全文获取类型
收费全文 | 20202篇 |
免费 | 1787篇 |
国内免费 | 58篇 |
专业分类
耳鼻咽喉 | 237篇 |
儿科学 | 595篇 |
妇产科学 | 563篇 |
基础医学 | 2694篇 |
口腔科学 | 411篇 |
临床医学 | 2628篇 |
内科学 | 3862篇 |
皮肤病学 | 302篇 |
神经病学 | 1738篇 |
特种医学 | 639篇 |
外国民族医学 | 1篇 |
外科学 | 2560篇 |
综合类 | 430篇 |
一般理论 | 12篇 |
预防医学 | 1899篇 |
眼科学 | 413篇 |
药学 | 1453篇 |
中国医学 | 34篇 |
肿瘤学 | 1576篇 |
出版年
2022年 | 170篇 |
2021年 | 381篇 |
2020年 | 247篇 |
2019年 | 341篇 |
2018年 | 457篇 |
2017年 | 326篇 |
2016年 | 364篇 |
2015年 | 369篇 |
2014年 | 577篇 |
2013年 | 844篇 |
2012年 | 1128篇 |
2011年 | 1096篇 |
2010年 | 615篇 |
2009年 | 562篇 |
2008年 | 977篇 |
2007年 | 1020篇 |
2006年 | 1027篇 |
2005年 | 986篇 |
2004年 | 877篇 |
2003年 | 837篇 |
2002年 | 787篇 |
2001年 | 608篇 |
2000年 | 572篇 |
1999年 | 502篇 |
1998年 | 216篇 |
1997年 | 185篇 |
1996年 | 166篇 |
1995年 | 160篇 |
1994年 | 154篇 |
1993年 | 129篇 |
1992年 | 370篇 |
1991年 | 327篇 |
1990年 | 344篇 |
1989年 | 295篇 |
1988年 | 313篇 |
1987年 | 295篇 |
1986年 | 290篇 |
1985年 | 256篇 |
1984年 | 213篇 |
1983年 | 217篇 |
1982年 | 143篇 |
1981年 | 148篇 |
1980年 | 118篇 |
1979年 | 217篇 |
1978年 | 157篇 |
1977年 | 118篇 |
1976年 | 133篇 |
1975年 | 138篇 |
1974年 | 156篇 |
1973年 | 111篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
A 23-year-old man sustained an isolated popliteus tendon rupture while pushing a car. The diagnosis was established with the use of arthroscopy, electromyography, and Cybex testing. After the patient failed to respond to conservative therapy, the tendon rupture was surgically repaired. The patient had an uneventful recovery and returned to his preinjury level of athletic activity. Although popliteus tendon tenosynovitis as well as injury to the popliteus in association with other ligamentous knee injuries has been described, neither an isolated popliteus tendon rupture nor an arthroscopic evaluation of a popliteus tendon rupture has been reported. 相似文献
72.
73.
A method is described for the chemical measurement of calcium oxalate and phosphate crystal formation in urine. The crystals were centrifuged, washed and the oxalate measured by an immobilised oxalate oxidase technique and the phosphate by a standard centrifugal analyser procedure. The methods proved precise and recoveries were good. Calcium oxalate crystal formation after evaporation is time-dependent and this parameter must therefore be standardised. Values for normal urinary calcium oxalate crystal concentration after concentration are given. 相似文献
74.
75.
76.
Frank P MacMaster Aileen Russell Yousha Mirza Matcheri S Keshavan S Preeya Banerjee Rashmi Bhandari Courtney Boyd Michelle Lynch Michelle Rose Jennifer Ivey Gregory J Moore David R Rosenberg 《Neuropsychopharmacology》2006,59(3):252-257
BACKGROUND: Abnormalities in the limbic-hypothalamic-pituitary-adrenal (LHPA) axis have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). To our knowledge, however, no prior study has measured pituitary gland volume in OCD. METHODS: Volumetric magnetic resonance imaging studies were conducted in 31 psychotropic drug-na?ve children (10 boys, 21 girls) aged 8-17 years and 31 case-matched healthy comparison subjects. RESULTS: Pituitary volume was significantly smaller in patients with OCD as compared with healthy control subjects (11% smaller). Smaller pituitary volume in patients with OCD was associated with increased compulsive but not obsessive symptom severity. Boys with OCD had smaller pituitary gland volumes compared with control boys (20% smaller). No significant differences in pituitary volume were observed between girls with OCD and control girls. Boys with OCD had significantly smaller pituitary volumes than girls with OCD (31% smaller), whereas control boys also had smaller pituitary gland volumes compared with control girls (21% smaller). CONCLUSIONS: These findings provide new evidence of reduced pituitary volume in pediatric OCD that seems to be more prominent in male patients. The observed alterations in pituitary volume are consistent with neuroendocrine studies that have reported abnormalities in the LHPA axis in OCD. 相似文献
77.
78.
A computational approach which concomitantly determines the capacity-limited rate constants of parent drug elimination and metabolite formation is presented. The approach applies both the presently derived total excretory recovery versus dose relationships of the metabolite and the AUC versus dose relationships of the parent drug to identify the parameters. Three parent drug elimination conditions were assessed: pooled first-order, pooled Michaelis-Menten, and parallel first-order and pooled Michaelis-Menten kinetics. Model and parameter identification criteria are discussed. Literature data for theophylline and two of its metabolites in rats were examined to reveal pooled Michaelis-Menten elimination kinetics of theophylline and capacity-limited formation of the metabolites. The proposed technique is useful for quantitating commonly obtained nonlinear drug disposition data such as AUC and amount of metabolites excreted. 相似文献
79.
Enantiomerically pure hexahydroquinolinones of the structural type 9 were prepared by a variation of the Hantzsch synthesis in which an optically active acetoacetate served as a chiral auxiliary reagent. Determinations of the de and ee values are described. The absolute configurations of the optically pure products were characterized by single-crystal X-ray analysis. The antipodes 9a and 9b exhibited calcium antagonistic activities on smooth musculature; the (S)-(-)-enantiomer 9b was the more potent compound with regard to the EC50 values which differed by a factor of 100; the intrinsic activity of 9b was 1.2, compared with a value of 0.54 for 9a. On the other hand, R-(+)-9a exerted positive inotropic effects on electrically stimulated atria. The cause of these effects is discussed. 相似文献
80.
1.5 tesla magnetic resonance imaging of acute spinal trauma 总被引:2,自引:0,他引:2
Fifty patients with spinal injury above L2 were studied with MRI; forty-two had initial and followup studies permitting correlation of MRI abnormalities with neurologic improvement. Two discrete patterns of MRI abnormality were identified, presumably representing cord hemorrhage and edema respectively. A third pattern appeared to represent a mixed type of injury. The correlation between the MRI patterns of cord injury and neurologic recovery was excellent. The ability of MRI to demonstrate and characterize acute cord injury appears to exceed that of other diagnostic techniques. 相似文献