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   1402359篇
  免费   104045篇
  国内免费   2102篇
耳鼻咽喉   20533篇
儿科学   48790篇
妇产科学   37979篇
基础医学   200747篇
口腔科学   37831篇
临床医学   121733篇
内科学   280232篇
皮肤病学   31673篇
神经病学   113216篇
特种医学   56350篇
外国民族医学   660篇
外科学   214641篇
综合类   27615篇
现状与发展   1篇
一般理论   413篇
预防医学   102749篇
眼科学   30672篇
药学   103287篇
  2篇
中国医学   2605篇
肿瘤学   76777篇
  2019年   10421篇
  2018年   15811篇
  2017年   12261篇
  2016年   13855篇
  2015年   14926篇
  2014年   19973篇
  2013年   31255篇
  2012年   42451篇
  2011年   45373篇
  2010年   26921篇
  2009年   24617篇
  2008年   44032篇
  2007年   46990篇
  2006年   46981篇
  2005年   45794篇
  2004年   44550篇
  2003年   43395篇
  2002年   42626篇
  2001年   67995篇
  2000年   71585篇
  1999年   59371篇
  1998年   16412篇
  1997年   14787篇
  1996年   15035篇
  1995年   14150篇
  1994年   13462篇
  1993年   12437篇
  1992年   45242篇
  1991年   44048篇
  1990年   42756篇
  1989年   40669篇
  1988年   37370篇
  1987年   36784篇
  1986年   34065篇
  1985年   32906篇
  1984年   24771篇
  1983年   20798篇
  1982年   12274篇
  1981年   11188篇
  1979年   21767篇
  1978年   15259篇
  1977年   12976篇
  1976年   12051篇
  1975年   12992篇
  1974年   15011篇
  1973年   14418篇
  1972年   13180篇
  1971年   11981篇
  1970年   11280篇
  1969年   10216篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Background  Coccygodynia can cause severe pain and disability in patients. There are contradictions in the literature regarding the final results of coccygectomy for coccygodynia. We evaluated the long-term effects of coccygectomy on the intensity, characteristics, and manifestation of pain caused by coccygodynia to determine the adequacy of operation among treatment modalities. Materials and methods  Thirty-four patients with coccygodynia were treated by coccygectomy. In 22 cases, trauma, and in one case childbirth was the cause. 11 cases were regarded as idiopathic. The intensity, characteristics of pain, and the most painful activities were evaluated at an average of 7.6 (3–18) years of follow-up time. Results  Before the operation, all 34 patients had pain while sitting, moreover, 26 of them had pain during standing, walking, at night or a combination of these. 21 patients had intolerable or very intensive, mainly acute, sharp or burning pain. 11 patients had dyschesia, 2 had dysuria and 6 had dyspareunia. At follow-up, 7 patients were completely free of pain, 15 others had moderate, 11 medium, and only one patient had severe, but none had intolerable pain. Only seven patients had acute, sharp or burning pain postoperatively. The decrease of average pain score from 8.0 to 3.2 was significant (P < 10−12). The number of the patients with dyschesia and dyspareunia decreased from 11 to 7 and from 6 to 3, respectively. Two patients had dysuria, but their complaints did not change after the operation. One of the two patients who needed reoperation had an excellent final result, while the other remained unchanged. 12 and 16 patients (together 82%) regarded the final result of the operation excellent and good, respectively. The condition of five others did not change, while one became worse. The patients with younger age, smaller body mass index, and less co-morbidities had better final result. There were no serious complications. Conclusion  Coccygectomy for coccygodynia is a safe method to decrease the intensity of pain and other complaints of the patients. The operation can be the choice of treatment if conservative measures fail.  相似文献   
994.
995.
Introduction and objectiveWhen sleep apnea-hypopnea syndrome (SAHS) and cardiovascular disease occur concurrently, prognosis is affected. Echocardiography can detect structural cardiac abnormalities but using this technique in all patients would place a heavy burden on resources. The objective of this study was to investigate whether the N-terminal fraction of brain natriuretic peptide (NT-proBNP) can be used as a marker for silent heart disease.Patients and methodsNT-proBNP concentration was measured in the 114 consecutive patients with SAHS who underwent echocardiography before starting treatment. Left and right ventricular systolic and diastolic function, as well as structural abnormalities, were studied. Correlations between NT-proBNP concentration and the abnormalities detected were investigated. A receiver operating characteristics (ROC) curve was plotted for NT-proBNP concentration and cardiac abnormalities.ResultsData for 98 patients were finally analyzed. NT-proBNP concentration was significantly correlated with ventricular septal thickness (r=0.63), posterior wall thickness (r=0.45), and left ventricular enddiastolic diameter (r=0.51) (P<.0001 for all correlations). The area under the ROC curve was significant (0.870; 95% confidence interval, 0.801-0.939; P<.0001). Assuming that specificity would be more useful for clinical practice, we calculated that NT-proBNP concentrations below 100 and 200 pg/mL could rule out structural abnormalities with a reliability of 90% and 100%, respectively.ConclusionsNT-proBNP concentration was strongly correlated with echocardiographic abnormalities and so could be a useful tool for identifying patients who should be referred to the cardiologist.  相似文献   
996.
997.
Damage to the genetic component of spermatozoa seems to play the main role in a majority of cases where current approaches fail to reveal the specific cause of male infertility. In this study, we compared semen quality in men assigned to two defined groups: men from couples with unexplained infertility – idiopathic infertility (A) and young men with no experiences of infertility (B). All samples were examined by standard ejaculate analysis and sperm chromatin structure assay (SCSA). Sperm chromatin damage was significantly higher in men from group A than in those from group B. Similar results were obtained by comparison of men from group A (all men were normozoospermic) with normozoospermic men from group B. According to these results, we can suppose that chromatin disorders may be the causal factor of subfertility or infertility in some of these men. No evidence for a strong association between chromatin disorders and standard parameters of ejaculates was found. We failed to confirm a relationship between smoking and sperm quality in men from any of the investigated groups. SCSA is a method that facilitates the identification of infertile men who otherwise show normal semen variables.  相似文献   
998.
999.
1000.
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