open-chest dogs with ouabain-induced VT, to evaluate effectiveness in restoring sinus rhythm. Conversion occurred in all animals treated with matrices containing 300 mg or more of lidocaine after 1.5 to 7.0 min. The matrix lidocaine content correlated linearly with the time required for conversion to sinus rhythm (r = 0.75, P = 0.0002); irrespective of matrix size the myocardial/plasma lidocaine ratio was 20.1 ± 4.2 (mean ± SD) at the time of conversion. In a separate series of five dogs without ventricular tachycardia, systolic wall thickening measured with sonomicrometers after 5 min of controlled-release lidocaine administration (500- to 1000-mg matrix lidocaine content, 7.48 ± 3.49-mg/kg dose) was only minimally diminished (–14.1%) and this effect was observed only at the site of matrix placement on the anterior-apical epicardium. In contrast, intracoronary injection of 0.3 or 1.0 mg/kg of lidocaine-HCl resulted in complete elimination of wall thickening or replacement by systolic thinning. Thus epicardial administration of lidocaine from polyurethane matrices was an effective means of treating ouabain-induced ventricular tachycardia. Regional myocardial function in the vicinity of the matrices was modified to a very limited degree, supporting the view that the matrices can be used safely, without serious risk to ventricular contractile performance. 相似文献
90.