首页 | 官方网站   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   5018篇
  免费   281篇
  国内免费   23篇
医药卫生   5322篇
  2022年   34篇
  2021年   53篇
  2020年   39篇
  2019年   36篇
  2018年   52篇
  2017年   53篇
  2016年   67篇
  2015年   75篇
  2014年   86篇
  2013年   86篇
  2012年   171篇
  2011年   248篇
  2010年   139篇
  2009年   158篇
  2008年   220篇
  2007年   224篇
  2006年   276篇
  2005年   265篇
  2004年   261篇
  2003年   235篇
  2002年   268篇
  2001年   231篇
  2000年   223篇
  1999年   172篇
  1998年   65篇
  1997年   50篇
  1996年   49篇
  1995年   41篇
  1994年   28篇
  1993年   29篇
  1992年   91篇
  1991年   99篇
  1990年   72篇
  1989年   97篇
  1988年   97篇
  1987年   97篇
  1986年   98篇
  1985年   78篇
  1984年   46篇
  1983年   64篇
  1982年   35篇
  1980年   36篇
  1979年   58篇
  1978年   34篇
  1973年   32篇
  1970年   26篇
  1969年   29篇
  1968年   36篇
  1967年   31篇
  1966年   30篇
排序方式: 共有5322条查询结果,搜索用时 0 毫秒
1.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
2.
We examined radiographs of the elbows of the pitching arms of 79 professional baseball pitchers (mean age, 25.1 years; mean duration of professional career, 4.7 years) and noted the frequency and size of spurs, bone fragments, and intra-articular loose bodies according to site. The influence of duration of professional baseball career on these osteoarthritic changes was also investigated. The olecranon tip was the most frequent site of spurs (62/79; 78.5%), and fragmentation of the spur was detected in 17 joints. The frequency of spurs was also high at the medial margin of the olecranon, the tip of the coronoid process, the medial margin of the sigmoid notch, the medial margin of the trochlea and the olecranon fossa. In 38 subjects, spurs were observed at the distal portion of the radial notch of the ulna. However, few pitchers had osteoarthritic changes in the humeral capitellum or radial head. Intra-articular loose bodies were detected in 4 of 79 joints (5.1%), and bone fragments were present below the medial humeral epicondyle in 25 of 79 joints (31.6%). Osteoarthritic changes in the elbow joint appeared to be attributable mainly to traction stress and impingement associated with extension and valgus strain. Significant osteoarthritic changes were often found in professional pitchers whose careers exceeded 5 years.  相似文献   
3.
The biosynthesis of biotin-vitamers from various carbon sources by the members of the Enterobacteriaceae as one of the groups of intestinal bacteria was investigated. The biotin-vitamers synthesized in each case included one or more of dethiobiotin (main product), 7-keto-8-aminopelargonic acid, and biotin. True biotin was shown to be synthesized under aerobic conditions but not under anaerobic conditions by each of several strains belonging to one of the genera, Erwinia, Escherichia, Proteus, and Serratia, and using culture media containing one of galactose, peptone, Polypepton, or casamino acid. In addition, a biotin precursor, pimelic acid, was also synthesized by several bacteria utilizing carbon sources such as maltose, mannose, galactose, peptone, or casamino acid.  相似文献   
4.
5.
A 75‐year‐old male was admitted to the gastroenterology unit of Nagoya City University Hospital due to epigastralgia after surgical treatment for right renal cancer. Endoscopy revealed advanced type 1 gastric cancer in the corpus of the stomach and multiple polypoid lesions in the stomach and duodenum. X‐ray examination of the small intestine using barium showed multiple polyps in the upper jejunum. Faint pigmentation on the palm was also detected. Peutz‐Jeghers syndrome (PJS) was diagnosed, despite a lack of family history. Total gastrectomy, resection of part of the upper jejunum and intraoperative endoscopic polypectomy of duodenal polyps was performed. This is the second reported case of PJS associated with renal cancer. We also detected a missense mutation in the tumor suppressor gene STK11 that, when mutated, is causative for PJS.  相似文献   
6.
7.
LD78 is a cDNA newly isolated from human stimulated tonsillar lymphocytes. The expression of LD78 is related to inflammatory responses and its structure has a homology with macrophage inflammatory protein 1-alpha, which is known to have an inhibitory effect on murine CFU-S. Using a colony assay technique, we examined the effects of LD78 on human hemopoietic progenitors. The addition of doses of 100 ng/ml or more of LD78 suppressed the colony formation of KMT-2, a factor-dependent myelomonocytic cell line established from cord blood cells; this suppressive activity was neutralized by the addition of antibody against LD78. The same doses of LD78 suppressed the formation of neutrophil, macrophage, and megakaryocytic colonies which were supported by human interleukin-3 and erythropoietin; however, LD78 did not affect colony formation by either non-phagocytic mononuclear cells or sorted CD34+ cells. The conditioned medium of KMT-2 cells or peripheral blood mononuclear cells cultured with LD78 suppressed colony formation by CD34+ cells. From these findings, it is suggested that LD78 affects phagocytic cells and induces factors that are inhibitory for hemopoiesis. We consider LD78 to be a new cytokine that plays an inhibitory role in hemopoiesis.  相似文献   
8.
A 74-year-old female with hereditary xanthinuria and xanthine stones is reported. She has a family history of consanguineous parents and a past history of right side nephrectomy due to a xanthine renal stone and vesicolithotomy of 3 bladder stones approximately 5 X 4 X 4 cm in size at the age of 58 and 71, respectively. Her young brother exhibited a slightly elevated urinary excretion of oxypurines. Laboratory examination showed a low serum level (0.3 mg/dl) and urinary excretion (1.56 mg/day) of uric acid, and high plasma and urine levels of oxypurines. No xanthine oxidase activity was detectably in duodenal mucosa by biopsy specimen obtained by duodenofiberscopy. Now she has another stone approximately 5 X 4 X 4 cm in her bladder. There have been are few elderly cases of hereditary xanthinuria with recurrent giant urolithiasis.  相似文献   
9.
1. Effects of potassium (K) supplementation (100 mEq/day) on urinary sodium (Na) excretion and on the secretion of atrial natriuretic polypeptide (ANP) during salt loading (350 mEq/day) were studied in 12 healthy salt-resistant normotensives under strictly controlled metabolic ward conditions. 2. Urinary volume and Na excretion on the first day of the high salt period (HSP) were significantly greater in the K-supplemented group (KG) than in the control group (CG). 3. There was a significant gain in bodyweight after salt loading in both groups, with a significantly greater gain in CG on the second day of HSP. Haematocrit decreased significantly during salt loading in both groups, the degree of which was significantly greater in CG. 4. Plasma norepinephrine decreased significantly during salt loading in both groups, the degree of which was significantly less in KG than in CG. A significant increase in plasma ANP was observed in CG on and after the second day of HSP, while a significant increase in plasma ANP was observed on the fifth day of HSP in KG. 5. These findings indicate that K supplementation accelerates diuresis and natriuresis, resulting in moderate suppression of volume expansion induced by salt loading and that this accelerated diuresis and natriuresis is not a result of the action of ANP.  相似文献   
10.
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-23

京公网安备 11010802026262号