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991.
In order to improve removal for nitrogen in a pilot-scale submerged membrane bioreactor (SMBR), intermittent aeration was
conducted, and the effect on the treatment performance under four kinds of operation condition (run 1, continuous aeration;
run 2, 60/60 min aeration on/off time; run 3, 60/90 min aeration on/off time; run 4, 60/75 min aeration on/off time) was evaluated.
The results showed that depending on the specific on/off of the aeration time ratio, removal efficiency of nitrogen could
be improved significantly, and the removal rates of total nitrogen (TN) under different operation conditions were 28.0%, 59.5%,
66.8% and 70.7%, respectively. There were no obvious differences for removal rates for CODCr and ammonia among different operation conditions. In general, intermittent aeration could be used as a feasible way to improve
treatment performance for nitrogen in the SMBR. 相似文献
992.
Viability criteria for differential inclusions 总被引:2,自引:0,他引:2
Yan Gao 《系统科学与复杂性》2011,24(5):825-834
A method of verifying the viability criterion at a given point for a region with nonsmooth boundary, which is expressed by
a quasidifferentiabl function, under a differential inclusion which is a convex hull of finitely many functions, is proposed.
By this method, determining the viability is transformed into solving a number of systems of linear inequalities, or equivalently
solving a number of linear programming problems. For the other differential inclusion, called the generalized convex process,
it is shown that viability condition holds for a polytope if and only if it holds at all of its vertices. This result is an
extension of corresponding one for a linear control system. 相似文献
993.
The state transfer under control fields is analyzed based on the Bloch sphere representation of a single qubit. In order to
achieve the target from an arbitrary initial state to a target state, the conditions that parameters should satisfy are deduced
separately in two different requirements: One is in the case of the rotation angle around the x-axis being fixed and another is in the situation with a given evolution time. Several typical states trajectories are demonstrated
by numerical simulations on the Bloch sphere. The relations between parameters and the trajectories are analyzed. 相似文献
994.
A rapid process of hybridisation of man and technology, organisation and technology and society and technology is currently
sweeping the world. This process requires a way of (scientific) thinking that takes hybrid systems as the starting point.
Such an approach makes it increasingly important for hybrid systems to be interlinked, enabling them to exchange and share
information through these links. This linking of (hybrid) systems to enable them to exchange and share information can also
be denoted as the realisation of interoperability between (hybrid) systems. Five principles from Luhmann’s systems theory
can help us understand interoperability. Interoperability enables (hybrid) systems to join random coalitions and networks.
The network centric warfare concept is currently the basis for international efforts aimed at the development and application
of interoperability that would enable armed forces to act effectively and efficiently. This paper demonstrates what we can
learn from Luhmann’s system’s theory. 相似文献
995.
Vegetation effects on mean daily maximum and minimum surface air temperatures over China 总被引:5,自引:0,他引:5
Changes in the daily maximum (Tmax) and minimum (Tmin) surface air temperatures and the associated temperature extremes have severe consequences on human society and the natural environment. In this study, we assess vegetation effects on mean Tmax and Tmin over China by computing a vegetation feedback parameter using the satellite-sensed Normalized Difference Vegetation Index (NDVI) and observed temperatures for the period 1982–2002. In all seasons, vegetation exerts a much stronger forcing on Tmax than on Tmin, and thus has a substantial effect on the diurnal temperature range (DTR) over China. Significant positive feedbacks on Tmax and the DTR occupy many areas of China with the feedback parameters exceeding 1°C (0.1 NDVI)–1, while significant negative effects only appear over the summertime climatic and ecological transition zone of northern China and some other isolated areas. Also, the vegetation feedbacks are found to vary with season. In areas where significant feedbacks occur, vegetation contributes to typically 10%–30% of the total variances in Tmax, Tmin, and the DTR. These findings suggest that vegetation memory offers the potential for improving monthly-to-seasonal forecasting of Tmax and Tmin, and the associated temperature extremes over China. Meanwhile, the limitations and uncertainties of the study should be recognized. 相似文献
996.
<正> Carvalho,Lucchesi and Murty proved that any 1-extendable graph G different from K_2and C_(2n)has at least Δ(G)edge-disjoint removable ears,and any brick G distinct from K_4 and■hasat least Δ(G)-2 removable edges,where Δ(G)denotes the maximum degree of G.In this paper,weimprove the lower bounds for numbers of removable ears and removable edges of 1-extendable graphs.It is proved that any 1-extendable graph G different from K_2 and C_(2n)has at least χ′(G)edge-disjointremovable ears,and any brick G distinct from K_4 and■has at least χ′(G)-2 removable edges,whereχ′(G)denotes the edge-chromatic number of G. 相似文献
997.
Sara Lise Jeppesen 《Systemic Practice and Action Research》2011,24(2):133-146
The aim of this paper is to explore an explicit use of the concept of sustainability within transport planning. This paper
analyses the concept of sustainability based on a practical approach for a sustainable development of Nordhavn, an area of
Copenhagen, exemplifying a complex planning problem. An exploration of the application of the concept of sustainability is
carried out using elements of Soft Systems Methodology (SSM). This approach indicates a need to separate the use of sustainability
considerations regarding the transport planning ‘process’ from the transport planning ‘results’. The two approaches are related
to the planning levels presented by Ulrich (Syst Prac 1(4):415–428, 1988). It was chosen to focus on the understanding of a sustainable transport planning process. This focus is addressed by four
stakeholder groups interviewed based on the ‘ought to’ mode of Critical Systems Heuristics (CSH). Finally an outline of some
of the factors of a sustainable transport planning process is proposed. 相似文献
998.
The CLC protocol (proposed by Tzung-Her Chen, Wei-Bin Lee and Hsing-Bai Chen, CLC, for short) is a new three-party password-authenticated
key exchange (3PAKE) protocol. This CLC protocol provides a superior round efficiency (only three rounds), and its resources
required for computation are relatively few. However, we find that the leakage of values A
V
and B
V
in the CLC protocol will make a man-in-the-middle attack feasible in practice, where A
V
and B
V
are the authentication information chosen by the server for the participants A and B. In this paper, we describe our attack on the CLC protocol and further present a modified 3PAKE protocol, which is essentially
an improved CLC protocol. Our protocol can resist attacks available, including man-in-the-middle attack we mount on the initial
CLC protocol. Meanwhile, we allow that the participants choose their own passwords by themselves, thus avoiding the danger
that the server is controlled in the initialization phase. Also, the computational cost of our protocol is lower than that
of the CLC protocol. 相似文献
999.
Our world has been changing at an exponential rate.As a result of this rapid growth,we will be forced to make changes in not only the way we live in the environment but also in the environment itself such as designing the cities of the future to be in greater harmony with the increasing population and growing complexity.The paper contains both reflections on global awareness and comprehensive criteria and their priorities for choosing the most desirable city. 相似文献
1000.
In this paper,domain decomposition method(DDM) for numerical solutions of mathematical physics equations is improved into dynamic domain decomposition method(DDDM) . The main feature of the DDDM is that the number,shape and volume of the sub-domains are all flexibly changeable during the iterations,so it suits well to be implemented on a reconfigurable parallel computing system. Convergence analysis of the DDDM is given,while an application approach to a weak nonlinear elliptic boundary value problem and a ... 相似文献