全文获取类型
收费全文 | 13771篇 |
免费 | 955篇 |
国内免费 | 1350篇 |
专业分类
林业 | 1006篇 |
农学 | 766篇 |
基础科学 | 601篇 |
1516篇 | |
综合类 | 7051篇 |
农作物 | 908篇 |
水产渔业 | 525篇 |
畜牧兽医 | 1959篇 |
园艺 | 1027篇 |
植物保护 | 717篇 |
出版年
2024年 | 134篇 |
2023年 | 321篇 |
2022年 | 679篇 |
2021年 | 727篇 |
2020年 | 600篇 |
2019年 | 559篇 |
2018年 | 473篇 |
2017年 | 741篇 |
2016年 | 426篇 |
2015年 | 641篇 |
2014年 | 717篇 |
2013年 | 865篇 |
2012年 | 1245篇 |
2011年 | 1183篇 |
2010年 | 1166篇 |
2009年 | 1004篇 |
2008年 | 979篇 |
2007年 | 875篇 |
2006年 | 737篇 |
2005年 | 608篇 |
2004年 | 393篇 |
2003年 | 229篇 |
2002年 | 209篇 |
2001年 | 229篇 |
2000年 | 179篇 |
1999年 | 65篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 16篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1962年 | 2篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1956年 | 11篇 |
1955年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
AIM:To investigate the inhibitory effects of resveratrol on chondrosarcoma and the relation with mitochondrial and PI3K/Akt pathways. METHODS:Chondrosarcoma SW1353 cells were treated with resveratrol at concentrations of 25, 50 and 100 μmol/L for the time intervals of 24 h, 48 h and 72 h. The viability and apoptosis of the SW1353 cells in the presence or absence of resveratrol were analyzed by CCK8 assay and Hoechst 33258 staining, respectively. The protein levels of Bcl-2, Bax, activated caspase-3, Akt and p-Akt were detected by Western blotting. The cell migration ability was determined by wound scratch assay. RESULTS:Exposure of the cells to resveratrol resulted in a decrease in the cell viability in a dose- and time-dependent manner (P<0.05). visible nuclei with apoptotic characteristics in resveratrol group were observed. The protein levels of activated caspase-3 and Bax were increased, and Bcl-2 and p-Akt were decreased compared with control group. The total Akt were not significantly changed. Resveratrol also significantly reduced the migration of tumor cells. CONCLUSION:Resveratrol induces apoptosis of chondrosarcoma, which plays a role of part through mitochondrial and PI3K/Akt signaling pathways. 相似文献
972.
AIM:To study the effect of small interfering RNA (siRNA) on the expression of beta 2-microglo-bulin (β2M) in pre-differentiated bone marrow mesenchymal stem cells (BMSCs). METHODS:The β2M siRNA was transfected into the pre-differentiated BMSCs with Lipofectamine 2000. BMSCs were divided into transfection group, blank control group and negative control group. The expression of β2M at mRNA and protein levels was determined by real-time qPCR, Western blotting and laser confocal microscopy. The productions of aggrecan and type II collagen in pre-differentiated BMSCs were determined by toluidine blue staining and type Ⅱ collagen immunofluorescence. RESULTS:The results of real-time qPCR, Western blotting and laser confocal microscopy showed that siRNA successfully inhibited the expression of β2M at mRNA and protein levels in the pre-differentiated BMSCs. The results of toluidine blue and type Ⅱ collagen immunofluorescence staining showed that siRNA does not affect the productions of aggrecan and type Ⅱ collagen in the pre-differentiated BMSCs. CONCLUSION:siRNA targeting β2M reduces the expression of β2M in the pre-differentiated BMSCs and does not affect the chondrocyte characteristics of pre-differentiated BMSCs. 相似文献
973.
AIM:To investigate the effect of c-Myc inhibitor 10058-F4 on human chronic myeloid leukemia (CML) K562 cells and imatinib-resistant K562/G cells. METHODS:The protein expression of c-Myc was detected by Western blotting. Cell proliferation was evaluated by MTT assay and colony formation assay. PI staining was used to determine the cell cycle distribution. Annexin V-PI staining was applied for apoptosis detection. RESULTS:Imatinib-resistant K562/G cells displayed lower sensitivity to imatinib than K562 cells with high expression of c-Myc. Treatment with specific c-Myc inhibitor 10058-F4 inhibited the cell proliferation in a dose- and time-dependent manner, and K562/G displayed more sensitivity to 10058-F4 than K562 cells. 10058-F4 also induced cell cycle arrest in G0/G1 phase and induced apoptotic cell death in the 2 cells. Importantly, 10058-F4 suppressed the colony formation ability in K562 and K562/G cells. CONCLUSION:c-Myc is a novel target to overcome imatinib-induced drug resistance, and c-Myc inhibitor provides a new approach in CML therapy. 相似文献
974.
975.
‘兴桂3号’是以‘TZS-e’为母本、‘LPCS-a’为父本育成的早熟优质有籽西瓜新品种。该品种全生育期春季栽培80-87 d,秋季栽培60-66 d,果实发育期25-28 d。果实短椭圆形,果皮青绿色覆深绿色清晰宽条带。果皮厚度0.7-1.0 cm,不易裂瓜,抗压及耐贮运性好。瓜瓤鲜红色,瓤质细嫩、实脆,清甜爽口,中心可溶性固形物含量11.5%以上。单果质量2.0-3.5 kg,露地栽培每667 m2产量2 000-2 500 kg,大棚栽培每667 m^2产量2 500-3 200 kg。大棚和露地均适宜栽培。2013年6月通过广西农作物品种审定委员会审定,审定编号:桂审瓜2013017号。 相似文献
976.
977.
978.
试验旨在探讨低蛋白日粮对育肥猪养分消化率和排泄量的影响。选用42头初始体重为(91.13±1.64)kg的杜长大育肥猪分为2组,每组3个重复,分别饲喂粗蛋白水平为15.49%(对照组)和12.59%(低蛋白组)的日粮。试验期30d。结果表明:(1)低蛋白组干物质、粗脂肪消化率显著提高(P0.01),粗蛋白、钙、磷消化率无显著变化;(2)低蛋白组精氨酸、天冬氨酸、异亮氨酸消化率比对照组分别低2.02%(P0.05)、5.42%(P0.05)、2.97%(P0.05),苏氨酸、蛋氨酸、脯氨酸消化率较对照组分别提高2.93%(P0.05)、1.43%(P0.05)、1.19%(P0.05);(3)低蛋白组育肥猪每天的氮排泄量比对照组低23.96%(P0.05),而有机物、磷、钙排泄量无显著差异(P0.05)。试验结果显示,日粮蛋白水平降低2.9个百分点可以改善养分的消化率,减少氮排放,但降低了精氨酸的消化率。 相似文献
979.
本试验旨在研制鸭疫里默氏杆菌GroEL蛋白的单克隆抗体。将鸭疫里默氏杆菌WJ4菌株的groEL基因进行原核表达,重组蛋白经过纯化后作为免疫原免疫BALB/c小鼠。经过3次免疫后,取免疫小鼠脾细胞与SP2/0骨髓瘤细胞进行细胞融合,用间接ELISA筛选阳性细胞株并进行3次亚克隆后制备小鼠腹水单克隆抗体。共获得2株稳定分泌鸭疫里默氏杆菌GroEL单克隆抗体的杂交瘤细胞株,分别命名为1G2B6和1G2F10。2株单克隆抗体均为IgG1亚类。腹水单克隆抗体ELISA效价达到1:102 400。Western blot检测结果表明2株单克隆抗体均能与鸭疫里默氏杆菌血清1、2和10型菌株发生特异性结合,而与禽致病性大肠杆菌、沙门氏菌和禽巴氏杆菌菌株无反应性。本研究成功制备了稳定性好、特异性强的鸭疫里默氏杆菌GroEL单克隆抗体,为进一步研制基于抗体检测鸭疫里默氏杆菌抗原的试剂盒奠定了基础。 相似文献
980.