全文获取类型
收费全文 | 1091篇 |
免费 | 69篇 |
国内免费 | 1篇 |
专业分类
林业 | 46篇 |
农学 | 24篇 |
基础科学 | 3篇 |
223篇 | |
综合类 | 120篇 |
农作物 | 64篇 |
水产渔业 | 138篇 |
畜牧兽医 | 459篇 |
园艺 | 15篇 |
植物保护 | 69篇 |
出版年
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 24篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 16篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 41篇 |
2012年 | 39篇 |
2011年 | 49篇 |
2010年 | 29篇 |
2009年 | 21篇 |
2008年 | 68篇 |
2007年 | 63篇 |
2006年 | 87篇 |
2005年 | 71篇 |
2004年 | 75篇 |
2003年 | 83篇 |
2002年 | 73篇 |
2001年 | 8篇 |
2000年 | 14篇 |
1999年 | 16篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1973年 | 5篇 |
1953年 | 5篇 |
1948年 | 6篇 |
1947年 | 6篇 |
1946年 | 5篇 |
1945年 | 7篇 |
1942年 | 5篇 |
排序方式: 共有1161条查询结果,搜索用时 15 毫秒
991.
OBJECTIVE: A clinical trial to determine whether continuous infusion administration technique was suitable for maintaining neuromuscular blockade with rocuronium bromide in dogs. ANIMALS: Twenty-two dogs, 10 males and 12 females, median age 2 years 4 months, median weight 32 kg undergoing elective surgical procedures under general anaesthesia: ASA classification I or II. MATERIALS AND METHODS: After induction of anaesthesia, neuromuscular function was evaluated using train-of-four (TOF) stimulation of the dorsal buccal branch of the facial nerve. A bolus dose of 0.5 mg kg(-1) rocuronium was administered intravenously and an infusion of 0.2 mg kg(-1) hour(-1) was started immediately. Neuromuscular blockade was assessed visually by counting the number of twitches observed during TOF stimulation repeated at 10-second intervals. RESULTS: The bolus dose of rocuronium abolished the response to TOF stimulation in 21 of the 22 dogs. The median onset time of neuromuscular blockade (complete loss of all four twitches) was 82 seconds (range 38-184 seconds). Median infusion duration was 76 minutes (range 20.3-146 minutes). CONCLUSIONS AND CLINICAL RELEVANCE: This protocol of rocuronium administration was considered to be effective in dogs. Constant infusion of rocuronium is easily applicable to clinical practice and further work is required on infusion titration. 相似文献
992.
Anthocyanins were systematically identified and characterized by HPLC-ESI-MS/MS coupled with diode array detection in common fruits from U.S. food markets and other commercial sources. Of the 25 different fruits that were screened, 14 fruits were found to contain anthocyanins; the number of anthocyanins varied from 2 in peaches and nectarines to 31 in Concord grape. The individual anthocyanins were identified by comparing their mass spectral data and retention times with those of standards and published data. In all of the samples analyzed, only 6 common anthocyanidins, delphinidin, cyanidin, pelargonidin, petunidin, peonidin and malvidin, were found. In addition to the well-known major anthocyanins, a number of minor anthocyanins were identified for the first time. Some possible guidelines that help to identify anthocyanins in foods with complex anthocyanin composition were deduced and discussed. For the first time, this paper presents complete anthocyanin HPLC profiles and MS spectral data of common fruits using the same uniform experimental conditions. 相似文献
993.
Huang D Ou B Hampsch-Woodill M Flanagan JA Prior RL 《Journal of agricultural and food chemistry》2002,50(16):4437-4444
The oxygen radical absorbance capacity (ORAC) assay has been widely accepted as a standard tool to measure the antioxidant activity in the nutraceutical, pharmaceutical, and food industries. However, the ORAC assay has been criticized for a lack of accessibility due to the unavailability of the COBAS FARA II analyzer, an instrument discontinued by the manufacturer. In addition, the manual sample preparation is time-consuming and labor-intensive. The objective of this study was to develop a high-throughput instrument platform that can fully automate the ORAC assay procedure. The new instrument platform consists of a robotic eight-channel liquid handling system and a microplate fluorescence reader. By using the high-throughput platform, the efficiency of the assay is improved with at least a 10-fold increase in sample throughput over the current procedure. The mean of intra- and interday CVs was 相似文献
994.
Wanasundara PK Ross AR Amarowicz R Ambrose SJ Pegg RB Shand PJ 《Journal of agricultural and food chemistry》2002,50(24):6981-6988
Defibrinated bovine plasma (DBP) was treated with the microbial protease Flavourzyme to obtain protein hydrolysates with various degrees of hydrolysis (DH). The angiotensin I-converting enzyme (ACE) inhibiting activity of the hydrolyzed protein was assessed with hippuryl-His-Leu as the substrate. The amount of hippuric acid released, due to uninhibited ACE activity, was determined by high-performance liquid chromatography. ACE inhibiting (ACEI) activity was found to increase with increasing DH; the 43% DH hydrolysate exhibited the highest activity and had an IC(50) of 1.08 mg/mL. Peptide fractions with high ACEI activity were isolated using size exclusion chromatography. The fraction that possessed the highest ACEI activity contained peptides with GYP, HL(I), HPY, HPGH, L(I)F, SPY, and YPH sequence motifs, as determined by reversed-phase liquid chromatography-tandem mass spectrometry using a novel immonium precursor-ion scanning technique. Some of these motifs correspond to sequences found in bovine serum albumin, a potential source of ACEI peptides in bovine plasma. 相似文献
995.
Sequential extraction and quantitative recovery of gliadins, glutenins, and other proteins from small samples of wheat flour 总被引:6,自引:0,他引:6
Methods to sequentially extract and fractionate wheat flour proteins were evaluated to reliably quantify gliadins, glutenins, and albumins/globulins in single flour samples. Compositions of the resulting protein fractions were analyzed by RP-HPLC combined with SDS-PAGE. Unknown proteins were identified by mass spectrometry or N-terminal sequencing. The best separation and recovery of discrete albumin/globulin, gliadin, and glutenin fractions from the same flour sample was achieved by extraction with 0.3 M NaI in 7.5% 1-propanol followed by 2% SDS, 25 mM DTT in 25 mM TRIS, pH 8.0, and precipitation of the solubilized proteins with ammonium acetate/methanol followed by acetone. Average flour composition for the variety Butte86 was 10% albumin/globulin, 40% gliadin, and 48% glutenin. This method should be useful for determining flour composition in diverse samples and evaluating relationships between proteins and end-use functionality. 相似文献
996.
Samplers designed to collect bulk atmospheric fallout were located at three sites around Lake Carl Blackwell, Oklahoma in order to gather data regarding the atmospheric contribution of P to the Lake. Based on the data collected, it was determined that the atmosphere is a definite source of P to Lake Carl Blackwell. It was also concluded that P quantities, as a general trend, increased as the volume of precipitation increased and that atmospheric contributions vary with sampler location. Based on the average annual atmospheric P contribution and the average calculated surface area and lake volume, it was determined that the atmosphere can become a significant non-point source of P to this aquatic system. 相似文献
997.
Rapid fluorescence polarization immunoassay for the mycotoxin deoxynivalenol in wheat 总被引:5,自引:0,他引:5
The fungus Fusarium graminearum, a pathogen of both wheat and maize, produces a toxin, deoxynivalenol (DON), that causes disease in livestock. A rapid test for DON in wheat was developed using the principle of fluorescence polarization (FP) immunoassay. The assay was based on the competition between DON and a novel DON-fluorescein tracer (DON-FL2) for a DON-specific monoclonal antibody in solution. The method, which is a substantial improvement over our previous DON FP immunoassay, combined a rapid (3 min) extraction step with a rapid (2 min) detection step. A series of naturally contaminated wheat and maize samples were analyzed by both FP immunoassay and liquid chromatography (HPLC-UV). For wheat the HPLC-UV and FP methods agreed well (linear regression r(2) = 0.936), but for maize the two methods did not (r (2) = 0.849). We conclude that the FP method is useful for screening wheat, but not maize, for DON. 相似文献
998.
999.
1000.