全文获取类型
收费全文 | 4566篇 |
免费 | 233篇 |
国内免费 | 2篇 |
专业分类
林业 | 199篇 |
农学 | 233篇 |
基础科学 | 13篇 |
815篇 | |
综合类 | 358篇 |
农作物 | 694篇 |
水产渔业 | 401篇 |
畜牧兽医 | 1779篇 |
园艺 | 69篇 |
植物保护 | 240篇 |
出版年
2023年 | 29篇 |
2022年 | 88篇 |
2021年 | 163篇 |
2020年 | 97篇 |
2019年 | 121篇 |
2018年 | 144篇 |
2017年 | 134篇 |
2016年 | 146篇 |
2015年 | 150篇 |
2014年 | 205篇 |
2013年 | 269篇 |
2012年 | 328篇 |
2011年 | 383篇 |
2010年 | 220篇 |
2009年 | 199篇 |
2008年 | 292篇 |
2007年 | 296篇 |
2006年 | 263篇 |
2005年 | 218篇 |
2004年 | 214篇 |
2003年 | 186篇 |
2002年 | 140篇 |
2001年 | 131篇 |
2000年 | 92篇 |
1999年 | 57篇 |
1998年 | 28篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 22篇 |
1989年 | 17篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1980年 | 5篇 |
1978年 | 11篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 4篇 |
排序方式: 共有4801条查询结果,搜索用时 15 毫秒
111.
112.
Treatment of dogs with oral melanoma by hypofractionated radiation therapy and platinum-based chemotherapy (1987-1997) 总被引:1,自引:0,他引:1
Freeman KP Hahn KA Harris FD King GK 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(1):96-101
This retrospective study in 39 dogs with incompletely resected oral melanoma examined the efficacy of hypofractionated radiation therapy and platinum-containing chemotherapy. All dogs were completely staged, with the majority of dogs classified as stage 1. Dogs received 6 weekly fractions of 6-gray (Gy) megavoltage irradiation with a cobalt-60 unit or a 4-MeV (megaelectron volts) linear accelerator. Dogs received cisplatin (10-30 mg/m2 IV) or carboplatin (90 mg/m2 IV) chemotherapy 60 minutes before radiation delivery. Durations of local control, metastasis-free survival time, and overall survival time were recorded. By the Kaplan-Meier method, 15% of the dogs had local recurrence within a median time of 139 days. Fifty-one percent of the dogs developed metastatic disease within a median time of 311 days (range, 24-2, 163 days). Median survival time for all 39 dogs was 363 days. The combined use of chemotherapy and radiation therapy in this protocol provided local control consistent with previous studies. Low-dose chemotherapy was used with the intent of enhancing radiation therapy for the local control of an incompletely excised tumor. Survival times were longer than previously reported for dogs with oral malignant melanoma. Additional studies are required to determine whether these results were due to the effects of chemotherapy on microscopic disease or the enhanced local control provided by chemoradiation therapy. 相似文献
113.
Self-actuating materials capable of transforming between three-dimensional shapes have applications in areas as diverse as biomedicine, robotics, and tunable micro-optics. We introduce a method of photopatterning polymer films that yields temperature-responsive gel sheets that can transform between a flat state and a prescribed three-dimensional shape. Our approach is based on poly(N-isopropylacrylamide) copolymers containing pendent benzophenone units that allow cross-linking to be tuned by irradiation dose. We describe a simple method of halftone gel lithography using only two photomasks, wherein highly cross-linked dots embedded in a lightly cross-linked matrix provide access to nearly continuous, and fully two-dimensional, patterns of swelling. This method is used to fabricate surfaces with constant Gaussian curvature (spherical caps, saddles, and cones) or zero mean curvature (Enneper's surfaces), as well as more complex and nearly closed shapes. 相似文献
114.
Shin JH Sakoda Y Kim JH Ochiai K Umemura T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(11):1167-1169
Rabbits were immunized with inactivated influenza virus via the subarachnoidal (SA) or subcutaneous (SC) route, and the antibody titers in cerebrospinal fluid (CSF) and serum were assayed. There were no nervous signs or morphological lesions related to SA immunization. In the SC group, the antibody titer was elevated in serum, but not elevated in CSF. In the SA group, the antibody titer was significantly elevated in serum and even in CSF, and their antibody titers were much greater than in the SC group. The present results suggest that intrathecal immunization is more effective than SC immunization at inducing a protective immune response against the transneural spread of viruses. 相似文献
115.
Park C Yoo JH Jeon HW Kang BT Kim JH Jung DI Lim CY Lee HJ Hahm DH Woo EJ Park HM 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(9):951-955
Three dogs were presented to us for evaluation of cardiac problems. Electrocardiographic recordings revealed severe tachyarrhythmia and atrial fibrillation with ventricular tachycardia in 2 of the 3 dogs. The echocardiographic findings of the 3 dogs revealed markedly decreased fractional shortening and a marked increase in E-point septal separation. Based on the results of electrocardiographic and echocardiographic evaluation, the 3 dogs were diagnosed as dilated cardiomyopathy (DCM). The dogs were treated with conventional cardiac medication, but cardiac function did not improve and the clinical signs remained. We subsequently attempted treatment with granulocyte-colony stimulating factor (G-CSF; 10 microg/kg, subcutaneously). The specific purpose of G-CSF therapy for DCM was to improve cardiac function and a significant improvement in cardiac function was confirmed. The three dogs had no treatment side effects. This case report suggests that G-CSF might have therapeutic effects for medically refractory DCM in dogs. 相似文献
116.
Matsuda K Kim BS Whang IS Lim CW Baek BK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(9):971-975
Strongyloides venezuelensis (SVZ) infection was chronologically monitored in 85 Sprague-Dawley rats (SDR), which were orally inoculated with approximately 1,000 infective larvae. In order to describe the characteristics of migrating larvae (MLS) in various visceral organs (the liver, lung, cardiac blood, and small intestine), 5 SDR were sacrificed at 20 min, 45 min, 1 hr, 2 hr, 3 hr, 4 hr, 8 hr, 12 hr, 16 hr, 48 hr, 72 hr, 96 hr, 120 hr, 144 hr, 168 hr and 192 hr post inoculation (PI). MLS were recovered from the liver and blood 20 and 45 min PI and measured 788 +/- 26 microm and 846 +/- 40 microm in length, respectively. MLS were first observed in the lung tissue 45 min PI and measured 925 +/- 38 microm on the average. In the trachea, MLS measuring 849 +/- 75 microm appeared 3 to 96 hrs PI. Adult worms (AWS) measuring 1,926 +/- 521 microm to 2,956 +/- 159 microm in length were observed in the small intestine from 120 hr PI. The worms appeared to mature more than 168 hr PI and attained the average maximum length of 2,420 +/- 532 microm. At 3 hr PI focal hyperemic and necrotic lesions were evidently observed in the liver and lung, together with eosinophilic infiltration in the stomach, liver, and lung. The parasites were histologically detectable in the lung tissues but were very difficult to find in the liver and the epithelial layer of small intestine. These data demonstrate that SVZ parasites take 20 min to reach the liver via the stomach and only three hours to reach the trachea through the same route. The development from eggs to adults takes 168 hr in the SDR model. 相似文献
117.
S.H. Kim C.E. Niedziela Jr. P.V. Nelson A.A. De Hertogh W.H. Swallow N.C. Mingis 《Scientia Horticulturae》2007
One-year old scale bulblets of Lilium longiflorum Thunb. ‘Nellie White’ (Easter lily) were grown for 107 days during growth period 1 (GP-1) in six growth chambers under constant day/night temperature regimes of 30/26, 26/22, 22/18, 18/14, 14/10 and 10/6 °C. Subsequently, half of the plants in each temperature regime were transferred to 18/14 °C and the other half continued at the six constant temperature regimes. Both groups of plants were grown for an additional 89 days in growth period 2 (GP-2). Continuous temperatures of 26/22, 26/22–22/18 and 26/22–18/14 °C produced the greatest increase in basal bulb fresh weight (the main planted bulb), basal bulb circumference and stem bulb fresh weight, respectively. However, shifting these optimal temperatures to 18/14 °C during GP-2 resulted in a lower increase in basal bulb fresh weight and circumference. The optimum range for stem bulb production was expanded to 30/26–14/10 °C by shifting to 18/14 °C. The greatest increase for basal root growth occurred at 14/10–10/6 °C and for stem root growth at 14/10 °C. The temperature shift did not affect either root type. Maximum increase for stem length was at 26/22 and 22/18 °C and for stem plus leaf weight at 14/10 °C under constant temperature regimes. Transferring the plants from 10/6 to 18/14 °C resulted in the greatest increase in stem length and from 10/6 and 14/10 to 18/14 °C in the greatest increase in stem plus leaf weight. The greatest increase in the number of leaves occurred at 26/22 and 10/6 °C, but this growth parameter was unaffected by shifting to 18/14 °C, indicating that leaf number was determined in GP-1. Bulbils developed only when bulbs at high GP-1 temperature regimes (30/26 and 26/22 °C) were transferred to 18/14 °C during GP-2. Lower temperatures tended to favor an increase in flower bud production under continuous temperature regimes, while shifting to 18/14 °C increased flower bud production after initially high and low temperatures. Meristem abortion was greatest at 30/26 °C followed by 26/22 °C, but was not affected by temperature shifts in GP- 2. Thus, it is concluded that the abortion was induced or initiated during GP-1. 相似文献
118.
Myung-Hoo Kim Ji-Young Yang Santi Devi Upadhaya Hyun-Jun Lee Cheol-Heui Yun Jong K. Ha 《Journal of veterinary science (Suw?n-si, Korea)》2011,12(2):151-157
The purpose of our study was to investigate changes in immunological parameters induced by weaning stress (including milk restriction) in calves. Fifteen Holstein calves were subjected to weaning at 6 weeks of age. Blood samples were collected at -14, -7, -2, 1, 3, and 5 days post-weaning (DPW; 0 DPW = 42 days). Weaning caused significant (p < 0.01) increases in the neutrophil (NE):lymphocyte (LY) ratio at 5 DPW with a significant (p < 0.05) reduction of LYs. The concentration of acute-phase proteins (haptoglobin and serum amyloid A) also increased significantly (p < 0.05) at 3 and 5 DPW compared to -2 DPW. Levels of the iron-binding protein lactoferrin decreased significantly (p < 0.05) after weaning. Serum tumor necrosis factor-α and cortisol levels were elevated (p < 0.05) at 3 DPW, while those of serum interferon-γ decreased (p < 0.05) at 1 and 3 DPW compared to levels observed before weaning. Weaning significantly (p < 0.05) decreased the percentage of CD25+ T cells in the peripheral blood. In conclusion, weaning stress affected the NE:LY ratio along with the levels of acute phase proteins, lactoferrin, cortisol, and inflammatory cytokines in the peripheral blood of calves. Weaning stress may induce an acute phase response possibly through the elevation of cortisol production and modulation of inflammatory cytokines. 相似文献
119.
Jeong MB Kim YJ Yi NY Park SA Kim WT Kim SE Chae JM Kim JT Lee H Seo KM 《Veterinary ophthalmology》2007,10(6):376-379
OBJECTIVE: To examine the feasibility and accuracy of a handheld rebound tonometer, TonoVet, and to compare the intraocular pressure (IOP) readings of the TonoVet with those of an applanation tonometer, TonoPen XL, in normal Eurasian Eagle owls. ANIMALS STUDIED: Ten clinically normal Eurasian Eagle owls (20 eyes). PROCEDURES: Complete ocular examinations, using slit-lamp biomicroscopy and indirect ophthalmoscopy, were conducted on each raptor. The IOP was measured bilaterally using a rebound tonometer followed by a topical anesthetic agent after 1 min. The TonoPen XL tonometer was applied in both eyes 30 s following topical anesthesia. RESULTS: The mean +/- SD IOP obtained by rebound tonometer was 10.45 +/- 1.64 mmHg (range 7-14 mmHg), and by applanation tonometer was 9.35 +/- 1.81 mmHg (range 6-12 mmHg). There was a significant difference (P = 0.001) in the IOP obtained from both tonometers. The linear regression equation describing the relationship between both devices was y = 0.669x + 4.194 (x = TonoPen XL and y = TonoVet). The determination coefficient (r(2)) was r(2) = 0.550. CONCLUSIONS: The results suggest that readings from the rebound tonometer significantly overestimated those from the applanation tonometer and that the rebound tonometer was tolerated well because of the rapid and minimal stress-inducing method of tonometry in the Eurasian Eagle owls, even without topical anesthesia. Further studies comparing TonoVet with manometric measurements may be necessary to employ rebound tonometer for routine clinical use in Eurasian Eagle owls. 相似文献
120.
Hyeshin Hwang Younghye Ro Hyunkyoung Lee Jihyeon Kim Kyunghyun Lee Eun-Jin Choi You-Chan Bae ByungJae So Dohoon Kwon Ho Kim Inhyung Lee 《Journal of veterinary science (Suw?n-si, Korea)》2022,23(5)
BackgroundSince 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015–2016 identified Setaria digitata as the causative agent.ObjectivesThis study is an epidemiological investigation to find out risk factors related to the rapid increase in hindlimb ataxia of horses due to aberrant parasites in South Korea.MethodsAn epidemiological investigation was conducted on 155 cohabiting horses in 41 horse ranches where the disease occurred. The surrounding environment was investigated at the disease-causing horse ranches (n = 41) and 20, randomly selected, non-infected ranches.ResultsHindlimb ataxia was confirmed in nine cohabiting horses; this was presumed to be caused by ectopic parasitism. Environments that mosquitoes inhabit, such as paddy fields within 2 km and less than 0.5 km from a river, had the greatest association with disease occurrence.ConclusionsMost horse ranches in South Korea are situated in favorable environments for mosquitoes. Moreover, the number of mosquitoes in the country has increased since 2013 due to climate change. Additional research is required; however, these data show that it is necessary to establish guidelines for the use of anthelmintic agents based on local factors in South Korea and disinfection of the environment to prevent disease outbreaks. 相似文献