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   3430432篇
  免费   241339篇
  国内免费   9375篇
耳鼻咽喉   48379篇
儿科学   111459篇
妇产科学   97265篇
基础医学   481771篇
口腔科学   97186篇
临床医学   308492篇
内科学   669743篇
皮肤病学   81693篇
神经病学   279967篇
特种医学   132671篇
外国民族医学   1122篇
外科学   516416篇
综合类   72786篇
现状与发展   11篇
一般理论   1301篇
预防医学   256868篇
眼科学   79096篇
药学   252471篇
  12篇
中国医学   7126篇
肿瘤学   185311篇
  2018年   35987篇
  2017年   27945篇
  2016年   32156篇
  2015年   36208篇
  2014年   50075篇
  2013年   75581篇
  2012年   99754篇
  2011年   105654篇
  2010年   63744篇
  2009年   61120篇
  2008年   99334篇
  2007年   106304篇
  2006年   107854篇
  2005年   103741篇
  2004年   100199篇
  2003年   97059篇
  2002年   93951篇
  2001年   160873篇
  2000年   164940篇
  1999年   139514篇
  1998年   40151篇
  1997年   35817篇
  1996年   35460篇
  1995年   34215篇
  1994年   31556篇
  1993年   29592篇
  1992年   109073篇
  1991年   105318篇
  1990年   102331篇
  1989年   99257篇
  1988年   91553篇
  1987年   89806篇
  1986年   84829篇
  1985年   81075篇
  1984年   60764篇
  1983年   51624篇
  1982年   30927篇
  1981年   27709篇
  1979年   55252篇
  1978年   39255篇
  1977年   33841篇
  1976年   31034篇
  1975年   34024篇
  1974年   40105篇
  1973年   38498篇
  1972年   36376篇
  1971年   33948篇
  1970年   31661篇
  1969年   30542篇
  1968年   28342篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Based on a standardized in-vitro method for quantifying the activity of prostaglandin-synthetase by means of coupling malondialdehyde with 2-thiobarbituric acid the possibility of using this method also as ex-vivo technique is described. By this, more favourable prerequisites to pharmacological valuation of the effects of potential antiinflammatory substances exists compared to the application of in-vitro results, only.  相似文献   
992.
993.
994.
After admission to hospital for bed rest, 200 women with multiple pregnancies were randomly allocated to receive either 4 mg of salbutamol orally five times daily, or to receive no drug. After an average of 6 weeks treatment, no difference between the experimental groups could be detected with respect to duration of gestation, birthweight or any other of the outcomes of pregnancy observed.  相似文献   
995.
996.
997.
Patients with Fabry disease on dialysis in the United States.   总被引:9,自引:0,他引:9  
BACKGROUND.: Fabry disease results from an X-linked deficiency of lysosomal alpha-galactosidase A and is a rare cause of end-stage renal disease. Little is known about the characteristics of patients with Fabry disease that initiate dialysis in the United States, although data from Europe suggests these individuals have a poor survival. METHODS.: Using the United States Renal Disease System database, we first studied in detail 42 Fabry patients who initiated dialysis between April 1995 (following the introduction of the new detailed HCFA 2728 form) and July 1998. To examine crude survival in a larger cohort, 95 Fabry patients were studied who initiated dialysis between 1985 and 1993, similar to the European Registry. Diabetic and non-diabetic controls matched by age, gender, race, year of dialysis initiation, and initial dialysis modality were examined for comparison. RESULTS.: During the years 1995 to 1998, the mean age of Fabry patients that initiated dialysis was 42 years, 83% were Caucasian, and 10% were African American. Despite the X-linked inheritance of Fabry disease, 12% of Fabry patients on dialysis were female. At initiation of dialysis mean serum albumin and creatinine were significantly higher and mean body mass index was significantly lower among Fabry patients, but mean glomerular filtration rate was similar to controls. Fabry patients tended to have a lower three-year survival compared to non-diabetic controls, but the results were not significantly different. In a larger cohort of Fabry patients who initiated dialysis between 1985 and 1993, the three-year survival of Fabry patients was significantly lower than non-diabetic controls: 63% (95% CI, 50 to 75%) versus 74% (95% CI, 67 to 80%; P=0.03). CONCLUSION.: End-stage renal disease is associated with significant morbidity and mortality among patients with Fabry disease. Recent evidence that progression of Fabry disease may be attenuated by enzyme replacement therapy necessitates increased awareness of Fabry disease and its comorbidities.  相似文献   
998.
Acoustic analysis of a reading passage was used to identify the abnormal phonatory events associated with adductor spasmodic dysphonia (ADSD) pre- and postinjection of Botulinum Toxin A (Botox). Thirty-one patients (age 22 to 74 years) diagnosed with ADSD were included for study. All patients were new recipients of Botox, and the examination of their voice occurred before and after their initial injection of Botox. Acoustic events were identified from reading samples of the Rainbow Passage produced by each of the patients. These events were examined from sentences containing primarily voiced sound segments. Dependent variables included the number of phonatory breaks, frequency shifts, and aperiodic segments--all variables previously defined by the investigators. Additionally, calculated variables were made of the percentage of time these events occurred relative to the duration of the cumulative voiced segments. A sex- and age-matched control group (+/-2 years) was included for statistical comparison. Results indicated that those with ADSD produced more aberrant acoustic events than the controls. Aperiodicity was the predominant acoustic event produced during the reading, followed by frequency shifts and phonatory breaks. Within the ADSD group, the number of atypical acoustic events decreased following Botox injection. It is important that the occurrence of specific abnormal acoustic events was sufficient to differentiate the disordered speakers from the controls following as well as preceding initial Botox injection, as indicated by discriminant function analysis. This paper complements our previous work using this acoustic analysis method for defining the abnormal events present in the voice of those with ADSD and further suggests that these measures can be used in conjunction with perceptual impressions to differentiate speakers on the basis of initial severity.  相似文献   
999.
Microepidermabrasion has become a common modality in aesthetic skin care in doctor's offices as well as in the hands of skin care specialists. The basics of particle beam resurfacing are discussed, with an emphasis on patient selection, technique, and after care. Concerns about current technology are reviewed, and insight into the evolution of new technologies is given.  相似文献   
1000.
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