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91.
To tackle the growing problem of antibiotic resistance, it is essential to identify new bioactive compounds that are effective against resistant microbes and safe to use. Natural products and their derivatives are, and will continue to be, an important source of these molecules. Sea sponges harbour a diverse microbiome that co-exists with the sponge, and these bacterial communities produce a rich array of bioactive metabolites for protection and resource competition. For these reasons, the sponge microbiota constitutes a potential source of clinically relevant natural products. To date, efforts in bioprospecting for these compounds have focused predominantly on sponge specimens isolated from shallow water, with much still to be learned about samples from the deep sea. Here we report the isolation of a new Micromonospora strain, designated 28ISP2-46T, recovered from the microbiome of a mid-Atlantic deep-sea sponge. Whole-genome sequencing reveals the capacity of this bacterium to produce a diverse array of natural products, including kosinostatin and isoquinocycline B, which exhibit both antibiotic and antitumour properties. Both compounds were isolated from 28ISP2-46T fermentation broths and were found to be effective against a plethora of multidrug-resistant clinical isolates. This study suggests that the marine production of isoquinocyclines may be more widespread than previously supposed and demonstrates the value of targeting the deep-sea sponge microbiome as a source of novel microbial life with exploitable biosynthetic potential.  相似文献   
92.
ABSTRACT

Most of the sugarcane (interspecific hybrids of Saccharum sp.) production in Florida is on organic soils. Supplemental phosphorus (P) fertilizer is often applied for optimum yields, but producers are required to reduce P levels in farm drainage waters. The objectives of this study were to relate optimum leaf P tissue concentration with yield in organic soil, and to determine optimum leaf sampling dates during the summer. Eight genotypes were planted at two locations, eight additional genotypes were planted at a third location, and eight more genotypes were planted at a fourth location. Crops were grown for three years. Measurements of leaf P concentration were repeated during growth seasons and over crop years for a total of six sampling dates at each location. Three fertilizer P treatments (0, 24, and 48 kg ha?1 yr?1) were applied to all genotypes at each location. Leaf samples were partitioned into early-, mid-, and late-summer dates. Early-leaf samples had the widest range in leaf P concentrations compared with mid- and late-season leaf samples. Correlation analyses of yield vs. leaf P concentration across all treatments in early- and mid-summer were statistically significant (P < 0.05), but coefficients were low (r = 0.14 and 0.26, respectively). No consistent relationship across locations described the effect of leaf P tissue concentration on yield. Leaf P concentrations could not provide accurate P fertilization rates that will give maximum sugarcane yields and prevent over-fertilization of P. The highest potential for relating leaf P concentrations with yield appears to be from early leaf samples.  相似文献   
93.
Populations of the green peach aphid,Myzus persicae (Sulzer), and the potato aphid,Macrosiphum euphorbiae (Thomas), were observed on 27 named varieties of Irish potatoes in the Yakima Valley of Washington intermittently from 1947 through 1968. The Epicure, Great Scot, and B5141-6 varieties produced relatively fewer green peach aphids than other varieties tested; Bliss Triumph and Red Pontiac produced relatively fewer potato aphids. Except for Doebay Red, the red-skinned varieties, Bliss Triumph, Red McLure, Norland, and Earnly Rose, were extremely to moderately productive of the green peach aphid. No correlation was apparent between abundance of aphids and the specific gravity or yield of tubers.  相似文献   
94.
95.
Summary The chloroplast DNA of 27 potato cultivars and 2 wild species has been examined by Southern blotting using probes representing the entire chloroplast genome of barley. 16% of the probe × enzyme combinations detected polymorphism between the potato cultivars. Cvs Maris Piper, Croft, Shelagh, Stormont Enterprise and Estima and the wild species could be distinguished from the other cultivars by their chloroplast DNA restriction patterns. These results are discussed in relation to cytoplasmic diversity and potato improvement.  相似文献   
96.
Webb  Hailey  Barnes  Nathaniel  Powell  Scott  Jones  Clain 《Precision Agriculture》2021,22(6):1803-1815
Precision Agriculture - Soil acidification is a growing problem in semi-arid agroecosystems. In the state of Montana, USA, soil pH levels below 5.5 have been documented in nearly half of the...  相似文献   
97.
Examples of equine disease surveillance at the local, regional, national and international level are discussed in this article. Reporting systems at each level are also considered, and the increasing importance of laboratory confirmed diagnoses is emphasized. The need to develop national disease reporting systems is addressed, particularly with respect to conforming to international trading standards.  相似文献   
98.
The objective of this research was to measure the effects of endophyte-infected tall fescue seed extract and various alkaloids associated with the endophyte on in vitro prolactin secretion by rat hemipituitaries. Rat anterior pituitaries (AP) were dissected into halves and placed in temperature-controlled culture chambers (37 degrees C). The tissue was perfused with culture media at a flow rate of 12 mL/h. After perfusion for at least 90 min with control media, AP halves were exposed to their respective treatments for 15 min before they were returned to the control media. The treatments for Exp. 1 were .01 micrograms of alpha-ergocryptine/mL of culture medium, .01 microgram of ergonovine/mL of culture medium, .01 gram-equivalents of endophyte-infected tall fescue seed/mL of culture medium, and .01 gram-equivalents of endophyte free tall fescue seed/mL of culture medium. Treatments for Exp. 2 consisted of 10(-4), 10(-6), and 10(-8) M concentrations of perloline, N-formyl loline, N-acetyl loline, N-methyl loline, and alpha-ergocryptine. alpha-Ergocryptine suppressed (P less than .10) prolactin secretion in both experiments. Ergonovine and perloline both stimulated (P less than .10) prolactin secretion. The loline alkaloids (N-formyl loline, N-acetyl loline, N-methyl loline) had no effect on prolactin secretion. The endophyte-infected seed extract treatment suppressed (P less than .10) prolactin secretion. The endophyte-free seed extract treatment had no effect on prolactin secretion. In Exp. 2, prolactin secretion from AP responded to alpha-ergocryptine treatment in a dose-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
99.
In 1980 and 1981, pitfall traps and an insect vacuum net were used to sample polyphagous predators in plots of winter wheat treated or not treated with herbicides. Dense populations of broad-leaved and grass weeds occurred in untreated plots. Significantly more large carabids (Pterostichus melanarius and P. madidus) were caught in pitfall traps in treated than in untreated plots, where their activity may have been reduced by the vegetation. Numbers of the carabids Loricera pilicornis, Agonum dorsale and Amara species, of the staphylinids Philonthus cognatus, Tachinus signatus, Tachyporus species and Aleocharinae and of larvae of both families were significantly reduced by herbicide treatments. Some species were unaffected by the treatments. Cereal aphids were sparse during the trials and their numbers were unaffected by herbicide treatments. In 1981, more Sitobion avenae occurred on the cultivar Maris Huntsman than on Kador.  相似文献   
100.
Peanut agglutinin (PNA) and surface immunoglobulin (SIg) were investigated as markers for T and B lymphocytes in blood and lymphoid tissues of dogs of various ages. In the blood study, 4 age groups (n = 8 dogs/group) were used. The mean (+/- SD) percentages of PNA-positive (PNA+) cells were 68.4 +/- 8.6% (group 1, less than 1 year old), 70.3 +/- 9.2% (group 2, 1 to 2 years old), 72.0 +/- 3.7% (group 3, 5 to 6 years old), and 63.8 +/- 10.1% (group 4, 10 to 11 years old). The mean percentages of SIg-positive (SIg+) cells in blood were 32.1 +/- 10.6% (group 1), 43.2 +/- 7.0% (group 2), 34.3 +/- 4.8% (group 3), and 35.0 +/- 6.8% (group 4). The mean total percentages of PNA+ and SIg+ cells were 100 +/- 6.0% (group 1), 113.5 +/- 4.9% (group 2), 106.3 +/- 5.3% (group 3), and 98.9 +/- 9.2% (group 4). The proportions of PNA+ and SIg+ cells in dogs of group 2 were significantly (P less than 0.05) different from those in dogs of the other groups. Serial changes in PNA+ and SIg+ cells were investigated in blood of 6- to 29-week-old pups (n = 8). A significant (P less than 0.05) transient decrease in PNA+ cells and a corresponding increase in SIg+ cells was observed in pups between 14 and 17 weeks old. Lymphoid tissue specimens and blood samples were obtained from 2- to 6-month-old dogs (n = 11) and from 6- to 12-month-old dogs (n = 10).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
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