全文获取类型
收费全文 | 5339篇 |
免费 | 282篇 |
国内免费 | 1篇 |
专业分类
5622篇 |
出版年
2023年 | 38篇 |
2021年 | 64篇 |
2020年 | 53篇 |
2019年 | 73篇 |
2018年 | 212篇 |
2017年 | 177篇 |
2016年 | 203篇 |
2015年 | 145篇 |
2014年 | 233篇 |
2013年 | 402篇 |
2012年 | 409篇 |
2011年 | 444篇 |
2010年 | 289篇 |
2009年 | 173篇 |
2008年 | 163篇 |
2007年 | 135篇 |
2006年 | 143篇 |
2005年 | 55篇 |
2004年 | 53篇 |
2003年 | 63篇 |
2002年 | 49篇 |
2001年 | 51篇 |
2000年 | 57篇 |
1999年 | 62篇 |
1998年 | 54篇 |
1997年 | 51篇 |
1996年 | 51篇 |
1995年 | 58篇 |
1994年 | 50篇 |
1993年 | 38篇 |
1992年 | 51篇 |
1991年 | 69篇 |
1988年 | 50篇 |
1987年 | 42篇 |
1985年 | 61篇 |
1984年 | 50篇 |
1983年 | 61篇 |
1982年 | 57篇 |
1981年 | 63篇 |
1980年 | 52篇 |
1979年 | 51篇 |
1978年 | 45篇 |
1976年 | 49篇 |
1975年 | 49篇 |
1974年 | 47篇 |
1972年 | 50篇 |
1970年 | 40篇 |
1969年 | 50篇 |
1968年 | 44篇 |
1967年 | 36篇 |
排序方式: 共有5622条查询结果,搜索用时 15 毫秒
21.
Summary A study of enzymatic equipment of enterochromaffine cells (e.c.) in jenual biopsies obtained with a Crosby capsule in normal humans and patients with nontropical sprue was undertaken. The following enzymes were demonstrated: alkaline phosphatase and adenosine triphosphatase (cell membrane), acid phosphatase (corpuscular), non-specific esterase (diffuse and corpuscular, predominantly eserine resistant, in corpuscular localization E 600 resistant), DPN- and TPN-diaphorases and dehydrogenases of lactic acid, malic acid, isocitric acid, glucoso-6-phosphoric acid, succinic acid, -hydroxybutyric acid and -glycerophosphoric acid. Enzyme activities were not equal in all cells suggesting some type of secretory cycle. In most patients with untreated nontropical sprue or with the disease in relapse e.c. were more numerous and hypertrophic with elevated activities of non-specific esterase and acid phosphatase. Implications of these results are briefly discussed.With 8 Figures in the Text, of which 2 in Colour 相似文献
22.
Antiserum был подготовлен противингибитор вируса haemagglutination (IVH)одна из эмбриона chorioallantoic мембр анныепутем иммун изации морских св инокЭто анти-инги битора в сыворотке заблокирован ингибирование IVH из chorioallantoicмембран в haemagglutination испытанияно ника кого влияния на ре цепторы эритроци товСыворотке кро] ви не влияет рост chorioallantoic мембраны клет ок инет нейтрализ овать воздействи е на вирус гриппа Она снизилась спо собность chorioallantoic мембр ан для adsorb вируса гри ппа, а также степен ь размножения вир усав такого рода тканиАвторы хоте ли бы поблагодари ть г-н Г. Ruttkay-Ne -палубе и для проведения эле ктрофореза меру ния. 相似文献
23.
24.
Seven streptomycete strains were tested for biotransformation of salicylate. The products were identified by nuclear magnetic resonance spectroscopy and three types of conversion were found. Streptomyces cinnamonensis and Streptomyces spectabilis formed gentisate and salicylamide concurrently. Streptomyces rimosus transformed salicylate to salicylamide. Streptomyces lividans, Streptomyces coelicolor, Streptomyces griseus and Streptomyces avermitilis produced only gentisate. Time course studies of salicylate conversion by thin-layer chromatography and high pressure liquid chromatography showed that salicylamide was accumulated in the culture broth, whereas gentisate was further metabolized.Key words: salicylate, gentisate, salicylamide, biotransformation, Streptomyces spp. 相似文献
25.
Cells ofBacillus megaterium contain 35–45% of poly(3-hydroxybutyrate) (PHB) at the beginning of the stationary phase. This amount is only slightly affected
by the medium composition. The PHB granules are spherical with the mean diameter of 1.15 μm. 相似文献
26.
Manganese peroxidase as an extracellular enzyme is produced by the white rot fungusPhanerochœte chrysosporium under nutrient nitrogen or carbon limitation. The effect of nitrogen concentration on the activity of manganese peroxidase
was studied using ammonium nitrate andl-asparagine as nitrogen sources. The highest activity of the enzyme was observed in cultures grown in a medium containing
75 mg/L ammonium nitrate and 0.15 g/Ll-asparagine. Manganese peroxidase was not detectable in cultures grown in the presence 0.5 g/L ammonium nitrate and 1 g/Ll-asparagine. 相似文献
27.
L. Kováč 《Folia microbiologica》1961,6(5):311-318
- (1)Мембраны ненарушенных клеток дрожжей непроницаемы для солей янтарной кислоты и феррицианида, так что в их суспензии не наблюдается сукцинодегидрогеназы с феррикианидом как акцептором электронов. 相似文献
28.
29.
30.
Summary The effects of most frequently used carbohydrates and osmolalities of media on the growth and productivity ofClaviceps purpurea in submerged cultures were investigated. The maximum alkaloid yield was obtained with 20% mannitol as well as with 10% mannitol when 2% NaCl was added to the medium and the osmolality about 1 osmol/kg H2O was established at the end of fermentation. Increased or decreased osmolality of the medium had a negative influence on fungal growth and alkaloid production. Almost the same effect was observed with sucrose as with mannitol, whereas with glucose only maximal growth was achieved. 相似文献