全文获取类型
收费全文 | 443篇 |
免费 | 57篇 |
国内免费 | 4篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 17篇 |
2019年 | 22篇 |
2018年 | 13篇 |
2017年 | 20篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 22篇 |
2012年 | 26篇 |
2011年 | 27篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 20篇 |
2006年 | 25篇 |
2005年 | 23篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有504条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
An epithermal neutron activation method is used to determine the concentration of mineral elements in human dental enamel.
A large number (252) of samples from ancient and modern origins are analyzed. The analytical results are mathematically processed
using a statistical multivariant method. This allows to differentiate deciduous from permanent teeth and decayed from sound
enamel. It is also possible to distinguish the teeth coming from two different necropoles. The origin and the localization
of determined elements in the mineralized part, or in the aqueous-organic part, of enamel is suggested. Their role, as witnessed
in the physiopathological phenomena of dental enamel, is discussed. 相似文献
5.
The size relationship between the crown area of the lower canines (Cs), third (P3s) and fourth premolars (P4s), and first
molars (M1s) in hominids is examined by means of the regression analysis. The lower P3 seem to be under the influence of those
factors that control both the size of the anterior and posterior teeth, and the P4:P3 size ratio is related to the relative
size of the anterior and posterior dentitions. So, the P4>P3 sequence is associated with the megadontia and hipermegadontia
of the posterior teeth, whereas the expansion of the anterior teeth produces the P3>P4 sequence. We consider the P4:P3 size
ratio as an excellent indicator of the taxonomic and philogenetic status of fossil hominids. 相似文献
6.
Occurrence of heavy metals,sodium, calcium,and potassium in human hair,teeth, and nails 总被引:1,自引:0,他引:1
Barbara Nowak 《Biological trace element research》1996,52(1):11-22
Heavy metals in biological samples: nails, teeth, and hair were examined during 1991–1993. Investigations of biological samples
(hairn=249 samples, teethn=145, nailsn=80 samples) were provided for inhabitants of selected towns in Beskid Śląski. The towns are small mountain towns in southern
Poland: Wista, Szczyrk, Istebna, Koniaków, and Jaworzynka. The analysis of ANOVA and MANOVA variances were used for biological
samples in the context of age, sex, and type of samples for 12 elements (Pb, Cd, Cr, Zn, Fe, Cu, Mn, Ni, Co, Ca, Na, and K).
The matrix correlation and cluster analysis were applied to explain the behavior of metals in human hair, teeth, and nails. 相似文献
7.
Katherine Coffing Craig Feibel Meave Leakey Alan Walker 《American journal of physical anthropology》1994,93(1):55-65
A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis. © 1994 Wiley-Liss, Inc. 相似文献
8.
J. H. Van Wyk 《Biotechnic & histochemistry》1993,68(5):290-301
Two fixation fluids, two fixation techniques and two embedding methods were investigated for their effects on the quality of sections of teeth for pulpal response to filling materials to improve evaluation of pulpal responses. Sections from 32 baboon teeth were prepared, half with experimental cavities and half without, using either 10% formaldehyde or 4% glutaraldehyde, longitudinal tooth splitting or removal of the tooth apex, and paraffin or K plast resin embedding; decalcification in a formic acid mixture was a constant throughout. Histometric analysis showed that paraffin embedding produced less shrinkage than the K Plast resin embedding although the difference was not statistically significant. Six parameters of separation at the pu1p:dentine interface were studied: embedding, fixative, presence or absence of a cavity, cutting technique and individual animal tooth type. Statistical investigation revealed that fixative, cutting technique, and fixative and cutting technique combined had significant influences on the separation artifact. Of the combinations tested the choice of embedding method depends on which of the two artifacts, shrinkage or separation, is more adverse in the opinion of the investigator. Four percent glutaraldehyde together with the longitudinal split technique of fixation. processed by either K Plast resin embedding or paraffin embedding produced satisfactory pulpal sections. 相似文献
9.
Jos M. Bermúdez De Castro M. Elena Nicolas 《American journal of physical anthropology》1995,96(4):335-356
In order to reassess previous hypotheses concerning dental size reduction of the posterior teeth during Pleistocene human evolution, current fossil dental evidence is examined. This evidence includes the large sample of hominid teeth found in recent excavations (1984–1993) in the Sima de los Huesos Middle Pleistocene cave site of the Sierra de Atapuerca (Burgos, Spain). The lower fourth premolars and molars of the Atapuerca hominids, probably older than 300 Kyr, have dimensions similar to those of modern humans. Further, these hominids share the derived state of other features of the posterior teeth with modern humans, such as a similar relative molar size and frequent absence of the hypoconulid, thus suggesting a possible case of parallelism. We believe that dietary changes allowed size reduction of the posterior teeth during the Middle Pleistocene, and the present evidence suggests that the selective pressures that operated on the size variability of these teeth were less restrictive than what is assumed by previous models of dental reduction. Thus, the causal relationship between tooth size decrease and changes in food-preparation techniques during the Pleistocene should be reconsidered. Moreover, the present evidence indicates that the differential reduction of the molars cannot be explained in terms of restriction of available growth space. The molar crown area measurements of a modern human sample were also investigated. The results of this study, as well as previous similar analyses, suggest that a decrease of the rate of cell proliferation, which affected the later-forming crown regions to a greater extent, may be the biological process responsible for the general and differential dental size reduction that occurred during human evolution. © 1995 Wiley-Liss, Inc. 相似文献
10.
Summary The mandibular glands of Kalotermes were examined in different castes. They showed sexual dimorphism in the soldiers and primary reproductives. Moreover, in female soldiers and queens, mandibular gland cells contained numerous crystalline structures of mitochondrial origin. The role of these glands (secretion of saliva or pheromone) is discussed.
Résumé Les glandes mandibulaires de Calotermes sont étudiées dans les différentes castes. Elles présentent un dimorphisme sexuel chez les soldats et les sexués. Après la mue imaginale, les cellules glandulaires ont toujours une activité sécrétrice. De plus, chez les soldats femelles et les reines, elles contiennent de nombreuses formations cristallines d'origine mitochondriale. Le rôle de ces glandes (sécrétion de salive ou de phéromone) est discuté.相似文献