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   936309篇
  免费   66536篇
  国内免费   1370篇
耳鼻咽喉   12975篇
儿科学   24444篇
妇产科学   23283篇
基础医学   133429篇
口腔科学   28329篇
临床医学   80886篇
内科学   184326篇
皮肤病学   19301篇
神经病学   72572篇
特种医学   36992篇
外国民族医学   79篇
外科学   152818篇
综合类   18059篇
现状与发展   1篇
一般理论   234篇
预防医学   61857篇
眼科学   21392篇
药学   72888篇
  3篇
中国医学   2173篇
肿瘤学   58174篇
  2018年   9073篇
  2017年   7094篇
  2016年   7857篇
  2015年   8954篇
  2014年   12094篇
  2013年   17666篇
  2012年   24348篇
  2011年   25260篇
  2010年   14929篇
  2009年   14382篇
  2008年   24840篇
  2007年   25923篇
  2006年   26720篇
  2005年   25649篇
  2004年   24785篇
  2003年   23800篇
  2002年   23358篇
  2001年   54840篇
  2000年   56631篇
  1999年   47043篇
  1998年   10783篇
  1997年   9522篇
  1996年   9630篇
  1995年   8971篇
  1994年   8318篇
  1993年   7627篇
  1992年   35556篇
  1991年   33981篇
  1990年   32802篇
  1989年   31940篇
  1988年   29049篇
  1987年   28305篇
  1986年   26360篇
  1985年   25194篇
  1984年   17877篇
  1983年   15167篇
  1982年   7811篇
  1981年   6786篇
  1979年   15804篇
  1978年   10617篇
  1977年   9073篇
  1976年   7881篇
  1975年   8652篇
  1974年   10481篇
  1973年   9872篇
  1972年   9366篇
  1971年   8878篇
  1970年   8439篇
  1969年   7940篇
  1968年   7220篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
    
Head and neck radiology instead of the Diagnostic Neuroradiology section. The editors apologise for any confusion this may have caused.  相似文献   
992.
The talar beak is a well-described secondary sign of talocalcaneal coalition but is not pathognomonic of the condition and may be seen in other causes of restricted or abnormal subtalar motion. We present an unusual complication of talar beaks in two patients who sustained fractures through their beaks. One of the patients described did not have a talocalcaneal coalition but had developed a beak following a compound fracture dislocation of the ankle joint complicated by infection, a previously undescribed predisposing cause.  相似文献   
993.
We have introduced and evaluated several modifications of the conventional venovenous bypass (VVBP) in 29 adult patients undergoing liver transplantation (OLT). A percutaneous technique for insertion of a jugular venous return cannula and a femoral vein cannula was applied. The inferior mesenteric vein (IMV) was used for splanchnic decompression, which facilitated dissection of the recipient liver and allowed portal anastomosis to be performed without disconnecting the portal bypass. A heat exchanger was introduced into the bypass circuit to prevent heat loss. The percutaneous technique prevented complications related to dissection in the axilla and groin. Hemodynamic characteristics corresponded to those found using the traditional technique. Complications related to the VVBP were seen in only one patient in whom the femoral catheter was accidentally introduced into the femoral artery. We conclude that percutaneous cannulas, use of the IMV for splanchnic decompression and the introduction of a heat exchanger offer significant benefits and that they are safe and reliable. Received: 23 August 1996 Received after revision: 14 January 1997 Accepted: 27 January 1997  相似文献   
994.
Knife injuries can be classified into stabbing injuries and multiple laceration or multiple chops, the latter being much more common in Chinese communities. It is the mark of criminal gang attacks with their tendency to use long knives and choppers rather than guns. The intention is often to wound rather than kill. A survey of 89 cases revealed that 90% of the victims are men, with a mean age of 27 years; 75% was admitted to the hospital at night, and in 78% of the cases the assailants were persons unknown, or so we were told by the victims. The reasons for the attacks were also not given. Most of the women victims were assaulted by their spouse. Some 74% of the patients suffered three to six lacerations; 62% of the injuries were on the extensor surfaces of the upper limbs, while the hand and the back of the trunk were also common sites. The type of management differs from that for stabbing injuries. There were no fatalities, and less than half of the patients required blood transfusion. The average hospital stay was 6.2 days. The morbidity of these injuries involves damaged tendons and nerves.  相似文献   
995.
Spinal cord compression is an extremely serious complication of hereditary multiple exostoses (HME). A case of HME with compression of the cervical spinal cord is reported. Complete recovery following surgery was achieved. A review of the relevant literature revealed 51 previous cases of HME with cord/cauda equina compression. Most patients were under 30 years of age with more men affected than women. The family history was positive in 60%. The cervical and thoracic areas were predominantly affected, with the symptoms usually developing slowly. Recovery following surgery is to be expected in the majority of cases. In patients with HME and suffering from neurological symptoms, the possibility of spinal cord compression should be considered. Prompt diagnosis and surgical excision provide the best prognosis.  相似文献   
996.
Distortion of the knee joint is a considerable trauma even when the knee is primarily stable. Of 50 patients 30% displayed symptoms or signs 2 months after the injury and 36% on subsequent examination an average of 5.6 years later. In a repeat clinical examination one anterior cruciate ligament rupture was not confirmed at the primary stage (2%). For assessment of stability and extent of injury, the repeat clinical examination proved reliable. Ruptures of the meniscus were noted in 18% of the patients in connection with the primary injury. Of those who underwent a meniscus operation, 27% had further operations and, four patients of 50 had another operation as a result of a new trauma. Thus, a total of 25% of the patients required surgery. The material is biased as I sought to exclude ligament ruptures in the first instance. No patient was permanently incapacitated from work. A large portion of the later symptoms were connected with the patellofemoral joint or with the postoperative condition. Bandaging did not affect the resulting recovery rate. Regular exercise of the thigh muscles prevented the onset of quadriceps atrophy, but there was a clear deterioration in the condition of the muscles in the early stages.  相似文献   
997.
Staging of esophageal carcinoma in vitro with 4.7-T MR imaging   总被引:4,自引:0,他引:4  
  相似文献   
998.
999.
A number of the culture filtrate proteins secreted by Mycobacterium tuberculosis are known to contribute to the immunology of tuberculosis and to possess enzymatic activities associated with pathogenicity. However, a complete analysis of the protein composition of this fraction has been lacking. By using two-dimensional polyacrylamide gel electrophoresis, detailed maps of the culture filtrate proteins of M. tuberculosis H37Rv were generated. In total, 205 protein spots were observed. The coupling of this electrophoretic technique with Western blot analysis allowed the identification and mapping of 32 proteins. Further molecular characterization of abundant proteins within this fraction was achieved by N-terminal amino acid sequencing and liquid chromatography-mass spectrometry. Eighteen proteins were subjected to N-group analysis; of these, only 10 could be sequenced by Edman degradation. Among the most interesting were a novel 52-kDa protein demonstrating significant homology to an alpha-hydroxysteroid dehydrogenase of Eubacterium sp. strain VPI 12708, a 25-kDa protein corresponding to open reading frame 28 of the M. tuberculosis cosmid MTCY1A11, and a 31-kDa protein exhibiting an amino acid sequence identical to that of antigen 85A and 85B. This latter product migrated with an isoelectric point between those of antigen 85A and 85C but did not react with the antibody specific for this complex, suggesting that there is a fourth member of the antigen 85 complex. Novel N-terminal amino acid sequences were obtained for three additional culture filtrate proteins; however, these did not yield significant homology to known protein sequences. A protein cluster of 85 to 88 kDa, recognized by the monoclonal antibodies IT-57 and IT-42 and known to react with sera from a large proportion of tuberculosis patients, was refractory to N-group analysis. Nevertheless, mass spectrometry of peptides obtained from one member of this complex identified it as the M. tuberculosis KatG catalase/peroxidase. Thus, the detailed mapping of M. tuberculosis proteins, combined with state-of-the-art analytical techniques such as mass spectrometry, provides a basis for further analysis and rapid identification of biologically relevant molecules.  相似文献   
1000.
A total of 113 patients underwent a cemented total hip replacement (THR) operation involving femoral component fixation either without the use of a distal intramedullary plug (n = 57, group 1) or with the plug (n =56, group 2). We studied the femoral component fixation radiographically at on average 6 years after THR. The cement coating was assessed as technically good in 86% and 95% of groups 1 and 2, respectively. There was radiographically diagnosable loosening of the femoral component at the follow-up in 25 cases in which stems were inserted without the intramedullary plug, and in 6 cases in those with the plug (P < 0.0008), and the mean subsidence of the femoral component was 5 mm in group 1 and 1.5 mm (P < 0.0003) in group 2, respectively. Osteolytic changes around the femoral component were noticed in both groups in equal numbers and with no statistical difference. The use of a distal intramedullary plug in the cementation of the femoral stem results in a better cement coating, reduces femoral component subsidence and ameliorates the loosening rates.  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