全文获取类型
收费全文 | 97311篇 |
免费 | 5015篇 |
国内免费 | 9206篇 |
专业分类
林业 | 9874篇 |
农学 | 12908篇 |
基础科学 | 7194篇 |
14918篇 | |
综合类 | 29200篇 |
农作物 | 5086篇 |
水产渔业 | 3828篇 |
畜牧兽医 | 18357篇 |
园艺 | 3721篇 |
植物保护 | 6446篇 |
出版年
2024年 | 233篇 |
2023年 | 958篇 |
2022年 | 2345篇 |
2021年 | 3332篇 |
2020年 | 2945篇 |
2019年 | 3025篇 |
2018年 | 2322篇 |
2017年 | 3234篇 |
2016年 | 3017篇 |
2015年 | 4131篇 |
2014年 | 4028篇 |
2013年 | 4990篇 |
2012年 | 6003篇 |
2011年 | 6480篇 |
2010年 | 6325篇 |
2009年 | 5799篇 |
2008年 | 5485篇 |
2007年 | 5661篇 |
2006年 | 5236篇 |
2005年 | 4721篇 |
2004年 | 2434篇 |
2003年 | 2383篇 |
2002年 | 2049篇 |
2001年 | 2438篇 |
2000年 | 2453篇 |
1999年 | 2546篇 |
1998年 | 1882篇 |
1997年 | 1701篇 |
1996年 | 1528篇 |
1995年 | 1410篇 |
1994年 | 1234篇 |
1993年 | 1233篇 |
1992年 | 1195篇 |
1991年 | 1078篇 |
1990年 | 912篇 |
1989年 | 761篇 |
1988年 | 653篇 |
1987年 | 547篇 |
1986年 | 370篇 |
1985年 | 257篇 |
1984年 | 214篇 |
1983年 | 187篇 |
1982年 | 142篇 |
1981年 | 130篇 |
1980年 | 111篇 |
1979年 | 152篇 |
1978年 | 95篇 |
1977年 | 75篇 |
1975年 | 82篇 |
1974年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
171.
利用犬温热,细小病毒性肠炎,犬传染性肝炎,狂犬病等弱毒株,以香菇多糖和动物的核糖,多肽做为免疫增强剂,对异源动物羊,猪,犊牛,家兔进行了免疫应答,筛选出了猪做为异源免疫动物。在免疫增强剂的参与下,完成了多次免疫应答,达到了理想的免疫球蛋白(IgG),通过试验摸清了该制剂的免疫程序,确定了生产工艺,经重复性试验,稳定性试验及含量测定,以及临床应用试验和现志应用试验均达以了预期效果,该制剂经冷冻干燥后 相似文献
172.
173.
T Tsuboi Y Kanazawa T Syoji S Tokuhisa 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(6):1179-1181
Bovine follicular oocytes collected from bovine ovaries were exposed to bovid herpesvirus 1 (BHV-1). After washings, these oocytes were cultured to mature. As a result BHV-1 could not be removed from the oocytes and could replicate in the oocytes with cumulus cells, but not in the oocytes without the cells. Moreover, the specific fluorescence for BHV-1 was detected in the cumulus cells by a indirect immunofluorescent technique. Therefore these findings suggested BHV-1 could be absorbed in the oocytes but the replication of BHV-1 was done in the cumulus cells. 相似文献
174.
K Adachi A Yoshimoto T Hasegawa T Shimizu Y Goto S Makimura 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(6):1081-1084
Due to the potential for anti-erythrocyte membrane antibodies as possible enhancers of erythrocyte destruction, the presence of serum anti-erythrocyte membrane antibodies in 31 dogs with Babesia gibsoni infection admitted to a veterinary hospital was investigated by an enzyme linked immunosorbent assay (ELISA) and immunoblotting analyses. This infection resulted in an increase of anti-erythrocyte membrane antibodies in 84% (IgG) and 74% (IgM) of 31 infected dogs, respectively. This was confirmed by the similarity in the protein profiles of the erythrocyte membrane antigens immunoblotted with rabbit antiserum to dog erythrocyte membrane antigens and infected dog serum. These results suggest the production of anti-erythrocyte membrane antibodies was induced by B. gibsoni infection. 相似文献
175.
Dai Huaguo Song Xiaoling Nanjing Agricultural University Li Jianlong Northeast Forestry University 《林业研究》1993,(2)
Through rearing tests and observations under laboratory conditions,biologicalcharacters and mating behavior of Dahurian casebearer(Coleophora dahurica Flkv.)adultswere studied in this paper.Results discovered that the time of emergense of male adultswas 24h to 36h earlier than that of female adults.The peak of sex pheromone secretion ofthe female adults appeared of 24h to 42h after the emergence.The reaction of male adultson the sex pheromone was most sensitive during 30h to 48h after emerged,so the earlieremergence of the male adults was favorable to mating.The phenomenon of repeatedmating did not exist in female adults,but the male adults could mate for several times,with maximum of 4 times.There was a definite behavioral reaction during the matingperiod of male and female adults,and the certain period of feeding and mating times couldaffect the adults longervity to a certain degree. 相似文献
176.
Kano R. Kubota A. Nakamura Y. Watanabe S. Hasegawa A. 《Veterinary research communications》2001,25(8):615-622
Using cDNA from a CRFK cell line as a template, PCR amplification was performed with the Ub1S and poly(dT) primers to isolate feline ubiquitin genes. Sequencing of the 495 bp PCR fragment revealed that the putative amino acids induced by this fragment gave a fusion protein consisting of a ubiquitin polypeptide (76 amino acids) and an extension protein of ribosomal proteins L40 (52 amino acids). The putative amino acid sequence of ubiquitin was identical to those of humans, rats and pigs.The recombinant glutathione S-transferase (GST)–feline ubiquitin fusion proteins were produced in Escherichia coli and purified. The fusion proteins had a molecular weight of about 42 kDa and were detected by immunoblot assay with rabbit anti-ubiquitin antiserum.The mRNAs from heat-shocked and non-heat-shocked cells were subjected to RT-PCR (Ub1S and poly(dT) primers) analysis. The molecular weights of the ubiquitinated proteins in heat-shocked CFRK cells were between 18 kDa and 24 kDa by immunoblot assay.These results suggested that there were more ubiquinated proteins in the heat-shocked CRFK cells than in the pre-heat-shocked cells. 相似文献
177.
王力 《吉林粮食高等专科学校学报》2001,16(3):57-61
xDSL就是一种高速的用户接入技术,这种技术是一种点对点的接入技术,利用现有电话网络的用户线路提供高速数据传输手段,具有广泛的应用范围。介结了xDSL应用范围、种类、各种DSL的特点、技术和实现方法。 相似文献
178.
青岛黄海水产研究所266000 欧盟及国际社会对在动物性食品严禁使用1,2一二苯乙烯类药物。我国也相应制定了严禁在肉食动物中使用己烯雌酚(DES)等激素的法规。继而我国于 1999年制定了《中华人民共和国动物及动物源食品残留监控计划》,加强了对违禁药物的监控力度,规定动物产品中1,2-二苯乙烯类药物的最大残留限量(MRL)为不得检出。目前,检测动物产品中DES残留量的方法较多,有紫外分光光度法、液相色谱法、放射免疫法、GC/MS法等。各方法各有优缺点。本文根据残留监控过程中既要大批量快速测定,又… 相似文献
179.
180.
介绍了农业科技信息生产管理的基本特征,农业科技信息产业结构的变化趋势,在此基础上提出了农业科技信息科学管理的政策与措施。 相似文献