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   22395篇
  免费   1343篇
  国内免费   42篇
耳鼻咽喉   150篇
儿科学   702篇
妇产科学   735篇
基础医学   2803篇
口腔科学   305篇
临床医学   3617篇
内科学   3736篇
皮肤病学   203篇
神经病学   2335篇
特种医学   402篇
外科学   1982篇
综合类   257篇
一般理论   32篇
预防医学   3348篇
眼科学   325篇
药学   1292篇
中国医学   23篇
肿瘤学   1533篇
  2024年   15篇
  2023年   152篇
  2022年   228篇
  2021年   418篇
  2020年   289篇
  2019年   442篇
  2018年   544篇
  2017年   410篇
  2016年   458篇
  2015年   549篇
  2014年   753篇
  2013年   1128篇
  2012年   1657篇
  2011年   1805篇
  2010年   942篇
  2009年   844篇
  2008年   1541篇
  2007年   1677篇
  2006年   1559篇
  2005年   1546篇
  2004年   1544篇
  2003年   1403篇
  2002年   1392篇
  2001年   217篇
  2000年   138篇
  1999年   173篇
  1998年   260篇
  1997年   224篇
  1996年   157篇
  1995年   175篇
  1994年   157篇
  1993年   118篇
  1992年   101篇
  1991年   77篇
  1990年   54篇
  1989年   59篇
  1988年   55篇
  1987年   54篇
  1986年   35篇
  1985年   60篇
  1984年   54篇
  1983年   48篇
  1982年   59篇
  1981年   54篇
  1980年   32篇
  1979年   19篇
  1978年   16篇
  1977年   14篇
  1976年   8篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Positive Force Feedback Control of Muscles   总被引:5,自引:0,他引:5  
  相似文献   
104.

Purpose

We determined if prostate specific antigen (PSA) density and PSA slope alone or in combination could be used to predict which men with persistently elevated serum PSA and prior negative prostate biopsies will have prostate cancer on repeat evaluation.

Materials and Methods

In our PSA-1 data base we identified 327 men 50 years old or older with an initially negative prostate biopsy who had persistent PSA elevation, and compared those who did and did not have prostate cancer on subsequent serial prostatic biopsy.

Results

Of 70 men with a PSA density of 0.15 or more and PSA slope of 0.75 ng./ml. or more annually compared to 83 with a PSA density of less than 0.15 and PSA slope of less than 0.75 ng./ml. annually 32 (46 percent) and only 11 (13 percent), respectively, had prostate cancer on subsequent prostate biopsies (p less than 0.0001). In a hierarchical logistic regression analysis PSA density and PSA slope were predictive of prostate cancer on subsequent biopsy (p = 0.001 and 0.03, respectively). PSA density of 0.15 or more alone or PSA slope of 0.75 ng./ml. or more annually alone as the indicator for repeat biopsy would have missed 35 and 40 percent of cancers, respectively.

Conclusions

In men with persistently elevated serum PSA after an initially negative prostate biopsy, PSA density and PSA slope alone or in combination provide useful predictive information about the results of repeat prostate biopsies. However, these parameters are not sufficiently sensitive to identify all patients with detectable prostate cancer.  相似文献   
105.
Introduction     
Psychiatric Quarterly -  相似文献   
106.
Psychiatric syndromes are common in patients with traumatic brain injury. Patients may develop typical disorders of mood, anxiety, or psychosis, in addition to changes in personality and cognition. The frequency of these syndromes and potential pharmacologic treatments for these psychiatric syndromes are just coming to light. There are, unfortunately, a dearth of placebo-controlled trials to guide treatment, although numerous treatments are suggested in the literature. This article reviews the existing studies of clinical syndromes related to brain injury and possible pharmacologic treatments.  相似文献   
107.
PURPOSE: We conducted a pilot study assessing the effects of the selective estrogen receptor modulator, tamoxifen, on the pharmacokinetics, pharmacodynamics, and safety of the steroidal, irreversible aromatase inhibitor (AI), exemestane, when the two were coadministered in postmenopausal women with metastatic breast cancer. EXPERIMENTAL DESIGN: Patients with documented or unknown hormone receptor sensitivity were eligible. Patients received oral exemestane at 25-mg once daily. Starting day 15, oral tamoxifen at 20-mg once daily, was added. We measured plasma concentrations of exemestane, estrone, estrone sulfate, and estradiol after 14 days of exemestane monotherapy and after approximately 4 weeks of combination therapy. The incidence and severity of adverse events were assessed by physical examination and patient reporting. RESULTS: We treated 18 patients. All had received prior chemotherapy and/or hormonal therapy, eight and six, respectively, with single-agent selective estrogen receptor modulators or irreversible aromatase inhibitors; no hormonal therapy was given within 30 days of study entry. Plasma exemestane concentrations and estrone, estrone sulfate, and estradiol suppression were unchanged after approximately 4 weeks of tamoxifen coadministration. All drug-related adverse events were grades 1 or 2; none was unexpected. Although not a formal study end point, antitumor activity was noted, with two partial responses and four cases of stable disease among 17 evaluable patients after a 9-month median follow-up (range, 2.5-19 months). CONCLUSIONS: This pilot study provides evidence that coadministration of tamoxifen does not affect exemestane pharmacokinetics or pharmacodynamics and that the combination is well-tolerated and active. Further clinical investigation is warranted.  相似文献   
108.
PURPOSE: To determine whether children with localized gonadal malignant germ cell tumors (MGCT) stage II testicular and stages I and II ovarian treated with four cycles of standard-dose cisplatin combined with etoposide and low-dose bleomycin (PEB) have an event-free survival (EFS) of at least 85% without significant toxicity. PATIENTS AND METHODS: Between May 1990 and July 1995, eligible pediatric patients with stage II or recurrent from stage I (as a stage II) testicular MGCT and stages I and II ovarian MGCT were enrolled onto this Pediatric Oncology Group and Children's Cancer Group study. PEB chemotherapy consisted of bleomycin 15 U/m2 on day 1, cisplatin 20 mg/m2/d on days 1 to 5, and etoposide 100 mg/m2/d on days 1 to 5. Patients received four cycles of therapy at 21-day intervals. RESULTS: Seventy-four patients with a median age of 10.5 years (range, 8.7 months to 16.7 years) were enrolled. Primary sites included: stage II testicular (n = 17), stage I ovarian (n = 41), and stage II ovarian MGCT (n = 16). Treatment with standard PEB resulted in 6-year EFS of 95% and overall survival (OS) of 95.7%. EFS and OS by primary site were as follows: stage II testicular, 100% and 100%; stage I ovarian, 95.1% and 95.1%; and stage II ovarian, 87.5% and 93.8%, respectively. Two patients died from recurrent disease, and one patient died of secondary acute myelocytic leukemia. Infrequent grade 3 to 4 hematologic toxicity was reported. No grade 3 to 4 renal, pulmonary, or ototoxicity was observed. CONCLUSION: Combination chemotherapy with PEB results in excellent EFS and OS with minimal toxicity in children and adolescents with localized gonadal MGCT.  相似文献   
109.
110.
Although recruitment of ethnic and racial minorities in medical research has been evaluated in several studies, much less is known about the methods used to recruit these populations to participate in cancer genetics research. This report reviews the resources that have been used to identify and recruit ethnic and racial minorities to participate in hereditary breast cancer research. Overall, hospital-based resources were used most often to identify potential subjects, and active recruitment methods were used most frequently to enroll eligible subjects. This review suggests that there appears to be a finite number of resources and strategies to identify and recruit potential subjects to participate in cancer genetics research; however, options for improving awareness about cancer genetics research among ethnic and racial minorities have not been extensively evaluated. To study ethnic and racial minority participation in cancer genetics research, stronger evaluation components will need to be integrated into research methods. Both observational and experimental studies are needed to determine resources that are most effective for identifying potential subjects who are ethnic and racial minorities and to evaluate the effects of different recruitment strategies on enrollment decisions among these populations.  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