首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   352篇
  免费   7篇
  国内免费   11篇
林业   9篇
农学   11篇
基础科学   2篇
  37篇
综合类   33篇
农作物   9篇
水产渔业   43篇
畜牧兽医   192篇
园艺   5篇
植物保护   29篇
  2023年   4篇
  2022年   10篇
  2021年   21篇
  2020年   3篇
  2016年   7篇
  2015年   22篇
  2014年   20篇
  2013年   14篇
  2012年   10篇
  2011年   17篇
  2010年   20篇
  2009年   23篇
  2008年   13篇
  2007年   11篇
  2006年   20篇
  2005年   6篇
  2004年   10篇
  2003年   5篇
  2002年   10篇
  2001年   2篇
  1999年   2篇
  1998年   3篇
  1997年   7篇
  1996年   6篇
  1995年   2篇
  1994年   3篇
  1993年   6篇
  1991年   2篇
  1987年   2篇
  1985年   7篇
  1984年   2篇
  1982年   4篇
  1981年   4篇
  1980年   2篇
  1979年   3篇
  1977年   2篇
  1976年   5篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1965年   3篇
  1963年   4篇
  1961年   2篇
  1959年   4篇
  1958年   5篇
  1957年   6篇
  1956年   5篇
  1955年   2篇
  1954年   5篇
  1948年   2篇
排序方式: 共有370条查询结果,搜索用时 15 毫秒
11.
A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.  相似文献   
12.
An 8‐year‐old Shih Tzu developed abdominal pain and hyperglobulinemia. A round splenic mass was noted radiographically and sonographically. The patient was evaluated by fluorodeoxyglucose positron emission tomography coupled with computed tomography (FDG‐PET/CT). There was no evidence of metastasis or bone marrow involvement on PET/CT images. The standardized uptake value (SUV) of the splenic mass was increased over the reference range (SUV=4.83). The patient was diagnosed as splenic extramedullary plasmacytoma through immunohistopathologic study. After the splenectomy, the globulin level normalized and the patient is alive without complications.  相似文献   
13.
14.
Contrast enhanced ultrasound (CEUS) is useful to evaluate tissue perfusion in the kidney. In veterinarymedicine, sedation or anesthesia may be required in uncooperative or panting patients. The aim of this studywas to evaluate and compare the normal kidney perfusion patterns in conscious and anesthetized dogs usingCEUS. Eight healthy beagles were used in this study. Scanning was performed in conscious dogs using manualrestraint (conscious group), or under general anesthesia using tiletamine-zolazepam and medetomidine (TZMgroup) or medetomidine (M group). The contrast agent (Sonovue®) was administered as an IV bolus.The peak intensity (PI), time to peak enhancement from injection (TTP0) and the time to peakenhancement from the initial rise (TTPup), upslope, downslope and area under the curve (AUC) wereanalyzed. Compared to the cortical values in the conscious group, TTP0 was significantly delayed inthe TZM group, and upslope, TTP0 and TTPup were significantly different in the M group.The AUCs in the TZM and M groups were not different from those in the conscious group. The upslope of renalmedullary perfusion was significantly decreased in the TZM and M groups. TTP0 and TTPupwere also significantly delayed in these groups. The AUC of the medulla was significantly decreased in the Mgroup. Therefore, TZM is useful as an anesthetic protocol when performing CEUS, and the obtained data mayserve as reference values in the evaluation of renal perfusion using CEUS in dogs under anesthesia.  相似文献   
15.
Controlled cross circulation (CCC) was performed in six pairs of dogs for 45 minutes with aortic cross clamping and cardioplegia. Data were collected in donor dogs at 10 minute intervals three times before, three times during, and three times after CCC and included arterial blood pressure, pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), cardiac index (CI), heart rate (HR), blood gas analysis, temperature, maximum rate of rise of left ventricular pressure dP/dt max/End diastolic volume (EDV), blood volume (BV), complete blood count (CBC) and activated clotting times (ACT). Pulse pressure (PP), systemic vascular resistance (SVR), oxygen delivery (Do2), and left ventricular cardiac work (LVCW) were calculated. Arterial blood pressure, CVP, blood gas analysis, temperature, BV, CBC, and ACT were measured in recipient dogs. During CCC, donor hemodynamic changes resembled those observed in models of acute onset arteriovenous fistulas. Insidious BV shifts can occur despite the use of occlusive roller pumps. After CCC, donor hemodynamics resembled acute blood loss, characterized by decreases in mean arterial pressure (MAP), CVP, PCWP, and CI, and increases in SVR and dP/dt max/EDV. These changes were probably caused by pump imbalance and BV shift to the recipient dog.  相似文献   
16.
Accumulating data suggest a relationship between chemerin and energy metabolism. Our group previously described gene cloning, expression analysis and the regulatory mechanism of chemerin and its own receptor in mice and cattle. The objective of the present study was to investigate the physiological effect of chemerin on endocrine changes and energy metabolism in sheep using a biologically stable chemerin analog. The chemerin analog was intravenously administrated (100 or 500 µg/head) to sheep, and plasma insulin and metabolites (glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and high‐density lipoprotein (HDL) cholesterol) were analyzed. The chemerin analog dramatically increased the insulin levels, and glucose levels were decreased. NEFA levels were slightly decreased at 20 min but then increased gradually from 60 to 180 min after analog administration. In addition, injection of the chemerin analog immediately increased triglyceride and total cholesterol but not HDL levels. These results suggested that chemerin analog regulated insulin secretion related to glucose metabolism and the release of triglycerides in sheep in vivo. This study provides new information about endocrine and metabolic changes in response to chemerin in sheep.  相似文献   
17.
Objective— To (1) report a technique for repair of feline ilial fractures using a dorsally applied bone plate and (2) compare outcome with cats treated by a lateral plate.
Study Design— Prospective study.
Animals— Cats (n=10) with iliac fractures.
Methods— Cats with ilial fractures (January 2005–December 2006) were treated by application of a dorsally applied bone plate. Immediate postoperative radiographs were compared with those taken 4–6 weeks later to assess screw loosening, screw purchase, and pelvic canal narrowing. Owners were contacted for medium-term (>3 month) follow-up. Data were compared with a report of outcome after lateral plating (LP) in 21 cats.
Results— Mean (± SD) screw purchase (89 ± 11 mm) was significantly greater ( P <.01) with a dorsal plate compared with a lateral plate (33 ± 8 mm). Significantly more screws ( P <.01) were used with a dorsal plate (median, 7) compared with a lateral plate (median, 6). Significantly less postoperative pelvic canal narrowing developed in the dorsal plating group between postoperative and 4–6-week follow-up radiography compared with the LP group (2% versus 15%, P <.01).
Conclusion— Dorsal plating of feline ilial fractures results in significantly less screw loosening and pelvic canal narrowing at 4–6 weeks after surgery compared with LP.
Clinical Relevance— Dorsal plating of feline iliac fractures may reduce complications associated with pelvic canal narrowing such as constipation and megacolon.  相似文献   
18.
Mitochondria are highly dynamic organelles that undergo constant fusion/fission as well as activities orchestrated by large dynamin-related GTPases. These dynamic mitochondrial processes influence mitochondrial morphology, size and function. Therefore, this study was conducted to evaluate the effects of mitochondrial fission inhibitor, mdivi-1, on developmental competence and mitochondrial function of porcine embryos and primary cells. Presumptive porcine embryos were cultured in PZM-3 medium supplemented with mdivi-1 (0, 10 and 50 μM) for 6 days. Porcine fibroblast cells were cultured in growth medium with mdivi-1 (0 and 50 μM) for 2 days. Our results showed that the rate of blastocyst production and cell growth in the mdivi-1 (50 μM) treated group was lower than that of the control group (P < 0.05). Moreover, loss of mitochondrial membrane potential in the mdivi-1 (50 μM) treated group was increased relative to the control group (P < 0.05). Subsequent evaluation revealed that the intracellular levels of reactive oxygen species (ROS) and the apoptotic index were increased by mdivi-1 (50 μM) treatment (P < 0.05). Finally, the expression of mitochondrial fission-related protein (Drp 1) was lower in the embryos and cells in the mdivi-1-treated group than the control group. Taken together, these results indicate that mdivi-1 treatment may inhibit developmental competence and mitochondrial function in porcine embryos and primary cells.  相似文献   
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号