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51.
Optical and physical properties of wet-spun films of Na-hyaluronate. Evidence of a phase transition.
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The refractive indices, water content, and volume of wet-spun films of Na-hyaluronate have been measured as a function of relative humidity (rh). These data are used with the Lorentz-Lorenz formula to determine the optical polarizabilities of Na-hyaluronate parallel and perpendicular to the helical axis. The analysis reveals a drop in the optical polarizabilities of approximately 20% between 80 and 88% rh, indicating a phase transition. 相似文献
52.
Molecular evolution of rodent insulins 总被引:1,自引:0,他引:1
Several trees of amino acid sequences of rodent insulins were derived with
the maximum-parsimony procedure. Possible orthologous and paralogous
relationships were investigated. Except for a recent gene duplication in
the ancestor of rat and mouse, there are no strong arguments for other
paralogous relationships. Therefore, a tree in agreement with other
biological data is the most reasonable one. According to this tree, the
capacity to form zinc-binding hexamers was lost once in the ancestor of the
hystricomorph rodents, followed by moderately increased evolutionary rates
in the lineages to African porcupine and chinchilla but highly increased
rates in at least three independent lines to other taxa of this suborder:
guinea pig, cuis, and Octodontoidea (coypu and casiragua).
相似文献
53.
From 1976 to 1980, 1034 infants with birth weights of 500-2000 g were cared for in the neonatal medical unit; 724 were discharged. Twenty (2.8%) subsequently died and 654 (90.3%) were followed up at a median age of 3 years 3 months. Fifty five (7.6%) survivors had major neurodevelopmental handicaps not attributable to congenital anomalies. Increasing prevalence of major handicap was found with decreasing birth weight and gestation. Children with birth weights of less than 1251 g had a higher incidence of all major disabilities. Handicapped children with a birth weight less than 1251 g were more likely to have blindness, deafness, multiple disabilities, and more severe cerebral palsy. There were 146 (20.2%) children with minor disabilities: neurological impairments (n = 11), borderline results on psychometric testing (n = 18), visual impairments (n = 52), hearing impairments (n = 40), and speech impairments (n = 71). Children weighing less than 1251 g at birth had a higher incidence of minor visual and hearing impairments. In 389 children the mean Griffiths quotient was 101.6 (SD 17.2) (range 50-147), and 158 children had a mean Wechsler preschool and primary intelligence quotient of 101.8 (13.2) (range 56-127): these quotients did not vary with birth weight or gestation but did vary with socioeconomic group, schooling, and family structure. During the study period an improving prognosis in terms of both survival and handicap was observed in children weighing less than 1251 g at birth. 相似文献
54.
Jason J. Jones Jaime E. Settle Robert M. Bond Christopher J. Fariss Cameron Marlow James H. Fowler 《PloS one》2013,8(1)
Some social connections are stronger than others. People have not only friends, but also best friends. Social scientists have long recognized this characteristic of social connections and researchers frequently use the term tie strength to refer to this concept. We used online interaction data (specifically, Facebook interactions) to successfully identify real-world strong ties. Ground truth was established by asking users themselves to name their closest friends in real life. We found the frequency of online interaction was diagnostic of strong ties, and interaction frequency was much more useful diagnostically than were attributes of the user or the user’s friends. More private communications (messages) were not necessarily more informative than public communications (comments, wall posts, and other interactions). 相似文献
55.
Reef-building scleractinian corals widely engage in symbiotic relationships with Symbiodinium dinoflagellates (zooxanthellae), which reside inside cells of the gastrodermis. In most cases, sexually produced larvae acquire their symbionts from the environment in the early developmental stages preceding settlement; however, some scleractinian corals maternally "seed" their oocytes with symbionts, and these symbionts are reported to be restricted to the gastrodermis at the time of its formation (gastrulation). A precise mechanism for how Symbiodinium are translocated to endoderm in these seeded species was previously unknown. In order to examine the process of endoderm formation and Symbiodinium localization during gastrulation, we have examined two species of "robust" clade scleractinians: Fungia scutaria (nonseeded) and Pocillopora meandrina (maternally seeded). We determined that both species, independent of whether or not they are seeded, undergo a "nutritive" stage before gastrulation, wherein lipid-rich cells (F. scutaria) or membrane-bound cellular fragments (P. meandrina) are passed to the blastocoel where they are subsequently taken up by the definitive endoderm. This emergent property of anthozoan development has been co-opted to facilitate the movement of Symbiodinium to the blastocoel (future site of endoderm), in the seeded species, where they are later phagocytosed by the newly formed definitive endoderm. Additionally, both species of robust clade scleractinians examined gastrulate by way of invagination, as do the majority of anthozoans. This invagination differs from the prawn chip-type gastrulation seen in the complex clade corals and provides evidence for a possible linkage between gastrulation type and phylogenetic history. 相似文献
56.
Jaiswal JK Marlow G Summerill G Mahjneh I Mueller S Hill M Miyake K Haase H Anderson LV Richard I Kiuru-Enari S McNeil PL Simon SM Bashir R 《Traffic (Copenhagen, Denmark)》2007,8(1):77-88
Two autosomal recessive muscle diseases, limb girdle muscular dystrophy type 2B (LGMD2B) and Miyoshi myopathy (MM), are caused by mutations in the dysferlin gene. These mutations result in poor ability to repair cell membrane damage, which is suggested to be the cause for this disease. However, many patients who share clinical features with MM-type muscular dystrophy do not carry mutations in dysferlin gene. To understand the basis of MM that is not due to mutations in dysferlin gene, we analyzed cells from patients in one such family. In these patients, we found no defects in several potential candidates - annexin A2, caveolin-3, myoferlin and the MMD2 locus on chromosome 10p. Similar to dysferlinopathy, these cells also exhibit membrane repair defects and the severity of the defect correlated with severity of their disease. However, unlike dysferlinopathy, none of the conventional membrane repair pathways are defective in these patient cells. These results add to the existing evidence that cell membrane repair defect may be responsible for MM-type muscular dystrophy and indicate that a previously unsuspected genetic lesion that affects cell membrane repair pathway is responsible for the disease in the non-dysferlin MM patients. 相似文献
57.
58.
K. E. Nussear C. R. Tracy P. A. Medica D. S. Wilson R. W. Marlow P. S. Corn 《The Journal of wildlife management》2012,76(7):1341-1353
We translocated 120 Agassiz's desert tortoises to 5 sites in Nevada and Utah to evaluate the effects of translocation on tortoise survivorship, reproduction, and habitat use. Translocation sites included several elevations, and extended to sites with vegetation assemblages not typically associated with desert tortoises in order to explore the possibility of moving animals to upper elevation areas. We measured survivorship, reproduction, and movements of translocated and resident animals at each site. Survivorship was not significantly different between translocated and resident animals within and among sites, and survivorship was greater overall during non-drought years. The number of eggs produced by tortoises was similar for translocated and resident females, but differed among sites. Animals translocated to atypical habitat generally moved until they reached vegetation communities more typical of desert tortoise habitat. Even within typical tortoise habitat, tortoises tended to move greater distances in the first year after translocation than did residents, but their movements in the second or third year after translocation were indistinguishable from those of resident tortoises. Our data show that tortoises translocated into typical Mojave desert scrub habitats perform well; however, the large first-year movements of translocated tortoises have important management implications. Projects that employ translocations must consider how much area will be needed to contain translocated tortoises and whether roads need fencing to prevent the loss of animals. © 2012 The Wildlife Society. 相似文献
59.
60.
Victor van der Meer Henk F van Stel Moira J Bakker Albert C Roldaan Willem JJ Assendelft Peter J Sterk Klaus F Rabe Jacob K Sont 《Respiratory research》2010,11(1):74