全文获取类型
收费全文 | 4014篇 |
免费 | 226篇 |
国内免费 | 354篇 |
专业分类
林业 | 287篇 |
农学 | 393篇 |
基础科学 | 130篇 |
412篇 | |
综合类 | 1837篇 |
农作物 | 263篇 |
水产渔业 | 105篇 |
畜牧兽医 | 711篇 |
园艺 | 136篇 |
植物保护 | 320篇 |
出版年
2024年 | 21篇 |
2023年 | 95篇 |
2022年 | 143篇 |
2021年 | 172篇 |
2020年 | 151篇 |
2019年 | 177篇 |
2018年 | 126篇 |
2017年 | 171篇 |
2016年 | 196篇 |
2015年 | 185篇 |
2014年 | 251篇 |
2013年 | 234篇 |
2012年 | 326篇 |
2011年 | 265篇 |
2010年 | 236篇 |
2009年 | 225篇 |
2008年 | 172篇 |
2007年 | 217篇 |
2006年 | 149篇 |
2005年 | 135篇 |
2004年 | 107篇 |
2003年 | 107篇 |
2002年 | 65篇 |
2001年 | 81篇 |
2000年 | 73篇 |
1999年 | 54篇 |
1998年 | 63篇 |
1997年 | 61篇 |
1996年 | 49篇 |
1995年 | 53篇 |
1994年 | 34篇 |
1993年 | 37篇 |
1992年 | 19篇 |
1991年 | 30篇 |
1990年 | 27篇 |
1989年 | 30篇 |
1988年 | 17篇 |
1987年 | 15篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 5篇 |
1956年 | 1篇 |
排序方式: 共有4594条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Zifu Yan Oene Dolstra Theo W. Prins Piet Stam Peter B. Visser 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(3):301-308
Powdery mildew (Podosphaera pannosa) is the most important fungal disease in greenhouse roses and is in practice controlled by fungicides. The creation of novel
cultivars with durable resistance to powdery mildew is highly desirable. To understand the inheritance of mildew resistance,
a tetraploid rose population with a size of 181 seedlings was obtained by crossing two tetraploid genotypes each having partial
resistance. The population and its parents were tested under greenhouse conditions with two well-defined monospore isolates
(2 and F1) using artificial inoculation with spore suspensions. Disease score at 11 days post-inoculation, latent period and
rate of symptom development were used to describe seedling resistance. The tests for both isolates exhibited a wide and significant
variation among genotypes for resistance. The distribution of the genotypic means of the disease scores was continuous and
showed a considerable transgression. Statistical analysis, scatter plot of disease scores for the isolates, and correlation
analyses indicated that the two isolates differed in pathogenicity. The outcome of the tests showed that the inoculation assay
with spore suspensions was a reliable and effective way to screen large numbers of genotypes under greenhouse conditions for
genetic and breeding studies. This is the first report on spore-suspension inoculation to be used successfully in rose. 相似文献
95.
针对鞍山海城地区的南果梨和沈阳苏家屯地区的苹果梨初果期和盛果期适宜采收期的生理生化指标进行了详细调查,结果表明:南果梨在海城地区初果期和盛果期最适采收期分别在9月20日、9月15日左右,一级果主要生理指标是:种子变黑指数分别是96.7、95.2,可溶性固形物是16.6%、16.1%,果实自然落果率分别是1.89%、1.26%。苹果梨在苏家屯地区初果期和盛果期最适采收期均在9月30日左右,一级果主要生理指标是:种子变黑指数分别是95.7、96.1,可溶性固形物分别是13.1%、13.4%,果实自然落果率分别是1.98%、2.38%。 相似文献
96.
采用免疫组化链霉素抗生物素蛋白-过氧化物酶法(SP法),检测羔羊期和性成熟期雌性奶山羊下丘脑中催产素表达的变化规律.结果显示,催产素免疫反应阳性神经元在羔羊和性成熟羊的视上核、室旁核、乳头体内侧核等核团均有分布,在羔羊的室周核、视前内侧核等核团广泛分布,但在性成熟羊的这些核团却未见分布.在视上核、室旁核、乳头体内侧核等核团的催产素免疫阳性神经元数量,性成熟羊显著高于羔羊(P<0.01);这些核团中催产素免疫阳性产物的平均灰度值,羔羊显著低于性成熟羊(P<0.01),在其他核团则羔羊高于性成熟羊,且大部分差异明显(P<0.01).结果提示,性成熟羊下丘脑中除室周核、视前内侧核等核团外,室旁核、视上核、乳头体内侧核、乳头体后核等核团,催产素的表达高于羔羊,说明这些核团对生殖系统的发育成熟可能有重要作用. 相似文献
97.
对黄土高原比较有典型代表性的残塬"董志塬"的变暖及冬小麦生态响应特征进行研究,发现"董志塬"近35 a来年平均增温线性趋势达0.0505℃,增温表现出平均气温、最高气温、最低气温同时上升,且冬春季增温速度最快,秋季次之,夏季增温最平缓;增温对冬小麦的生态影响主要体现在全生育期(线性趋势0.91 d/a)、越冬期(线性趋势0.85 d/a)显著缩短,春季发育期普遍提前(返青期以0.57 d/a的线性趋势提前,拔节期以0.42 d/a的线性趋势提前,成熟期以0.48 d/a的线性趋势提前),而春季各发育期间间隔日数并未出现缩短的趋势.认为气候变暖对当地农业生产有利有弊,气候变暖,尤其冬春气温显著升高将导致越冬期土壤水分损耗增大,春旱加剧,不利于春季农业生产;另一方面冬小麦全生育期缩短,成熟期提前,能有效提高复种指数和土地利用率. 相似文献
98.
99.
100.
Results of grid keratotomy, superficial keratectomy and debridement for the management of persistent corneal erosions in 92 dogs 总被引:2,自引:0,他引:2
Ninety-two cases of persistent corneal erosions in dogs were analyzed for breed, gender, age and which eye was affected. The results of the treatment of 92 persistent corneal erosions in dogs by superficial keratectomy (SK), grid keratotomy (GK), or debridement with a sterile dry cotton swab are presented. These techniques gave better rates of healing than have been previously reported. All cases of persistent corneal erosions healed in this study. However, it must be noted that three cases treated with debridement only failed to heal after several treatments and were eventually treated with SK. After one procedure 80 out of 92 (87%) had healed. After one procedure, 63% of cases treated with debridement healed, 100% of cases treated with SK healed, and 85% of cases treated with GK healed. At the first postoperative visit, 88% (21/24 cases) of ulcers treated by SK had healed, and 75% (39/52 cases) of ulcers treated by GK had healed. Only 25% of the persistent corneal erosions had healed at the first visit after debridement. All 24 cases of persistent corneal erosions treated with SK healed after one treatment in a mean +/- SD of 9.3 +/- 3.9 days (median of 7 days). Fifty-two cases were managed with GK; 44 (83%) of these healed with one procedure and eight cases required a second GK procedure to resolve. A mean +/- SD of 13.4 +/- 5.1 days (median of 11.5 days) following GK was required for the persistent corneal erosions to heal. Nineteen cases were initially managed by debridement with a dry cotton swab under local anesthesia. Sixteen out of these 19 debridement cases healed (giving an overall healing rate of 84%) in a mean +/- SD time of 23.4 +/- 11.1 days (median 21.5). There were three cases that did not heal with debridement. These cases were debrided at 10-20 day intervals for 30-60 days, and were then treated with SK. Two of these cases healed within 7 days, the other case required 18 days to heal. Sixty-three per cent of persistent corneal erosions treated with debridement healed after one procedure; however, only four out of 19 cases (21%) were healed at the first revisit. Complications were rare: corneal edema occurred in two cases following multiple GK, and excessive granulation tissue in one case was managed with a SK. There was the occurrence of an ulcer adjacent to the surgery site in four cases, two cases following GK and two cases following SK. 相似文献