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   5724篇
  免费   220篇
  国内免费   29篇
耳鼻咽喉   34篇
儿科学   103篇
妇产科学   51篇
基础医学   561篇
口腔科学   78篇
临床医学   359篇
内科学   1441篇
皮肤病学   107篇
神经病学   485篇
特种医学   159篇
外科学   1115篇
综合类   23篇
预防医学   157篇
眼科学   115篇
药学   394篇
中国医学   11篇
肿瘤学   780篇
  2023年   28篇
  2022年   55篇
  2021年   93篇
  2020年   66篇
  2019年   65篇
  2018年   90篇
  2017年   87篇
  2016年   100篇
  2015年   126篇
  2014年   146篇
  2013年   211篇
  2012年   293篇
  2011年   402篇
  2010年   202篇
  2009年   177篇
  2008年   323篇
  2007年   425篇
  2006年   422篇
  2005年   399篇
  2004年   397篇
  2003年   416篇
  2002年   451篇
  2001年   45篇
  2000年   59篇
  1999年   63篇
  1998年   132篇
  1997年   82篇
  1996年   85篇
  1995年   59篇
  1994年   53篇
  1993年   48篇
  1992年   37篇
  1991年   45篇
  1990年   38篇
  1989年   32篇
  1988年   24篇
  1987年   27篇
  1986年   17篇
  1985年   21篇
  1984年   18篇
  1983年   11篇
  1982年   9篇
  1981年   12篇
  1980年   19篇
  1979年   10篇
  1978年   9篇
  1977年   11篇
  1975年   6篇
  1974年   6篇
  1971年   4篇
排序方式: 共有5973条查询结果,搜索用时 14 毫秒
31.
32.
33.
Tranexamic acid (TXA) reduces the risk of bleeding trauma death without altering the need for blood transfusion. We examined the effects of TXA on coagulation and fibrinolysis dynamics and the volume of transfusion during the early stage of trauma. This subanalysis of a prospective multicenter study of severe trauma included 276 patients divided into propensity score–matched groups with and without TXA administration. The effects of TXA on coagulation and fibrinolysis markers immediately at (time point 0) and 3 hours after (time point 3) arrival at the emergency department were investigated. The transfusion volume was determined at 24 hours after admission. TXA was administered to the patients within 3 hours (median, 64 minutes) after injury. Significant reductions in fibrin/fibrinogen degradation products and D-dimer levels from time points 0 to 3 in the TXA group compared with the non-TXA group were confirmed, with no marked differences noted in the 24-hour transfusion volumes between the 2 groups. Continuously increased levels of soluble fibrin, a marker of thrombin generation, from time points 0 to 3 and high levels of plasminogen activator inhibitor-1, a marker of inhibition of fibrinolysis, at time point 3 were observed in both groups. TXA inhibited fibrin(ogen)olysis during the early stage of severe trauma, although this was not associated with a reduction in the transfusion volume. Other confounders affecting the dynamics of fibrinolysis and transfusion requirement need to be clarified.  相似文献   
34.
35.
The purple-flesh potato (Solanum tuberosum L.) cultivar “Shadow Queen” (SQ) naturally contains anthocyanins. This randomized, double-blind, placebo-controlled study determines whether ingesting purple potatoes increases the number of mesenchymal stem cells (MSC) and improves stress response, a minor health complaint in healthy adults (registration number: UMIN000038876). A total of 15 healthy subjects (ages: 50–70 years) with minor health complaints were randomly assigned to one of two groups. For 8 weeks, the placebo group received placebo potatoes cv. “Haruka” and the test group received test potato cv. SQ containing 45 mg anthocyanin. The MSC count and several stress responses were analyzed at weeks 0 and 8 of the intake periods. The ingestion of a SQ potato did not affect the MSC count but markedly improved psychological stress response, irritability, and depression as minor health complaints compared with “Haruka”. No adverse effects were noted. Hence, an 8-week intake of SQ could improve stress responses.  相似文献   
36.
Chylous ascites (CA) is the accumulation of fluid with a high triglyceride content in the peritoneal cavity. Only two cases in the literature have reported CA with hyperthyroidism. A 28-year-old previously healthy woman presented with gradual-onset abdominal swelling, exertional dyspnea, and diarrhea. Hyperthyroidism and heart failure were diagnosed using laboratory investigation and echocardiography. Ultrasonography revealed a large amount of ascites. The ascitic fluid was milky with elevated triglyceride levels. Treatment with anti-thyroid therapy and diuretics improved all symptoms, and the free triiodothyronine (T3) level normalized after five days. Hyperthyroidism and heart failure should be considered as reversible causes of CA.  相似文献   
37.
Background  Risk factors of surgical site infection (SSI) after hepatectomy under the guideline of Centers for Disease Control and Prevention (CDC) are not well examined. Methods  Hospital records of consecutive patients who underwent hepatectomy without biliary reconstruction for liver cancers were reviewed retrospectively. Prophylactic antibiotics were given to patients just before skin incision and every 3 hours during the operations. Clinicopathological factors were compared between patients who developed SSI and those without it. Results  There were 405 patients identified, and the incidence of SSI was 23 cases (5.8%). In multivariate analysis, intraoperative bowel injury, blood loss >2000 ml, and age older than 65 years were significant risk factors of SSI after hepatectomy. Conclusions  Prophylactic antibiotics were necessary only during the operation for most patients who underwent hepatectomy without biliary reconstruction. However, patients with intraoperative bowel injury, blood loss >2000 ml, and age older than 65 years are at risk to develop SSI and might need additional administration of prophylactic antibiotics after surgery.  相似文献   
38.
39.
We recently reported that osteopontin (OPN) and calprotectin (CPT) are present in the matrix of urinary calcium stones, and that OPN mRNA is expressed in the renal distal tubular cells. In the present study, we examined the immunohistochemical distributions of OPN and CPT in urinary stones. The stones used in this study were passed spontaneously from the upper urinary tract. One half of each of the stones was analyzed with an infrared spectrophotometer, and were shown to be comprised of calcium oxalate, calcium phosphate, uric acid and cystine. The other half of each stone was immersed in tetrasodium ethylenediamine-tetraacetate (EDTA) solution. The half-stones were embedded in paraffin and cut into 5-μm sections. The avidin-biotin-peroxidase complex technique was employed. A monoclonal antibody to human milk-derived OPN and a monoclonal antibody to human granulocyte-derived CPT were used as primary antibodies. The immunochemical study using the OPN and CPT antibodies showed positive staining of the matrix of the urinary calcium stones. The stones showed staining in two distinct zones: a core area was stained with randomly aggregated OPN and CPT, and peripheral layers were stained in concentric circles. On the basis of our observations, it is reasonable to presume that OPN and CPT play roles as the matrix in the structure of urinary calcium stones. Received: 24 February 1998 / Accepted: 28 January 1999  相似文献   
40.
Purpose: To evaluate the effects of bare stents and covered stents on the aortic wall, especially the vasa vasorum. Methods: Eight bare stents and nine covered stents were placed in the infrarenal aorta of nine dogs. The dogs were euthanized at 4–45 weeks after stent placement. The vasa vasorum was evaluated by microstereoscopy with vascular casting, and the histopathology of the aortic wall was examined by light microscopy. Results: In the unstented normal aorta, vasa vasorum nourished the adventitia and the outer media, and the intima and inner media were avascular. In the stented segment, vascular dilatation and proliferation of vasa vasorum, medial atrophy, and intimal hyperplasia were observed, more prominent for covered stents than for bare stents. Conclusion: Intravascular stent placement caused not only medial atrophy and intimal hyperplasia but also proliferation of the vasa vasorum, probably due to hypoxia in the aortic wall. Received: 0/00/00/Accepted: 0/00/00  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