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   34419篇
  免费   2841篇
  国内免费   188篇
耳鼻咽喉   542篇
儿科学   832篇
妇产科学   606篇
基础医学   4229篇
口腔科学   835篇
临床医学   3228篇
内科学   7842篇
皮肤病学   337篇
神经病学   2923篇
特种医学   1305篇
外科学   5841篇
综合类   723篇
一般理论   24篇
预防医学   2650篇
眼科学   861篇
药学   2308篇
中国医学   78篇
肿瘤学   2284篇
  2023年   122篇
  2022年   196篇
  2021年   577篇
  2020年   326篇
  2019年   581篇
  2018年   680篇
  2017年   557篇
  2016年   545篇
  2015年   613篇
  2014年   1021篇
  2013年   1451篇
  2012年   2187篇
  2011年   2203篇
  2010年   1239篇
  2009年   1187篇
  2008年   2049篇
  2007年   2212篇
  2006年   2340篇
  2005年   2324篇
  2004年   2172篇
  2003年   2207篇
  2002年   2064篇
  2001年   399篇
  2000年   396篇
  1999年   458篇
  1998年   554篇
  1997年   435篇
  1996年   404篇
  1995年   332篇
  1994年   298篇
  1993年   272篇
  1992年   309篇
  1991年   286篇
  1990年   265篇
  1989年   263篇
  1988年   241篇
  1987年   219篇
  1986年   215篇
  1985年   212篇
  1984年   240篇
  1983年   205篇
  1982年   228篇
  1981年   220篇
  1980年   177篇
  1979年   148篇
  1978年   159篇
  1977年   146篇
  1976年   115篇
  1974年   122篇
  1973年   117篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
BACKGROUND: Acute rejection commonly occurs within the first year after heart transplantation, and then decreases in frequency with time. Recently, the long-term utility of endomyocardial biopsy during routine annual catheterization has been questioned. The purpose of this study was to retrospectively review the prevalence of biopsy-proven rejection during routine annual catheterization in our patient population, determine whether biopsies late after transplant are useful, and identify factors that correlate with late unsuspected rejection. METHODS: Biopsy results from the annual catheterization were evaluated from 1986 to August 2000. The prevalence of moderate rejection was evaluated and compared with the patient's immunosuppressive regimen; the prevalence of late rejection; and how late rejection correlated with recipient age, number of first-year rejections and presence of sub-therapeutic cyclosporine. RESULTS: A total of 1108 biopsies were performed in 269 children with a mean follow-up of 5 +/- 3 years (median 5 years, range 1 to 11 years). Three-drug immunosuppressive therapy, including steroids, was used in 93 patients. There was a persistent 8% to 10% prevalence of moderate rejection at up to 10 years post-transplantation. Moderate rejection was more likely in patients: (1). on 3-drug immunosuppressive therapy; (2). with a recipient age >1 year; and (3). with a relatively lower cyclosporine level. CONCLUSIONS: These data suggest that continued surveillance of pediatric transplant patients for acute rejection is indicated for long-term follow-up.  相似文献   
72.
Twenty adolescent male sexual offenders were evaluated by penile plethysmography on two separate occasions. Stimuli consisted of 19, two-minute audiotaped cues. Test-retest reliability was demonstrated for 15 of the 19 audiotaped vignettes. The highest correlations were found for those sexual behaviors in which the adolescents had engaged.  相似文献   
73.
Social competence assessment and training has long focused on specific skills within the clinical setting. In addition, emphasis has been placed on identifying deficits relative to an arbitrary, often idiosyncratic metric. In this article, we discuss the importance of the principles that underlie communication and which are reflected in the range of behaviours described as social competence . We review methods we have found productive in the training of these principles with persons who have suffered traumatic brain injuries.  相似文献   
74.
75.
We performed proton magnetic resonance spectroscopic imaging of the temporal lobes between, during, and soon after nonconvulsive seizures in 20 patients with documented temporal lobe epilepsy, 5 patients with primary generalized epilepsy, and 2 patients with secondary generalized epilepsy. Our objective was to determine whether there were metabolic changes observable by magnetic resonance spectroscopic imaging during seizures and whether these changes were specific for focal or generalized nonconvulsive seizures. We found a significant increase in lactate to creatine plus phosphocreatine (lactate/creatine) values, reflecting an imbalance in energy supply and demand or an adaptation in response to ictal neuronal discharges, during and soon after complex partial seizures, but not during or soon after absence seizures associated with generalized epilepsy. In patients with temporal lobe epilepsy, the N-acetylaspartate resonance relative to creatine plus phosphocreatine was low in one or both temporal lobes, indicating neuronal loss or damage. This was not observed in patients with primary generalized epilepsy. The regions with abnormal lactate/creatine and N-acetylaspartate/creatine values corresponded to the epileptogenic focus as defined by clinical-electroencephalographic investigation. There was no change in the N-acetylaspartate/creatine values in the temporal lobes between the interictal, ictal, or postictal states. We conclude that (1) partial seizures are associated with abnormally high lactate levels, but absence seizures are not, and (2) no short-term changes of N-acetylaspartate occur during or soon after complex partial seizures or absence seizures. These findings may be related to the lack of postictal confusion in patients with absence seizures, as well as with the more benign course of primary generalized epilepsy with nonconvulsive attacks.  相似文献   
76.
Thyroid dysfunction is a well-known contributor to psychiatric morbidity. To investigate the mechanism(s) by which thyroid hormone availability affects cerebral activity, a group of thyroidectomized individuals were studied at two points in time: when markedly hypothyroid in preparation for a thyroid cancer metastatic survey and when clinically and/or biochemically euthyroid. The analysis consisted of single photon emission computed tomography (SPECT) using a lipophilic radiopharmaceutical, technetium-99m (Tc-99m) ethyl cysteinate dimer (ECD), and measurement of mood, anxiety, and psychomotor function, at both points in time. Both increases and decreases in regional cerebral radiotracer activity were found in the hypothyroid condition relative to the euthyroid condition, and the neuropsychological assessment demonstrated significantly greater depression, anxiety, and psychomotor slowing during the hypothyroid state. Increased radiotracer activity was seen in frontal and temporal regions, posterior cingulate gyrus, thalamus, and putamen. Decreased activity was seen in the occipital cortex, and the pre- and postcentral gyri. This distribution pattern is partially consistent with findings in persons with depression and anxiety unrelated to thyroid disease, supporting the link between the symptoms observed in our subjects and their marked hypothyroidism. Finally, these results support the need to consider the effect of the thyroid state on cellular mechanisms of uptake and retention of cerebral blood flow radiopharmaceuticals when studying 'noneuthyroid' individuals.  相似文献   
77.
78.
79.
Corticosteroid Supplementation for Adrenal Insufficiency   总被引:2,自引:0,他引:2  
Coursin  Douglas B.; Wood  Kenneth E. 《JAMA》2002,287(2):236-240
  相似文献   
80.
Interleukin–2 and hyperthermia have been used individually to treat a variety of tumors in both experimental and human trials. Combined adoptive immunotherapy and hyperthermia is an exciting new line of investigation. Previous work in our laboratory has shown that combined local hyperthermia and rIL-2 therapy can significantly decrease the rate of tumor growth. In this study, we investigated the effect of combined whole-body hyperthermia (WBHT) and rIL-2 on the growth of subcutaneous MCA-105 murine tumors in C57BL/6 mice. Treatment of both microscopic (day 3) and macroscopic (day 10) tumors was evaluated. In the treatment of microscopic tumors, animals received either no treatment; rIL-2 (3 × 105 IU ip tid) on days 3–7; plus WBHT(41°C for 30 min) on days 3, 5, and 7; or WBHT only on days 3, 5, and 7. In treating macroscopic tumors, animals received either no treatment; rIL-2 on days 10–14; plus WBHT on days 10, 12, and 14; or WBHT only on days 10, 12, and 14. While combined treatment and WBHT alone had no significant effect on the growth of microscopic tumors, combined IL-2 and WBHT significantly reduced the rate of tumor growth of macroscopic tumors. These results suggest that the tumor microenvironment plays a critical role in combined WBHT and rIL-2 therapy, and may be due to effects of WBHT on the tumor vasculature. © 1993 Wiley-Liss, Inc.  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