全文获取类型
收费全文 | 5881篇 |
免费 | 391篇 |
国内免费 | 1篇 |
专业分类
6273篇 |
出版年
2022年 | 36篇 |
2021年 | 51篇 |
2020年 | 32篇 |
2019年 | 48篇 |
2018年 | 71篇 |
2017年 | 69篇 |
2016年 | 112篇 |
2015年 | 161篇 |
2014年 | 184篇 |
2013年 | 370篇 |
2012年 | 313篇 |
2011年 | 331篇 |
2010年 | 195篇 |
2009年 | 215篇 |
2008年 | 298篇 |
2007年 | 291篇 |
2006年 | 305篇 |
2005年 | 262篇 |
2004年 | 298篇 |
2003年 | 294篇 |
2002年 | 318篇 |
2001年 | 134篇 |
2000年 | 137篇 |
1999年 | 117篇 |
1998年 | 79篇 |
1997年 | 61篇 |
1996年 | 70篇 |
1995年 | 58篇 |
1994年 | 49篇 |
1993年 | 61篇 |
1992年 | 118篇 |
1991年 | 115篇 |
1990年 | 89篇 |
1989年 | 90篇 |
1988年 | 89篇 |
1987年 | 55篇 |
1986年 | 54篇 |
1985年 | 55篇 |
1984年 | 53篇 |
1983年 | 44篇 |
1982年 | 57篇 |
1981年 | 41篇 |
1980年 | 32篇 |
1979年 | 58篇 |
1978年 | 33篇 |
1977年 | 38篇 |
1976年 | 26篇 |
1975年 | 30篇 |
1974年 | 32篇 |
1972年 | 24篇 |
排序方式: 共有6273条查询结果,搜索用时 15 毫秒
991.
The effects of the immunosuppressive agents FK506 (tacrolimus) and cyclosporin (CyA) on Candida albicans infection in mice
were compared with those of cyclophosphamide. FK506 and CyA did not exacerbate C. albicans infection in mice when the effects
were determined on the basis of survival ratio and colony forming units (CFU) in the kidney, although cyclophosphamide (CY)
impaired the host defence mechanisms of mice against C. albicans infection. The effects of FK506 and CyA on the body weight
of mice, histopathological changes of lymphoid tissues and formation of granulomas in kidney were also studied in comparison
with those of CY.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
992.
Shinji Hama Ayumi Yoshida Kazunori Nakashima Hideo Noda Hideki Fukuda Akihiko Kondo 《Applied microbiology and biotechnology》2010,87(2):537-543
The cell surface engineering system, in which functional proteins are genetically displayed on microbial cell surfaces, has
recently become a powerful tool for applied biotechnology. Here, we report on the surfactant modification of surface-displayed
lipase to improve its performance for enzymatic synthesis reactions. The lipase activities of the surfactant-modified yeast
displaying Rhizopus oryzae lipase (ROL) were evaluated in both aqueous and nonaqueous systems. Despite the similar lipase activities of control and
surfactant-modified cells in aqueous media, the treatment with nonionic surfactants increased the specific lipase activity
of the ROL-displaying yeast in n-hexane. In particular, the Tween 20-modified cells increased the cell surface hydrophobicity significantly among a series
of Tween surfactants tested, resulting in 8–30 times higher specific activity in organic solvents with relatively high log
P values. The developed cells were successfully used for the enzymatic synthesis of phospholipids and fatty acid methyl esters
in n-hexane, whereas the nontreated cells produced a significantly low yield. Our results thus indicate that surfactant modification
of the cell surface can enhance the potential of the surface-displayed lipase for bioconversion. 相似文献
993.
Yamada T Yamada Y Okano Y Terashima T Yokogoshi H 《The Journal of nutritional biochemistry》2009,20(12):948-955
We demonstrated the effects of short- and long-term administration of cacao mass on anxiety in the elevated T-maze test, which is an animal model of anxiety. In the first study, we administered cacao mass (100 mg/100 g body weight) per os and immediately performed the elevated T-maze test. Short-term cacao mass significantly abolished delayed avoidance latency compared with the control but did not change escape latency. This result suggested that cacao mass administration reduced conditional fear-relating behavior. Short-term cacao mass administration did not affect the concentration of brain monoamines, emotion-related neurotransmitters such as norepinephrine, serotonin and dopamine, in the rat brain. In the next study, we fed a cacao mass-containing diet to rats for 2 weeks and performed the elevated T-maze test. Contrary to short-term administration, chronic consumption of cacao mass tended to increase avoidance latency and did not change escape latency. Brain serotonin concentration and its turnover were enhanced by chronic consumption of cacao mass. These results suggested that chronic consumption of cacao did not affect fear-related behavior but was involved in brain monoamine metabolism. In conclusion, we suggest that short-term cacao mass consumption showed an anxiolytic effect but chronic consumption did not. 相似文献
994.
CRUMPLED LEAF (CRL) homologs of Physcomitrella patens are involved in the complete separation of dividing plastids 总被引:1,自引:0,他引:1
Sugita C Kato Y Yoshioka Y Tsurumi N Iida Y Machida Y Sugita M 《Plant & cell physiology》2012,53(6):1124-1133
Plastid division is controlled by numerous nuclear genes. Arabidopsis thaliana CRUMPLED LEAF (AtCRL) is a plastid division-related gene, and the crl mutant exhibits a dwarf phenotype with abnormal cell division and a significant reduction in plastid numbers. However, the function of AtCRL is not fully understood. Here, we identified and characterized two AtCRL homologs, PpCRL1 and PpCRL2, in the moss Physcomitrella patens. PpCRL1 and PpCRL2 shared 77% amino acid identity with each other and 47% identity with AtCRL. Single PpCRL1 or -2 gene knockout (KO) mutants could not be distinguished from the wild-type mosses, but PpCRL1 and -2 double KO mutants displayed growth retardation of protonemata and gametophores and harbored approximately 10 large chloroplasts per cell. This indicates that PpCRL1 and PpCRL2 have redundant functions in chloroplast division and plant growth. Unlike the A. thaliana crl mutants, however, the PpCRL double KO mutants did not display abnormal orientation of the cell division plane. Complementation experiments showed that AtCRL partially rescued the defects in chloroplast size and number of the PpCRL double KO mutant. This suggests that PpCRL has a similar, but not identical, function to AtCRL. Time-lapse microscopic observation of the double PpCRL KO mutants revealed that some dumbbell-shaped chloroplasts failed to complete division at the late stage of plastid division; enlarged chloroplasts were thus generated. This strongly suggests that PpCRLs are involved in the complete separation of dividing chloroplasts. 相似文献
995.
Yota Tsuge Yoshimi Hori Motonori Kudou Jun Ishii Tomohisa Hasunuma Akihiko Kondo 《Applied microbiology and biotechnology》2014,98(20):8675-8683
The toxic fermentation inhibitors in lignocellulosic hydrolysates raise serious problems for the microbial production of fuels and chemicals. Furfural is considered to be one of the most toxic compounds among these inhibitors. Here, we describe the detoxification of furfural in Corynebacterium glutamicum ATCC13032 under both aerobic and anaerobic conditions. Under aerobic culture conditions, furfuryl alcohol and 2-furoic acid were produced as detoxification products of furfural. The ratio of the products varied depending on the initial furfural concentration. Neither furfuryl alcohol nor 2-furoic acid showed any toxic effect on cell growth, and both compounds were determined to be the end products of furfural degradation. Interestingly, unlike under aerobic conditions, most of the furfural was converted to furfuryl alcohol under anaerobic conditions, without affecting the glucose consumption rate. Both the NADH/NAD+ and NADPH/NADP+ ratio decreased in the accordance with furfural concentration under both aerobic and anaerobic conditions. These results indicate the presence of a single or multiple endogenous enzymes with broad and high affinity for furfural and co-factors in C. glutamicum ATCC13032. 相似文献
996.
Tohru Tanigawa Rei Shibata Kazuhisa Kondo Nobuyuki Katahira Takahiro Kambara Yoko Inoue Hiroshi Nonoyama Yuichiro Horibe Hiromi Ueda Toyoaki Murohara 《PloS one》2015,10(9)
Obesity-related complications are associated with the development of age-related hearing impairment. β-Conglycinin (β-CG), one of the main storage proteins in soy, offers multiple health benefits, including anti-obesity and anti-atherosclerotic effects. Here, to elucidate the potential therapeutic application of β-CG, we investigated the effect of β-CG on age-related hearing impairment. Male wild-type mice (age 6 months) were randomly divided into β-CG-fed and control groups. Six months later, the body weight was significantly lower in β-CG-fed mice than in the controls. Consumption of β-CG rescued the hearing impairment observed in control mice. Cochlear blood flow also increased in β-CG-fed mice, as did the expression of eNOS in the stria vascularis (SV), which protects vasculature. β-CG consumption also ameliorated oxidative status as assessed by 4-HNE staining. In the SV, lipofuscin granules of marginal cells and vacuolar degeneration of microvascular pericytes were decreased in β-CG-fed mice, as shown by transmission electron microscopy. β-CG consumption prevented loss of spiral ganglion cells and reduced the frequencies of lipofuscin granules, nuclear invaginations, and myelin vacuolation. Our observations indicate that β-CG ameliorates age-related hearing impairment by preserving cochlear blood flow and suppressing oxidative stress. 相似文献
997.
Ichinose M Saito M Kondo N Nishiyasu T 《American journal of physiology. Heart and circulatory physiology》2006,290(4):H1419-H1426
We investigated the time-dependent modulation of arterial baroreflex (ABR) control of muscle sympathetic nerve activity (MSNA) that occurs during isometric handgrip exercise (IHG). Thirteen healthy subjects performed a 3-min IHG at 30% maximal voluntary contraction, which was followed by a period of imposed postexercise muscle ischemia (PEMI). The ABR control of MSNA (burst incidence and strength and total activity) was evaluated by analyzing the relationship between spontaneous variations in diastolic arterial pressure (DAP) and MSNA during supine rest, at each minute of IHG, and during PEMI. We found that 1) the linear relations between DAP and MSNA variables were shifted progressively rightward until the third minute of IHG (IHG3); 2) 2 min into IHG (IHG2), the DAP-MSNA relations were shifted upward and were shifted further upward at IHG3; 3) the sensitivity of the ABR control of total MSNA was increased at IHG2 and increased further at IHG3; and 4) during PEMI, the ABR operating pressure was slightly higher than at IHG2, and the sensitivity of the control of total MSNA was the same as at IHG2. During PEMI, the DAP-burst strength and DAP-total MSNA relations were shifted downward from the IHG3 level to the IHG2 level, whereas the DAP-burst incidence relation remained at the IHG3 level. These results indicate that during IHG, ABR control of MSNA is modulated in a time-dependent manner. We suggest that this modulation of ABR function is one of the mechanisms underlying the progressive increase in blood pressure and MSNA during the course of isometric exercise. 相似文献
998.
Glycoconjugate Journal - Glycogen debranching enzyme (GDE) is bifunctional in that it exhibits both 4-α-glucanotransferase and amylo-α-1,6-glucosidase activity at two distinct catalytic... 相似文献
999.
Yumura S Ueda M Sako Y Kitanishi-Yumura T Yanagida T 《Traffic (Copenhagen, Denmark)》2008,9(12):2089-2099
Total internal reflection fluorescence microscopy revealed how individual bipolar myosin II filaments accumulate at the equatorial region in dividing Dictyostelium cells. Direct observation of individual filaments in live cells provided us with much convincing information. Myosin II filaments accumulated at the equatorial region by at least two independent mechanisms: (i) cortical flow, which is driven by myosin II motor activities and (ii) de novo association to the equatorial cortex. These two mechanisms were mutually redundant. At the same time, myosin II filaments underwent rapid turnover, repeating their association and dissociation with the actin cortex. Examination of the lifetime of mutant myosin filaments in the cortex revealed that the turnover mainly depended on heavy chain phosphorylation and that myosin motor activity accelerated the turnover. Double mutant myosin II deficient in both motor and phosphorylation still accumulated at the equatorial region, although they displayed no cortical flow and considerably slow turnover. Under this condition, the filaments stayed for a significantly longer time at the equatorial region than at the polar regions, indicating that there are still other mechanisms for myosin II accumulation such as binding partners or stabilizing activity of filaments in the equatorial cortex. 相似文献