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991.
992.
Saito A Doi Y Tanaka A Matsuura N Ubukata M Nakajima N 《Bioorganic & medicinal chemistry》2004,12(18):4783-4790
A systematic synthesis of four natural epicatechin series procyanidin trimers [[4,8:4",8"]-2,3-cis-3,4-trans: 2",3"-cis-3",4"-trans: 2,3-trans-(-)-epi-catechin-(-)-epicatechin-(+)-catechin, [4,8:4",8"]-2,3-cis-3,4-trans: 2",3"-cis-3",4"-trans: 2,3-cis-tri-(-)-epicatechin: procyanidin C1, [4,8:4",8"]-2,3-cis-3,4-trans: 2",3"-trans-3",4"-trans: 2,3-trans-(-)-epicatechin-(+)-catechin-(+)-catechin: procyanidin C4, and [4,8:4",8"]-2,3-cis-3,4-trans: 2",3"-trans-3",4"-trans: 2,3-cis-(-)-epicatechin-(+)-catechin-(-)-epicatechin] is described. Condensation of (2R,3R,4S)-5,7,3'4'-tetra-O-benzyl-4-(2"-ethoxyethyloxy)flavan derived from (-)-epicatechin as an electrophile with the dimeric nucleophiles in the presence of TMSOTf followed by deprotection yielded trimers. Inhibitory activities on the Maillard reaction and antioxidant activity on lipid peroxide of the synthesized oligomers were also investigated. 相似文献
993.
Fumie Iraha Kenji Oki Takatsugu Kobayashi Satoshi Ohno Takashi Yokogawa Kazuya Nishikawa Shigeyuki Yokoyama Kensaku Sakamoto 《Nucleic acids research》2010,38(11):3682-3691
Non-natural amino acids have been genetically encoded in living cells, using aminoacyl-tRNA synthetase–tRNA pairs orthogonal to the host translation system. In the present study, we engineered Escherichia coli cells with a translation system orthogonal to the E. coli tyrosyl-tRNA synthetase (TyrRS)–tRNATyr pair, to use E. coli TyrRS variants for non-natural amino acids in the cells without interfering with tyrosine incorporation. We showed that the E. coli TyrRS–tRNATyr pair can be functionally replaced by the Methanocaldococcus jannaschii and Saccharomyces cerevisiae tyrosine pairs, which do not cross-react with E. coli TyrRS or tRNATyr. The endogenous TyrRS and tRNATyr genes were then removed from the chromosome of the E. coli cells expressing the archaeal TyrRS–tRNATyr pair. In this engineered strain, 3-iodo-l-tyrosine and 3-azido-l-tyrosine were each successfully encoded with the amber codon, using the E. coli amber suppressor tRNATyr and a TyrRS variant, which was previously developed for 3-iodo-l-tyrosine and was also found to recognize 3-azido-l-tyrosine. The structural basis for the 3-azido-l-tyrosine recognition was revealed by X-ray crystallography. The present engineering allows E. coli TyrRS variants for non-natural amino acids to be developed in E. coli, for use in both eukaryotic and bacterial cells for genetic code expansion. 相似文献
994.
Katsue Suzuki-Inoue Osamu Inoue Guo Ding Satoshi Nishimura Kazuya Hokamura Koji Eto Hirokazu Kashiwagi Yoshiaki Tomiyama Yutaka Yatomi Kazuo Umemura Yonchol Shin Masanori Hirashima Yukio Ozaki 《The Journal of biological chemistry》2010,285(32):24494-24507
CLEC-2 has been described recently as playing crucial roles in thrombosis/hemostasis, tumor metastasis, and lymphangiogenesis. The snake venom rhodocytin is known as a strong platelet activator, and we have shown that this effect is mediated by CLEC-2 (Suzuki-Inoue, K., Fuller, G. L., García, A., Eble, J. A., Pöhlmann, S., Inoue, O., Gartner, T. K., Hughan, S. C., Pearce, A. C., Laing, G. D., Theakston, R. D., Schweighoffer, E., Zitzmann, N., Morita, T., Tybulewicz, V. L., Ozaki, Y., and Watson, S. P. (2006) Blood 107, 542–549). Podoplanin, which is expressed on the surface of tumor cells, is an endogenous ligand for CLEC-2 and facilitates tumor metastasis by inducing platelet aggregation. Mice deficient in podoplanin, which is also expressed on the surface of lymphatic endothelial cells, show abnormal patterns of lymphatic vessel formation. In this study, we report on the generation and phenotype of CLEC-2-deficient mice. These mice are lethal at the embryonic/neonatal stages associated with disorganized and blood-filled lymphatic vessels and severe edema. Moreover, by transplantation of fetal liver cells from Clec-2−/− or Clec-2+/+ embryos, we were able to demonstrate that CLEC-2 is involved in thrombus stabilization in vitro and in vivo, possibly through homophilic interactions without apparent increase in bleeding tendency. We propose that CLEC-2 could be an ideal novel target protein for an anti-platelet drug, which inhibits pathological thrombus formation but not physiological hemostasis. 相似文献
995.
Ito A Tauchi H Kobayashi J Morishima K Nakamura A Hirokawa Y Matsuura S Ito K Komatsu K 《Biochemical and biophysical research communications》1999,265(3):716-721
Cells from Nijmegen breakage syndrome (NBS) display multiple phenotypes, such as chromosomal instability, hypersensitivity to cell killing from ionizing radiation, and possibly abnormal cell cycle checkpoints. NBS1, a gene mutated in NBS patients, appears to encode a possible repair protein, which could form the foci of a sensor-like molecular complex capable of detecting DNA double strand breaks, however, it has no kinase domain for signaling DNA damage. Here, we report that the stable expression of NBS1 cDNA in NBS cells after transfection results in the complete restoration of foci formation in the nucleus, and in normal cell survival after irradiation. The prolonged G2 block observed after irradiation was also abolished by expression of NBS1, providing additional confirmation that the G2 checkpoint is abrogated in NBS cells. These results suggest that a defective NBS1 protein could be the sole cause of the NBS phenotype, and that NBS1 likely interacts with another protein(s) to produce the entire range of NBS phenotypic expression. 相似文献
996.
Tanaka H Fujita K Sagisaka A Tomimoto K Imanishi S Yamakawa M 《Molecular biotechnology》2009,41(2):173-179
RNAi knockdown by using shRNA expression plasmids is widely used to determine the function of individual genes in mammals. Here we developed a simple method to create an IR DNA in a U6 small nuclear RNA promoter-based parent vector using a single-stranded IR DNA with short hairpin structure and Bst DNA polymerase. Furthermore, we demonstrated that the shRNA expression plasmids constructed by our method effectively induced target-specific RNAi in the silkworm cell line. We also found that sequence preference in the silkworm cell line was much lower than in mammalian cells and shRNA-induced RNAi was influenced by the length of the stem region. 相似文献
997.
998.
Atsushi Tsukamoto Kazuya Serizawa Reiichiro Sato Jumpei Yamazaki Tomo Inomata 《Experimental Animals》2015,64(1):57-64
Selecting the appropriate anesthetic protocol for the individual animal is an essential
part of laboratory animal experimentation. The present study compared the characteristics
of four anesthetic protocols in mice, focusing on the vital signs. Thirty-two male ddY
mice were divided into four groups and administered anesthesia as follows: pentobarbital
sodium monoanaesthesia; ketamine and xylazine combined (K/X); medetomidine, midazolam, and
butorphanol combined (M/M/B); and isoflurane. In each group, rectal temperature, heart
rate, respiratory rate, and O2 saturation (SPO2) were measured, and
the changes over time and instability in these signs were compared. The anesthetic depth
was also evaluated in each mouse, and the percentage of mice achieving surgical anesthesia
was calculated. K/X anesthesia caused remarkable bradycardia, while the respiratory rate
and SPO2 were higher than with the others, suggesting a relatively strong
cardiac influence and less respiratory depression. The M/M/B group showed a relatively
lower heart rate and SPO2, but these abnormalities were rapidly reversed by
atipamezole administration. The pentobarbital group showed a lower SPO2, and
62.5% of mice did not reach a surgical anesthetic depth. The isoflurane group showed a
marked decrease in respiratory rate compared with the injectable anesthetic groups.
However, it had the most stable SPO2 among the groups, suggesting a higher
tidal volume. The isoflurane group also showed the highest heart rate during anesthesia.
In conclusion, the present study showed the cardiorespiratory characteristics of various
anesthetic protocols, providing basic information for selecting an appropriate anesthetic
for individual animals during experimentation. 相似文献
999.
1000.