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   26314篇
  免费   1725篇
  国内免费   82篇
耳鼻咽喉   222篇
儿科学   647篇
妇产科学   449篇
基础医学   3852篇
口腔科学   339篇
临床医学   2449篇
内科学   6348篇
皮肤病学   691篇
神经病学   2212篇
特种医学   811篇
外国民族医学   3篇
外科学   3795篇
综合类   270篇
一般理论   28篇
预防医学   1987篇
眼科学   495篇
药学   1613篇
  1篇
中国医学   56篇
肿瘤学   1853篇
  2022年   138篇
  2021年   339篇
  2020年   229篇
  2019年   363篇
  2018年   425篇
  2017年   291篇
  2016年   357篇
  2015年   413篇
  2014年   632篇
  2013年   951篇
  2012年   1409篇
  2011年   1569篇
  2010年   945篇
  2009年   960篇
  2008年   1493篇
  2007年   1662篇
  2006年   1659篇
  2005年   1751篇
  2004年   1604篇
  2003年   1528篇
  2002年   1517篇
  2001年   403篇
  2000年   335篇
  1999年   396篇
  1998年   376篇
  1997年   335篇
  1996年   291篇
  1995年   276篇
  1994年   254篇
  1993年   230篇
  1992年   313篇
  1991年   295篇
  1990年   267篇
  1989年   250篇
  1988年   216篇
  1987年   211篇
  1986年   228篇
  1985年   218篇
  1984年   207篇
  1983年   199篇
  1982年   222篇
  1981年   230篇
  1980年   183篇
  1979年   139篇
  1978年   133篇
  1977年   140篇
  1976年   114篇
  1975年   111篇
  1974年   103篇
  1973年   94篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
(1) The estrous cycle in the rat may be used to study recurrent changes in motor behaviors and motivation which are strongly related to cyclic hormonal and CNS changes. (2) The peak in motivated behaviors occurs during a sharply defined period on the night between proestrus and estrus and is evident in facilitated wheel-running, lordosis, and intracranial self-stimulation. (3) Behaviors without a clearly motivated character do not show an estrous cyclicity. (4) The estrous cyclic variation in intracranial self-stimulation was observed at a specific locus — the pars campacta of the substantia nigra. (5) A neurochemical link between sexually motivated behavior, wheel running and intracranial self-stimulation is suggested. This link is in part dopaminergic but is probably also activated by many other systems.  相似文献   
2.
3.
4.
ImmunoCyt/uCyt is a fluorescent test combining three monoclonal antibodies. In this study, it has been tested as a complement to cytology in the detection of urothelial carcinoma in urine. It has been performed simultaneously with standard cytology and cystoscopy on 870 urine analyses from one hospital. In 136 cases, one or more bladder tumors were found. Overall sensitivity of cytology, ImmunoCyt/uCyt and combined analyses reached 29, 74 and 84%, respectively, and overall specificity was 98, 62 and 61%. The negative predictive value of cytology, ImmunoCyt/uCyt and both analyses was 88, 93 and 95%, respectively, and the positive predictive value was 70, 26 and 29%. The sensitivity of cytology for low malignant potential neoplasms, low- and high-grade papillary carcinomas was 6, 18 and 53%, while it reached 71, 79 and 93% when combined with ImmunoCyt/uCyt. The sensitivity of cytology for stages Ta, T1, T2 and over and Tis tumors was 12, 67, 47 and 50%, while it reached 78, 83, 79 and 100% when combined with ImmunoCyt/uCyt. In the absence of tumor on cystoscopy but with positive ImmunoCyt/uCyt, 18% of patients developed a tumor, 2-6 months later. Of the 109 cases diagnosed as suspicious for malignancy by cytology, a tumor was present in 30 cases and ImmunoCyt/uCyt was positive in 22 (73%) of them. In conclusion, ImmunoCyt/uCyt may be used to postpone cystoscopies in patients followed for bladder cancer and may help to save cytologist and pathologist screening time.  相似文献   
5.
6.
This cross-sectional analysis evaluated the effect of age and body mass index (BMI) on Three-Factor Eating Questionnaire scores in males. Subjects (n = 60) were recruited according to BMI status. Each completed the 51-item Three-Factor Eating Questionnaire. The group was split at the median age to produce a “younger” and “older” group for statistical analysis. A 2-way between-groups analysis of variance revealed a significant main effect of BMI on disinhibition (P = .003) and hunger (P = .041) with higher levels found in overweight males compared to healthy-weight counterparts. A significant main effect of age on hunger (P = .046) demonstrated older males were less susceptible to hunger than younger males. These insights provide a better understanding of eating behavior across the male life cycle and may assist health professionals to better guide men in weight management in the light of rising overweight/obesity.  相似文献   
7.
8.
Bernard Gitler 《Journal of nuclear cardiology》2007,14(6):904; author reply 904-904; author reply 905
  相似文献   
9.
10.
A computer-assisted method for the registration of food intakes in real time according to a concise and simple procedure was subjected to a series of controls in order to assess precision. The method employs the 'portion' of a composite dish as unit of measure. The constancy of the portion was tested. The results show that the recipes of the diet of a subject may be stored and utilized in deferred time without loss of precision: data to be recorded in real time are then very limited. The length of period of analysis was also studied. The time of investigation should not be shorter than two weeks to obtain precise information on the feeding habits of an individual subject, whereas for a group of subjects the diary of a single day provides information of sufficient precision.  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