全文获取类型
收费全文 | 2262篇 |
免费 | 161篇 |
出版年
2021年 | 28篇 |
2020年 | 18篇 |
2019年 | 26篇 |
2018年 | 34篇 |
2017年 | 26篇 |
2016年 | 42篇 |
2015年 | 58篇 |
2014年 | 85篇 |
2013年 | 145篇 |
2012年 | 129篇 |
2011年 | 113篇 |
2010年 | 73篇 |
2009年 | 52篇 |
2008年 | 96篇 |
2007年 | 117篇 |
2006年 | 100篇 |
2005年 | 94篇 |
2004年 | 88篇 |
2003年 | 87篇 |
2002年 | 77篇 |
2001年 | 59篇 |
2000年 | 96篇 |
1999年 | 57篇 |
1998年 | 22篇 |
1997年 | 15篇 |
1996年 | 19篇 |
1995年 | 21篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 56篇 |
1991年 | 55篇 |
1990年 | 54篇 |
1989年 | 57篇 |
1988年 | 52篇 |
1987年 | 32篇 |
1986年 | 34篇 |
1985年 | 27篇 |
1984年 | 30篇 |
1983年 | 25篇 |
1982年 | 19篇 |
1981年 | 12篇 |
1980年 | 16篇 |
1979年 | 20篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1971年 | 10篇 |
1969年 | 12篇 |
1968年 | 11篇 |
1967年 | 11篇 |
1966年 | 11篇 |
排序方式: 共有2423条查询结果,搜索用时 15 毫秒
1.
2.
Hiroyuki Kozu Isao Kobayashi Mitsutoshi Nakajima Kunihiko Uemura Seigo Sato Sosaku Ichikawa 《Food biophysics》2010,5(4):330-336
This paper uses computational fluid dynamics to simulate and analyze intragastric fluid motions induced by human peristalsis.
We created a two-dimensional computational domain of the distal stomach where peristalsis occurs. The motion of the gastric
walls induced by an antral contraction wave (ACW) on the wall of the computational domain was well simulated using a function
defined in this study. Retropulsive flow caused by ACW was observed near the occluded region, reaching its highest velocity
of approximately 12 mm/s in the narrowest region. The viscosity of the model gastric contents applied in this study hardly
affected the highest velocity, but greatly affected the velocity profile in the computational domain. The shear rate due to
gastric fluid motion was calculated using the numerical output data. The shear rate reached relatively high values of approximately
20 s−1 in the most occluded region. The shear rate profile was almost independent of the fluid viscosity. We also simulated mass
transfer of a gastric digestive enzyme (pepsin) in model gastric content when peristalsis occurs on the gastric walls. The
visualized simulation results suggest that gastric peristalsis is capable of efficiently mixing pepsin secreted from the gastric
walls with an intragastric fluid. 相似文献
3.
Keisuke Hanaki Tomonori Matsuo Michihiko Nagase 《Biotechnology and bioengineering》1981,23(7):1591-1610
The inhibitory effect of long-chain fatty acids on the anaerobic digestion process was examined in batch experiments using synthetic substrates. The addition of long-chain fatty acids caused the appearance of the appearance of the lag period in the methane production from acetate and in the degradation of both long-chain fatty acids and n-butyrate. Methane production from hydrogen proceeded without lag period although its rate was lowered. Fermentation of glucose was not inhibited. Neutral fat in the whole milk was easily hydrolyzed to long-chain fatty acids, which brought about the inhibition. The addition of calcium chloride reduced the inhibitory effect of long-chain fatty but it did not do so after the culture had been exposed to long-chain fatty acids for more than several hours. The addition of calcium carbonate could not reduce the inhibition because of its insolubility. 相似文献
4.
5.
S Ogita M Imanaka T Takebayashi Y Nakai H Fukumasu S Matsuo M Matsumoto B Tanaka K Iwanaga 《The Annals of physiological anthropology》1990,9(2):93-98
For the purpose of determining the most reasonable lying posture for pregnant women, we investigated the lying positions of both 247 non-pregnant women and 302 pregnant women during sleep. As for the rate of each position during the entire period of observation, 33.2% of the non-pregnant women were in the supine position, 41.2% in the lateral position, 18.4% in Sims' position and 7.1% in the prone position. In the pregnant group, the rate of supine position, simple lateral position and Sims' position was 34.2%, 52.2% and 12.7%, respectively, but the rate of the prone position was limited to 0.8%. All of the gravidas assuming the prone position were at less than 16 weeks of gestation. Non-pregnant women could sleep in a variety of positions, but pregnant women could assume the prone position during sleep only in the stage when the abdomen is not yet prominent or distended. Pregnant women were restricted significantly, either consciously or unconsciously, with progress in gestation. 相似文献
6.
7.
Unique distributions of natriuretic hormones in dog brain 总被引:1,自引:0,他引:1
N Fujio M Ohashi H Nawata K Kato J Tateishi H Matsuo H Ibayashi 《Regulatory peptides》1987,18(3-4):131-137
We examined the regional distributions of atrial natriuretic polypeptide (ANP) and digoxin-like immunoreactivity (DLI) in dog brain, using specific radioimmunoassay. The molecular form of the dog brain ANP was similar to that of alpha-hANP, in gel filtration and reversed-phase HPLC. Distribution of ANP in dog brain differed from rat brain. A significant amount of ANP-like immunoreactivity (ANPLI) was observed in the periaqueductal grey, ventral thalamus and spinal cord, however, only a trace amount was seen in the hypothalamus. The DLI was widely distributed in the dog brain, especially with over 2 ng/g wet wt. of the immunoreactivity content in mammillary body, septum, striatal body, hypothalamus and periaqueductal grey. Different from the localizations of natriuretic hormones in rat brain, the periaqueductal grey matter in dog brain may be an important source of both natriuretic hormones. 相似文献
8.
Summary Specific granules in porcine hearts were observed in atrial cardiocytes, Purkinje fibers, and transitional cells of the ventricle. These granule-containing cells were immunohistochemically stained by applying the avidin-biotin-peroxidase complex method using an antiserum against -human atrial natriuretic polypeptide (ANP). Immunoelectron microscopy of sections stained using the immunogold method indicated that these specific granules are storage sites of ANP. Furthermore, an impulse-conducting system consisting of immunoreactive cells was clearly distinguishable from nonimmunoreactive ventricular cardiocytes. We conclude that specific-granule-containing cells, i.e., ANP-producing cells, are located in both the atrial walls and the ventricular impulse-conducting system. The presence of ANP may be correlated with impulse conduction. 相似文献
9.
R Sakakibara Y Horio M Ishiguro K Kangawa H Matsuo H Wada 《Biochemical and biophysical research communications》1987,148(3):979-988
A peptide (extra signal peptide) comprising amino acids 1-29 of pig liver pre-mitochondrial aspartate aminotransferase (p-mAAT) was synthesized chemically. The peptide was found to block the import of rat liver p-mAAT into rat liver mitochondria. An antibody raised against the peptide immunoprecipitated rat liver p-mAAT synthesized in a rabbit reticulocyte cell-free translation system. These results suggested that the extra signal peptide sequence of p-mAAT is essential for import of p-mAAT into the mitochondria and that there is structural homology between the extra signal peptides of pig and rat liver p-mAAT. An anti-idiotypic antibody against the peptide was also prepared and purified by affinity chromatography on an Affi-Gel 10 anti-peptide IgG column and was then characterized. 相似文献
10.
Enzyme immobilization in the form of fiber and paper was easily achieved by wet spinning of aqueous admixture of sodium alginate and enzymes into divalent metallic ion solution as a coagulating bath, followed by paper making of resultant shortly cut fibers. Entrapment yields of enzymes used, e.g., glucoamylase, cyclodextrin glucanotransferase, endo-polygalacturonase, and protease, were always higher in calcium alginate fibers and their papers than those in corresponding beads. It was found that the yields increased with an increase of the discharge rate through the spinning nozzle because the higher discharge rate could provide more highly oriented metal-chelate linear polymer molecules along the fiber axis for preventing leakage of entrapped enzymes. Divalent metallic ions affected greatly the entrapment of glucoamylase in alginate fibers, the order of which followed roughly the ionotropic series of Thiele. Entrapment of glucoamylase in bicomponent systems comprising alginate and other water-soluble polymers was also investigated. 相似文献