全文获取类型
收费全文 | 1162篇 |
免费 | 71篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 43篇 |
妇产科学 | 14篇 |
基础医学 | 178篇 |
口腔科学 | 6篇 |
临床医学 | 66篇 |
内科学 | 193篇 |
皮肤病学 | 20篇 |
神经病学 | 264篇 |
特种医学 | 15篇 |
外科学 | 203篇 |
综合类 | 4篇 |
一般理论 | 2篇 |
预防医学 | 86篇 |
眼科学 | 15篇 |
药学 | 66篇 |
中国医学 | 1篇 |
肿瘤学 | 56篇 |
出版年
2022年 | 11篇 |
2021年 | 22篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 31篇 |
2017年 | 21篇 |
2016年 | 28篇 |
2015年 | 23篇 |
2014年 | 25篇 |
2013年 | 44篇 |
2012年 | 44篇 |
2011年 | 64篇 |
2010年 | 31篇 |
2009年 | 39篇 |
2008年 | 50篇 |
2007年 | 44篇 |
2006年 | 55篇 |
2005年 | 50篇 |
2004年 | 40篇 |
2003年 | 34篇 |
2002年 | 48篇 |
2001年 | 42篇 |
2000年 | 51篇 |
1999年 | 33篇 |
1998年 | 17篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 4篇 |
1992年 | 35篇 |
1991年 | 30篇 |
1990年 | 28篇 |
1989年 | 20篇 |
1988年 | 26篇 |
1987年 | 28篇 |
1986年 | 17篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1979年 | 12篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1974年 | 9篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有1234条查询结果,搜索用时 15 毫秒
1.
2.
Nutrition labels in bar graph format deemed most useful for consumer purchase decisions using adaptive conjoint analysis 总被引:1,自引:1,他引:0
C J Geiger B W Wyse C R Parent R G Hansen 《Journal of the American Dietetic Association》1991,91(7):800-807
This study estimated the effects of changing multiple levels and combinations of nutrition information format, load, expression, and order on consumers' perceptions of label usefulness in purchase decisions using adaptive conjoint analysis. A shopping mall intercept survey, which was administered by a marketing research firm, assessed consumer preferences for 12 label alternatives produced on Campbell's soup cans to portray nutrition information realistically; 252 of 258 respondents completed the computer interactive interview. Consumers significantly preferred the bar graph format to the bar graph/nutrient density and traditional label formats. Consumers considered the bar graph/nutrient density format to be as useful as the traditional label format. There was a highly significant difference among the three levels of information load; the most information load was preferred regardless of nutrient importance. Consumers significantly preferred nutrition information stated in absolute numbers and percentages vs in absolute numbers only in traditional, or in percentages only expressions. There was a significant difference between consumer preferences for the two types of information order. The findings indicate that consumers clearly preferred the nutrition label that displayed all nutrient values using a bar graph format, offered the most information load, and expressed nutrient values using both absolute numbers and percentages. Consumers also preferred nutrition information rearranged in an order that grouped nutrients that should be consumed in adequate amounts on the top, calories in the middle, and nutrients that should be consumed in lesser amounts on the bottom of the label. 相似文献
3.
Injections of the retrograde fluorescent tracer fast blue in the striatum (STR) and nuclear yellow in the internal segment of the globus pallidus (GPi) in the squirrel monkey (Saimiri sciureus) revealed a nigropallidal projection whose cellular origin was largely distinct from that of the nigrostriatal pathway. Neurons containing the tracer injected in GPi were scattered throughout the substantia nigra-ventral tegmental area complex where they formed approximately 20-25% of the total number of retrogradely labeled cells. Only about 5-10% of all positive neurons were double-labeled after STR-GPi injections. In experiments combining the use of the fluorescent tracer propidium iodide with immunofluorescence, the majority of neurons projecting to GPi displayed tyrosine hydroxylase immunoreactivity. Hence, in addition to their important role at striatal level, midbrain dopaminergic neurons may influence directly the output neurons of the basal ganglia at pallidal level in primates. 相似文献
4.
A 79-year-old man was referred to emergency department for vagueabdominal pain. In the past, the patient had cardiac arrhythmiasnecessitating a pacemaker placement. On admission, the patienthad a normal ausculation and the abdomen examination was unremarkable.Postero-anterior chest radiograph revealed normal cardiac sizeand a small left pleural effusion. 相似文献
5.
J P Lejeune J P Hladky T Dupard M Parent J C Hache J L Christiaens 《Neuro-Chirurgie》1990,36(5):303-307
A 26-year-old patient presented with acute chiasmal syndrome. Computerized Tomography and Magnetic Resonance Imaging demonstrated an intrachiasmal hematoma which was evacuated via a right subfrontal approach. Histological examination revealed an arteriovenous malformation. In 21 similar cases in the literature, surgery generally resulted in the improvement of ophthalmological signs. In 3/4 of the cases, histology identified a subjacent lesion (arteriovenous malformation, cavernoma, venous angioma, glioma). 相似文献
6.
E. LeGuern R. Gouider D. Mabin S. Tardieu Bs N. Birouk P. Parent P. Bouche A. Brice 《Annals of neurology》1997,41(1):104-108
Charcot-Marie-Tooth type 1A disease is an inherited sensorimotor neuropathy that is most often associated with a duplication of chromosome 17p11.2. This region contains the gene of the peripheral myelin protein 22 (PMP22), which is responsible by a gene dosage effect for the Charcot-Marie-Tooth type 1A phenotype with 17p11.2 duplication. We performed a clinical, electrophysiological, and genetic study of a consanguinous Charcot-marie-Tooth type 1A family with 4 affected siblings, 3 of whom were homozygous for the 17p11.2 duplication, the other a heterozygote. Comparison of phenotypes showed that the severity of the disease was more severely affected than the heterozygous sibling who was pausiymptomatic. These results suggest that the severity of the disease is not determined solely by the number of copies of the PMP22 gene. 相似文献
7.
Summary Obturator hernias comprise a rare group of abdominal hernias. They are often diagnosed when the small bowel has become obstructed
and the patients are operated on without the causes of the obstruction being known. Although many techniques for closure of
the defect are available, there is no agreement at the present time as to which is the procedure of choice. 相似文献
8.
Small injections of two highly sensitive anterograde tracers, Phaseolus vulgaris-leucoagglutinin (PHA-L) and biocytin, into the striatum and the subthalamic nucleus of squirrel monkeys (Saimiri sciureus) have revealed a high degree of convergence of striatal and subthalamic fibers upon single pallidal cells. Both afferent systems formed highly complex band-like patterns that were largely in register with one another. At single cell level, the somata of pallidal neurons were closely surrounded by subthalamic terminal varicosities, whereas the dendrites were entwined mostly by striatal fibers. Typically, a subthalamopallidal fiber coursed in a caudorostral direction and arborized according to a uniform pattern along its trajectory in the pallidum. Numerous thin and markedly varicose axon collaterals detached themselves at right angle from the main subthalamopallidal fiber. These highly branched collaterals were mostly oriented along the mediolateral plane and entwined rather loosely the dendrites but surrounded very closely the somata of pallidal neurons. In contrast, a striatopallidal fiber travelled in a rostrocaudal direction. Its initial segment made only en passant contacts with pallidal cell bodies, whereas its distal end closely entwined the dendrites of pallidal neurons, forming arrangements similar to 'woolly' type fibers. These results suggest that a single subthalamic fiber may influence a rather large collection of pallidal neurons in a similar fashion, compared to the striatal input which appears to exert a more specific control upon selected sets of the same pallidal neurons. 相似文献
9.
The tryptophan metabolite quinolinic acid (QUIN) was injected unilaterally into rat cerebral cortex or striatum in order to determine whether the neurotoxin would destroy neuropeptide Y (NPY)- and somatostatin (SS)-immunoreactive, and NADPH-diaphorase (NADPH-D)-containing neurons. Following intrastriatal injections of QUIN, NPY and SS immunoreactivity and NADPH-D-activity was absent in the injection core area. In contrast, cortical NPY- and SS-immunoreactive cells and NADPH-D-containing neurons were resistant to QUIN's neurotoxicity. These results suggest that in contrast to striatal neurons, cortical SS- and NPY-containing neurons do not express N-methyl-D-aspartate receptors. 相似文献
10.
Timing of carotid endarterectomy after acute stroke 总被引:2,自引:0,他引:2
J J Piotrowski V M Bernhard J R Rubin K E McIntyre J M Malone F N Parent G C Hunter 《Journal of vascular surgery》1990,11(1):45-51; discussion 51-2
An arbitrary delay of at least 6 weeks before performing carotid endarterectomy after acute stroke has been recommended based on anecdotal reports. This prolonged interval may increase the danger of recurrent neurologic deficit before surgery. From September 1978 to September 1988, carotid endarterectomy was performed on 140 patients at variable intervals after stroke. Eleven patients had temporary stroke, which left 129 patients with neurologic symptoms that persisted for 3 weeks or had a cortical infarct on CT scanning. A prospective therapeutic protocol was applied to 82 patients admitted with acute stroke. They were observed until neurologic recovery reached a plateau, based on clinical observation by a neurologist, before performing angiography and carotid endarterectomy (group I). Forty-seven patients were not seen until after recovery from stroke was established (group II). At initial presentation, the severity of neurologic deficit was classified as mild, moderate, or severe in 31%, 58%, and 11%, respectively. Recovery before operation was registered as complete in 11%, mild residual in 66%, moderate residual in 21%, and severe residual in 2%. Group I patients (n = 82, 64%) were operated on within 6 weeks of stroke and group II (n = 47, 36%) were operated on at varying times after 6 weeks. No significant difference was found in the incidence of cerebrovascular events (1.2% vs 4.2%) and deaths (1.3% vs 2.1%) between groups I and II with respect to the timing of carotid endarterectomy, and no significant difference was found between patients operated on at 2, 4, 6, or more than 6 weeks after stroke.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献