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   1351篇
  免费   103篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   94篇
妇产科学   9篇
基础医学   185篇
口腔科学   27篇
临床医学   107篇
内科学   352篇
皮肤病学   28篇
神经病学   194篇
特种医学   16篇
外科学   162篇
综合类   3篇
预防医学   33篇
眼科学   21篇
药学   173篇
肿瘤学   47篇
  2022年   11篇
  2021年   27篇
  2020年   15篇
  2019年   21篇
  2018年   34篇
  2017年   13篇
  2016年   27篇
  2015年   29篇
  2014年   37篇
  2013年   43篇
  2012年   59篇
  2011年   51篇
  2010年   35篇
  2009年   40篇
  2008年   60篇
  2007年   57篇
  2006年   70篇
  2005年   63篇
  2004年   51篇
  2003年   46篇
  2002年   67篇
  2001年   47篇
  2000年   34篇
  1999年   44篇
  1998年   20篇
  1997年   14篇
  1996年   13篇
  1995年   15篇
  1994年   10篇
  1993年   13篇
  1992年   29篇
  1991年   19篇
  1990年   28篇
  1989年   37篇
  1988年   29篇
  1987年   26篇
  1986年   23篇
  1985年   19篇
  1984年   15篇
  1983年   12篇
  1982年   10篇
  1981年   10篇
  1979年   12篇
  1978年   10篇
  1977年   10篇
  1975年   9篇
  1974年   14篇
  1973年   13篇
  1969年   9篇
  1968年   9篇
排序方式: 共有1455条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
The present survey assessed consumer satisfaction of patients having undergone psychotherapy for depression as well as service characteristics including treatment access, communication of diagnosis and treatment rationale, quality assurance and adverse events. The study was conducted in the form of a 15‐item questionnaire that was published in one of Germany's leading health magazines. 473 persons responded (81.5% women, age range 17–83). 49.8% of the respondents reported substantial or reasonable improvement; two out of three patients stated they had been satisfied with their therapy. Improvement and satisfaction were greater in those patients who had been informed about diagnosis and treatment; they were lower when unpleasant experiences were reported. Methodological restrictions of the study are outlined and hypotheses about potential strengths and deficits in the delivery of psychotherapy for depression in Germany are proposed. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
5.
6.
The binding characteristics of [3H]ketanserin (a reported selective radioligand for serotonin 5-HT2 receptors) and [125I]BE 2254 (which labels selectively alpha 1-adrenoceptors) were characterized in brain frontal cortex membranes of pig and man. Saturation experiments indicated that both radioligands label apparently a homogeneous class of binding sites in human and pig fontal cortex membranes. Competition experiments with [125I]BE 2254 using 17 agonists and antagonists showed monophasic and steep curves in human and pig frontal cortex membranes. The pharmacological profile of these sites is typical of alpha 1-adrenoceptors. In competition experiments with [3H]ketanserin, most of the tested compounds displayed shallow or biphasic curves. In particular, alpha 1-adrenoceptor-selective antagonists (prazosin, WB 4101, BE 2254...) displaced with nanomolar affinity about 15 and 40% of the specific [3H]ketanserin binding in human and pig frontal cortex membranes, respectively. The minor component of [3H]ketanserin binding correlated highly significantly with [125I]BE 2254 binding in both membrane preparations. The major component of [3H]ketanserin binding to pig and human frontal cortex membranes correlated significantly with [3H]ketanserin binding in rat brain cortex membranes (which is essentially to 5-HT2 receptors). The present data demonstrate that [3H]ketanserin in nanomolar concentrations binds significantly to alpha 1-adrenoceptors in human and pig frontal cortex membranes; this suggests a rather limited degree of selectivity of ketanserin for 5-HT2 receptors in pig and human tissues.  相似文献   
7.
8.
This study extended aspects of Biederman's (1987) recognition-by-components (RBC) theory to the analysis of age differences in the recognition of incomplete visually-presented objects. RBC theory predicts that objects are recognizable or recoverable under conditions of fragmentation if a sufficient amount of essential structural information remains available. Objects are rendered nonrecoverable by the omission or obstruction of essential structural features at vertices and areas of concavity. Fifteen young adults and 15 older adults participated in a study of the effects of amount (25%, 45%, 65%) and type of fragmentation (recoverable, nonrecoverable) on object naming. Age-related declines in recognizing incomplete objects were associated with the amount of fragmentation, but type of fragmentation did not affect the performance of older adults. For the young adults, accuracy of performance was affected by both amount and type of fragmentation, consistent with Biederman's RBC theory. These results were interpreted as suggesting that age-related declines in perceptual closure performance have to do with non-structural factors such as the ability to inferentially augment degraded or missing visual information.  相似文献   
9.
The production of chlamydospores is a diagnostic tool used to identify Candida albicans; these structures also represent a model for morphogenetic research. The time required to produce them with standard methods is 48-72 hours in rice meal agar and tensoactive agents. This time can be shorted using liquid media such as cornmeal broth (CMB) and dairy supplements. Five media were tested: CMB plus 1% Tween-80, CMB plus 5% milk, CMB plus 5% milk serum, milk serum, and milk serum plus 1% Tween-80, under different incubation conditions: at 28 degrees C and 37 degrees C in a metabolic bath stirring at 150 rpm, and at 28 degrees C in a culture stove. The reading time points were established at 8 and 16 hours. The best results were obtained at 16 hours with CMB plus 5% milk under incubation at 28 degrees C and stirring at 150 rpm. The next most efficient methods were CMB plus 5% milk serum and CMB plus 1% Tween-80, under the same incubation conditions. The other media were ineffective in producing chlamydospores. The absence of stirring at 28 degrees C prevented the formation of chlamydospores within the set time points, and incubation at 37 degrees C decreased their production. This paper reports that the time to form C. albicans chlamydospores can be reduced.  相似文献   
10.
The brains of 6 rats aged 12 months (adult) and 6 rats aged 24 months (aged) were embedded in paraffin following steady state perfusion with fixation solution. Glycosaminoglycans (GAGs) were demonstrated by histochemical methods using the Alcian blue CEC method in combination with the Feulgen reaction and testis hyaluronidase. Cell nuclei revealed different patterns of GAGs in different layers of the brain cortex and in different cell types. In neuronal cell nuclei of layer 2, no GAGs are found and this may be the case also in certain types of pyramidal cells. There was a reduction of the blue staining components of the chromatin network by hyaluronidase, and also a reduction of the electronmicroscopic contrast by this enzyme in pilot study using a specimen of one animal. The enzyme effects were found to be more marked or even exclusively present in the group of aged animals. Thus, the contents of chrondroitin sulfates or hyluronate which are substrates of the enzyme may be increased either relatively or absolutely in cell nuclei of aged brains whereas GAGs resistant to the enzyme may be reduced in activity. Since GAGs are known to influence DNA activity, the variations demonstrated may be assumed to be of significance for the aging process in postmitotic cells.  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