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   9344篇
  免费   769篇
  国内免费   61篇
耳鼻咽喉   199篇
儿科学   304篇
妇产科学   160篇
基础医学   1132篇
口腔科学   188篇
临床医学   1240篇
内科学   1863篇
皮肤病学   94篇
神经病学   577篇
特种医学   372篇
外国民族医学   2篇
外科学   1247篇
综合类   236篇
一般理论   5篇
预防医学   1024篇
眼科学   282篇
药学   815篇
中国医学   9篇
肿瘤学   425篇
  2022年   67篇
  2021年   168篇
  2020年   102篇
  2019年   192篇
  2018年   169篇
  2017年   140篇
  2016年   158篇
  2015年   182篇
  2014年   256篇
  2013年   330篇
  2012年   472篇
  2011年   461篇
  2010年   323篇
  2009年   238篇
  2008年   361篇
  2007年   426篇
  2006年   386篇
  2005年   364篇
  2004年   309篇
  2003年   316篇
  2002年   295篇
  2001年   286篇
  2000年   298篇
  1999年   261篇
  1998年   136篇
  1997年   141篇
  1996年   129篇
  1995年   101篇
  1994年   103篇
  1993年   91篇
  1992年   217篇
  1991年   255篇
  1990年   191篇
  1989年   177篇
  1988年   153篇
  1987年   160篇
  1986年   160篇
  1985年   168篇
  1984年   114篇
  1983年   104篇
  1981年   68篇
  1980年   61篇
  1979年   101篇
  1978年   70篇
  1976年   73篇
  1974年   65篇
  1973年   68篇
  1972年   74篇
  1971年   62篇
  1970年   60篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
12.
13.
There is little agreement about the methodology of clinical trials of antipsychotic drugs in patients with negative symptoms. A literature review revealed wide variation in experimental design, rating scales and study duration. This reflects differing views as to the definition and response to treatment of negative symptoms. Some degree of standardization would improve comparability of studies and aid the development of new compounds. Patients included in such studies should have displayed negative symptoms for at least 6 months. Depressive symptoms, positive schizophrenic symptoms and extrapyramidal signs may all influence or be confused with negative symptoms and may respond to treatment; they should be at a low level at baseline and should be measured during the study period. Studies should last at least 8 weeks. Several scales are available for measuring negative symptoms and are reviewed; a global impression score should be used additionally.  相似文献   
14.
Ovariectomized (ovx) and parathyroidectomized (ptx) rat models of disturbed bone metabolism have been widely used in evaluating bone changes resulting from hormonal depletion, and are characterized by elevated and depressed bone turnover, respectively. We report here the expression of gelatinases extracted from native trabecular bone in these models. Nine-month-old female Sprague-Dawley rats were sacrificed after 3 weeks following ovx or 10 days post ptx to determine the influence of these procedures on the levels of proximal tibial bone tissue gelatinases. Identification and quantitation of these enzymes were performed via gelatin gel zymography of native tissue extracts and laser densitometry of developed gels, respectively. In the ptx model, a reduction in tissue levels of pro- and active-MMP-2 and 45 kDa activated fragment was seen, whereas ovx exhibited significant increases in these enzymes. The MMPs are therefore clearly under the influence of factors known to modulate bone remodeling in vivo. The study of MMP levels directly extracted from bone using these experimental models may assist in developing management regimes for metabolic bone diseases through the use of drugs aimed at controlling turnover.  相似文献   
15.
An adolescent with a history of attempted suicide who refused to involve his father in the treatment plan is presented. Issues surrounding consent to psychiatric treatment in childhood are discussed and the assessment process outlined. Contributions by primary healthcare professionals are emphasised.  相似文献   
16.
Sixty consecutive pregnant women with asymptomatic (covert) bacteriuria detected between 16 and 30 weeks gestation were randomly allocated to treatment with either a single 600 mg dose or a standard five-day course of trimethoprim. Twenty-seven of 30 women were cured with a single dose. Six of these 27 women were reinfected later in the pregnancy. Twenty-four of 30 women treated with a five-day course of trimethoprim were cured, and five became reinfected later in the pregnancy. One women vomited the single dose. There were no detrimental effects on the outcome of the pregnancies. Single dose therapy should be considered as the treatment of choice for asymptomatic bacteriuria in pregnancy.  相似文献   
17.
With increasing numbers of cystic fibrosis (CF) patients surviving to adulthood, issues related to vocation inevitably arise and warrant specific attention. We examined the percentage of participants with CF currently working and explored risk factors for work disability among adults with CF. METHOD: We recruited 50 consecutive patients from an adult cystic fibrosis service. Demographic, employment history, illness severity indicators and CF-attributed work disability factors were evaluated. Demographic risk factors for work disability using the illness severity measures of FEV(1), S-K score, CRDQ, and recent hospitalisation as independent variables were determined. RESULTS: Factorial analysis of a disability index (DI) indicated no dependency on FEV(1) or S-K score, but dependency on quality of life indices (p<0.05), age (p<0.05) and hospital admission rate (p<0.05). Hours worked per week were dependent on quality of life (p<0.01) (mastery of disease domain), fewer hospital admissions (p<0.01) and age (p<0.05). Sixty-eight percent of the sample reported that CF resulted in significant impediments to employment. However, few had sought vocational guidance (6%). CONCLUSION: Determinants of workforce participation shows that hours worked and perceived disability are more dependent on mastery of disease, age, and time in hospital, than on clinical severity scores. Health professionals may assist productivity through career counselling or tailored programs.  相似文献   
18.
19.
Multimodality medical imaging enables measurement of the three-dimensional spatial distribution of a radiolabeled aerosol within the lung. Using a conceptual spatial morphological model these data may be transformed to provide information on deposition per airway generation. This methodology has been used to study the intrapulmonary deposition patterns of two formulations of a metered dose inhaler and two nebulizers in control subjects. The nebulizer study has also been stimulated using a computer model of deposition. The comparison between derived experimental results and those from computer modeling shows areas of agreement, although there are also areas of discrepancy. The new methodology has considerable potential value in the fields of inhalation therapy and deposition modeling, although more detailed validation is still required.  相似文献   
20.
As more patients survive cancer, and as more sophisticated multidrug antineoplastic protocols are developed, the chances of an anesthesiologist's coming into contact with patients who have been treated with such protocols are increasing. The anesthesiologist who must administer anesthesia to a patient who has had chemotherapy must be cognizant of the particular antineoplastic agents that have the potential for producing occult pulmonary dysfunction. Anesthetic management of these cases must be carefully planned and titrated to prevent further lung injury.  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