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   1034686篇
  免费   67317篇
  国内免费   1365篇
耳鼻咽喉   13738篇
儿科学   28018篇
妇产科学   24800篇
基础医学   145221篇
口腔科学   29023篇
临床医学   87047篇
内科学   204691篇
皮肤病学   19938篇
神经病学   82253篇
特种医学   41214篇
外国民族医学   80篇
外科学   169598篇
综合类   18871篇
现状与发展   1篇
一般理论   248篇
预防医学   71071篇
眼科学   22404篇
药学   77977篇
  3篇
中国医学   2197篇
肿瘤学   64975篇
  2018年   20231篇
  2017年   16136篇
  2016年   18600篇
  2015年   9441篇
  2014年   12557篇
  2013年   18103篇
  2012年   27575篇
  2011年   35331篇
  2010年   22881篇
  2009年   20341篇
  2008年   35148篇
  2007年   38667篇
  2006年   27091篇
  2005年   27835篇
  2004年   27365篇
  2003年   27644篇
  2002年   25947篇
  2001年   55282篇
  2000年   57332篇
  1999年   47341篇
  1998年   10993篇
  1997年   9780篇
  1996年   9803篇
  1995年   9134篇
  1994年   8484篇
  1993年   7754篇
  1992年   35741篇
  1991年   34152篇
  1990年   32946篇
  1989年   32068篇
  1988年   29166篇
  1987年   28434篇
  1986年   26455篇
  1985年   25304篇
  1984年   17935篇
  1983年   15235篇
  1982年   7892篇
  1981年   6798篇
  1979年   15901篇
  1978年   10677篇
  1977年   9086篇
  1976年   7954篇
  1975年   8641篇
  1974年   10505篇
  1973年   9885篇
  1972年   9369篇
  1971年   8867篇
  1970年   8458篇
  1969年   7968篇
  1968年   7230篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
最近提出的关于额叶功能的理论认为前额叶皮质,尤其是其背外侧面在确定适合一项特殊任务的一系列反应中起重要作用,并在选择中使上述反应发生偏差。这些活动事实上是为任何类型的非常规任务而执行,而不考虑内容的差别。本研究旨在通过一项解决“洞察力”问题的测试任务(即火柴杆算术作业),来验证Frith“塑造反应空间”假说的预测效力。从Knoblich等人对健康人不能解决火柴杆问题的解释和Frith关于额叶背外侧皮质作用的理论,作者推导出与直觉相左的预测,即对这些相对复杂的任务,外侧额叶皮质局部损伤的患者可能比1组健康受试者完成得更好。要求35例经CT或MRI扫描证实为单个局部脑损伤的患者(年龄为26—65岁)和23例健康受试者(年龄为34—62岁)完成火柴杆作业。研究结果似乎与理论上的预测相一致,虽然仅有43%的健康受试者能解决最困难的火柴杆问题(“C类”),但是却有82%的额叶外侧损伤患者完成了类似问题(Fisher精确概率检验,P〈0.05)。总之,对Frith和Knoblich等人理论的结合进行了确证。  相似文献   
53.
We report a case of cervical necrotizing fasciitis (CNF) in a female having uncontrolled type II diabetes mellitus. The patient was presented to us after 20 days of preliminary symptoms. The aetiology of microbial inoculation in subdermal tissue was not known. The isolate was Staphylococcus aureus. In spite of the delay in presentation, the patient was successfully treated with combined antimicrobial and surgical intervention.  相似文献   
54.
Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 ± 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin‐embedded tissues revealed the presence of the virus‐like particles with an average diameter between 70 and 90 nm.  相似文献   
55.
BACKGROUND: Impaired neuropsychological test performance, especially on tests of executive function and attention, is often seen in children diagnosed with autism spectrum disorders (ASD). Structures involved in fronto-striatal circuitry, such as the caudate nucleus, may support these cognitive abilities. However, few studies have examined caudate volumes specifically in children with ASD, or correlated caudate volumes to cognitive ability. METHODS: Neuropsychological test scores and caudate volumes of children with ASD were compared to those of children with bipolar disorder (BD) and of typically developing (TD) children. The relationship between test performance and caudate volumes was analyzed. RESULTS: The ASD group displayed larger right and left caudate volumes, and modest executive deficits, compared to TD controls. While caudate volume inversely predicted performance on the Wisconsin Card Sorting Test in all participants, it differentially predicted performance on measures of attention across the ASD, BD and TD groups. CONCLUSIONS: Larger caudate volumes were related to impaired problem solving. On a test of attention, larger left caudate volumes predicted increased impulsivity and more omission errors in the ASD group as compared to the TD group, however smaller volume predicted poorer discriminant responding as compared to the BD group.  相似文献   
56.
57.
58.
59.
60.
BACKGROUND: Obsessive-compulsive disorder (OCD) is a chronic, impairing and often comorbid disorder. METHODS: 1000 subjects who called the Anxiety Disorders Association of America (ADAA) were surveyed and divided in three groups: (a) callers with OCD (OCD) and two overlapping control groups: (b) callers with no axis I disorder (NAC) and (c) with no-OCD (NOC) using a 97-item questionnaire. RESULTS: The rate of OCD was 14.5% (N = 145). Relative to the NOC group, OCD subjects were more likely to be female, White, younger and not married. Relative to the NAC group, subjects with OCD were more likely to be White, not married and younger. OCD was accompanied by significant comorbidity and was associated with an increased number of visits to health professionals than NAC subjects. There was no significant difference regarding unemployment rates among the three groups. However, OCD callers were more likely than both control groups to have missed work or have decreased productivity due to their mental condition. OCD subjects took an average of 1 psychotropic medication in the past year and were statistically more likely than the control groups to experience sleepiness and nervousness as side effects. CONCLUSIONS: OCD was fairly prevalent among ADAA callers and presented high levels of comorbidity, impairment, health care utilization and sensitivity to psychotropic side effects.  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