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   696篇
  免费   23篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   15篇
妇产科学   4篇
基础医学   57篇
口腔科学   1篇
临床医学   25篇
内科学   271篇
皮肤病学   5篇
神经病学   12篇
特种医学   14篇
外科学   64篇
综合类   5篇
预防医学   41篇
眼科学   40篇
药学   39篇
中国医学   3篇
肿瘤学   112篇
  2024年   1篇
  2023年   2篇
  2022年   14篇
  2021年   21篇
  2020年   3篇
  2019年   6篇
  2018年   17篇
  2017年   8篇
  2016年   11篇
  2015年   24篇
  2014年   28篇
  2013年   39篇
  2012年   52篇
  2011年   55篇
  2010年   40篇
  2009年   29篇
  2008年   45篇
  2007年   42篇
  2006年   60篇
  2005年   38篇
  2004年   30篇
  2003年   40篇
  2002年   36篇
  2001年   4篇
  2000年   4篇
  1999年   6篇
  1998年   12篇
  1997年   11篇
  1996年   2篇
  1995年   7篇
  1994年   1篇
  1993年   3篇
  1992年   2篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1978年   3篇
  1976年   3篇
  1975年   2篇
  1974年   3篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有721条查询结果,搜索用时 15 毫秒
41.
Allen MW  Baines S 《Appetite》2002,38(2):118-130
The present study tested the extent to which dietary preferences are altered by making aspects of the symbolic meaning of meat salient to participants. Individuals in the treatment group were informed of a previous scientific study which found that people who endorse social hierarchy and human dominance over nature consume more red and white meat, and that people who reject hierarchy and dominance eat more fruits and vegetables. The results showed that, compared to a control group, individuals in the treatment group who reject hierarchy and dominance (most participants) perceived red and white meat less favourably, decreased their liking of red and white meat, decreased their object identification with red and white meat, anticipated that they would eat more fruits and vegetables in the subsequent three days, and indeed consumed more fruits and vegetables in a follow-up study three weeks later. Moreover, the salience manipulation's ability to induce a negative response toward red and white meat and greater acceptance of fruits and vegetables was strongest for individuals in the treatment group for whom the salience manipulation made sense, individuals with less confidence in their diet choices, those who had previously considered reducing their meat consumption, and low/normal weight persons. These findings have implications for health promotion and for theories of food choice.  相似文献   
42.
Although sarcoidosis has emerged as an important lung disease in this country, clinicians continue to face difficulties in diagnosis and management of the illness. The relative rarity of sarcoidosis and the remarkable similarity of clinical, radiological and histopathological features with tuberculosis pose problems in the differential diagnosis. Although the pattern and sites of involvement do help, the prevalence of tuberculosis, including those of extrapulmonary sites, is so high that a confident exclusion of the illness is not easy. One important point of difference is the presence of tuberculin-anergy in sarcoidosis vis à vis tuberculosis. Bronchoscopic transbronchial lung biopsy is positive in over 80 percent of patients with sarcoidosis. Exclusion of tuberculosis to diagnose sarcoidosis is important in particular because corticosteroids form the mainstay of treatment for sarcoidosis. Asymptomatic patients with stage I pulmonary and other milder forms of cutaneous sarcoidosis do not need systemic steroid therapy. We have found favorable results with steroid sparing drugs such as methotrexate and azathioprine. Patients with refractory disease, relapse of illness and those with steroid induced complications or concomitant illnesses likely to be worsened by corticosteroids, are mostly treated with weekly, low-dose methotrexate.  相似文献   
43.
Emerging evidence suggests that the capacity of a tumor to grow and propagate is dependent on a small subset of cells within a tumor, termed cancer stem cells. In fact, cancer cells, like stem cells, can proliferate indefinitely through a dysregulated cellular self-renewal capacity. Cancer stem cells may originate due to the distribution into self-renewal and differentiation pathways occurring in multi-potential stem cells, tissue-specific stem cells, progenitor cells and cancer cells. Recent studies have shown that ovarian cancer also contains stem cells or tumor-initiating cells. Moreover, ovarian serous adenocarcinomas were disaggregated and subjected to growth conditions to select for self-renewing, non-adherent spheroids previously shown to be derived from tissue stem cells. A recent study showed that epithelial ovarian cancer was derived from a sub population of CD44+, CD117+ and CD133+ cells. The existence of cancer stem cells would explain why only a small minority of cancer cells is capable of extensive proliferation of the tumor. In this review, we have discussed the studies on ovarian cancer stem cells along with the molecular pathways that could be involved in these cancer stem cells.  相似文献   
44.
Basaloid squamous cell carcinoma is a rare variant of squamous cell carcinoma, Larynx has been an uncommon site of this tumour which is said to have aggressive biological behaviour with high incidence of cervical and distant metastasis along with second primary. Two cases of laryngeal basaloid squamous cell carcinoma are reported with relevant review of literature. The submucosal spread of tumour is highlighted alongwith role of preoperative radio therapy.  相似文献   
45.
Metabolic effects of a long-acting low dose injectable contraceptive, norethisterone enanthate 20-mg, monthly injections (Neten-20), was tested in 13 women belonging to the low income groups over a period of 1 year. No change was observed in hemoglobin, hematocrit, glucose tolerance, plasma lipids, iron, calcium, or serum glutamate-oxaloacetate transaminase after treatment. Marginal rise in albumin and fall in some globulin fractions was observed. The slight fall seen in serum alkaline phosphatase could be attributed to a change in lactation status. Vitamin A, pyridoxine and riboflavin status were not altered. A peculiar aberration in the tryptophan-niacin pathway as indicated by rise in kynurenic acid excretion after tryptophan load was observed. This could be corrected by multivitamin therapy. These data suggest that the use of Neten-20 for one year does not lead to adverse metabolic effects analogous to those seen with combination type oral contraceptives.  相似文献   
46.
The effect of dextroamphetamine, primarily a central stimulant, on kinesthetic figural aftereffects (KFAEs) was examined. The subjects were selected after preliminary testing with the Eysenck Personality Inventory and were classified into three groups: extraverts, ambiverts, and introverts. d-Amphetamine was used at three dose levels and a control group was included for purposes of comparison. The 3×4 randomized block design was replicated ten times. KFAEs were measured under two sets of conditions, i.e., before and after the induction experience. The results support the following conclusions: (1) neither personality grouping nor drug treatment during preinduction trials significantly affected KFAE; (2) both types of variables were, however, significantly related to behavior during the postinduction trials; (3) the extraverted subjects showed larger KFAEs than ambiverted and introverted subjects under placebo condition; (4) the extent of KFAE was reduced in extraverted and enhanced in introverted subjects under the influence of the drug; (5) there were significant interactions between the drug treatments and personality variables in effects on KFAE.  相似文献   
47.
Objectives: Experimental models of carcinogenesis show that non-steroidal anti-inflammatory drugs (NSAIDs) increase apoptosis, inhibit angiogenesis and reduce metastases. A linkage between the activity of prostaglandin synthase enzyme cyclooxygenase-2 (COX-2), a known mediator of inflammation, and cancer angiogenesis is implicated. We investigated the expression of COX-2 in bladder cancer tissue specimens using immunohistochemistry. Methods: The immunohistochemical expression of COX-2 in bladder cancer was evaluated by scoring the intensity of immunoreactivity from 0 to 3. Further, the degree of COX-2 expression was correlated with the tumor grade and depth of invasion (T stage). Result: Fifty eight percent patients (n=22) had superficial bladder tumors, while 42% (n=16) were invasive bladder cancers. Overall, COX-2 immuno-positivity was seen in 84.2% (32/38) patients. COX-2 expression was positive in 76.4% (13/17) cases with pTa tumors, 100% (5/5) of pT1 tumors, 86.6% (13/15) of pT2 tumors and in 100% (1/1) of pT3 tumor. The higher stage tumors stained more intensely; this correlation wassignificant(p=0.01987; χ2=19.6977). With reference to the grade of tumors, a positive expression was seen in 81.25% (13/16) of the low-grade tumors and 89% (17/19) of the high-grade tumors. The differential COX-2 expression relative to the grade of tumor was found to be statistically significant (p=0.05; χ2=15.8612). Conclusion: The degree of COX-2 expression is significantly increased with advancing grade and T stage of disease (p < 0.05).  相似文献   
48.
49.
50.
Inflammation may play an important role in the pathophysiology of sickle cell disease (SCD), and recent studies have identified the 70-kDa heat shock protein (Hsp70) as an important mediator of inflammatory responses. Here we demonstrate a significant increase in circulating serum Hsp70 level in SCD during vaso-occlusive crisis (VOC) as compared with baseline steady-state levels (P <0.05) and a significant increase in Hsp70 levels in SCD at baseline compared with normal controls (P <0.05). Taken together, these results indicate that circulating serum Hsp70 might be a marker for VOC in SCD.  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