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   13336篇
  免费   633篇
  国内免费   121篇
耳鼻咽喉   76篇
儿科学   304篇
妇产科学   209篇
基础医学   1623篇
口腔科学   199篇
临床医学   754篇
内科学   3590篇
皮肤病学   467篇
神经病学   955篇
特种医学   790篇
外科学   2527篇
综合类   67篇
一般理论   2篇
预防医学   260篇
眼科学   179篇
药学   673篇
中国医学   23篇
肿瘤学   1392篇
  2023年   60篇
  2022年   106篇
  2021年   263篇
  2020年   177篇
  2019年   191篇
  2018年   254篇
  2017年   236篇
  2016年   308篇
  2015年   318篇
  2014年   442篇
  2013年   513篇
  2012年   713篇
  2011年   851篇
  2010年   549篇
  2009年   478篇
  2008年   818篇
  2007年   855篇
  2006年   874篇
  2005年   888篇
  2004年   807篇
  2003年   771篇
  2002年   845篇
  2001年   166篇
  2000年   156篇
  1999年   197篇
  1998年   240篇
  1997年   186篇
  1996年   198篇
  1995年   167篇
  1994年   132篇
  1993年   123篇
  1992年   135篇
  1991年   122篇
  1990年   119篇
  1989年   82篇
  1988年   73篇
  1987年   68篇
  1986年   54篇
  1985年   42篇
  1984年   55篇
  1983年   34篇
  1982年   39篇
  1981年   41篇
  1980年   40篇
  1979年   33篇
  1978年   22篇
  1977年   23篇
  1971年   21篇
  1970年   19篇
  1967年   31篇
排序方式: 共有10000条查询结果,搜索用时 672 毫秒
31.
32.
Summary: Clinical studies revealed that angiotensin converting enzyme (ACE) inhibitor reduces proteinuria and attenuates progressive decline in renal function in IgA nephropathy. Recent studies by us and others have demonstrated that the homozygote of the D allele (DD) of the ACE insertion/deletion (I/D) polymorphism is a potential risk factor for poor prognosis in IgA nephropathy, and that this deletion polymorphism predicts the therapeutic efficacy of ACE inhibition on proteinuria and, potentially, on progressive deterioration of renal function in patients with the nephropathy.  相似文献   
33.
Background :
In an attempt to determine the biological significance of nuclear morphometric findings, measurements of mean nuclear volume (MNV) and nuclear roundness factor (NRF) were compared to the immunoreactivityof p53 expression and proliferating cell nuclear antigen (PCNA) in human bladder cancer.
Methods :
MNV and NRF were measured using stereological methods. Expression of p53 and PCNA were determined by immunohistochemical staining. Specimens from 111 patients with previously untreated bladder cancer were analyzed.
Results :
The mean MNV was 235.8 ± 1 33.6 μm3 for the 81 patients with p53-labeling index (LI) less than 10% and 337.2 ± 141.0 μn3 for the 30 patients with p53 LI greater than 10% (P = 0.008). There was Resign if icant correlation between NRF and expression of p53. The mean MNV was 220.1 ± 1 20.5 μm3 for the 67 patients with PCNA LI less than 28% (the mean value of PCNA LI) and 328.9 ± 149.2 μm3 in 44 patients with PCNA LI greater than 28% (P= 0.0001). The mean NRF was 80.7 ± 4.2 for the 67 patients with PCNA LI less than 28%, and 82.3 ± 3.4 for the 44 patients with PCNA LI more than 28% (P= 0.04). Conclusion: Nuclear morphometric findings may reflect the proliferative potential of cancer eel Is of the bladder, as indicated by findings of immunostaining for p53 and PCNA.  相似文献   
34.
Objective. Tympanic temperature can be obtained instantaneously using an infrared emission detection (IRED) thermometer. Its accuracy has been documented in a variety of clinical settings, but its performance at low body temperatures is still unknown. In this study we evaluated its performance during coronary artery revascularization surgery in which mild hypothermic cardiopulmonary bypass (CPB) was used. Methods. Thirty adult patients undergoing coronary artery bypass graft surgery were enrolled in the study. Tympanic temperature obtained using IRED thermometry (Tt1) was compared with core temperatures from the esophagus (Te), and venous blood of CPB (Tv) before, during, and after CPB. We also measured tympanic temperature using a thermocouple probe (Tt2) in 16 of the 30 patients in order to study the agreement between the two methods. Values for correlation coefficients and limits of agreement were computed to assess the degree of agreement among the temperatures obtained. Results. The highest agreement with Tv during CPB was obtained from Tt1 (r = 0.94, 0.41 ± 1.73, limits of agreement) and from Te (0.91, 0.36 ± 2.46). Tt1 also showed good agreement with Tt2 during surgery. Conclusions. Infrared tympanic thermometry is a reliable, alternative method to measure tympanic temperature and may be useful to assess core temperature in both normothermic and mild hypothermic conditions.  相似文献   
35.
1. The effects of acute bilateral superior cervical ganglionectomy on cerebral blood flow and metabolism were investigated in stroke-prone spontaneously hypertensive rats (SHRsp), before and during cerebral ischaemia. 2. The resting cerebral blood flow was comparable between the control and denervated animals. 3. There was no significant difference in cerebral blood flow or concentration of tissue energy metabolites (adenosine triphosphate [ATP], lactate and pyruvate) between the sham-operated control and denervated animals during ischaemia. 4. The results suggest that sympathetic innervation of cerebral vessels originating from superior cervical ganglia may not play a major role in the progression of cerebral ischaemia in SHRsp.  相似文献   
36.
The purpose of this study was to determine the relationship between segmental hyperintensity of the liver on T1-weighted images and segmental cholestasis in patients with obstructive jaundice. T1-weighted and T2-weighted MR images were obtained of 73 patients with obstructive jaundice caused by various diseases. Fat-suppressed T1-weighted images were also obtained of 10 patients. Eleven patients with segmental intra-hepatic bile duct dilatation (cholestasis) showed segmental hyperintensity on T1-weighted images and/or fat-suppressed T1-weighted images and no signal intensity difference on T2-weighted images. Sixty-two patients with widespread intrahepatic bile duct dilatation showed no intensity difference on T1-weighted and T2-weighted images (P < .01). Segmental hyperintensity on T1-weighted images was correlated with intrahepatic cholestasis.  相似文献   
37.
In order to study the mechanism of GH secretion from somatotroph adenoma cells, we have compared the effect of 12–O-tetradecanoyl phorboi-13-acetate (TPA) with that of growth hormone releasing factor (GRF) on GH secretion from human somatotroph adenoma cells cultured in monolayer. Pituitary adenoma cells were obtained from 13 patients with acromegaly undergoing surgery. On the 7th day of culture, the cells were exposed for 2 h to secretagogues. All 13 adenoma cell cultures (100%) responded to TPA (1·6–16·0 nmol/I) with a two- to six-fold increase in GH release (240·37% Increase of control: mean±SE). The response was detectable within 10 min, and was maximal at 2 h. Phosphollpase C (7·7 mmol/I) also stimulated a two-to ten-fold Increase In GH release in all four adenomas examined (100%). GH release was stimulated by GRF (2·0 nmol/I) in eight out of 12 adenoma cells (67%), but the magnitude of the responses to GRF (60·18% Increase of control: mean ± SE) were much smaller than that of TPA. Five out of 13 adenomas secreted detectable amount of PRL Into the medium and these five adenomas (100%) responded to TPA (16·0 nmol/I) with a two- to six-fold Increase. These observations indicate that the activation of protein kinase C is the consistent stimulator in GH and PRL secretion In human somatotroph adenoma cells. However, It is not determined whether the protein kinase C  相似文献   
38.
Between 1969 and 1995, 180 patients underwent complete resection of lung metastases during initial thoracotomy at our institute, involving the resection of 917 pulmonary nodules at 202 thoracotomy procedures. The overall postmetastasectomy 5- and 10-year survival rates were 46% and 30%, respectively. Of 111 patients who underwent segmentectomy and/or local excision, 57 had multiple metastases, 39 of whom were treated by Nd:YAG laser after 1986, and 18 by conventional procedures before 1985. The average number of tumors resected per patient treated with the Nd:YAG laser was significantly greater than that of those treated with conventional procedures. However, the survival curve of the laser-treated group was better than that of the laser-nontreated group. Moreover, slightly better survival was achieved in patients operated on after 1992 compared with those operated on before 1991. We conclude that the laser technique may be warranted to afford complete resection of metastases and adequate pulmonary reservation in combination with a selected approach for thoracotomy under the exact detection of tumor localization using the most recent high-quality computed tomography (CT) scan. Furthermore, a one-stage operation to control synchronous intra- and extrapulmonary malignamcies may become a possible option in combination with selective adjunctive therapy.  相似文献   
39.
Postoperative pain relief with epidural morphine or buprenorphine and intramuscular morphine was investigated in 67 patients undergoing hepatectomy. When the patient first complained of pain after surgery, 1 or 2mg of epidural morphine, or 0.06 mg of epidural buprenorphine given either at T 10-11 or L 3-4, or 0.1 mg/kg of morphine intramuscularly was administered. Lumbar epidural morphine 2mg, as well as thoracic epidural morphine 2mg, produced excellent and long-lasting pain relief. Nine of 12 patients receiving thoracic epidural buprenorphine 0.06 mg were completely pain-free. Thoracic epidural morphine 1 mg and lumbar epidural buprenorphine 0.06 mg produced incomplete analgesia. Analgesic duration of intramuscular morphine tended to be shorter than that of 2 mg of epidural morphine. PaCO2 increased significantly following thoracic epidural morphine 2 mg, although PaCO2 did not change after lumbar epidural morphine 2 mg. No patient had serious side effects. The lumbar epidural administration of 2 mg morphine may be recommended for postoperative analgesia following hepatectomy.  相似文献   
40.
We report on a family with ataxia type 6 (SCA6) showing peculiar oculomotor symptoms. The proband presented with periodic alternating nystagmus (PAN), and her 2 brothers had rebound nystagmus and gaze-evoked nystagmus. They carried the identical mutation (the number of expanded CAG repeat, 24) in the CACNA1A gene. The intrafamilial variability of oculomotor symptoms may be ascribed to factors other than CAG repeat expansion size in SCA6.  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