全文获取类型
收费全文 | 4677篇 |
免费 | 245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 | 366篇 |
农作物 | 695篇 |
水产渔业 | 403篇 |
畜牧兽医 | 1891篇 |
园艺 | 69篇 |
植物保护 | 240篇 |
出版年
2023年 | 31篇 |
2022年 | 88篇 |
2021年 | 163篇 |
2020年 | 98篇 |
2019年 | 122篇 |
2018年 | 148篇 |
2017年 | 137篇 |
2016年 | 153篇 |
2015年 | 154篇 |
2014年 | 209篇 |
2013年 | 301篇 |
2012年 | 329篇 |
2011年 | 383篇 |
2010年 | 225篇 |
2009年 | 202篇 |
2008年 | 293篇 |
2007年 | 298篇 |
2006年 | 265篇 |
2005年 | 221篇 |
2004年 | 216篇 |
2003年 | 187篇 |
2002年 | 140篇 |
2001年 | 134篇 |
2000年 | 92篇 |
1999年 | 59篇 |
1998年 | 35篇 |
1997年 | 27篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 24篇 |
1989年 | 18篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 8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4924条查询结果,搜索用时 15 毫秒
71.
72.
A two‐year‐old Rottweiler presented for acute onset of a right hindlimb lameness 20 weeks after a cementless total hip replacement (THR) and 16 weeks after open reduction to address luxation of the THR. Radiographs revealed periosteal proliferation of the medial acetabulum and a stable implant. Synovial fluid cytology was consistent with inflammatory joint fluid. Treatment consisted of surgical debridement and intravenous and oral antibiotics. THR implants were not removed. Culture of tissue removed from the THR site yielded growth of Pseudomonas and Staphylococcus species. Lameness resolved 2 months after surgery. Twenty months after surgery, the dog was exercising normally with no clinical lameness and pelvic radiographs revealed no evidence of implant loosening and markedly decreased periosteal reaction. To the authors’ knowledge, this is the first report of an infected THR site successfully treated without prosthesis explantation in the dog. 相似文献
73.
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
74.
Kim CS Koh PO Cho JH Park OS Cho KW Kim GS Won CK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(6):653-655
A male deformed Korean native calf was examined macroscopically. The deformed calf had no caudal vertebral columns from 5th lumbar vertebra, sacrum and coccygeal vertebrae. The spinal cord was terminated in the vertebral foramen of the 3rd lumbar vertebra. The cervical vertebrae had scoliosis and the 3rd and 4th cervical vertebrae were fused. The 2nd and 3rd lumbar vertebrae were fused and the left and right transverse processes of the 4th lumbar vertebra articulated with ala of the ilium. The rectum was greatly expanded by the imperforate anus and a rectourethral fistula was formed between the rectum and urethra. The deformed calf was recorded as a first documentation of sacrocaudal agenesis confirmed in a Korean native calf. 相似文献
75.
Ticehurst K Zaki S Maddern K Lingard A Barrs V Malik R 《Journal of Feline Medicine and Surgery》2007,9(6):521-525
A 14-year-old neutered male domestic shorthaired cat was presented to the University Veterinary Centre Sydney for evaluation and treatment of dental disease. This cat developed an unusual bradyarrhythmia under anaesthesia. The possible causes and treatment of the dysrythmia are discussed. 相似文献
76.
Kim UH Suh GH Hur TY Kang SJ Kang HG Park SB Kim HS Kim IH 《The Journal of reproduction and development》2007,53(3):639-645
This study compared two types of controlled internal drug release (CIDR)-based timed artificial insemination (TAI) protocol for treatment of repeat breeder dairy cows. In the first trial of the experiment, 55 repeat breeder cows were randomly assigned to the following two treatments. (1) In the EB group, a CIDR device was inserted into the cows, and then the cows were administered an injection of 1 mg estradiol benzoate (EB) plus 50 mg progesterone (P4; Day 0). On Day 7, they were given an injection of PGF(2alpha) and the CIDR device was removed. The cows were given an injection of 1 mg EB on Day 8 and were subjected to TAI 30 h later (n=27). (2) In the gonadotrophin releasing hormone (GnRH) group, a CIDR device was inserted into the cows, and then the cows were administered an injection of 250 microg gonadorelin (GnRH; Day 0). On Day 7, they were given an injection of PGF(2alpha) and the CIDR device was removed. The cows were given an injection of 250 microg GnRH on Day 9 and were subjected to TAI 17 h later (n=28). In the second trial, 41 repeat breeder cows that were confirmed as not pregnant in the first trial were randomly assigned to the same two treatments used in the first trial (an EB group of 20 cows and a GnRH group of 21 cows). The ovaries of 15 cows from each group were examined by transrectal ultrasonography in order to observe the changes in ovarian structures, and blood samples were collected for analysis of serum P4 concentrations. The pregnancy rates following TAI in the first (18.5 vs. 32.1%) and second (40.0 vs. 38.1%) trials and the combined rates (27.7 vs. 34.7%) did not differ between the EB and GnRH groups. The proportions of cows with follicular wave emergence within 7 days did not differ between the EB (12/15) and GnRH groups (13/15). The interval to wave emergence was shorter (P<0.01) in the GnRH group than in the EB group, but there was no difference in the mean diameters of dominant follicles on Day 7 between the groups. Moreover, the proportions of cows with synchronized ovulation following a second EB or GnRH treatment did not differ between the groups. In conclusion, treatment with either EB or GnRH in a CIDR-based TAI protocol results in synchronous follicular wave emergence, follicular development, synchronous ovulation, and similar pregnancy rates for TAI in repeat breeder cows. 相似文献
77.
78.
Effects of chilled drinking water on the performance of lactating sows and their litters during high ambient temperatures under farm conditions 总被引:1,自引:0,他引:1
J.H. Jeon S.C. Yeon Y.H. Choi W. Min S. Kim P.J. Kim H.H. Chang 《Livestock Science》2006,105(1-3):86-93
Heat stress has detrimental effects on lactating sows and their litters, including decreased feed intake and milk production in sows and decreased weight gain in their offspring. It also increases respiration rate, rectal temperature, and weaning to estrus interval in sows. This study was conducted to investigate the effects of chilled water (CW) on the performance of lactating sows and their litters exposed to high ambient temperatures for 21 days. Ninety multiparous sows (Yorkshire × Landrace; parity range: 2 to 5) and their litters (Yorkshire × Landrace × Duroc) were divided into 3 blocks (30 each). Sows and their litters within each block were randomly assigned to one of the three treatment groups (n = 10 each). Each group was provided with drinking water at 10, 15, or 22 °C (control) under farm conditions where ambient temperature above 25 °C was consistent during the experimental period. Sows on CW (both 10 and 15 °C) consumed more feed and water than did control (P < 0.01) and higher estimated milk production compared with control (P < 0.01), but had lower rectal temperature and respiration rate compared with control (P < 0.01). Mean weaning weight (P < 0.01) and average daily gain (P < 0.01) of litters in CW groups were higher than those in control group. There were no differences in the measured variables, with the exception of the respiration rates, between the two CW treatment groups. These results suggest that CW may improve the performance of sows and their litters exposed to high ambient temperatures and the 15 °C water, from an energy viewpoint, may be more effective. 相似文献
79.
80.