全文获取类型
收费全文 | 1093篇 |
免费 | 75篇 |
出版年
2022年 | 8篇 |
2021年 | 12篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 17篇 |
2015年 | 23篇 |
2014年 | 34篇 |
2013年 | 86篇 |
2012年 | 49篇 |
2011年 | 56篇 |
2010年 | 28篇 |
2009年 | 33篇 |
2008年 | 61篇 |
2007年 | 67篇 |
2006年 | 73篇 |
2005年 | 77篇 |
2004年 | 49篇 |
2003年 | 48篇 |
2002年 | 63篇 |
2001年 | 26篇 |
2000年 | 17篇 |
1999年 | 18篇 |
1998年 | 22篇 |
1997年 | 21篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 20篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 14篇 |
1987年 | 17篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 19篇 |
1983年 | 10篇 |
1982年 | 16篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1966年 | 4篇 |
1965年 | 5篇 |
排序方式: 共有1168条查询结果,搜索用时 31 毫秒
41.
Linolenic acid-[1-14C] was converted to 12-oxo-trans-10-dodecenoic acid, via 12-oxo-cis-9-dodecenoic acid by incubation with chloroplasts of Thea sinensis leaves. Thus, it was confirmed that linolenic acid is split into a C12-oxo-acid, 12-oxo-trans-10-dodecenoic acid, and a C6-aldehyde, trans-2-hexenal, leaf aldehyde, by an enzyme system in chloroplasts of tea leaves. 相似文献
42.
Source of prolactin in human follicular fluid. 总被引:2,自引:0,他引:2
M Ohwaki N Suganuma H Seo A Nawa F Kikkawa O Narita N Matsui Y Tomoda 《Endocrinologia japonica》1992,39(6):601-607
To analyze whether prolactin (PRL) in human follicular fluid (FF) is synthesized locally or derived from the circulation, PRL concentrations of plasma and FF were determined in the patients after ovarian stimulations. The amounts of PRL messenger ribonucleic acid (mRNA) in the follicular tissues during different menstrual phases were also determined. The FF PRL concentration was correlated positively with plasma PRL and highest estradiol levels during the stimulatory cycle. No PRL mRNA sequence was detected in the RNAs extracted from follicles at any stage in the menstrual cycle, although beta-actin mRNA was detected in all samples. In a comparison with pituitary RNA, the PRL mRNA concentration in ovarian follicular tissues seemed to be 10,000 times less than that in the pituitary. These results suggest that FF PRL may not be synthesized locally, but derived from the pituitary via the circulation through passive diffusion, and thus regulated by estrogen. 相似文献
43.
Tomohiro Kiyosue Jiro Nakayama Shinobu Satoh Akira Isogai Akinori Suzuki Hiroshi Kamada Hiroshi Harada 《Planta》1992,186(3):337-342
ECP31, an embryogenic-cell protein from carrot (Daucus carota L.), was purified by sequential column-chromatographic steps and digested by V8 protease on a nitrocellulose membrane. The resultant peptides were separated by reverse-phased column chromatography and sequenced. The sequences obtained were 70–80% homologous to those of a late-embryogenesis-abundant protein (D34) from cotton (Baker et al, 1988, Plant Mol. Biol. 11, 227–291). The level of ECP31 in somatic embryos of carrot was increased by treatment of the embryos with 3.7 · 10–6 M abscisic acid (ABA) for 48 h, and there was no change in this enhanced level for up to 192 h in the presence of ABA. No similar enhancing effect of ABA was observed on the level of ECP31 in embryogenic callus or segments of carrot hypocotyls. In an immunohistochemical analysis, ECP31 was found in epidermal tissue and in the vascular system of ABA-treated somatic embryos.Abbreviations ABA
abscisic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- LEA protein
late-embryogenesis-abundant protein
To whom correspondence should be addressedThis work was supported in part by a grant-in-aid for Special Research in Priority Areas (Project No. 02242102) from the Ministry of Education, Science and Culture, Japan, and by Special Coordination Funds of the Science and Technology Agency of the Japanese Government. 相似文献
44.
Adenine depurination and inactivation of plant ribosomes by an antiviral protein of Mirabilis jalapa (MAP) 总被引:4,自引:0,他引:4
Jiro Kataoka Noriyuki Habuka Masashi Miyano Chikara Masuta Akira Koiwai 《Plant molecular biology》1992,20(6):1111-1119
Mirabilis antiviral protein (MAP) is a single-chain ribosome-inactivating protein (RIP) isolated from Mirabilis jalapa L. It depurinates the 28S-like rRNAs of prokaryotes and eukaryotes. A specific modification in the 25S rRNA of M. jalapa was found to occur during isolation of ribosomes by polyacrylamide/agarose composite gel electrophoresis. Primer extension analysis revealed the modification site to be at the adenine residue corresponding to A4324 in rat 28S rRNA. The amount of endogenous MAP seemed to be sufficient to inactivate most of the homologous ribosomes. The adenine of wheat ribosomes was also found to be removed to some extent by an endogenous RIP (tritin). However, the amount of endogenous tritin seemed to be insufficient for quantitative depurination of the homologous ribosomes.Endogenous MAP could shut down the protein synthesis of its own cells when it spreads into the cytoplasm through breaks of the cells. Therefore, we speculate that MAP is a defensive agent to induce viral resistance through the suicide of its own cells. 相似文献
45.
Downhill movement of litter and its implication for ecological studies in three types of forest in Japan 总被引:2,自引:0,他引:2
Jiro Tsukamoto 《Ecological Research》1991,6(3):333-345
The amount of litter moving down the slope was measured in three types of forest, together with an examination of rain as
a factor in bringing this about. The three forest types were a natural mixed stand ofPinus densiflora and hardwood trees (plot A), aCryptomeria japonica plantation (plot S) and aChamaecyparis obtusa plantation (plot H). The amount of moved litter was quite large in plots A and H, but relatively small in plot S. The rain
factor had little influence on litter movement in plot A, but was the main cause of movement in plot S and (especially) plot
H. It is suggested that measurement of litter input and output not only by traps above ground level, but also by ones on the
ground is essential for determining the cycling of elements inC. obtusa forests. It is also suggested that the decomposition of leaf litter should be studied both on the soil surface and in the
soil inC. obtusa forests. 相似文献
46.
Michiru Tanaka Jiro Hasegawa Junzo Tsutsumi Takeshi Fujita 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1982,231(2):301-310
A highly specific and sensitive method for the determination of the anti-ulcer drug geranylgeranylacetone (GGA) in human serum is described. The extract from serum with hexane was saponified with potassium hydroxide and subjected to silica gel column chromatography to remove interfering substances. GGA in the partially purified extract was then reacted with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine and measured by selected ion monitoring using gas chromatography—mass spectrometry. A low detection limit (1 ng/ml) and high precision were obtained. 相似文献
47.
A study was made to find whether the nodding of the flower stalkin a poppy, Papaver Rhoeas L., immediately after its formationwas triggered by the weight of its flower bud or by positivegeoreaction and the following results were obtained.
- The direction of the nodding was mostly toward the inclinedside of the stalk, which was opposite the leaf, for apical flowerbuds.
- If the weight of the flower bud at stage 1 was cancelledbyapplying a load equivalent to the bud weight, the noddingofthe stalk was not initiated.
- The stalk at stages 1 and2 and the upper part of the stalk(bending zone), as comparedwith the basal part, at later stageswere highly deformableaccording to measurements by the bendingmethod.
- The cellwall of highly deformable stalks was rich in hemicellulosesand that of the basal part was abundant in pectic substances.
48.
Cells of Schizosaccharomyces pombe grown in the presence of aculeacin A, a peptide antibiotic, were lysed resulting the death of cells. Under high osmolarity, the cellular lysis induced by aculeacin A was considerably reduced. The use of synchronous-culture systems distinguished cell elongation from cell division revealed that the sites of aculeacin A-induced lysis on the fission yeast were the end(s) and the cell plate region, corresponded to the regions of the cell wall synthesis. Aculeacin A-resistant survivors exhibited morphological alterations which were swollen at one or both ends of the cell and appeared drumstick or dumbbel like; the wall of the bulge region was observed to be stained with a fluorescent brightener, as well as that of the cell plate region. These effects of aculeacin A are discussed as compared with effects of 2-deoxy-D-glucose. 相似文献
49.
Unsaturated diacylglycerol as a possible messenger for the activation of calcium-activated, phospholipid-dependent protein kinase system 总被引:57,自引:0,他引:57
Y Takai A Kishimoto U Kikkawa T Mori Y Nishizuka 《Biochemical and biophysical research communications》1979,91(4):1218-1224
A small quantity of unsaturated diacylglycerol (DG) sharply decreased the Ca2+ and phospholipid concentrations needed for full activation of a Ca2+-activated, phospholipid-dependent multifunctional protein kinase described earlier (Takai, Y., Kishimoto, A., Iwasa, Y., Kawahara, Y., Mori, T. and Nishizuka, Y. (1979). 3692–3695). In the presence of unsaturated DG and micromolar order of Ca2+, phosphatidylserine (PS) was most relevant with the capacity to activate the enzyme, whereas phosphatidylethanolamine and phosphatidylinositol (PI) were far less effective. Phosphatidylcholine was practically inactive. It is possible, therefore, that unsaturated DG, which may be derived from PI turnover provoked by various extracellular stimulators, acts as a messenger for activating the enzyme, and that Ca2+ and various phospholipids such as PI and PS seem to play a role cooperatively in this unique receptor mechanism. 相似文献
50.
Summary A 5-year-old boy with multiple minor anomalies and mental retardation was found to have chromosomal condition of 46,XY,inv dup(9p)(pterp13::p21p24::p13qter). The clinical features of the propositus fit well with those of trisomy 9p which have been established to be a clinical entity. 相似文献