全文获取类型
收费全文 | 8758篇 |
免费 | 522篇 |
国内免费 | 50篇 |
专业分类
林业 | 556篇 |
农学 | 451篇 |
基础科学 | 87篇 |
1535篇 | |
综合类 | 631篇 |
农作物 | 456篇 |
水产渔业 | 683篇 |
畜牧兽医 | 4018篇 |
园艺 | 127篇 |
植物保护 | 786篇 |
出版年
2023年 | 82篇 |
2022年 | 144篇 |
2021年 | 265篇 |
2020年 | 254篇 |
2019年 | 322篇 |
2018年 | 281篇 |
2017年 | 311篇 |
2016年 | 314篇 |
2015年 | 221篇 |
2014年 | 311篇 |
2013年 | 508篇 |
2012年 | 487篇 |
2011年 | 544篇 |
2010年 | 264篇 |
2009年 | 298篇 |
2008年 | 440篇 |
2007年 | 426篇 |
2006年 | 388篇 |
2005年 | 360篇 |
2004年 | 332篇 |
2003年 | 296篇 |
2002年 | 340篇 |
2001年 | 239篇 |
2000年 | 242篇 |
1999年 | 204篇 |
1998年 | 59篇 |
1997年 | 58篇 |
1996年 | 57篇 |
1995年 | 53篇 |
1994年 | 40篇 |
1993年 | 40篇 |
1992年 | 81篇 |
1991年 | 54篇 |
1990年 | 62篇 |
1989年 | 69篇 |
1988年 | 63篇 |
1987年 | 52篇 |
1986年 | 46篇 |
1985年 | 58篇 |
1984年 | 40篇 |
1983年 | 43篇 |
1982年 | 30篇 |
1980年 | 25篇 |
1979年 | 42篇 |
1977年 | 26篇 |
1975年 | 23篇 |
1974年 | 25篇 |
1973年 | 25篇 |
1972年 | 24篇 |
1970年 | 26篇 |
排序方式: 共有9330条查询结果,搜索用时 15 毫秒
41.
42.
Kosar Gharib-Naseri Sara de Las Heras-Saldana Sarbast Kheravii Lihong Qin Jingxue Wang Shu-Biao Wu 《动物营养(英文)》2021,7(1):239
Necrotic enteritis (NE) is an important enteric disease in poultry and has become a major concern in poultry production in the post-antibiotic era. The infection with NE can damage the intestinal mucosa of the birds leading to impaired health and, thus, productivity. To gain a better understanding of how NE impacts the gut function of infected broilers, global mRNA sequencing (RNA-seq) was performed in the jejunum tissue of NE challenged and non-challenged broilers to identify the pathways and genes affected by this disease. Briefly, to induce NE, birds in the challenge group were inoculated with 1 mL of Eimeria species on day 9 followed by 1 mL of approximately 108 CFU/mL of a NetB producing Clostridium perfringens on days 14 and 15. On day 16, 2 birds in each treatment were randomly selected and euthanized and the whole intestinal tract was evaluated for lesion scores. Duodenum tissue samples from one of the euthanized birds of each replicate (n = 4) was used for histology, and the jejunum tissue for RNA extraction. RNA-seq analysis was performed with an Illumina RNA HiSeq 2000 sequencer. The differentially expressed genes (DEG) were identified and functional analysis was performed in DAVID to find protein–protein interactions (PPI). At a false discovery rate threshold <0.05, a total of 377 DEG (207 upregulated and 170 downregulated) DEG were identified. Pathway enrichment analysis revealed that DEG were considerably enriched in peroxisome proliferator-activated receptors (PPAR) signaling (P < 0.01) and β-oxidation pathways (P < 0.05). The DEG were mostly related to fatty acid metabolism and degradation (cluster of differentiation 36 [CD36], acyl-CoA synthetase bubblegum family member-1 [ACSBG1], fatty acid-binding protein-1 and -2 [FABP1] and [FABP2]; and acyl-coenzyme A synthetase-1 [ACSL1]), bile acid production and transportation (acyl-CoA oxidase-2 [ACOX2], apical sodium–bile acid transporter [ASBT]) and essential genes in the immune system (interferon-, [IFN-γ], LCK proto-oncogene, Src family tyrosine kinase [LCK], zeta chain of T cell receptor associated protein kinase 70 kDa [ZAP70], and aconitate decarboxylase 1 [ACOD1]). Our data revealed that pathways related to fatty acid digestion were significantly compromised which thereby could have affected metabolic and immune responses in NE infected birds. 相似文献
43.
Sparkes A Wray J Leece E de Risio L Murphy S Furneaux R Sansom J Coatesworth J 《The Veterinary record》2007,161(24):826; discussion 826-826; discussion 827
44.
45.
Sophie Favril Emmelie Stock Sophie Hernot Myriam Hesta Ingeborgh Polis Katrien Vanderperren Hilde de Rooster 《Veterinary and comparative oncology》2019,17(1):89-98
Sentinel lymph node (SLN) mapping is a valuable and crucial diagnostic procedure in staging malignancies. We compared two non‐invasive techniques, near‐infrared (NIR) fluorescence imaging and contrast‐enhanced ultrasound (CEUS), to identify the SLNs in three superficial anatomical regions in an animal model. Six healthy laboratory dogs were included in a proof‐of‐concept trial. A NIR fluorescent dye (Indocyanine Green) and microbubbles (Sonovue) were consecutively injected subdermally in the Inguinal, axillary and popliteal region to map the SLNs. Transcutaneous NIR fluorescence imaging identified SLNs in 17 out of a total of 18 occasions. CEUS identified SLNs in all regions (18/18). Whereas NIR fluorescence imaging performed better in the visualization of the afferent lymphatic tract, CEUS demonstrated different filling patterns of the SLNs, a feature potentially critical for the concept of SLN mapping in cancer patients. Both NIR fluorescence imaging and CEUS are safe, non‐invasive, practical and accurate methods to perform real‐time transcutaneous SLN mapping with potential in a clinical setting. 相似文献
46.
C. de Fourmestraux O. Geffroy B. Siliart O. Albaric C. Tessier 《Equine Veterinary Education》2014,26(1):34-39
The surgical success of laparoscopic castration without orchidectomy results from avascular necrosis of the testes. However, failures and subsequent production of testosterone and stallion‐like behaviour have been previously identified. Laparoscopic castration without removal of the testes was performed in 32 horses with 2 normal descended scrotal testes between July 2006 and October 2012. The objectives of our study were to evaluate the success rate of laparoscopic castration without orchidectomy on descended testes in our population and assess complications and recovery time. Endocrine tests were performed after surgery and owners also asked to report on their horse's behaviour and ability to resume exercise. Castration was deemed successful if endocrine test results were in accordance with gelding values. Failed horses were castrated using a conventional technique and histology performed when possible. Basal testosterone levels decreased below 3 nmol/l after surgery in 30/32 cases. However, in 2 horses, stallion behaviour persisted and histological evaluation after inguinal castration showed residual viable tissue. Two horses maintained high testosterone levels after surgery associated with stallion‐like behaviour. Based on these results, 12.5% of horses (4/32 horses) failed to be considered a gelding based on either endocrine tests and/or histology. All horses, with one exception, were able to resume exercise less than a week after the procedure. Laparoscopic castration without orchidectomy appears to be a safe procedure. When assessing the success of laparoscopic castration, our total failure rate was 12.5% (4/32 horses) which is significantly higher than previously reported. 相似文献
47.
Schwan EV Miller DB de Kock D van Heerden A 《Journal of the South African Veterinary Association》2000,71(3):197-200
Acute liver failure was diagnosed in a 12-year-old cat. Fine needle aspirate cytology revealed high numbers of unsheathed microfilariae and a hepatocellular reaction with no evidence of bacterial infection. The microfilariae were identified as those of Dirofilaria repens by acid phosphatase staining. The high number of microfilariae seen in both the blood and the liver aspirate samples as well as the favourable response to ivermectin amongst other drugs administered, is suggestive that D. repens was the cause of the liver insult. A positive result obtained with an antigen-capture ELISA (Dirochek) for Dirofilaria immitis antigen was interpreted as false. This is the 1st report of Dirofilaria repens for South Africa. 相似文献
48.
49.
D T de Waal J van Heerden F T Potgieter 《The Onderstepoort journal of veterinary research》1987,54(4):561-568
Serologically negative horses, as determined with the indirect fluorescent antibody test (IFA), were infected with Babesia equi and 60 days later with Babesia caballi. The only clinical signs of disease observed in these animals were a febrile reaction and slight icterus. Haematological changes included a drop in haematocrit and haemoglobin concentration, as well as lowered platelet counts. The serum concentrations of albumin, iron and phosphorus were lowered. Mildly elevated serum bilirubin and fibrinogen concentrations were observed. Antibody titres were determined with the IFA and complement fixation (CF) tests. Antibodies to B. equi were first detected between Days 10-19 and 12-38 with the IFA and CF test, respectively, while the corresponding IFA periods for B. caballi were 6-8 days after infection. The parasitaemia of both B. equi and B. caballi infections never reached the 1% level. 相似文献