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91.
This is a comparative study of uptake of trimethoprim from 1) fresh water, 2) salt water after 7 days of adaption and 3) salt water without previous adaptation. The rate and extent of absorption were found to vary significantly. The salt water adapted group reached a plasma concentration of approx. 1 µg/ml after 10 h, the unadapted salt water group after 24 to 48 h and the fresh water group did not reach this concentration. The results are discussed in relation to the non-ionic diffusion theory and to the alterations taking place in euryhaline species of fish during adaptation to salt water. 相似文献
92.
Andresen Ø. Amrud J. Grøholt L. E. Heiland G. Schie K. A. Sylliås G. A. 《Acta veterinaria Scandinavica》1980,21(1):108-112
Total thyroxine (TT4) and free thyroxine index (FT4I) were measured in peripheral plasma of cows. The samples were collected at the time of insemination from 66 cows showing pronounced signs of the heat and from 56 cows showing weak or silent heat. Neither TT4 or FT4I in plasma differed significantly between the two categories of oestrous cows. 相似文献
93.
14C-labeled extracellular organic carbon (EOC) released by the phytoplankton in a Danish Estuary was shown immediately to form particles (>0.2m) when the products were added to a natural water sample. About 14%–20% of the added activity could be recovered as particles. Any bacterial assimilation of the extracellular products was thus masked. The abiotic origin of the particulate EOC was verified, and it was shown that the particle formation was due to some factors present in the estuarine water with a nominal diameter >0.2m. Precaution must be taken to avoid misinterpretations in studies concerning carbon flow from algae to bacteria. 相似文献
94.
95.
Paula Branefors-Helander Björn Classon Lennart Kenne Bengt Lindberg 《Carbohydrate research》1979,76(1):197-202
The structure of the capsular antigen from Haemophilus influenza type c has been investigated, n.m.r. spectroscopy being the principal method used. It is concluded that the antigen is composed of repeating-units having the following structure: O-Acetyl groups are present in ~90% of the repeating-units. 相似文献
96.
97.
98.
Aldo Spanjaard Ronak Shah Daniël de
Groot Olimpia Alessandra Buoninfante Ben Morris Cor Lieftink Colin Pritchard Lisa
M Zürcher Shirley Ormel Joyce J I Catsman Renske de
Korte-Grimmerink Bjrn Siteur Natalie Proost Terry Boadum Marieke van
de
Ven Ji-Ying Song Maaike Kreft Paul C M van
den
Berk Roderick
L Beijersbergen Heinz Jacobs 《Nucleic acids research》2022,50(13):7420
Crosslink repair depends on the Fanconi anemia pathway and translesion synthesis polymerases that replicate over unhooked crosslinks. Translesion synthesis is regulated via ubiquitination of PCNA, and independently via translesion synthesis polymerase REV1. The division of labor between PCNA-ubiquitination and REV1 in interstrand crosslink repair is unclear. Inhibition of either of these pathways has been proposed as a strategy to increase cytotoxicity of platinating agents in cancer treatment. Here, we defined the importance of PCNA-ubiquitination and REV1 for DNA in mammalian ICL repair. In mice, loss of PCNA-ubiquitination, but not REV1, resulted in germ cell defects and hypersensitivity to cisplatin. Loss of PCNA-ubiquitination, but not REV1 sensitized mammalian cancer cell lines to cisplatin. We identify polymerase Kappa as essential in tolerating DNA damage-induced lesions, in particular cisplatin lesions. Polk-deficient tumors were controlled by cisplatin treatment and it significantly delayed tumor outgrowth and increased overall survival of tumor bearing mice. Our results indicate that PCNA-ubiquitination and REV1 play distinct roles in DNA damage tolerance. Moreover, our results highlight POLK as a critical TLS polymerase in tolerating multiple genotoxic lesions, including cisplatin lesions. The relative frequent loss of Polk in cancers indicates an exploitable vulnerability for precision cancer medicine. 相似文献
99.
Nicolas Rapin Can Kesmir Sune Frankild Morten Nielsen Claus Lundegaard Søren Brunak Ole Lund 《Journal of biological physics》2006,32(3-4):335-353
Over the past decade a number of bioinformatics tools have been developed that use genomic sequences as input to predict to
which parts of a microbe the immune system will react, the so-called epitopes. Many predicted epitopes have later been verified
experimentally, demonstrating the usefulness of such predictions. At the same time, simulation models have been developed
that describe the dynamics of different immune cell populations and their interactions with microbes. These models have been
used to explain experimental findings where timing is of importance, such as the time between administration of a vaccine
and infection with the microbe that the vaccine is intended to protect against. In this paper, we outline a framework for
integration of these two approaches. As an example, we develop a model in which HIV dynamics are correlated with genomics
data. For the first time, the fitness of wild type and mutated virus are assessed by means of a sequence-dependent scoring
matrix, derived from a BLOSUM matrix, that links protein sequences to growth rates of the virus in the mathematical model.
A combined bioinformatics and systems biology approach can lead to a better understanding of immune system-related diseases
where both timing and genomic information are of importance. 相似文献
100.
Structures of mitochondrial bc1 complex have been reported based on four different crystal forms by three different groups. In these structures, the extrinsic domain of the Rieske [2Fe-2S] protein, surprisingly, appeared at three different positions: the "c1" position, where the [2Fe-2S] cluster exists in close proximity to the heme c1; the "b" position, where the [2Fe-2S] cluster exist in close proximity to the cytochrome b; and the "intermediate" position where the [2Fe-2S] cluster exists in-between "c1" and "b" positions. The conformational changes between these three positions can be explained by a combination of two rotations; (1) a rotation of the entire extrinsic domain and (2) a relative rotation between the cluster-binding fold and the base fold within the extrinsic domain. The hydroquinone oxidation and the electron bifurcation mechanism at the Q(P) binding pocket of the bc1 complex is well explained using these conformational changes of the Rieske [2Fe-2S] protein. 相似文献