全文获取类型
收费全文 | 1048篇 |
免费 | 54篇 |
专业分类
林业 | 36篇 |
农学 | 35篇 |
基础科学 | 21篇 |
148篇 | |
综合类 | 88篇 |
农作物 | 37篇 |
水产渔业 | 72篇 |
畜牧兽医 | 593篇 |
园艺 | 11篇 |
植物保护 | 61篇 |
出版年
2021年 | 9篇 |
2020年 | 12篇 |
2019年 | 25篇 |
2018年 | 14篇 |
2017年 | 16篇 |
2016年 | 19篇 |
2015年 | 19篇 |
2014年 | 19篇 |
2013年 | 54篇 |
2012年 | 27篇 |
2011年 | 47篇 |
2010年 | 25篇 |
2009年 | 32篇 |
2008年 | 55篇 |
2007年 | 59篇 |
2006年 | 38篇 |
2005年 | 44篇 |
2004年 | 38篇 |
2003年 | 31篇 |
2002年 | 39篇 |
2001年 | 30篇 |
2000年 | 30篇 |
1999年 | 33篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 12篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 11篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 19篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 7篇 |
1975年 | 14篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1971年 | 11篇 |
1969年 | 11篇 |
1967年 | 8篇 |
排序方式: 共有1102条查询结果,搜索用时 15 毫秒
1.
A haematological disorder in a dog characterised by a massive leucocytosis, mainly composed of eosinophils and their precursors is reported here. The normal composition of cells in the bone marrow was displaced in favour of the eosinophils and their precursors. No apparent cause for the pronounced eosinophilia could be determined by clinical, haematological, clinical-chemical, radiological or pathological examinations. A diagnosis of eosinophilic leukaemoid reaction was suggested as the criteria for the diagnosis of eosinophilic leukaemia in the dog but this was not firmly established. 相似文献
2.
3.
Sv. Jensen Storch 《Journal of pest science》1933,9(4):48-50
Ohne Zusammenfassung
Mit 1 Abbildung. 相似文献
4.
5.
6.
7.
8.
C. R. Jensen 《Irrigation Science》1982,3(2):111-121
Summary Barley plants (Hordeum distichum, L., cv. Zita) grown in a sandy soil in pots were adjusted during a pretreatment period of 5 days to three levels of soil water osmotic potential by percolating 61 of a nutrient solution with additional 0, 22.3 and 44.6 mM KCl. A drying cycle was then started and the plants were harvested when the soil water matric potential had decreased to –1.4 MPa, respectively 6, 7 and 8 days later.No significant differences in dry matter yields, transpiration coefficients and wilting percentages were found between treatments.During the drying cycle leaf water potential (
l
) decreased concomitantly with decrease in soil water potential (
s
) with almost constant and similar differences (
l
–
s
) for all treatments despite differences in levels of potentials. The concomitant decrease in leaf osmotic potential () was due partly to dehydration (58%) and partly to increase in leaf solute content (42%) independent of treatment. The part of total osmotic solutes due to K decreased relatively during the drying cycle.Close relationships were found between and
l
as functions of relative water content (RWC). Identical curves for the two levels of salt treatment agree with similar concentrations of K, Cl, and ash found for salt treated plants indicating that maximum uptake of macro nutrients may have been reached.During the main part of the drying cycle the turgor potential as function of RWC was higher and decreased less steeply with decreasing RWC in the salt treated than in the non-salt treated plants.In the beginning of the drying cycle additions of KCI lowered the transpiration rates of the salt treated plants resulting in a slower desiccation of the soil and hence an increased growth period. A delay in uptake from a limited soil water supply may be advantageous during intermittent periods of drought. 相似文献
9.
10.
Vimal Nair Min Cheol Kim James A. Golen Arnold L. Rheingold Gabriel A. Castro Paul R. Jensen William Fenical 《Marine drugs》2020,18(11)
A new cytotoxic thiodepsipeptide, verrucosamide (1), was isolated along with the known, related cyclic peptide thiocoraline, from the extract of a marine-derived actinomycete, a Verrucosispora sp., our strain CNX-026. The new peptide, which is composed of two rare seven-membered 1,4-thiazepane rings, was elucidated by a combination of spectral methods and the absolute configuration was determined by a single X-ray diffraction study. Verrucosamide (1) showed moderate cytotoxicity and selectivity in the NCI 60 cell line bioassay. The most susceptible cell lines were MDA-MB-468 breast carcinoma with an LD50 of 1.26 µM, and COLO 205 colon adenocarcinoma with an LD50 of 1.4 µM. Also isolated along with verrucosamide were three small 3-hydroxy(alkoxy)-quinaldic acid derivatives that appear to be products of the same biosynthetic pathway. 相似文献