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   20824篇
  免费   1071篇
  国内免费   122篇
耳鼻咽喉   144篇
儿科学   301篇
妇产科学   182篇
基础医学   2617篇
口腔科学   514篇
临床医学   1513篇
内科学   5433篇
皮肤病学   298篇
神经病学   1502篇
特种医学   746篇
外科学   3957篇
综合类   58篇
预防医学   529篇
眼科学   295篇
药学   1348篇
中国医学   22篇
肿瘤学   2558篇
  2023年   124篇
  2022年   273篇
  2021年   451篇
  2020年   256篇
  2019年   352篇
  2018年   429篇
  2017年   360篇
  2016年   416篇
  2015年   428篇
  2014年   529篇
  2013年   650篇
  2012年   1044篇
  2011年   1054篇
  2010年   639篇
  2009年   520篇
  2008年   933篇
  2007年   890篇
  2006年   954篇
  2005年   959篇
  2004年   947篇
  2003年   940篇
  2002年   946篇
  2001年   672篇
  2000年   685篇
  1999年   626篇
  1998年   306篇
  1997年   230篇
  1996年   188篇
  1995年   173篇
  1994年   147篇
  1993年   163篇
  1992年   547篇
  1991年   507篇
  1990年   461篇
  1989年   434篇
  1988年   348篇
  1987年   322篇
  1986年   305篇
  1985年   263篇
  1984年   174篇
  1983年   163篇
  1982年   66篇
  1979年   140篇
  1978年   95篇
  1977年   80篇
  1975年   65篇
  1974年   86篇
  1973年   73篇
  1972年   79篇
  1971年   73篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
We analyzed the determinant factors as to whether open heart surgery with non-blood transfusion may be indicated or not, according to the formula based on the quantitative theory (class II). Extracorporeal circulation with non-blood priming were indicated on 106 patients using Cell Saver apparatus in our department, they were divided into two groups; blood transfusion group (group I): 38 patients, and non-blood transfusion group (group II): 68 patients. These two groups were compared for study in terms of age, preoperative body weight (BW), the body surface area (BSA), preoperative Hct value (Hct), calculated Hct value (Hct(C)) at the start of extracorporeal circulation (ECC), the aortic cross-clamping time (AXT), the total extracorporeal circulation time (TECCT) and total bleeding amount. The followings are described in the ranking of importance. 1) The amount of blood loss in ICU: less than 400 ml. 2) Hct(C): more than 30%. 3) The amount of blood loss after ECC: less than 130 ml. 4) Hct: more than 40%. 5) BW: more than 55 kg. 6) The total bleeding amount: less than 600 ml. 7) TECCT: less than 90 min. 8) AXT: less than 50 min. In addition, prospective factors which should be considered preoperatively are determined in the following ranking. 1) Hct. 2) Hct(C). 3) BW. From these results, the amount of blood loss in ICU, Hct and Hct(C) were found to be reliable critical in any case as determinant factors for open heart surgery with non-blood transfusion.  相似文献   
93.
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   
94.
A stable cell line, KHM-3S, was established from a patient with small cell lung cancer (SCLC), who had a high serum level of soluble interleukin 2 receptors (sIL2-R) and was seropositive for human T cell leukemia virus (HTLV)-l. KHM-3S cells were positive for IL2-R (Tac) and NKH-1, but negative for other lymphocytic markers such as OKT 11, OKT 4, OKT 8, T cell receptor (WT 31), B 1, and B 4. Moreover, the KHM-3S cells were negative for leukocyte common antigen and strongly positive for neuron-specific enolase (NSE). Secretion of sIL2-R and NSE by the KHM-3S line was detected by an enzyme-linked immunosorbent assay. Rearrangement of the T cell receptor gene and monoclonal HTLV-1 integration were found by Southern blot analysis of KHM-3S DNA. However, Northern blot analysis showed no T cell receptor mRNA. KHM-3S may be useful for studies on the role of HTLV-1 in carcinogenesis and IL2-R expression in SCLC.  相似文献   
95.
96.
97.
98.
Electrogastrograms (EGGs) were recorded in patients both before and after receiving proximal gastrectomy plus jejunal interposition (PGJI) or just after receiving total gastrectomy plus jejunal interposition (TGJI). Intraluminal pressure was also recorded in some postoperative patients. The EGG 3 cpm component (2.5-4.9 cpm) remained after PGJI, but subsequently decreased with a significant reduction in the preoperative to postoperative ratio of the 3 cpm components (P<0.05). The mean frequency of the 3 cpm components increased significantly after PGJI (P<0.05) and its instability factor increased. The EGG 10 cpm components became relatively dominant compared to other frequency components in 2 out of 8 of patients having PGJI but the mean amplitude of 10 cpm decreased. In TGJI patients, only the 10 cpm component was conspicuous in EGG as in the case of total gastrectomy and Roux en Y anastomosis procedures. The spectral frequencies of intraluminal pressure in the interposed jejunum were similar to the EGG of 10 cpm components both in the case of PGJI and TGJI patients. In conclusion, surface EGG could record the electrical activities of the interposed jejunum more easily in patients having had TGJI than in PGJI.  相似文献   
99.
Papillary fibroelastoma (PFE) is a rare and benign cardiac tumor typically found on the valvular endocardium. In most cases, PFE is identified incidentally on echocardiography or during cardiac surgery. The patient was a 73-year-old man who had been treated for hepatocellular carcinoma for 5 years. On echocardiography, a 2.5-cm diameter mass was detected in the pulmonary trunk just above the pulmonary valve. Through a transpulmonary arterial approach with cardiopulmonary bypass, the mass identified on the commissure of the right and posterior pulmonary cusp was surgically excised together with the attached endocardium. Despite the benign histology of PFE, lethal embolic events such as stroke, myocardial infarction, and pulmonary embolism are reported in some cases. To prevent such complications, tumor identification and surgical excision are essential.  相似文献   
100.
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