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991.
992.
Timité G Mitaine-Offer AC Miyamoto T Tanaka C Mirjolet JF Duchamp O Lacaille-Dubois MA 《Phytochemistry》2011,72(6):503-507
Three oleanane-type saponins, 3-O-β-d-glucopyranosylechinocystic acid 28-O-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (1), 3-O-β-d-glucopyranosylechinocystic acid 28-O-α-l-arabinopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (2), 3-O-β-d-glucopyranosylcaulophyllogenin 28-O-β-d-apiofuranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[β-d-apiofuranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-α-l-rhamnopyranosyl ester (3) were isolated from the whole plant of Arenaria montana. Their unusual structures for the Caryophyllaceae family were established mainly by 2D NMR techniques and mass spectrometry. 相似文献
993.
The structural gene for sphingomyelinase (SMase) from Streptomyces
griseocarneus, was introduced into Streptomyces lividans using a shuttle vector, pUC702, for Escherichia coli/S. lividans. High-level secretory production of SMase was achieved using the promoter, signal sequence and terminator regions of phospholipase
D from Streptoverticillium cinnamoneum. The transformant constitutively expressed a high specific activity of SMase extracellularly during batch culture. Maximum
SMase activity (555 ± 114 U/mg protein) was with 1.75 M MgCl2 which was about 50-fold more than that with 10 mM MgCl2. 相似文献
994.
Ribonucleopeptide (RNP) is a new class of scaffold for modular fluorescent sensors. We report here a short RNA motif that induces an efficient communication between the structural changes associated with the ligand-binding event of RNA aptamer and an optical response of a fluorescent RNP module. An optimized short RNA motif was used as a communication module for the rational design of modular RNP sensors. A modular combination of a GTP-binding RNA aptamer, the short RNA motif and the fluorophore-labeled RNP module afforded a fluorescent GTP sensor that retain the ligand-binding affinity of the parent aptamer. 相似文献
995.
Saito T Obitsu T Minamoto C Sugiura T Matsumura N Ueno S Kishi A Katsumata S Nakai H Toda M 《Bioorganic & medicinal chemistry》2011,19(20):5955-5966
To identify structurally novel CRF1 receptor antagonists, a series of bicyclic core antagonists, pyrazolo[1,5-a]pyrimidines, triazolo[1,5-a]pyrimidines, imidazo[1,2-a]pyrimidines and pyrazolo[1,5-a][1,3,5]triazines were designed, synthesized and evaluated as CRF1 receptor antagonists. Compounds 2-27 showed binding affinity (IC(50)=4.2-418 nM) and antagonist activity (EC(50)=4.0-889 nM). Compound 5 was found to show oral efficacy in an Elevated Plus Maze test in rats. Further chemical modification of them led us to discovery of the tricyclic core antagonists pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidines. The discovery process of these compounds is presented, as is the study of the structure-activity relationship. 相似文献
996.
Nishizawa R Nishiyama T Hisaichi K Minamoto C Matsunaga N Takaoka Y Nakai H Jenkinson S Kazmierski WM Tada H Sagawa K Shibayama S Fukushima D Maeda K Mitsuya H 《Bioorganic & medicinal chemistry letters》2011,21(4):1141-1145
Following the discovery that hydroxylated derivative 3 (Fig. 1) was one of the oxidative metabolites of the original lead 1, it was found that hydroxylated compound 4 possesses higher in vitro anti-HIV potency than the corresponding non-hydroxylated compound 2. Structural hybridation of 4 with the orally available analog 5 resulted in another orally-available spirodiketopiperazine CCR5 antagonist 6a that possesses more favorable pharmaceutical profile for use as a drug candidate. 相似文献
997.
Naoko Nakano Kota Maeyama Nobuo Sakata Fumiko Itoh Ryosuke Akatsu Miki Nakata Yuki Katsu Souichi Ikeno Yoko Togawa Thanh Thao Vo Nguyen Yukihide Watanabe Mitsuyasu Kato Susumu Itoh 《The Journal of biological chemistry》2014,289(18):12680-12692
Transforming growth factor (TGF)-β signaling is deliberately regulated at multiple steps in its pathway from the extracellular microenvironment to the nucleus. However, how TGF-β signaling is activated or attenuated is not fully understood. We recently identified transmembrane prostate androgen-induced RNA (TMEPAI), which is involved in a negative feedback loop of TGF-β signaling. When we searched for a family molecule(s) for TMEPAI, we found C18ORF1, which, like TMEPAI, possesses two PY motifs and one Smad-interacting motif (SIM) domain. As expected, C18ORF1 could block TGF-β signaling but not bone morphogenetic protein signaling. C18ORF1 bound to Smad2/3 via its SIM and competed with the Smad anchor for receptor activation for Smad2/3 binding to attenuate recruitment of Smad2/3 to the TGF-β type I receptor (also termed activin receptor-like kinase 5 (ALK5)), in a similar fashion to TMEPAI. Knockdown of C18ORF1 prolonged duration of TGF-β-induced Smad2 phosphorylation and concomitantly potentiated the expression of JunB, p21, and TMEPAI mRNAs induced by TGF-β. Consistently, TGF-β-induced cell migration was enhanced by the knockdown of C18ORF1. These results indicate that the inhibitory function of C18ORF1 on TGF-β signaling is similar to that of TMEPAI. However, in contrast to TMEPAI, C18ORF1 was not induced upon TGF-β signaling. Thus, we defined C18ORF1 as a surveillant of steady state TGF-β signaling, whereas TMEPAI might help C18ORF1 to inhibit TGF-β signaling in a coordinated manner when cells are stimulated with high levels of TGF-β. 相似文献
998.
Nobuaki Ozeki Naoko Hase Taiki Hiyama Hideyuki Yamaguchi Rie Kawai Ayami Kondo Kazuhiko Nakata Makio Mogi 《Experimental cell research》2014
We previously established a method for differentiating induced pluripotent stem cells and embryonic stem (ES) cells into α2 integrin-positive odontoblast-like cells. We also reported that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation and suppresses apoptosis in these cells, suggesting that MMP-3 plays a potentially unique physiological role in the regeneration of odontoblast-like cells. Here, we examined whether up-regulation of MMP-3 activity by IL-1β was mediated by Wnt signaling and led to increased proliferation of odontoblast-like cells. IL-1β increased mRNA and protein levels of Wnt5a, Wnt5b and the Wnt receptor Lrp5. Exogenous Wnt5a and Wnt5b were found to increase MMP-3 mRNA, protein and activity, and interestingly the rate of proliferation in these cells. Treatment with siRNAs against Wnt5a, Wnt5b and Lrp5 suppressed the IL-1β-induced increase in MMP-3 expression and suppressed cell proliferation, an effect rescued by application of exogenous Wnt5. These results demonstrate the sequential involvement of Wnt5, Lrp5 and MMP-3 in effecting IL-1β-induced proliferation of ES cell-derived odontoblast-like cells. 相似文献
999.
Difference in cesium accumulation among rice cultivars grown in the paddy field in Fukushima Prefecture in 2011 and 2012 总被引:1,自引:0,他引:1
Yoshihiro Ohmori Yayoi Inui Masataka Kajikawa Atsumi Nakata Naoyuki Sotta Koji Kasai Shimpei Uraguchi Nobuhiro Tanaka Sho Nishida Takahiro Hasegawa Takuya Sakamoto Yuko Kawara Kayoko Aizawa Haruka Fujita Ke Li Naoya Sawaki Koshiro Oda Ryuichiro Futagoishi Takahiro Tsusaka Satomi Takahashi Junpei Takano Shinji Wakuta Akira Yoshinari Masataka Uehara Shigeki Takada Hayato Nagano Kyoko Miwa Izumi Aibara Takuya Ojima Kaoru Ebana Satoru Ishikawa Kuni Sueyoshi Hiroshi Hasegawa Tetsuro Mimura Mari Mimura Natsuko I. Kobayashi Jun Furukawa Daisuke Kobayashi Toshiyasu Okouchi Keitaro Tanoi Toru Fujiwara 《Journal of plant research》2014,127(1):57-66
After the accident of the Fukushima 1 Nuclear Power Plant in March 2011, radioactive cesium was released and paddy fields in a wide area including Fukushima Prefecture were contaminated. To estimate the levels of radioactive Cs accumulation in rice produced in Fukushima, it is crucial to obtain the actual data of Cs accumulation levels in rice plants grown in the actual paddy field in Fukushima City. We herein conducted a two-year survey in 2011 and 2012 of radioactive and non-radioactive Cs accumulation in rice using a number of rice cultivars grown in the paddy field in Fukushima City. Our study demonstrated a substantial variation in Cs accumulation levels among the cultivars of rice. 相似文献
1000.
Emmanuel Oluwadare Balogun Daniel Ken Inaoka Tomoo Shiba Yasutoshi Kido Chiaki Tsuge Takeshi Nara Takashi Aoki Teruki Honma Akiko Tanaka Masayuki Inoue Shigeru Matsuoka Paul A. M. Michels Kiyoshi Kita Shigeharu Harada 《Molecular microbiology》2014,94(6):1315-1329
The glycerol kinase (GK) of African human trypanosomes is compartmentalized in their glycosomes. Unlike the host GK, which under physiological conditions catalyzes only the forward reaction (ATP‐dependent glycerol phosphorylation), trypanosome GK can additionally catalyze the reverse reaction. In fact, owing to this unique reverse catalysis, GK is potentially essential for the parasites survival in the human host, hence a promising drug target. The mechanism of its reverse catalysis was unknown; therefore, it was not clear if this ability was purely due to its localization in the organelles or whether structure‐based catalytic differences also contribute. To investigate this lack of information, the X‐ray crystal structure of this protein was determined up to 1.90 Å resolution, in its unligated form and in complex with three natural ligands. These data, in conjunction with results from structure‐guided mutagenesis suggests that the trypanosome GK is possibly a transiently autophosphorylating threonine kinase, with the catalytic site formed by non‐conserved residues. Our results provide a series of structural peculiarities of this enzyme, and gives unexpected insight into the reverse catalysis mechanism. Together, they provide an encouraging molecular framework for the development of trypanosome GK‐specific inhibitors, which may lead to the design of new and safer trypanocidal drug(s). 相似文献