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   7491篇
  免费   529篇
  国内免费   23篇
耳鼻咽喉   141篇
儿科学   425篇
妇产科学   173篇
基础医学   1079篇
口腔科学   73篇
临床医学   575篇
内科学   1647篇
皮肤病学   202篇
神经病学   350篇
特种医学   127篇
外科学   824篇
综合类   313篇
一般理论   2篇
预防医学   495篇
眼科学   205篇
药学   690篇
中国医学   38篇
肿瘤学   684篇
  2023年   63篇
  2022年   137篇
  2021年   264篇
  2020年   154篇
  2019年   167篇
  2018年   200篇
  2017年   150篇
  2016年   191篇
  2015年   219篇
  2014年   286篇
  2013年   343篇
  2012年   519篇
  2011年   502篇
  2010年   291篇
  2009年   259篇
  2008年   387篇
  2007年   350篇
  2006年   312篇
  2005年   290篇
  2004年   256篇
  2003年   238篇
  2002年   205篇
  2001年   190篇
  2000年   174篇
  1999年   133篇
  1998年   60篇
  1997年   49篇
  1996年   48篇
  1995年   47篇
  1994年   49篇
  1993年   47篇
  1992年   103篇
  1991年   93篇
  1990年   91篇
  1989年   70篇
  1988年   78篇
  1987年   75篇
  1986年   65篇
  1985年   68篇
  1984年   40篇
  1983年   43篇
  1979年   54篇
  1978年   41篇
  1976年   40篇
  1975年   38篇
  1974年   45篇
  1973年   37篇
  1972年   52篇
  1971年   37篇
  1970年   37篇
排序方式: 共有8043条查询结果,搜索用时 15 毫秒
91.
92.
93.

BACKGROUND:

The objective of this study was to compare the prognostic value of the sixth and seventh editions of the American Joint Cancer Committee (AJCC) Cancer Staging Manual and the risk‐stratification model of the National Comprehensive Cancer Network (NCCN).

METHODS:

Two‐thousand four hundred twenty‐nine men who received definitive radiotherapy with or without androgen‐deprivation therapy (median follow‐up, 74 months) were analyzed.

RESULTS:

There was a migration of stage II patients to stage I with AJCC seventh edition (stage I increased from 1% to 38%, and stage II decreased from 91% to 55%). One pair‐wise comparison (4%) of Kaplan‐Meier estimates of biochemical failure, distant metastasis, prostate cancer‐specific survival, and overall survival between stages was statistically significant for the AJCC sixth edition. Conversely, 16 of 24 comparisons (67%) were significant for the AJCC seventh edition. With the NCCN risk‐stratification model, 9 of 12 comparisons (75%) were significant. Concordance probability estimate (CPE) and standard error (SE) analysis indicated uniform and significant improvement in the predictive power of the AJCC seventh edition versus the sixth edition for all outcomes. CPE ± SE values for the AJCC seventh edition versus the sixth edition were 0.51 ± 0.009 versus 0.59 ± 0.02, respectively, for biochemical failure; 0.54 ± 0.02 versus 0.70 ± 0.05, respectively, for distant metastasis; 0.57 ± 0.009 versus 0.76 ± 0.007, respectively, for prostate cancer‐specific survival; and 0.52 ± 0.006 versus 0.57 ± 0.01, respectively, for overall survival. CPE ± SE values for the NCCN model were 0.59 ± 0.02 for biochemical failure, 0.72 ± 0.05 for distant metastasis, 0.80 ± 0.01 for prostate cancer‐specific survival, and 0.57 ± 0.01 for overall survival.

CONCLUSIONS:

The current results indicated that the seventh edition of the AJCC Cancer Staging Manual is a major improvement over the sixth edition, because it distributes patients better among the stages and is more prognostic. However, the NCCN model was superior to the AJCC seventh edition and remains the preferred method for risk‐based clinical management of prostate cancer with radiotherapy. Cancer 2012. © 2012 American Cancer Society.  相似文献   
94.
95.
96.
97.
The ubiquitous gram-positive bacterium Staphylococcus aureus occupies a unique niche in humans for its ability to survive both as a commensal and a life-threatening pathogen. Its complex relationship with the host and its ability to engender a throng of virulence factors, have hindered the development of a successful vaccine against it. The use of immunoadjuvants to enhance host immunity and prevent the shift from commensalism to pathogenicity is a rational approach for containing infection. The objective of this study was to understand the mechanisms by which alum and two phytol-derived immunoadjuvants, phytanol (PHIS-01) 1 and phytanyl chloride (PCl) 2 shape the interaction between S. aureus and its murine host. We studied the effects of the phytol derivatives, relative to alum, on the induction of inflammatory cytokines and chemokines, recruitment of CD11b+ cells, generation of specific anti-S. aureus antibodies and in vitro clearance of S. aureus. Our results showed that both PHIS-01 and PCl were stronger inducers of protective cytokines IL-17 and IL-1β than alum, and far exceeded alum in enhancing anti-S. aureus antibody response. However, both alum and the phytol derivatives (particularly PCl) promoted efficient recruitment of CD11b+ cells. Furthermore, PHIS-01, alum and to a lesser extent, PCl were able to up-regulate the expression of key inflammation-related genes that were highly down-regulated by S. aureus alone. In vitro killing assays showed that both PHIS-01 and PCl were far more potent than alum in promoting S. aureus clearance; this indicated their efficiency in shaping an effective anti-S. aureus immune microenvironment. In summary, our study provides evidence for the better effectiveness of phytol-derived immunoadjuvants over alum in enhancing anti-S. aureus immunity.  相似文献   
98.
A micro-level investigation of 983 pregnant women (aged 15–49 years) regarding sex determination and associated factors was carried out in a periurban region of Northern India. Among the women surveyed, 183 chose to use sex determination. The highest percentage of sex determination was among 30–39-year-old women, and general caste and family size were two risk factors associated with sex determination. Correcting imbalances in sex ratios at birth is a complex issue without easy answers, especially in patriarchal societies. Apart from raising awareness among decisionmakers, property rights in favor of women and strict vigilance and record of registration of ultrasound machines are necessary.  相似文献   
99.
ObjectiveUniversal salt iodization is an effective strategy to optimize population-level iodine. At the same time as salt-lowering initiatives are encouraged globally, there is concern about compromised iodine intakes. This study investigated whether salt intakes at recommended levels resulted in a suboptimal iodine status in a country where salt is the vehicle for iodine fortification.MethodsThree 24-h urine samples were collected for the assessment of urinary sodium and one sample was taken for urinary iodine concentrations (UICs) in a convenience sample of 262 adult men and women in Cape Town, South Africa. Median UIC was compared across categories of sodium excretion equivalent to salt intakes lower than 5, 5 to 9, and greater than or equal to 9 g/d.ResultsThe median UIC was 120 μg/L (interquartile range 75.3–196.3), indicating iodine sufficiency. Less one-fourth (23.2%) of subjects had urinary sodium excretion values within the desirable range (salt <5 g/d), 50.7% had high values (5–9 g/d), and 22.8% had very high values (≥9 g/d). No association between urinary iodine and mean 3 × 24-h urinary sodium concentration was found (r = 0.087, P = 0.198) and UIC status did not differ according to urinary sodium categories (P = 0.804).ConclusionIn a country with mandatory universal salt iodization, consumers with salt intakes within the recommended range (<5 g/d) are iodine replete, and median UIC does not differ across categories of salt intake. This indicates that much of the dietary salt is provided from non-iodinated sources, presumably added to processed foods.  相似文献   
100.
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