全文获取类型
收费全文 | 7830篇 |
免费 | 567篇 |
国内免费 | 9篇 |
出版年
2023年 | 22篇 |
2022年 | 20篇 |
2021年 | 100篇 |
2020年 | 61篇 |
2019年 | 88篇 |
2018年 | 116篇 |
2017年 | 115篇 |
2016年 | 189篇 |
2015年 | 285篇 |
2014年 | 338篇 |
2013年 | 471篇 |
2012年 | 502篇 |
2011年 | 493篇 |
2010年 | 310篇 |
2009年 | 318篇 |
2008年 | 452篇 |
2007年 | 443篇 |
2006年 | 432篇 |
2005年 | 416篇 |
2004年 | 440篇 |
2003年 | 402篇 |
2002年 | 369篇 |
2001年 | 158篇 |
2000年 | 154篇 |
1999年 | 162篇 |
1998年 | 84篇 |
1997年 | 66篇 |
1996年 | 60篇 |
1995年 | 61篇 |
1994年 | 64篇 |
1993年 | 59篇 |
1992年 | 112篇 |
1991年 | 85篇 |
1990年 | 86篇 |
1989年 | 77篇 |
1988年 | 86篇 |
1987年 | 61篇 |
1986年 | 75篇 |
1985年 | 66篇 |
1984年 | 56篇 |
1983年 | 57篇 |
1982年 | 39篇 |
1981年 | 32篇 |
1980年 | 35篇 |
1979年 | 38篇 |
1978年 | 34篇 |
1977年 | 30篇 |
1976年 | 24篇 |
1975年 | 21篇 |
1974年 | 26篇 |
排序方式: 共有8406条查询结果,搜索用时 31 毫秒
81.
H Kasukawa M Sugimoto N Oshima R Fujii 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1985,81(2):253-257
Mechanisms controlling pigment movements in the melanophore of the blue damselfish, Chrysiptera cyanea, were studied. Histological observations revealed that the melanophore had three-dimensionally developed processes to envelop overlying small iridophores, and thus participated in the construction of a simple dermal chromatophore unit. Nervous stimulation, catecholamines and melatonin brought about melanosome aggregation in the melanophore. The actions of the nervous stimulation and catecholamines were antagonized by alpha adrenolytic agents. A beta adrenergic agonist, metaproterenol, adenosine and adenine nucleotides, and alpha-MSH acted as pigment-dispersing agents. These results indicate that the melanophore of the present material is controlled quite orthodoxly by adrenergic nerves and endocrines, notwithstanding the fact that it has quite a unique morphology among fish species, and that its motile rate is remarkably high. 相似文献
82.
S Fujii N Nakazono K Ishii C C Lin M M Sheu C W Chen K Fujinaga 《Japanese journal of medical science & biology》1984,37(4):161-169
Adenovirus type 8 (Ad 8) has been the major and important causative agent of epidemic keratoconjunctivitis (EKC). By enzymatic cleavage analysis with five endonucleases, PstI, HindIII, BamHI, SalI and SstI, 27 out of 149 Ad 8 isolates recovered from patients with EKC during the period from July, 1980 to July, 1981 in Kaohsiung, Taiwan, were studied. By cleavage patterns, 27 Ad 8 isolates in Kaohsiung were classified into four subtypes which were found to be different from the subtypes (Ad 8A, Ad 8B) prevalent in Sapporo (1). 相似文献
83.
84.
Large amounts of cysteine proteinase inhibitors were found in bovine colostrum. One had a molecular weight of 90,000, and the other a molecular weight of 10,500. The concentrations of both these inhibitors were highest the day after parturition, and were about one-tenth as much on day 7. The lower molecular weight inhibitor was purified by acid treatment, ammonium sulfate fractionation, gel filtration on Sephadex G-50, CM-Sephadex chromatography and rechromatography on Sephadex G-50. The purified preparation gave a single band on SDS-polyacrylamide gel electrophoresis. This inhibitor contained one tryptophanyl residue and one cystinyl residue, and did not contain a free thiol group. Values obtained for its isoelectric point (pI) were 10.0 and 10.3. This material strongly inhibited cathepsin B, cathepsin H, and papain. the higher molecular weight inhibitor was partially purified. It had a pI of 4.2 and inhibited papain, cathepsin H, and cathepsin B. 相似文献
85.
Identification of a glycoprotein, gp21, of adult T cell leukemia virus by monoclonal antibody 总被引:14,自引:0,他引:14
K Sugamura M Fujii S Ueda Y Hinuma 《Journal of immunology (Baltimore, Md. : 1950)》1984,132(6):3180-3184
A mouse hybridoma cell line producing monoclonal antibody, F10, was established from mice hyperimmunized with cells bearing adult T cell leukemia (ATL) virus (ATLV). F10 antibody reacted with an ATLV structural polypeptide ( gp21 ) with a m.w. of 21,000 that was glycosylated on cell surfaces. The gp21 was expressed on cell surfaces of all ATL-associated antigen (ATLA)-positive human cell lines but not on ATLA-negative cell lines nor peripheral blood leukocytes stimulated with mitogens. The gp21 was also detected with anti-ATLA-positive human serum, and the binding of F10 antibody to ATLA-positive cell surfaces was significantly blocked by pretreatment with anti-ATLA-positive human sera. Double immunofluorescence staining with F10 antibody and anti-ATLA-positive human serum caused co-capping on cell surfaces, which suggests that gp21 co-exists with other ATLV antigens expressed on cell surfaces. Immunoprecipitation studies also suggested that the gp21 is a minor component of the ATLV envelope. 相似文献
86.
Kenji Hayasaka Yoshi Kawamoto Takayoshi Shotake Ken Nozawa 《Primates; journal of primatology》1986,27(1):103-114
We calculated the probability of paternity exclusion (P) in 6 troops of rhesus and Japanese macaques housed in open enclosures and 68 wild troops of Japanese, crab-eating, and toque
macaques using 33 genetic loci which encoded the blood protein variations detected by electrophoretic techniques. In the open
enclosures, especially of rhesus troops, we obtained a fairly high probability of paternity exclusion and succeeded in determining
the fathers of offspring. However, we found significant differences between the observed and calculated probabilities in most
of the troops. These differences were ascribed to a situation whereby the Hardy-Weinberg equilibrium had not been attained
in the troops and/or the numbers of variable loci were too small. In the wild troops of Japanese, crab-eating, and toque macaques,
the means ofP were 0.2274 (0.0192–0.5017), 0.4635 (0.1676–0.7151), and 0.7382 (0.6266–0.7954), respectively. We also estimated the number
of loci needed to determine the fathers of offspring with a probability of 0.8 assuming that ten males were present in the
troop. The estimated number was about 13.5 times, 5 times and 1.8 times the number of loci examined on average in the troops
of Japanese, crab-eating and toque macaques, respectively. This means that determination of most of the fathers of offspring
in wild troops of these macaques, even of toque macaques which have a rather high probability of paternity exclusion, is difficult
so long as we employ only electrophoretic techniques. 相似文献
87.
T Yoshimura T Miyoshi M Imaki T Tamura M Fujii K Matsumoto T Toumiya Y Hori T Nakamura M Tanada 《Acta biologica Hungarica》1986,37(3-4):235-241
Changes in the activity of serum gamma-glutamyl transpeptidase (gamma-GTP) and the percentage of the gamma-GTP fraction in healthy young men given a high carbohydrate diet (480-636 g/day, 80% of the total energy) for 21 days were examined. Serum total gamma-GTP activity showed no significant change in four healthy young volunteers who received high carbohydrate diet for 21 days. However, the percentage of the gamma-GTP (1) fraction increased significantly (P less than 0.01) from the basal level of 55.6 +/- 4.0% to 67.6 +/- 0.9% on day 10, and then decreased to 58.4 +/- 1.4% on day 21. When the experimental diet was replaced by usual diet, the percentage of the gamma-GTP (1) fraction returned to the same level as before the experiment. It is concluded from the results that the nutrient intake affects the percentage of gamma-GTP (1), but not the total serum gamma-GTP activity. 相似文献
88.
Yoshiya Shigematsu Ken Tsukahara Tomoaki Tanaka Michio Takeuchi Dr. Eiji Ichishima 《Current microbiology》1986,13(1):43-46
The molecular properties, such as molecular weight, N-and C-terminal amino acids, amino acid composition, and circular dichroism, of 1,2--mannosidase isolated from the culture filtrate ofAspergillus saitoi were determined.The enzyme had aK
m of 0.67 mM andk
cat of 1.27/s with mannobiose at pH 50.0 and 30°C. The anomeric configuration of the reaction products of the enzyme was examined by studying the -anomer. A single Manl2Man linkage in intact Taka-amylase A fromAspergillus oryzae was hydrolyzed, producing free mannose. 相似文献
89.
90.
The effects of numerous ionophores and inhibitors were tested on methane synthesis, intracellular ATP and potassium concentrations, and the proton motive force of the methanogenic archaebacterium Methanobacterium bryantii. M. bryantii had an internal pH near 6.8 (and hence little ΔpH during growth) with an electrical potential of ?127 mV in growth medium and ?105 mV in a pH 6.5 buffer. The study has identified agents which, in M. bryantii, can effectively cause a decline of intracellular ATP (gramicidin, acetylene) and potassium concentrations (gramicidin, nigericin), inhibit methane synthesis (acetylene, gramicidin, nigericin, triphenylmethylphosphonium bromide), eliminate the electrical potential (high extracellular potassium ion concentrations), and dissipate artificially imposed, inside alkaline, pH gradients (monensin, nigericin, carbonyl cyanide m-chlorophenylhydrazone). Carbonyl cyanide m-chlorophenylhydrazone was generally ineffective in media or buffers reduced with cysteine-sulfide but could be effective in cysteine-free solutions reduced with hydrogen sulfide. 相似文献