全文获取类型
收费全文 | 12699篇 |
免费 | 3669篇 |
国内免费 | 10篇 |
专业分类
林业 | 835篇 |
农学 | 666篇 |
基础科学 | 56篇 |
2829篇 | |
综合类 | 803篇 |
农作物 | 362篇 |
水产渔业 | 2872篇 |
畜牧兽医 | 6052篇 |
园艺 | 185篇 |
植物保护 | 1718篇 |
出版年
2023年 | 34篇 |
2022年 | 66篇 |
2021年 | 237篇 |
2020年 | 581篇 |
2019年 | 1153篇 |
2018年 | 1011篇 |
2017年 | 1063篇 |
2016年 | 1060篇 |
2015年 | 911篇 |
2014年 | 956篇 |
2013年 | 1277篇 |
2012年 | 801篇 |
2011年 | 887篇 |
2010年 | 856篇 |
2009年 | 481篇 |
2008年 | 619篇 |
2007年 | 446篇 |
2006年 | 498篇 |
2005年 | 480篇 |
2004年 | 437篇 |
2003年 | 406篇 |
2002年 | 434篇 |
2001年 | 158篇 |
2000年 | 172篇 |
1999年 | 102篇 |
1998年 | 77篇 |
1997年 | 72篇 |
1996年 | 59篇 |
1995年 | 73篇 |
1994年 | 45篇 |
1993年 | 54篇 |
1992年 | 43篇 |
1991年 | 42篇 |
1990年 | 54篇 |
1989年 | 53篇 |
1988年 | 40篇 |
1987年 | 32篇 |
1986年 | 26篇 |
1985年 | 39篇 |
1984年 | 29篇 |
1983年 | 44篇 |
1982年 | 33篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1978年 | 25篇 |
1977年 | 26篇 |
1974年 | 21篇 |
1973年 | 22篇 |
1970年 | 21篇 |
1968年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Kanako Muta Takako Miyabe‐Nishiwaki Kenichi Masui Isao Yajima Tomoya Iizuka Akihisa Kaneko Ryohei Nishimura 《Journal of veterinary pharmacology and therapeutics》2021,44(1):18-27
The objectives of this study were (a) to establish a population pharmacokinetic model and (b) to investigate the clinical and physiological effects of a single bolus dose of propofol in common marmosets. In Study 1, pharmacokinetic analysis was performed in six marmosets under sevoflurane anaesthesia. 8 mg/kg of propofol was administrated at a rate of 4 mg kg?1 min?1. Blood samples were collected 2, 5, 15, 30, 60, 90, 120 or 180 min after starting propofol administration. Plasma concentration was measured, and population pharmacokinetic modelling was performed. A two‐compartment model was selected as the final model. The population pharmacokinetic parameters were as follows: V1 = 1.14 L, V2 = 77.6 L, CL1 = 0.00182 L/min, CL2 = 0.0461 L/min. In Study 2, clinical and physiological parameters were assessed and recorded every 2 min after 12 mg/kg of propofol was administrated at a rate of 4 mg kg?1 min?1. Immobilization was sustained for 5 min following propofol administration without apparent bradycardia. While combination of propofol and sevoflurane caused apnoea in Study 1, apnoea was not observed following single administration of propofol in Study 2. These data provide bases for further investigation on intravenous anaesthesia using propofol in common marmosets. 相似文献
82.
83.
84.
Josephine A. Dornbusch Laura E. Selmic Pin‐Chieh Huang Jonathan P. Samuelson Eric M. McLaughlin Vincent A. Wavreille Jessica A. Ogden Brittany Abrams Alex Kalamaras Eric Green Eric T. Hostnik Lincoln Every Jason A. Fuerst Ryan Jennings Christopher Premanandan Joshua N. Lorbach Sarah C. Linn Aneesh Alex Janet E. Sorrells Lingxiao Yang Stephen A. Boppart 《Veterinary surgery : VS》2021,50(1):111-120
85.
86.
87.
Thomas R. De Ridder Justine E. Campbell Cheryl Burke‐Schwarz David Clegg Emily L. Elliot Samuel Geller Wendy Kozak Stephen T. Pittenger Jennifer B. Pruitt Jocelyn Riehl Julie White Melissa L. Wiest Chad M. Johannes John Morton Pamela D. Jones Peter F. Schmidt Victoria Gordon Paul Reddell 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2021,35(1):415-429
88.
89.
Jakub Vozaf Alexander V. Makarevich Andrej Balazi Jaromir Vasicek Andrea Svoradova Lucia Olexikova Peter Chrenek 《Animal Science Journal》2021,92(1):e13670
The aim of our study was to examine effects of the length of semen equilibration as well as two freezing techniques on ram sperm post-thaw quality. The ejaculates of Wallachian sheep rams (n = 12) were collected by an electro-ejaculation, equilibrated in a Triladyl® (0, 2, 4, 6, and 8 h) containing glycerol and egg yolk and frozen by programmable freezing (PF) or manual freezing (MF). After thawing, sperm samples were subjected to the motility (computer-assisted sperm analysis [CASA]), viability (SYBR-14/PI), and fertilizing ability (FA) (in vitro penetration/fertilization test on bovine oocytes) assays. It was found that the equilibration of 6 h (E-6) ensured higher post-thaw sperm motility and progressive movement compared with other lengths tested, irrespective of a freezing technique. The E-6 sperm viability did not differ between PF and MF but was lower (P < 0.05) than control. Sperm FA (E-6) was similar in PF (60.44%) and MF (62%) but slightly lower than in fresh (72.8%). Our data demonstrate that the use of MF was comparable with PF, which can be applied in the field conditions without need in a piece of cost-expensive equipment, which can greatly benefit the gene bank of animal genetic resources. 相似文献
90.
Wei‐Shan Lee Jih‐Jong Lee Albert Taiching Liao Chia‐Lien Kao Shang‐Lin Wang 《Veterinary and comparative oncology》2021,19(1):53-60
The majority of the known prognostic factors in dogs with lymphoma have been evaluated before treatment commences or at the time of diagnosis. Prognostic factors evaluated during the initial phase of treatment are less described but may provide important clinical information. In this retrospective study, 82 canine lymphoma patients were categorized according to the weight change between diagnosis and after 5 weeks of chemotherapy. Dogs that gained greater than 5% or lost greater than 5% of initial body weight were categorized as increased‐ or decreased‐weight groups, respectively. Those in which weight changed less than 5% were categorized as the maintained‐weight group. The median progression‐free survival (PFS) in the increased‐weight group, maintained‐weight group and decreased‐weight group was 226, 256 and 129 days, respectively. The decreased‐weight group had significantly shorter PFS than the increased and maintained groups (P = .023, P = .003, respectively). The median survival time (ST) in the increased‐weight group, maintained‐weight group and decreased‐weight group was 320, 339 and 222 days, respectively. There was no significant difference in ST among the three groups (P = .128). In Cox‐regression results, weight change group and initial body weight were significant risk factors associated to PFS (P = .007, P = .001, respectively) while only patient's initial body weight was a significant risk factor to ST (P = .013). In conclusion, evaluation of initial body weight and weight changes over time can provide valuable information regarding PFS and ST in dogs with multicentric lymphoma. 相似文献