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   20555篇
  免费   1320篇
  国内免费   259篇
耳鼻咽喉   481篇
儿科学   197篇
妇产科学   278篇
基础医学   3275篇
口腔科学   343篇
临床医学   1477篇
内科学   4315篇
皮肤病学   672篇
神经病学   1498篇
特种医学   1362篇
外科学   3018篇
综合类   68篇
一般理论   3篇
预防医学   648篇
眼科学   424篇
药学   1730篇
中国医学   268篇
肿瘤学   2077篇
  2024年   18篇
  2023年   167篇
  2022年   507篇
  2021年   840篇
  2020年   334篇
  2019年   584篇
  2018年   689篇
  2017年   513篇
  2016年   840篇
  2015年   1108篇
  2014年   1303篇
  2013年   1363篇
  2012年   2019篇
  2011年   1839篇
  2010年   1169篇
  2009年   974篇
  2008年   1310篇
  2007年   1213篇
  2006年   951篇
  2005年   899篇
  2004年   715篇
  2003年   611篇
  2002年   534篇
  2001年   301篇
  2000年   253篇
  1999年   185篇
  1998年   103篇
  1997年   86篇
  1996年   66篇
  1995年   66篇
  1994年   48篇
  1993年   45篇
  1992年   79篇
  1991年   66篇
  1990年   46篇
  1989年   39篇
  1988年   42篇
  1987年   42篇
  1986年   29篇
  1985年   25篇
  1984年   15篇
  1983年   10篇
  1981年   9篇
  1980年   10篇
  1979年   10篇
  1978年   6篇
  1976年   7篇
  1973年   7篇
  1971年   6篇
  1968年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The effect of postoperative epidural bupivacaine on intestinal motility was studied by measuring the transit time of barium contrast through the intestines in 16 patients after resection of the left colon and/or rectum. Fourteen patients served as controls and received postoperative injections of pentazocine. Mean transit time through the intestinal tract was 35 h in the epidural group and 150 h in the control group, a difference that is significant at the 0.1 per cent level. The average time before passage of flatus and faeces was different between the two groups at the 0.1 per cent level. We conclude that postoperative epidural bupivacaine constitutes an effective means of analgesia after colorectal surgery and is associated with a short duration of intestinal paralysis.  相似文献   
42.
We considered performing living donor liver transplantation (LDLT) in a larger-size recipient. When the recipient was large-sized, or when the donor liver was severely steatotic or had a right-to-left volume discrepancy. We devised dual living donor liver transplantation (DLDLT) to make up for graft size insufficiency and to secure the donor's safety. However, portal vein thrombosis (PVT) presented a challenge for DLDLT because of the need for intact right and left portal veins for the implantation of both liver grafts. Our 52-year-old male patient with hepatitis B cirrhosis had suffered from repeated esophageal and gastric variceal bleeding and underwent 2 trials of a transjugular intrahepatic portosystemic shunt (TIPS). He developed TIPS occlusion and PVT involving the area just above the spleno-mesenteric confluence to the right and left PV. Also, the right PV orifice was destructed and difficult to isolate because of severe periportal inflammation and neointima growth in the TIPS mesh. The patient's two sons were inadequate for donation because of right-to-left volume discrepancy. Therefore, DLDLT using 2 left lobes was necessary to compensate for graft-size insufficiency and to secure donor safety, and we substituted an intact umbilical portion of recipient's left PV for the destroyed right PV. The patient recovered well, and liver function has been normal for more than a year. In conclusion, the umbilical portion of recipient's left PV can be a useful vascular substitute for the reconstruction of a thrombosed main portal branch in DLDLT.  相似文献   
43.
BACKGROUND/AIMS: Carcinogenesis is characterized by the abnormal regulation of cell cycle. The abnormal expression of the regulators of cell cycle may be related to the prognosis. Since the clinical significance of the expression of the three proteins in colorectal carcinomas is still controversial, we evaluated the prognostic value of the expression of cyclin E, p27 and mutant p53 in stage II colorectal cancer. METHODS: The expression levels of cyclin E, p27 and mutant p53 proteins in 41 patients with stage II colorectal carcinomas were analyzed by immunohistochemistry. RESULTS: In the univariate analysis, the level of CEA at diagnosis was associated with disease relapse. In the multivariate analysis, the clinicopathological variables such as age, gender, site of primary tumor, tumor size, state of tumor differentiation and preoperative plasma CEA level were not associated with disease relapse. When Kaplan-Meier survival curves were constructed to determine the prognosis, cyclin E, p27 and mutant p53 expressions did not predict poor prognosis. CONCLUSIONS: Our results suggested that the expression of cyclin E, p27 and mutant p53 proteins did not predict the clinical outcome in the stage II colorectal carcinomas.  相似文献   
44.
45.
46.
A 25-year-old female has had brown to erythematous telangiectatic patches and grouped papules on her face, neck, arm, and trunk since childhood following B.C.G. vaccination. Histopathologically, the lesions consisted of hyperkeratosis, slight acanthosis, tuberculoid granulomas with some Langerhans type giant cells in the mid-dermis. Although various forms of cutaneous tuberculosis after B.C.G. vaccination have been reported, it was difficult for us to assign the patient's skin lesion to any specific disease entity. Remission of her cutaneous lesions occurred clinically and histopathologically after treatment with isoniazid and rifampin.  相似文献   
47.
48.
49.
Although adenocarcinoma is a well known complication of chronic inflammatory bowel disease, primary gastrointestinal lymphoma occurring in Crohn's disease is rare. A 40-year-old man with 10 year-history of Crohn's disease had multiple longitudinal ulcerative lesions on descending colon in follow-up colonoscopic examination. Microscopic examination of proximal descending colon revealed peripheral T cell lymphoma and other site of the descending colon was consistent with Crohn's disease. The patient reached complete remission of malignant lymphoma after three cycles of combined chemotherapy. He has been well for 10 months with sulfasalazine maintenance therapy but was admitted to the hospital due to spontaneous bowel perforation of ascending colon. Right hemicolectomy was done, but the patient died of post-surgical recurrent mesenteric abscess and sepsis. To the best of our knowledge, this is the first case of Non-Hodgkin's lymphoma complicating Crohn's disease in Korea which was confirmed by immunohistochemical studies.  相似文献   
50.
Recent investigations have shown that the calcium channel blocker verapamil attenuated the hypoxic ventilatory chemosensitivity of carotid body in animals. To determine whether this is also the case in humans, transient physiological chemodenervation by O2 breaths (withdrawal test) during sustained hypoxia (N = 7), and ventilatory and circulatory responses to progressive hypoxia and hypercapnia (N = 8) were examined after oral administration of verapamil. During sustained hypoxia after verpamil, there was a significant reduction of withdrawal response from 5th to 25th min value (p < 0.01), but not after placebo. On the other hand, no significant difference in ventilatory responses to progressive hypoxia and hypercapnia was observed after verapamil. Verapamil run reveals similar features with placebo run in circulatory parameters except blood pressure response, which tended to be suppressed by verapamil. We conclude that verapamil attenuates peripheral chemoreceptor activity with time during sustained mild hypoxia in normal adult humans and this may be explained by delayed depletion in intracellular Ca2+ for chemotransduction of the peripheral chemoreceptors.  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