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951.
J.-B. Charrassin C. A. Bost K. Pütz J. Lage T. Dahier T. Zorn Y. Le Maho 《Oecologia》1998,114(2):194-201
For oceanic birds like king penguins, a major constraint is the separation of foraging areas from the breeding colony, largely
because swimming increases foraging costs. However, the relationship between foraging strategy and breeding stage has been
poorly investigated. Using time-depth recorders, we studied the diving behaviour of two groups of king penguins that were
either incubating or brooding chicks at Crozet Islands (Southern Indian Ocean) at the same period of the year. Although birds
with chicks had the highest predicted energy demand, they made foraging trips half as long as incubating birds (6 vs. 14 days)
and modified their time and depth utilisation. Birds with chicks dived deeper during daylight (mean maximum depth of 280 m
vs. 205 m for those incubating). At night, birds with chicks spent twice as much time diving as those incubating, but birds
at both stages never dived beyond 30 m. Movements to greater depths by brooding birds are consistent with the vertical distribution
of myctophid fish which are the main prey. As chick provisioning limits trip duration, it is suggested that it is more efficient
for parents to change their diving patterns rather than to restrict their foraging range.
Received: 23 June 1997 / Accepted: 3 November 1997 相似文献
952.
Glycogen storage disease type II (GSDII) is an autosomal recessive disorder resulting from inherited deficiency of the enzyme
lysosomal acid α-glucosidase. Over 40 different mutations have been described but no large deletions have been previously
identified. We now describe a homozygous large (9-kb) deletion extending from IVS15 to 4 kb downstream of the terminal exon
(exon 20), detected by polymerase chain reaction (PCR)-based methods. The deletion was initially suspected because of failure
to amplify a contiguous group of exons by PCR. We hypothesized an Alu/Alu recombination, based on our prior demonstration by Southern blotting of Alu elements in the regions potentially flanking the deletion. Additional sequence analysis of genomic fragments confirmed the
presence of Alu elements and allowed the design of flanking primers for PCR amplification. Amplification resulted in a smaller than normal
fragment (0.7 vs 10 kb) in homozygosity in the proband and in heterozygosity in her parents. Cloning and sequencing of the
smaller than normal 0.7-kb deletion fragment revealed an Alu/Alu deletion junction. In heterozygosity this deletion would not be detected by currently standard PCR mutation detection methods.
Based on other Alu-mediated deletions, this deletion is likely to be recurrent and should be screened for in all non-consanguineous GSDII patients,
particularly when only one mutation has been identified and none of the 12 single-nucleotide polymorphisms in the deleted
region are heterozygous. These observations also suggest that initial characterization of genes at disease-causing loci should
include a search for Alu and other repetitive elements to facilitate subsequent PCR-based mutation analysis.
Received: 24 August 1998 / Accepted: 13 November 1998 相似文献
953.
Ketterling RP Vielhaber E Li X Drost J Schaid DJ Kasper CK Phillips JA Koerper MA Kim H Sexauer C Gruppo R Ambriz R Paredes R Sommer SS 《Human genetics》1999,105(6):629-640
The factor IX gene (F9) is an advantageous system for analyzing recent spontaneous germline mutation in humans. Herein, the male:female ratio of mutation ("r") in F9 have been estimated by Bayesian analysis from 59 germline origin families. The overall "r" in F9 was estimated at 3.75. The "r"s varied with the type of mutation. The "r"s ranged from 6.65 and 6.10 for transitions at CpG and A:T to G:C transitions at non-CpG dinucleotides, respectively, to 0.57 and 0.42 for microdeletions/microinsertions and large deletions (>1 kb), respectively. The "r" for the two subtypes of non-CpG transitions differed (6.10 for A:T to G:C vs 0.80 for G:C to A:T). Somatic mosaicism was detected in 11% of the 45 origin individuals for whom the causative mutation was visualized directly by genomic sequencing of leukocyte DNA (estimated sensitivity of approximately one part in 20). Four of the five defined somatic mosaics had G:C to A:T transitions at non-CpG dinucleotides, hinting that this mutation subtype may occur commonly early in embryogenesis. The age at conception was analyzed for 41 US Caucasian families in which the age of the origin parent and the year of conception for the first carrier/hemophiliac were available. No evidence for a paternal age effect was seen. However, an advanced maternal age effect was observed (P=0.03) and was particularly prominent for transversions (average of the 79th percentile when maternal age was normalized for the year of conception). This suggests that an increased maternal age results in a higher rate of transmitted mutation, whereas the increased number of mitotic replications associated with advanced paternal age has little, if any, effect on the rate of transmitted mutation. 相似文献
954.
955.
K. Liu M. Kasper Angelika Bierhaus Silke Langer Ingrid Peterson Martin Müller Klaus-Rüdiger Trott 《Histochemistry and cell biology》1997,107(2):159-167
The role of the CD44s adhesion molecule, its epithelial isoforms and its relationship to epidermal proteoglycans such as
syndecan was studied in normal and irradiated mouse skin. In normal mouse skin, only 10% of basal cells are strongly CD44s-immunopositive,
with a cytoplasmic expression pattern. Double-label experiments with the basal cell marker keratin 14 confirmed the epithelial
nature of the strongly CD44s-positive cell type in the basal layer. Some spinous keratinocytes and the majority of the remaining
basal cells exhibited a weak membranous staining pattern. In contrast, the epithelial isoform, CD44v10, was strongly present
in all basal and suprabasal epithelial cells of the epidermis, with a membranous staining pattern. Syndecan was found in the
granular layer of the normal epidermis only. After 1 week of daily irradiation, the entire basal cell layer of the epidermis
expressed CD44s in the membrane, but with a varying degree of staining intensity. This reactivity spread to the upper spinous
layer after 3 weeks of treatment. In hyperproliferative epidermis, there was no difference in the staining patterns between
CD44s and CD44v10. The expression of syndecan switched from the granular layer to the basal and lower spinous layers after
2 weeks of daily irradiation. Immunoreactivity for syndecan was also strongly enhanced in the dermis of irradiated samples.
The results suggest an important role for syndecan and CD44 in proliferative processes during radiation-induced accelerated
repopulation.
Accepted: 30 September 1996 相似文献
956.
957.
M. Kasper G. Haroske D. Schuh M. Müller R. Koslowski K -W. Wenzel K. Sakai 《Histochemistry and cell biology》1994,102(5):345-352
The colocalization of surfactant protein A (SP-A) and the alveolar macrophage markers ED1 and RM-1, as well as various lectins of the N-acetyl-galactosamine group [Maclura pomifera lectin (MPA), Dolichos biflorus lectin (DBA), soybean agglutinin (SBA)] and of the mannose group [Canavalia ensiformis lectin (ConA), Galanthus nivalis lectin (GNA)] was studied in normal and fibrotic rat lung tissues. In normal tissue, SP-A was located preferentially in the alveolar macrophage subpopulation lacking specific binding sites for lectins of the N-acetylgalactosamine group (DBA and SBA), although 50% of MPA-binding macrophages contained SP-A. The ED1-positive cells were SP-A-negative, whereas SP-A uptake could be detected among the RM-1 immunoreactive as well as the ConA and GNA binding macrophages. In fibrotic lung tissue, however, a small number of .DBA and SBA binding macrophages contained SP-A and the percentage of GNA and ConA binding alveolar macrophages exhibiting SP-A immunoreactivity was reduced. Additionally, the number of ED1+/SP-A+ macrophages was found to be increased. Immunoelectron microscopy revealed accumulation of SP-A in the extracellular space. The differing SP-A content in different alveolar macrophage subpopulations suggests a more complex mechanism of uptake and degradation of surfactant proteins in normal and pathological conditions, which cannot simply be explained by the glycoconjugate pattern on the surface of alveolar macrophages. 相似文献
958.
Susan Van Noorden Philipp Heitz Marlis Kasper A. G. E. Pearse 《Histochemistry and cell biology》1977,52(4):329-340
Summary Epidermal Growth Factor (EGF) has been localised by immunostaining to granules of the convoluted duct cells of the submaxillary glands of mice. Improved techniques of freeze drying and formaldehyde vapour fixation have resulted in a light microscopical localisation sharper than was achieved by previous methods. EGF has also been identified by electron immunocytochemistry using the unlabelled antibody enzyme method. EGF is present in greater quantities in male mice than in female mice but in pregnant females the level of EGF in the submaxillary gland is equal to that of the male. It declines gradually during the three weeks of lactation. In view of the chemical similarity between mouse EGF and human Urogastrone these improved methods of identification may be useful in the localisation of the human substance.This work was presented at the first Symposium on Gastrointestinal Hormones held at Asilomar, California, USA in October 1976 相似文献
959.
At a recent ECVAM workshop considering ways to reduce the frequency of irrelevant positive results in mammalian cell genotoxicity tests [D. Kirkland, S. Pfuhler, D. Tweats, M. Aardema, R. Corvi, F. Darroudi, A. Elhajouji, H.-R. Glatt, P. Hastwell, M. Hayashi, P. Kasper, S. Kirchner, A. Lynch, D. Marzin, D. Maurici, J.-R. Meunier, L. Müller, G. Nohynek, J. Parry, E. Parry, V. Thybaud, R. Tice, J. van Benthem, P. Vanparys, P. White, How to reduce false positive results when undertaking in vitro genotoxicity testing and thus avoid unnecessary followup animal tests: Report of an ECVAM Workshop, Mutat. Res. 628 (2007) 31-55], recommendations for improvements/modifications to existing tests, and suggestions for new assays were made. Following on from this, it was important to identify chemicals that could be used in the evaluation of modified or new assays. An expert panel was therefore convened and recommendations made for chemicals to fit three different sets of characteristics, namely: This paper therefore contains these three recommended lists of chemicals and describes how these should be used for any test-evaluation programme. 相似文献
960.