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   1434009篇
  免费   97008篇
  国内免费   3130篇
耳鼻咽喉   19618篇
儿科学   45521篇
妇产科学   39291篇
基础医学   212922篇
口腔科学   39662篇
临床医学   123118篇
内科学   280675篇
皮肤病学   31090篇
神经病学   112340篇
特种医学   56020篇
外国民族医学   398篇
外科学   220824篇
综合类   27564篇
一般理论   425篇
预防医学   106142篇
眼科学   32447篇
药学   105169篇
中国医学   2748篇
肿瘤学   78173篇
  2018年   15298篇
  2017年   11711篇
  2016年   13035篇
  2015年   14645篇
  2014年   20398篇
  2013年   31065篇
  2012年   42349篇
  2011年   45240篇
  2010年   27088篇
  2009年   25514篇
  2008年   42902篇
  2007年   45930篇
  2006年   45906篇
  2005年   44843篇
  2004年   43073篇
  2003年   41219篇
  2002年   40683篇
  2001年   63064篇
  2000年   65017篇
  1999年   54899篇
  1998年   15680篇
  1997年   14017篇
  1996年   14060篇
  1995年   13084篇
  1994年   12389篇
  1993年   11653篇
  1992年   42576篇
  1991年   41900篇
  1990年   41394篇
  1989年   39960篇
  1988年   36980篇
  1987年   36437篇
  1986年   34828篇
  1985年   33260篇
  1984年   24832篇
  1983年   21224篇
  1982年   12518篇
  1979年   23316篇
  1978年   16590篇
  1977年   14071篇
  1976年   13371篇
  1975年   14956篇
  1974年   17801篇
  1973年   16878篇
  1972年   16188篇
  1971年   15180篇
  1970年   14407篇
  1969年   13628篇
  1968年   12908篇
  1967年   11795篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
931.
Rats were chronically exposed to poisonous sodium selenite in concentrations 0.5 mg/kg b. m. for 10 weeks. As a result, hydroxyproline contents in blood serum increased, as well as its excretion with urine. It was proved that the procedure enhanced urinary glycosaminoglycane excretion and increased the contents of the protein-related glycosaminoglycanes in the serum. This was accompanied by increased quantities of keratane sulphate and heparin sulphate. The results confirmed that selenium poisonings influenced connective tissues.  相似文献   
932.
933.
Preoperative screening for potential cardiac complications is crucial in making rational decisions about surgery. A number of classification schemes are available to aid the primary care physician in assessing a patient's perioperative cardiac risk. In general, these schemes enable the physician to place patients in low-risk, moderate-risk and high-risk categories. Patients at low risk can often be safely referred for surgery with minimal preoperative evaluation, while those at potentially high risk frequently need further assessment and medical or surgical treatment of cardiac disease prior to surgery. The classification schemes are most accurate in identifying patients at high risk for perioperative cardiac complications. However, patients with silent underlying cardiac disease are often underclassified with respect to potential risk. For those patients, accurate prediction of perioperative cardiac complications can be challenging.  相似文献   
934.
Single or combined monoclonal antibodies (McAbs) Zh53, Zh820, and Zh2-1 have been used to eliminate malignant clonogenic cells from human bone marrow. The test of cytotoxicity showed that all of these McAbs could express high specific cytotoxic action against HL-60 cells and were selectively complement-dependent cytotoxic to various types of fresh leukemic cells. Clonogenic assay detected that single treatment with antibody and rabbit complement (RC) could reduce clonogenic units of HL-60 cells by more than 2 logs and two treatments reduced clonogenic units by more than 4 logs. However, combination of 2 McAbs could reduce clonogenic units by 4-5 logs. The data suggest that multiple treatments with McAbs and RC or a combination of 2 McAbs are more effective than a single treatment in eliminating clonogenic tumor cells. Treatment of normal human bone marrow with Zh53, Zh2-1 and RC did not produce a loss of normal CFU-GM, but treatment with Zh820 reduced the clonic units of normal CFU-GM by 24%.
  相似文献   
935.
936.
The cellular infiltrate present in human diseased gingiva was analyzed in biopsies from 12 patients with gingivitis or periodontitis. The samples studied had been obtained in the course of surgery at inflammatory sites remaining after institution of periodontal treatment. Histological and immunological techniques were used to identify macrophages, B-cells, plasma-cells, T-cells and T cell subsets, as well as cells expressing class II HLA membrane antigens. T-cells appeared as the predominant population, but plasma-cells were also visualized in nearly all samples. Both OKT4+ and OKT8+ cells were seen in all cases, the latter being more numerous in periodontitis patients. Interdigitating-like cells were observed, positively labelled for class II antigens, as well as macrophages which were more numerous in periodontitis patients. These results suggest the participation of all components of the immune response in gingival disease, in a way resembling chronic recurrent inflammatory diseases.  相似文献   
937.
Obese Zucker rats are less responsive than their lean littermates to the effects of cholecystokinin-octapeptide on satiety and pancreatic growth and exocrine function. We hypothesized that the hyperphagia observed in obese Zucker rats may be caused by a decreased pyloric contractile response to cholecystokinin, resulting in an increased rate of gastric emptying, decreased postprandial gastric distention, and thus decreased satiety. Pyloric muscle strips from six obese Zucker rats and six lean littermates were mounted in separate tissue baths and isometric contraction was measured in response to acetylcholine and cholecystokinin-octapeptide. The dose-response curves for acetylcholine-and cholecystokinin-octapeptide-stimulated pyloric muscle contraction were similar for both the obese and the lean rats. (For cholecystokinin, D50 obese=4.0±0.6 nM, D50 lean=3.4±0.2 nM;P=0.16). We conclude that the decreased satiety response to cholecystokinin-octapeptide observed in obese Zucker rats is not secondary to a decreased pyloric responsiveness to cholecystokinin.This work was supported by NIH grant AM28303-03.  相似文献   
938.
Radionuclide brain scintigraphy and computed tomography (CT) demonstrated cerebral lesions in two patients with acquired immunodeficiency disease syndrome (AIDS) complicated by opportunistic infection of the brain. In the detection of these cerebral lesions, [99mTc]DTPA radionuclide scintigraphy was as reliable as CT. Since malignant lymphoma involving the brain has been seen with increasing frequency in patients with AIDS, the positive brain scan alone is nonspecific and should be correlated appropriately with the clinical setting.  相似文献   
939.
Partial splenectomy in Gaucher's disease   总被引:2,自引:0,他引:2  
In 11 children with hypersplenism due to Gaucher's disease, partial splenectomy was planned with the aim to prevent the development of postsplenectomy sepsis and also to slow the advance of the disease in the rest of the reticuloendothelial system by permitting continuing accumulation of the beta-glucocerebroside in the remaining splenic tissue. In seven children, partial splenectomy was performed successfully, the weight of the splenic tissue removed ranging from 400 to 3,680 g. The postoperative course was uneventful and the average duration of hospitalization was 12 days. In subsequent follow-up, isotope scanning demonstrated continuing growth of the splenic remnant and there were no episodes of postsplenectomy sepsis nor evidence of increased accumulation of beta-glucocerebroside in the liver or bones. These children showed a marked improvement in the growth curve and dramatic improvement in the hematologic picture. Of the four remaining children, in two, partial splenectomy was followed by complete removal of the remaining spleen due to necrosis, whereas in two, total splenectomy was performed since the huge spleens were extensively infarcted. Our experience suggests that partial splenectomy is the treatment of choice in the management of young patients with hypersplenism due to Gaucher's disease.  相似文献   
940.
Four cases of high-flow carotid-cavernous sinus fistula (CCF), three of them posttraumatic and one spontaneous, have been treated by a direct surgical approach to the cavernous sinus. The CCF's were obliterated by the introduction into the cavernous sinus of muscle fragments and/or fibrin sealant. In the three cases with a preoperatively patent internal carotid artery (ICA), the CCF was occluded and the ICA flow preserved. One of these also had a posttraumatic false aneurysm that enclosed the two avulsed ends of a transected intracavernous ICA. This was treated by cervical ICA ligation following resolution of the CCF. A fourth patient, who had previously undergone an unsuccessful ICA trapping procedure elsewhere, also obtained a good result. The case histories and the surgical technique are presented. Direct intracavernous obliteration with muscle fragments and fibrin sealant fulfills the criteria for treatment of high-flow CCF's: occlusion of the arteriovenous fistula and preservation of the ICA circulation. While this surgical technique is a therapeutic option in some cases, it appears to have precise indications in others.  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