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   8828篇
  免费   507篇
  国内免费   14篇
耳鼻咽喉   94篇
儿科学   293篇
妇产科学   218篇
基础医学   1367篇
口腔科学   395篇
临床医学   815篇
内科学   1697篇
皮肤病学   263篇
神经病学   893篇
特种医学   365篇
外科学   1240篇
综合类   62篇
一般理论   10篇
预防医学   517篇
眼科学   76篇
药学   550篇
中国医学   12篇
肿瘤学   482篇
  2022年   52篇
  2021年   126篇
  2020年   96篇
  2019年   107篇
  2018年   130篇
  2017年   111篇
  2016年   148篇
  2015年   156篇
  2014年   209篇
  2013年   290篇
  2012年   423篇
  2011年   418篇
  2010年   264篇
  2009年   273篇
  2008年   435篇
  2007年   430篇
  2006年   407篇
  2005年   451篇
  2004年   381篇
  2003年   391篇
  2002年   391篇
  2001年   282篇
  2000年   243篇
  1999年   216篇
  1998年   107篇
  1997年   107篇
  1996年   85篇
  1995年   69篇
  1994年   66篇
  1993年   61篇
  1992年   122篇
  1991年   106篇
  1990年   111篇
  1989年   118篇
  1988年   105篇
  1987年   126篇
  1986年   108篇
  1985年   99篇
  1984年   83篇
  1983年   76篇
  1982年   60篇
  1981年   51篇
  1978年   61篇
  1977年   55篇
  1976年   63篇
  1973年   56篇
  1971年   48篇
  1969年   51篇
  1968年   48篇
  1966年   51篇
排序方式: 共有9349条查询结果,搜索用时 31 毫秒
1.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
2.
3.
4.
PURPOSE: To analyze the effectiveness of surgery and chemotherapy with or without radiotherapy in the management of limited small cell lung cancer (LSCLC) in stages I and II. PATIENTS AND METHODS: 39 patients (median age 62 years) with LSCLC in stages pT1 or pT2 and pN0 or pN1 (stages IA-IIB) who had a tumor resection and systematic lymph node dissection were reviewed retrospectively. The median follow-up period was 29 months. 35 patients (90%) received a median of four cycles of a platinum-containing chemotherapy postoperatively. 16 patients (41%) received an adjuvant thoracic radiotherapy (TRT, median 50 Gy); 21 patients (54%) received a prophylactic cranial irradiation (PCI, median 30 Gy). RESULTS: The median overall survival for all patients was 47 months, resulting in actuarial 1-, 3-, and 5-year survival rates of 97%, 58%, and 49%, respectively. Distant metastases were found in 13 patients (33%) after a median of 16 months. Patients who received an adjuvant TRT showed a trend toward improved thoracic recurrence-free survival (p = 0.06) and improved overall survival (p = 0.07) compared to those treated with surgery and chemotherapy only. Brain metastasis-free survival (p = 0.01) and overall survival (p = 0.01) were improved significantly in patients who received a PCI. CONCLUSION: Surgical tumor resection may be considered for carefully selected patients. Adjuvant chemotherapy and PCI are recommended for all patients. Adjuvant TRT is currently used in patients with positive lymph nodes (pN1), because the probability of a subclinical involvement of the mediastinal lymphatic system appears to be increased in these patients.  相似文献   
5.
6.
Quantitative immunoblotting assay of blood coagulation factor XII   总被引:2,自引:0,他引:2  
The immunoblotting technique was applied to the study of Factor XII (F.XII) in plasma. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole plasma followed by electroblotting of the electropherograms to nitrocellulose (NC) membranes and immunologic detection by a double antibody technique was used. 125-F.XII was transferred to the NC membrane in amounts proportional to the amount applied to the gel provided that a constant amount of carrier protein was present. Based on this, a quantitative assay was developed using either normal plasma or F.XII dilutions in F.XII-deficient plasma as standards. The measurement of F.XII antigen by immunoblotting was reproducible and gave values similar to those obtained by radial immunodiffusion. Two normal plasma pools contained 26 and 29 μ/ml of F.XII according to the immunoblotting assay. Compared to other immunoassays, immunoblotting has the advantage of directly estimating the apparent molecular weight (MW) of the protein of interest. Thus, we could confirm the normal apparent MW (80,000) of a F.XII-like molecule previously isolated from a cross reacting material (CRM)-positive F.XII-deficient plasma. None of eight CRM-negative F.XII-deficient plasmas showed an 80,000 MW immunoreactive molecule. However, five of these eight plasmas had a faint autoradiographic band at 115,000 MW that was similarly seen in only three out of 43 individual normal plasmas. The nature of this 115,000 MW band remains to be defined.  相似文献   
7.
Cholangiocarcinomas (CC) frequently demonstrate lymphatic spread. We investigated lymph node (LN) counts after resection of extrahepatic CC and survival based on the SEER 1973–2004 database. Out of 20,068 CC patients, 1,518 individuals were selected based on M0 stage and at least one LN examined. Primary cancer sites included gallbladder (29%), extrahepatic bile ducts (26%), and intrapancreatic/ampullary bile ducts (45%); 42% of patients were LN-positive. The median number of LNs examined was four (range 1–39). Median survival was 37 months for LN-negative and 16 months for LN-positive cancers. Multivariate prognostic variables were the number of positive LNs, primary site, age (all at p < 0.0001), gender (p = 0.002), size (p = 0.005), T category (p = 0.009), and total LN count (or number of negative LNs obtained, p = 0.01). The impact of total LN counts was seen in LN-negative (median survival, 1 vs 10 or more LNs examined: 27 vs 51 months, p = 0.002) and LN-positive disease (10 vs 22 months, p < 0.0001). Survival prediction of extrahepatic CCs is strongly influenced by total LN counts and numbers of negative LNs obtained. Although the resulting incremental benefit is small, dissection and examination of 10 or more LNs should be considered for curative intent resections.  相似文献   
8.
9.
Re-epithelialization of cutaneous wounds is a coordinated process of proliferation and migration of keratinocytes at the wound edge. The study objective was to identify the differences in epidermal morphology, keratinocyte proliferation and matrix molecules (laminin 1, laminin 5, type IV collagen) and their specific integrin (α3, α6) expression in biopsies of meshed split thickness grafted and chronic wounds. The mean mitotic index of keratinocytes (ratio of cell cycle associated antigen Ki-67 expressing keratinocytes to basal keratinocytes) was highest in chronic wounds (38.7%) compared to acute wounds (22.25%, range 5.7% to 54%). The mean thickness of the hyper-proliferative epithelium at the wound edge of chronic wounds was 0.69 mm compared to 0.15 mm at the wound margin of split thickness grafted wounds. Both chronic wounds and skin grafted wounds exhibited strong laminin 5 immunoreactivity at the basal side of the epithelium, which extended under the most forward keratinocytes. Laminin 1 and type IV collagen immunoreactivity did not extend to the wound margin in either skin grafted or chronic wounds. In both transplanted skin and chronic wounds, the integrin sub-units α3 and α6 exhibited a strong pericellular immunoreactivity on the leading keratinocytes of the wound margin. Our data demonstrates that the proliferation of keratinocytes and the expression of associated integrins are not impaired in chronic wounds. Presented at the 33rd Congress of the Association of German Plastic Surgeons, Germany, 18–21 September, 2002.  相似文献   
10.
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