全文获取类型
收费全文 | 251篇 |
免费 | 13篇 |
国内免费 | 3篇 |
专业分类
林业 | 19篇 |
农学 | 2篇 |
59篇 | |
综合类 | 50篇 |
农作物 | 11篇 |
水产渔业 | 24篇 |
畜牧兽医 | 40篇 |
园艺 | 1篇 |
植物保护 | 61篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 11篇 |
2012年 | 11篇 |
2011年 | 25篇 |
2010年 | 7篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 14篇 |
2005年 | 12篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 5篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1964年 | 5篇 |
1963年 | 2篇 |
排序方式: 共有267条查询结果,搜索用时 31 毫秒
81.
Human endothelial cell growth factor: cloning, nucleotide sequence, and chromosome localization 总被引:78,自引:0,他引:78
M Jaye R Howk W Burgess G A Ricca I M Chiu M W Ravera S J O'Brien W S Modi T Maciag W N Drohan 《Science (New York, N.Y.)》1986,233(4763):541-545
Several of the endothelial cell polypeptide mitogens that have been described probably play a role in blood vessel homeostasis. Two overlapping complementary DNA clones encoding human endothelial cell growth factor (ECGF) were isolated from a human brain stem complementary DNA library. Southern blot analysis suggested that there is a single copy of the ECGF gene and that it maps to human chromosome 5 at bands 5q31.3 to 33.2 A 4.8-kilobase messenger RNA was present in human brain stem messenger RNA. The complete amino acid sequence of human ECGF was deduced from the nucleic acid sequence of these clones; it encompasses all the well-characterized acidic endothelial cell polypeptide mitogens described by several laboratories. The ECGF-encoding open reading frame is flanked by translation stop codons and provides no signal peptide or internal hydrophobic domain for the secretion of ECGF. This property is shared by human interleukin-1, which is approximately 30 percent homologous to ECGF. 相似文献
82.
Pang PC Chiu PC Lee CL Chang LY Panico M Morris HR Haslam SM Khoo KH Clark GF Yeung WS Dell A 《Science (New York, N.Y.)》2011,333(6050):1761-1764
Human fertilization begins when spermatozoa bind to the extracellular matrix coating of the oocyte, known as the zona pellucida (ZP). One spermatozoan then penetrates this matrix and fuses with the egg cell, generating a zygote. Although carbohydrate sequences on the ZP have been implicated in sperm binding, the nature of the ligand was unknown. Here, ultrasensitive mass spectrometric analyses revealed that the sialyl-Lewis(x) sequence [NeuAcα2-3Galβ1-4(Fucα1-3)GlcNAc], a well-known selectin ligand, is the most abundant terminal sequence on the N- and O-glycans of human ZP. Sperm-ZP binding was largely inhibited by glycoconjugates terminated with sialyl-Lewis(x) sequences or by antibodies directed against this sequence. Thus, the sialyl-Lewis(x) sequence represents the major carbohydrate ligand for human sperm-egg binding. 相似文献
83.
K Muegge T M Williams J Kant M Karin R Chiu A Schmidt U Siebenlist H A Young S K Durum 《Science (New York, N.Y.)》1989,246(4927):249-251
84.
Neuroleptic drug-induced dopamine receptor supersensitivity: antagonism by L-prolyl-L-leucyl-glycinamide 总被引:1,自引:0,他引:1
An animal model of tardive dyskinesia was used to evaluate the potential antidyskinetic properties of the neuropeptide L-prolyl-L-leucyl-glycinamide (PLG). In rats, PLG administered concurrently with the neuroleptic drug haloperidol or chlorpromazine antagonized the enhancement of specific [3H]spiroperidol binding in the striatum that is associated with long-term neuroleptic treatment. The results are discussed in relation to a possible functional coupling of the putative PLG receptor with neuroleptic-dopamine receptor complex and clinical implications for tardive dyskinesia. 相似文献
85.
Loftus BJ Fung E Roncaglia P Rowley D Amedeo P Bruno D Vamathevan J Miranda M Anderson IJ Fraser JA Allen JE Bosdet IE Brent MR Chiu R Doering TL Donlin MJ D'Souza CA Fox DS Grinberg V Fu J Fukushima M Haas BJ Huang JC Janbon G Jones SJ Koo HL Krzywinski MI Kwon-Chung JK Lengeler KB Maiti R Marra MA Marra RE Mathewson CA Mitchell TG Pertea M Riggs FR Salzberg SL Schein JE Shvartsbeyn A Shin H Shumway M Specht CA Suh BB Tenney A Utterback TR Wickes BL Wortman JR Wye NH Kronstad JW Lodge JK 《Science (New York, N.Y.)》2005,307(5713):1321-1324
86.
精油防治仓库害虫的实仓应用 总被引:5,自引:0,他引:5
采用4种精油对4种仓库害虫进行了模拟实仓防治试验.结果发现,0.2%(W/W)肉桂油拌种对小麦的保护效果可维持8个月以上.以0.45mg/cm~2的剂量处理麻袋,齿叶黄皮和八角茴香精油处理能保持小麦4个月无虫,肉桂油可保持8个月无虫.实仓试验中发现,15ppm马拉硫磷加15ppm肉桂油混用处理.虫口减退率达100%.30ppm马拉硫磷和30ppm肉桂油处理的虫口减退率分别为89.8%和98.5%. 相似文献
87.
88.
Opposite patterns of branchial Na+/K+-ATPase (NKA) responses were found in euryhaline milkfish (Chanos chanos) and pufferfish (Tetraodon nigroviridis) upon salinity challenge. Because the electrochemical gradient established by NKA is thought to be the driving force for
transcellular Cl− transport in fish gills, the aim of this study was to explore whether the differential patterns of NKA responses found in
milkfish and pufferfish would lead to distinct distribution of Cl− transporters in their gill epithelial cells indicating different Cl− transport mechanisms. In this study, immunolocalization of various Cl− transport proteins, including Na+/K+/2Cl− cotransporter (NKCC), cystic fibrosis transmembrane conductance regulator (CFTR), anion exchanger 1 (AE1), and chloride channel
3 (ClC-3), were double stained with NKA, the basolateral marker of branchial mitochondrion-rich cells (MRCs), to reveal the
localization of these transporter proteins in gill MRC of FW- or SW-acclimated milkfish and pufferfish. Confocal microscopic
observations showed that the localization of these transport proteins in the gill MRCs of the two studied species were similar.
However, the number of gill NKA-immunoreactive (IR) cells in milkfish and pufferfish exhibited to vary with environmental
salinities. An increase in the number of NKA-IR cells should lead to the elevation of NKA activity in FW milkfish and SW pufferfish.
Taken together, the opposite branchial NKA responses observed in milkfish and pufferfish upon salinity challenge could be
attributed to alterations in the number of NKA-IR cells. Furthermore, the localization of these Cl− transporters in gill MRCs of the two studied species was identical. It depicted the two studied euryhaline species possess
the similar Cl− transport mechanisms in gills. 相似文献
89.
Schisandrin B (Sch B) and schisandrin C (Sch C), but not schisandrin A and dimethyl diphenyl bicarboxylate, protected rat skin tissue against solar irradiation-induced oxidative injury, as evidenced by a reversal of solar irradiation-induced changes in cellular reduced glutathione and α-tocopherol levels, as well as antioxidant enzyme activities and malondialdehyde production. The cytochrome P-450-mediated metabolism of Sch B or Sch C caused ROS production in rat skin microsomes. Taken together, Sch B or Sch C, by virtue of its pro-oxidant action and the subsequent eliciting of a glutathione antioxidant response, may prevent photo-aging of skin. 相似文献
90.
In most sciaenids, males possess sonic muscles and produce sound through the contraction of these muscles and amplification
of the swim bladder. The sonic muscles in some fishes exhibit seasonal changes in size. For example, they are hypertrophic
in the spawning season, and atrophic in the non-spawning months. The protein profiles of the sonic muscle, red muscle, and
white muscle in the Johnius macrorhynus were shown by two-dimensional electrophoresis (2-DE) and were compared to reveal differential protein expressions. About
80 up-regulated protein spots in the sonic muscle, and 30 spots related to six contractile proteins (fast muscle myosin heavy
chain, skeletal alpha actin, alpha actin cardiac, tropomyosin, myosin light chain 2, and myosin light chain 3), four energy
metabolic enzymes (enolase, acyl-CoA synthetase, creatine kinase, and cytochrome P450 monooxygenase), and two miscellaneous
proteins (DEAD box protein and cyclin H) were identified. Seasonal hypertrophy and atrophy of the sonic muscles related to
the reproductive cycle were verified in male big-snout croaker. The contents of some proteins were significantly different
in the muscles under these conditions. The levels of cytochrome P450 monooxygenase, fast muscle myosin heavy chain, DEAD box
proteins, isocitrate dehydrogenase, and creatine kinase were up-regulated in the hypertrophic muscle, but the levels of alpha
actin cardiac, myosin light 2, and myosin light 3 were lower than in the atrophic muscle. Potential reasons for these differences
in protein expression related to physiological adaptation are discussed. 相似文献