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   2756733篇
  免费   185324篇
  国内免费   7572篇
耳鼻咽喉   35487篇
儿科学   91479篇
妇产科学   74651篇
基础医学   381103篇
口腔科学   71146篇
临床医学   245853篇
内科学   545296篇
皮肤病学   63170篇
神经病学   228580篇
特种医学   108400篇
外国民族医学   736篇
外科学   415113篇
综合类   52859篇
现状与发展   5篇
一般理论   968篇
预防医学   212387篇
眼科学   59273篇
药学   197056篇
  8篇
中国医学   5955篇
肿瘤学   160104篇
  2021年   20010篇
  2019年   20644篇
  2018年   49437篇
  2017年   38570篇
  2016年   44941篇
  2015年   30419篇
  2014年   41135篇
  2013年   61063篇
  2012年   86467篇
  2011年   103802篇
  2010年   68063篇
  2009年   59889篇
  2008年   97589篇
  2007年   105209篇
  2006年   86046篇
  2005年   84138篇
  2004年   82574篇
  2003年   81143篇
  2002年   76435篇
  2001年   128770篇
  2000年   131920篇
  1999年   110719篇
  1998年   31485篇
  1997年   28205篇
  1996年   28358篇
  1995年   27533篇
  1994年   25242篇
  1993年   23547篇
  1992年   85265篇
  1991年   81727篇
  1990年   78945篇
  1989年   76173篇
  1988年   69568篇
  1987年   68094篇
  1986年   63619篇
  1985年   60603篇
  1984年   44992篇
  1983年   37999篇
  1982年   22542篇
  1981年   19994篇
  1979年   39050篇
  1978年   27499篇
  1977年   23266篇
  1976年   21549篇
  1975年   22818篇
  1974年   26824篇
  1973年   25379篇
  1972年   23750篇
  1971年   21955篇
  1970年   20213篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
123.
Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. 18F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, 18F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to 18F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [18F]APPs.  相似文献   
124.
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception.  相似文献   
125.
126.
127.
128.
129.

Aims

To examine the influence of pre-existing psychiatric disorder on the choice of treatment in patients with gynaecological cancer.

Materials and methods

The analyses were based on all patients who underwent surgical treatment for endometrial, ovarian or cervical cancer who were registered in the Danish Gynecological Cancer Database in the years 2007–2014 (3059 patients with ovarian cancer, 5100 patients with endometrial cancer and 1150 with cervical cancer). Logistic regression model and Cox regression model, adjusted for relevant confounders, were used to estimate the effect of pre-existing psychiatric disorder on the course of cancer treatment. Our outcomes were (i) presurgical oncological treatment, (ii) macroradical surgery for patients with ovarian cancer, (iii) radiation/chemotherapy within 30 days and 100 days after surgery and (iv) time from surgery to first oncological treatment.

Results

In the group of patients with ovarian cancer, more patients with a psychiatric disorder received macroradical surgery versus patients without a psychiatric disorder, corresponding to an adjusted odds ratio of 1.24 (95% confidence interval 0.62–2.41) and the chance for having oncological treatment within 100 days was odds ratio = 1.26 (95% confidence interval 0.77–2.10). As for patients with endometrial cancer, all outcome estimates were close to unity. The adjusted odds ratio for oncological treatment within 30 days after surgery in patients with cervical cancer with a history of psychiatric disorder was 0.20 (95% confidence interval 0.03–1.54).

Conclusions

We did not find any significant differences in the treatment of ovarian and endometrial cancer in patients with pre-existing psychiatric diagnoses. When it comes to oncological treatment, we suggest that increased attention should be paid to patients with cervical cancer having a pre-existing psychiatric diagnosis.  相似文献   
130.
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