全文获取类型
收费全文 | 793篇 |
免费 | 42篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 96篇 |
妇产科学 | 3篇 |
基础医学 | 76篇 |
口腔科学 | 29篇 |
临床医学 | 103篇 |
内科学 | 155篇 |
皮肤病学 | 22篇 |
神经病学 | 15篇 |
特种医学 | 186篇 |
外科学 | 35篇 |
综合类 | 24篇 |
预防医学 | 44篇 |
眼科学 | 14篇 |
药学 | 33篇 |
中国医学 | 1篇 |
肿瘤学 | 29篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 18篇 |
2014年 | 12篇 |
2013年 | 30篇 |
2012年 | 18篇 |
2011年 | 8篇 |
2010年 | 42篇 |
2009年 | 40篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 23篇 |
2005年 | 33篇 |
2004年 | 14篇 |
2003年 | 6篇 |
2002年 | 11篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 17篇 |
1998年 | 47篇 |
1997年 | 46篇 |
1996年 | 48篇 |
1995年 | 33篇 |
1994年 | 40篇 |
1993年 | 35篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 7篇 |
1989年 | 22篇 |
1988年 | 43篇 |
1987年 | 19篇 |
1986年 | 15篇 |
1985年 | 28篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 12篇 |
1975年 | 3篇 |
排序方式: 共有870条查询结果,搜索用时 15 毫秒
71.
Transabdominal and endovaginal pelvic sonograms were obtained in 108 nonpregnant patients referred for pelvic sonography. The studies were independently obtained by two radiologists and interpreted on the basis of identical clinical information. The sonograms were then compared for anatomic detail and abnormalities. A determination was made about which examination, if either, was superior. Follow-up was performed through a review of the medical records and follow-up studies. Overall, the endovaginal study was judged superior in 65 cases (60.2%), equal in 39 (36.1%), and inferior in four (3.7%). The authors conclude that the endovaginal examination can effectively replace the transabdominal examination as the initial approach for routine pelvic sonography. 相似文献
72.
73.
74.
Childhood scoliosis: MR imaging 总被引:2,自引:0,他引:2
Nokes SR; Murtagh FR; Jones JD d; Downing M; Arrington JA; Turetsky D; Silbiger ML 《Radiology》1987,164(3):791-797
The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n = 5), Arnold-Chiari I malformation (n = 4), spinal cord tumors (n = 2), Arnold-Chiari II malformation (n = 3), and diastematomyelia (n = 1). The advantages of MR imaging in the evaluation of the scoliotic spine in children include a high sensitivity for the occult conditions associated with scoliosis, good anatomic demonstration of the cord, and absence of bone artifacts. MR imaging is recommended as a primary imaging modality in scoliosis, following conventional radiography. 相似文献
75.
Cyano and amidino flavans, isoflavans and 3(2H)-isoflavenes were synthesized in order to study their in vitro antirhino-virus activity, by comparison with the known corresponding chloro derivatives. The activity of the new compounds was evaluated on rhinovirus 1 B infected HeLa cell cultures by examining their ability to interfere with viral cytopathic effect and with plaque formation. It was found that generally the cyano derivatives behave like the chloro compounds, whereas the amidino derivatives show a lower activity, although always dependent on the position of substituent. 相似文献
76.
Digital imaging of the chest 总被引:4,自引:0,他引:4
Fraser RG; Sanders C; Barnes GT; MacMahon H; Giger ML; Doi K; Templeton AW; Cox GG; Dwyer SJ d; Merritt CR 《Radiology》1989,171(2):297-307
During the past several years, image acquisition in nuclear medicine, computed tomography, ultrasonography, subtraction angiography, and magnetic resonance has been by digitization. Despite these advances, research in the development of digital imaging in conventional radiography has lagged behind. Although studies with a variety of digital techniques have been carried out on several fronts, we still do not possess a method that has captured the imagination of the majority of radiologists and other physicians to a point where it could replace conventional screen-film imaging. This article reviews the current status and general principles of the technology, focusing on the four digital radiographic techniques that have shown the greatest promise - film digitization, an image intensifier - based system, photostimulable phosphor plates, and a scanned projection system. The physical aspects of each of the four systems and the clinical results that have been reported to date, as well as the advantages and disadvantages of each system, are presented. 相似文献
77.
78.
目的:观察单独和配合补充肉碱和糖对大鼠红细胞流变性及抗运动疲劳能力的影响。方法:实验于2005-09/11于河北师范大学体育学院运动生理学实验室完成。①选用SD雄性大鼠72只,按随机数字表法分为4组:安静组(n=6)、安静补服组(n=18)、安慰运动组(n=12)和补服运动组(n=36)。安静补服组和补服运动组均给予3种药物形式:左旋肉碱(由沈阳东宇精细化工有限公司生产)、葡萄糖(济南利民制药有限公司生产)、肉碱和葡萄糖。安静补服组和补服运动组每天上午8∶30给予自来水溶解的肉碱和/或糖补剂,安静组和安慰运动组给予相同量的自来水。连续补充7d,补服量:肉碱组、葡萄糖组、肉碱 葡萄糖组分别为650mg/(kg·d),7g/(kg·d),325mg/(kg·d) 3.5g/(kg·d)。②在实验第8天,将安静组取血4mL。安慰运动组和补服运动组进行无负重游泳至力竭,然后取血。采用北京泰诺德新技术研究所生产的BV-100型无摩擦式血液流变仪测全血高切黏度(180s-1)、全血高切还原黏度(180s-1)、全血低切黏度(3s-1)、全血低切还原黏度(3s-1)、刚性指数及聚集指数。③计量资料进行正态分布、方差齐性检验后,再进行方差分析。结果:大鼠72只均进入结果分析。①红细胞流变性指标变化:安静补服组各组虽大部分红细胞流变性指标有改善,但与安静组相比,差异无显著性意义(P>0.05)。安慰运动组运动后5min全血高切黏度和全血高切还原黏度明显高于安静组(P<0.01),运动24h后全血高、低切黏度和红细胞聚集指数明显高于安静组(P<0.01)。一次力竭运动后5min各补服运动组全血低切黏度明显低于安慰运动组(P<0.01)。各组间红细胞刚性指数和红细胞聚集指数差异不明显(P>0.05)。各补服运动组间相比,补服肉碱组的全血低切还原黏度最高(P<0.01)。各补服运动组运动后24h全血低切还原黏度和红细胞聚集指数明显低于安慰运动组(P<0.05~0.01),补服肉碱和肉碱 葡萄糖运动组全血低切还原黏度和全血低切黏度、红细胞聚集指数明显高于补服葡萄糖运动组(P<0.05~0.01)。②抗疲劳作用:补服肉碱、葡萄糖、肉碱 葡萄糖运动组大鼠游泳时间分别为(334.5±27.81),(321.0±51.83),(326.5±39.9)min,均长于安慰运动组[(252.5±42.69)min,P<0.01];各补服运动组间差异不明显(P>0.05)。结论:单独补充或合用肉碱和糖均有利于力竭运动后大鼠红细胞流变性指标的改善,导致其运动能力的提高。 相似文献
79.
Enhancement of t lymphocyte functions by Fc fragments of immunoglobulins. I. Augmentation of allogeneic mixed lymphocyte culture reactions requires I-A- or I-B-subregion differences between effector and stimulator cell populations 总被引:4,自引:1,他引:4
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fc fragments derived from human Ig were found to be capable of enhancing T cell-mediated, antigen-induced proliferative and mixed lymphocyte culture responses. Maximum enhancement occurred when suboptimal amounts of antigen or suboptimal numbers of stimulator cells were employed. Augmentation of the allogeneic mixed lymphocyte culture reaction requires an I-A and/or I-B subregion difference between effector and stimulator cell populations. Although a significant proliferative response was observed with K- or D- region differences, Fc fragments were unable to enhance the response. The T cell population acted upon by Fc fragments in the potentiation of these responses bears the Lyt-1(+)23(-) phenotype. 相似文献
80.
DF Stroncek ; ME Clay ; ML Petzoldt ; J Smith ; W Jaszcz ; FB Oldham ; J McCullough 《Transfusion》1996,36(7):601-610
BACKGROUND: Granulocyte-colony-stimulating factor (G-CSF) has been used in patients to increase the level of circulating hematopoietic progenitors. Although G-CSF has been administered to some healthy individuals, the kinetics of mobilization of peripheral blood stem cells (PBSCs), the optimum dose schedule and the incidence and nature of adverse reactions in normal individuals are not completely defined. STUDY DESIGN AND METHODS: Normal individuals (n = 102) who received G- CSF for 5 or 10 days at doses of 2, 5, 7.5, or 10 micrograms per kg per day were studied. The subjects were observed for symptoms and physical changes, and blood samples were obtained for a variety of laboratory tests. After 5 or 10 days of G-CSF treatment, PBSCs were collected by apheresis and analyzed. RESULTS: Overall, 89 percent of the individuals completed the 5-day treatment protocol and 88 percent completed the 10- day protocol without modification of the dose of G-CSF administered. Ninety percent of donors experienced some side effect of G-CSF. The most frequent effects noted were bone pain (83%), headache (39%), body aches (23%), fatigue (14%), and nausea and/or vomiting (12%). The dose of G-CSF administered directly affected the proportion of people with bone pain (p = 0.025) or body aches (p = 0.045) or who were feeling hot or having night sweats (p = 0.02) or taking analgesics (p = 0.01). With the 5-day dose schedule, several changes in serum chemistries occurred, including increases in alkaline phosphatase (p = 0.001), alanine aminotransferase (p = 0.0013), lactate dehydrogenase (p = 0.0001), and sodium (p = 0.0001). Decreases occurred in glucose (p = 0.045), potassium (p = 0.0004), bilirubin (p = 0.001), and blood urea nitrogen (p = 0.0017). In donors who received G-CSF for 5 days, the absolute neutrophil count was increased after one G-CSF dose, and it reached a maximum on Day 6, as did the number of CD34+ cells (64.6 +/? 55.9 × 10(6) cells/L). In those same donors, the platelet count after apheresis on Day 6 was 32 +/? 13 percent lower than pretreatment values (250 +/? 42 × 10(9) cells/L). In donors receiving G-CSF for 10 days, the neutrophil count reached a maximum on Day 8, but the number of CD34+ cells peaked on Day 6 (58.3 +/? 52.1 × 10(5) cells/L) and then declined. The platelet count decreased from pretreatment values by 28 +/? 12 percent prior to apheresis on Day 11. When individuals were treated for 5 days with G-CSF, the quantity of CD34+ cells collected was directly related to the G-CSF dose. When 5 micrograms per kg per day was given, 2.80 +/? 1.81 × 10(8) cells were collected, compared with collection of 4.67 +/? 3.11 × 10(8) cells when 10 micrograms per kg per day was given (p = 0.04). More important, PBSCs collected after 10 days of G-CSF administration (5 micrograms/kg/day) had significantly fewer CD34+ cells (0.82 +/? 0.37 × 10(8) cells, p = 0.01) than did PBSCs collected after 5 days of G-CSF (5 micrograms/kg/day). CONCLUSION: Most normal donors receiving G-CSF experience side effects, but these are mild to moderate in degree. Some alterations in blood chemistries occur, but none were clinically serious. Because of the symptoms associated with G-CSF, these individuals must be monitored closely. The treatment of normal donors with G-CSF for more than 5 days significantly decreased the number of circulating CD34+ cells and the quantity collected by apheresis. 相似文献