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   7327篇
  免费   507篇
  国内免费   28篇
耳鼻咽喉   120篇
儿科学   419篇
妇产科学   175篇
基础医学   1057篇
口腔科学   58篇
临床医学   525篇
内科学   1522篇
皮肤病学   220篇
神经病学   282篇
特种医学   183篇
外科学   738篇
综合类   559篇
一般理论   1篇
预防医学   487篇
眼科学   176篇
药学   635篇
中国医学   36篇
肿瘤学   669篇
  2023年   41篇
  2022年   66篇
  2021年   182篇
  2020年   105篇
  2019年   121篇
  2018年   145篇
  2017年   122篇
  2016年   160篇
  2015年   210篇
  2014年   244篇
  2013年   301篇
  2012年   441篇
  2011年   428篇
  2010年   299篇
  2009年   272篇
  2008年   377篇
  2007年   349篇
  2006年   326篇
  2005年   298篇
  2004年   286篇
  2003年   243篇
  2002年   220篇
  2001年   205篇
  2000年   193篇
  1999年   155篇
  1998年   97篇
  1997年   97篇
  1996年   99篇
  1995年   79篇
  1994年   76篇
  1993年   56篇
  1992年   111篇
  1991年   98篇
  1990年   98篇
  1989年   77篇
  1988年   93篇
  1987年   84篇
  1986年   75篇
  1985年   75篇
  1984年   51篇
  1983年   47篇
  1979年   54篇
  1978年   44篇
  1976年   42篇
  1975年   40篇
  1974年   45篇
  1973年   37篇
  1972年   52篇
  1971年   37篇
  1970年   37篇
排序方式: 共有7862条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
OBJECTIVE: To evaluate the procedure in terms of technical difficulties, patient satisfaction, symptom relief, recurrence, and further management. STUDY DESIGN: Retrospective study including 41 patients who underwent endoscopic stapling diverticulotomy. Clinical notes were reviewed, and patients were sent a patient satisfaction questionnaire. Statistical analysis was done using the chi(2) square test. SETTING: Teaching hospital. RESULTS: Larger pouches had the best results; 81.578% were satisfied with the surgery, and 86.84% had improved swallowing. Complications presented in 6 patients (15%), including a perforated pouch and an esophageal perforation. Complications were more frequent in small pouches. CONCLUSIONS AND SIGNIFICANCE: Endoscopic stapling diverticulotomy offers rapid recovery in most patients, with early oral intake and short hospital stay. There is a high degree of symptoms relief, and the patient's satisfaction rate is high. The assessment of the pharyngeal pouch size is an important factor when deciding the best management for a patient with a pharyngeal pouch.  相似文献   
25.
38 cases of sarcoma of head and neck region were analysed in a retrospective way in relation to age, anatomic location, histological, clinical profile, and surgical approaches. Compared to other types of head and neck neoplasms, such as squamous cell carcinoma, soft tissue sarcomas have low rates of regional metastases. However the biological behaviour of soft tissue sarcoma is more aggressive specially in paediatric age group. In the present series, CT scan was considered as the primary modality of investigation. Surgery generally has been recommended as the primary method of treatment for achieving local control, except in those high-grade tumours arising in sites not amenable to resection. 3-year and 5-year survival rates in this present series 50% and 31.6% respectively.  相似文献   
26.
27.
28.
M R Ray  A Ghosh  S K Nandi 《Neoplasma》1991,38(1):69-76
Significant increase (p less than 0.05) in circulating platelet counts was observed in a wide spectrum of experimental tumors in mice. The mechanism of this abnormality was investigated in strain A mice bearing a transplantable ascites tumor, Sarcoma 180 (S 180). Thrombocytosis observed in the tumor hosts was not due to prolonged platelet surviva], as 51Cr platelet half-life was normal. On the other hand, stimulation of thrombopoiesis, expressed in terms of platelet 75Selenomethionine (75SeM) incorporation, appeared to be the primary reason for elevated platelet counts in the tumor-bearers. Evaluation of thrombopoietic activity in the femoral marrow and spleen by measuring organ uptake of 75SeM and megakaryocyte counts indicated that tumor-induced stimulation in thrombopoiesis may be attributed to enhancement in splenic activity. Pretreatment of normal mice with tumor ascites or tumor cell-conditioned medium resulted in enhancement in thrombopoiesis. The findings suggest the production of some factor(s) by the tumor cells which probably mediate the stimulation of platelet production in tumor hosts.  相似文献   
29.
The first example of mechanism-based inactivation of angiotensin-converting enzyme (ACE) is described for N-[N-(cyanoacetyl)-L-phenylalanyl]-L-phenylalanine (compound 1). It is proposed that an ACE-mediated deprotonation of 1 unmasks a ketenimine intermediate, which traps an active-site nucleophile, and hence irreversibly modifies the enzyme. In competition with the inactivation reaction, ACE also hydrolyzes 1 with a partition ratio of 8300 (i.e., kcat/kinact). Since the corresponding keto analogue, N-[(R)-2-benzyl-5-cyano-4-oxopentanyl]-L-phenylalanine (compound 4), does not inactivate the enzyme, it is suggested that the NH in compound 1 is critical for the proper active-site anchoring of the inhibitor for the inactivation process to take place.  相似文献   
30.
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