全文获取类型
收费全文 | 3670篇 |
免费 | 156篇 |
国内免费 | 3篇 |
专业分类
林业 | 238篇 |
农学 | 93篇 |
基础科学 | 27篇 |
633篇 | |
综合类 | 586篇 |
农作物 | 119篇 |
水产渔业 | 330篇 |
畜牧兽医 | 1513篇 |
园艺 | 102篇 |
植物保护 | 188篇 |
出版年
2024年 | 5篇 |
2023年 | 16篇 |
2022年 | 35篇 |
2021年 | 67篇 |
2020年 | 72篇 |
2019年 | 91篇 |
2018年 | 86篇 |
2017年 | 100篇 |
2016年 | 84篇 |
2015年 | 59篇 |
2014年 | 91篇 |
2013年 | 142篇 |
2012年 | 218篇 |
2011年 | 280篇 |
2010年 | 166篇 |
2009年 | 141篇 |
2008年 | 278篇 |
2007年 | 276篇 |
2006年 | 263篇 |
2005年 | 273篇 |
2004年 | 252篇 |
2003年 | 215篇 |
2002年 | 195篇 |
2001年 | 28篇 |
2000年 | 24篇 |
1999年 | 31篇 |
1998年 | 28篇 |
1997年 | 24篇 |
1996年 | 22篇 |
1995年 | 28篇 |
1994年 | 18篇 |
1993年 | 25篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 14篇 |
1988年 | 18篇 |
1987年 | 28篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1979年 | 2篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1973年 | 4篇 |
1971年 | 2篇 |
1938年 | 2篇 |
1904年 | 2篇 |
排序方式: 共有3829条查询结果,搜索用时 15 毫秒
181.
Ashley B Saunders DVM Diplomate ACVIM rew S Hanzlicek DVM Elizabeth A Martinez DVM Diplomate ACVA Mark J Stickney DVM Jörg M Steiner Dr.med.vet. PhD Diplomate ACVIM Diplomate ECVIM-CA Jan S Suchodolski Dr.med.vet. PhD & Geoffery T Fosgate† DVM PhD Diplomate ACVPM 《Veterinary anaesthesia and analgesia》2009,36(5):449-456
ObjectiveTo report serum cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs anesthetized for elective surgery using two anesthetic protocols.Study designProspective, randomized clinical study.AnimalsTwenty client-owned dogs presenting for elective ovariohysterectomy or castration.MethodsThe dogs were randomized into two groups. All dogs were premedicated with glycopyrrolate (0.011 mg kg?1) and hydromorphone (0.1 mg kg?1) IM approximately 30 minutes prior to induction of anesthesia. Anesthesia in dogs in group 1 was induced with propofol (6 mg kg?1) IV to effect and in dogs in group 2 with diazepam (0.2 mg kg?1) IV followed by etomidate (2 mg kg?1) IV to effect. For maintenance of anesthesia, group 1 received sevoflurane (adjustable vaporizer setting 0.5–4%) and group 2 received a combination of fentanyl (0.8 μg kg?1 minute?1) and midazolam (8.0 μg kg?1 minute?1) IV plus sevoflurane (adjustable vaporizer setting 0.5–4%) to maintain anesthesia. Serum cTnI and CRP concentrations were measured at baseline and 6, 18, and 24 hours post-anesthetic induction. Biochemical analysis was performed at baseline. Lactate was obtained at baseline and 6 hours post-anesthetic induction. Heart rate and mean arterial blood pressure were measured intra-operatively.ResultsBaseline serum cTnI and CRP concentrations were comparable between groups. A significant difference in serum cTnI or CRP concentrations was not detected post-operatively between groups at any time point. Serum CRP concentrations were significantly increased post-anesthetic induction in both groups, which was attributed to surgical trauma.Conclusions and clinical relevanceThere was no significant difference in serum cTnI and CRP concentrations between anesthetic protocols. Further investigation in a larger number of dogs is necessary to confirm the current findings. 相似文献
182.
Deidre K Fontenot Scott P Terrell Michele Miller Patricia K Robbins Mark Stetter Martha Weber 《Journal of zoo and wildlife medicine》2005,36(3):509-511
A 10-yr-old male gorilla (Gorilla gorilla gorilla) with a history of conspecific bite wounds was evaluated for acute onset of depression, anorexia, and right hemiparesis. The animal was immobilized for diagnostic examination and treatment for suspected toxic shock from a necrotizing, emphysematous wound infection, but was euthanized due to complications during recovery. Gross and histopathologic examination revealed acute necrotizing myositis, fasciitis, cellulitis, and emphysema in the affected wound area, with large numbers of large Gram-positive rods among necrotic muscle fibers. Severe pulmonary edema with airways containing fibrin, acute hemorrhage in multiple body sites, thrombosis in blood vessels in the skeletal muscle, liver, and lung, and lymph node hyperplasia with lymphoid necrosis and hemorrhage. Immunohistochemical fluorescent antibody staining of muscle from the wound site was positive for 相似文献
183.
184.
185.
186.
A juvenile cheetah (Acinonyx jubatus) died with rapidly progressive pyrexia, tachypnea, abdominal effusion, and hepatomegaly. Postmortem examination revealed lesions consistent with acute disseminated infection with Toxoplasma gondii. The presence of this organism was confirmed in multiple organs by immunohistochemistry and polymerase chain reaction. To the best of our knowledge, we propose this to be the first reported case of primary acute disseminated toxoplasmosis in a cheetah. 相似文献
187.
Hadi Atashi Mazdak Salavati Jenne De Koster Jim Ehrlich Mark Crowe Geert Opsomer the GplusE consortium Miel Hostens 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(3):292-304
The aim of this study was to identify genomic regions associated with 305-day milk yield and lactation curve parameters on primiparous (n = 9,910) and multiparous (n = 11,158) Holstein cows. The SNP solutions were estimated using a weighted single-step genomic BLUP approach and imputed high-density panel (777k) genotypes. The proportion of genetic variance explained by windows of 50 consecutive SNP (with an average of 165 Kb) was calculated, and regions that accounted for more than 0.50% of the variance were used to search for candidate genes. Estimated heritabilities were 0.37, 0.34, 0.17, 0.12, 0.30 and 0.19, respectively, for 305-day milk yield, peak yield, peak time, ramp, scale and decay for primiparous cows. Genetic correlations of 305-day milk yield with peak yield, peak time, ramp, scale and decay in primiparous cows were 0.99, 0.63, 0.20, 0.97 and −0.52, respectively. The results identified three windows on BTA14 associated with 305-day milk yield and the parameters of lactation curve in primi- and multiparous cows. Previously proposed candidate genes for milk yield supported by this work include GRINA, CYHR1, FOXH1, TONSL, PPP1R16A, ARHGAP39, MAF1, OPLAH and MROH1, whereas newly identified candidate genes are MIR2308, ZNF7, ZNF34, SLURP1, MAFA and KIFC2 (BTA14). The protein lipidation biological process term, which plays a key role in controlling protein localization and function, was identified as the most important term enriched by the identified genes. 相似文献
188.
189.
190.