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   4173篇
  免费   289篇
  国内免费   16篇
耳鼻咽喉   25篇
儿科学   179篇
妇产科学   115篇
基础医学   610篇
口腔科学   58篇
临床医学   359篇
内科学   900篇
皮肤病学   88篇
神经病学   515篇
特种医学   126篇
外科学   529篇
综合类   14篇
一般理论   2篇
预防医学   269篇
眼科学   39篇
药学   304篇
中国医学   6篇
肿瘤学   340篇
  2024年   5篇
  2023年   44篇
  2022年   96篇
  2021年   170篇
  2020年   114篇
  2019年   162篇
  2018年   176篇
  2017年   137篇
  2016年   149篇
  2015年   149篇
  2014年   216篇
  2013年   239篇
  2012年   351篇
  2011年   343篇
  2010年   195篇
  2009年   157篇
  2008年   287篇
  2007年   237篇
  2006年   208篇
  2005年   207篇
  2004年   167篇
  2003年   139篇
  2002年   101篇
  2001年   29篇
  2000年   32篇
  1999年   29篇
  1998年   20篇
  1997年   21篇
  1996年   21篇
  1995年   10篇
  1994年   6篇
  1993年   15篇
  1992年   23篇
  1991年   15篇
  1990年   17篇
  1988年   21篇
  1987年   21篇
  1986年   21篇
  1985年   14篇
  1984年   18篇
  1983年   7篇
  1982年   5篇
  1980年   6篇
  1979年   6篇
  1978年   8篇
  1977年   6篇
  1974年   5篇
  1972年   12篇
  1970年   5篇
  1967年   6篇
排序方式: 共有4478条查询结果,搜索用时 31 毫秒
41.
Summary To extend initial results on the antineoplastic activity of -1,3,5-triglycidyl-s-triazinetrione (TGT, NSC 296934), a novel triepoxidic derivative, this compound was tested in a series of murine transplantable tumors. Repeated daily treatments with well-tolerated systemic doses of this chemical produced substantial retardation in tumor growth and significant prolongation of survival in the line 16 mammary, M5067 ovarian, and Madison 109 lung carcinomas and in mFS6 fibrosarcoma. Very marked activity was also seen in the P815 mastocytoma, B16 melanoma, line 38 colon carcinoma, and an intracerebrally transplanted ependymoblastoma, with high proportions of cures after one or two injections in IP transplanted SL2 lymphoma and line 26 colon carcinoma. It is concluded that the high level of antineoplastic effectiveness and the wide spectrum of TGT activity together with its novel structural characteristics could be of clinical significance.  相似文献   
42.
Seizures and civilian head injuries   总被引:4,自引:3,他引:1  
Although several studies have reported on the risk of "early seizures" (seizures occurring within 7 days following a head injury), the reported proportions of patients experiencing these seizures vary from 1.4 to 15%. This wide divergence may be due to problems with methodology such as case selection and definitions of head injury and early seizures. In a series of 702 patients admitted with a head injury to Cook County Hospital (CCH), Chicago, Illinois, 29 (4.1%) had early seizures. This proportion is twice as high as one previously reported in a comparable series. This may reflect an actual difference between the two series or a case selection bias serving to elevate the proportion of patients with early seizures at CCH.  相似文献   
43.
PURPOSE: Fenretinide (4HPR), a synthetic retinoid, induces apoptosis in neuroblastoma cells. A Phase I study in children with neuroblastoma was designed to determine maximum tolerated dose, toxicity, and pharmacokinetics. EXPERIMENTAL DESIGN: Fifty-four patients received oral 4HPR, once daily, for 28 days, followed by a 7-day interruption, for up to 6 courses. The starting dose was 100 mg/m(2)/day. At least 3 patients were entered at each escalating 4HPR dose level. Pharmacokinetic sampling was performed on days 1 and 28 of the first course. RESULTS: Fifty-four patients, of whom 53 were evaluable, received doses between 100 and 4000 mg/m(2)/day for a total of 168 courses. Additional dose escalation was precluded by capsule number intake. A total of 34 of 53 evaluable patients showed manageable, reversible toxicities, which were not dose related. One dose-limiting toxicity (nyctalopia grade 3) occurred after the 1000 mg/m(2)/day dose. Twelve patients showed grade 2 toxicity: skin xerosis (6 cases); nyctalopia (3 cases); hepatic toxicity (1 case); diarrhea (1 case); and headache (1 case). Stable disease was observed in 41 patients for a median period of 23 months (range 2-35+). After first administration, average 4HPR peak plasma levels ranged from 0.6 to 6 micro M (after 100 and 4000 mg/m(2)/day, respectively) and increased 2-fold (to 1.3 and 12.9 micro M, respectively) after the 28-day treatment. 4HPR half-life increased from 17 h after the first administration to 25 h after the 28(th) administration. Incidence of grade 2-3 toxicity was 0 of 12 (0%), 7 of 22 (31%), and 4 of 8 (50%) with peak 4HPR concentrations <3 micro M, 3-10 micro M, and >10 micro M, respectively. After repeated treatment, retinol levels decreased from 20 to 10% of pretreatment levels after all of the doses. CONCLUSIONS: In children, 4HPR administration up to 4000 mg/m(2)/day over 28 days, followed by a 7-day interruption, results in manageable toxicity and in drug plasma concentrations comparable with those that induce apoptosis in neuroblastoma cell lines.  相似文献   
44.
MR imaging of the neonatal brain at 3 Tesla   总被引:1,自引:0,他引:1  
3 Telsa MR scanners are now becoming more widely available and 3 Telsa is likely to become the filed strength of choice for clinical imaging of the brain. The neonatal brain can be safely and successfully imaged at 3 Telsa. The improved signal to noise afforded by a higher field strength may be used to improve image quality or shorten acquisition times. This may be exploited for conventional T1 and T2 weighted imaging and also for advanced techniques such as diffusion tensor imaging, angiography and functional magnetic resonance studies.  相似文献   
45.
Interleukin-6 (IL-6) protects multiple myeloma cells against apoptosis induced by glucocorticoids. Here, we investigated whether inhibition of the IL-6 signaling pathway by the IL-6 receptor superantagonist Sant7 enhances the in vivo antitumor effects of dexamethasone on the IL-6-dependent multiple myeloma cell line INA-6. For this purpose, we used a novel murine model of human multiple myeloma in which IL-6-dependent INA-6 multiple myeloma cells were directly injected into human bone marrow implants in severe combined immunodeficient (SCID) mice (SCID-hu). The effect of in vivo drug treatments on multiple myeloma cell growth was monitored by serial determinations of serum levels of soluble IL-6 receptor (shuIL-6R), which is released by INA-6 cells and served as a marker of tumor growth. In SCID-hu mice engrafted with INA-6 cells, treatment with either Sant7 or dexamethasone alone did not induce significant reduction in serum shuIL-6R levels. In contrast, the combination of Sant7 with dexamethasone resulted in a synergistic reduction in serum shuIL-6R levels after 6 consecutive days of treatment. Gene expression profiling of INA-6 cells showed down-regulation of proliferation/maintenance and cell cycle control genes, as well as up-regulation of apoptotic genes in multiple myeloma cells triggered by Sant7 and dexamethasone combination. In vitro colony assays showed inhibition of myeloid and erythroid colonies from normal human CD34(+) progenitors in response to dexamethasone, whereas Sant7 neither inhibited colony growth nor potentiated the inhibitory effect of dexamethasone. Taken together, these results indicate that inhibition of IL-6 signaling by Sant7 significantly potentiates the therapeutic action of dexamethasone against multiple myeloma cells, providing the preclinical rationale for clinical trials of Sant7 in combination with dexamethasone to improve patient outcome in multiple myeloma.  相似文献   
46.
The laryngeal mask for intubation (MLI), or "Fastrach", is a new device designed by Brain for airway management. The MLI, a modified version of the conventional laryngeal mask, allows for blind intubation through the device using endotracheal tubes up to 8 mm in diameter. Insertion with the head in a neutral position makes this system useful for managing the airway when neck injury is present. The device has been used successfully in patients assessed as having difficult-to-manage airways and its use in emergencies inside or outside the hospital is promising. The MLI has been used with high rates of success in combination with other techniques such as fiberoptic bronchoscopy (success rate 99 to 100%) and transillumination (95 to 100% success rate) in patients whose airways have been considered difficult to manage. Given such high rates of success for MLI placement (95 to 100%) and for blind orotracheal intubation (81 to 100%), the Fastrach may offer an alternative to the conventional laryngeal mask in algorithms for airway management.  相似文献   
47.
48.
The ankylosed spine is prone to fracture even after minor trauma due to its changed biomechanical properties. The two central features of ankylosing spondylitis (AS) that promote the pathological remodeling of the spine are inflammation and new bone formation. AS is also associated with osteoporosis that is attributed to an uncoupling of the bone formation and bone resorption processes. Therefore, bone resorption occurs and promotes weakening of the spine as well as increased risk of vertebral fractures which can be hugely different in terms of clinical relevance. Even in the presence of symptomatic clinical vertebral fractures, the diagnosis can be overruled by attributing the pain to disease activity. Furthermore, given the highly abnormal structure of the spine, vertebral fracture diagnosis can be difficult on the basis of radiography alone. CT can show the fractures in detail. Magnetic resonance imaging is considered the method of choice for the imaging of spinal cord injuries, and a reasonable option for exclusion of occult fractures undetected by CT. Since it is equally important for radiologists and clinicians to have a common knowledge base rather than a compartmentalized view, the aim of this review article was to provide the required clinical knowledge that radiologists need to know and the relevant radiological semiotics that clinicians require in diagnosing clinically significant injury to the ankylosed spine.  相似文献   
49.
50.
Recently, a meta-analysis, including 26?526 laboring vertex singletons at term, summarized all available level-1 data from six high-quality randomized clinical trials (RCTs) on the use of ST analysis (STAN) during labor as an adjunct to conventional intrapartum fetal heart rate monitoring. The meta-analysis showed that STAN did not improve perinatal outcomes or decrease cesarean deliveries. Nonetheless, there are still reasons to believe STAN may have a role in the future research on intrapartum fetal monitoring. Out of six trials included in the meta-analysis, two included all cephalic singletons in labor, and four enrolled only high-risk pregnant women. This combination of both low- and high-risk populations may have distorted the potential impact of STAN. The test for heterogeneity between both subgroups was found to be statistically significant, indicating that the effect of STAN was different in high-risk women compared to a combination of both low- and high-risk women. Furthermore, the classifications of the fetal heart rate patterns used in the included randomized trials were different. Last but not least, despite?>26?000 women with singleton gestations were included in the meta-analysis, the evidence still suffers from a lack of power, especially for subgroup analyses. In summary, while the level-1 data so far indicate overall no perinatal benefit of adding STAN to conventional intrapartum fetal heart rate monitoring for the outcomes most of interest, several issues point to the fact that more research is needed before the STAN technology can be deemed of no value for fetal monitoring in labor.  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