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   4262篇
  免费   360篇
  国内免费   9篇
耳鼻咽喉   154篇
儿科学   138篇
妇产科学   151篇
基础医学   551篇
口腔科学   48篇
临床医学   499篇
内科学   677篇
皮肤病学   23篇
神经病学   415篇
特种医学   84篇
外科学   511篇
综合类   79篇
一般理论   11篇
预防医学   525篇
眼科学   63篇
药学   317篇
肿瘤学   385篇
  2023年   32篇
  2022年   58篇
  2021年   114篇
  2020年   106篇
  2019年   136篇
  2018年   143篇
  2017年   104篇
  2016年   124篇
  2015年   145篇
  2014年   187篇
  2013年   233篇
  2012年   403篇
  2011年   355篇
  2010年   173篇
  2009年   138篇
  2008年   246篇
  2007年   258篇
  2006年   247篇
  2005年   253篇
  2004年   221篇
  2003年   206篇
  2002年   157篇
  2001年   49篇
  2000年   40篇
  1999年   49篇
  1998年   39篇
  1997年   16篇
  1996年   20篇
  1995年   18篇
  1994年   10篇
  1993年   12篇
  1992年   22篇
  1991年   25篇
  1990年   18篇
  1989年   22篇
  1988年   16篇
  1987年   20篇
  1986年   12篇
  1985年   13篇
  1984年   10篇
  1983年   11篇
  1982年   18篇
  1981年   14篇
  1980年   19篇
  1979年   11篇
  1978年   10篇
  1977年   10篇
  1976年   11篇
  1973年   13篇
  1972年   11篇
排序方式: 共有4631条查询结果,搜索用时 31 毫秒
991.
992.

Purpose

To investigate the implications of a cancer diagnosis on medication adherence for pre-existing comorbid conditions, we explored statin adherence patterns prior to and following a new diagnosis of breast, colorectal, or prostate cancer among a multi-ethnic cohort.

Methods

We identified adults enrolled at Kaiser Permanente Northern California who were prevalent statin medication users, newly diagnosed with breast, colorectal, or prostate cancer between 2000 and 2012. Statin adherence was measured using the proportion of days covered (PDC) during the 2-year pre-cancer diagnosis and the 2-year post-cancer diagnosis. Adherence patterns were assessed using generalized estimating equations, for all cancers combined and stratified by cancer type and race/ethnicity, adjusted for demographic, clinical, and tumor characteristics.

Results

Among 10,177 cancer patients, statin adherence decreased from pre- to post-cancer diagnosis (adjusted odds ratio (ORadj):0.91, 95% confidence interval (95% CI):0.88–0.94). Statin adherence decreased from pre- to post-cancer diagnosis among breast (ORadj:0.94, 95% CI:0.90–0.99) and colorectal (ORadj:0.79, 95% CI:0.74–0.85) cancer patients. No difference in adherence was observed among prostate cancer patients (ORadj:1.01, 95% CI:0.97–1.05). Prior to cancer diagnosis, adherence to statins was generally higher among non-Hispanic whites and multi-race patients than other groups. However, statin adherence after diagnosis decreased only among these two populations (ORadj:0.85, 95% CI:0.85–0.92 and ORadj:0.86, 95% CI:0.76–0.97), respectively.

Conclusions

We found substantial variation in statin medication adherence following diagnosis by cancer type and race/ethnicity among a large cohort of prevalent statin users in an integrated health care setting.

Implications for Cancer Survivors

Improving our understanding of comorbidity management and polypharmacy across diverse cancer patient populations is warranted to develop tailored interventions that improve medication adherence and reduce disparities in health outcomes.
  相似文献   
993.
Purpose/objective(s)

Brain metastasis velocity (BMV) is a metric that describes the rate of development of new brain metastases (BM) after initial stereotactic radiosurgery (SRS). A limitation in the application of BMV is it cannot be applied until time of first BM failure after SRS. We developed initial BM velocity (iBMV), a new metric that accounts for the number of BM at first SRS and the time since initial cancer diagnosis.

Materials/methods

We reviewed patients with BM treated at our institution with upfront SRS without WBRT. iBMV was calculated as the number of BM at initial SRS divided by time (years) from initial cancer diagnosis to first SRS. We performed a linear regression to correlate BMV as a continuous variable and with low, intermediate, and high BMV risk groups. Kaplan–Meier estimation of OS was calculated from time of first SRS to death. iBMV was not calculated for patients who presented with BM at initial cancer diagnosis.

Results

994 patients were treated with upfront SRS without WBRT between 2000 and 2017. Median OS was 8.5 mos. 595 (60%) patients developed BM after cancer diagnosis and median time to first SRS from time of initial diagnosis was 2.2 years. Median iBMV was 0.79 BM/year. iBMV correlated with BMV (β?=?1.57 p?=?0.021) and independently predicted for mortality [Cox proportional hazard ratio (HR) 1.11, p?=?0.036] after accounting for histology, number of initial brain metastases (HR 1.03, p?=?0.32), time from cancer diagnosis to SRS (HR 0.98, p?=?0.157) in a multivariate model.

Conclusion

iBMV correlates with BMV and OS. With further validation, iBMV could serve as a metric to risk stratify patients for WBRT or SRS at time of first BM presentation.

  相似文献   
994.
The human papillomavirus (HPV) can cause anogenital cancers and genital warts; however, it can be prevented through the HPV vaccine, which has been available since 2006. While this vaccine is targeted toward 11-to-12-year-olds, 18-to-26-year-old young adult women are eligible for “catch-up” vaccination. Knowledge of HPV may impact HPV vaccine uptake among this population. The purpose of this study was to assess changes in HPV knowledge and HPV vaccine information sources among young adult college women over a 7-year period. Two independent samples (N?=?223 for 2008; N?=?323 for 2015) completed a 23-item knowledge scale and survey regarding HPV. Adjusted logistic regression models compared the odds of correctly answering each knowledge item between each time period. The study found that HPV knowledge increased significantly over time (p?<?0.01). The participants in 2015 were more likely than the 2008 participants to accurately report that a condom can decrease the chance of HPV transmission; there is a vaccine for women that prevents certain types of HPV; HPV can cause genital warts; HPV can be passed to a newborn at birth; and even if you do not see a wart, you can transmit HPV. Recent participants were also more likely to correctly report only women can get HPV as false. While improvements in HPV knowledge were found over time, misperceptions regarding outcomes associated with HPV persist. In order to promote HPV vaccination among this population, health literacy skills, in addition to knowledge, should be improved.  相似文献   
995.

Purpose

The accumulation of p53 and bcl-2 gene products as well as the loss of the retinoblastoma (Rb) gene product have been associated with prostate cancer progression. We assessed whether the levels of immunoreactivity for p53, Rb and bcl-2 are better long-term predictors of disease specific survival than conventional pathological parameters of the primary tumor, such as Gleason score, capsular penetration, seminal vesicle invasion, and percent tumor in the specimen, in patients with clinically localized prostate cancer treated with radical prostatectomy.

Materials and Methods

A total of 71 patients with clinical stages A1 to B2 adenocarcinoma of the prostate underwent radical prostatectomy after a negative metastatic evaluation. No neoadjuvant or adjuvant treatments were given and causes of death were recorded. Prostatectomy specimens were analyzed to determine the conventional pathological parameters, and p53, Rb and bcl-2 immunohistochemical staining. Univariate and multivariate analyses were done to determine the independent contributions of p53, Rb and bcl-2 in predicting survival.

Results

On multivariate analysis the independent factors predicting disease specific survival were p53 staining score (p <0.001) and Rb staining score (p <0.001). In patients with p53 immunoreactive tumors the 15-year disease specific survival was 38% compared to 87% for those with less immunoreactivity. Analysis of Rb immunoreactivity for 15-year disease specific survival yielded 92 and 66% high and low staining levels, respectively. Best subset analysis revealed that the combination of p53 score and Rb score yielded the best predictive value for disease specific survival.

Conclusions

p53 and Rb immunohistochemical staining scores were independent predictors of disease specific survival and were superior to conventional pathological prognostic factors of the primary tumor. These findings lay the groundwork for the prospective study of these markers in patients treated with radical prostatectomy.  相似文献   
996.
INTRODUCTION: Gynecological sarcomas are rare and have a poor prognosis. Uterine sarcomas are most common accounting for 4% of all uterine tumors. Ovarian sarcomas are less frequent and are usually carcinosarcomas. CASE REPORT: A previously healthy 40-year-old G2P2 presented for evaluation of 72 h of right upper quadrant pain and shortness of breath. A malignant right pleural effusion, ascites, and adnexal mass were found. Surgical staging and suboptimal debulking revealed pure angiosarcoma of the ovary Stage IV. DISCUSSION: There are 12 cases of ovarian angiosarcoma reported in the literature. Ten of these cases presented in advanced stages with survivals of 2-30 months. Various chemotherapy regimens have been tried on these tumors including the most recent recommendation of MAID (mesna, doxorubicin, ifosfamide, and dacarbazine) and prognosis remains poor. Our patient underwent elective right pleurodesis via video-assisted thorascopic surgery under local anesthesia for an early recurrent right pleural effusion and subsequently began MAID chemotherapy.  相似文献   
997.
Traditional and complementary medicine (T&CM) strategies are widely utilized in pediatric oncology, with many families reporting T&CM use with the intention to cure cancer. Study of T&CM agents presents many challenges, as a heterogeneous group of agents and techniques are used for a variety of different purpose in many different oncologic conditions. We present a systematic review of the literature examining published reports in which T&CM agents are used with an intention of cure. Twenty‐two reports were identified, with most reports being of poor quality. Novel paradigms are likely needed to further investigate T&CM agents.  相似文献   
998.
Physical inactivity has been shown to exacerbate negative side effects experienced by pediatric patients undergoing cancer therapy. Exercise interventions are being created in response. This review summarizes current exercise intervention data in the inpatient pediatric oncology setting. Two independent reviewers collected literature from three databases, and analyzed data following the PRISMA statement for systematic reviews and meta‐analyses. Ten studies were included, representing 204 patients. Good adherence, positive trends in health status, and no adverse events were noted. Common strategies included individual, supervised, combination training with adaptability to meet fluctuating patient abilities. We recommend that general physical activity programming be offered to pediatric oncology inpatients.  相似文献   
999.
OSHA revised the 1971 respiratory protection standard in 1998 to add guidance for selecting and maintaining respirators. Fatality reports from 1990 to 2012 were used to characterize historical trends in fatalities associated with respirators. Industry- and time-specific trends were evaluated to determine the effect of the revision to the standard on respirator-related fatalities; 174 respirator-related deaths were reported. The majority of fatalities were associated with using an airline respirator (n = 34) or the absence of using a respirator in required spaces (n = 38). Overall, 79% of fatalities were associated with asphyxia. Fatalities were associated with improper employee use or lack of employer compliance. Reductions in fatality rates over time appeared to be associated with the revisions to the respirator standard, although other variables may influence rates (eg, controls). Recommendations for employers and employees regarding maintaining safe use of respirators are provided.  相似文献   
1000.

Purpose

A major challenge facing nanoparticle-based delivery of chemotherapy agents is the natural and unavoidable accumulation of these particles in healthy tissue resulting in local toxicity and dose-limiting side effects. To address this issue, we have designed and characterized a new prodrug nanoparticle with controllable toxicity allowing a locally-delivered light trigger to convert the payload of the particle from a low to a high toxicity state.

Methods

The nanoparticles are created entirely from light-activatable prodrug molecules using a nanoprecipitation process. The prodrug is a conjugate of doxorubicin and photocleavable biotin (DOX-PCB).

Results

These DOX-PCB nanoparticles are 30 times less toxic to cells than doxorubicin, but can be activated to release pure therapeutic doxorubicin when exposed to 365 nm light. These nanoparticles have an average diameter of around 100 nm and achieve the maximum possible prodrug loading capacity since no support structure or coating is required to prevent loss of prodrug from the nanoparticle.

Conclusions

These light activatable nanoparticles demonstrate tunable toxicity and can be used to facilitate future therapy development whereby light delivered specifically to the tumor tissue would locally convert the nanoparticles to doxorubicin while leaving nanoparticles accumulated in healthy tissue in the less toxic prodrug form.
  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