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161.
The future of scientific journals. A computer-based system will enable a subscriber to receive a personalized stream of papers 总被引:1,自引:0,他引:1
Since many of the problems that beset readers, authors, and publishers of scientific journals are caused by the growth of science or by the frailties of human nature, we cannot hope for complete solutions. In an effort to make progress, within the framework of the possible, we propose that journals stop binding papers into issues and, instead, distribute to each subscriber a personalized stream of papers, abstracts, and titles. This type of distribution, which has been made possible by the advent of high-speed computers, would not affect the traditional roles of editors, referees, and libraries. We also propose that journals recognize the need for very rapid communication in certain fields, and meet the threat of public preprint-exchange systems in these fields by themselves publishing preprints in an appropriately limited manner. 相似文献
162.
Leukocyte alkaline phosphatase: electrophoretic variants associated with chronic myelogenous leukemia 总被引:1,自引:0,他引:1
Starch-gel electrophoresis of leukocyte alkaline phosphatases, rendered soluble by treating normal leukocytes with butanol, revealed three electrophoretic variants of the enzyme. The phosphatases in similarly prepared extracts of leukemia cells differed from the normal isozymes in electrophoretic. mobility. A single variant was detected in one case of untreated leukemia; a similar component and three additional ones were seen in leukemia treated with 6-mercaptopurine. 相似文献
163.
Tissue concentrations of nitrogen (N) and phosphorus (P) were measured in water hyssop (Bacopa monnieri) subjected to four progressive levels of flooding: well-drained Control, Intermittently Flooded, Partially Flooded, and Continuously Flooded. Soil redox potential (Eh), measured at two levels in the mesocosms decreased under flooding. Flooding increased biomass and decreased root growth and N and P concentrations in shoots, with the decreases being most pronounced in the Partially Flooded and Continuously Flooded treatments. The decreased uptake of N and P under flooding underscores the need to better understand how wetland plants function in nutrient-rich environments subjected to variable flooding. Additionally, the apparent decreased translocation of N and P from the root to the shoot in flooding conditions may be indicative of an overall decrease in mineral transport, which would have implications for the design and management of remediation systems. 相似文献
164.
Nitrate Toxicity to Five Species of Marine Fish 总被引:2,自引:0,他引:2
Richard H. Pierce Jason M. Weeks James M. Prappas 《Journal of the World Aquaculture Society》1993,24(1):105-107
165.
Remotely sensed mesoscale oceanography and the distribution of Illex argentinus in the South Atlantic 总被引:1,自引:0,他引:1
In this study, we consider the influence of mesoscale oceanographic processes around the Falkland Islands (Islas Malvinas) in the South-west Atlantic, during the period in which the commercial squid fishery for Illex argentinus operates. Spatially referenced fishery data and satellite-derived advanced very high resolution radiometry (AVHRR) sea surface temperature (SST) data were examined using geographic information system (GIS) techniques. The distribution and relative abundance of I. argentinus in the Falkland Islands fishery was examined for the period 1989–96. Three consistent areas of high abundance were observed to the north-east (shelf-break region) and north-west (shelf region) of the islands, and close to the northern coast of East Falkland. Areas of high sea surface temperature gradients (thermal gradients) extracted from remotely sensed satellite images were used as an indicator of mesoscale oceanographic activity and compared with the location of the fishery. I. argentinus were found to be associated with areas of thermal gradients, commonly seen at the interface of Falkland Current and Patagonian shelf waters. The techniques used in this analysis allow the overlay and analysis of physical oceanographic and fishery data with potential applications in fisheries management and operational fisheries oceanography. 相似文献
166.
- The short-beaked common dolphin is one of the most numerous cetacean species in the North-East Atlantic and plays a key functional role within the ecosystem as a top predator. However, in 2013, its conservation status for the European Marine Atlantic, under Article 17 of the Habitats Directive, was assessed as ‘Unfavourable-Inadequate’. Of key concern for this species is fishery bycatch, with pollution also being an issue. There are, however, major knowledge gaps concerning the extent of the effects of such pressures on the species.
- Implementation of national observer bycatch programmes and bycatch mitigation measures under EC Regulation 812/2004 has been important. The responsibility for this is currently being transferred to the EU fisheries Data Collection Framework and Technical Measures Framework, the potential advantages and disadvantages of which are discussed. Collection of data and samples through national stranding schemes in some countries has enabled assessments of life-history parameters, dietary requirements, and the effects of stressors such as pollutants.
- Nevertheless, in order to improve the conservation status of the North-East Atlantic population, a number of key actions are still required. These include the implementation of a species action plan, finalization of a management framework procedure for bycatch, and coordination between member states of monitoring programmes. It is important that there is monitoring of the state of the common dolphin population in the North-East Atlantic management unit through regular surveys spanning the range of the management unit, as well as continued assessment of the independent and interactive effects of multiple stressors. Above all, conservation status would be improved through application and enforcement of existing legislation in European waters.
- This paper provides a summary of the current state of our knowledge of common dolphins in the North-East Atlantic along with recommendations for conservation management that may also be relevant to the species in the Mediterranean Sea.
167.
Polarized and unpolarized neutron scattering was used to measure the wave vector- and frequency-dependent magnetic fluctuations in the normal state (from the superconducting transition temperature, Tc = 35 kelvin, up to 350 kelvin) of single crystals of La1.86Sr0.14CuO4. The peaks that dominate the fluctuations have amplitudes that decrease as T-2 and widths that increase in proportion to the thermal energy, kBT (where kB is Boltzmann's constant), and energy transfer added in quadrature. The nearly singular fluctuations are consistent with a nearby quantum critical point. 相似文献
168.
169.
Jeryl C. Jones Thomas J. Tucker Joshua C. Tan Bess J. Pierce Judy L. Foxworth Benjamin Long Tisha A.M. Harper Daniel Moreno 《Journal of Veterinary Behavior: Clinical Applications and Research》2013,8(5):309-315
An improved understanding of the early behavioral indicators of lumbosacral disease in working dogs may allow earlier interventions and help reduce premature retirement because of disability. However, recognition of early behavioral indicators can be challenging in stoic, high-drive working dogs because they often mask clinical signs. The purpose of this feasibility study was to develop a technique for visualizing canine skeletal movements during working tasks and to describe veterinary clinical specialist opinions on the utility of the visualization technique. Three detection-trained police dogs with a recent history of working task deficits and suspected lumbosacral disease were recruited for the study. Conventional and motion capture video recordings were acquired as dogs performed walking and search high working tasks. Whole-body computed tomography (CT) scans were acquired using clinical multislice CT scanners. Image data from motion capture recordings and whole-body CT scans were analyzed and merged. Three-dimensional (3D) computer animation video clips of skeletal movements were created for each dog and each task, using multiple viewing angle perspectives. Interactive meetings with veterinary clinical specialist reviewers were used to refine point placements for the final renderings. Veterinary clinical specialists reviewed final 3D animation movie clips and recorded their opinions on the utility for the visualization technique. Veterinary clinical specialists reported that the computer animations helped them recognize behavioral characteristics that they had not initially noticed in physical examinations. Potential applications for this visualization technique include creating educational training aids for veterinary students, owners, and handlers; assisting veterinarians in planning rehabilitative treatments; and assisting researchers in developing computer models for biomechanical analyses. Future controlled prospective studies are needed in a large number of normal and affected working dogs to improve accuracy of the visualization technique and test the effect of the technique on observer performance. 相似文献
170.
José L. Chávez Francis J. Pierce Todd V. Elliott Robert G. Evans 《Precision Agriculture》2010,11(1):1-10
Continuous move irrigation systems have been modified since the 1990s to support variable rate irrigation. Most of these systems
used PLC (Programmable Logic Controllers) technology that performed well for on-site control but were very expensive to add
remote, real-time monitoring and control aspects that have been made possible by wireless sensor networks and the Internet.
A new approach to the monitoring and control of continuous move irrigation systems is described. This system uses a Single
Board Computer (SBC) using the Linux operating system to control solenoids connected to individual or groups of nozzles based
on prescribed application maps. The main control box houses the SBC connected to a sensor network radio, a GPS (Global Positioning
System) unit, and an Ethernet radio creating a wireless connection to a remote server. A C-software control program resides
on the SBC to control the on/off time for each nozzle group using a “time on” application map developed remotely. The SBC
also interfaces with the sensor network radio to record measurements from sensors on the irrigation system and in the field
that monitor performance and soil and crop conditions. The SBC automatically populates a remote database on the server in
real time and provides software applications to monitor and control the irrigation system through the Internet. 相似文献