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51.
Unusual base sequence arrangement in phage phi 29 DNA. 总被引:9,自引:0,他引:9
Susceptibility of Bacillus subtilis phage phi 29 DNA to 34 different restriction endoculceases was determined. Three enzymes, BglI, XbaI and BstEII, were found to cleave phi 29 DNA only once at specific sites. The sites of these single cleavages have been mapped. Thirteen enzymes did not cut phi 29 DNA. phi 29 HindIII DNA fragments inserted into pBR313 plasmid and propagated in Escherichia coli, were resistant to these restriction endonucleases. This result suggests that the insusceptibility is due to the absence of the nucleotide sequences on phi 29 recognized by the enzymes, and not to the presence of modified nucleotides. 相似文献
52.
Koreaki Ito 《Biochemical and biophysical research communications》1978,82(1):99-107
Effects of protease inhibitors on composition of newly synthesized protein were studied by pulse-labeling E. coli cells with [3H]leucine and analyzing the labeled proteins by sodium dodecylsulfate gel electrophoresis. In addition to tosyl-lysine chloromethylketone that had been studied previously, antipain, leupeptin and diisopropyl fluorophosphate all inhibited production of a major outer membrane protein, protein I. Synthesis of protein I was specifically inhibited by antipain or leupeptin in strain K12, whereas several other proteins were also affected in strain B. Protein synthesis in strain B was generally more sensitive to inhibition by antipain than that in strain K12. 相似文献
53.
K Ito 《Nihon seirigaku zasshi. Journal of the Physiological Society of Japan》1976,38(5):221-237
Neural controlling mechanisms between the digastric (jaw-opening) and masseter (jaw-closing) muscles were studied in the cat. High threshold afferent impulses from the anterior belly of the digastric muscle to masseteric montoneurons in the trigeminal motor nucleus induced an EPSP-IPSP sequence of potentials with long latency, and high threshold afferent impulses from the masseter muscle also exerted a similar effect on digastric motoneurons in the same nucleus innervating the anterior belly of the digastric muscle. These results suggest that reciprocal inhibition via Ia interneurons as observed between the flexor and extensor muscles in the spinal cord does not exist between the digastric and masseter muscles in the cat. However, the respective motoneurons innervating the masseter and digastric muscles receive inputs of early excitation-late inhibition via high threshold afferent nerve fibers from each antagonistic muscle. As such, since EPSPs preceding IPSPs are recognized, these high threshold afferent impulses may exert not only a reciprocal inhibitory effect, but also a synchronous excitatory or inhibitory effect on the antagonistic motoneurons. 相似文献
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Ami Takeuchi Yuna Akatsu Takahiro Asahi Yukino Okubo Mariko Ohnuma Hiroshi Teramura Koji Tamura Hiroaki Shimada 《Plant Biotechnology》2022,39(2):195
Potato, Solanum tuberosum L. is an important crop. However, it is difficult to breed potato cultivars by applying conventional crossing methods because potato has a tetraploid genome and is vegetatively propagated. Flower formation and tuber development occur simultaneously. Many potato cultivars hardly produce any fruits after crossing and fail to produce seeds. We report an improved procedure for obtaining progeny seeds by grafting potatoes onto tomatoes. The rate of fruit formation was more than 19% when the grafted potatoes were used for the crossing experiments, whereas crossing using the ungrafted plants showed a rate of 1.1%. This result suggests that our procedure results in the easy acquisition of null-segregant progenies by crossing mutant lines. It is also expected to improve conventional potato breeding. 相似文献
56.
Kazuhiko Hashimoto Shunji Nishimura Tomohiko Ito Naohiro Oka Ryosuke Kakinoki Masao Akagi 《European journal of histochemistry : EJH》2022,66(3)
The cancer/testis antigens (CTAs), New York esophageal squamous cell carcinoma-1 (NY-ESO-1) and melanoma antigen gene (MAGE)-A4 are normally restricted to male germ cells but are aberrantly expressed in several cancers. Considering the limited information regarding their significance in osteosarcoma (OS), the purpose of this study was to determine the clinical significance of NY-ESO-1 and MAGE-A4 expression in OS. Nine patients with OS treated at Kindai University Hospital were included in the study. The median age was 27 years, and median follow-up period was 40 months. The specimens obtained at the time of biopsy were used to perform immunostaining for NY-ESO, MAGE-A4, p53, and Ki-67. The positive cell rates and positive case rates of NY-ESO, MAGE-A4, p53, and Ki-67 were calculated. The correlation between the positive cell rate of immunohistochemical markers was also calculated. The correlation between the positive cell rate of NY-ESO-1 or MAGE-A4 and tumor size or maximum standardized uptake (SUV-max) was also determined. The positive cell rates of NY-ESO-1 or MAGE-A4 in continuous disease-free (CDF) cases were also compared with those in alive with disease (AWD) or dead of disease (DOD) cases. The average positive cell rates of NY-ESO, MAGEA4, p53, and Ki-67 were 71.7%, 85.1%, 16.2%, and 14.7%, and their positive case rates were 33.3%, 100%, 44.4%, and 100%, respectively. The positivity rates of NY-ESO-1 and p53 were strongly correlated, whereas those of NY-ESO-1 and Ki-67 were moderately correlated. The MAGE-A4 and p53 positivity rates and the MAGE-A4 and Ki-67 positive cell rates were both strongly correlated. The NY-ESO-1 and MAGE-A4 positivity rates were moderately correlated. The positive correlation between the NY-ESO-1 positive cell rate and tumor size was medium, and that between the MAGE-A4 positivity rate and SUV-max was very strong. There was no significant difference in the positive cell rates of NY-ESO-1 or MAGE-A4 between CDF cases and AWD or DOD cases. Overall, our results suggest that NY-ESO-1 and MAGE-A4 may be involved in the aggressiveness of OS.Key words: New York esophageal squamous cell carcinoma-1 (NY-ESO-1), melanoma antigen gene (MAGE)- A4, osteosarcoma, prognosis, cancer/testis antigen (CTA), immunohistochemistry 相似文献
57.
The Role of Influenza A Virus Hemagglutinin Residues 226 and 228 in Receptor Specificity and Host Range Restriction 总被引:18,自引:8,他引:18 下载免费PDF全文
Angela Vines Krisna Wells Mikhail Matrosovich Maria R. Castrucci Toshihiro Ito Yoshihiro Kawaoka 《Journal of virology》1998,72(9):7626-7631
Influenza A viruses can be isolated from a variety of animals, but their range of hosts is restricted. For example, human influenza viruses do not replicate in duck intestine, the major replication site of avian viruses in ducks. Although amino acids at positions 226 and 228 of hemagglutinin (HA) of the H3 subtype are known to be important for this host range restriction, the contributions of specific amino acids at these positions to restriction were not known. Here, we address this issue by generating HAs with site-specific mutations of a human virus that contain different amino acid residues at these positions. We also let ducks select replication-competent viruses from a replication-incompetent virus containing a human virus HA by inoculating animals with 1010.5 50% egg infectious dose of the latter virus and identified a mutation in the HA. Our results showed that the Ser-to-Gly mutation at position 228, in addition to the Leu-to-Gln mutation at position 226 of the HA of the H3 subtype, is critical for human virus HA to support virus replication in duck intestine. 相似文献
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Suzuki T Hara I Nakano M Zhao G Lennarz WJ Schindelin H Taniguchi N Totani K Matsuo I Ito Y 《The Journal of biological chemistry》2006,281(31):22152-22160
Peptide:N-glycanase (PNGase) is the deglycosylating enzyme, which releases N-linked glycan chains from N-linked glycopeptides and glycoproteins. Recent studies have revealed that the cytoplasmic PNGase is involved in the degradation of misfolded/unassembled glycoproteins. This enzyme has a Cys, His, and Asp catalytic triad, which is required for its enzymatic activity and can be inhibited by "free" N-linked glycans. These observations prompted us to investigate the possible use of haloacetamidyl derivatives of N-glycans as potent inhibitors and labeling reagents of this enzyme. Using a cytoplasmic PNGase from budding yeast (Png1), Man9GlcNAc2-iodoacetoamide was shown to be a strong inhibitor of this enzyme. The inhibition was found to be through covalent binding of the carbohydrate to a single Cys residue on Png1, and the binding was highly selective. The mutant enzyme in which Cys191 of the catalytic triad was changed to Ala did not bind to the carbohydrate probe, suggesting that the catalytic Cys is the binding site for this compound. Precise determination of the carbohydrate attachment site by mass spectrometry clearly identified Cys191 as the site of covalent attachment. Molecular modeling of N,N'-diacetylchitobiose (chitobiose) binding to the protein suggests that the carbohydrate binding site is distinct from but adjacent to that of Z-VAD-fmk, a peptide-based inhibitor of this enzyme. These results suggest that cytoplasmic PNGase has a separate binding site for chitobiose and other carbohydrates, and haloacetamide derivatives can irreversibly inhibit that catalytic Cys in a highly specific manner. 相似文献
60.