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991.
992.
993.
Takahiro Ishikawa Kasumi Maeda Koichi Hayakawa Takakazu Kojima 《Journal of Molecular Catalysis .B, Enzymatic》1996,1(3-6):173-179
Microbial production of a 6-hydroxy-3-pyridylmethyl compound from 3-pyridylmethyl compound was investigated. The hydroxylation of 3-(methylaminomethyl)pyridine to 5-(methylaminomethyl)-2(1H)-pyridinone, tautomer of 2-hydroxy-5(methylaminomethyl)pyridine, by resting cells ofArthrobacter ureafaciens JCM3873 was found to proceed regio- and chemo-selectively with an almost quantitative yield. The addition of molybdate ion and nicotine as an inducer to the culture medium was required for the preparation of cells containing high hydroxylation activity. The optimal temperature and pH for the hydroxylation by using resting cells were 35°C and around 7, respectively. This hydroxylation enzyme does undergo inhibition by the substrate. The inhibitory effect could be eliminated by stepwise feeding of the substrate. Under adequate conditions, 23 mg/ml of 5-(methylaminomethyl)-2(1H)-pyridinone was produced with a molar yield of nearly 100% from 3-(methylaminomethyl)pyridine. 相似文献
994.
Developmental gene expression of gastrin receptor in rat stomach 总被引:10,自引:0,他引:10
He-Yao Wang Yoshikazu Kinoshita M. S Hassan Yumi Matsushima Hirokazu Fukui Toru Maekawa Akihiko Okada Shinya Waki Chiharu Kawanami Kiyohiko Kishi Makoto Watanabe Sakan Maeda Tsutomu Chiba 《Regulatory peptides》1997,70(2-3):183-189
Gastrin, which is present in fetal plasma, may have important roles in the development of gastric mucosa, since it is not only a potent stimulator of gastric acid secretion but also a growth promoting factor. Gastrin regulates various cellular functions via its receptors on cell membrane. Therefore, in order to elucidate a role for gastrin in the development of gastrointestinal system during gestation, Northern blot analysis was performed. The results of the study suggested that gastrin receptor is mainly present on parietal cells. Furthermore, proton pump and gastrin receptor gene expressions in parietal cells were strongly stimulated by the administration of exogenous gastrin. In conclusion, gastrin may be involved in the developmental change of parietal cells through its receptors. 相似文献
995.
Hisao Oka Yoshitomo Ikai Yuko Ito Junko Hayakawa Ken-ichi Harada Makoto Suzuki Hiroko Odani Kenji Maeda 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,693(2):687
To reliably identify the residual tetracycline antibiotics (TCs), oxytetracycline (OTC), tetracycline, chlortetracycline (CTC) and doxycycline (DC), in bovine tissues, we have established a confirmation method using electrospray ionization liquid chromatography–tandem mass spectrometry (ESI LC–MS–MS) with daughter ion scan. All TCs gave [M+H−NH3]+ and [M+H−NH3−H2O]+ as the product ions, except for DC when [M+H]+ was selected as the precursor ion. The combination of C18 cartridge clean-up and the present ESI LC–MS–MS method can reliably identify TCs fortified at a concentration of 0.1 ppm in bovine tissues, including liver, kidney and muscle, and has been successfully applied to the identification of residual OTC in bovine liver and residual CTC in bovine muscle samples previously found at concentrations of 0.58 ppm and 0.38 ppm by LC, respectively. 相似文献
996.
M Takahashi N Inoue K Ohishi Y Maeda N Nakamura Y Endo T Fujita J Takeda T Kinoshita 《The EMBO journal》1996,15(16):4254-4261
Many eukaryotic cell surface proteins are bound to the membrane via the glycosylphosphatidylinositol (GPI) anchor that is covalently linked to their carboxy-terminus. The GPI anchor precursor is synthesized in the endoplasmic reticulum (ER) and post-translationally linked to protein. We cloned a human gene termed PIG-B (phosphatidylinositol glycan of complementation class B) that is involved in transferring the third mannose. PIG-B encodes a 554 amino acid, ER transmembrane protein with an amino-terminal portion of approximately 60 amino acids on the cytoplasmic side and a large carboxy-terminal portion of 470 amino acids within the ER lumen. A mutant PIG-B lacking the cytoplasmic portion remains active, indicating that the functional site of PIG-B resides on the lumenal side of the ER membrane. The PIG-B gene was localized to chromosome 15 at q21-q22. This autosomal location would explain why PIG-B is not involved in the defective GPI anchor synthesis in paroxysmal nocturnal hemoglobinuria, which is always caused by a somatic mutation of the X-linked PIG-A gene. 相似文献
997.
998.
Takayoshi Tokiwa Junko Kano Xian-Yian Meng Raman Bahulekar Makoto Kodama 《Biotechnology Techniques》1996,10(11):845-848
Summary Adult rat hepatocytes in primary culture formed floating, non-spheroidal aggregates on the surfaces coated with 1 % polyacrylamide. In the cells of aggregates, DNA synthetic capacity was limited, but albumin secreting capacity was maintained at least for 2 weeks. These properties were influenced by addition of serum. 相似文献
999.
Hirohisa Tsuda Catherine E. Maynard-Currie Laura H. Reid Takayuki Yoshida Koji Edamura Nobuyo Maeda Oliver Smithies Aya Jakobovits 《Genomics》1997,42(3):413
To obtain useful hypoxanthine phosphoribosyltransferase (HPRT)-deficient mouse ES cell lines, two different methods were employed: (i) selection of spontaneous 6-TG-resistant mutants and (ii) gene targeting of theHPRTlocus. The first approach resulted in the establishment of E14.1TG3B1, a spontaneous HPRT-deficient cell line with an insertional mutation of 203 bp in the third exon of theHPRTgene. The insert is highly homologous to the B2 mouse repetitive element and has all the expected retroposon characteristics, thus providing an example of gene inactivation by retroposon insertion. This clone exhibited stable 6-TG resistance and high germ-line transmission frequency. Thus E14.1TG3B1 is a useful ES cell line for modifying the mouse genome using theHPRTgene as a selection marker and for transmission at a high frequency into the mouse germ line. The second approach resulted in a 55-kb deletion of the mouseHPRTlocus, demonstrating the feasibility of replacement-targeting vectors to generate large genomic DNA deletions. 相似文献
1000.
Junko Adachi Kuniaki Watanabe Kiichi Fukui Nobuko Ohmido Keiko Kosuge 《Journal of plant research》1997,110(3):371-377
The chromosomal locations of the 45S (18S-5.8S-26S) and 5S ribosomal DNA in theBrachyscome lineariloba complex and two related species have been determined by the use of multicolor fluorescencein situ hybridization (McFISH). TheBrachyscome lineariloba complex includes five cytodemes with 2n=4, 8, 10, 12 and 16. Each of the 5S and 45S rDNA loci occurs at two sites on chromosomes in cytodemes with 2n=4. While in cytodemes with 2n=8, 10, 12 and 16, the number of 5S rDNA sites increases from four to eight paralleled to the genomic addition of diploid
(4 chromosomes) or haploid (2 chromosomes) dosage. Of the 5S rDNA sites, only one pair is major, except for the cytodeme with
2n=10. The remaining 5S rDNA sites are minor and seem to have reduced the unit number of the 5S rDNA during the successive genomic
additions. The 45S rDNA site is detected only at two nucleolar organizing regions in all cytodemes regardless of successive
genomic addition. The loss or diminution of 45S rDNA sequences seem to have proceeded more rapidly than 5S rDNA sequences
in theB. lineariloba complex. 相似文献