全文获取类型
收费全文 | 19825篇 |
免费 | 306篇 |
国内免费 | 9篇 |
专业分类
林业 | 3803篇 |
农学 | 1346篇 |
基础科学 | 150篇 |
3252篇 | |
综合类 | 1284篇 |
农作物 | 2222篇 |
水产渔业 | 2033篇 |
畜牧兽医 | 2729篇 |
园艺 | 1174篇 |
植物保护 | 2147篇 |
出版年
2022年 | 25篇 |
2021年 | 58篇 |
2020年 | 73篇 |
2019年 | 91篇 |
2018年 | 2792篇 |
2017年 | 2772篇 |
2016年 | 1258篇 |
2015年 | 133篇 |
2014年 | 90篇 |
2013年 | 170篇 |
2012年 | 992篇 |
2011年 | 2355篇 |
2010年 | 2222篇 |
2009年 | 1356篇 |
2008年 | 1527篇 |
2007年 | 1782篇 |
2006年 | 243篇 |
2005年 | 281篇 |
2004年 | 270篇 |
2003年 | 323篇 |
2002年 | 228篇 |
2001年 | 54篇 |
2000年 | 82篇 |
1999年 | 51篇 |
1998年 | 38篇 |
1997年 | 42篇 |
1996年 | 37篇 |
1995年 | 38篇 |
1994年 | 27篇 |
1993年 | 36篇 |
1992年 | 27篇 |
1991年 | 31篇 |
1990年 | 24篇 |
1989年 | 46篇 |
1988年 | 35篇 |
1987年 | 27篇 |
1985年 | 26篇 |
1984年 | 19篇 |
1983年 | 23篇 |
1982年 | 22篇 |
1981年 | 17篇 |
1978年 | 18篇 |
1977年 | 19篇 |
1976年 | 23篇 |
1974年 | 19篇 |
1973年 | 15篇 |
1972年 | 21篇 |
1971年 | 15篇 |
1966年 | 17篇 |
1939年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
991.
992.
R. M. Wallace D. Stanek S. Griese D. Krulak N. M. Vora L. Pacha V. Kan M. Said C. Williams T. H. Burgess S. S. Clausen C. Austin J. Gabel M. Lehman L. N. Finelli G. Selvaggi P. Joyce F. Gordin D. Benator A. Bettano S. Cersovsky C. Blackmore S. V. Jones B. D. Buchanan A. I. Fernandez D. Dinelli K. Agnes A. Clark J. Gill M. Irmler D. Blythe K. Mitchell T. J. Whitman M. J. Zapor S. Zorich C. Witkop P. Jenkins P. Mora D. Droller S. Turner L. Dunn P. Williams C. Richards G. Ewing K. Chapman C. Corbitt T. Girimont R. Franka S. Recuenco J. D. Blanton K. A. Feldman 《Zoonoses and public health》2014,61(8):560-570
This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post‐symptom onset. In response to an organ‐transplant‐related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post‐exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation. 相似文献
993.
Gao Zexia Wang Weimin Yang Yi Khalid Abbas Li Dapeng Zou Guiwei James S. Diana 《Fish physiology and biochemistry》2007,33(3):213-222
The peripheral blood cells of one-year-old Chinese sturgeon (Acipenser sinensis) have been studied by light microscopy and transmission electron microscopy. The erythrocyte count was 84.86 × 104 cell mm−3 in the peripheral blood of the fish and that of leukocytes was 2.24 × 104 cell mm−3. The erythrocytes and four main types of leucocyte—thrombocytes, lymphocytes, granulocytes (including neutrophils and eosinophils),
and monocytes, were identified in the peripheral blood. In addition to normal erythrocytes, reticulocytes and division of
erythrocytes were observed. Thrombocytes were the most numerous among the leukocytes, and the number of neutrophils with lobated
nuclei was larger than for other fish. The structures of the erythrocytes, lymphocytes, monocytes, granulocytes, and thrombocytes
of the fish were studied. The erythrocytes were almost completely devoid of organelles, except for some mitochondria and granules.
A large number of vacuoles and a few organelles were observed in cytoplasm of the monocytes. There were many microvilli on
the membrane and pseudopodia-like cytoplasm bulge in the lymphocytes. The neutrophils were round or oval in shape with bilobed,
trilobed, or multilobed nuclei whereas the eosinophils had big special granules, dark stained. There were many vesicles in
some thrombocytes, which were related to its phagocytosis; some thrombocytes had almost no cytoplasm or organelles. 相似文献
994.
Dal-Sang Jeong Enrique Blanco Gonzalez Kagayaki Morishima Katsutoshi Arai Tetsuya Umino 《Fisheries Science》2007,73(4):823-830
The genetic contribution of 51 broodstock, comprising 29 females and 22 males, reared at Hiroshima City Marine Products Promotion
Center for the production of stocked black sea bream was monitored during two consecutive years using seven microsatellite
DNA loci. The high discrimination ability of these markers was reflected in the polymorphic identification content (PIC=0.831), the exclusion probability (Q≈1), and the low probability of identity index (I=3.635−10). The total number of breeders contributing to the mating process was estimated at 32 (62.7%) in 2000 and 30 (58.8%) in 2001.
On pedigree reconstruction, 69.3% of the offspring were successfully assigned to a single broodstock pair. Loss of alleles
accounted for 16.9% during seed production; nevertheless, 90.9% of males and 69.0% of females participated in the mating process.
Based on microsatellite genetic tagging, 58.9% of the fish sampled during the two months after release were identified as
hatchery stock, presenting no significant differences from wild conspecifics in either fork length or body weight. 相似文献
995.
Manami Inaba Takeshi Kimura Rika Kikukawa Mitsuko Iwasaki Masato Nose Satoru Suzuki 《Fisheries Science》2007,73(3):615-622
ABSTRACT: Seasonal changes in the infection state of marine birnavirus (MABV) in Japanese flounder Paralichthys olivaceus and in rearing sea water are described. Sea water and 10–11 healthy fish were sampled monthly from April 2002 to February 2003. The MABV genome was detected throughout the year in > 80% of the fish examined at each sampling. The virus was isolated from the liver, kidney, and spleen, but not from the brain. The detection rate in each organ increased from April to October, and then decreased. Detection of virus antigen by the indirect fluorescent antibody technique also showed that the virus was present from spring to autumn (June–September) in the liver, kidney, and spleen, but not the brain. Sequence analysis of the MABV genome at the VP2–NS region revealed two specific mutations compared to the standard yellowtail strain (Y-6). It is suggested that the infection state of MABV in Japanese flounder changes to a latent or persistent infection after autumn. MABV was detected in sea water between September and February, suggesting that virus particles in the environment are relatively higher during cool seasons. 相似文献
996.
ABSTRACT: The relation between the density of fish and parameters such as body weight, condition factor and the hepatic triglyceride (TG) content of masu salmon Oncorhynchus masou juveniles after release into a natural stream were studied. Hatchery-reared juveniles of different sizes and numbers were released in May 1999, 2000 and 2001, and investigations were carried out from July to September each year. The density of fish was relatively high in 1999, when juveniles of the largest size and number were released, but then continued to decrease during the investigation. The hepatic TG content remained considerably low in 1999, and there was a significant negative correlation between the density of fish and the hepatic TG content of the juveniles caught over three years. The initial fish size and number at release as well as the nutritional condition of the juveniles may affect the density of fish after release. 相似文献
997.
998.
Stephen George David Burgess Michael Leaver Nick Frerichs 《Fish physiology and biochemistry》1992,10(1):43-54
Intraperitoneal injection of turbot with Cd induced the synthesis of a low molecular weight hepatic Cd-binding protein and a 500bp mRNA, which hybridised to a plaice metallothionein (MT) cRNA probe. The Cd-binding protein displayed cross-reactivity in a competitive ELISA with antiserum raised against rainbow trout MT and had the characteristic amino acid composition, metal stoichiometry and spectral characteristics of a Class I MT. Only one isoform was apparent on ion exchange chromatography. Southern blot analysis of DNA cleaved with four restriction enzymes suggested that only a single MT gene is present in turbot.In an established turbot fibroblast cell line, Cd induced MT mRNA and MT levels in a dose and time-dependent manner. MT was also induced by Cu, Hg and Zn but not Pb exposure. Physiological concentrations of glucocorticoids and sex hormones did not induce MT synthesis, although at high concentrations a positive response to corticosterone, dexamethasone, hydrocortisone or progesterone was observedin vitro indicating the possible presence of a functional steroid regulatory element in the fish MT gene.Abbreviations used AMP
adenosine monophosphate
- CHSE
chinook salmon embryo
- DMSO
dimethyl sulphoxide
- HPLC
high performance liquid chromatography
- KB
kenacid blue
- MT
metallothionein
- Mr
molecular weight (kDaltons)
- NR
neutral red
- PEG
polyethylene glycol
- RTH
rainbow trout hepatoma
- SDS
sodium dodecyl sulphate
- SSC
0.15M NaCl, 0.015M sodium citrate
- TF
turbot fibroblast 相似文献
999.
Four granular activated carbons (GACs) made of different materials were tested for removal of dissolved organic carbon (DOC) from artificial seawater of a recirculated aquarium. After 70 days in a continuous flow experiment, comparative removal data (grams of GAC required to remove 1 g of DOC) were coconut shell (491), hardwood (84·4), anthracite (837) and bone char (383), indicating the superior performance of hardwood. Scanning electron microscopy showed that microbial colonization of a sample material (hardwood) was slight and occurred exclusively at the surface. Biological enhancement of GAC was considered to be unimportant as a mechanism for DOC removal. 相似文献
1000.
Shinsuke Torisawa Tsutomu Takagi Yasunori Ishibashi Yoshifumi Sawada Takeshi Yamane 《Fisheries Science》2007,73(5):1202-1204