全文获取类型
收费全文 | 441篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
林业 | 10篇 |
农学 | 12篇 |
基础科学 | 4篇 |
75篇 | |
综合类 | 33篇 |
农作物 | 13篇 |
水产渔业 | 35篇 |
畜牧兽医 | 265篇 |
园艺 | 7篇 |
植物保护 | 28篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 27篇 |
2013年 | 37篇 |
2012年 | 25篇 |
2011年 | 40篇 |
2010年 | 17篇 |
2009年 | 14篇 |
2008年 | 22篇 |
2007年 | 18篇 |
2006年 | 23篇 |
2005年 | 21篇 |
2004年 | 19篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 7篇 |
2000年 | 12篇 |
1999年 | 15篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1980年 | 2篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有482条查询结果,搜索用时 15 毫秒
451.
Martinez I Mattoon JS Eaton KA Chew DJ DiBartola SP 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(4):499-509
Polypoid cystitis is a rare disease of the urinary bladder in dogs characterized by inflammation, epithelial proliferation, and development of a polypoid mass or masses without histopathologic evidence of neoplasia. Medical records of 17 dogs with polypoid cystitis were reviewed to determine the clinical and laboratory features of this disorder and to assess treatment and outcome. Most affected dogs (15/17) were female and presented for evaluation of hematuria or recurrent urinary tract infection (UTI). Proteus spp were the most common bacterial isolates (12/52 or 23.1%) identified when all urine samples obtained for culture at any time during the course study were considered. Other commonly isolated organisms included Escherichia coli , Staphylococcus spp, and Enterococcus spp. Several dogs (7/17) also had cystic calculi at some time during the course of their disease. Most of the masses (11/14) were located cranioventrally in the bladder as opposed to transitional cell carcinoma, which has a predilection for the bladder neck or trigone area. It is unknown whether persistent or recurrent UTI predisposes to polyp formation or if polyps predispose to UTI. Surgery and removal of all polyps was the most efficacious treatment in dogs of this study. The question of whether or not polyps represent preneoplastic lesions remains unanswered and constitutes an area for future investigation. 相似文献
452.
Martinez Diaz MA Mori T Nagano M Katagiri S Takahashi Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(9):989-994
The effect of fusion/activation protocol on in vitro development of porcine nuclear transfer (NT) embryos constructed with foreign gene-transfected somatic cells were investigated. NT embryos were produced by using enucleated M II oocytes and enhanced green fluorescence protein (EGFP) gene-transfected or non-transfected porcine fetal fibroblasts. One group of NT embryos received a single electrical pulse to induce fusion and activation simultaneously (FAS). The other group was fused 2 hr before activation (FBA) using two kinds of electrical pulses. Electrically activated NT embryos in both groups were treated with cycloheximide (CHX) before culture to assess the development to the blastocyst stage. After 6 days of culture, all morulae and blastocysts derived from EGFP-transfected fibroblasts emitted green fluorescence without mosaicism, and EGFP-gene product was also detected in all morulae and blastocysts examined. NT embryos undergoing FAS showed higher developmental capacity to blastocysts than those undergoing FBA, regardless of the EGFP transfection into the nuclear donor cells. The results also indicated that EGFP-gene transfection into nuclear donor cells has no obvious deleterious effect on the development of NT embryos to blastocysts. 相似文献
453.
The objective of this experiment was to compare two progestins and three treatments for synchronizing follicular wave emergence and ovulation in protocols for fixed-time AI in beef heifers. On d 0 (beginning of the experiment), Angus and Angus-Simmental cross beef heifers at random stages of the estrous cycle either received a CIDR-B device (n = 257) or were started on 0.5 mg x anima(-1) x d(-1) melengestrol acetate (MGA; n = 246) and were randomly assigned to receive i.m. injections of 100 microg GnRH, 12.5 mg porcine LH (pLH), or 2 mg estradiol benzoate (EB) and 50 mg progesterone (P4). The last feeding of MGA was given on d 6 and on d 7, CIDR-B devices were removed and all heifers received 500 microg cloprostenol (PG). Consistent with their treatment groups on d 0, heifers were given either 100 microg GnRH or 12.5 mg pLH 48 h after PG (and were concurrently inseminated) or 1 mg EB 24 h after PG and were inseminated 28 h later (52 h after PGF). Estrus rate (combined for both progestins) in heifers receiving EB (92.0%) was greater (P < 0.05) than that in heifers receiving GnRH and pLH (combined) and a CIDR-B device (62.9%) or MGA (34.3%). Although the mean interval from PG treatment to estrus did not differ among groups (overall, 47.8 h; P = 0.85), it was less variable (P < 0.01) in MGA-fed heifers (SD = 2.5 h) than in CIDR-B-treated heifers (SD = 8.1 h). Pregnancy rates (determined by ultrasonography approximately 30 d after AI) did not differ (P = 0.30) among the six treatment groups (average, 58.0%; range, 52.5 to 65.0%). Although fixed-time AI was done, pregnancy rates were greater in heifers detected in estrus than in those not detected in estrus (62.6 vs 51.9%; P < 0.05). In conclusion, GnRH, pLH, or EB treatment in combination with a CIDR-B device or MGA effectively synchronized ovulation-for fixed-time AI, resulting in acceptable pregnancy rates in beef heifers. 相似文献
454.
455.
EA Martinez JM Vazquez J Roca C Cuello MA Gil I Parrilla JL Vazquez 《Reproduction in domestic animals》2005,40(4):300-309
Over the past decade, there has been an increase in the development and/or in the improvement of emerging reproductive technologies in pigs. Among emerging reproductive technologies with potential short-term application in pig production are: artificial insemination with low number of spermatozoa, cryopreservation of spermatozoa and embryos, sperm sexing, and non-surgical embryo transfer. The following review will give emphasis to recent advancements in these reproductive technologies that are starting to show possibilities of serious applications under field conditions. 相似文献
456.
WMC Maxwell I Parrilla I Caballero E Garcia J Roca EA Martinez JM Vazquez D Rath 《Reproduction in domestic animals》2007,42(5):489-494
The main aim of this study was to compare the motility and functional integrity of bull spermatozoa after single and double freezing and thawing. The viability and morphological integrity of spermatozoa selected by PureSperm density gradient centrifugation after cryopreservation of bovine semen in two commercial extenders (Experiment 1) and the function of bull spermatozoa before and after a second freezing and thawing assisted by PureSperm selection (Experiment 2) were examined. On average, 35.8 +/- 12.1% of sperm loaded onto the PureSperm density gradient were recovered after centrifugation. In Experiment 1, post-thaw motility and acrosome integrity were higher for spermatozoa frozen in Tris-egg yolk extender than in AndroMed, whether the assessments were made immediately after thawing [80.4 +/- 12.7 vs 47.6 +/- 19.0% motile and 78.8 +/- 8.3 vs 50.1 +/- 19.5% normal apical ridge (NAR), p < 0.05] or after preparation on the gradient (83.3 +/- 8.6 vs 69.4 +/- 15.9% motile and 89.5 +/- 7.2 vs 69.1 +/- 11.4% NAR, p < 0.05). For semen frozen in Tris-egg yolk extender, selection on the PureSperm gradient did not influence total motility but significantly improved the proportion of acrosome-intact spermatozoa. After the gradient, both the total motility and percentage of normal acrosomes increased for spermatozoa frozen in AndroMed (Minitüb Tiefenbach, Germany). In Experiment 2, there was no difference in sperm motility after the first and second freeze-thawing (82.9 +/- 12.7 vs 68.8 +/- 18.7%). However, the proportion of acrosome-intact spermatozoa was significantly improved by selection through the PureSperm gradient, whether measured by phase contrast microscopy (78.9 +/- 9.7 vs 90.4 +/- 4.0% NAR, p < 0.05) or flow cytometry (53.4 +/- 11.7 vs 76.3 +/- 6.0% viable acrosome-intact spermatozoa, p < 0.001). The improvement in the percentage of spermatozoa with normal acrosomes was maintained after resuspension in the cooling extender and cooling to 4 degrees C (88.2 +/- 6.2) and after re-freezing and thawing (83.6 +/- 6.56% NAR). However, flow cytometric assessment of the sperm membranes revealed a decline in the percentage of viable spermatozoa with intact membranes after the second freezing and thawing compared with after gradient centrifugation (76.3 +/- 6.0% vs 46.6 +/- 6.6%, p < 0.001) to levels equivalent to those obtained after the first round of freeze-thawing (53.4 +/- 11.7% viable acrosome-intact spermatozoa). Sperm movement characteristics assessed by computer-assisted analysis were unaffected in the population selected on the PureSperm gradients but declined after cooling of the selected and extended spermatozoa to 4 degrees C. There was no further change in these kinematic measurements after the cooled spermatozoa had undergone the second round of freeze-thawing. These results demonstrate that bull semen can be frozen and thawed, followed by a second freeze-thawing cycle of a population of spermatozoa selected by PureSperm, with retained motility and functional integrity. This points to the possibility of using double frozen spermatozoa in bovine artificial insemination programmes and to the potential benefits of PureSperm density gradient centrifugation for the application of cryopreserved bull spermatozoa to other biotechnological procedures such as flow cytometric sex sorting followed by re-freezing and thawing. 相似文献
457.
Ashley B. Saunders DVM Dipl. ACVIM Elizabeth A. Martinez DVM Dipl. ACVA Matthew W. Miller DVM MS Dipl. ACVIM 《Journal of Veterinary Cardiology》2007,9(2):119-122
Catheters and pacing leads may become entrapped within the heart necessitating the use of creative measures for extraction while preventing damage to cardiac structures. This report describes the percutaneous extraction of a knotted pulmonary artery catheter and an entrapped tined pacing lead in two dogs. In both cases, a long transseptal sheath was advanced over the catheter or pacing lead and used to facilitate removal of the entrapped devices without causing damage to the heart. 相似文献
458.
Ingrid van Hoek Hannah Hodgkiss-Geere Elizabeth F. Bode Julie Hamilton-Elliott Paul Mõtsküla Valentina Palermo Yolanda Martinez Pereira Geoff J. Culshaw Jeremy Laxalde Joanna Dukes-McEwan 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(6):2197-2210
459.
Manuel Alvarez-Rodriguez Maria Ntzouni Dominic Wright Kabirul Islam Khan Manel López-Béjar Cristina A. Martinez Heriberto Rodriguez-Martinez 《Reproduction in domestic animals》2020,55(3):293-300
The avian seminal fluid (SF) is a protein-rich fluid, derived from the testis, the rudimentary epididymis and, finally, from the cloacal gland. The SF interacts with spermatozoa and the inner cell lining of the female genital tract, to modulate sperm functions and female immune responsiveness. Its complex proteome might either be free or linked to extracellular vesicles (EVs) as it is the case in mammals, where EVs depict the tetraspanin CD9; and where those EVs derived from the epididymis (epididymosomes) also present the receptor CD44. In the present study, sperm-free SF from Red Jungle Fowl, White Leghorn and an advanced intercross (AIL, 12th generation) were studied using flow cytometry of the membrane marker tetraspanin CD9, Western blotting of the membrane receptor CD44 and electron microscopy in non-enriched (whole SF) or enriched fractions obtained by precipitation using a commercial kit (Total Exosome Precipitation Solution). Neither CD9- nor CD44 could be detected, and the ultrastructure confirmed the relative absence of EVs, raising the possibility that avian SF interacts differently with the female genitalia as compared to the seminal plasma of mammals. 相似文献
460.
Herminia Emilia Prieto Martinez Paulo Roberto Cecon 《Journal of plant nutrition》2015,38(7):1073-1082
In Brazil there are two usual forms of supplying zinc (Zn) to coffee plants, in the soil with macronutrient fertilizers or by means of foliar sprayings. Both have limitations that compromise the Zn availability to the plant. This study examined the plant responses to the foliar sprays with ZnSO4 and insertion of Zn salt tablets, made with a mix of Zn sources, into the orthotropic branches of Coffea arabica L. Zinc supplied by foliar sprays or tablets inserted into the trunk both increased leaf Zn content, although the tablets provided more consistent Zn supply. Coffee production was higher with Zn treatments, regardless of the method of supply. The supply of Zn by the insertion of tablets into coffee tree trunks thus proved to be a promising way to supply Zn. 相似文献