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   3805篇
  免费   206篇
  国内免费   14篇
耳鼻咽喉   49篇
儿科学   162篇
妇产科学   284篇
基础医学   478篇
口腔科学   49篇
临床医学   286篇
内科学   731篇
皮肤病学   46篇
神经病学   320篇
特种医学   89篇
外科学   557篇
综合类   13篇
一般理论   1篇
预防医学   151篇
眼科学   132篇
药学   207篇
中国医学   1篇
肿瘤学   469篇
  2022年   20篇
  2021年   69篇
  2020年   35篇
  2019年   56篇
  2018年   84篇
  2017年   55篇
  2016年   62篇
  2015年   84篇
  2014年   105篇
  2013年   151篇
  2012年   187篇
  2011年   228篇
  2010年   126篇
  2009年   103篇
  2008年   208篇
  2007年   268篇
  2006年   276篇
  2005年   279篇
  2004年   259篇
  2003年   260篇
  2002年   204篇
  2001年   43篇
  2000年   48篇
  1999年   46篇
  1998年   46篇
  1997年   30篇
  1996年   36篇
  1995年   46篇
  1994年   34篇
  1993年   40篇
  1992年   43篇
  1991年   37篇
  1990年   37篇
  1989年   27篇
  1988年   24篇
  1987年   31篇
  1986年   30篇
  1985年   17篇
  1984年   27篇
  1983年   31篇
  1982年   17篇
  1981年   24篇
  1980年   18篇
  1979年   14篇
  1978年   19篇
  1977年   23篇
  1976年   15篇
  1974年   11篇
  1972年   11篇
  1971年   10篇
排序方式: 共有4025条查询结果,搜索用时 15 毫秒
1.
2.
3.
OBJECTIVE: Little is known about the interactions of sports-related demands and human body, in particular on musculoskeletal features, during growth. Focusing on the relationship between soccer and lower limb alignment, we examined the hypothesis that varus knee deviation is more prevalent among high-performance pediatric and adolescent soccer players. DESIGN: Cross-sectional study with focused sampling. SETTING: First league sports clubs. PARTICIPANTS: 106 male child/adolescent soccer players aged 10 to 21 years and 68 age-matched tennis players. INTERVENTIONS: All athletes completed a demographic questionnaire and underwent physical examinations, which included height, weight, generalized laxity, knee, ankle, foot and spine axis, hip range of motion, tibial torsion, Q angle, foot navicular height, and progression angle. MAIN OUTCOME MEASUREMENT: Varus/valgus axis was determined by the intercondylar intermalleolar distance while standing. Soccer and tennis players were compared on knee axis and other outcome variables by analysis of covariance, adjusting for age and by t-tests within age groups. RESULTS: A significantly higher prevalence of knee varus was found among the soccer players compared to that among the tennis players. The difference in intracondylar distance was statistically significant after the age of 13 years (P < 0.001). In addition, compared to tennis players, soccer players had higher foot arches, decreased hip external rotation and increased external tibial torsion. CONCLUSIONS: Varus knee axis deviation was more common among children and adolescent soccer players than among tennis players. The prevalence was more pronounced among players aged 13 years or older. Further research is needed to explore the rationale of this phenomenon.  相似文献   
4.
The aim of this study is to assess accuracy of transvaginal ultrasound (TVUS) and diagnostic hysteroscopy in diagnosing endometrial polyps and to determine premalignancy and malignancy rates in asymptomatic women. The study was designed to retrospectively analyze 438 women who underwent operative hysteroscopy in a day-care unit when endometrial polyp was suspected after TVUS and diagnostic hysteroscopy. Multivariate logistic regression modeling showed effects of age, previous breast cancer with tamoxifen treatment, and menopause with or without bleeding on pathologic results. The results indicate that positive predictive value of TVUS with diagnostic hysteroscopy was 79.9%. Premalignancy or malignancy occurred in 3.2% and was significantly related to menopause with abnormal bleeding (P < 0.001), which carried a 20-fold higher risk of pathology than any other group. Age was also a risk factor. It was concluded that TVUS with diagnostic hysteroscopy reliably evaluates endometrial polyps. The low incidence of endometrial tumors in asymptomatic (especially premenopausal) women suggests that their operative evaluation may not be cost effective. Larger studies are needed to support this tentative conclusion.  相似文献   
5.
Familial Sneddon's syndrome   总被引:4,自引:0,他引:4  
We report the familial occurrence and apparent autosomal dominant inheritance of Sneddon's syndrome with variable clinical expression. The proband, a 40-year-old woman, presented with livedo reticularis and progressive neurological deterioration following a stroke. The diagnosis was confirmed by cerebral angiogram and skin biopsy, both showing the characteristic findings. Two of the patient's sisters were reported to have been similarly affected in the past. Her mother, two additional siblings and five of her seven children exhibited various vasospastic skin phenomena. Familial aggregation of this disorder may be common and a genetic basis may be involved in its pathogenesis.  相似文献   
6.
7.
Neurofibromatosis type 1 (NF 1) is a syndrome with a predisposition for benign and malignant tumor development. Of the malignant neoplasms, osteogenic sarcomas are rare but have been described. There are some reports of patients with neurofibromatosis type 1 with a parathyroid adenoma and hyperparathyroidism. Also, there are studies that imply that the parathyroid hormone plays a role in the regulation and modulation of oseogenic sarcomas in vitro. We report about a 50-year-old female suffering from neurofibromatosis type 1, with a 3-year documented history of untreated hyperparathyroidism and a parathyroid adenoma. The patient developed a mandibular osteogenic sarcoma. To our knowledge, this is the first reported case occurring in the mandible. The unusual tumor site for a patient with neurofibromatosis type 1, the conjugation with hyperparathyroidism and the rapid growth of an osteogenic sarcoma are intriguing.  相似文献   
8.
Thirty-three patients with primary gastrointestinal lymphoma (GIL) followed at Ankara University Medical School have been evaluated. The most frequent locations of the disease are the small intestine (48.4%) and the stomach (39.3%). The intermediate and high grade lymphomas constitute 84.8% of the cases. The mean age of the patients with small intestinal lymphoma is 28.7 years and 47.1 years for those with gastric lymphoma. The patients treated with surgery and chemotherapy (S+CT) have a longer survival than those treated with chemotherapy (CT) alone. In conclusion: 1) Small intestinal lymphoma occurs more frequently than gastric lymphoma in our study. 2) The median age of the Turkish patients with primary GIL is approximately 10 years less than those in the Western countries. 3) The therapeutic results of S+CT are superior to those of CT in the early stages of the disease.  相似文献   
9.
10.
Gene amplification occurs frequently in tumour tissues yet is,in general, non-inheritable. To study the molecular mechanismsconferring this restraint, we created transgenic mice carryinga human butyrylcholinesterase (BCHE) coding sequence, previouslyfound to be amplified in a father and son. Blot hybridizationof tail DNA samples revealed somatic transgene amplificationswith variable restriction patterns and intensities, suggestingthe occurrence of independent amplification events, in 31% (11/35)of mice from the FII generation but in only 3.5% (2/58) of theFII and FIV generations. In contrast, >10-fold amplificationsof the BCHE transgene and the endogenous acetylcholinesteraseand c-raf genes appeared in both testis and epididymis DNA from>80% of FIII mice. Drastic, selective reductions in testisBCHEmRNA but not in actin mRNA were detected by the PCR amplificationof testis cDNA from the transgenic mice, and apparently resultedin the limited transmission of amplified genes. The testicularamplification of the BCHE transgene may potentially representa general phenomenon with clinical implications in human infertility.  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