全文获取类型
收费全文 | 1542篇 |
免费 | 109篇 |
国内免费 | 31篇 |
专业分类
林业 | 41篇 |
农学 | 43篇 |
基础科学 | 10篇 |
192篇 | |
综合类 | 248篇 |
农作物 | 53篇 |
水产渔业 | 55篇 |
畜牧兽医 | 948篇 |
园艺 | 26篇 |
植物保护 | 66篇 |
出版年
2022年 | 23篇 |
2021年 | 22篇 |
2020年 | 20篇 |
2019年 | 30篇 |
2018年 | 34篇 |
2017年 | 50篇 |
2016年 | 36篇 |
2015年 | 36篇 |
2014年 | 42篇 |
2013年 | 78篇 |
2012年 | 83篇 |
2011年 | 64篇 |
2010年 | 55篇 |
2009年 | 49篇 |
2008年 | 58篇 |
2007年 | 73篇 |
2006年 | 54篇 |
2005年 | 67篇 |
2004年 | 56篇 |
2003年 | 58篇 |
2002年 | 43篇 |
2001年 | 44篇 |
2000年 | 34篇 |
1999年 | 22篇 |
1998年 | 23篇 |
1996年 | 11篇 |
1995年 | 16篇 |
1994年 | 11篇 |
1993年 | 17篇 |
1992年 | 20篇 |
1991年 | 24篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 28篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 23篇 |
1983年 | 15篇 |
1979年 | 16篇 |
1978年 | 14篇 |
1977年 | 21篇 |
1975年 | 14篇 |
1974年 | 13篇 |
1973年 | 14篇 |
1972年 | 11篇 |
1971年 | 11篇 |
1970年 | 13篇 |
1969年 | 19篇 |
1966年 | 11篇 |
排序方式: 共有1682条查询结果,搜索用时 875 毫秒
11.
12.
Freeman RG Grabar KC Allison KJ Bright RM Davis JA Guthrie AP Hommer MB Jackson MA Smith PC Walter DG Natan MJ 《Science (New York, N.Y.)》1995,267(5204):1629-1632
The self-assembly of monodisperse gold and silver colloid particles into monolayers on polymer-coated substrates yields macroscopic surfaces that are highly active for surface-enhanced Raman scattering (SERS). Particles are bound to the substrate through multiple bonds between the colloidal metal and functional groups on the polymer such as cyanide (CN), amine (NH(2)), and thiol (SH). Surface evolution, which can be followed in real time by ultraviolet-visible spectroscopy and SERS, can be controlled to yield high reproducibility on both the nanometer and the centimeter scales. On conducting substrates, colloid monolayers are electrochemically addressable and behave like a collection of closely spaced microelectrodes. These favorable properties and the ease of monolayer construction suggest a widespread use for metal colloid-based substrates. 相似文献
13.
A continuous in vitro steady-state assay procedure was used to investigate the dependence of trout brain mitochondrial Mg2+-stimulated adenosinetriphosphatase specific activity on temperature and substrate concentration. The inhibition of enzyme activity by DDT was independent of substrate concentration. DDT and several analogs caused increases in the experimental activation energy and frequency factor of the enzyme-catalyzed reaction, which gave rise to a negative temperature coefficient of inhibition. It is suggested that DDT and other highly lipophilic compounds have the potential to allosterically affect membrane-bound enzymes by simply becoming a major lipoid component of the membranes. 相似文献
14.
SR Cho SA Ock JG Yoo B Mohana kumar SY Choe GJ Rho 《Reproduction in domestic animals》2005,40(2):171-176
The present study was designed to examine the effects of cell-cycle synchronization protocols, such as confluent, roscovitine treatment and serum starvation, in bovine foetal fibroblasts on synchronization accuracy at G0/G1, viability, apoptosis, necrosis and ploidy for use as a nuclei donor. The cells in 5-10 passages were randomly allocated into three treated groups. Cells were cultured either in Dulbecco's modified Eagle's medium (DMEM) + 10% foetal bovine serum (FBS) until 90% confluent (group 1, confluent), in DMEM + 10% FBS + 30 microM roscovitine for 12 h (group 2, roscovitine), or in DMEM + 0.5% FBS for 5 days (group 3, serum starvation). Most of the cells (>80%) in all groups were arrested at the G0/G1 stage. Although the rates did not differ, cells in group 1 showed an increased cell population arrested at the G0/G1 phase. Significantly (p < 0.05) higher rates of apoptosis occurred in group 3 than in group 1 and 2 (10% vs 6% and 6%, respectively). No differences in chromosomal abnormality were observed among groups. However, by increasing the number of cell culture passages up to 15, significantly (p < 0.05) higher chromosomal abnormality was observed than in 5 and 10 passages (39% vs 28% and 23%, respectively) in group 1. The results clearly indicated that bovine foetal fibroblasts could be effectively synchronized at G0/G1 stages by all the three different treatments, confluent, roscovitine and serum starvation. However, cells in confluent showed reduced apoptosis and necrosis when they underwent 5-10 passages, exhibiting increased percentage of cells with stable chromosome diversity. Hence, cells in confluent merit further studies before they could be used as nuclear donors. 相似文献
15.
C. Bisque Jackson VMD Kenneth J. Drobatz DVM MSCE DACVIM DACVECC 《Journal of Veterinary Emergency and Critical Care》2004,14(2):115-123
Objective: To describe the clinical manifestations and treatment of hypermagnesemia and the potential drug errors that can lead to iatrogenic electrolyte toxicities. Summary: We report 2 cases of iatrogenic intravenous (IV) magnesium (Mg) overdose. Both cases developed extreme cardiovascular and neurologic symptoms consisting of vomiting, hypotension, bradycardia, flaccid paralysis, and severe mental depression. Diagnosis was made based upon serum ionized Mg levels (3.47 mmol/L; reference range: 0.43–0.58 mmol/L for Case #1; and 4.64 mmol/L; reference range: 0.42–0.55 mmol/L for Case #2). Each animal was treated with 0.9% NaCl for diuresis and IV calcium gluconate. Within 24 hours, the cardiovascular and neurologic status of both animals, as well as the serum Mg concentration, had normalized. Each animal was discharged with no complications. Both animals had been hospitalized for critical illness and had developed hypomagnesemia that was being treated with Mg sulfate infusions. The cause for the hypermagnesemia was due to miscalculations in treatment orders that led to erroneously administered Mg‐containing solutions. Confusing drug labels and varying units of measurement can lead to erroneous miscalculations, especially in critically ill patients that receive multiple IV infusions. New information provided: This is the first case report of iatrogenic Mg overdose in veterinary medicine. These 2 cases had a good clinical outcome with prompt recognition and supportive care. 相似文献
16.
Effects of hyperbaric oxygen therapy on uncomplicated incisional and open wound healing in dogs 下载免费PDF全文
17.
Laryngeal mask airway and transient hypercapnic hyperpnea for video‐endoscopic assessment of unilateral laryngeal paralysis in dogs 下载免费PDF全文
18.
19.
Removal of hemangiosarcoma cells from canine blood with a cell salvage system and leukocyte reduction filter 下载免费PDF全文
20.