全文获取类型
收费全文 | 276篇 |
免费 | 30篇 |
国内免费 | 32篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 15篇 |
2014年 | 13篇 |
2013年 | 17篇 |
2012年 | 25篇 |
2011年 | 24篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 13篇 |
2003年 | 6篇 |
2002年 | 12篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1967年 | 4篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1957年 | 2篇 |
1955年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有338条查询结果,搜索用时 15 毫秒
331.
Erythrocytes were settled from whole blood in standard 200 x 2.5 mm erythrocyte settling rate tubes placed vertically and at various angles from 85 degrees to 15 degrees from the horizontal. In all cases sedimentation rates measured along the slope increased with decreasing angle from the horizontal. Vertical settled distances rapidly increased down to an angle of 70 degrees and then changed very little even down to angles as shallow as 30 degrees. Evidence is presented that convection plays a significant role in the inclined settling of erythrocytes, as has already been demonstrated with clay, or glass bead suspensions in water. Inclined settling enhancements obtained are quite similar to those observed under similar conditions with yeast cells in aqueous glucose. 相似文献
332.
333.
The seasonal dynamics of the accumulation, distribution andredistribution of dry matter and 12 mineral nutrients by a weedyspecies of gladiolus (Gladiolus caryophyllaceus) were studiedat Perth, Western Australia, where it has colonized the nutrient-poorsandy soils. Parent corms sprouted in autumn, and the plantshad completed their growth cycle by early summer. The maturereplacement corm had 15-25% of the plant's P, Ca, Na, Zn andCu, 5-15% of its K, N, Cl, Mg, S and dry matter, and < 5%of its Fe and Mn. Seeds had 26% of the plant's dry matter, 60%of its N and P, 21-33% of its S, Mg, Cu and K, 5-20% of itsFe, Mn and Zn, and < 5% of its Ca and Na. The mature vegetativeshoot had 47% of the plant's dry matter and over 40% of eachnutrient, except for N, P and Cu. Phosphorus, K and N were redistributedfrom the parent corm with over 85% efficiency, S, Mg, Zn andCu with 60-70% efficiency, but there was < 10% redistributionof Ca, Na, Cl, Fe and Mn. The efficiency of redistribution fromthe leafy shoot was over 70% for N and P, 29-52% for K, Mg andCu, 16-20% for S, Zn and Cl, but negligible for Ca, Na, Fe andMn. Redistribution from the shoot could have provided the replacementcorm and seeds with 53-98% of their Cu, Mg, N, P and K, and29-38% of their S, Zn and dry matter. Seeds contained over 60%of each nutrient in a capsule, except for Ca, Na and Fe. Redistributionfrom the capsule walls could have provided 13-19% of the P,Cu and Zn, and 3-7% of the N, K, Mg and dry matter accumulatedby seeds. Each plant produced an average of 520 seeds. Removalof flowers and buds at first anthesis resulted in a larger replacementcorm containing a greater quantity of most nutrients, indicatingcompetition between the replacement corm and seeds for nutrients.Redistribution from parent to replacement cormlets in the absenceof shoot and root development was high, with over 50% of thedry matter and each nutrient, except for Ca, being transferred.Concentration of nutrients were low in all organs of G. caryophyllaceus,especially the replacement corm. It was concluded that the effectiveredistribution of key nutrients, such as N and P, to reproductivestructures and tolerance of low internal concentrations of nutrientscontribute to the capacity of G. caryophyllaceus to colonizeand persist on infertile soils.Copyright 1993, 1999 AcademicPress Gladiolus caryophyllaceus, corm, distribution, dry matter, gladiolus, mineral nutrients, nutrient accumulation, nutrient redistribution, seasonal growth, weed 相似文献
334.
Economic Botany - This poisonous drug, formerly available only from Europe, India and the Sudan but now produced also in the United States to the extent of 80,000 pounds annually, has been used... 相似文献
335.
336.
337.
338.