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   186371篇
  免费   11786篇
  国内免费   902篇
耳鼻咽喉   1772篇
儿科学   4683篇
妇产科学   3341篇
基础医学   26981篇
口腔科学   4129篇
临床医学   17447篇
内科学   38917篇
皮肤病学   3633篇
神经病学   18296篇
特种医学   7584篇
外国民族医学   6篇
外科学   27680篇
综合类   2071篇
现状与发展   2篇
一般理论   154篇
预防医学   12841篇
眼科学   3905篇
药学   12940篇
  2篇
中国医学   265篇
肿瘤学   12410篇
  2023年   932篇
  2022年   1404篇
  2021年   3177篇
  2020年   2243篇
  2019年   3281篇
  2018年   3970篇
  2017年   3077篇
  2016年   3598篇
  2015年   4126篇
  2014年   5788篇
  2013年   7942篇
  2012年   12092篇
  2011年   12850篇
  2010年   7479篇
  2009年   7135篇
  2008年   11953篇
  2007年   12710篇
  2006年   12043篇
  2005年   12386篇
  2004年   11677篇
  2003年   11152篇
  2002年   10634篇
  2001年   1896篇
  2000年   1481篇
  1999年   2044篇
  1998年   2597篇
  1997年   2055篇
  1996年   1785篇
  1995年   1624篇
  1994年   1426篇
  1993年   1362篇
  1992年   1038篇
  1991年   1034篇
  1990年   822篇
  1989年   790篇
  1988年   769篇
  1987年   758篇
  1986年   683篇
  1985年   747篇
  1984年   843篇
  1983年   753篇
  1982年   974篇
  1981年   882篇
  1980年   744篇
  1979年   495篇
  1978年   527篇
  1977年   547篇
  1976年   483篇
  1975年   394篇
  1974年   365篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
The functional significance of the pars tuberalis (PT) of the mammalian adenohypophysis has remained an enigma (1, 2). One view of its function is that it acts as an auxiliary gland to support the endocrine role of the pars distalis (PD) (2), as it has been shown to contain immunocytochemically identifiable thyrotrophs and gonadotrophs (1). Many of the cells of the PT are, however, ultrastructurally unique suggesting an independent function for this tissue. Our recent demonstration that the PT of the rat is a major binding site for the ligand iodomelatonin lends further support to this idea (3). We have utilized the highly specific ligand [125l]melatonin, and have demonstrated that it binds exclusively, with very high affinity, to the PT but not the PD of the adult sheep adenohypophysis. These findings support the conclusion that the PT has a distinct role in relation to melatonin action and seasonal reproduction.  相似文献   
43.
44.
45.
46.
The reconstruction of a part of the body that has lost or inhibited function has been the most important aspect of reconstructive surgery in the past. Because of the existence of better techniques and the patient's wish for social reintegration, the plastic surgeon today is forced to consider the aesthetic results of his work more than in the past. Sometimes microsurgical procedures in reconstructive surgery are the only chance for the patient to be healed or palliated. Experience with more than 350 free tissue transfers gave us the opportunity to estimate the value of a donor flap with respect to the requirements of the receiving site. To satisfy the high aesthetic demands in these cases, it was necessary for the right place and shape the flap to fit as closely as possible, even if further corrections were necessary to achieve a satisfactory result. The transfer of latissimus dorsi and radial forearm flaps to the face and lower leg is discussed in cases of tumorus diseases and severe injuries of young and old patients.Presented to the IXth Congress of the International Society of Aesthetic Plastic Surgery, New York, October 13, 1987  相似文献   
47.
48.
PURPOSE: Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors. PATIENTS AND METHODS: Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28). RESULTS: Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults. CONCLUSION: Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued.  相似文献   
49.
BACKGROUND: The dopamine transporter (DAT) is known to be a key regulator of dopamine, and recent studies of genetics, treatment, and imaging have highlighted the role of DAT in attention-deficit/hyperactivity disorder (ADHD). The findings of in vivo neuroimaging of DAT in ADHD have been somewhat discrepant, however. METHOD: Dopamine transporter binding was measured using a highly selective ligand (C-11 altropane) and positron emission tomography (PET). The sample consisted of 47 well-characterized, treatment-na?ve, nonsmoking, non-comorbid adults with and without ADHD. Additionally, control subjects had few symptoms of ADHD. RESULTS: Results showed significantly increased DAT binding in the right caudate in adults with ADHD compared with matched control subjects without this disorder. CONCLUSIONS: These results confirm abnormal DAT binding in the striatum of adults with ADHD and provide further support that dysregulation of DAT may be an important component of the pathophysiology of ADHD.  相似文献   
50.
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   
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