全文获取类型
收费全文 | 286篇 |
免费 | 14篇 |
国内免费 | 23篇 |
专业分类
林业 | 57篇 |
农学 | 69篇 |
基础科学 | 4篇 |
7篇 | |
综合类 | 79篇 |
农作物 | 10篇 |
水产渔业 | 3篇 |
畜牧兽医 | 52篇 |
园艺 | 38篇 |
植物保护 | 4篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 12篇 |
2020年 | 15篇 |
2019年 | 10篇 |
2018年 | 12篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 10篇 |
2012年 | 23篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 16篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有323条查询结果,搜索用时 15 毫秒
31.
花生野生种Arachiscardenasii与栽培品种以常规方法杂交,其杂交成功率和杂种生活力均较低。利用胚营救技术将杂交获得的未成熟胚珠和胚进行离体培养,可诱导幼胚分化发育或使胚成熟萌发。离体培养杂种小苗的带腋芽茎段,用MS+BA4ms/L+CH600mg/L培养基诱导产生了愈伤组织和芽原基。通过继代增殖培养,平均每个愈伤组织获得22.6和24.6个芽原基以及6.1和7.2个无根小苗。经诱根培养(MS+NAA0.2mg/L),再生苗即生长成为完整植株。 相似文献
33.
以木纳格葡萄败育型胚珠为材料进行胚挽救,按照已建立的适合白木纳格葡萄败育型胚珠培养体系进行实验,获得了大量木纳格葡萄胚挽救幼苗,炼苗后移栽到大田中种植。并结合已有分子标记技术,对胚挽救幼苗进行鉴定,结果显示45株胚挽救幼苗中,有21株扩增获得了目的片段,初步确定为具有无核性状的葡萄苗。 相似文献
34.
35.
【目的】为了培育抗病抗寒无核葡萄新品种,【方法】以2个种子败育型无核品种‘波尔莱特’、‘红无籽露’作母本,以抗病抗寒的中国野生山葡萄株系‘黑龙江实生’、‘双优’及欧山杂种‘北醇’、‘00-1-10’(‘玫瑰香’ב黑龙江实生’)分别作父本杂交,授粉51 d后将胚珠分别接种于ER和MM4培养基上进行胚挽救,培养60 d后在WPM+BA 0.2 mg.L-1培养基上诱导成苗。【结果】结果表明,2个母本品种胚挽救的适宜培养基不同,‘波尔莱特’作母本适合于ER培养基,‘红无籽露’作母本适合于MM4培养基。2个母本基因型对胚珠的发育率和成苗率的影响差异不大,‘波尔莱特’略优于‘红无籽露’;但4个父本基因型对胚挽救效果影响较大,以欧山杂种‘00-1-10’和‘北醇’作父本的杂交组合胚株的发育率和成苗率明显高于山葡萄‘黑龙江实生’、‘双优’作父本的杂交组合。共获得无核葡萄胚挽救新种质50个株系。【结论】在胚挽救过程中,不同基因型的无核葡萄适宜于不同的基本培养基,欧山杂种比山葡萄更适宜于作杂交的父本。 相似文献
36.
Katherine Smallwood Jean‐Benoit Tanis Iain A. Grant Laura Blackwood David R. Killick Isabel Amores‐Fuster James Elliott Aran Mas Aaron Harper Mary Marrington Riccardo Finotello 《Veterinary and comparative oncology》2019,17(2):165-173
The DMAC protocol (dexamethasone, melphalan, actinomycin‐D, cytarabine) has been evaluated in American studies for the treatment of relapsed canine lymphoma, comparing similarly to other rescue protocols. The aim of this study was to evaluate efficacy and toxicity of DMAC, in a larger UK cohort of resistant canine lymphomas. Medical records of dogs with resistant non‐Hodgkin high‐grade lymphomas that received DMAC as a rescue protocol were reviewed from 2007 to 2017. Response, time from initiation to discontinuation (TTD) and toxicity (Veterinary Cooperative Oncology Group criteria) were assessed. One hundred dogs were included; 86 received CEOP (modified CHOP including epirubicin) as first‐line treatment. Thirty‐five dogs (35%) responded: 21 complete responders (CRs) and 14 partial responders (PRs). Responders had significantly longer TTD (P < 0.001) compared with non‐responders: 62 days (range 28‐952) for CR vs 32 days (range 20‐70) for PR. Six CR received more than six cycles of DMAC (range 7‐36 cycles) and experienced a longer TTD (median 508, range 126‐952 days). Thrombocytopenia occurred in 45% (24 grade 1‐2, 21 grade 3‐4) and neutropenia in 36% of cases (29 grade 1‐2, 7 grade 3‐4). Gastrointestinal toxicity occurred in 42% of dogs (40 grade 1‐2, 2 grade 3‐4). Owing to chemotherapy toxicity, treatment was discontinued in five, and hospitalization required in six cases. In this study, response to DMAC was lower and of generally shorter duration than previously reported. Toxicity was high, but infrequently led to hospitalization or discontinuation of treatment. 相似文献
37.
Evaluation of a multi‐agent chemotherapy protocol combining lomustine,procarbazine and prednisolone (LPP) for the treatment of relapsed canine non‐Hodgkin high‐grade lymphomas 下载免费PDF全文
J.‐B. Tanis S. L. Mason T. W. Maddox L. Blackwood D. R. Killick I. Amores‐Fuster A. Harper R. Finotello 《Veterinary and comparative oncology》2018,16(3):361-369
The standard of care treatment for canine lymphoma is multi‐agent chemotherapy containing prednisolone, cyclophosphamide, vincristine and an anthracycline such as doxorubicin (CHOP) or epirubicin (CEOP). Lomustine, vincristine, procarbazine, and prednisone (LOPP) has been evaluated as a rescue, with encouraging results; however, resistance to vincristine is likely in patients relapsing on CHOP/CEOP, and this agent may enhance LOPP toxicity without improving efficacy. The aim of this study was to evaluate responses to a modified‐LOPP protocol that does not include vincristine (LPP) and is administered on a 21‐day cycle. Medical records of dogs with high‐grade multicentric lymphoma from 2012 to 2017 were reviewed. Dogs with relapsed lymphoma that received LPP as a rescue protocol were enrolled. Response, time from initiation to discontinuation (TTD) and toxicity of LPP were assessed. Forty‐one dogs were included. Twenty‐five dogs (61%) responded to LPP including 12 complete responses (CR) and 13 partial responses (PR). Responders had a significantly longer TTD (P < .001) compared to non‐responders with 84 days for CR and 58 days for PR. Neutropenia was documented in 20 dogs (57%): 12 grade I to II, 8 grade III to IV. Thrombocytopenia was infrequent (20%): 5 grade I to II, 2 grade III to IV. Twelve dogs developed gastrointestinal toxicity (30%): 10 grade I to II and 2 grade III. Nineteen dogs had elevated ALT (59%): 9 grade I to II, 10 grade III to IV. Treatment was discontinued due to toxicity in 8 dogs (19%). The LPP protocol shows acceptable efficacy and toxicity‐profile and minimizes in‐hospital procedures. 相似文献
38.
Interspecific crosses were made between the cultivated sunflower inbred line HA89 and accessions of five wild perennial Helianthus
species (H. giganteus L., H. laevigatus T. & G., H. resinosus Small, H. pauciflorus Nutt. and H. decapetalus L.) resistant
to broomrape ( Orobanche cernua Loefl.). Using the genetic male-sterile isogenic version of that line as female, successful
reciprocal crosses were also obtained with all these wild species except with H. decapetalus. Five-day-old hybrid embryos
were excised and cultured in vitro. In all cases, few mature plants were obtained from embryos in early developmental stages
(early heart and globular) but up to 28% mature plants were obtained from embryos in later stages of development. Very immature
embryos were difficult to excise without damage. Hybrid embryos and mature plants were obtained from all five wild species.
Interspecific hybrid embryos from different wild species showed distinct developmental potentials, the proportion of hybrid
embryos in different developmental stages varying among species. Differences in the proportion of hybrid embryos at the several
developmental stages were also obtained for the reciprocal crosses (cultivated × wild), which showed higher proportion of
fully developed embryos. Hybrids involving H. giganteus and cultivated sunflower were difficult to obtain without the use
of embryo culture. Embryo culture proved to be an useful tool to overcome post-zygotic hybrid incompatibility in different
Helianthus spp., and facilitated interspecific transfer of resistance to O. cernua.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
39.
The efficiency of two embryo rescue techniques, direct ovule culture and ovary-slice culture followed by ovule culture, is
studied in crosses with Tulipa gesneriana as maternal genotype. The germination percentages increased, in most cases, significantly with increasing ages of te ovary-slices
and ovules at the start of the cultures. The low number of embryos recovered at early culture dates is caused by a higher
rate of embryo abortion and by retarded embryo development. The germination percentages for ovary-slice culture followed by
ovule culture was mostly comparable to direct ovule culture. Unique hybrids have been obtained from the crosses T. gesneriana × T. agenensis and T. gesneriana × T. praestans.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
40.
多花黑麦草和四倍体苇状羊茅属间杂种F#-1及其双倍体的细胞遗传学研究 总被引:1,自引:0,他引:1
本研究获得了多花黑麦草(Lolium multiflorum Lam 2n=2x=14)和四倍体苇状羊茅(Festuca arundinacea var.glaucescens Boiss 2n=4x=28)的属间杂种。Lmx Fa.g杂种在形态上呈中间型,而反交杂种则倾向于母本。杂种的细胞学研究表明:多花黑麦草的染色体组(A)与四倍体苇状羊茅的两组染色体(B和B′)亲和性差;相对来说,羊茅属的细胞质有利于A、B、B′三组染色体的配对。杂种F#-1花药不开裂,花粉畸形败育。合成的双倍体细胞学上不稳定,花粉KI-I#-2可染率极低。本文还讨论了利用杂种的途径和实践意义。 相似文献