全文获取类型
收费全文 | 490篇 |
免费 | 25篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 38篇 |
妇产科学 | 6篇 |
基础医学 | 82篇 |
口腔科学 | 2篇 |
临床医学 | 35篇 |
内科学 | 48篇 |
皮肤病学 | 7篇 |
神经病学 | 88篇 |
特种医学 | 18篇 |
外科学 | 70篇 |
综合类 | 6篇 |
预防医学 | 43篇 |
眼科学 | 27篇 |
药学 | 27篇 |
肿瘤学 | 17篇 |
出版年
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 10篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 12篇 |
2013年 | 12篇 |
2012年 | 29篇 |
2011年 | 20篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 23篇 |
2007年 | 17篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 20篇 |
2001年 | 18篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 10篇 |
1968年 | 4篇 |
1967年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有517条查询结果,搜索用时 218 毫秒
61.
Severe (grade III) tetanus occurred in three immunized patients who had high serum levels of anti-tetanus antibody. The disease was fatal in one patient. One patient had been hyperimmunized to produce commercial tetanus immune globulin. Two patients had received immunizations 1 year before presentation. Anti-tetanus antibody titers on admission were 25 IU/ml to 0.15 IU/ml by hemagglutination and ELISA assays; greater than 0.01 IU/ml is considered protective. Even though one patient had seemingly adequate anti-tetanus titers by in vitro measurement (0.20 IU), in vivo mouse protection bioassays showed a titer less than 0.01 IU/ml, implying that there may have been a hole in her immune repertoire to tetanus neurotoxin but not to toxoid. This is the first report of grade III tetanus with protective levels of antibody in the United States. The diagnosis of tetanus, nevertheless, should not be discarded solely on the basis of seemingly protective anti-tetanus titers. 相似文献
62.
The alveolar stage of intra-uterine lung development was analyzed morphometrically in 18 fetal lambs at 112, 124, 142, or 148 (term) days of gestation. The right lungs were fixed at uniform distending pressure and the tissue embedded in Epon for light microscopy. Over the whole period, right lung volume (VL) increased more rapidly than body weight to reach a mean value of 185 cm3 at term. The increase in VL was greatest between 112 and 124 days gestation. Throughout the period of study the distal lung consisted of alveolar-like air-spaces lined by walls with a single capillary system. Despite this mature morphology, further differentiation took place as established by two independent measurements. First, interalveolar wall thickness decreased from 4.12 +/- .03 microns at 112 days to 2.55 +/- .02 microns at term. Secondly, alveolar surface area increased at a greater rate than lung volume (as VL 1.06), suggesting a moderate increase in surface complexity, but not a subdivision of existing air-spaces. This latter finding was supported by numerical density values which remained fairly constant. We conclude that throughout this period active growth involves the addition of alveolar units of basically similar size. This is a similar process to the one noted previously in postpneumonectomy compensatory growth. 相似文献
63.
The penetration of inulin, sucrose, mannitol and tritiated water from the interstitial space in muscle into the vascular system 总被引:1,自引:0,他引:1
1. An isolated gastrocnemius muscle from cat was perfused with a modified Ringer fluid containing the extracellular tracers mannitol, sucrose and inulin and in some cases tritiated water (HTO). When equilibration of the tracers between the perfusate and the tissue was obtained, perfusion with tracer-free fluid was started.2. The fractional rate of escape, Phi (t), of the tracers was followed. For all tracers it declined steadily with time. The rate of decline was faster for the smaller extracellular molecules when any combination of two extracellular tracers was studied.3. Arrest of flow for 1-2 min lead to an increase in Phi (t) for the extracellular tracers when flow was resumed. There was little or no effect upon Phi (t) for HTO.4. Doubling the rate of flow had no effect upon Phi (t) for the extracellular tracers, while that of HTO increased.5. We conclude that the cause of the decline in Phi (t) for the extracellular tracers is concentration gradients in the interstitial space. The findings raise problems in methods for studying capillary permeability by means of the fractional rate of escape of tracers from the interstitial space into the vascular system. 相似文献
64.
Martin J. Buckingham Kerry R. Crone William S. Ball Thomas S. Berger 《Child's nervous system》1989,5(6):347-349
Until recently intracranial cavernous angiomas were thought to be rare vascular malformations that usually presented in adulthood as an intracerebral hemorrhage, an expanding mass lesion, or with the new onset of seizures. Prior to the advent of computed tomography (CT), and more recently magnetic resonance imaging (MRI), their diagnosis in childhood was extremely rare. However, the CT and MRI features of cavernous angioma are quite distinctive and allow early diagnosis and treatment. Advances in surgical techniques permit successful removal of these potentially devastating lesions and amelioration of the associated seizure disorder. Seven children with cerebral cavernous angiomas have been treated at the Children's Hospital Medical Center since 1980. Six children presented with seizures and one with an intracerebral hemorrhage. All had characteristic findings on CT and/or MRI and underwent surgical excision of symptomatic lesions. Intraoperative sonography, electrocorticography, and cortical mapping were used when indicated and were found to be helpful in the surgical management of these patients. Our experience suggests that symptomatic cerebral cavernous angiomas in children are not as rare as previously thought and that surgical treatment using modern neurosurgical techniques is both safe and appropriate and can be helpful in the management of associated seizures. 相似文献
65.
Eggs from immunized chickens may provide a convenient and inexpensive source of antibodies. We describe two simple and efficient methods for purification of IgG from yolk. The antibody is rendered useful for most currently employed immunological techniques. Amounts of antibody corresponding to almost half a litre of antiserum may be recovered from a chicken in one month. 相似文献
66.
67.
R. A. Crone 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1988,226(2):113-116
Most diagrams concerning binocular vision and squint contain the cyclopean eye, which is a vestige of the 2000-year-old projection theory. The author's previously published diagram is based on a motor theory of spatial localization which was been formulated by Descartes, Lotze, and Roelofs.Dedicated to Dr. G.K. von Noorden on the occasion of his 60th birthday 相似文献
68.
Two methods for prediction of postoperative vision in cataract patients have been compared: 1) Determination visual acuity in mydriasis with a stenopaeic pupil of 1 mm diameter and Landolt rings with an illumination of 5000 equivalent lux. 2) Determination of interference vision with Rodenstock's retinometer. The second method gave a value for visual acuity that averaged 1.4 times that found with the first method. The retinometer takes less time and is more reliable than the stenopaeic pupil. The causes of false negative and false positive results in the interference test are further discussed. 相似文献
69.
70.
N S Adzick J P Vacanti C W Lillehei P P O'Rourke R K Crone J M Wilson 《Journal of pediatric surgery》1989,24(7):654-7; discussion 657-8
A previously published survey has evaluated the natural history and clinical outcome of fetal diaphragmatic hernia (CDH) in 94 cases. This study showed that the prenatal diagnosis is accurate, the mortality is high (80%), and polyhydramnios is a prenatal predictor of poor clinical outcome. As a follow-up study, 38 consecutive cases of CDH diagnosed in utero were evaluated and treated by the same surgical team. This permitted detailed assessment of prognostic factors and evaluation of the impact of extracorporeal membrane oxygenation (ECMO) on outcome. We found the following. (1) Survival is poor despite optimal postnatal therapy including ECMO. (2) Polyhydramnios is both a common prenatal marker for CDH (present in 69% of fetuses) and a predictor for poor clinical outcome (only 18% survival), but tends to occur after the second trimester. (3) Amniocentesis is indicated to rule out chromosomal abnormalities that were present in 16% of fetuses. (4) All 14 fetuses diagnosed prior to 25 weeks' gestation died. Improved postnatal therapy or surgical intervention before birth will be necessary to salvage the CDH fetus with an early gestational diagnosis or associated polyhydramnios. 相似文献