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81.
82.
Donald H. Burke Linda A. Raubeson Marie Alberti John E. Hearst Elizabeth T. Jordan Susan A. Kirch Angela E. C. Valinski David S. Conant Diana B. Stein 《Plant Systematics and Evolution》1993,187(1-4):89-102
We examinedchlL (frxC) gene evolution using several approaches. Sequences from the chloroplast genome of the fernPolystichum acrostichoides and from the cyanobacteriumSynechococcus sp. 7002 were determined and found to be highly conserved. A complete physical map of the fern chloroplast genome and partial maps of other vascular plant taxa show thatchlL is located primarily in the small single copy region as inMarchantia polymorpha. A survey of a wide variety of non-angiospermous vascular plant DNAs shows thatchlL is widely distributed but has been lost in the pteridophytePsilotum and (presumably independently) within the Gnetalean gymnosperms.The namefrxC was originally used to denote a gene encoding a product with probable Fe : S cluster binding activity. This activity was postulated due to the amino acid sequence similarity between this product and the Fe : S-binding nitrogenase iron proteinnifH. Fe : S-binding is a property shared by ferredoxins, which are denoted by the prefix frx. However, this gene does not encode a ferredoxin. It is much larger than any known ferredoxin, it binds its Fe : S cluster between two halves of a homodimer (Fujita & al. 1989,Burke & al. 1993 a, c) instead of within a single subunit, and it lacks the pattern of clustered cysteines present in all ferredoxins (Meyer 1988). Therefore, we use the namechlL to recognize the sequence and functional similarities to the bacterial PChlide reductase subunit,bchL. Similar usage has been adopted for this (Suzuki & Bauer 1992) and other (Choquet & al. 1992,Burke & al. 1993b) PChlide reductase subunits. 相似文献
83.
Molecular cytological evidence for gradual telomere synthesis at the broken chromosome ends in wheat
Hisashi Tsujimoto 《Journal of plant research》1993,106(3):239-244
Telomere formation of the normal and broken chromosomes of common wheat,Triticum aestivum, was investigated byin situ hybridization using the biotin-labeled probe of telomere repetitive sequences (pAtT4) ofArabidopsis thaliana with subsequent amplification by an antibody. After double and triple amplification, prominent signals appeared at all the
telomeric regions of the normal chromosomes.
Prominent signals also emerged at the broken ends of the telocentric and deletion chromosomes that had passed through more
than one generation since the appearance. However, broken ends that had passed through only the stages of gametogenesis, fertilization,
embryogenesis and root development did not show complete signals such as found in normal telomeres. These findings indicate
that a certain time or stage is required for synthesis of the telomeric repetitive sequences with a complete length. Nevertheless,
because the broken ends without complete telomere sequences were also healed, restoration of the normal complement of telomere
sequences is not necessary for healing of broken ends. 相似文献
84.
Summary A new method, a restrained Monte Carlo (rMC) calculation, is demonstrated for generating high-resolution structures of DNA oligonucleotides in solution from interproton distance restraints and bounds derived from complete relaxation matrix analysis of two-dimensional nuclear Overhauser effect (NOE) spectral peak intensities. As in the case of restrained molecular dynamics (rMD) refinement of structures, the experimental distance restraints and bounds are incorporated as a pseudo-energy term (or penalty function) into the mathematical expression for the molecular energy. However, the use of generalized helical parameters, rather than Cartesian coordinates, to define DNA conformation increases efficiency by decreasing by an order of magnitude the number of parameters needed to describe a conformation and by simplifying the potential energy profile. The Metropolis Monte Carlo method is employed to simulate an annealing process. The rMC method was applied to experimental 2D NOE data from the octamer duplex d(GTA-TAATG)·d(CATTATAC). Using starting structures from different locations in conformational space (e.g. A-DNA and B-DNA), the rMC calculations readily converged, with a root-mean-square deviation (RMSD) of <0.3 Å between structures generated using different protocols and starting structures. Theoretical 2D NOE peak intensities were calculated for the rMC-generated structures using the complete relaxation matrix program CORMA, enabling a comparison with experimental intensities via residual indices. Simulation of the vicinal proton coupling constants was carried out for the structures generated, enabling a comparison with the experimental deoxyribose ring coupling constants, which were not utilized in the structure determination in the case of the rMC simulations. Agreement with experimental 2D NOE and scalar coupling data was good in all cases. The rMC structures are quite similar to that refined by a traditional restrained MD approach (RMSD<0.5 Å) despite the different force fields used and despite the fact that MD refinement was conducted with additional restraints imposed on the endocyclic torsion angles of deoxyriboses. The computational time required for the rMC and rMD calculations is about the same. A comparison of structural parameters is made and some limitations of both methods are discussed with regard to the average nature of the experimental restraints used in the refinement.Abbreviations MC
Monte Carlo
- rMC
restrained Monte Carlo
- MD
molecular dynamics
- rMD
restrained molecular dynamics
- DG
distance geometry
- EM
energy minimization
- 2D NOE
two-dimensional nuclear Overhauser effect
- DQF-COSY
double-quantum-filtered correlation spectroscopy
- RMSD
root-mean-square deviation
To whom correspondence should be addressed. 相似文献
85.
Douglas E Bassett Jr Munira A Basrai Carla Connelly Katherine M Hyland Katsumi Kitagawa Melanie L Mayer Dwight M Morrow Andrew M Page Vicente A Resto Robert V Skibbens Philip Hieter 《Current opinion in genetics & development》1996,6(6):763-766
The completion of the genome sequence of the budding yeast Saccharomyces cerevisiae marks the dawn of an exciting new era in eukaryotic biology that will bring with it a new understanding of yeast, other model organisms, and human beings. This body of sequence data benefits yeast researchers by obviating the need for piecemeal sequencing of genes, and allows researchers working with other organisms to tap into experimental advantages inherent in the yeast system and learn from functionally characterized yeast gene products which are their proteins of interest. In addition, the yeast post-genome sequence era is serving as a testing ground for powerful new technologies, and proven experimental approaches are being applied for the first time in a comprehensive fashion on a complete eukaryotic gene repertoire. 相似文献
86.
87.
Pollen allergens interact with the human immune system and the resulting IgE antibodies provide specific probes for their
identification and characterisation. In one case, grass allergenic proteins are expressed late in pollen development coincident
with the laying down of reserves. Sequence similarity of allergens has indicated possible functions for some allergens. The
major birch pollen allergen shows sequence similarity with pathogenesis-related proteins, which form a secondary response
in plant host-pathogen interactions and show anti-microbial activity. Some allergens of unknown function are cysteine-rich
proteins, while some others have cysteine-rich regions; for example, the major allergen from rye-grass pollen, Lol p 1, has
a cysteine-rich N-terminal region, while at the C-terminal region four tryptophan residues together with tyrosine and phenylalanine
residues resemble those of cellulose- or sugar-binding domains of other proteins. Several pollen allergens show sequence similarity
to cell wall-associated enzymes, while others show hydrolytic enzyme activity often associated with cell walls. 相似文献
88.
栝楼核糖核酸酶(RNase TCS)对U碱基具有高度的专一性,在无脲、pH3.5、50℃时,它几乎都在-NP ↓ U-处裂解RNA.它与RNase T1,U2和有限的碱水解一起,可用于直接的酶法RNA序列分析. 相似文献
89.
The Nucleotide Sequence of Human Acylamino Acid-Releasing Enzyme 总被引:3,自引:0,他引:3
Mitta Masanori; Ohnogi Hiroshi; Mizutani Shigetoshi; Sakiyama Fumio; Kato Ikunoshin; Tsunasawa Susumu 《DNA research》1996,3(1):31-35
The nucleotide sequence of a cDNA coding for the human acylaminoacid-releasing enzyme (AARE, also known as acylpeptide hydrolase)[EC 3.4.19.1] subunit has been determined. The amino acid sequenceof human AARE subunit deduced from its cDNA nucleotide sequenceshowed a high degree of identity (91.5%) with both the correspondingproteins from the pig and the rat. The AARE cDNA shows 99.2%identity with a 3.3 kb cDNA transcribed from a locus (DNF15S2)on the short arm of human chromosome 3, whose deletion is associatedwith small cell lung cancer, taking into consideration thatthe sequence of the 3.3-kb cDNA previously reported was causedby misreading. 相似文献
90.
The concept of nucleic acid sequence base alternations is presented.The number of base alterations for the sequences of differentlength is established. The definition of "enlarged similarity"of nucleic acids sequences on the basis of sequence base alterationsis introduced. Mutual information between sequences is usedas a quantitative measure of enlarged similarity for two comparedsequences. The method of mutual information calculation is developedconsidering the correlation of bases in compared sequences.The definitions of correlated similarity and evolution similaritybetween compared sequences are given. Results of the use ofenlarged similarity approach for DNA sequences analysis arediscussed. 相似文献