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   6217篇
  免费   260篇
  国内免费   31篇
耳鼻咽喉   32篇
儿科学   73篇
妇产科学   30篇
基础医学   682篇
口腔科学   122篇
临床医学   341篇
内科学   1836篇
皮肤病学   38篇
神经病学   621篇
特种医学   263篇
外科学   1106篇
综合类   17篇
预防医学   110篇
眼科学   71篇
药学   313篇
中国医学   16篇
肿瘤学   837篇
  2023年   46篇
  2022年   88篇
  2021年   192篇
  2020年   92篇
  2019年   118篇
  2018年   149篇
  2017年   111篇
  2016年   167篇
  2015年   166篇
  2014年   208篇
  2013年   240篇
  2012年   392篇
  2011年   420篇
  2010年   233篇
  2009年   187篇
  2008年   351篇
  2007年   349篇
  2006年   360篇
  2005年   366篇
  2004年   377篇
  2003年   367篇
  2002年   329篇
  2001年   79篇
  2000年   67篇
  1999年   88篇
  1998年   83篇
  1997年   73篇
  1996年   67篇
  1995年   78篇
  1994年   42篇
  1993年   59篇
  1992年   76篇
  1991年   55篇
  1990年   54篇
  1989年   59篇
  1988年   37篇
  1987年   27篇
  1986年   39篇
  1985年   19篇
  1984年   21篇
  1983年   24篇
  1982年   9篇
  1981年   14篇
  1980年   11篇
  1979年   14篇
  1977年   10篇
  1975年   11篇
  1974年   9篇
  1972年   10篇
  1971年   10篇
排序方式: 共有6508条查询结果,搜索用时 350 毫秒
961.
We investigated glycemic stability and insulin requirement 1 month after a single transplantation of the islets from non-heart-beating donors or a living donor. Overall blood glucose levels decreased immediately after transplantation. The M-value and mean amplitude of glycemic excursions (MAGE) decreased significantly from 53.0 (range, 8.9-91.0) to 4.2 (0.6-8.8, P<0.05) and from 8.5 mM (4.8-11.7) to 3.3 mM (2.0-4.5, P<0.05), respectively. The values after transplantation were lower than the first quartile of 102 type 2 diabetic control patients. The estimated HbA1c level decreased significantly from 7.9% (5.7-10.9) to 5.4% (4.7-5.9, P<0.05). The supplement of basal insulin decreased 43% from 0.31 units/kg/day (0.16-0.37) to 0.18 units/kg/day (0-0.22, P<0.05), while that of stimulated insulin did not decrease significantly, from 0.28 units/kg/day (0.13-0.51) to 0.21 units/kg/day (0-0.41). Thus, only one islet transplantation can be sufficient to attain metabolic stability, probably by effective supply of basal insulin secretion, sufficient to avoid life-threatening severe hypoglycemia and prevent or delay the progress of secondary complications of diabetes by decreasing the HbA1c level.  相似文献   
962.
BACKGROUND/AIMS: Both the incidence of diabetes mellitus (DM) and mortality from Hepatocellular carcinoma (HCC) are increasing in Japan. As the association of overall cancer and HCC with impaired glucose tolerance (IGT) has been studied rarely in the world including Japan, this study assessed their associations using cohort data of Hokkaido, Japan. METHODOLOGY: After getting ethical consent, this study included 908 men and 1,081 women aged 30-77 years during 1977-78 and collected detailed information using the baseline survey. The subjects were followed until 2002 and deaths were recorded using ICD-9. Classifying them into three groups of diabetes status namely DM, IGT, and normal, the relative risk (RR) of mortality was estimated by diabetes status using multivariate Cox model. RESULTS: This study revealed no association between overall cancer and diabetes status. However, the RR of mortality from HCC was about 11 times (HR= 10.8, 95%CI: 1.3-92.5) higher in IGT compared with normal group. DM group also showed higher risk of mortality than normal group. CONCLUSIONS: HCC mortality was significantly high among IGT group. However, as the results of the study were based on small data, further studies with large cohort are needed to address the association of IGT with overall cancer and HCC mortality in Japan.  相似文献   
963.
Topical application of siRNA to the skin should be an effective treatment for serious skin disorders, such as atopic dermatitis. However, it is difficult to introduce hydrophilic macromolecules, including siRNA, into the skin by conventional methods. For efficient delivery of siRNA, we examined an iontophoretic technique, since it is suitable for the delivery of charged molecules. Naked siRNA effectively accumulated in the epidermis (and not in the dermis) after iontophoretic delivery. In contrast, siRNA did not penetrate tape-stripped skin by passive diffusion. In a rat model of atopic dermatitis, skin was sensitized with ovalbumin to stimulate IL-10 mRNA expression as observed in skin lesions. Iontophoretic delivery of anti-IL-10 siRNA significantly reduced (73%) the level of IL-10 mRNA. In conclusion, we successfully delivered naked siRNA into the epidermis and concomitantly suppressed the expression of an endogenous immuno-regulatory cytokine.  相似文献   
964.
A simple radiochemical choline acetyltransferase (ChAT) assay screening test was developed by measuring for [(3)H]acetylcholine ([(3)H]ACh) formed from 0.2 mM [(3)H]acetyl-coenzyme A ([(3)H]acetyl-CoA) and 1 mM choline by 0.2 mg of rat brain homogenates containing ChAT into 96-well microplates. A simple and rapid procedure for isolating [(3)H]ACh from the incubation mixture into 96-well microplates was achieved by using a sodium tetraphenylboron (Kalibor) solution (in ethyl acetate, 0.75%, w/v) and a hydrophobic liquid scintillator mixture (1:5, v/v, 0.2 mL) as an extraction solvent. The benefits of this radiochemical method using 96-well microplates are as follows: (1) this method is reliable and reproducible; (2) many samples can be examined at the same time by this method; (3) this method is economical and effective in reducing radioactive waste. The development of a new simple radiochemical ChAT assay screening test is the first stage of development of radiolabeled ChAT mapping agent.  相似文献   
965.

Purpose

Five prognostic factors had been previously identified in patients with metastatic colorectal cancer (MCRC) who received irinotecan-based second-line chemotherapy. Patients were classified into three prognostic groups based on significant differences in median overall survival (OS). This study is conducted to validate this classification in an external validation cohort.

Methods

This retrospective study included 193 patients of an external validation cohort who received irinotecan-based second-line chemotherapy after first-line oxaliplatin-based chemotherapy, with or without bevacizumab at three institutions.

Results

Three of the five predefined factors (poorly differentiated adenocarcinoma, LDH ≥400 IU/L, progression-free survival of first-line therapy <6 months) remained highly significant in the validation cohort, although two (performance status 2 and peritoneal metastasis) were associated with borderline significance. The distribution of the three prognostic groups (low risk = no factors, intermediate risk = 1 factor, high risk = 2 or more factors) was low risk (n = 68; 35 %), intermediate risk (n = 80; 41 %), and high risk (n = 45; 23 %). The median OS of each group were 19.8, 11.0, and 7.9 months, respectively, with significant differences between groups, as found in the previous cohort.

Conclusion

The previous prognostic classification of patients with MCRC who received irinotecan-based second-line chemotherapy was validated in another independent cohort. Validation in prospective studies is warranted.  相似文献   
966.
967.
968.
969.
Impaired liver regeneration after partial hepatectomy in db/db mice   总被引:1,自引:0,他引:1  
Fatty liver is the most common hepatic disorder in humans and supposed to be a cause of poor prognosis after liver transplantation and hepatic resection which could be resulted from impaired liver regeneration. This study was carried out to analyze the process of liver regeneration in db/db mice which show severe steatosis because of abnormal leptin receptor. We performed 70% partial hepatectomy (PH) on db/db mice and normal +m/+m mice, and then sacrificed the animals 1, 2, 3, 5, 7 and 10 days later. The liver samples were weighed and examined histologically or immunohistochemically. As a result, the liver mass restitution was significantly inhibited in db/db mice compared with +m/+m mice. The BrdU labelling index peaked at 2 days after PH in both strains, although the value was lower in db/db mice. After that, interestingly, it decreased to the control level at 5 days in +m/+m mice while the recovery was delayed in db/db mice. Similar sequence was also observed in the PCNA labelling index. In addition, the peak time of the mitosis index was 2 days and 5 days after PH in +m/+m mice and in db/db mice, respectively. Thus, although not significant, the proliferative response of hepatocytes to PH occurred somewhat more transient and sharply in +m/+m mice while it lasted somewhat longer in db/db mice. This suggests that db/db mice may be valuable as one of the animal models for the investigation of the effects of steatosis on the liver regeneration.  相似文献   
970.
The spv genes carried on the Salmonella virulence plasmid are commonly associated with severe systemic infection in experimental animals. The SpvB virulence-associated protein has been shown to ADP-ribosylate actin, and this enzymatic activity is essential for virulence in mice. Here, we present evidence that intracellular expression of SpvB protein induces not only disruption of actin filaments but also apoptotic cell death in eukaryotic cells.  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