全文获取类型
收费全文 | 30092篇 |
免费 | 1955篇 |
国内免费 | 2980篇 |
专业分类
林业 | 2243篇 |
农学 | 1935篇 |
基础科学 | 1895篇 |
3668篇 | |
综合类 | 14173篇 |
农作物 | 2374篇 |
水产渔业 | 1294篇 |
畜牧兽医 | 4107篇 |
园艺 | 1972篇 |
植物保护 | 1366篇 |
出版年
2024年 | 294篇 |
2023年 | 735篇 |
2022年 | 1561篇 |
2021年 | 1461篇 |
2020年 | 1409篇 |
2019年 | 1362篇 |
2018年 | 888篇 |
2017年 | 1457篇 |
2016年 | 1075篇 |
2015年 | 1483篇 |
2014年 | 1633篇 |
2013年 | 1919篇 |
2012年 | 2407篇 |
2011年 | 2491篇 |
2010年 | 2313篇 |
2009年 | 2077篇 |
2008年 | 2010篇 |
2007年 | 1919篇 |
2006年 | 1665篇 |
2005年 | 1282篇 |
2004年 | 800篇 |
2003年 | 492篇 |
2002年 | 499篇 |
2001年 | 508篇 |
2000年 | 456篇 |
1999年 | 229篇 |
1998年 | 101篇 |
1997年 | 68篇 |
1996年 | 59篇 |
1995年 | 49篇 |
1994年 | 44篇 |
1993年 | 61篇 |
1992年 | 47篇 |
1991年 | 42篇 |
1990年 | 30篇 |
1989年 | 14篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1965年 | 1篇 |
1962年 | 3篇 |
1956年 | 9篇 |
1955年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Transcriptional search to identify and assess reference genes for expression analysis in Solanumlycopersicum under stress and hormone treatment conditions
下载免费PDF全文
![点击此处可从《农业科学学报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
DUAN Yao-ke HAN Rong SU Yan WANG Ai-ying LI Shuang SUN Hao GONG Hai-jun 《农业科学学报》2022,21(11):3216-3229
Tomato(Solanum lycopersicum) is a model plant for research on fruit development and stress response, in which gene expression analysis is frequently conducted. Quantitative PCR(qPCR) is a widely used technique for gene expression analysis, and the selection of reference genes may affect the accuracy of results and even conclusions. Although there have been some frequently used reference genes in tomato, it has been shown that the expressions of some of these genes are not constant in different t... 相似文献
112.
Transcriptome analysis of the spleen of heterophils to lymphocytes ratio-selected chickens revealed their mechanism of differential resistance to Salmonella
下载免费PDF全文
![点击此处可从《农业科学学报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
113.
小球藻作为水体中的初级生产者,是水生生态系统不可或缺的一部分,对促进物质循环、能量流动有着重要意义,同时也是水环境毒理学评价的标准试验藻种。为了给小球藻的水生态风险评估及相应产品的开发提供参考数据,本文系统分析了小球藻培养影响因素,概括了其产生的毒理效应,并对其营养价值与应用前景等进行了综述。本文认为温度、光照、pH、营养盐、氮磷比是小球藻规模化培养过程中的影响因素,重金属、农药、新型纳米材料、抗生素等污染物可对小球藻产生毒性效应,小球藻在污水处理、生物能源等领域具有较好的应用前景。 相似文献
114.
高粱作为中国主要的酿造原料之一,在国民经济发展中占据重要地位。高粱炭疽病是高粱的主要病害之一,在整个生育期中均可发病,且在温暖湿润的热带和亚热带栽种地区更易发生和流行,不仅影响植株的正常生长,严重时会引起产量的大幅下降和籽粒品质的劣变。多年来,高粱病理学家和育种家对高粱炭疽病病原菌菌株分离、病害发生流行规律、发生原因、寄主抗性利用和抗炭疽病基因定位等方面进行了广泛的研究,取得了一些进展。这些研究为炭疽病的生化防控以及培育抗炭疽病品种奠定了基础。开展高粱炭疽病研究,发掘更丰富多样的优异抗性种质资源,减少农药使用,不仅可以满足中国高粱产业对天然有机高粱原料的巨大需求,还可以推动高粱生产向高产优质转变。对高粱炭疽病的分布和发病症状、炭疽病病原菌侵染机理、病害发生流行规律及流行原因、抗性资源鉴定和高粱抗炭疽病基因定位的相关研究进展进行了综合分析和论述,以期从分子水平上更好地认识高粱与炭疽病病原菌之间的相互作用,为高粱炭疽病研究提供参考。 相似文献
115.
LIU Yong-ming OUYANG Jing-ping TU Shu-zhen ZHENG Han-qiao YANG Jing-wei YANG Hai-lu WANG Hai-long 《园艺学报》2000,16(11):1171-1173
AIM and METHODS: The protective effects of multi-enzyme Ⅱ was studied on cultured endothelial cells which was injuried by hyperlipidemia serum. RESULTS: Hyperlipidemia serum increased ICAM-1 expression on the surface of endothelial cells, and decreased NO2- release significantly (P<0.01). ICAM-1 expression could be reduced and NO2- release could be enhanced markedly by multi-enzyme Ⅱ (P<0.01). CONCLUSION: Multi-enzyme Ⅱ had an obvious protective effect on vascular endothelial cells which was injuried by hyperlipidemia seurm. Multi-enzyme Ⅱ could clean out oxide free radicals effectively because it had the acitive structure of both SOD and CAT. 相似文献
116.
OUYANG Jing-ping LIU Yong-ming ZHENG Han-qiao WEI Lei TU Shu-zhen YANG Hai-lu CUI Ye-jian 《园艺学报》2000,16(1):70-73
AIM: The effects of BDM on isolated rat heart in cold cardioplegia were studied. METHODS: Rat heart were subjected to cold cardioplegia at 4℃ for 8, 18 and 24 h.Then each heart was perfused (90 cm H2O) in Langendorff model at 37℃ for 40 min. In the high K+ group(n=24) the hearts were preserved in St.Thomas cardioplegic solution, in BDM group(n=24) hearts were preserved in K-H solution with BDM 30 mmoL/L. RESULTS: After 18 h, heart rate and the coronary flow in BDM group were significantly higher than in high K+ group(P<0.05). Activity of Na+-K+-ATPase in cell membrane and in mitochondrial membrane in the BDM group was significantly higher than high K+ group(P<0.01). After 24 h, all hearts in high K+ group were dead, but were alive in BDM group. CONCLUSION: Under given experiment conditions, BDM did enhance the tolerance to cold ischemia significantly. The results showed that BDM may become a useful agent for prolong the storage period of heart in cold cardioglegia. 相似文献
117.
HUANG Xiu-rong QI Ming-xin SHEN Shi-ren ZHENG Liang-pu LIN Jiu-mao WEI Ning 《园艺学报》2000,16(3):258-261
AIM: To investigate the effect of nitric oxide (NO) in ocular inflammation after intraocular lens implantation. METHODS: All New Zealand rabbits were divided randomly into three groups: 1. control group, 2. L-arginine (L-Arg) group, 3. N-nitro-L-arginine (L-NNA) group. Extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens implantation (IOL) were operated in all animals of each groups. The inflammatory response of all rabbit eyes, including cornea edema and anterior chamber exudation were investigated 1, 3, 7, 14, 30 days afteroperation. Meanwhile, aqueous humor was drawn for white blood cell (WBC) counting and classifying, as well as for NO2-/NO3- measurement. RESULTS:NO2-/NO3- contents, total WBC and anterior chamber exudation in aqueous humor of L-Arg group were higher than that in control group. While that of L-NNA group were lower than that in control group.CONCLUSION:NO plays a role in intraocular inflammatory response after intraocular lens implantation. L-NNA, a nitric oxide synthase exhibitor, decreased NO contents, therefore it may reduce intraocular inflammatory response after intraocular lens implantation. 相似文献
118.
AIM: To evaluate the association between apolipoprotein E(apoE) gene polymorphism and sporadic Alzheimer's disease (AD). METHOD: A case-control study was undertaken detecting the polymorphism of apoE by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).RESULTS:(1)The frequencies of 3/4 genotype and 4 al ele in AD were significant ly higher than that in age-matched controls(P<0.05).(2)The frequency of G/G genotype for apoE IE1 in AD was significantly higher than that in age-mat ched control(P<0.05).(3)The apoE 4 al ele was associated with a tripling of the risk for AD compared with no 4 allele(odd ratio 2.932, 95%CI 1.379~6.226);Homozygosity of the G allele in IE1 was associated with adoubling of the risk for AD compared with the G/C and C/C genotypes(odd rat io 2.223, 95%CI 1.075~4.599).However, the IE1 G al ele is also closely associated with apoE 4.When the sample was split on the basis of apo Egenotype, the associat ion between IE1 G/G genotype and AD was no longer statistically significant.CONCLUSION: ApoE ε4 was a risk factor of AD, and the apparent association between IE1 G/G and AD is a consequence of the association between the ε4 and IE1 G/G genotype. 相似文献
119.
CHEN Yu-lu WANG Xin-yu ZHENG Shu-zhan DU Yan-fei YE Qiang LI Jia-fu FAN Zhong-cai LI Guang 《园艺学报》2000,36(8):1531-1536
AIM To observe the effect of recombinant mouse interleukin-11 (rmIL-11)injected subcutaneously into mice on heart structure and function and to determine its pro-fibrotic effect. METHODS C57BL/6 mice were randomly divided into experimental group and control group.The mice in experimental group were injected subcutaneously with recombinant mouse IL-11 at the dose of 100 μg·kg-1·d-1 for 3 consecutive weeks, while the control group were given equal volume of normal saline in the same way. After the experiment was finished, the parameters of heart function were measured by echocardiography.The heart weight was weighed and the cardiac weight index (CWI) was calculated. HE staining and Masson's trichrome staining were performed to observe the pathological changes and the extent of myocardial fibrosis in mouse myocardia respectively, and the cardiac collagen volume fraction (CVF) was calculated. The expression levels of extracellular matrix proteins in the myocardial tissues of mice, including type Ⅰ collagen, type Ⅲ collagen and fibronectin, were determined by Western blot. RESULTS Left ventricular ejection fraction and left ventricular fraction shortening in experimental group were obviously lower than those in control group (P <0.01), however left ventricular end-diastolic diamension and left ventricular end systolic dimension were significantly higher than those in control group (P <0.05).Compared with control group, the CWI was increased (P <0.01), the myocardial arrangement was disorder, the necrosis of cardiac myocytes was increased, and excessive deposition of collagen was observed in the myocardial tissues in experimental group. Correspondingly, the CVF and protein levels of type Ⅰ collagen, type Ⅲ collagen and fibronectin in the left ventricle in experimental group were increased significantly (P <0.05). CONCLUSION Injection of rmIL-11 into the mice subcutaneously induces fibrogenesis in the heart, which implies that IL-11 is likely a novel pro-fibrotic factor. 相似文献
120.
用灭活的〔Flammulinasubnudus (Pr .)Sing〕双核菌株原生质体与〔Flammulinavelutipes (Fr.)Sing〕双核菌株原生质体融合 ,在 2 2℃的条件下筛选得融合子。融合频率为 0× 10 -5~ 4 1× 10 -5。融合子与双亲有明显的拮抗性。融合子的菌丝体形态 ,氨基酸含量 ,子实体的形态 ,以及酸性磷酸酶的测定都与双亲不同。 相似文献