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   125323篇
  免费   7058篇
  国内免费   746篇
耳鼻咽喉   1217篇
儿科学   3940篇
妇产科学   2846篇
基础医学   18081篇
口腔科学   4651篇
临床医学   11394篇
内科学   28347篇
皮肤病学   3261篇
神经病学   12105篇
特种医学   2911篇
外国民族医学   1篇
外科学   11193篇
综合类   435篇
一般理论   56篇
预防医学   12337篇
眼科学   2110篇
药学   8725篇
中国医学   493篇
肿瘤学   9024篇
  2024年   147篇
  2023年   1222篇
  2022年   2664篇
  2021年   4427篇
  2020年   2746篇
  2019年   3714篇
  2018年   4224篇
  2017年   3156篇
  2016年   3690篇
  2015年   4061篇
  2014年   5346篇
  2013年   6939篇
  2012年   10604篇
  2011年   11006篇
  2010年   5944篇
  2009年   5014篇
  2008年   8620篇
  2007年   8576篇
  2006年   7879篇
  2005年   7329篇
  2004年   6565篇
  2003年   5813篇
  2002年   5213篇
  2001年   613篇
  2000年   422篇
  1999年   646篇
  1998年   878篇
  1997年   723篇
  1996年   604篇
  1995年   497篇
  1994年   459篇
  1993年   391篇
  1992年   312篇
  1991年   217篇
  1990年   211篇
  1989年   200篇
  1988年   188篇
  1987年   151篇
  1986年   167篇
  1985年   119篇
  1984年   154篇
  1983年   141篇
  1982年   164篇
  1981年   120篇
  1980年   126篇
  1979年   75篇
  1978年   81篇
  1977年   75篇
  1976年   60篇
  1974年   54篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
An unusual case of sundown syndrome is here reported, in which a bilingual patient would involuntarily change languages at sunset. Numerous theories have been advanced in attempting to account for sundowning. Cameron [1] has suggested that nocturnal delirium was based on an inability to maintain a spatial image without the assistance of repeated visualization. Krai [2] and Wolanin and Phillips [3] have argued for a more psychogenic account, by stating that psychosocial stressors may, in concert with impaired cognitive functioning, account for sundowning. The present case concerns a 42-year-old white male who in January 1989 suffered a closed head injury. A thorough personal history as well as a detailed examination of the patient's daily activities allowed us to account for the unusual manner in which the sundowning manifested itself. The uniqueness of this case allows us to underscore both the psychological as well as environmental and neurological factors involved in sundowning. Thus, we have as a consequence been able to synthesize the seemingly disparate accounts of both Cameron and more recent published literature [2, 3].  相似文献   
82.
Editors' note: As we approach the end of the 20th century, we will, in Nutrition Reviews, take an occasional look back at developments of the last half-century that have established the underpinnings of public health nutrition as we know it and practice it today. This is also a span of time over which this journal, having begun publication in 1942, has addressed important developments in nutrition and health. Our first retrospective is contributed by Dr. José Maria Bengoa, one of the fathers of international public health nutrition. Dr. Bengoa, whose career has spanned more than 50 years, witnessed the origins of the international nutrition agencies and served in leadership roles at the Pan American Health Organization and the World Health Organization (WHO) from 1955 to 1964, and as director of the WHO Office of Nutrition from 1964 to 1974.  相似文献   
83.
This study was designed to verify the safety and efficacy of botulinum toxin type A (BTX-A) used as a neuromuscular block on spastic masticatory musculature of children with cerebral palsy. Six patients who had spastic-tetraplegic cerebral-palsy, aged 5 to 20 years were selected. All patients had spasticity of the jaw muscles, bruxism, lower lip trauma, limited mouth opening, and difficulties in cleaning the oral cavity. The patients were sedated under general anesthesia, while the dentist injected the masseter and temporalis muscles bilaterally with 150 and 75 units of BTX-A each. Clinical examinations were conducted at 7, 14, 30, and 90 days after the initial appointment. We found statistically significant decreases in muscle spasticity and bruxism ( p = 0.002), improved inter-incisal opening ( p = 0.002), improved oral hygiene ( p = 0.031), and less lower lip trauma ( p = 0.060) after the neuromuscular blocking.  相似文献   
84.
Neurodevelopmental treatment (NDT) is the most used rehabilitation approach in the treatment of patients with stroke in the Western world today, despite the lack of evidence for its efficacy. The aim of this study was to conduct an intervention check and measure the nurses' competence, in positioning stroke patients according to the NDT approach. The sample consisted of 144 nurses in six neurological wards who were observed while positioning stroke patients according to the NDT approach. The nurses' combined mean competence scores within the wards was 195 (70%) of 280 (100%) possible, and for each ward the mean score varied between 181 (65%) and 206 (74%). This study indicates that nurses working in hospitals where the NDT approach has been implemented have the knowledge and skills to provide NDT nursing.  相似文献   
85.
S100A1 is a calcium-binding protein, which has been recently found in renal cell neoplasms. We evaluated the diagnostic utility of immunohistochemical detection of S100A1 in 164 renal cell neoplasms. Forty-one clear cell, 32 papillary, and 51 chromophobe renal cell carcinomas, and 40 oncocytomas, 164 samples of normal renal parenchyma adjacent to the tumors and 13 fetal kidneys were analyzed. The levels of S100A1 mRNA detected by quantitative RT-PCR analysis of frozen tissues from seven clear cell, five papillary, and six chromophobe renal cell carcinomas, four oncocytomas, and nine samples of normal renal tissues adjacent to neoplasms were compared with the immunohistochemical detection of protein expression. Clear cell and papillary renal cell carcinomas showed positive reactions for S100A1 in 30 out of 41 tumors (73%) and in 30 out of 32 (94%) tumors, respectively. Thirty-seven renal oncocytomas out of 40 (93%) were positive for S100A1, whereas 48 of 51 (94%) chromophobe renal cell carcinomas were negative. S100A1 protein was detected in all samples of unaffected and fetal kidneys. S100A1 mRNA was detected by RT-PCR in all normal kidneys and renal cell neoplasms, although at very different levels. Statistical analyses comparing the different expression of S100A1 in clear cell and chromophobe renal cell carcinomas observed by immunohistochemical and RT-PCR methods showed significant values (P<0.001), such as when comparing by both techniques the different levels of S100A1 expression in chromophobe renal cell carcinomas and oncocytomas (P<0.001). Our study shows that S100A1 protein is expressed in oncocytomas, clear cell and papillary renal cell carcinomas but not in chromophobe renal cell carcinomas. Its immunodetection is potentially useful for the differential diagnosis between chromophobe renal cell carcinoma and oncocytoma. Further, S100A1 protein expression is constantly detected in the normal parenchyma of the adult and fetal kidney.  相似文献   
86.
87.
BACKGROUND: Systemic sclerosis (SSc) is a connective tissue disorder of unknown etiology characterized by fibrosis of the skin and visceral organs, in which the heart is frequently (40-70% of patients) and severely involved. Pulmonary hypertension affects 10-15% of patients with SSc and is one of the most important complications adversely influencing their survival. CASE REPORT: The case report presents a 59-year-old male patient with advanced systemic sclerosis whose initial examination revealed pulmonary hypertension, rhythm and atrioventricular conduction disturbances, and elevated level of NT-proBNP. After six months the patient deteriorated; an increase in NT-proBNP level and progression of pulmonary hypertension were observed. CONCLUSIONS: The described case is followed by a discussion of cardiovascular involvement in systemic sclerosis and emphasizes that heart involvement in SSc may have very serious clinical implications.  相似文献   
88.
An in vitro assay, which evaluates drug effect on 3H-thymidine incorporation, was used to investigate the absolute and relative activities of cisplatin (DDP), carboplatin (CBDCA) and iproplatin (CHIP) on 317 specimens from untreated tumors, including breast and ovarian cancers and malignant melanomas. Similar activities were generally observed for DDP and CHIP, whereas CBDCA exhibited a lower, although not significantly different cytotoxicity on breast and ovarian cancers. The relative activities of Platinum analogues were analyzed on 239 two-way drug sensitivity comparisons. The overall agreement rates ranged from 80.2 to 83.9% for the different comparisons. High coresistance, from 61.1 to 93.8%, was observed for all the comparisons, regardless of the tumor type. Cosensitivity rates were poor for breast and ovarian cancers, from 0 to 37.5%, whereas for melanomas an association in sensitivity was observed in 80% of the cases.  相似文献   
89.
90.
Quisqualic acid NBM lesions had no effect on water maze performance, but slightly impaired passive avoidance acquisition. GammavinylGABA treatment alone had no effect on the passive avoidance and water maze performance, but aggravated acquisition deficit in rats subjected to NBM lesioning. However, gammavinylGABA-treated NBM-lesioned rats reached control level of performance.  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