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   675篇
  免费   38篇
  国内免费   20篇
耳鼻咽喉   2篇
儿科学   29篇
妇产科学   7篇
基础医学   48篇
口腔科学   26篇
临床医学   140篇
内科学   144篇
皮肤病学   2篇
神经病学   12篇
特种医学   164篇
外科学   51篇
综合类   24篇
预防医学   25篇
药学   25篇
肿瘤学   34篇
  2023年   6篇
  2022年   2篇
  2021年   10篇
  2020年   2篇
  2019年   3篇
  2018年   5篇
  2017年   6篇
  2016年   9篇
  2015年   5篇
  2014年   16篇
  2013年   25篇
  2012年   15篇
  2011年   25篇
  2010年   26篇
  2009年   44篇
  2008年   15篇
  2007年   15篇
  2006年   9篇
  2005年   13篇
  2004年   3篇
  2003年   13篇
  2002年   12篇
  2001年   18篇
  2000年   15篇
  1999年   10篇
  1998年   40篇
  1997年   38篇
  1996年   37篇
  1995年   35篇
  1994年   22篇
  1993年   25篇
  1992年   7篇
  1991年   5篇
  1990年   8篇
  1989年   25篇
  1988年   24篇
  1987年   15篇
  1986年   9篇
  1985年   16篇
  1984年   10篇
  1983年   8篇
  1982年   20篇
  1981年   13篇
  1980年   20篇
  1979年   4篇
  1978年   8篇
  1977年   11篇
  1976年   7篇
  1975年   3篇
  1974年   1篇
排序方式: 共有733条查询结果,搜索用时 62 毫秒
31.
0 引言 腹泻标本中同时检出类志贺邻单胞菌和豚鼠气单胞菌 ,在国内尚未见报道 .现报告如下 .1 临床资料 患者 ,女 ,45岁 .主诉于 12 h前因食不洁冷冻鱼类食品后 ,出现腹痛伴腹泻 ,为黄色稀水便转为血水样便 ,9次 / d,每次量约 2 0 0 m L.伴轻度乏力、恶心、里急后重 .腹痛以上腹部及左下腹部为著 ,呈持续隐痛伴有阵发性加重 .于2 0 0 0 - 0 3- 2 7就诊 .体检 :T37.2℃ ,P78次 / min,R16次 /min,BP13/ 8KPa.实验室检查 :WBC10 .8× 10 9· L- 1 ,N0 .84,L 0 .16 .大便常规 :RBC +++/ HP,WBC 3- 9/ HP,便隐血阳性 .取粪便送检做…  相似文献   
32.
Background Merkel cell carcinoma (MCC) is a rare malignant cutaneous tumour, the incidence of which is increasing. Second malignancies have been reported to occur with high incidence in these patients. Objectives We report the rate and nature of multiple malignancies in patients with MCC treated over a 10 year period in Addenbrooke’s Hospital in Cambridge, United Kingdom, as well as the temporal relationship of these additional malignancies to the diagnosis of MCC. Results The 27 patients had an approximately equal sex incidence with a median age at diagnosis of 79 years. Seventy percent (n=19) of patients had a second primary malignant tumour; and 7 of these patients had two or more tumours in addition to the MCC. Eighteen patients had additional cutaneous malignancies: melanoma, squamous cell carcinoma and basal cell carcinoma, and 8 patients presented non‐cutaneous malignancy including colorectal, haematological and breast tumours. Of the 28 additional tumours in our patients, half were diagnosed prior to presentation of MCC, 32% within 6 months of diagnosis, and 18% between 6 months and 3 years after diagnosis. Possible reasons for the high rate of additional tumours in this population are discussed. Conclusions Our figures reflect a higher incidence of multiple malignancies in those with Merkel cell tumour than has previously been reported. This has important implications for the care and surveillance of these patients.  相似文献   
33.
34.
35.
36.
A baby with unilateral cleft lip, midline cleft palate and hypertelorism developed meningitis in the first 48 h of life. Examination of the nasopharynx showed a soft tissue mass, which was confirmed as a basal encephalocele by computed tomography. There was also congenital hydrocephalus and the corpus callosum was absent. Surgical treatment included repair of the anterior basal skull defect, repair of the lip and palate, and ventriculo-peritoneal shunt. There is currently evidence of developmental delay and right-sided visual impairment due to Morning Glory syndrome. This case demonstrates that basal encephalocele should be considered in any baby with midline facial deformity who develops meningitis.  相似文献   
37.
Stress fractures are common overuse injuries seen in athletes and military recruits. The pathogenesis is multifactorial and usually involves repetitive submaximal stresses. Intrinsic factors, such as hormonal imbalances, may also contribute to the onset of stress fractures, especially in women. The classic presentation is a patient who experiences the insidious onset of pain after an abrupt increase in the duration or intensity of exercise. The diagnosis is primarily clinical, but imaging modalities such as plain radiography, scintigraphy, computed tomography, and magnetic resonance imaging may provide confirmation. Most stress fractures are uncomplicated and can be managed by rest and restriction from the precipitating activity. A subset of stress fractures can present a high risk for progression to complete fracture, delayed union, or nonunion. Specific sites for this type of stress fracture are the femoral neck (tension side), the patella, the anterior cortex of the tibia, the medial malleolus, the talus, the tarsal navicular, the fifth metatarsal, and the great toe sesamoids. Tensile forces and the relative avascularity at the site of a stress-induced fracture often lead to poor healing. Therefore, high-risk stress fractures require aggressive treatment.  相似文献   
38.
Moser  GJ; Wolf  DC; Wong  BA; Goldsworthy  TL 《Carcinogenesis》1997,18(5):1075-1083
Unleaded gasoline (UG) vapor (2056 ppm) increased the incidence of liver tumors in a chronic bioassay and exhibited tumor-promoting activity in N-nitrosodiethylamine (DEN)-initiated female mouse liver. Estrogen inhibited mouse liver tumor development and the hepatocarcinogenic and tumor-promoting dose of UG produced uterine changes suggestive of estrogen antagonism. To directly test the hypothesis that UG-induced tumor-promoting ability is secondary to its interaction with the mouse liver tumor inhibitor, estrogen, we compared the tumor-promoting ability of UG in ovariectomized (Ovex) mice with the hepatic tumor-promoting ability of UG in intact mice. Ovaries were surgically removed at 4 weeks of age. Exposure to wholly vaporized UG (2018 ppm) under bioassay and tumor-promoting conditions began at 8 weeks of age. After 4 months of exposure, UG increased relative liver weight and hepatic microsomal cytochrome P450 pentoxyresourfin-O- dealkylase and ethoxyresorufin-O-deethylase activity to a similar extent in intact and Ovex mice. Non-focal hepatocyte proliferation, as measured by the incorporation of bromo-deoxyuridine, was not changed by UG exposure and was similar in all treatment groups. After 4 months of exposure to DEN-initiated mice, UG significantly increased the volume fraction of liver occupied by foci (three-fold) as compared to control intact mice. As expected, volume of foci was elevated in DEN/Ovex/control mice as compared to DEN/intact/control mice. In DEN/Ovex mice UG did not significantly increase the focal volume fraction. Thus, the tumor promoting activity of UG, as demonstrated by increased volume fraction of liver occupied by hepatic foci in intact mice, is greatly attenuated in Ovex mice. The volume fraction data in Ovex mice support the hypothesis that the tumor promoting activity of UG is dependent upon the interaction of UG with ovarian hormones. These data also indicate that hepatic microsomal cytochrome P450 PROD and EROD induction, hepatomegaly and non-focal hepatic LI are not specific markers of hepatic tumor promoting activity of UG.   相似文献   
39.
Transgenic mice with both alleles of the p53 tumor suppressor gene product 'knocked out' by gene targeting are susceptible to early development of tumors, chiefly lymphomas and sarcomas. Compared with the control group, administration of dehydroepiandrosterone (DHEA) at 0.3% of the diet to male p53-deficient mice extended their lifespan by delaying death due to neoplasms (from 105 to 166 days on study, P = 0.002), primarily by suppressing lymphoblastic lymphoma (from 45 to 6% of neoplastic deaths, P = 0.010). Treatment with a synthetic DHEA analog, 16alpha-fluoro-5-androsten-17-one (compound 8354), at 0.15% of the diet also increased lifespan, to 140 days for mice that developed tumors (P = 0.037). The effects of these steroids on lifespan and tumor development did not appear to be strongly related to inhibition of food consumption and weight gain, in that a group pair-fed with control diet to the reduced food consumption of the DHEA-treated group developed and died of the same types of neoplasms at the same rate as the controls fed ad libitum. The chemopreventive effect of these steroids has been proposed to be due to suppression of DNA synthesis by inhibition of glucose 6-phosphate dehydrogenase, the rate-limiting enzyme of the pentose phosphate pathway. Although DHEA and its analog are strong non- competitive inhibitors of this enzyme in vitro, treatment with DHEA did not deplete cellular nucleotide pools in the liver, as would have been predicted. The chemopreventive effect of DHEA in this model may be due to steroid-induced thymic atrophy and suppression of T cell lymphoma, permitting these mice to survive long enough to develop tumors with longer latency.   相似文献   
40.
Hemolytic uremic syndrome spontaneously arises in a few patients with advanced cancer, but it is more commonly related to the use of certain chemotherapeutic agents. Mitomycin-C is, etiologically, the most common causative agent inducing hemolytic uremic syndrome, in a dose dependent manner. We report this syndrome, attributable to mitomycin-C at a cumulative dose of 40 mg/m2, in a gastric cancer patient. A 42-year-old female with stage III gastric cancer underwent radical gastrectomy and was given mitomycin-C at 10 mg/m2 intravenously every four weeks as adjuvant therapy. Hemolytic uremic syndrome was diagnosed three months after the last dose of mitomycin-C administration. The most prominent symptoms included pallor, hypertension and anasarca, with laboratory evidence of microangiopathic hemolytic anemia, azotemia and hyperkalemia. Her disease was progressive, but fortunately stabilized after staphylococcus column A dialysis. Her disease remained in remission for 24 months from the time of diagnosis, and then relapsed in the form of peritoneal carcinomatosis with partial intestinal obstruction.   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