全文获取类型
收费全文 | 417篇 |
免费 | 18篇 |
专业分类
林业 | 23篇 |
农学 | 11篇 |
42篇 | |
综合类 | 26篇 |
农作物 | 15篇 |
水产渔业 | 17篇 |
畜牧兽医 | 246篇 |
园艺 | 2篇 |
植物保护 | 53篇 |
出版年
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 16篇 |
2014年 | 15篇 |
2013年 | 21篇 |
2012年 | 19篇 |
2011年 | 15篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 18篇 |
2007年 | 15篇 |
2006年 | 29篇 |
2005年 | 26篇 |
2004年 | 18篇 |
2003年 | 21篇 |
2002年 | 16篇 |
2001年 | 25篇 |
2000年 | 19篇 |
1999年 | 18篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有435条查询结果,搜索用时 15 毫秒
141.
Higashiyama T Yabe S Sasaki N Nishimura Y Miyagishima S Kuroiwa H Kuroiwa T 《Science (New York, N.Y.)》2001,293(5534):1480-1483
In flowering plants, guidance of the pollen tube to the embryo sac (the haploid female gametophyte) is critical for successful fertilization. The target embryo sac may attract the pollen tube as the final step of guidance in the pistil. We show by laser cell ablation that two synergid cells adjacent to the egg cell attract the pollen tube. A single synergid cell was sufficient to generate an attraction signal, and two cells enhanced it. After fertilization, the embryo sac no longer attracts the pollen tube, despite the persistence of one synergid cell. This cessation of attraction might be involved in blocking polyspermy. 相似文献
142.
Tanii H Higashi T Nishimura F Higuchi Y Saijoh K 《Journal of agricultural and food chemistry》2005,53(23):8993-8996
Little is known about whether glucosinolate-derived nitriles have the ability to increase phase 2 detoxication enzymes and glutathione (GSH) in vivo. In this study, the ability of allyl nitrile, a hydrolysis product of the glucosinolate sinigrin, to increase tissue levels of the phase 2 detoxication enzymes glutathione S-transferase and quinone reductase and GSH in a variety of mouse tissues was examined. At the lowest dose level (11.8 mg/kg/day), allyl nitrile showed inductive ability in the stomach and lungs. At 23.6 mg/kg/day, the inductive effect was observed in the stomach, rectum, urinary bladder, and lungs, whereas at 47.2 mg/kg/day, it was recorded in the stomach, rectum, urinary bladder, kidneys, and lungs. These results show that allyl nitrile displays its maximum potency in the stomach and lungs, which is of interest in light of epidemiological studies demonstrating an inverse association between crucifer intake and the incidence of stomach and lung cancers. 相似文献
143.
Mohsen Mohamed Elsharkawy Mai Nakatani Mitsuyoshi Nishimura Tatsuyuki Arakawa Masafumi Shimizu 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(7):629-636
This study was conducted to evaluate the efficacy of yeast strain TA-2 for controlling rice blast, cabbage black leaf spot, and tomato bacterial wilt diseases. Microscopic and phylogenetic analyses based on rDNA-internal transcribed region (ITS) and rDNA-D1/D2 sequences indicated that yeast strain TA-2 is Meyerozyma guilliermondii. Pretreatment with TA-2 by soil drenching significantly reduced the severity of black leaf spot disease caused by Alternaria brassicicola and leaf blast disease caused by Magnaporthe oryzae. Symptom development of tomato bacterial wilt caused by Ralstonia solanacearum in both soil drench and needle inoculation tests was significantly reduced in TA-2-pretreated plants under soil drenching. Disease severity and R. solanacearum growth were significantly reduced in tomato plants pretreated with yeast culture, cell suspension, or culture filtrate of TA-2 under soil drenching. TA-2 does not produce antibiotics. The present study indicates that disease suppression is systemic, as the roots were treated with TA-2 and the pathogens were inoculated onto leaves or stems, thereby separating the two spatially. M. guilliermondii TA-2 could become a promising natural antimicrobial agent against rice blast, cabbage black leaf spot, and tomato bacterial wilt diseases and might be useful as an eco-friendly control measure, contributing to sustainable agriculture. 相似文献
144.
145.
146.
Ryohei Suzuki Hirotaka Matsumoto Takahiro Teshima Hidekazu Koyama 《Journal of Veterinary Cardiology》2013,15(1):41-49
ObjectiveThe objective of this study was to clinically assess myocardial deformations in dogs with chronic mitral valve insufficiency (CMVI) using two-dimensional speckle-tracking echocardiography (2D-STE).Animals87 dogs with CMVI.MethodsDogs were placed into 1 of 3 classes, based on the International Small Animal Cardiac Health Council classification. In addition, 20 weight- and age-matched healthy dogs were enrolled as controls. The dogs were examined for myocardial deformations using 2D-STE, and strain and strain rate in the longitudinal, circumferential, and radial directions were evaluated.ResultsClass II and III dogs had higher circumferential strain than class I dogs (P = 0.002 and P = 0.001, respectively) and controls (P < 0.001 and P < 0.001, respectively). Class III dogs had higher radial strain than class I dogs (P = 0.001) and controls (P < 0.001). Class III dogs had higher radial strain rate than class I dogs (P = 0.006) and controls (P = 0.001). Other deformations, including longitudinal deformations, were not significantly different between classes of CMVI or between CMVI dogs and controls.ConclusionsIn the clinical progression of CMVI in dogs, myocardial deformations, as assessed by 2D-STE, differed according to myocardial contractile direction. Thus, assessments of multidirectional myocardial deformations may be important for better assessment of clinical cardiac function in dogs with CMVI. 相似文献
147.
Ryohei Suzuki Hirotaka Matsumoto Takahiro Teshima Hidekazu Koyama 《Journal of Veterinary Cardiology》2013,15(4):243-252
ObjectivesThe objective of this study was to evaluate the effect of age on myocardial function assessed by two-dimensional speckle-tracking echocardiography (2D-STE) in healthy dogs.AnimalsThirty-two healthy Beagles were used.MethodsMyocardial function was assessed in each dog by using 2D-STE, and the results were compared between young and old dogs.ResultsThe myocardial deformations in systole, besides the apical rotation rate, were not significantly different between young and old dogs. In contrast, the early diastolic circumferential strain rate, basal rotation rate, and torsion rate were significantly lower in old dogs than in young dogs (P = 0.03, P = 0.033, and P = 0.015, respectively). Late diastolic longitudinal and radial strain rates were significantly higher in old dogs than in young dogs (P = 0.002 and P = 0.018, respectively).ConclusionsYoung and old dogs showed similar systolic myocardial deformations, but significant differences in the values of some diastolic deformation variables were found between young and old dogs, highlighting the need for using age-matched control subjects in studies of diastolic function. 相似文献
148.
Minami W. OKUYAMA Michito SHIMOZURU Go ABE Mariko NAKAI Mariko SASHIKA Ken-Ichiro SHIMADA Nobuhiro TAKAHASHI Daisuke FUKUI Ryohei NAKAMURA Toshio TSUBOTA 《The Journal of reproduction and development》2013,59(4):361-367
The raccoon (Procyon lotor), indigenous to North America, has
naturalized in Japan as an invasive alien species, having been introduced into the country
in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been
increasing in number and spreading throughout the island. The age at the onset of puberty
for raccoons is important for estimating individual lifetime reproductive success and
population growth. The present study investigated the timing of and potential factors
affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and
histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For
the majority of feral yearling raccoons, prepubertal development began in May, and
spermatozoa production began in October prior to their second mating season. However, some
larger juveniles attained puberty during the juvenile period. The captive juvenile, which
was fed throughout the winter, attained puberty only 11 months after birth. These results
suggest that if male raccoons can achieve enough body growth before the first mating
season, puberty can be attained early. In both juveniles and yearlings, spermatozoa
production was only observed after autumn. This timing coincided with the recrudescence of
seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male
raccoons appears to require both adequate body nutrient development and several
environmental factors that control seasonal testicular changes. 相似文献
149.
This study evaluated the effect of 13 years of swine‐manure application on the changes in soil hydraulic properties, and as associated physicochemical properties, with a focus on heavy metal mobility. Various soil hydraulic properties were measured, including soil water retention (SWR), saturated field hydraulic conductivity (Kfs) and unsaturated field hydraulic conductivity (Kfunsat) using a disc infiltrometer. Heavy metal mobility was evaluated with a sequential extraction procedure. At 0–30 cm soil depth in the heavily manured plot (SMhigh plot), SWR at 0 to ?100 kPa was significantly larger than in plots amended with a standard amount of manure (SMstd plot) or with chemical fertilizer (CF plot). Kfs and Kfunsat values in both manure‐amended plots were less than in the CF plot under dry soil conditions but greater than those of the CF plot under wet soil conditions. Furthermore, Kfs and Kfunsat did not necessarily increase with manure application rates. On the other hand, high‐mobility metal fractions, such as the exchangeable fraction of Zn, and the CH3CO2Na‐extractable fraction of Zn and Mn, and the metal–organic complex fractions of Zn, Cu and Mn, increased with the greater manure application rate. In addition, low‐mobility metal fractions, the organically bound fractions of Zn, Cu and Mn in the high SM plot and the easily reducible metal oxide fraction of Mn in both manure‐amended plots were probably affected and released into high‐mobility fractions. This indicated that manure application changed the soil redox conditions by improving the soil structure, depending on the water content of soil pores. Despite the reduction of Kfs and Kfunsat by heavy manure application, the transport of high‐mobility metal fractions with either surface water flow or infiltration water flow could be controlled by soil water content at the beginning of a rain or irrigation event. 相似文献
150.
Guang-Xi Wang Toshiyuki Imaizumi Wei Li Hiromasa Saitoh Ryohei Terauchi Takanori Ohsako Tohru Tominaga 《Pesticide biochemistry and physiology》2008,92(1):24-29
TILLING (Targeting Induced Local Lesions IN Genomes) is a low-cost, high-throughput reverse genetic technique that employs a mismatch-specific endonuclease CEL-1 to discover induced point mutations in the genes of interest. The use of the TILLING technique to survey natural variation in genes is called EcoTILLING. Here, we report a modified EcoTILLING method for the discovery of mutations in multigene family, which we coin “Self-EcoTILLING” by using an allotetraploid Monochoria vaginalis ALS multigene family as an example. The mutations could be detected by TILLING of PCR products resulting from the primers specific to both Als1 and Als3 without involving the experimental step of mixture of reference and query DNA. Either of the two co-amplified loci could serve as reference DNA to the other. We demonstrate with this example that Self-EcoTILLING is a fast, reliable and economical technique of detecting single-nucleotide mutations in polyploid plants containing multigene family. 相似文献