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   69275篇
  免费   3194篇
  国内免费   404篇
耳鼻咽喉   837篇
儿科学   1877篇
妇产科学   1701篇
基础医学   8221篇
口腔科学   2186篇
临床医学   4970篇
内科学   18976篇
皮肤病学   1727篇
神经病学   6033篇
特种医学   1907篇
外科学   10371篇
综合类   278篇
一般理论   11篇
预防医学   4594篇
眼科学   1165篇
药学   3696篇
中国医学   206篇
肿瘤学   4117篇
  2023年   453篇
  2022年   846篇
  2021年   1960篇
  2020年   985篇
  2019年   1663篇
  2018年   2491篇
  2017年   1508篇
  2016年   1579篇
  2015年   1770篇
  2014年   2324篇
  2013年   3238篇
  2012年   5142篇
  2011年   5250篇
  2010年   2900篇
  2009年   2426篇
  2008年   4468篇
  2007年   4662篇
  2006年   4413篇
  2005年   4396篇
  2004年   3994篇
  2003年   3582篇
  2002年   3330篇
  2001年   1283篇
  2000年   1429篇
  1999年   1168篇
  1998年   500篇
  1997年   391篇
  1996年   368篇
  1995年   328篇
  1994年   263篇
  1993年   204篇
  1992年   455篇
  1991年   338篇
  1990年   348篇
  1989年   253篇
  1988年   191篇
  1987年   179篇
  1986年   197篇
  1985年   167篇
  1984年   142篇
  1983年   115篇
  1982年   115篇
  1981年   82篇
  1980年   83篇
  1979年   71篇
  1978年   63篇
  1977年   61篇
  1976年   62篇
  1974年   78篇
  1973年   77篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
A neonate vaccinated against HBV was the source of an occupational exposure to blood. She was tested for hepatitis B surface antigen and found to be positive, leading to unnecessary treatment, retesting, and concern. Evaluation of the infectious status of HBV should rely on other means if vaccination has recently occurred.  相似文献   
32.
Summary Genes involved in cancer generation are usually tumor suppressors and oncogenes. Progressive genetic alterations in these genes are involved in the mechanisms of tumorigenesis. In prostate cancer, additionally several chromosomal loci that should harbor mutated genes have been proposed. Some genes have been found altered in prostate cancer, such as PTEN, TP53, AR, RNASEL (HPC1), ELAC2 (HPC2), CDKN2A and MSR1 and those can be natural targets for new strategies of treatment. Besides, gene therapy has been suggested to be suitable for prostate cancer treatment. This approach includesex vivo corrective therapy, suicide, and antisense therapy.  相似文献   
33.
34.
35.
We investigated the expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-3 (LFA-3) by thyrocytes and their regulation by cytokines. Immunofluorescence studies on cryostat sections and on freshly dispersed cell preparations showed that ICAM-1 and LFA-3 are barely detectable in non-autoimmune thyrocytes. However, thyrocytes acquired ICAM-1 expression in culture. IFN-gamma, IL-1 beta and TNF-alpha produced a clear enhancement of ICAM-1 expression. When tested in combination, IL-1 beta and TNF-alpha were additive to the IFN-gamma effect. LFA-3 expression was not modulated by these cytokines. In the HT93 thyroid cell line generated by transfection with SV40, ICAM-1 and LFA-3 were both constitutively expressed at high levels. Cytokines modulated ICAM-1 expression similarly, but to a greater extent than in normal thyrocytes. LFA-3 remained unmodified. These results support the notion that normal thyrocytes are immunologically silent cells. The capability of cytokines to induce ICAM-1 together with HLA class I and class II-expression on thyrocytes suggests that under their influence, these cells may express all the surface molecules required for antigen presentation and/or for being recognized as target cells in the context of thyroid autoimmune disease.  相似文献   
36.
37.
Hyperexcitability of the motor system has been reported in Parkinson's disease (PD). We evaluate how cutaneous afferents modulate motor excitability in PD patients and whether abnormal modulation is correlated to parkinsonian symptoms. Digital stimulation causes abnormal enhancement of motor responses in patients. This effect may be one of the features of motor hyperexcitability in PD. Cutaneomotor hyperexcitability correlates with clinical scores, suggesting that abnormal processing of cutaneous inputs might contribute to the pathogenesis of parkinsonian symptoms.  相似文献   
38.
Captopril is a suitable drug to treat high blood pressure in diabetic patients. This Angiotensin-Converting Enzyme Inhibitor (ACEI) is a vasodilator without tachycardia and saline retention. Furthermore, captopril is one of antihypertensive drugs with less adverse effects. It does not induce metabolic changes, improves glucose tolerance and brake the evolution of renal insufficiency. About 50-60% of patients are under control (DBP < 90 mmHg) with captopril monotherapy. In the present paper, were included 64 women and 16 men with diabetes mellitus and mild-moderate hypertension, I-II phase WHO. The average age (mean +/- S.D.) was 66.6 +/- 9.2 years. All patients were treated with 25 mg/12 h of captopril, for one month. If blood pressure was not under control, captopril treatment enhanced to 50 mg/12 h during second month. After this period of two months, patients under control were got out of this study. 37 patients (46.25%) needed a second drug. In randomized form, 20 patients associated 25 mg HCTZ one time a day (CAP + HCTZ); and 17 patients associated 20 mg/12 h of nifedipine retard (CAP + NIF). The study continued for 4 months more. Both treatments reduced blood pressure in significant form without changes statistical significant in the heart rate, weight, glycemia, cholesterol, triglycerides, c-HDL, uric acid, creatinine, Na+ and K+ blood levels. CAP + HCTZ controlled (DBP < 90 mHg) 85% and CAP + NIF 81.25% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
39.
Reports of the human teratogenicity of retinoids have raised concern about the potential human teratogenicity of high doses of vitamin A. Nevertheless, there are few human case reports of excess intake of vitamin A during pregnancy and defective outcomes. No epidemiological studies have been carried out on this subject. Here we present the results of an epidemiological study of prenatal exposure to high doses of vitamin A in Spain, using data from the Spanish hospital-based, case-control registry. Although it is difficult to reach conclusions with such a very low exposure level (1.3 per 1,000 livebirths), our results suggest that a teratogenic effect might exist for exposures to high doses of vitamin A (OR = 0.5, p = 0.15 for less than 40,000 FU and OR = 2.7, p = 0.06 for 40,000 1U or more). As we might expect, this effect also seems to be related to the organogenetic status (OR = 5.4, p = 0.1 for 1st –2nd month, OR = 1.8, p = 0.4 for 3rd onwards) at the time of exposure.  相似文献   
40.
Two cases are presented in which conventional approaches did not permit dilation of and stent placement in obstructed ureters. In patients with iatrogenic ureteral laceration or rigid ureteral kinking, direct percutaneous translumbar puncture may provide a safe alternative. The authors' technique is described.  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