全文获取类型
| 收费全文 | 73419篇 |
| 免费 | 4204篇 |
| 国内免费 | 34篇 |
专业分类
| 林业 | 3199篇 |
| 农学 | 2404篇 |
| 基础科学 | 468篇 |
| 8713篇 | |
| 综合类 | 12037篇 |
| 农作物 | 2826篇 |
| 水产渔业 | 3542篇 |
| 畜牧兽医 | 38636篇 |
| 园艺 | 838篇 |
| 植物保护 | 4994篇 |
出版年
| 2018年 | 975篇 |
| 2017年 | 1084篇 |
| 2016年 | 1005篇 |
| 2015年 | 850篇 |
| 2014年 | 1056篇 |
| 2013年 | 2757篇 |
| 2012年 | 1959篇 |
| 2011年 | 2286篇 |
| 2010年 | 1540篇 |
| 2009年 | 1567篇 |
| 2008年 | 2334篇 |
| 2007年 | 2226篇 |
| 2006年 | 2044篇 |
| 2005年 | 1978篇 |
| 2004年 | 1853篇 |
| 2003年 | 1997篇 |
| 2002年 | 1816篇 |
| 2001年 | 2243篇 |
| 2000年 | 2194篇 |
| 1999年 | 1748篇 |
| 1998年 | 714篇 |
| 1997年 | 776篇 |
| 1996年 | 685篇 |
| 1995年 | 865篇 |
| 1994年 | 735篇 |
| 1993年 | 734篇 |
| 1992年 | 1493篇 |
| 1991年 | 1636篇 |
| 1990年 | 1603篇 |
| 1989年 | 1606篇 |
| 1988年 | 1495篇 |
| 1987年 | 1457篇 |
| 1986年 | 1537篇 |
| 1985年 | 1453篇 |
| 1984年 | 1270篇 |
| 1983年 | 1063篇 |
| 1982年 | 749篇 |
| 1979年 | 1171篇 |
| 1978年 | 889篇 |
| 1977年 | 841篇 |
| 1976年 | 800篇 |
| 1975年 | 829篇 |
| 1974年 | 1030篇 |
| 1973年 | 1071篇 |
| 1972年 | 1018篇 |
| 1971年 | 951篇 |
| 1970年 | 927篇 |
| 1969年 | 899篇 |
| 1968年 | 755篇 |
| 1967年 | 844篇 |
排序方式： 共有10000条查询结果，搜索用时 265 毫秒
971.
972.
973.
974.
A 6‐year‐old, intact, male English cocker spaniel was referred for treatment of chronic conjunctivitis and unilateral keratitis. The dog was diagnosed with bilateral immune‐mediated keratoconjunctivitis sicca, treated with topical cyclosporine 0·2% ointment and sodium hyaluronate eye drops and improved considerably. After 2 months, pulmonic stenosis was diagnosed, and the dog commenced treatment with oral atenolol; the ophthalmological disease worsened dramatically within a few days. The ophthalmic signs rapidly improved after discontinuation of atenolol, and there was bilateral complete remission after 3 weeks. No oral β‐blocker therapy was reintroduced, and thereafter, keratoconjunctivitis sicca was well‐controlled with topical therapy. 相似文献
975.
976.
977.
978.
Use of Non‐invasive Methods for Evaluating the Testicular Biometry in Collared Peccaries (Pecari tajacu Linnaeus, 1758) 
下载免费PDF全文
下载免费PDF全文 G. C. X. Peixoto M. A. Silva G. L. Lima L. B. Campos A. L. C. Paiva V. V. Paula A. R. F. Ricarte A. R. Silva 《Anatomia, histologia, embryologia》2016,45(1):60-66
The aim of this study was to compare the accuracy of two methods used to estimate testicular volume in the collared peccary. Calliper and ultrasonographic measurements of testicular dimensions (length, width and height) of both testes were taken on five adult collared peccaries. The testicular volume was calculated by Lambert's empiric formula: length (L) × width (W) × height (H) × 0.71, the formula of an ellipsoid L × W × H × 0.52, and Hansen's formula: L × W2 × 0.52. The calculated volumes were then compared with the actual ones, which were estimated by water displacement. The mean of true testicular volume was 22.65 ± 1.52 ml. Lambert's formula estimated testicular volume more accurately when ultrasound measurements were taken. However, when the calliper was the methodology used, the results were closest to the true volume, especially when Ellipsoid formula and Hansen's formula were applied, and underestimated the true volumes by 1.53 ± 1.75 ml and 1.53 ± 1.65 ml, respectively. This specific application of technologies in wild animals has the potential to revolutionize the selection process for the collared peccary entering artificial insemination or natural breeding programmes. 相似文献
979.
L. M. Leal H. M. G. de Freitas T. H. C. Sasahara M. R. F. Machado 《Anatomia, histologia, embryologia》2016,45(2):154-157
This study aims to describe the origin and distribution of the hindlimb arterial vessels. Five adult lowland pacas (Cuniculus paca) were used. Stained and diluted latex was injected, caudally to the aorta. After fixation in 10% paraformaldehyde for 72 h, we dissected to visualize and identify the vessels. It was found out that the vascularization of the hindlimb in lowland paca derives from the terminal branch of the abdominal aorta. The common iliac artery divides into external iliac and internal iliac. The external iliac artery emits the deep iliac circumflex artery, the pudendal epigastric trunk, the deep femoral artery; the femoral artery originates the saphenous artery, it bifurcates into cranial and caudal saphenous arteries. Immediately after the knee joint, the femoral artery is called popliteal artery, which divides into tibial cranial and tibial caudal arteries at the level of the crural inter‐osseous space. The origin and distribution of arteries in the hindlimb of lowland paca resembles that in other wild rodents, as well as in the domestic mammals. 相似文献
980.