全文获取类型
收费全文 | 984篇 |
免费 | 73篇 |
专业分类
1057篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 14篇 |
2015年 | 22篇 |
2014年 | 32篇 |
2013年 | 72篇 |
2012年 | 45篇 |
2011年 | 45篇 |
2010年 | 21篇 |
2009年 | 32篇 |
2008年 | 35篇 |
2007年 | 45篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 46篇 |
2003年 | 39篇 |
2002年 | 51篇 |
2001年 | 24篇 |
2000年 | 35篇 |
1999年 | 32篇 |
1998年 | 19篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 23篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 19篇 |
1988年 | 26篇 |
1987年 | 27篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 14篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 9篇 |
1968年 | 3篇 |
排序方式: 共有1057条查询结果,搜索用时 15 毫秒
11.
Go Suzuki Wataru Okada Yoko Yasutake Hidekazu Yamamoto Iwao Tanita Hiroshi Yamashita Takeshi Hayashibara Toshiaki Komatsu Toru Kanyama Masahito Inoue Masashi Yamazaki 《Restoration Ecology》2020,28(5):1172-1182
Larval recruitment is essential for sustaining coral communities and a fundamental tool in some interventions for reef restoration. To improve larval supply and post‐settlement survival in sexually assisted coral restoration efforts, an integrated in situ collector system, the larval cradle, was designed to collect spawned gametes then culture the resulting larvae until settled on artificial substrates. The final design of the larval cradle was cylindrical, a nylon mesh structure with a volume of 9 m3, suspended in the sea and extending vertically toward the seabed. We found three key design features that improved the efficiency of the apparatus: (1) an open area of sea surface and mesh size of less than 100 μm produced high fertilization and optimal survival (>90%), (2) a special skirt‐shaped net (3 m in diameter) with a connection hose for attaching the cradle to collect bundles from many adult colonies over a wide area and at various depths, and (3) adding short square tube pieces, called square hollow sections, as a substrate for enhancing larval settlement and survival, to a larval cradle at 4 days after spawning was optimal for uniform settlement. This system allowed not only the collection of several million eggs, but also subsequent production of several thousand settled juvenile corals, without land facilities. Our design achieved several hundred times higher survival for early life stages of Acropora tenuis compared to nature. 相似文献
12.
Studies on DNA markers (D4S10 and D4S43/S127) genetically linked to Huntington's disease in Japanese families 总被引:1,自引:0,他引:1
Ichiro Kanazawa Ikuko Kondo Joh-E Ikeda Teruaki Ikeda Yuichior Shizu Mitsuo Yoshida Hirotaro Narabayashi Shigetoshi Kuroda Hisayuki Tsunoda Eiji Mizuta Yoko Okuno Kiyotaka Sugawara Miho Murata Mafuyu Takahashi James F. Gusella 《Human genetics》1990,85(3):257-260
Summary This is the first full report on the genetic linkage between Japanese Huntington's disease and the DNA markers D4S10 and D4S43/S127. With use of the HindIII, BglI, and EcoRI polymorphisms detected at D4S10, and the combination of all these polymorphisms to give composite haplotypes, nine Japanese Huntington's disease families were found to be informative. Three recombinants for D4S10 were detected in these families, giving a maximum lod score of 1.662 at a of 0.10. Similarly, when we used the MspI and PvuII polymorphisms detected by D4S43/S127, five families gave informative results. No recombinant was detected in these families, giving a maximum lod score of 3.348 at a of 0.00. These results clearly support the view that the Japanese Huntington's disease gene may be identical with the Western gene, in spite of the lower prevalence rate in Japan. 相似文献
13.
Takashi Sugawara 《Journal of plant research》1987,100(4):335-348
The floral vascular anatomy of 12 species representing each ofAsarum s. str.,Asiasarum, Geotaenium, Heterotropa andHexastylis are compared to clarify intergeneric relationships. The five genera have basically similar structures in floral morphology
and vasculature, and consistently have a six-carpelled compound ovary and the associated similar placental vasculature. They
show, however, a significant difference in the position and the constituent of the “ventral” carpellary bundles in the placental
axis betweenAsiasarum-Heterotropa-Hexastylis andAsarum-Geotaenium. InAsiasarum, Heterotropa andHexastylis the ventral bundles of each carpel are basically free and antilocular as expected in the least specialized compound ovary
of angiosperms; in contrast, inAsarum andGeotaenium the ventral carpellary bundles are antiseptal and heterogenous (i.e., formed by the lateral fusion of ventral bundles of
adjacent carpels). Shared probable apomorphic floral vasculature, as well as shared single style-column, suggests the closest
mutual relationships betweenAsarum andGeotaenium. In terms of floral morphology and anatomy,Asiasarum, Heterotropa andHexastylis retain plesiomorphies. Possible chromosomal evolution in the related genera is also discussed. 相似文献
14.
15.
Ogawa A Murakami C Kamisuki S Kuriyama I Yoshida H Sugawara F Mizushina Y 《Bioorganic & medicinal chemistry letters》2004,14(13):3539-3543
A new isochroman derivative named pseudodeflectusin was isolated from a culture broth of Aspergillus pseudodeflectus. The structure was determined by spectroscopic means as 9-hydroxy-7-methyl-2-(methylethylidine)-furano[3,2-H]isochroman-3-one. This compound exhibited cytotoxicity for several human cancer cell lines from the stomach (NUGC-3), cervix (HeLa-S3), and peripheral blood (HL-60), but did not affect those from the lung (A549) or colon (DLD-1). The LD50 value of this compound for HL-60 cells was 39 microM. 相似文献
16.
After cytosol proteins in the mouse liver were separated by nondenaturing two-dimensional electrophoresis (2-DE), activities of several enzymes, such as fructose bisphosphatase, sorbitol dehydrogenase and malate dehydrogenase, transferase and sorbitol dehydrogenase, or several dehydrogenases, were analyzed on the same 2-D gel. Further, peptidase (or protease) activity can be examined by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) when peptides such as angiotensin and adenocorticotropic hormone are incubated in the presence of the cytosol protein separated by nondenaturing 2-DE. Sequence structures of proteins on the 2-D gel were analyzed by peptide mass fingerprinting using MALDI-TOF-MS or by peptide sequencing using electrospray ionization-tandem mass spectrometry (ESI-MS/MS). The combination of activity and sequence structure accurately verified the position and activity range of the separated enzymes on the nondenaturing 2-D gel. From these results, we created a nondenaturing 2-D enzyme profile involving activities and sequence structure of cytosol proteins from mouse liver. This profile can be used for checking whether activities of enzymes were specifically or nonspecifically inhibited by inhibitors. 相似文献
17.
Hatakeyama T Matsuo N Shiba K Nishinohara S Yamasaki N Sugawara H Aoyagi H 《Bioscience, biotechnology, and biochemistry》2002,66(1):157-163
CEL-I is one of the Ca2+-dependent lectins that has been isolated from the sea cucumber, Cucumaria echinata. This protein is composed of two identical subunits held by a single disulfide bond. The complete amino acid sequence of CEL-I was determined by sequencing the peptides produced by proteolytic fragmentation of S-pyridylethylated CEL-I. A subunit of CEL-I is composed of 140 amino acid residues. Two intrachain (Cys3-Cys14 and Cys31-Cys135) and one interchain (Cys36) disulfide bonds were also identified from an analysis of the cystine-containing peptides obtained from the intact protein. The similarity between the sequence of CEL-I and that of other C-type lectins was low, while the C-terminal region, including the putative Ca2+ and carbohydrate-binding sites, was relatively well conserved. When the carbohydrate-binding activity was examined by a solid-phase microplate assay, CEL-I showed much higher affinity for N-acetyl-D-galactosamine than for other galactose-related carbohydrates. The association constant of CEL-I for p-nitrophenyl N-acetyl-beta-D-galactosaminide (NP-GalNAc) was determined to be 2.3 x 10(4) M(-1), and the maximum number of bound NP-GalNAc was estimated to be 1.6 by an equilibrium dialysis experiment. 相似文献
18.
19.
Hisayoshi Okazaki Toshihiko Kanzaki Asako Sugawara Hideo Fukuda 《Bioscience, biotechnology, and biochemistry》2013,77(12):1410-1420
A study was made on the differences between Brevibacterium thiogenitalis No. 653 and its oleic acid-requiring mutant D-248 in some physiological characteristics.The most important difference of the characteristics was found in their intracellular fatty acid contents. Namely, the cellular oleic acid content of D-248 was scarcely affected by biotin but limited by the oleic acid which was added to the medium.On the other hand, various enzyme activities and rates of oxygen uptake for several organic acids were found to be slightly different between the two strains.These observations suggest that oleic acid has an important role for the production of l-glutamic acid.The effect of biotin and oleic acid on the cellular fatty acid contents, and the relation between the cellular fatty acid contents and the productivity of l-glutamic acid were investigated using Brevibacterium thiogenitalis No. 653 and its oleic acid-requiring mutant, D-248.While the synthesis of palmitic acid in D-248 was stimulated by biotin and competitively reversed by oleic acid added to the culture medium, the level of cellular oleic acid was scarcely affected by biotin but regulated by oleic acid in the medium.For the productivity of L-glutamic acid, the most important factor was the level of cellular oleic acid, and the effect of cellular palmitic acid was considerably weak. This relation was subjected to a figuration and able to be expressed on the whole as one exponential-like curve. An amount of over 70 per cent of cellular fatty acids was distributed in the phospholipid fraction and its fatty acid composition was almost the same as that of whole cells. 相似文献
20.
Naoki Sugawara Dan Li Chieko Sugawara Hirotsugu Miyake 《Biological trace element research》1995,49(2-3):161-169
Fischer rats were a fed diet supplied with copper chloride (150–600 ppm) for 60 d from weaning. Serum (glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities were increased with the increase of Cu concentration in the diet. Biliary excretion of Cu was related to the dietary Cu level. Depositions of hepatic and renal Cu were also related to the dietary Cu level in a dose-dependent manner. In particular, hepatic (155.2±13.3 μg/g) and renal (44.9±4.4 μg/g) Cu concentrations increased abruptly in the Cu-600 ppm group. In the liver, about 60% of Cu was distributed in the soluble fraction (100,000 g supernatant). In the Cu-600 ppm group, 25% of cystosolic Cu was bound to metallothionein (MT). Our results suggest that chronic exposure to Cu appears to have a deleterious effect on the hepatic function, and further, that even in rats with normal biliary Cu excretion, clearance of Cu from the liver may be marginal when dietary Cu is near the 600-ppm level. Although Cu is an essential nutrient, an overload of Cu should be avoided. 相似文献