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   46104篇
  免费   3010篇
  国内免费   929篇
耳鼻咽喉   358篇
儿科学   1173篇
妇产科学   1214篇
基础医学   5126篇
口腔科学   809篇
临床医学   3984篇
内科学   10939篇
皮肤病学   709篇
神经病学   4187篇
特种医学   1722篇
外国民族医学   2篇
外科学   6189篇
综合类   2086篇
现状与发展   1篇
一般理论   2篇
预防医学   2412篇
眼科学   582篇
药学   3951篇
  8篇
中国医学   964篇
肿瘤学   3625篇
  2023年   405篇
  2022年   1055篇
  2021年   1619篇
  2020年   1027篇
  2019年   1113篇
  2018年   1243篇
  2017年   1023篇
  2016年   1070篇
  2015年   1364篇
  2014年   1781篇
  2013年   2194篇
  2012年   2853篇
  2011年   2893篇
  2010年   1742篇
  2009年   1608篇
  2008年   2449篇
  2007年   2497篇
  2006年   2287篇
  2005年   2167篇
  2004年   1977篇
  2003年   1712篇
  2002年   1541篇
  2001年   1426篇
  2000年   1349篇
  1999年   1259篇
  1998年   451篇
  1997年   337篇
  1996年   362篇
  1995年   280篇
  1994年   258篇
  1993年   220篇
  1992年   689篇
  1991年   577篇
  1990年   548篇
  1989年   559篇
  1988年   470篇
  1987年   425篇
  1986年   407篇
  1985年   320篇
  1984年   267篇
  1983年   214篇
  1982年   119篇
  1979年   215篇
  1978年   131篇
  1977年   114篇
  1974年   124篇
  1973年   130篇
  1972年   124篇
  1971年   110篇
  1969年   102篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Di Benedetto  P.  Giorgini  T.  Delneri  C.  Biasutti  E. 《Neurological sciences》2006,27(4):s320-s322
Neurological Sciences - Bladder and urethra are innervated peripherally by pelvic parasympathetic, lumbar sympathetic and pudendal nerves; but a complex of brain networks is involved in the...  相似文献   
42.
Cancer cells elaborate metalloproteinases which may play a role in invasion and metastasis. The serum level of the M(r) 72,000 type IV collagenase (MMP-2) was measured in 87 lung cancer patients. Stage IV cancer levels were significantly elevated (P less than 0.0001) compared to normal sera. A significant difference (P less than 0.01) was found between enzyme levels in the presence versus the absence of distant metastasis. For 29 patients treated with combination chemotherapy, a positive relationship was noted between response failure and elevated enzyme levels. Serum metalloproteinase levels may provide information relevant to prognosis as well as treatment decisions.  相似文献   
43.
BACKGROUND: Coronary vasculopathy is the main cause of cardiac graft failure. Because yearly coronary angiography is invasive in children, a non-invasive method for detecting graft vasculopathy is needed. The aim of this study was to test dobutamine-stress echocardiography in a pediatric population to determine its feasibility, safety and reliability in the detection of graft coronary artery disease. METHODS: Eighteen patients, aged 2 days to 16.8 years at transplantation (mean 8.4 years), underwent 44 dobutamine-stress echocardiography (DSE) exams, at a follow-up of 1.1 to 11.8 years (mean 5.1 years). Selective coronary angiography was performed for comparison. Echocardiographic recordings were obtained in 4 standard views of the left ventricle and measurements carried out within the frames of a 16-segment model. Segmental scores of contractility were obtained for each segment and a total segmental contractility index was calculated at each stage. RESULTS: All patients reached the maximum dose stage. Maximum heart rate was 57% to 90% of predicted maximum. Maximum systolic blood pressure reached 190 mmHg. Segmental scores were normal in 37 and abnormal in 7 cases. Echographic results were concordant with angiography in 82% and discordant in 18% of the cases (4 negative DSEs with minor angiographic lesions, 2 positive DSEs with normal angiography), but there was no significant angiographic lesion with normal DSE. CONCLUSIONS: DSE is a safe and highly feasible non-invasive technique in transplanted children. A normal DSE study successfully predicts the absence of significant coronary artery disease in the post-transplant population.  相似文献   
44.
A series of 1153 fine-needle aspiration biopsies (FNAB) of breast masses obtained during the period 1985 to 1988 in one institution was examined. The following diagnostic accuracy values were found: sensitivity, 93.0%; specificity, 92.4%; predictive positive value, 93.7%; and efficiency, 92.8%. These results were compared with a previously published series for the period 1976 to 1984. The diagnostic accuracy values did not differ significantly between the two series.  相似文献   
45.
Repetitive conservative surgery for recurrence of endometriosis   总被引:4,自引:0,他引:4  
We evaluated the recovery of fertility and the relief of pain symptoms in a long-term follow-up of 42 women undergoing repetitive conservative surgery for recurrent endometriosis. The mean age of the patients was 31.1 +/- 4.3 years. At the time of their second operation the disease was stage IV in 14 women, stage III in 25, and stage I in three. After reoperation, the patients were followed for a mean period of 41.8 +/- 30.3 months. Pain symptoms returned in eight women, dysmenorrhea and deep dyspareunia in eight, and pelvic pain in seven. Eight of the 28 women (28.6%) who attempted to conceive achieved a total of 13 pregnancies. The corrected pregnancy rate was 35%, and the cumulative rate at 27 months was 30.7%. A third operation was necessary in six women after a mean period of 35 months. Conservative surgery is an effective therapeutic option for infertile patients with recurrent endometriosis.  相似文献   
46.
47.
Central sensory and motor conduction in vitamin B12 deficiency.   总被引:7,自引:0,他引:7  
Four patients with subacute combined degeneration were studied through upper and lower limb SEPs recorded with a non-cephalic reference montage and through cortical and spinal magnetic stimulation. Clinical signs were confined to the lower limbs in 3 patients; the remaining patient presented only paraesthesiae in 4 limbs. Median nerve SEPs showed a normal cervical N13 response with a significant increase of central conduction time concerning exclusively the P9-P14 interpeak interval. Central motor conduction to upper and lower limb muscles was abnormal. Nerve conduction studies provided no evidence of peripheral nerve involvement. These electrophysiological findings suggest that in vitamin B12 deficiency the higher segments of the cervical cord are usually affected first and that central sensory and motor conduction studies are sensitive methods for detecting such damage.  相似文献   
48.
白细胞介素—2新的功能位点及其中枢镇痛作用   总被引:2,自引:0,他引:2  
白细胞介素-2(IL-2)不仅是重要的免疫调节因子,而且还具有重要的中枢调节作用。本实验以钾离子透入引起大鼠甩尾反应为指标,发现侧脑室注射IL—2能显著提高动物痛阈,并能被纳洛酮所阻断,表示IL-2的中枢镇痛作用可能与阿片受体有关。利用基因定位突变技术获得的无免疫活性IL-2实查体仍具有中枢镇痛作用,表明IL—2分子上发挥镇痛和免疫调节作用的功能位点是相互独立的。纳洛酮能够阻断IL—2的中枢镇痛作用,而不能影响IL—2增殖CTLL-2细胞的作用,提示IL-2发挥镇痛和免疫调节作用可能通过不同的受体途径。IL-2分子中第45位Tyr残基突变为Val后,虽仍保留了免疫活性,但丧失了镇痛功能,表示45位Tyr残基是IL—2发挥中枢镇痛功能的关键残基之一。我们推测IL—2的镇痛功能位点可能在IL—2分子中第45位Tyr残基附近区域。  相似文献   
49.
The Marlowe-Crowne Social Desirability Scale, a 33-item self-report questionnaire, was administered to an age-matched sample of twenty-five irritable bowel syndrome (IBS) patients, twenty-four psychiatric patients meeting a diagnosis of major depression, and nineteen controls. As predicted, planned comparisons analysis showed a significant group effect: IBS group scores were significantly higher than both depressed and control group scores (p less than .05). Implications of this social desirability response set for the psychological assessment and treatment of IBS are discussed.  相似文献   
50.
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