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111.
Ammonia in cigarette mainstream smoke was quantified by LC-MS/MS after derivatization. Two different reagents, fluorescamine and dansyl chloride, were investigated, but only the latter gave stable derivatives; therefore, it was considered the most appropriate choice. Smoke samples were collected on a Cambridge filter pad followed by an impinger containing a solution of hydrochloric acid. Ammonia was then derivatized with a 18.5 mM solution of dansyl chloride in acetonitrile at 70 °C for 30 min in a vial with the internal standard, (15)ND(4)Cl. The resulting derivative was analyzed by LC-MS/MS detection with an atmospheric pressure chemical ionization (APCI) interface in the positive ionization mode using multiple-reaction monitoring (MRM). Good linearity was obtained in the concentration range of 0.02-1.65 μg/mL (r(2) ≥ 0.999), and the limit of detection (LOD) was established at 0.006 μg/mL. This method has the advantage of being sensitive, efficient, and reliable and is not hindered by interferences from the sample matrix. It should thus be considered a reference method of choice for the determination of ammonia in smoke. 相似文献
112.
113.
Wefel S Mendez-Angulo JL Ernst NS 《The Canadian veterinary journal. La revue veterinaire canadienne》2011,52(8):884-887
A 4-year-old Quarter horse stallion was presented for acute abdominal pain. Exploratory celiotomy revealed a mesenteric diverticulum of the jejunum and mesodiverticular band that were associated with small intestinal strangulation. Resection and anastomosis were performed. A second celiotomy was performed due to adhesions. The horse recovered completely and returned to training. 相似文献
114.
Crépin S Chekabab SM Le Bihan G Bertrand N Dozois CM Harel J 《Veterinary microbiology》2011,153(1-2):82-88
During the course of infection, bacteria must coordinately regulate gene expression in response to environmental stimuli. The phosphate (Pho) regulon is controlled by the two component-regulatory system PhoBR. PhoBR is activated during starvation and regulates genes involved in phosphate homeostasis. Several studies have highlighted the importance of the Pho regulon in bacterial pathogenesis, showing how induction of PhoBR, in addition to regulating genes participating in phosphate metabolism, leads to modulation of many cellular processes. The pleiotropic effects of Pho regulon activation include attenuated virulence and alteration of many virulence traits, including adhesion to host cells and resistance to cationic antimicrobial peptides, acidity and oxidative stresses. This review provides an overview of the relationship between the Pho regulon and virulence in Escherichia coli and illustrates that, in addition to regulating phosphate homeostasis, the Pho regulon plays a key role in regulating stress responses and virulence. 相似文献
115.
Kim CY Bordenave N Ferruzzi MG Safavy A Kim KH 《Journal of agricultural and food chemistry》2011,59(3):1012-1019
Conjugation of curcumin (CCM) by polyethylene glycol (PEG) has been previously developed to improve water solubility of the natural form of CCM and its antiproliferative role in some human cancer cell lines. This study examined the cellular uptake kinetics of the natural form of CCM and CCM-PEG. Their cytotoxic effect in proliferating preadipocytes and antiadipogenic property in differentiating preadipocytes had also been investigated. CCM and CCM-PEG were found to be differently absorbed in 3T3-L1 preadipocytes and adipocytes with a limited amount of CCM-PEG absorption in the cell. The improved water solubility of CCM-PEG was correlated with increased cellular retention of CCM in 3T3-L1 cells, particularly in preadipocytes. Consequently, CCM-PEG treatment sensitized proliferating preadipocytes to CCM-induced cell toxicity. Furthermore, incubation of differentiating 3T3-L1 cells with CCM-PEG resulted in improvement of the inhibitory role of CCM in adipocyte differentiation with no toxic effect. These results suggest that pegylation-improved water solubility and cellular retention of CCM may be uniquely useful for improving the delivery of CCM in preadipocytes and its antiadipogenic ability. 相似文献
116.
Robles Jimenez Lizbeth E. Ruiz Perez Jose A. Nicolas Di Lorenzo Chay Canul Alfonso J. Ramirez-Rivera Julio Cesar Villegas-Estrada Daniela Vargas-Bello-Pérez Einar Gonzalez-Ronquillo Manuel 《Tropical animal health and production》2020,52(3):1257-1267
Tropical Animal Health and Production - Currently for the reduction of methane (CH4) emissions are using fodder rich in condensed tannins, however, not yet known exactly how they act in the rumen... 相似文献
117.
Gregoria Pulgar Gemma Víllora Joaquin Hernández Nicolas Castilla Luis Romero 《Journal of plant nutrition》2013,36(6):719-730
Chinese cabbage plants [Brassica pekinensis (Lour) Rupr. cv. Nagaoka 50] were cultivated experimentally for two years (1993 and 1994) using a semi‐forcing technique of floating rowcovers, polyethylene (T1), polypropylene (T2), versus no floating row‐covers, control (T0). Five samplings were made, taking four plants per each replication and total phosphorus (P) (Ptotal), inorganic P (Pi), and calculated organic P (Porg) were determined as well as foliar acid phosphatase activity (FAPA). The aerial and root temperatures of the treatments T1 and T2 exceeded those of T0. The Ptotal concentration showed no significant variations with treatment, whereas the Pi concentrations increased in Ti and T2 and Porg decreased in both treatments with respect to T0. The FAPA was influenced a similar way as Pi, raising with temperature. The contents (mg plant‐1) of Ptolal, Pi, and Porg were greater in T1 and T2 than in T0, and this could be due to the fact that the highest temperatures (root and aerial zone) generated by the plastic rowcovers favored the absorption of P, thereby boosting FAPA and the fresh and dry weights, and yield. 相似文献
118.
Petrović Andjeljko Pérez Hidalgo Nicolas Michelena Saval José Manuel Tomanović Željko 《Phytoparasitica》2021,49(1):93-101
Phytoparasitica - Here we describe Aphidius erodii sp. n. associated with Acyrthosiphon malvae (Mosley, 1841), which is a pest on herbaceous ornamental Geranium and Pelargonium plants, but also an... 相似文献
119.
Cambou Aurélie Saby Nicolas P.A. Hunault Gilles Nold François Cannavo Patrice Schwartz Christophe Vidal-Beaudet Laure 《Journal of Soils and Sediments》2021,21(2):1038-1052
Journal of Soils and Sediments - Assessments of urban soil organic carbon stock (SOCS) are scant because citywide data are scarce. Moreover, we do not know which factors mostly explain SOCS spatial... 相似文献
120.
Prediction of internal bond strength in a medium density fiberboard process using multivariate statistical methods and variable selection 总被引:2,自引:1,他引:1
Nicolas André Hyun-Woo Cho Seung Hyun Baek Myong-Kee Jeong Timothy M. Young 《Wood Science and Technology》2008,42(7):521-534
This paper presents new data mining-based multivariate calibration models for predicting internal bond strength from medium
density fiberboard (MDF) process variables. It utilizes genetic algorithms (GA) based variable selection combined with several
calibration methods. By adopting a proper variable selection scheme, the prediction performance can be improved because of
the exclusion of non-informative variable(s). A case study using real plant data showed that the calibration models based
on the process variables selected by GA produced better performance than those without variable selection, with the exception
of the radial basis function (RBF) neural networks model. In particular, the calibration model based on supervised probabilistic
principal component analysis (SPPCA) yielded better performance (only when using GA) than partial least squares (PLS), orthogonal-PLS
(O-PLS), and radial basis function neural networks models. The SPPCA model benefits most from the use of GA-based variable
selection in this case study.
N. André and H.-W. Cho equally contributed to this work. 相似文献