全文获取类型
收费全文 | 1116篇 |
免费 | 40篇 |
国内免费 | 3篇 |
专业分类
林业 | 112篇 |
农学 | 18篇 |
基础科学 | 12篇 |
258篇 | |
综合类 | 124篇 |
农作物 | 109篇 |
水产渔业 | 34篇 |
畜牧兽医 | 361篇 |
园艺 | 28篇 |
植物保护 | 103篇 |
出版年
2022年 | 12篇 |
2021年 | 11篇 |
2020年 | 17篇 |
2019年 | 20篇 |
2018年 | 26篇 |
2017年 | 18篇 |
2016年 | 29篇 |
2015年 | 17篇 |
2014年 | 28篇 |
2013年 | 52篇 |
2012年 | 48篇 |
2011年 | 56篇 |
2010年 | 29篇 |
2009年 | 38篇 |
2008年 | 44篇 |
2007年 | 49篇 |
2006年 | 59篇 |
2005年 | 69篇 |
2004年 | 43篇 |
2003年 | 53篇 |
2002年 | 47篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 13篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 18篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 11篇 |
1972年 | 7篇 |
1971年 | 8篇 |
1952年 | 6篇 |
1926年 | 11篇 |
1925年 | 10篇 |
1924年 | 7篇 |
排序方式: 共有1159条查询结果,搜索用时 921 毫秒
141.
142.
Grünberg W Morin DE Drackley JK Barger AM Constable PD 《Journal of the American Veterinary Medical Association》2006,229(3):413-420
OBJECTIVE: To determine the effect of continuous IV administration of 50% dextrose solution on phosphorus homeostasis in lactating dairy cows. DESIGN: Clinical trial. ANIMALS: 4 multiparous Jersey cows. PROCEDURES: Cows were administered 50% dextrose solution IV (0.3 g/kg/h [0.14 g/lb/h]) for 5 days. Plasma concentrations of glucose, immune-reactive insulin (IRI), and phosphorus were determined before, during, and for 72 hours after dextrose infusion. Phosphorus intake and losses of phosphorus in urine, feces, and milk were determined. Each cow received a sham treatment that included instrumentation and sampling but not administration of dextrose. RESULTS: Plasma glucose, IRI, and phosphorus concentrations were stable during sham treatment. Plasma phosphorus concentration decreased rapidly after onset of dextrose infusion, reaching a nadir in 24 hours and remaining less than baseline value for 36 hours. Plasma phosphorus concentration increased after dextrose infusion was stopped, peaking in 6 hours. Urinary phosphorus excretion did not change during dextrose infusion, but phosphorus intake decreased because of reduced feed intake, followed by decreased fecal phosphorus loss and milk yield. Rapid changes in plasma phosphorus concentration at the start and end of dextrose infusion were temporally associated with changes in plasma glucose and IRI concentrations and most likely caused by compartmental shifts of phosphorus. CONCLUSIONS AND CLINICAL RELEVANCE: Hypophosphatemia developed in response to hyperglycemia or hyperinsulinemia in dairy cows administered dextrose via continuous IV infusion. Veterinarians should monitor plasma phosphorus concentration when administering dextrose in this manner, particularly in cows with decreased appetite or preexisting hypophosphatemia. 相似文献
143.
MacArthur DG Balasubramanian S Frankish A Huang N Morris J Walter K Jostins L Habegger L Pickrell JK Montgomery SB Albers CA Zhang ZD Conrad DF Lunter G Zheng H Ayub Q DePristo MA Banks E Hu M Handsaker RE Rosenfeld JA Fromer M Jin M Mu XJ Khurana E Ye K Kay M Saunders GI Suner MM Hunt T Barnes IH Amid C Carvalho-Silva DR Bignell AH Snow C Yngvadottir B Bumpstead S Cooper DN Xue Y Romero IG; Genomes Project Consortium Wang J Li Y Gibbs RA McCarroll SA Dermitzakis ET Pritchard JK Barrett JC 《Science (New York, N.Y.)》2012,335(6070):823-828
Genome-sequencing studies indicate that all humans carry many genetic variants predicted to cause loss of function (LoF) of protein-coding genes, suggesting unexpected redundancy in the human genome. Here we apply stringent filters to 2951 putative LoF variants obtained from 185 human genomes to determine their true prevalence and properties. We estimate that human genomes typically contain ~100 genuine LoF variants with ~20 genes completely inactivated. We identify rare and likely deleterious LoF alleles, including 26 known and 21 predicted severe disease-causing variants, as well as common LoF variants in nonessential genes. We describe functional and evolutionary differences between LoF-tolerant and recessive disease genes and a method for using these differences to prioritize candidate genes found in clinical sequencing studies. 相似文献
144.
Leptospirosis as the most frequent infectious disease impairing productivity in small ruminants in Rio de Janeiro,Brazil 总被引:2,自引:2,他引:0
Martins G Penna B Hamond C Leite RC Silva A Ferreira A Brandão F Oliveira F Lilenbaum W 《Tropical animal health and production》2012,44(4):773-777
Despite the importance of small ruminants breeding in developing countries, milk/meat productivity remains unsatisfactory.
Infectious diseases, such as leptospirosis, brucellosis, and small ruminant lentiviruses (SRLVs), contribute to this scenario.
The objective of the present study was to determine the role of each of these diseases in the productivity of small ruminants
breeding in Rio de Janeiro, Brazil. In goats, 343 samples were tested for leptospirosis, 560 for Brucella abortus, and 506 for caprine arthritis-encephalitis (CAE), whereas in sheep, 308 samples were tested for leptospirosis, 319 for B. abortus, 374 for Brucella ovis, and 278 for Maedi-Visna (MV). Regarding leptospirosis, 25.9% of goats and 47.4% sheep were seroreactive, with serovar Hardjo
the most prevalent in both species. Anti-B. abortus agglutinins were found in 0.7% of all samples, exclusively in goats. In relation to SRLVs, 8.6% of goats and 3.2% of sheep
samples were positive for CAE and MV, respectively. Leptospirosis was the major infectious problem in the small ruminants
sampled and may contribute to impaired productivity of these animals. 相似文献
145.
146.
147.
Background – Staphylococcus pseudintermedius is an important canine pathogen, and the emergence and widespread dissemination of meticillin‐resistant strains (MRSP) is of significant concern. Multidrug‐resistant infections may require alternative approaches, such as the use of topical therapy. There is minimal information about the in vitro susceptibility of meticillin‐susceptible S. pseudintermedius (MSSP) and MRSP to biocides and topical antimicrobials. Hypothesis/Objectives – The hypothesis was that clinical isolates of MSSP and MRSP would not have universal susceptibility to topical biocides and antimicrobials. The goal of this study was to assess the susceptibility of a collection of S. pseudintermedius isolates to selected antimicrobials and biocides. Animals – The study was performed on clinical isolates of MSSP and MRSP from dogs with skin and soft tissue infections collected throughout North America between 2006 and 2008. Methods – The minimal inhibitory concentrations (MICs) of chlorhexidine digluconate, benzalkonium chloride, triclosan, accelerated hydrogen peroxide, geranium oil, tea tree oil and grapefruit seed extract were tested for 25 MRSP and 25 MSSP isolates from dogs using the agar dilution method. The MICs of fusidic acid, bacitracin and mupirocin were determined using Etests. Results – Triclosan demonstrated excellent activity against all bacterial isolates, with no growth at the lowest concentration evaluated (MIC ≤ 0.5 μg/mL). Conversely, grapefruit seed extract did not inhibit growth at the highest concentration tested (MIC > 3.84 μg/mL). All isolates were susceptible to mupirocin, fusidic acid and bacitracin. There were no significant differences noted in the range, MIC50 or MIC90 between MSSP and MRSP isolates. Conclusions and clinical importance – While isolates were susceptible to most of the tested compounds, universal susceptibility to all compounds with potential antimicrobial activity cannot be assumed, and specific testing is required. 相似文献
148.
149.
Vicente VA Orélis-Ribeiro R Najafzadeh MJ Sun J Guerra RS Miesch S Ostrensky A Meis JF Klaassen CH de Hoog GS Boeger WA 《Veterinary microbiology》2012,158(1-2):109-122
Lethargic Crab Disease (LCD) caused extensive epizootic mortality of the mangrove land crab Ucides cordatus (Brachyura: Ocypodidae) along the Brazilian coast, mainly in the Northeastern region. The disease was named after the symptoms of slow movement of infected crabs. Causative agents were suspected to be two black yeast-like fungi of the family Herpotrichiellaceae (ascomycete order Chaetothyriales), judged by infected tissue biopsies from moribund U. cordatus. The aim of the present study is to prove that two species are involved in the disease: the recently described black yeast Exophiala cancerae, but also a less virulent, hitherto undescribed fonsecaea-like species, introduced here as the novel species Fonsecaea brasiliensis. Strains were identified by ITS rDNA sequencing, and species borderlines were established by multilocus sequencing and AFLP analysis. Fonsecaea brasiliensis proved to be closely related to the pathogenic species Cladophialophora devriesii which originally was isolated from a systemic infection in a human patient. The virulence of F. brasiliensis is lower than that of E. cancerae, as established by artificial inoculation of mangrove crabs. 相似文献
150.
Delling U Lindner K Ribitsch I Jülke H Brehm W 《Canadian journal of veterinary research》2012,76(1):52-56
The objective of this study was to compare bone marrow (BM) aspirates from the sternum and the tuber coxae of middle-aged horses. Bone marrow was obtained from the sternum and both tubera coxae of 12 healthy, 13-year-old geldings. Two different puncture techniques were used for the tuber coxae. The 2 syringes used for sternal sampling were evaluated separately. The mononuclear cell (MNC) fraction of the BM was isolated and the mesenchymal stem cells (MSCs) were culture-expanded. At the sternum, BM aspiration was always possible. Bone marrow aspiration at the tuber coxae required straight and deep needle penetration combined with high negative pressure. With this technique a median sample amount of 11.0 mL with large individual variation was obtained. A median of 3.06 × 10(6) MNC/mL BM (1st syringe) and 2.46 × 10(6) MNC/mL BM (2nd syringe) was isolated from sternal samples. In contrast, the tuber coxae yielded a median of 0.27 × 10(6) MNC/mL BM. The first passage yielded a median of 2.19 × 10(6) MSC (1st syringe) and 1.13 × 10(6) MSC (2nd syringe) from sternal samples, compared to a significantly lower median number of MSC from tuber coxae BM (0.06 × 10(6) MSC). The number of MNC and MSC obtainable from the BM aspirates taken from the tuber coxae is significantly lower than that obtained from the sternal BM aspirates. Autologous BM for the equine athlete is particularly clinically relevant at an advanced age. Based on our findings, the tuber coxae cannot be recommended for BM aspiration in middle-aged horses. 相似文献