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   104832篇
  免费   8743篇
  国内免费   6143篇
耳鼻咽喉   1113篇
儿科学   1546篇
妇产科学   2304篇
基础医学   12424篇
口腔科学   1957篇
临床医学   14027篇
内科学   16591篇
皮肤病学   896篇
神经病学   5677篇
特种医学   3533篇
外国民族医学   42篇
外科学   11256篇
综合类   14853篇
现状与发展   23篇
一般理论   20篇
预防医学   6134篇
眼科学   2865篇
药学   10723篇
  56篇
中国医学   4862篇
肿瘤学   8816篇
  2024年   280篇
  2023年   1505篇
  2022年   3810篇
  2021年   4984篇
  2020年   3525篇
  2019年   3236篇
  2018年   3548篇
  2017年   2933篇
  2016年   2849篇
  2015年   4419篇
  2014年   5627篇
  2013年   5019篇
  2012年   7542篇
  2011年   8286篇
  2010年   4987篇
  2009年   3835篇
  2008年   5294篇
  2007年   5545篇
  2006年   5414篇
  2005年   5712篇
  2004年   3830篇
  2003年   3399篇
  2002年   3006篇
  2001年   2440篇
  2000年   2653篇
  1999年   2703篇
  1998年   1578篇
  1997年   1481篇
  1996年   1308篇
  1995年   1161篇
  1994年   982篇
  1993年   635篇
  1992年   998篇
  1991年   806篇
  1990年   684篇
  1989年   600篇
  1988年   593篇
  1987年   529篇
  1986年   420篇
  1985年   330篇
  1984年   208篇
  1983年   159篇
  1982年   85篇
  1981年   98篇
  1980年   83篇
  1979年   115篇
  1978年   54篇
  1977年   56篇
  1975年   44篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
目的了解初级护士资格考试通过情况。方法采用历史性研究方法,对我校近3年参加护士资格考试的188名学生考试情况进行调查。结果护士资格考试通过率低,其中基础知识通过率在4个科目中最低。结论有必要对参加考试的考生进一步强化基础知识的训练,从而提高护士资格考试的过线率。  相似文献   
92.
93.
The effect of p.o. administration of tea on nitrosamine-induced carcinogenesis was investigated. Female A/J mice were given N-nitrosodiethylamine (NDEA) (10 mg/kg) p.o. once a week for 8 weeks and were killed 16 weeks after the last dose. More than 90% of the mice had forestomach and lung tumors. The animals had an average of 8.3 forestomach and 2.5 lung tumors/mouse. With 0.63 or 1.25% green tea infusion (12.5 g green tea leaves brewed with 1 liter of boiling water) as the sole source of drinking water for the entire experimental period, the pulmonary tumor incidence was decreased by 18 or 44%, and the tumor multiplicity was reduced by 36 or 60%, respectively. The treatments also decreased the forestomach tumor incidence by 18 or 26% and tumor multiplicity by 59 or 63%, respectively. Administration of 0.63 or 1.25% green tea infusion, either during the NDEA treatment period only or starting 1 week after the completion of NDEA treatment, also decreased the pulmonary tumor incidence and multiplicity and the forestomach tumor multiplicity. The inhibitory effects of green tea infusion were also observed in a similar experiment using a higher dosage of NDEA (20 mg/kg). Treatment of female A/J mice with a single dose (103 mg/kg) of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) resulted in the formation of pulmonary adenomas in almost all of the animals with an average of 9.3 tumors/mouse after 16 weeks. When 0.6% decaffeinated green tea or black tea extract was given during the NNK-treatment period, tumor multiplicity was reduced by 67 or 65%, respectively. When the tea extract was given after the NNK-treatment period until the end of the experiment, 0.6% green tea extract decreased the tumor incidence and multiplicity by 30 and 85%, respectively. In this protocol, 0.6% black tea extract reduced tumor multiplicity by about 63% but did not significantly affect the tumor incidence. The results clearly demonstrated an inhibitory action of green tea and black tea on nitrosamine-induced tumorigenesis.  相似文献   
94.
明党参鲜根与药材饮片中精油成分和氨基酸含量比较   总被引:4,自引:1,他引:3  
对明党参鲜根和饮片中的精油及氨基酸成分进行了比较分析,鉴定出27种精油成分,并发现炮制前后氨基酸成分含量变化较大。  相似文献   
95.
T lymphocytes play a fundamental role in the initiation and regulation of chronic inflammatory responses in patients with asthma. CD69 is an early marker of T‐cell activation. The levels of intercellular adhesion molecule‐1 (ICAM‐1, CD54) and L ‐selectin have been reported to increase in patients with allergic diseases and asthma. The present study was therefore undertaken to investigate the expression of CD69, CD54, and L ‐selectin by T lymphocytes of children with asthma, before and after immunotherapy. Eighteen children newly diagnosed with asthma, 11 good and nine poor responders to immunotherapy, and 16 normal subjects, were enrolled in this study. The percentages of CD69+, CD54+, and CD62L+ cells in T lymphocytes were measured by using flow cytometry. The levels of CD69, CD54, and CD62L in serum and culture supernatants were determined by using enzyme‐linked immunosorbent assay (ELISA). The expression of CD69 and CD54 on CD3+ T lymphocytes was significantly higher in children with asthma than in control patients. All the patient groups expressed (spontaneously and following stimulation with phorbol myristate acetate and ionomycin together with mite‐extract proteins) greater amounts of CD69 and CD54 than did control subjects. With long‐term immunotherapy, the percentages of CD69+ and CD54+ T lymphocytes were significantly lower in patients with a good response to immunotherapy. Our results also showed significantly lower serum L ‐selectin levels following immunotherapy. In conclusion, successful immunotherapy resulted in decreased expression and production of CD69 and CD54. These results may explain, in part, the clinical efficacy of immunotherapy.  相似文献   
96.
网络模式下临床医师绩效评价指标体系研究   总被引:2,自引:0,他引:2  
为了充分利用医院信息网络信息,更为全面、客观地对医生进行评价,阐述建立网络模式下临床医师绩效评价指标体系的原则、方法,并对的建立指标体系的可信度及合理性进行了分析。  相似文献   
97.
The effects of an externally applied direct-current electric field on the movement of cultured rabbit corneal epithelial cells and stromal fibroblasts were studied. After a latency of approximately 20 minutes in an electric field, both epithelial cells and stromal fibroblasts became spindle shaped and underwent galvanotropism by aligning their long axes perpendicular to the applied electric field. The electric field stimulus thresholds for galvanotropic movements in epithelial cells and stromal fibroblasts were 4V/cm and 6 V/cm, respectively. After an additional latency of 30 minutes, both cell types manifested galvanotaxic movements: epithelial cells commenced migration in the cathodal (downfield) direction and stromal fibroblasts in the anodal (upfield) direction. For both types of cells, ruffled membranes and lamellipodia were abundant at the leading edges of migrating cells and cell processes underwent retraction at the trailing edges. At field strengths of above 10 V/cm, evidence of cellular damage (manifested by cellular rounding and detachment), attributable to the electric field treatment, was observed after 4 hours. These preliminary results suggest that galvanotaxic responses could be exploited clinically in the enhancement of corneal wound healing.  相似文献   
98.
99.
小切口胆囊切除术108例临床观察   总被引:1,自引:0,他引:1  
本文报告腹部切口5-8cm的小切口胆囊切除术108例,与同期大切口胆囊切除术相比,具有创伤较小、恢复较快、并发症少、切口疤痕小的优点,虽不如腹腔镜胆囊切除术(LC)的疼痛轻、恢复快,但并症比LC少,只要适应症选择得当,在术者的经验和技术较成熟的情况下,不昔为一种可供选择的方法。  相似文献   
100.
采用连续流动反应装置,考察了裂解汽油在HZSM-5与金属元素改性的HZSM-5上的芳构化反应,发现锌改性后提高了液体产物中芳烃的收率。为了克服裂解汽油中含硫含焦杂质的影响,提出了获取芳烃的有效工艺:蒸馏除焦-加氢预脱硫-氢气氛下芳构化反应-冷凝产物。用氨吸附的程序升温脱附法,将催化剂的酸性质与其催化芳构化作用进行关联,认为Zn改性后的HZSM-5催化剂具有较温和的酸中心,可能是其芳构化高活性与高选择性的原因。  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