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排序方式: 共有10000条查询结果,搜索用时 171 毫秒
971.
972.
A human homologue of the Drosophila melanogaster diaphanous gene is disrupted in a patient with premature ovarian failure: evidence for conserved function in oogenesis and implications for human sterility. 总被引:7,自引:0,他引:7 下载免费PDF全文
S Bione C Sala C Manzini G Arrigo O Zuffardi S Banfi G Borsani P Jonveaux C Philippe M Zuccotti A Ballabio D Toniolo 《American journal of human genetics》1998,62(3):533-541
Premature ovarian failure (POF) is a defect of ovarian development and is characterized by primary or secondary amenorrhea, with elevated levels of serum gonadotropins, or by early menopause. The disorder has been attributed to various causes, including rearrangements of a large "critical region" in the long arm of the X chromosome. Here we report identification, in a family with POF, of a gene that is disrupted by a breakpoint. The gene is the human homologue of the Drosophila melanogaster diaphanous gene; mutated alleles of this gene affect spermatogenesis or oogenesis and lead to sterility. The protein (DIA) encoded by the human gene (DIA) is the first human member of the growing FH1/FH2 protein family. Members of this protein family affect cytokinesis and other actin-mediated morphogenetic processes that are required in early steps of development. We propose that the human DIA gene is one of the genes responsible for POF and that it affects the cell divisions that lead to ovarian follicle formation. 相似文献
973.
974.
975.
Denis Bugnon Gilles Potel Jocelyne Caillon Denis Baron Henri B. Drugeon Philippe Feigel Marie F. Kergueris 《Bulletin of mathematical biology》1998,60(3):545-567
The evaluation of drugs in vivo is often based on experimental models using small animals such as mice, rats and rabbits. However, these models could be
improved to correspond more closely to the human situation if the pharmacokinetics of the drugs tested in animals were similar
to that observed in humans. The use of a computer-controlled pump allowing an adequate flow of tobramycin and amikacin to
be infused into rabbits enabled us to simulate the human pharmacokinetics of these antibiotics in vivo in this study. The function defining the rate of infusion required to perform the simulation of an intravenous bolus was
first determined generally and symbolically for linear pharmacokinetic models independently from the number of compartments
involved. The practical simulation of a decreasing monoexponential serum profile with a half-life of 2 h (one-compartment
model for the human pharmacokinetics of aminoglycosides) was then studied for tobramycin and amikacin on the basis of a two-compartment
model in the animal. The kinetics obtained had an apparent elimination half-life of 1.97 and 1.86 h, respectively. Linearity
of the semilogarithmic regressions of the profiles obtained was quite sound. Finally, an a posteriori analysis of the pharmacokinetic model and its parameters is proposed on the basis of the results obtained after simulation. 相似文献
976.
Véronique Zupan Joanna M. Hill Douglas E. Brenneman †Illana Gozes ‡Mati Fridkin §Patrick Robberecht Philippe Evrard Pierre Gressens 《Journal of neurochemistry》1998,70(5):2165-2173
Abstract: At the end of neuronal migration, the neopallial germinative zone produces glial cells destined to colonize the upper layers of neocortex. High densities of binding sites for vasoactive intestinal peptide (VIP) have been found in the rodent germinative zone just after completion of neuronal migration, suggesting a possible role of VIP in neocortical astrocytogenesis. In the present study, administration of a VIP antagonist at embryonic days 17 and 18 to pregnant mice was followed by a dramatic depletion of astrocytes in the upper cortical layer of the offspring. The depletion of astrocytes was dose-dependent, with a 42% reduction in the density of astrocytes observed with 50 µg of antagonist. The antagonist effect was reversed by cotreatment with VIP or pituitary adenylate cyclase-activating polypeptide (PACAP), suggesting the involvement of a receptor common to these two neuropeptides. VIP antagonist-induced inhibition of astrocytogenesis was also blocked by Ro 25-1553, a long-acting cyclic VIP analogue selective for the PACAP II VIP2 receptor subclass. Our results demonstrate that VIP and/or PACAP play a crucial physiological role in neocortical astrocytogenesis, possibly through interaction with PACAP II VIP2 receptors. 相似文献
977.
Adam Clark Arcadi Daniel Robert Christophe Boesch 《Primates; journal of primatology》1998,39(4):505-518
Wild chimpanzees (Pan troglodytes) generate low-frequency sounds that are audible to humans from a distance of at least 1 km away by hitting the buttresses of trees with their hands and feet. This buttress drumming occurs in discrete bouts of rapidly delivered beats that usually accompany “pant hoots,” the species-specific long-distance vocalization. Individual differences in male chimpanzee (P.t. verus) drumming were investigated during a 6-month field study in the Taï National Park, Ivory Coast. Analysis of drumming bouts recorded from six adult males revealed significant differences between individuals in three acoustic features: (1) mean duration of inter-beat interval; (2) mean number of beats per bout; and (3) mean bout duration. Preliminary analysis indicated that individuals differ in their tendency to deliver drum beats in temporally close pairs separated by longer interbeat intervals. Qualitative examination also suggested that individuals may differ in the temporal integration of drumming into the pant hoot vocalization. These results suggest that there may be acoustic cues available for chimpanzees to recognize unseen males by their drumming performances alone. Drumming by Taï chimpanzees was also compared to drumming by chimpanzees (P.t. schweinfurthii) from the Kanyawara study group in Kibale National Park. Uganda. The Kanyawara chimpanzees appeared to drum more often without vocalizing than did the Taï chimpanzees. When they did drum and vocalize together, the Kanyawara chimpanzees appeared to integrate their drumming later into the associated pant hoots than did the Taï chimpanzees. These results suggest the possibility that interpopulation variation exists in chimpanzee buttress drumming. 相似文献
978.
979.
980.
L. Ameye Philippe Compère Jean Dille Philippe Dubois 《Histochemistry and cell biology》1998,110(3):285-294
The ultrastructure and cytochemistry of skeleton formation sites prior to mineralization are described for the first time
in echinoderms. These early sites are intracellular vacuoles located in syncytial pseudopodia of skeleteton-forming cells.
They contain a mineralization organic matrix, which shows a calcium-binding ability and is framed in a tridimensional structure
made of concentric layers bridged by radial threads. This organic matrix presents repetitive structures which could be implicated
in mineralization control. Both the tridimensional organization of the organic matrix and its framing, before mineralization
starts, question the current theories which suggest that the echinoderm organic matrix is soluble at the onset of mineralization
and adsorbs on the forming crystal.
Accepted: 19 March 1998 相似文献