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   10258篇
  免费   427篇
  国内免费   74篇
耳鼻咽喉   208篇
儿科学   290篇
妇产科学   119篇
基础医学   1536篇
口腔科学   176篇
临床医学   556篇
内科学   2638篇
皮肤病学   179篇
神经病学   677篇
特种医学   444篇
外科学   1682篇
综合类   43篇
一般理论   2篇
预防医学   185篇
眼科学   127篇
药学   632篇
中国医学   26篇
肿瘤学   1239篇
  2023年   58篇
  2022年   121篇
  2021年   254篇
  2020年   126篇
  2019年   164篇
  2018年   212篇
  2017年   175篇
  2016年   201篇
  2015年   188篇
  2014年   275篇
  2013年   365篇
  2012年   572篇
  2011年   671篇
  2010年   387篇
  2009年   289篇
  2008年   495篇
  2007年   585篇
  2006年   592篇
  2005年   615篇
  2004年   651篇
  2003年   604篇
  2002年   685篇
  2001年   188篇
  2000年   142篇
  1999年   159篇
  1998年   156篇
  1997年   145篇
  1996年   127篇
  1995年   94篇
  1994年   113篇
  1993年   109篇
  1992年   104篇
  1991年   96篇
  1990年   95篇
  1989年   95篇
  1988年   89篇
  1987年   70篇
  1986年   78篇
  1985年   63篇
  1984年   62篇
  1983年   44篇
  1982年   40篇
  1981年   31篇
  1980年   33篇
  1979年   30篇
  1978年   37篇
  1974年   28篇
  1973年   26篇
  1972年   29篇
  1971年   29篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
A new operative procedure was devised to treat polysyndactyly of the fifth toe. This procedure, which consists of removal of the fifth toe, correction of the alignment of the preserved sixth toe by arthroplasty and construction of an interdigital space by Z-plasty, is technically simple and produces good results, both functionally and aesthetically.  相似文献   
32.
Summary To study the effects of family history and reproductive, anthropometric, and dietary factors on the risk of breast cancer among low risk populations, we conducted a hospital-based case-control study involving 908 patients with breast cancer and their matched controls, in Japan. A positive family history of breast cancer significantly increased the risk of breast cancer (odds ratio = 1.52, 95% confidence interval: 1.14–2.03). The risk further increased with increasing number of family members affected. Obesity, single marital status, fewer births, a late childbirth, and less consumption of green-yellow vegetables and dairy products were also associated with an increased risk of breast cancer. These associations were independent in multivariate analyses. There was no increase in risk associated with consumption of high fat foods. When analyzed by menopausal status, the association with family history of breast cancer, especially in the first degree of relatives, was more evident for premenopausal breast cancer. The associations with obesity and lower consumption of dairy products were more pronounced for postmenopausal breast cancer, while those with lower parity and single marital status were stronger for premenopausal breast cancer.  相似文献   
33.
A Japanese girl was referred to Osaka University Dental Hospital for examination of a tooth-like structure that had erupted following spontaneous exfoliation of a natal tooth in the lower left primary central incisor region. The structure had erupted at 6 months of age, and radiographic and clinical examination showed composition of pulp and dentin, but no enamel. On histological examination, the majority of the dentin area had a tubular dentin-like appearance, while the outer area of the root appeared to be composed of an osteodentin-like substance. Most of the dentin was covered by cementum. These findings suggest that the structure had originated from a developing remnant of the extracted natal tooth, which must have remained in the gingival tissues. We termed this calcified structure a residual natal tooth.  相似文献   
34.
We performed laparoscopic appendectomy and drainage to treat panperitonitis due to perforated appendicitis that occurred in a 28‐year‐old woman. We believe this is an appropriate procedure to treat perforated appendicitis because it is safe and minimally invasive, and faster recovery can be expected than after conventional open appendectomy.  相似文献   
35.
In order to investigate whether a hypothalamic disorder cause hypogonadism in male prolactinomas, LH pulsatile secretion was studied in 13 male patients. Serum PRL levels ranged from 186 to 45,000 ng ml-1 before treatment, and all the tumors were macroadenomas. Reduced LH secretion was revealed in 5 of 13 patients, and FSH was reduced in 1 of 13. Serum testosterone (T) levels were lower than the normal limit in all the patients. HCG tests in 3 patients showed good responses, but the peak values of T were lower than those of normal men. LH pulsatilities were examined in 5 hyperprolactinemic patients before treatment, in 4 hyperprolactinemic patients after operation, and in 8 normoprolactinemic patients after operation and/or bromocriptine treatment. There was no significant difference of the mean LH values, the frequencies of LH pulses, and amplitudes among the hyperprolactinemic patients before operation (n = 5), the normoprolactinemic patients after operation (n = 8), and normal men (n = 7). From these results, it was evident that the hypothalamus and pituitary function of male prolactinomas were well preserved, in spite of higher serum PRL levels and larger tumor size than those reported in females. It is suggested that the main cause of hypogonadism in these patients is due to testicular dysfunction resulting from excessive serum PRL.  相似文献   
36.
Fibrate for treatment of primary biliary cirrhosis   总被引:1,自引:0,他引:1  
Recent studies of the effectiveness of ursodeoxycholic acid (UDCA) therapy in patients with primary biliary cirrhosis (PBC) reported that UDCA therapy did not necessarily stop the progression of liver fibrosis in all patients, even those with early stage PBC. Thus, there is a need for more effective treatments that could prevent asymptomatic PBC from progressing to the icteric stage. Bezafibrate is effective in approximately two-thirds of non-icteric patients who have not shown a complete response to UDCA. Serum bilirubin, aspartate aminotransferase and γ-guanosine 5'-triphosphate levelswere significantly lower in patients who responded to additional bezafibrate on univariate analysis. The putative mechanism by which bezafibrate acts in cholestasis is by increasing phospholipid output into bile, which forms micelles with the hydrophobic bile acid that reduces its toxicity.  相似文献   
37.
Hypertrophic scars (HS) are a consequence of abnormal wound healing. We examined fatty acids that are contained within, and participate in, every reaction through the membrane; then, we analyzed the percentage composition of the fatty acids in deepithelialized normal dermis (ND) and HS. In vivo HS samples were obtained from six patients undergoing surgical excision, and ND samples from five patients undergoing skin grafting surgery for excess. In vitro, cultured fibroblasts from HS and ND were also analyzed. The percentage composition of fatty acids extracted from all the samples was analyzed. In vivo, arachidonic acid (20:4) was significantly more abundant in HS than in ND, in the phospholipids from both whole tissue and cell membranes. In vitro, there were no significant differences among ND, HS, and 10% fetal calf serum. The results suggest that HS formation does not necessarily involve simple excess of 20:4; however, there are considerable differences in the percentage composition of 20:4 between ND and HS. Arachidonic acid probably participates in the formation and maintenance of HS, whereas in vitro cultured fibroblasts are affected largely by fetal calf serum.  相似文献   
38.
A 57-year-old man with a history of renal cell carcinoma presented with presyncope. He underwent nephrectomy years earlier followed by HLA-matched allogeneic peripheral-blood stem-cell transplantation. Echocardiographic investigation revealed a solitary right ventricle mass without contiguous vena caval or right atrial involvement. The mass was pathologically confirmed to be metastatic carcinoma in the right ventricular cavity. This case highlights the need to consider an underlying neoplastic syndrome in patients presenting isolated right ventricle mass by echocardiography.  相似文献   
39.
40.
Previous studies using primary monolayer cultures of epithelial cells from the involved epidermis of patients with mammary and extramammary Paget's disease investigated whether Paget cells proliferate as other malignant cells do. Although epithelial monolayers from the involved skin were maintained for approximately 45 days, no permanent cell lines were established. The proportion of carcinoembryonic antigen (CEA)-positive cells did not increase in the long-term cultures. Herein, we report studies of whether there is a real reduction of Paget cell numbers or if this is merely a decrease in the expression of CEA by the cells. Furthermore, we investigated whether Paget cells survive longer when cultured free from any potential inhibitory keratinocytes or other epidermal cells. Skin samples were obtained from one patient with mammary Paget's disease and three with extramammary Paget's disease; epidermal cells were cultured in vitro. An enrichment of Paget cells was carried out from the cultured epidermal cells by combining an anti-epithelial membrane antigen monoclonal antibody, binding to immunobeads, and density gradient centrifugation in Nycodenz. The separated cells were re-cultured in Keratinocyte-SFM serum-free media. The proportion of CEA-positive cells did not increase in the cultures, and the purified cells did not show any increase in survival times compared to the non-purified cultured cells. These results suggest that the decrease of CEA-positive cells noted during culture results from a decline in expression of CEA in the Paget cells. Paget cells in the involved epidermis do not proliferate significantly and thus differ from many other malignant cells.  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