全文获取类型
收费全文 | 531篇 |
免费 | 35篇 |
专业分类
林业 | 34篇 |
农学 | 6篇 |
基础科学 | 6篇 |
178篇 | |
综合类 | 10篇 |
农作物 | 49篇 |
水产渔业 | 46篇 |
畜牧兽医 | 175篇 |
园艺 | 14篇 |
植物保护 | 48篇 |
出版年
2024年 | 4篇 |
2023年 | 5篇 |
2022年 | 15篇 |
2021年 | 26篇 |
2020年 | 15篇 |
2019年 | 26篇 |
2018年 | 24篇 |
2017年 | 18篇 |
2016年 | 23篇 |
2015年 | 27篇 |
2014年 | 30篇 |
2013年 | 29篇 |
2012年 | 43篇 |
2011年 | 36篇 |
2010年 | 30篇 |
2009年 | 17篇 |
2008年 | 29篇 |
2007年 | 20篇 |
2006年 | 35篇 |
2005年 | 20篇 |
2004年 | 24篇 |
2003年 | 20篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1990年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1945年 | 1篇 |
1939年 | 2篇 |
1936年 | 1篇 |
1935年 | 1篇 |
1934年 | 2篇 |
1928年 | 1篇 |
1893年 | 1篇 |
排序方式: 共有566条查询结果,搜索用时 15 毫秒
1.
2.
3.
Lynda Medjkouh Anabela Costa Abderezak Tamendjari Farid Bekdouche Khalida Bouarroudj M. Beatriz P. P. Oliveira 《Phytoparasitica》2018,46(5):595-605
The olive fruit fly, Bactrocera oleae (Rossi), is the major olive pest in the Mediterranean Basin, being responsible for high losses in olive production. The objective of this work was to study the influence of B. oleae infestation on the pomological parameters and nutritive value (lipids, proteins, carbohydrates and ash) of eight olive cultivars (Abani, Aellah, Blanquette de Guelma, Chemlal, Ferkani, Limli, Rougette de Mitidja and Souidi) from Algeria. The results displayed different degrees of susceptibility of the studied cultivars to this pest. Fruit size (weight) and the Fruit weight / stone weight ratio are significantly correlated with the attack. The statistical treatment of the results (PCA and HAC) highlighted different behaviors from the cultivars, concerning the attack. There are some cultivars more susceptible, being the nutritional value also affected. The lipid and protein contents were positively correlated with the attack and the carbohydrates negatively, suggesting a careful choice by the B. oleae. Ovipositional preference of olive fruit fly females and the success of larval development in different olive cultivars are crucial to establishing new approaches in Integrated Pest Management (IPM) against this pest. 相似文献
4.
5.
Miguel Mellado Lucía M. Treviño María I. Chavez Francisco G. Véliz Ulises Macías-Cruz Leonel Avendaño-Reyes José E. García 《Reproduction in domestic animals》2023,58(1):39-47
The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding. 相似文献
6.
Analgesic efficacy of an oral transmucosal spray formulation of meloxicam alone or in combination with tramadol in cats with naturally occurring osteoarthritis 下载免费PDF全文
7.
Gaspar Soria Miguel F. Lavín Iván Martínez‐Tovar Alberto Macías‐Duarte 《Aquaculture Research》2013,44(9):1383-1398
We evaluated recruitment of larvae of catarina scallop, Argopecten ventricosus, in the area of Puerto Peñasco, NE Gulf of California. We moored artificial collectors in six sites from June 2007 to August 2008 and replaced them every 2 months. We used monthly (July 2002–September 2011) sea surface temperature (SST, °C) and surface chlorophyll‐a concentration (SSChl, mg m?3) Aqua/MODIS satellite data to describe seasonal environmental behaviour study area. Also, we recorded bottom temperature at each site every 4 h, and every 2 months measured sea surface salinity, temperature and dissolved oxygen. We used a repeated measures anova to evaluate differences in the number of recruited spat between main factors, and analysed the presence of multimodal spat shell size frequency distributions. Overall, spat recruitment was negatively correlated with seawater temperature and showed higher spat recruitment abundances throughout winter, which is the season with the highest surface chlorophyll a concentration. We estimated multimodal shell size frequency distributions characterized by more than one modal size. The natural collection of A. ventricosus spat on artificial collectors in the area can be successfully performed over a protracted period (November–December to May–June). Our results extend the area where collection of A. ventricosus spat can be successful. 相似文献
8.
Beatriz Gutiérrez‐Crespo Patrick R. Kircher Ines Carrera 《Veterinary radiology & ultrasound》2014,55(3):278-285
The aim of this study was to describe the appearance of the ligamentous structures of the occipitoatlantoaxial (OAA) region in the normal horse by 3 tesla (3T) magnetic resonance imaging (MRI). The MRI images of the longitudinal odontoid ligament, tectorial membrane, dorsal and ventral atlantoaxial ligaments, dorsal atlantooccipital membrane with its reinforcing ligaments, and the lateral atlantooccipital ligaments of 10 horse cadavers were evaluated. All ligaments and membranes were identified in all planes, except for the lateral atlantooccipital ligament in the sagittal plane due to its cranioventrolateral course. All were iso to mildly hypointense to musculature of the neck in T1W with the exception of the tectorial membrane that was moderately hypointense; moderately hypointense in PD‐SPIR, and markedly hypointense (isointense to cortical bone) in T2W. The PD‐SPIR was the best sequence to identify all ligaments and membranes from their cranial and caudal attachments. The longitudinal odontoid ligament, ventral atlantoaxial ligament, and reinforcing bands of the dorsal atlantooccipital membrane presented a characteristic striped heterogeneous signal behavior thought to be due to fibrocartilaginous content. The remaining ligaments and membranes showed homogeneous signal intensity. Special anatomical features in this species such as the fan‐shaped longitudinal odontoid ligament, absence of the transverse ligament and presence of the ventral atlantoaxial ligament were documented. Ligamentous structures that stabilize the equine OAA region were described with MRI in this study and these findings could serve as an anatomic reference for those cases where instability of this region is suspected. 相似文献
9.
Letícia Beatriz Matter Nicolle Lima Barbieri Marcel Nordhoff Christa Ewers Fabiana Horn 《Veterinary microbiology》2011
Avian pathogenic Escherichia coli (APEC) are responsible for extraintestinal diseases, called colibacillosis, in avian species. The most severe manifestation of the disease is colisepticemia that usually starts at the respiratory tract and may result in bird death. However, it is not yet clear how APEC cross the respiratory epithelium and get into the bloodstream. In this work, we studied the interaction between 8 APEC strains (UEL31, UEL17, UEL13, UEL29, MT78, IMT5155, IMT2470, A2363) and a chicken non-phagocytic cell, the fibroblast CEC-32 cell line. We investigated the association profile, the invasion capability, the cytotoxicity effect and the induction of caspase-3/7 activation in an attempt to understand the way the pathogen gains access to the host bloodstream. Association to cells was determined after 1 h of infection, while cell invasion was determined after 4 and 24 h of infection. The cytotoxic effect of bacterial infection was measured by lactate dehydrogenase (LDH) release and the activation of the apoptotic program was verified by caspase-3/7 activation. Also, the presence of genes for adhesins, invasins and other related virulence-associated factors was verified by PCR. All bacterial strains showed similarity in relation to adhesion, LDH release and caspase-3/7 activation. However, one APEC strain, MT78, showed high invasion capability, comparable to the invasive Salmonella typhimurium strain SL1344. Since an APEC strain was capable of invading non-phagocytic cells in vitro, the same may be happening with the epithelial cells of the avian respiratory tract in vivo. CEC-32 monolayers can also provide a useful experimental model to study the molecular mechanisms used by APEC to invade non-phagocytic cells. 相似文献
10.
Kara L. Moreno Elizabeth M. Scallan Beatriz P. Monteiro Paulo V. Steagall Bradley T. Simon 《Veterinary anaesthesia and analgesia》2021,48(4):570-576
ObjectiveTo evaluate the thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats.Study designRandomized, blinded, placebo-controlled crossover study design.AnimalsA total of six purpose-bred, adult female ovariohysterectomized Domestic Short Hair cats.MethodsCats were allocated into three treatments each consisting of two injections, subcutaneous then intravenous (IV) administration, 2 hours apart: treatment SS, two injections of 0.9% saline; treatment BS, buprenorphine (0.24 mg kg–1, 1.8 mg mL–1) and saline; and treatment BH, buprenorphine (0.24 mg kg–1) and hydromorphone (0.1 mg kg–1). Skin temperature (ST) and thermal threshold (TT) were recorded before (baseline) and for 24 hours following first injection. TT data were analyzed using mixed linear models and a Benjamini–Hochberg sequential adjustment procedure (p < 0.05).ResultsThere were no significant differences among treatments for baseline ST and TT values, treatment SS over time and between treatments BS and BH. Compared with baseline, TT was significantly increased at all time points in treatments BH and BS except at 2 hours in treatment BS. TT was significantly higher than SS at 3–18 hours and 4–12 hours for treatments BS and BH, respectively. Maximal increases in TT were 47.5 °C at 2 hours, 53.9 °C at 3 hours and 52.4 °C at 6 hours in treatments SS, BS and BH, respectively.Conclusions and clinical relevanceAdministration of IV hydromorphone following high-concentration buprenorphine provided no additional antinociception and decreased the duration of effect when compared with high-concentration buprenorphine alone. Alternative analgesics should be considered if additional analgesia is required after administration of high-concentration buprenorphine. 相似文献