全文获取类型
收费全文 | 692篇 |
免费 | 59篇 |
专业分类
林业 | 24篇 |
农学 | 2篇 |
基础科学 | 2篇 |
69篇 | |
综合类 | 69篇 |
农作物 | 21篇 |
水产渔业 | 25篇 |
畜牧兽医 | 475篇 |
园艺 | 15篇 |
植物保护 | 49篇 |
出版年
2023年 | 8篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 20篇 |
2019年 | 27篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 15篇 |
2013年 | 29篇 |
2012年 | 36篇 |
2011年 | 45篇 |
2010年 | 17篇 |
2009年 | 20篇 |
2008年 | 32篇 |
2007年 | 30篇 |
2006年 | 29篇 |
2005年 | 39篇 |
2004年 | 52篇 |
2003年 | 41篇 |
2002年 | 41篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1987年 | 14篇 |
1986年 | 11篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 6篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1923年 | 2篇 |
1922年 | 2篇 |
1918年 | 2篇 |
1914年 | 1篇 |
排序方式: 共有751条查询结果,搜索用时 15 毫秒
731.
732.
733.
734.
735.
Nene V Wortman JR Lawson D Haas B Kodira C Tu ZJ Loftus B Xi Z Megy K Grabherr M Ren Q Zdobnov EM Lobo NF Campbell KS Brown SE Bonaldo MF Zhu J Sinkins SP Hogenkamp DG Amedeo P Arensburger P Atkinson PW Bidwell S Biedler J Birney E Bruggner RV Costas J Coy MR Crabtree J Crawford M Debruyn B Decaprio D Eiglmeier K Eisenstadt E El-Dorry H Gelbart WM Gomes SL Hammond M Hannick LI Hogan JR Holmes MH Jaffe D Johnston JS Kennedy RC Koo H Kravitz S Kriventseva EV Kulp D Labutti K Lee E Li S Lovin DD 《Science (New York, N.Y.)》2007,316(5832):1718-1723
We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species. 相似文献
736.
Holmes KV 《Science (New York, N.Y.)》2005,309(5742):1822-1823
737.
738.
739.
Gregory D Roach Kathryn J Reid Sally Ferguson Drew Dawson 《Journal of circadian rhythms》2006,4(1):8-5
Background
The aim of the study was to examine the role that melatonin production plays in the regulation of sleep consolidation in a population of shiftworkers working and sleeping in their natural environments. 相似文献740.
Sidhu PK Landoni MF Aliabadi MH Toutain PL Lees P 《Journal of veterinary pharmacology and therapeutics》2011,34(4):376-387
In a four-period, cross-over study, the fluoroquinolone antibacterial drug marbofloxacin (MB) was administered to calves, alone and in combination with the nonsteroidal anti-inflammatory drug tolfenamic acid (TA). Both drugs were administered intramuscularly (IM) at doses of 2 mg/kg. A tissue cage model of inflammation, based on the actions of the mild irritant carrageenan, was used to evaluate the pharmacokinetics (PK) of MB and MB in combination with TA. MB mean values of area under concentration-time curve (AUC) were 15.1 μg·h/mL for serum, 12.1 μg·h/mL for inflamed tissue cage fluid (exudate) and 9.6 μg·h/mL for noninflamed tissue cage fluid (transudate). Values of C(max) were 1.84, 0.35 and 0.31 μg/mL, respectively, for serum, exudate and transudate. Mean residence time (MRT) of 23.6 h (exudate) and 22.6 h (transudate) also differed significantly from serum MRT (8.6 h). Co-administration of TA did not affect the PK profile of MB. The pharmacodynamics of MB was investigated using a bovine strain of Mannheimia haemolytica. Time-kill curves were established ex vivo on serum, exudate and transudate samples. Modelling the ex vivo serum time-kill data to the sigmoid E(max) equation provided AUC(24 h) /MIC values required for bacteriostatic (18.3 h) and bactericidal actions (92 h) of MB and for virtual eradication of the organism was 139 h. Corresponding values for MB + TA were 20.1, 69 and 106 h. These data were used to predict once daily dosage schedules for a bactericidal action, assuming a MIC(90) value of 0.24 μg/mL, a dose of 2.6 mg/kg for MB and 2.19 mg/kg for MB + TA were determined, which are similar to the currently recommended dose of 2.0 mg/kg. 相似文献