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   8814篇
  免费   446篇
  国内免费   44篇
耳鼻咽喉   70篇
儿科学   104篇
妇产科学   56篇
基础医学   950篇
口腔科学   329篇
临床医学   553篇
内科学   2247篇
皮肤病学   248篇
神经病学   628篇
特种医学   342篇
外科学   1437篇
综合类   24篇
预防医学   292篇
眼科学   143篇
药学   846篇
中国医学   11篇
肿瘤学   1024篇
  2023年   41篇
  2022年   56篇
  2021年   182篇
  2020年   87篇
  2019年   135篇
  2018年   189篇
  2017年   135篇
  2016年   155篇
  2015年   141篇
  2014年   206篇
  2013年   277篇
  2012年   398篇
  2011年   430篇
  2010年   244篇
  2009年   215篇
  2008年   371篇
  2007年   437篇
  2006年   451篇
  2005年   443篇
  2004年   422篇
  2003年   427篇
  2002年   414篇
  2001年   295篇
  2000年   339篇
  1999年   288篇
  1998年   95篇
  1997年   90篇
  1996年   80篇
  1995年   66篇
  1994年   63篇
  1993年   56篇
  1992年   191篇
  1991年   162篇
  1990年   167篇
  1989年   173篇
  1988年   155篇
  1987年   148篇
  1986年   130篇
  1985年   128篇
  1984年   101篇
  1983年   76篇
  1981年   36篇
  1979年   57篇
  1978年   43篇
  1977年   42篇
  1973年   49篇
  1972年   41篇
  1971年   42篇
  1969年   48篇
  1968年   51篇
排序方式: 共有9304条查询结果,搜索用时 15 毫秒
51.
In vivo administration of chloroquine to rats caused an increase in the pH of hepatocyte lysosomes within 1 hr after administration with a return to baseline pH values by 3 hr; continued administration of chloroquine for up to 12 days was unaccompanied by any further changes in hepatocyte lysosomal pH. We interpret these data as evidence against a major role for an increase in the pH of hepatocyte lysosomes in CAC-induced phospholipidosis.  相似文献   
52.
A 58-year-old woman was admitted due to an abnormal shadow on chest X-ray, without any symptoms. Chest computed tomography showed a round mass in the anterior segment of the right upper lobe. Segmentectomy was performed and histopathological examination revealed a primary neurogenic tumor of Schwann cell origin. Immunohistochemical staining demonstrated the presence of S-100 protein in the tumor cells. We present a case of intrapulmonary schwannoma and review 62 cases of primary schwannoma of the lung.  相似文献   
53.
PURPOSE: To evaluate the treatment results of low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy (ISBT) for T3 mobile tongue cancer. MATERIAL AND METHODS: Between 1974 and 1992, 61 patients with T3 mobile tongue cancer were treated with LDR ISBT using (192)Ir hairpins with or without single pins. In addition, between 1991 and 1999, 14 patients were treated with HDR ISBT. For nine patients treated with ISBT alone, the total dose was 59-94 Gy (median 72 Gy) within one week in LDR ISBT and 60 Gy/10 fractions/5 days in HDR ISBT. For 66 patients treated with a combination therapy of external beam radiotherapy (EBRT) and ISBT, the total dose was 12.5-60 Gy (median 30 Gy) of EBRT and 50-112 Gy (median 68 Gy) within 1 week in LDR ISBT or 32-60 Gy (median 48 Gy)/8-10 fractions/5-7 days in HDR ISBT. RESULTS: The 2- and 3-year local control rates of all patients were both 68%. The 2- and 3-year local control rates of patients treated with LDR ISBT were both 67%, and those with HDR ISBT were both 71%. The local control rate of patients treated with HDR ISBT was similar to those with LDR ISBT. CONCLUSIONS: ISBT for T3 mobile tongue cancer is effective and acceptable. The treatment result of HDR ISBT is almost similar to that of LDR ISBT for T3 mobile tongue cancer.  相似文献   
54.
We previously reported the hyperosmolarity response (a decrease of the ocular standing potential by hyperosmolarity) as a new clinical test of the retinal pigment epithelium (RPE) activity. In the present study a hypertonic solution (Fructmanit, 1.4 × 103 m0sm/1) was intravenously injected for 20 min in proportion to a subject's total blood volume (TBV). At the injection speed of 5, 10, and 15% of the subjects' TBV per hour the mean amplitude of the hyperosmolarity response in normal subjects was 19.7, 30.1 and 36.4% respectively. The amplitude of the hyperosmolarity response depends on the logarithm of the dose of the hypertonic solution within the range of the dose tested.We previously found that hyperosmolarity suppresses the light rise. The present study investigated this suppressive effect in a quantitative manner. The light rise (a full-field illumination of 1.2 × 103 cdl/m2) was dose-dependently suppressed by Fructmanit. The mean of the light rise to dark trough ratio in normal subjects was 1.81 with no osmotic stress, and 1.64, 1.41 and 1.29 respectively at the injection speeds of 5, 10, and 15%. The suppression of the light rise by hyperosmolarity is compatible with the view that the hyperosmolarity response and the light rise share the basal membrane of the RPE as the main site of their generation.  相似文献   
55.
A 51-year-old woman, with progressive gait disturbance and dysarthria, had been diagnosed as Menzel-type spinocerebellar degeneration. Later, she developed dystonic posture of upper limbs and bulging eyes. She was diagnosed as Machado-Joseph disease from neurological findings, which consisted of cerebellar signs, pyramidal tract signs and extrapyramidal tract signs and peripheral neuropathy. She died suddenly of unknown origin. Her illness lasted about 13 years. Neuropathological findings showed moderate neuronal loss with gliosis in the subthalamic nucleus, globus pallidus, substantia nigra, dentate nucleus, oculomotor and hypoglossal nucleus and anterior horn. Positron emission tomography (PET) using 15O steady state inhalation technique revealed reduction of cerebral blood flow and cerebral metabolic rate of oxygen in not only cerebellum but also cerebral cortex. These findings are different from typical PET findings of spinocerebellar degeneration.  相似文献   
56.
57.
This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8–14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n=6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extracellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n=4) and those rats without tonsillar herniation (n=4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.  相似文献   
58.
Recent progress in molecular biology suggests a certain relationship between penile cancer and human papilloma virus infection. However, the treatment for penile cancer has not been established since each institute has experienced only a small number of patients. We analyzed the result of our treatment for 14 penile cancer patients during past twenty years. Ten of the 14 patients were initially treated for the primary lesion with a combination of peplomycin (PEP) or bleomycin (BLM) and radiation therapy. Of these, 9 were found not to have residual viable cancer cells in their primary lesions. No local recurrence was found in all 7 patients in whom the penis was preserved. This result suggests that combination of PEP (BLM) and radiation preserves the penis without increasing the risk of local recurrence. Penile cancer-related death did not occur in patients without lymph node metastasis. However, this cancer death did occur in 4 out of 7 patients with lymph node metastasis, suggesting that metastasis is one of the important prognostic factors. PEP (BLM) and radiation therapy with or without regional lymph node dissection did not improve the prognosis of patients with advanced penile carcinoma, such as with pN2, pN3 or distant metastasis. More effective management may be necessary for these patients.  相似文献   
59.
60.
We studied the long-term outcome of 268 patients suffering fromdiabetic end-stage renal disease (DM-ESRD) treated with long-termhaemodialysis between 1978 and 1991, with special emphasis onvisual acuity as well as the heterogeneity of DM-ESRD The 50%patient survival on haemodialysis was 60 months. Visual disturbanceswere found in 73.1% (392/536) of eyes at the start of haemodialysis.Chronological assess ment of visual acuity demonstrated thestabilization of visual acuity and 87.1% (364/418) of eyes werestable, 4.8% (20/418) were improved, and 8.1% (34/418) wereaggravated in the long term respectively. The change of visualacuity was frequently seen in the short term, and rapid shiftsof body fluid to correct overhydration induced abrupt changesof glycaemic control as well as retraction of macular oedema.Hence it might be one of the factors affecting rapid changeof visual acuity in the short term. Meanwhile, long-term deterioration of visual acuity resulted from either hyperten sionunresponsive to medical treatment or poor glycaemic control.Some DM-ESRD patients had only background retinopathy at thestart of haemodialysis and these were likely to have the nephroscleroticglomerular lesion. They were old, not nephrotic and had a milddegree of diabetes during the predialysis stage. Thus, DM-ESRDpatients seem to have some heterogeneity in their clinical characteristics,and old DM-ESRD patients with only background retinopathy havethe appearance of diabetic macroangiopathy rather than microangiopathy.  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