全文获取类型
收费全文 | 67645篇 |
免费 | 3927篇 |
国内免费 | 86篇 |
专业分类
林业 | 2904篇 |
农学 | 2245篇 |
基础科学 | 373篇 |
7970篇 | |
综合类 | 10733篇 |
农作物 | 2466篇 |
水产渔业 | 3372篇 |
畜牧兽医 | 36356篇 |
园艺 | 817篇 |
植物保护 | 4422篇 |
出版年
2019年 | 770篇 |
2018年 | 1137篇 |
2017年 | 1171篇 |
2016年 | 1088篇 |
2015年 | 965篇 |
2014年 | 1102篇 |
2013年 | 3008篇 |
2012年 | 2086篇 |
2011年 | 2457篇 |
2010年 | 1492篇 |
2009年 | 1503篇 |
2008年 | 2233篇 |
2007年 | 2209篇 |
2006年 | 2051篇 |
2005年 | 1888篇 |
2004年 | 1786篇 |
2003年 | 1795篇 |
2002年 | 1757篇 |
2001年 | 2017篇 |
2000年 | 1991篇 |
1999年 | 1635篇 |
1998年 | 676篇 |
1997年 | 656篇 |
1995年 | 684篇 |
1994年 | 631篇 |
1993年 | 601篇 |
1992年 | 1283篇 |
1991年 | 1413篇 |
1990年 | 1307篇 |
1989年 | 1321篇 |
1988年 | 1214篇 |
1987年 | 1184篇 |
1986年 | 1233篇 |
1985年 | 1243篇 |
1984年 | 993篇 |
1983年 | 937篇 |
1982年 | 610篇 |
1979年 | 920篇 |
1978年 | 718篇 |
1977年 | 712篇 |
1976年 | 724篇 |
1975年 | 727篇 |
1974年 | 886篇 |
1973年 | 862篇 |
1972年 | 833篇 |
1971年 | 742篇 |
1970年 | 793篇 |
1969年 | 744篇 |
1968年 | 660篇 |
1967年 | 668篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
Use of Non‐invasive Methods for Evaluating the Testicular Biometry in Collared Peccaries (Pecari tajacu Linnaeus, 1758)
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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
994.
Galanin is Co‐Expressed with Substance P,Calbindin and Corticotropin‐Releasing Factor (CRF) in The Enteric Nervous System of the Wild Boar (Sus scrofa) Small Intestine
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Galanin is a neuropeptide widely present in the enteric nervous system of numerous animal species and exhibiting neurotransmittery/neuromodulatory roles. Colocalization patterns of galanin with substance P (SP), corticotropin‐releasing factor (CRF) and calbindin were studied in the small intestine of the wild boar using immunofluorescence technique. We demonstrated the presence of SP in substantial populations of galanin‐immunoreactive (IR) submucous neurons. Additionally, different amounts of nerve fibres exhibiting simultaneous presence of galanin and SP were noted in the small intestinal smooth musculature, submucous ganglia, lamina muscularis mucosae and mucosa. In the wild boar duodenum, jejunum and ileum, the co‐expression of galanin and calbindin was limited to minor populations of submucous neurons only. Single galanin‐/CRF‐IR nerve fibres were exclusively present in the duodenal and jejunal (but not ileal) mucosa. These results strongly suggest that galanin participates in neuronal control of the wild boar small intestine also by functional co‐operation with other biologically active neuropeptides. 相似文献
995.
Angiogenesis in The Ovary – The Most Important Regulatory Event for Follicle and Corpus Luteum Development and Function in Cow – An Overview
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In the ovary, the development of new capillaries from pre‐existing ones (angiogenesis) is a complex event regulated by numerous local factors. The dominant regulators of angiogenesis in ovarian follicles and corpora lutea are the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), insulin‐like growth factor (IGF), angiopoietin (ANPT) and hypoxia‐inducible factor (HIF) family members. Antral follicles in our study were classified according to the oestradiol‐17‐beta (E2) content in follicular fluid (FF) and were divided into five classes (E2 < 0.5, 0.5–5, 5–20, 20–180 and >180 ng/ml FF). The corresponding sizes of follicles were 5–7, 8–10, 10–13, 12–14 and >14 mm, respectively. Follicle tissue was separated in theca interna (TI) and granulosa cells (GC). The corpora lutea (CL) in our study were assigned to the following stages: days 1–2, 3–4, 5–7, 8–12 13–16 and >18 of the oestrous cycle and months 1–2, 3–4, 6–7 and >8 of pregnancy. The dominant regulators were measured at mRNA and protein expression levels; mRNA was quantified by RT‐qPCR, hormone concentrations by RIA or EIA and their localization by immunohistochemistry. The highest expression for VEGF‐A, FGF‐2, IGF‐1 and IGF‐2, ANPT‐2/ANPT‐1 and HIF‐1‐alpha was found during final follicle maturation and in CL during the early luteal phase (days 1–4) followed by a lower plateau afterwards. The results suggest the importance of these factors for angiogenesis and maintenance of capillary structures for final follicle maturation, CL development and function. 相似文献
996.
Rémi Froment Christian Bédard 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2016,45(3):459-465
This is the report of a 5‐year‐old male neutered Great Dane with an extreme leukocytosis (544.9 × 109 cells/L; RI 5.2–13.9 × 109 cells/L) characterized by highly atypical round cells. Cellular morphologic features such as cytoplasmic membrane blebs, a high nuclear‐to‐cytoplasmic ratio, and nuclear indentations and irregularities and large nucleoli, as well as immunocytochemistry for CD3 and CD79, myeloperoxidase cytochemistry, and clonality testing were not conclusive for myeloid or lymphoid origin. Marked alkaline hyperphosphatasemia was present at the first visit (2783.0 U/L; RI 6–80.0 U/L), followed by a 5‐fold increase (14,000 U/L) a week later, identified as being mostly contributed by the bone‐ALP isoform (11,062 U/L; RI 0–30 U/L). In addition, the atypical leukocytes were strongly positive for cytoplasmic ALP activity. In vitro lysis of a heparin blood sample resulted in a 1.7‐fold increase of ALP activity, supporting the origin of the hyperphosphatasemia at least in part from the leukemic cell population. To the authors’ knowledge, this is a unique case of alkaline hyperphosphatasemia, due at least to a leukemic cell population producing a bone‐ALP isoform, regardless of the exact nature of the leukemia. 相似文献
997.
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
998.
Magnetic Resonance Imaging of the Dorsal Proximal Synovial Plica of the Equine Metacarpo‐/Metatarsophalangeal Joint
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S. Hauspie K. Vanderperren I. Gielen B. Pardon K. Kromhout A. Martens J. H. Saunders 《Anatomia, histologia, embryologia》2016,45(1):19-27
A synovial plica is present at the dorsoproximal aspect of the fetlock joint. The objective of this study was to describe the location of the synovial plica during induced hyperextension using Magnetic Resonance Imaging. For this study 20 cadaver limbs from five Warmblood horses were used. Measurements were made of the dorsal; palmar/plantar length and the thickness of the plica with the joint in a normal position. During induced hyperextension of the joint, the position of the plica was described; the dorsal angle of extension and angle of contact between the proximal phalanx (P1) and the condyle were measured. The dorsal length differed between front/hind limbs and between the medial/lateral aspect of the joint. The angle of contact between P1 and condyle differed between front/hind limbs; between the lateral and medial aspect of the joint and between different positions of the plica. Four different positions of the plica were observed: shortened with the tip curved towards palmar/plantar; projecting distally; projecting towards dorsal and projecting distally with the tip interposed between P1 and the condyle. During induced hyperextension, a close relation is present between the synovial plica, P1 and the condyle with a variable position of the plica; which is suggestive for a contact interface between P1 and the metacarpal/metatarsal bone. However the plica does not seem to act consistently as a cushioning surface. 相似文献
999.
1000.