全文获取类型
收费全文 | 923篇 |
免费 | 51篇 |
国内免费 | 2篇 |
专业分类
林业 | 31篇 |
农学 | 39篇 |
基础科学 | 5篇 |
140篇 | |
综合类 | 120篇 |
农作物 | 49篇 |
水产渔业 | 33篇 |
畜牧兽医 | 484篇 |
园艺 | 17篇 |
植物保护 | 58篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 24篇 |
2019年 | 22篇 |
2018年 | 15篇 |
2017年 | 20篇 |
2016年 | 20篇 |
2015年 | 12篇 |
2014年 | 13篇 |
2013年 | 43篇 |
2012年 | 36篇 |
2011年 | 42篇 |
2010年 | 40篇 |
2009年 | 19篇 |
2008年 | 38篇 |
2007年 | 43篇 |
2006年 | 41篇 |
2005年 | 46篇 |
2004年 | 34篇 |
2003年 | 39篇 |
2002年 | 52篇 |
2001年 | 21篇 |
2000年 | 19篇 |
1999年 | 23篇 |
1998年 | 12篇 |
1997年 | 18篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 13篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1972年 | 5篇 |
1967年 | 4篇 |
1943年 | 5篇 |
排序方式: 共有976条查询结果,搜索用时 15 毫秒
971.
Nickolas Henry Williams Dean Downes Geoff Tilyard Paul Harrison Peter A. Vaillancourt René E. Potts Brad 《New Forests》2020,51(1):137-158
New Forests - Eucalyptus globulus is widely grown for pulpwood production in temperate regions of the world. However, there is increasing interest in using it for solid-wood products. We studied... 相似文献
972.
Vengust M Staempfli H Prescott JF 《The Canadian veterinary journal. La revue veterinaire canadienne》2002,43(9):706-708
A 10-year-old warmblood gelding was evaluated for intermittent pyrexia, dullness, weight loss, and progressive respiratory disease. Multifocal necrotic pneumonia and pleuritis due to Rhodococcus equi infection was diagnosed. Case management is discussed, as well as factors that may have led to this rare cause of pleuropneumonia in an adult horse. 相似文献
973.
Seeram NP Adams LS Zhang Y Lee R Sand D Scheuller HS Heber D 《Journal of agricultural and food chemistry》2006,54(25):9329-9339
Berry fruits are widely consumed in our diet and have attracted much attention due to their potential human health benefits. Berries contain a diverse range of phytochemicals with biological properties such as antioxidant, anticancer, anti-neurodegerative, and anti-inflammatory activities. In the current study, extracts of six popularly consumed berries--blackberry, black raspberry, blueberry, cranberry, red raspberry and strawberry--were evaluated for their phenolic constituents using high performance liquid chromatography with ultraviolet (HPLC-UV) and electrospray ionization mass spectrometry (LC-ESI-MS) detection. The major classes of berry phenolics were anthocyanins, flavonols, flavanols, ellagitannins, gallotannins, proanthocyanidins, and phenolic acids. The berry extracts were evaluated for their ability to inhibit the growth of human oral (KB, CAL-27), breast (MCF-7), colon (HT-29, HCT116), and prostate (LNCaP) tumor cell lines at concentrations ranging from 25 to 200 micro g/mL. With increasing concentration of berry extract, increasing inhibition of cell proliferation in all of the cell lines were observed, with different degrees of potency between cell lines. The berry extracts were also evaluated for their ability to stimulate apoptosis of the COX-2 expressing colon cancer cell line, HT-29. Black raspberry and strawberry extracts showed the most significant pro-apoptotic effects against this cell line. The data provided by the current study and from other laboratories warrants further investigation into the chemopreventive and chemotherapeutic effects of berries using in vivo models. 相似文献
974.
975.
The ringed seal (Phoca hispida), as well as other seals, exhibit some unique anatomical properties when compared to their terrestrial counterparts. In the ringed seal, the most conspicuous adaptation is the aortic bulb, a large dilatation of the ascending aorta, which is comparable to that found in other seal species and marine mammals. Coronary arteries are similar to those of terrestrial mammals. The branches of the ascending aorta (brachiocephalic trunk, left common carotid artery and left subclavian artery) are similar to those of higher primates and man. The pulmonary trunk originates from the right ventricle near the ventral midline of the thorax. The peculiarities of the venous system are three pulmonary veins, a pericardial venous plexus, a caval sphincter, a hepatic sinus with paired caudal vena cavae and a large extradural venous system. Generally, three pulmonary veins (right, left, middle) empty into the left atrium. The right and left pulmonary veins drain the cranial and middle lung lobes of their respective lung, while the middle pulmonary vein drains both caudal lung lobes and the accessory lobe. The pericardial venous plexus lies on the pericardial pleura on the auricular (ventral) surface the heart. The azygous vein is formed from the union of right and left azygous veins near the 5th thoracic vertebra. The caval sphincter surrounds the caudal vena cava as it passes through the diaphragm. Caudal to the diaphragm, the vena cava is dilated excessively (the hepatic sinus) and near the kidneys it is biphid. Cardiovascular physiological studies have shown some of these anatomical variations, especially of the venous system and the ascending aorta, to be modifications for diving. 相似文献
976.