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   10042篇
  免费   605篇
  国内免费   14篇
耳鼻咽喉   86篇
儿科学   340篇
妇产科学   219篇
基础医学   1265篇
口腔科学   120篇
临床医学   1205篇
内科学   1918篇
皮肤病学   218篇
神经病学   1072篇
特种医学   386篇
外科学   1104篇
综合类   61篇
一般理论   5篇
预防医学   1020篇
眼科学   286篇
药学   551篇
中国医学   13篇
肿瘤学   792篇
  2023年   73篇
  2022年   133篇
  2021年   226篇
  2020年   187篇
  2019年   250篇
  2018年   306篇
  2017年   253篇
  2016年   224篇
  2015年   254篇
  2014年   332篇
  2013年   492篇
  2012年   756篇
  2011年   762篇
  2010年   388篇
  2009年   384篇
  2008年   633篇
  2007年   585篇
  2006年   592篇
  2005年   536篇
  2004年   476篇
  2003年   451篇
  2002年   427篇
  2001年   147篇
  2000年   123篇
  1999年   118篇
  1998年   105篇
  1997年   91篇
  1996年   62篇
  1995年   38篇
  1994年   45篇
  1993年   48篇
  1992年   61篇
  1991年   71篇
  1990年   65篇
  1989年   70篇
  1988年   48篇
  1987年   48篇
  1986年   61篇
  1985年   49篇
  1984年   40篇
  1983年   29篇
  1982年   36篇
  1976年   25篇
  1975年   27篇
  1973年   37篇
  1972年   29篇
  1971年   27篇
  1970年   32篇
  1968年   26篇
  1967年   26篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
1.
According to the current nutritional recommendations issued by professional diabetes and nutrition associations, diabetic patients should keep to a diet consisting of 45–60% carbohydrates, 10–20% protein, and not more than 35% fat. However, not all of these nutritional recommendations are evidence based. For example, current studies show that the intake of insoluble roughage may be underrepresented. It is also possible that diabetic patients could benefit from keeping to the lower end of the recommended range for carbohydrates (45%) and the upper end of the range advised for protein (20%).  相似文献   
2.
Cytokines as therapeutic drugs.   总被引:1,自引:0,他引:1  
Cytokines are a growing group of proteins that are responsible for the communication of cells of the immune system, hematopoietic cells, and other cell types. They play a dominant role in various diseases, particularly in promoting and perpetuating inflammation. Cytokine production is a reaction of the body to a pathologic state to restore homeostasis. In such cases, the therapeutic intervention should support the reaction of the body by giving the cytokine itself (agonistic therapeutics). In other cases, manifestation of a disease results from an overproduction of cytokines, making cytokine antagonists desirable therapeutic drugs. Furthermore, cytokines may be good candidates as cancer therapeutics, especially to support the restoration of blood cell populations after chemotherapy or radiation.  相似文献   
3.
BACKGROUND: Gastric cancer (GC) is the leading cause of cancer deaths in China. Our study prospectively evaluated the impact of repeated endoscopic screens on GC mortality in a high-risk population in China. METHODS: Between 1989 and 1999, a population-based gastroscopic screening was conducted in 4,394 residents of Linqu County, China, a region with the highest rates of GC worldwide. Residents ages 35 to 64 years received initial gastroscopies with biopsies in 1989. Repeated endoscopies were performed in 1994 and 1999. Cancer occurrences and deaths were actively monitored throughout the entire period until July 2000. Mortality from GC was compared with expected values based on mortality rates obtained for Linqu in the 1990-1992 Chinese Cancer Mortality Survey. RESULTS: Between March 1989 and July 2000, 39,303 person-years were accumulated; 85 new GCs occurred, 29 (34.5%) were in early stage. Fifty-eight cases (68%) were identified at one of the screens. The number of observed deaths from GC (37) was close to the expected (36.8). The standardized mortality ratio was 1.01 (95% CI 0.72-1.37) for the entire cohort, 1.13 (95% CI 0.77-1.57) for males, and 0.65 (95% CI 0.26-1.32) for females. CONCLUSIONS: Despite high population coverage with repeated screens, no reduction in GC mortality was observed in this high-risk population in China.  相似文献   
4.
The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.  相似文献   
5.
INTRODUCTION: Incisor trauma is a significant clinical problem in children and adolescents. The purposes of this study were to report on the prevalence and severity of incisor trauma in a large population-based sample of adolescent Kuwaiti residents in the early permanent dentition, to determine the ages of and reasons for the injuries, and to test for any effects of sex, incisor occlusion, and lip coverage on the prevalence of incisor trauma. METHODS: Presence and type of traumatic injury were scored according to the National Institute of Dental Research index in a population-based sample of 795 girls and 788 boys with a mean age of 13.24 years (SD 0.42). RESULTS: Trauma prevalence was higher (P < .001) in boys (19.3%) than in girls (9.7%), and in the maxilla (13.6%) than in the mandible (1.5%). Most (77.3 %) of the affected subjects had only 1 injured tooth, and most (83.7%) of the traumatized teeth were maxillary central incisors. A total of 90.3% of the injuries were unrepaired enamel or enamel/dentin fractures. The major reasons for the injuries were falls and blows indoors (48.4%) or outdoors (41.6%). Nearly two-thirds (63.0%) of the traumas occurred at age 10 years or later. Mean overjet (OJ) was larger (3.9 v 3.0 mm, P < .01), and lip incompetence more frequent (12.7% v 7.3%, P < .01) among the subjects with injured maxillary incisors than among those without. Logistic regression showed that the odds of maxillary incisor trauma were 2.8 times higher in subjects with OJ between 6.5 and 9.0 mm, and 3.7 times higher in subjects with OJ > or = 9.5 mm than in subjects with OJ < or = 3.5 mm. CONCLUSIONS: Multiple logistic regression showed that the risk of maxillary incisor trauma was about 2 times higher in boys than in girls, and that the risk increased by 13% for every millimeter of increase in OJ. Lip competence was not included in the model. No associations were found between occlusion and mandibular incisor trauma.  相似文献   
6.
The induction of a granulomatous inflammation by jellyfish toxins is rare. More typically, acute toxic and urticarial reactions are seen. An 11-year-old boy developed a striated urticarial erythema on the left cheek after contact with a gelatinous mass while swimming in the sea in Croatia. After initial erosion, a striated induration developed in the area of contact. Histological examination revealed a granulomatous inflammation with some eosinophils. While topical steroid-based antiinflammatory and antibacterial therapy over several weeks was not effective, topical therapy with tacrolimus 0.1% for two two-week treatment periods led to healing of the skin changes with a slight scar. There was no clinical recurrence after 5 month of follow-up.  相似文献   
7.
BACKGROUND: The purpose of this study was to access a sample of short-bowel patients receiving home total parenteral nutrition (HTPN) in their home environment and describe their HTPN experience using qualitative methodology. METHODS: Three semistructured, open-ended, in-depth interviews were conducted online over a 5-month period with 6 adults (aged 27 to 45 years) who received HTPN for 2 to 8 years, 3 children (aged 8 to 10 years) receiving HTPN since birth, and the children's mothers. The constant comparison method was used to code and categorize data, inductively develop themes, and create a taxonomy (flow chart) of themes from the data. Credibility of data analysis and themes was established by the prolonged engagement with subjects and subject review of themes identified. RESULTS: Six major themes emerged: affirmation of life, infusion-related complications, lifestyle adaptations, self-worth, isolation, and food intake. Within most themes, subjects described similar concerns and reactions. A clear difference occurred within the theme of food intake. Adults reported feeling constantly hungry and challenged with resisting temptation to eat restricted foods. They admitted to lack of consistency in following dietary restrictions and repeated attempts to consume contraindicated foods. Children expressed lack of desire for food and mothers complained of their children's refusal to eat. CONCLUSIONS: Using qualitative methods allowed insight into the HTPN experience and depiction of the daily challenges of being total parenteral nutrition-dependent from patients' and caregivers' perspectives. It provides insight into their reactions and behaviors. By gaining this type of awareness and understanding, clinical protocols and services can be planned that are more likely to derive successful outcomes.  相似文献   
8.
Summary A randomized prospective study was performed to compare the results of filtering surgery using a Limbusbased versus a Fornix-based conjunctival flap. The wound closure of the Fornix-based flap was performed using a running 10/0 nylon suture at the limbus. No statistical significant difference of IOP regulation was found between the two groups. There was a tendency of reduced occurrence of shallow anterior chamber and of less vascularized filtering blebs in the Fornix-based technique.  相似文献   
9.
10.
Thirteen patients with verified malignant mixed Müllerian tumor of the ovary treated in Denmark during the 7-year period 1981-87 were reviewed. Two patients had homologous and 11 patients had heterologous tumors. Four patients with early stage disease underwent radical surgery; 9 patients had stage III disease. Median survival for all 13 patients was 12 months. Six patients received platinum-containing cytotoxic therapy; 2 of these patients without measurable disease became long-term survivors (survival times 42+ and 92+ months, respectively) and 3 of the 4 remaining patients with evaluable disease obtained an objective remission.  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