首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2305篇
  免费   93篇
  2023年   16篇
  2022年   16篇
  2021年   23篇
  2020年   44篇
  2019年   57篇
  2018年   83篇
  2017年   67篇
  2016年   75篇
  2015年   44篇
  2014年   66篇
  2013年   331篇
  2012年   105篇
  2011年   101篇
  2010年   67篇
  2009年   65篇
  2008年   72篇
  2007年   89篇
  2006年   87篇
  2005年   69篇
  2004年   79篇
  2003年   81篇
  2002年   68篇
  2001年   29篇
  2000年   43篇
  1999年   30篇
  1998年   33篇
  1997年   34篇
  1996年   25篇
  1995年   19篇
  1994年   22篇
  1993年   29篇
  1992年   24篇
  1991年   19篇
  1990年   16篇
  1989年   16篇
  1988年   15篇
  1987年   30篇
  1986年   11篇
  1985年   35篇
  1984年   23篇
  1983年   14篇
  1982年   19篇
  1981年   24篇
  1980年   26篇
  1979年   11篇
  1978年   13篇
  1976年   17篇
  1975年   12篇
  1974年   13篇
  1967年   9篇
排序方式: 共有2398条查询结果,搜索用时 15 毫秒
71.
Cancer is a group of diseases that are complicated by various treatment choices available. Information exchange between a patient and physician is critical in helping people to understand what is happening to them and what options for therapy are recommended and available. When information is not exchanged, information control by one or both of the participants occurs. Information needs to be taken into account by both health care professional and patients in making decisions during the crucial phases of care. The phases of care presented are a diagnosis, treatment, the decision, and a recurrence. Factors that influence effective information exchange among patient-provider systems are discussed.  相似文献   
72.
Statistical significance tests are derived and evaluated for measuring apparent differences between an obtained and an expected binormal ROC curve, between two independent binormal ROC curves, and among groups of independent binormal ROC curves. A binormal ROC curve is described by two parameters which represent the spread of the means and the ratio of the standard deviations of the two underlying Gaussian decision variable distributions. To test the significance of apparent differences between or among ROC curves, approximate χ2 statistics for each of the three tests were constructed from maximum likelihood estimates of the two parameters defining the binormal ROC curve. The performance of each test statistic was evaluated by simulating five-category rating scale data with equal numbers of noise and signal-plus-noise trials (set at 50, 250, and 500) for each of three typical ROC curves. For the significance test involving only one ROC curve, rating scale data were generated from the chance diagonal of the ROC space also. Although test performance was found to be somewhat dependent on the number of trials and on the location of the ROC curve in the ROC space, comparisons of the obtained and expected fractions of (falsely) significant results at various α levels showed the proposed statistical significance tests to be reliable under practical experimental conditions.  相似文献   
73.
An Ames (1951, Psychological Monographs, 65(1, Whole No. 324)) static trapezoidal window, under monocular view, was used to test young infants' responsiveness to pictorial depth. When adults view this display monocularly with the smaller side of the window rotated toward them, they report that the orientation of the display becomes ambiguous: When the head is moved, the window may appear to be in the fronto-parallel plane or either side may appear closer. The 7-month-olds we tested appeared to experience a similar ambiguity; they reached to the near side of the rotated trapezoidal window with significantly less consistency or directedness than infants in a control group tested with a rotated object that lacked pictorial depth information. When 5-month-olds were tested, however, they reached with equal consistency to the closer side of the trapezoidal window and of the control display, apparently uninfluenced by the pictorial depth information available in the trapezoidal window. Thus, sensitivity to the pictorial information for depth that is present in the trapezoidal window appears to develop after the age of 22 weeks.  相似文献   
74.
The experiment tested a prediction, derived from the lexicalist model of grammar (J. Bresnan 1978, in M. Halle, J. Bresnan, & G. A. Miller (Eds.), Linguistic theory and psychological reality, Cambridge, Mass.: MIT Press, pp. 1–59), that difficulty in accessing a verb from the lexicon should impair the generation of the associated to-complement clause while not significantly affecting the generation of word-independent constructions such as questions. Four aphasic subjects with word-finding difficulties but relatively high BDAE ratings on grammatical ability were examined. A modified story completion paradigm was used to elicit the favored constructions. Consistent with the hypothesis, all subjects showed greater difficulty in generating to-complements.  相似文献   
75.
This study examined the location and rate of stuttering in the spontaneous speech of nine young stutterers (4.0–6.6 yr) in relation to certain aspects of syntax. It was designed to answer the following questions: Is there more stuttering at clause onset (boundary) than at other points in the clause? Does the type of clause influence rate of stuttering? Is there more stuttering on complex than on simple sentences? The syntactic analysis defined 10 clause types (seven pertaining to complex sentences and three pertaining to simple sentences); clause boundaries (taking into account “filler” words occuring in such positions); and hierarchical constituent structure within sentences. Stuttering was found with significantly greater frequency at clause boundaries than at internal (nonboundary) positions of clauses. This was apparent for nine of the 10 clause types, the exception being complement clauses. The word “and” at the beginning of simple and complex sentences provoked a high rate of stuttering. The hierarchical structure within the clause did not influence the location of stuttering, and sentence complexity was not a factor in the rate of stuttering.  相似文献   
76.
Following Eysenck (1967), Gray (1973) and Wakefield (1979), it was hypothesized that the arithmetic achievement of extraverts would be better than introverts in those classrooms in which teacher-presented rewards predominated, and the arithmetic achievement of introverts would be better than extraverts in those classrooms in which teacher-presented punishment predominated. Five classrooms were rank-ordered according to their ratios of teacher-presented reward to teacher-presented punishment. A total of 101 fourth and fifth grade students from the five classrooms were then administered the Junior Eysenck Personality Questionnaire (JEPQ) and an arithmetic pretest. Subsequent to 40 school days, the students were administered the arithmetic posttest. Partialling out arithmetic pretest scores, lie scale scores from the JEPQ, and total arithmetic raw scores from the Comprehensive Test of Basic Skills (CTBS), regression analysis of arithmetic posttest scores with the interaction of extraversion scores from the JEPQ and classroom rank-order of the ratio of teacher-presented reward to teacher-presented punishment yielded significant results supporting the hypothesis. Additional analysis indicated the presence of non-hypothesized interactions of the Psychoticism and Neuroticism scales of the JEPQ with reward-punishment and extraversion.  相似文献   
77.
Forty-eight pregnant adolescents who applied for therapeutic abortions (TAs) were compared with 55 adolescents who planned to have their babies (Terms) and 67 adolescents who were not pregnant (Controls) on the California Psychological Inventory (CPI). All the subjects were single, Black, and aged 15 or 16. CPI results point to psychological differences with the Controls being most socialized, followed by the TAs, and then the Terms. Term girls seem to be experiencing a void and appear to be trying to fill it and assume an adult role by having a baby; the TAs do not seem to have these same needs. In addition, girls who became pregnant and described the relationship with the putative father as casual, appear on the CPI to have more daily problems, lack socialization, be less clear thinking, and have poor self-control. Pregnant girls who have good communication with their mothers showed no differences on the CPI from girls with poor communication with their mothers.  相似文献   
78.
79.
A method for identifying eggs laid by different subsections or individual members of groups of domestic hens is described. Fat-soluble dyes are placed in gelatin capsules and fed to selected birds. These dyes produce discrete colored bands in the yolks of eggs laid by those birds. The presence of dye in eggs can be detected through the shell, and different patterns of rings can be distinguished by boiling and sectioning eggs. Application of the method to other species and other circumstances is considered.  相似文献   
80.
In a factorial design with two or more factors, there is nonzero interaction when the differences among the levels of one factor vary with levels of other factors. The interaction is disordinal or qualitative with respect to a specific factor, sayA, if the difference between at least two levels ofA is positive for some and negative for some levels of the other factors. Using standard methods of analysis, there is a potentially large probability of drawing incorrect conclusions about the signs of differences in the presence of disordinal interaction. The maximum probability of such incorrect conclusions, or directional errors, is derived for two-factor designs in which the factor of interest has two levels and the number of levels of the other factor varies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号