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991.
K.J. Lang MS B.D. Nielsen PhD K.L. Waite MS G.A. Hill PhD M.W. Orth PhD 《Journal of Equine Veterinary Science》2001,21(11)
This study examined the effect of supplementation of a bioavailable source of silicon (sodium zeolite A) on altering systemic markers of bone metabolism in horses. Twenty yearlings (ten Quarter Horses and ten Arabians) were randomly grouped as silicon (Si) supplemented (S; n=10), in which yearlings consumed 2% of the total diet as a Si-containing supplement, and a second non-supplemented control group (C; n=10). Blood samples were taken on days 0, 15, 30 and 45. Both plasma and serum were collected; the plasma was analyzed for Si concentrations and serum was analyzed for osteocalcin (OC), carboxy-terminal pyridinoline cross-linked telopeptide region of type I collagen (ICTP), and pyridinoline and deoxypyridinoline crosslinks (PYD). Supplemented yearlings had higher plasma Si concentrations than C yearlings by day 15, and remained higher than C yearlings on days 30 and 45 (P < 0.0001 for all days). There were no differences between treatment groups for OC or PYD concentrations (P > .05); however, ICTP concentrations were lower in S yearlings on day 45 when compared to C yearlings (P = .04). Results indicate that sodium zeolite A supplementation (consumed at 2% of the total diet) increases plasma Si concentrations. Furthermore, results indicate that Si-supplemented yearlings may have decreased bone resorption, which may provide for greater net bone formations, as OC concentrations were not different between groups. Unfortunately, systemic markers give no indication as to the quality of the bone that may be formed, and further research in the area of Si supplementation, bone metabolism and bone strength is required to establish conclusive evidence as to the benefits of supplemental Si to the skeletal system. 相似文献
992.
993.
W Yi PM Clark DE Mason MC Keenan C Hill WA Goddard EC Peters EM Driggers LC Hsieh-Wilson 《Science (New York, N.Y.)》2012,337(6097):975-980
Cancer cells must satisfy the metabolic demands of rapid cell growth within a continually changing microenvironment. We demonstrated that the dynamic posttranslational modification of proteins by O-linked β-N-acetylglucosamine (O-GlcNAcylation) is a key metabolic regulator of glucose metabolism. O-GlcNAcylation was induced at serine 529 of phosphofructokinase 1 (PFK1) in response to hypoxia. Glycosylation inhibited PFK1 activity and redirected glucose flux through the pentose phosphate pathway, thereby conferring a selective growth advantage on cancer cells. Blocking glycosylation of PFK1 at serine 529 reduced cancer cell proliferation in vitro and impaired tumor formation in vivo. These studies reveal a previously uncharacterized mechanism for the regulation of metabolic pathways in cancer and a possible target for therapeutic intervention. 相似文献
994.
B Button LH Cai C Ehre M Kesimer DB Hill JK Sheehan RC Boucher M Rubinstein 《Science (New York, N.Y.)》2012,337(6097):937-941
Mucus clearance is the primary defense mechanism that protects airways from inhaled infectious and toxic agents. In the current gel-on-liquid mucus clearance model, a mucus gel is propelled on top of a "watery" periciliary layer surrounding the cilia. However, this model fails to explain the formation of a distinct mucus layer in health or why mucus clearance fails in disease. We propose a gel-on-brush model in which the periciliary layer is occupied by membrane-spanning mucins and mucopolysaccharides densely tethered to the airway surface. This brush prevents mucus penetration into the periciliary space and causes mucus to form a distinct layer. The relative osmotic moduli of the mucus and periciliary brush layers explain both the stability of mucus clearance in health and its failure in airway disease. 相似文献
995.
Responses of species to climate change are extremely variable, perhaps because of climate-related changes to interactions among species. We show that temperature-related changes in the dependence of the butterfly Aricia agestis on different larval host plants have facilitated rapid range expansion. Historically, the butterfly was largely restricted to a single plant species, Helianthemum nummularium, but recent warmer conditions have enabled the butterfly to increasingly use the more widespread plant species Geranium molle. This has resulted in a substantial increase in available habitat and rapid range expansion by the butterfly (79 kilometers northward in Britain in 20 years). Interactions among species are often seen as constraints on species' responses to climate change, but we show that temperature-dependent changes to interspecific interactions can also facilitate change. 相似文献
996.
Bonnie Chaban Shirley Chu Steven Hendrick Cheryl Waldner Janet E. Hill 《Canadian journal of veterinary research》2012,76(3):166-173
The detection and subspeciation of Campylobacter fetus subsp. venerealis (CFV) from veterinary samples is important for both clinical and economic reasons. Campylobacter fetus subsp. venerealis is the causative agent of bovine genital campylobacteriosis, a venereal disease that can lead to serious reproductive problems in cattle, and strict international regulations require animals and animal products to be CFV-free for trade. This study evaluated methods reported in the literature for CFV detection and reports the translation of an extensively tested CFV-specific polymerase chain reaction (PCR) primer set; including the VenSF/VenSR primers and a real-time, quantitative PCR (qPCR) platform using SYBR Green chemistry. Three methods of preputial sample preparation for direct qPCR were evaluated and a heat lysis DNA extraction method was shown to allow for CFV detection at the level of approximately one cell equivalent per reaction (or 1.0 × 103 CFU/mL) from prepuce. The optimized sample preparation and qPCR protocols were then used to evaluate 3 western Canadian bull cohorts, which included 377 bulls, for CFV. The qPCR assay detected 11 positive bulls for the CFV-specific parA gene target. DNA sequence data confirmed the identity of the amplified product and revealed that positive samples were comprised of 2 sequence types; one identical to previously reported CFV parA gene sequences and one with a 9% sequence divergence. These results add valuable information towards our understanding of an important CFV subspeciation target and offer a significantly improved format for an internationally recognized PCR test. 相似文献
997.
KK Thakur GR Pant L Wang CA Hill RM Pogranichniy S Manandhar AJ Johnson 《Zoonoses and public health》2012,59(6):393-400
Japanese encephalitis was recently reported from individuals in the mountain districts of Nepal without travel history to Japanese encephalitis virus (JEV) endemic areas. We performed a cross-sectional study to estimate the seroprevalence of JEV in pigs and subsequently conducted a survey of farmers to identify risk factors associated with seropositivity. In July and August, 2010, 454 pig serum samples were collected and tested by competitive ELISA. Data from a 35-question survey of 109 pig owners were analysed using multivariate logistic regression. Seventy-six (16.7, 95% CI 13.6-20.4) pigs tested positive for anti-JEV antibodies, none of which had been vaccinated against JEV or sourced from JEV endemic areas. Risk factors associated with JEV seropositivity were 'summer abortion', 'wells as a water source', 'urban location', 'reported presence of mosquitoes' and 'lower elevation'. Our results suggest that JEV is likely circulating in the mountain districts of Nepal, and that locally acquired JEV should be considered a risk for residents and travellers in these areas. 相似文献
998.
Current methods for vector‐borne disease surveillance are limited by time and cost. To avoid human infections from emerging zoonotic diseases, it is important that the United States develop cost‐effective surveillance systems for these diseases. This study examines the methodology used in the surveillance of a plague epizootic involving tree squirrels (Sciurus niger) in Denver Colorado, during the summer of 2007. A call‐in centre for the public to report dead squirrels was used to direct animal carcass sampling. Staff used these reports to collect squirrel carcasses for the analysis of Yersinia pestis infection. This sampling protocol was analysed at the census tract level using Poisson regression to determine the relationship between higher call volumes in a census tract and the risk of a carcass in that tract testing positive for plague. Over‐sampling owing to call volume‐directed collection was accounted for by including the number of animals collected as the denominator in the model. The risk of finding an additional plague‐positive animal increased as the call volume per census tract increased. The risk in the census tracts with >3 calls a month was significantly higher than that with three or less calls in a month. For tracts with 4–5 calls, the relative risk (RR) of an additional plague‐positive carcass was 10.08 (95% CI 5.46–18.61); for tracts with 6–8 calls, the RR = 5.20 (2.93–9.20); for tracts with 9–11 calls, the RR = 12.80 (5.85–28.03) and tracts with >11 calls had RR = 35.41 (18.60–67.40). Overall, the call‐in centre directed sampling increased the probability of locating plague‐infected carcasses in the known Denver epizootic. Further studies are needed to determine the effectiveness of this methodology at monitoring large‐scale zoonotic disease occurrence in the absence of a recognized epizootic. 相似文献
999.
Murray R. Woodbury Shelagh Copeland Brent Wagner Champika Fernando Janet E. Hill Cathy Clemence 《The Canadian veterinary journal. La revue veterinaire canadienne》2012,53(7):791-794
The discovery of the parasite Toxocara vitulorum in bison calves in the province of Manitoba, Canada is discussed. This parasite is more commonly found in the small intestines of bovid calves living in tropical and subtropical regions of the world. This is the first time that Toxocara vitulorum has been reported from hosts in Canada. 相似文献
1000.