全文获取类型
收费全文 | 37290篇 |
免费 | 1340篇 |
国内免费 | 18篇 |
专业分类
38648篇 |
出版年
2020年 | 443篇 |
2019年 | 491篇 |
2018年 | 619篇 |
2017年 | 634篇 |
2016年 | 738篇 |
2015年 | 540篇 |
2014年 | 646篇 |
2013年 | 3087篇 |
2012年 | 1160篇 |
2011年 | 1166篇 |
2010年 | 793篇 |
2009年 | 816篇 |
2008年 | 1150篇 |
2007年 | 1069篇 |
2006年 | 967篇 |
2005年 | 887篇 |
2004年 | 889篇 |
2003年 | 856篇 |
2002年 | 858篇 |
2001年 | 850篇 |
2000年 | 871篇 |
1999年 | 641篇 |
1998年 | 422篇 |
1997年 | 378篇 |
1992年 | 586篇 |
1991年 | 558篇 |
1990年 | 570篇 |
1989年 | 558篇 |
1988年 | 518篇 |
1987年 | 526篇 |
1986年 | 538篇 |
1985年 | 584篇 |
1984年 | 521篇 |
1983年 | 465篇 |
1982年 | 375篇 |
1981年 | 421篇 |
1979年 | 540篇 |
1978年 | 427篇 |
1977年 | 372篇 |
1976年 | 365篇 |
1975年 | 475篇 |
1974年 | 532篇 |
1973年 | 542篇 |
1972年 | 447篇 |
1971年 | 445篇 |
1970年 | 395篇 |
1969年 | 417篇 |
1968年 | 512篇 |
1967年 | 490篇 |
1966年 | 459篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
Benzodiazepine receptor ligand influences on acquisition: suggestion of an endogenous modulatory mechanism mediated by benzodiazepine receptors 总被引:2,自引:0,他引:2
In rats, pretraining ip administration of the central benzodiazepine receptor antagonist, flumazenil (5.0 mg/kg), or of the inverse agonist, n-butyl-beta-carboline-3-carboxylate (BCCB) (0.2 or 0.5 mg/kg), facilitated retention of a step-down inhibitory avoidance task; the central agonists, clonazepam and diazepam (0.4 or 1.0 mg/kg), had an opposite effect, and the peripheral agonist, 4'-chlordiazepam (1.25 or 6.25 mg/kg), was without effect. Pre- but not post-training flumazenil (2.0 mg/kg) blocked the effect of BCCB (0.5 mg/kg), clonazepam (1.0 mg/kg), or diazepam (1.0 mg/kg) given also pretraining. The post-training administration of all of these drugs had no effect on retention of the avoidance task. Flumazenil (5.0 mg/kg) and BCCB (0.5 mg/kg), given before training, enhanced retention test performance of habituation to a buzzer but not of habituation to an open field. In the three tasks studied, none of the drugs used had any appreciable effect on training session parameters. These results suggest that there is an endogenous mechanism mediated by benzodiazepine agonists, sensitive to inverse agonists, that normally down-regulates acquisition of certain behaviors; this mechanism becomes activated only when the tasks involve or occur with a certain degree of stress or anxiety (i.e., inhibitory avoidance or habituation to the buzzer) and not in less stressful or anxiogenic tasks (i.e., habituation to an open field). 相似文献
922.
Research in marital therapy has been disadvantaged by the lack of a good, short and recent psychometric questionnaire to objectively assess the state of a marriage for research, demographic and clinical purposes. The Golombok Rust Inventory of Marital State (GRIMS) is a companion questionnaire to the Golombok Rust Inventory of Sexual Satisfaction (GRISS), and concentrates on aspects other than the sexual in a dyadic relationship between two adults living together. It is a 28 item psychometrically constructed inventory designed to produce a single scale along which changes in a marriage may develop as marital therapy progresses. It has been shown to be valid for this purpose, and to have a good reliability. 相似文献
923.
This report reviews the literature on the values of alcoholics and addicts in treatment and presents data that suggest a shift in values is involved in recovery from alcoholism through participation in Alcoholics Anonymous and that values clarification and value therapy may be useful in chemical dependency treatment. 相似文献
924.
James M. Dabbs Jr Charles H. Hopper Gregory J. Jurkovic 《Personality and individual differences》1990,11(12)
Relationships of serum and saliva to personality were examined among 401 college students in four laboratory studies and 5,236 military veterans in one archival study. Among the students, there were few relationships between testosterone and traditional personality measures. Among the veterans, MMPI scores and DSM-III diagnoses showed testosterone related to drug and alcohol abuse, antisocial and generally intemperate behavior, and effective disorders. Consistent with social control theory, correlations were higher among veterans who were lower in socioeconomic status. It appears likely that testosterone has innate effects that are socially undesirable but can be attenuated by bonds between the individual and society. Effect sizes were small, suggesting that testosterone will have noticeable effects only in large populations or individuals who differ markedly from the population mean. Further research should focus upon antisocial correlates of testosterone and conditions that produce marked changes in testosterone levels. 相似文献
925.
Michael J. Almeida 《Erkenntnis》1990,33(1):57-71
Standard dyadic deontic logic (as well as standard deontic logic) has recently come under attack by moral philosophers who maintain that the axioms of standard dyadic deontic logic are biased against moral theories which generate moral conflicts. Since moral theories which generate conflicts are at least logically tenable, it is argued, standard dyadic deontic logic should be modified so that the set of logically possible moral theories includes those which generate such conflicts. I argue that (1) there are only certain types of moral conflicts which are interesting, and which have worried moral theorists, (2) the modification of standard dyadic deontic logic along the lines suggested by those who defend the possibility of moral conflicts makes possible only uninteresting types of moral conflicts, and (3) the general strategy of piecemeal modification standard dyadic deontic logic is misguided: the possibility of interesting moral conflicts cannot be achieved in that way. 相似文献
926.
D. H. Mellor 《国际科学哲学研究》1990,4(2):159-170
The paper develops a unified account of both deterministic and indeterministic laws of nature which inherits the merits but not the defects of the best existing accounts. As in Armstrong's account, laws are embodied in facts about universals; but not in higher‐order relations between them, and the necessity of laws is not primitive but results from their containing chances of 0 or 1. As in the Ramsey‐Lewis account, law statements would be the general axioms and theorems of the simplest deductive theory of everything; but because laws are not so defined, simplicity of statement is not a criterion of law‐hood. 相似文献
927.
Efficacy of behavioral management and patient education on vascular access cleansing compliance in hemodialysis patients 总被引:1,自引:0,他引:1
Compared four treatment conditions to test their ability to enhance compliance with vascular access cleansing (VAC) procedures in a group of 56 hemodialysis patients. The conditions were patient education, behavioral management with monetary incentive, patient education/behavioral management, and attention control. Behavioral observers rated VAC behavior at pretreatment, posttreatment 1-month follow-up, and 1-year follow-up. Knowledge of VAC procedures was also assessed via a questionnaire at pretreatment and posttreatment. Data were analyzed using repeated-measures multivariate analyses of variance. Results indicated that the patients in the education/behavioral, behavioral, and education groups gave significantly more correct answers on our VAC knowledge questionnaires at posttreatment than did patients in the attention control group. Further, patients in the education/behavioral and behavioral groups completed significantly more VAC steps at posttreatment and 1-month follow-up than did patients in the education group and in the attention control group. Differences were not maintained at 1-year follow-up, although more than 50% of the patients were lost to follow-up. Implications of the present findings for behavioral and educational interventions are discussed. 相似文献
928.
Summary When a line (the pointer) is collinear with a dot, the addition of a second line (the induction line) contiguous with the dot or near it may cause the pointer to appear to be collinear with a point further along or nearer to the induction line. The geometrical relations upon which this effect, which we call attraction-caused misalignment, depends have been studied with the Obonai and Wundt-Loeb (Hotopf, 1981; Hotopf & Brown, 1988) figures. Drawing upon the studies of misalignment in the Morinaga figure carried out by Restle (1976), Day, Bellamy, and Norman (1983), and Day and Kasperczyk (1985), as well as upon two new experiments, we show that misalignment in the Morinaga figure is also attraction-caused misalignment, as previously defined. We conclude with a discussion of a number of theories that aim at accounting for attraction misalignment. 相似文献
929.
Summary In the literature two different views with regard to the time course of activation of recognition units —hypothetical entities that represent identity information —are proposed. Both views are derived from a restricted set of phenomena in visual perception. The first view gets its intuitions from phenomena such as those summarized by Bloch's law; these phenomena show integration or summation of activation over time. This grow-and-grow view assumes that recognition units accumulate activation gradually over times The second view finds its inspiration in phenomena such as Mach-bands and simultaneous contrast; these phenomena show inhibition or steady-state suppression over time. This grow-and-shrink view assumes that the activation levels increase fast initially and then start to decrease.The perception literature strongly suggests that it may be light intensity that determines whether mainly integration (and phenomena such as Bloch's law) or inhibition (and phenomena such as Mach-bands) is obtained. So it is also likely that both information-processing views apply only to a limited range of intensity conditions; the grow-and-grow view to conditions of low-flight intensities, and the grow-and-shrink view to conditions of intermediate-and high-light intensities.It is argued that, to arrive at a complete view, a visual phenomenon that applies to the complete range of light intensities should be taken as a background for generating hypotheses about time courses in visual-information processing. The Broca-Sulzer effect is such a phenomenon. Starting from this phenomenon a simple, synthesizing, information-processing model is derived that is compatible with both the grow-and-grow view and the grow-andshrink view. It is shown that, besides the relevant temporal properties, this model also produces the appropriate spatial properties. 相似文献
930.
The study was part of an official project of the Women in Management Division of the Academy of Management to examine the status of research in gender issues in organizations. It specifically looked at 22 major scholarly and trade journals plus the Proceedings of the Academy of Management for the six-year period of 1983–1988 to determine quantity, patterns, and trends in publication of research on issues of interest to the domain of the division. Results show a downward trend in gender-issue publication at a time when working women are becoming an ever-increasing percentage of the work force. This is particularly true of the so-called prestige journals. Psychology journals accounted for 64% of the total, management 13.4%, personnel 19%, and Proceedings 3.5%. Implications for research and careers are discussed.A shorter, less-complete version of this paper was presented in summary form at the annual meeting of The Academy of Management in Washington, DC, August 1989 as part of a symposium for the Women in Management Division. 相似文献