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   8314篇
  免费   308篇
  国内免费   51篇
耳鼻咽喉   57篇
儿科学   175篇
妇产科学   90篇
基础医学   1166篇
口腔科学   237篇
临床医学   462篇
内科学   1995篇
皮肤病学   171篇
神经病学   633篇
特种医学   367篇
外科学   1470篇
综合类   21篇
一般理论   1篇
预防医学   213篇
眼科学   80篇
药学   563篇
中国医学   15篇
肿瘤学   957篇
  2023年   42篇
  2022年   63篇
  2021年   125篇
  2020年   51篇
  2019年   67篇
  2018年   108篇
  2017年   89篇
  2016年   141篇
  2015年   146篇
  2014年   201篇
  2013年   242篇
  2012年   409篇
  2011年   442篇
  2010年   247篇
  2009年   228篇
  2008年   444篇
  2007年   518篇
  2006年   492篇
  2005年   584篇
  2004年   581篇
  2003年   587篇
  2002年   557篇
  2001年   114篇
  2000年   93篇
  1999年   120篇
  1998年   172篇
  1997年   156篇
  1996年   141篇
  1995年   128篇
  1994年   123篇
  1993年   104篇
  1992年   119篇
  1991年   106篇
  1990年   102篇
  1989年   76篇
  1988年   86篇
  1987年   75篇
  1986年   61篇
  1985年   55篇
  1984年   47篇
  1983年   34篇
  1982年   39篇
  1981年   46篇
  1980年   43篇
  1979年   35篇
  1978年   34篇
  1977年   23篇
  1976年   30篇
  1975年   19篇
  1968年   15篇
排序方式: 共有8673条查询结果,搜索用时 15 毫秒
91.
A 41-year-old man presented with progressive worsening of postural headache. Computed tomography (CT) showed bilateral subdural hematomas without prior history of trauma. The diagnosis was spontaneous intracranial hypotension (SIH). Conservative treatment with oral steroids failed to prevent gradual deterioration of the patient's consciousness. CT myelography revealed massive cerebrospinal fluid (CSF) leakage between the C-1 and C-2 levels. The leak was repaired surgically via a laminectomy. A cyst, thought to be a meningeal cyst, was discovered adjacent to the right C-2 nerve root, and CSF was seen seeping out from around the cyst after a Valsalva maneuver. The presumed dural defect of the cyst was sealed by packing with muscle fragments and fibrin glue. The symptoms disappeared soon after surgery. He was discharged 1 month after surgery without deficits. Most SIH cases are benign and can be managed conservatively, or by the epidural blood patch method. Surgery is more invasive than the epidural blood patch method, but should be performed in patients with a high cervical lesion and massive CSF leakage.  相似文献   
92.
OBJECTIVES: The purpose of this study was to determine the most suitable candidates for scalene lymph node biopsy to detect non-palpable scalene lymph node metastasis (N(3)-scalene) in non-small cell lung cancer patients. METHODS: Standard cervical mediastioscopies and ipsilateral scalene lymph node biopsies were performed preoperatively by a single surgeon on 121 consecutive patients with non-small cell lung cancer scheduled to have surgical resection between January 1997 and August 2002, who had neither evidence of distant metastasis on imaging diagnosis nor palpable supraclavicular lymph nodes. RESULTS: N(3)-scalene was detected in six patients (5.0%), who all had non-squamous cell carcinoma, including one (1.0%) out of 98 patients with negative standard cervical mediastinoscopy and five (21.7%) out of the remaining 23 patients with positive mediastinal lymph node involvement. There was a significant difference in the incidence of the N(3)-scalene between the two groups (P<0.01). Five patients with N(3)-scalene had metastatic lesions in the multilevel mediastinal lymph node station on the same side as the cancer (multilevel N(2)), and accounted for 31.3% of 16 patients with multilevel N(2) disease. The N(3)-scalene was detected in 5 (45.5%) of 11 patients with lung cancer classified as non-squamous cell carcinoma with multilevel N(2) disease. CONCLUSIONS: The results of the present study suggest that non-palpable scalene lymph node biopsy is indicated for lung cancer patients diagnosed as having non-squamous cell carcinoma with mediastinoscopic multilevel N(2) disease.  相似文献   
93.
Interobserver variation in diagnosis of dementia by brain perfusion SPECT   总被引:3,自引:0,他引:3  
Brain perfusion SPECT (BP-SPECT) has characteristic patterns of abnormality, enabling the differential diagnosis of dementia. The purpose of this study was to measure interobserver variations in the diagnosis of dementia using BP-SPECT. BP-SPECT images of 57 cases, 19 of Alzheimer's disease (AD), eight of multi-infarct dementia (MID), three of Pick's disease, five of other dementias, and 22 normal controls, were interpreted by ten nuclear medicine physicians with varying levels of experience. Brain MR images of the cases were then interpreted apart from SPECT. The physicians independently rated all of the diagnoses listed beforehand according to a five-point scale, with clinical information provided. Receiver-operating characteristic (ROC) curves and the area under the ROC curve (Az) were calculated. Az varied from 0.48 to 0.87. Mean Az's were significantly larger (p<0.05) in the diagnosis by SPECT than in that by MRI (0.715 and 0.629 for dementia vs. normal, 0.670 and 0.560 for AD or MID vs. normal, 0.610 and 0.416 for AD vs. normal, and 0.672 and 0.412 for AD vs. MID, respectively). Considerable interobserver variation was present in BP-SPECT interpretation. BP-SPECT may be more effective for the evaluation of dementia than MRI when the same nuclear medicine physicians interpret both images.  相似文献   
94.
95.
A 46-year-old man was presented with a firm mass of the spermatic cord. He underwent left radical orchiectomy with clinical diagnosis of spermatic cord tumor. The pathological examination revealed leiomyosarcoma (3.6 x 2.7 x 1.0 cm, pT1bN0M0; 5th TNM, Stage IA; 5th AJCC). He is free of disease 3 year postoperatively.  相似文献   
96.
A 18-year-old male visited hospital with macroscopic hematuria. Computed tomography showed slightly enhanced left renal tumor that was uncharacteristic for clear cell carcinoma, and radical nephrectomy was performed. Operative specimen revealed primary small cell carcinoma of the kidney. 18 months after operation, bone metastases were diagnosed. Chemotherapy including cisplatinum, etoposide and bleomycin and external irradiation was performed. This intensive therapy was effective for metastatic lesion. He is still alive for 55 months after diagnosis, and is the best controlled case around the world. To our knowledge, this is the 14th case as primary renal small cell carcinoma in the world literature.  相似文献   
97.
Jimbo S  Kobayashi T  Aono K  Atsuta Y  Matsuno T 《Spine》2012,37(20):1763-1770
STUDY DESIGN.: A 12-year prospective study of pre-existing and de novo degenerative lumbar scoliosis (DLS) among community-based female volunteers. OBJECTIVE.: To investigate serial entire spine radiographs of healthy female volunteers and to clarify radiographical characteristics and predictors of pre-existing and de novo DLS. SUMMARY OF BACKGROUND DATA.: DLS is among the most frequent spinal defomities in the aging spine; however, the onset or the natural course of this condition has not been elucidated. METHODS.: A total of 144 female volunteers were recruited from population register. Radiographical measurements using entire spine radiographs included thoracic kyphosis (T4-12), lumbar lordosis (LL) (L1-5), sacral inclination angle, pelvic incidence, sagittal balance (C7 plumb), coronal L4 endplate angle (L4 tilt), and scoliotic angle by Cobb method. More than 10° of scoliosis was diagnosed as DLS. L4 vertebral size was measured (divided by body height) as well as lateral osteophyte formation and lateral disc wedge angle. RESULTS.: Mean baseline age and follow-up period were 54.4 years and 12.1 years, respectively. Pre-existing DLS (pre-DLS) was found in 42 subjects (29.2%) at baseline. Among pre-DLS, 11 subjects (26%) showed more than 5° progression in scoliosis. De novo DLS has developed in 30 subjects (29.4%) among those without baseline scoliosis.Cox proportional hazards models revealed younger age, smaller L4 size, lower LL, greater DLS angle, and L4 tilt at baseline to be the risk factors of progression of pre-DLS and smaller L4 size, unilateral osteophyte formation, and lateral disc wedging to the risk of development of de novo DLS. CONCLUSION.: This study indicated that younger age, smaller L4 size, lower LL, greater DLS angle, and L4 tilt at baseline should be evaluated as predictors of progression of pre-DLS. Early signs of asymmetric disc degeneration and smaller L4 size should also be evaluated as predictors of development of de novo DLS.  相似文献   
98.
Background/PurposeIncreased glycolysis is among the biochemical characteristics of cancerous tissue. The glucose transporter isoform 1 (GLUT1) gene encodes a key factor for glucose transport into cancerous tissue. However, the expression and functional significance of GLUT1 in neuroblastoma have not been fully characterized. Therefore, we investigated the association of GLUT1 expression with clinical outcomes in patients with neuroblastoma using immunohistochemical staining for GLUT1 in neuroblastoma tissues. We also assessed the efficacy of glycolysis inhibition as an anticancer treatment in neuroblastoma cell lines with altered expression of GLUT1.MethodsWe obtained total RNA from cancerous tissue by microdissection in 47 patients with neuroblastoma. GLUT1 expression levels were evaluated by quantitative real-time polymerase chain reaction. We analyzed the association of GLUT1 expression levels with clinical outcomes. We also examined changes in GLUT1 expression and proliferative responses in vitro using 4 neuroblastoma cell lines treated with a glycolysis inhibitor, 3-Bromopyruvate acid.ResultsElevated GLUT1 expression was associated with poor prognosis. Moreover, elevated GLUT1 expression independently predicted overall survival. Immunohistochemical analysis showed that GLUT1 expression tended to be localized to the centers of neuroblastoma cell nests. Our in vitro studies showed that 3-Bromopyruvate acid significantly suppressed the proliferation of neuroblastoma cells with high GLUT1 gene expression compared with those with low expression.ConclusionGlycolysis inhibitors are a potential therapeutic option for treating aggressive tumors expressing GLUT1.  相似文献   
99.
100.
Yoshimura J  Onda K  Tanaka R  Takahashi H 《Neurologia medico-chirurgica》2003,43(8):375-82; discussion 382
Diffuse type brainstem glioma is one of the most malignant types of brain tumors and the prognosis is extremely poor. The proliferative potential of these tumors is presumed to be very high, but there is little information about the cell kinetics of brainstem glioma because surgical resection is rarely performed. The histological grade, tumor spread, growth potential, and prognosis were evaluated in 40 autopsy cases of diffuse type brainstem glioma. To quantify the growth potentials of individual tumors, the proliferating cell indices of Ki-67 (MIB-1) and proliferating cell nuclear antigen (PCNA) monoclonal antibodies were measured. Mean MIB-1 and PCNA proliferating cell indices were 20.4% (24 cases) and 37.0% (28 cases), respectively, in 34 glioblastomas. The median survival time was 40 weeks in 22 treated patients. The mean PCNA proliferating cell index was 10.8% in four of five anaplastic astrocytomas and the median survival time in four treated patients was 91 weeks. The MIB-1 and PCNA proliferating cell indices of one astrocytoma were 2.9% and 20.3%, respectively, and the survival time was 56 weeks. The overall median survival time was 32 weeks. There was a significant difference in PCNA proliferating cell indices between glioblastomas and anaplastic astrocytomas (p < 0.05) and there was a significant difference in survival time between glioblastomas (40 weeks) and anaplastic astrocytomas plus astrocytoma (74 weeks) among the treated patients (p < 0.05). Supratentorial extension was more frequent in glioblastomas than in anaplastic astrocytomas (p < 0.05). Our results suggest that the majority of diffuse type brainstem gliomas are glioblastoma and the proliferative potential is probably as high as that of adult supratentorial glioblastoma. Supratentorial extension and dissemination are relatively frequent in the advanced stage. Anaplastic astrocytoma or astrocytoma is rarer and less infiltrative and proliferative, and carries a slightly better prognosis than glioblastoma.  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