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   242321篇
  免费   17216篇
  国内免费   871篇
耳鼻咽喉   2606篇
儿科学   6370篇
妇产科学   4963篇
基础医学   31806篇
口腔科学   7420篇
临床医学   22608篇
内科学   51485篇
皮肤病学   3426篇
神经病学   22723篇
特种医学   7611篇
外国民族医学   14篇
外科学   36439篇
综合类   3828篇
现状与发展   2篇
一般理论   299篇
预防医学   22671篇
眼科学   4784篇
药学   16725篇
  1篇
中国医学   684篇
肿瘤学   13943篇
  2023年   1142篇
  2022年   2102篇
  2021年   4596篇
  2020年   2902篇
  2019年   4420篇
  2018年   5134篇
  2017年   4090篇
  2016年   4317篇
  2015年   5095篇
  2014年   7448篇
  2013年   10449篇
  2012年   15624篇
  2011年   17014篇
  2010年   9526篇
  2009年   8369篇
  2008年   15414篇
  2007年   16181篇
  2006年   15509篇
  2005年   15706篇
  2004年   14966篇
  2003年   13921篇
  2002年   13355篇
  2001年   2552篇
  2000年   2203篇
  1999年   2620篇
  1998年   3028篇
  1997年   2587篇
  1996年   2349篇
  1995年   2088篇
  1994年   1866篇
  1993年   1750篇
  1992年   1493篇
  1991年   1408篇
  1990年   1316篇
  1989年   1179篇
  1988年   1242篇
  1987年   1196篇
  1986年   1152篇
  1985年   1220篇
  1984年   1604篇
  1983年   1559篇
  1982年   1865篇
  1981年   1687篇
  1980年   1593篇
  1979年   903篇
  1978年   1048篇
  1977年   982篇
  1976年   876篇
  1975年   743篇
  1974年   742篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
56.
We reviewed the results of all pediatric patients undergoing intracranial pressure (ICP) monitoring in a 2-year period at our institution. The outcome of patients suffering hypoxia or ischemic injuries (HII) is compared to those suffering non-hypoxic or non-ischemic injuries (NHII). Thirty-four patients had ICP monitors placed during the study period. Inconplete patient information led to the exclusion of 5 patients. An additional 5 patients were excluded because no measures to control ICP were taken after the monitor was placed. Twenty-four patients required treatment for raised ICP (hyperventilation, 24; mannitol, 19; barbiturate coma, 6). Admission Glasgow Coma Score in patients suffering HII (median score 5) and NHII (median score 6) were not significantly different (Mann-Whitney U Test). Only 2 of 8 patients with HII were near-drowning vietims. The remaining 6 had HII from other causes (5 survivors of various forms of asphyxia and 1 of cardiac arrest). All 8 patients had poor outcomes (1 severely disabled; 7 died). The 16 patients with NHII had a variety of diagnoses (6 trauma, 5 encephalitis, 4 bacterial meningitis, 1 diabetic ketoacidosis). Among these, 6 had good outcomes and 10 poor outcomes (2 severely disabled, 2 vegetative, and 6 died). The difference in outcome between patients with NHII and HII is significant at P=0.059 (Fischer Exact test). Patients with NHII may benefit from ICP monitoring. Patients with HII from near-drowning and other causes did not appear to benefit from ICP monitoring and interventions directed at controlling ICP.  相似文献   
57.
Summary Cytosine arabinsodie (ara-C) and etoposide (VP-16) display synergy in the laboratory. Twenty-six patients participated in a phase I study of high-dose ara-C in combination with VP-16. The dose of VP-16 was held constant at 50 mg/m2 as an intermittent infusion over 33 h; escalating doses of ara-C were given as infusions during hours 9–12 and 21–24. Myelosuppression was the dose-limiting toxicity and occurred with doses considerably less than those expected from studies of the two drugs as single agents. The suggested initial doses for phase II trials with this schedule are 750 mg/m2×2 doses of ara-C and 50 mg/m2 of VP-16. Nonhematologic toxicity was minimal; therefore, further dose escalation is feasible in patients in whom myelosuppression is acceptable.Supported in part by grants from the National Cancer Institute (CA-12197 and CA-09422) and the American Cancer Society CF-85-182  相似文献   
58.
OBJECTIVES: Diagnostic accuracy of the ThinPrep process (Cytyc, Boxborough, MA) was compared with that of conventional (smear) cytopreparation for fine-needle aspiration (FNA) of head and neck masses. METHODS: In a prospective, randomized, single-blinded study, 209 patients served as their own controls and underwent 236 FNAs using ThinPrep and conventional (smear) cytopreparatory techniques. RESULTS: ThinPrep produced less air-drying artifact and less mechanical distortion than the conventional method. The conventional technique was diagnostic in 63% of samples; the ThinPrep technique was diagnostic in 55% of samples. When all results were combined, pathologists subjectively preferred the conventional technique but accepted use of ThinPrep as the only cytopreparatory technique for most head and neck masses. CONCLUSIONS: For adequately experienced cytopathologists, ThinPrep is acceptable for FNA of salivary masses, neck cysts, metastatic lymph nodes, and thyroid lesions. Conventional smear technique should be used for FNA of nonmetastatic lymphoid lesions. Use of ThinPrep can complement use of the conventional (smear) cytopreparatory technique when aspirate is nondiagnostic or bloody, when the patient has a blood-borne infectious disease, when the clinician is inexperienced, or when aspirate has entered the syringe.  相似文献   
59.
Molecular chaperones assist in the biosynthesis and processing of proteins. Most chaperones are induced by physiological stresses. We have shown that dietary energy restriction decreases the mRNA and protein levels of many endoplasmic reticulum chaperones in the livers of mice. Here, we have investigated the response of chaperone mRNA to feeding. Control and 50% energy-restricted C3B10RF1 mice were deprived of food for 24 h, fed, and killed 0, 1.5, 5 or 12 h after feeding. Chaperone mRNAs were strongly induced as early as 1.5 h after feeding in control and energy-restricted mice. The integrated levels of these mRNA over 24 h were significantly lower in energy-restricted mice. The mRNA response to energy intake was mirrored over the course of days in the level of chaperone protein. A similar but smaller response to feeding was found in kidney and muscle. Puromycin and cycloheximide failed to inhibit the feeding response, suggesting that feeding releases chaperone expression from an unstable inhibitor. Studies with dibutyryl-cAMP- and glucagon-supplemented, normal and streptozotocin-diabetic mice suggest that glucagon and insulin may be mediators of the feeding response. Adrenalectomy enhanced the feeding induction, but dexamethasone administration had no effect. Thus, postprandial changes in insulin and glucagon may link chaperone gene expression to feeding, possibly in several tissues including liver.  相似文献   
60.
PURPOSE: To review the role of recombinant factor VIIa in anesthetic practice. SOURCE: A review of the published literature. MAIN FINDINGS: The mechanism of action of rFVIIa suggests enhancement of hemostasis limited to the site of injury without systemic activation of the coagulation cascade. In addition to its indication for use in patients with hemophilia, use of rFVIIa for treatment of uncontrolled massive hemorrhage in various peroperative settings appears to be rational, safe, and effective. Published results suggest that in trauma patients rFVIIa may play a role as an adjunctive hemostatic measure in addition to surgical hemostatic techniques There is preliminary evidence that hemorrhagic complications (eg. epistaxis, vaginal bleeding) associated with profound thrombocytopenia can be reversed with rFVIIa even at platelet counts below 10,000 per microL. Various case reports outlining the successful treatment with recombinant factor VIIa of patents experiencing intractable bleeding after valve replacement surgery, and with severe hemorrhage during therapy with left ventricular assist device, indicate the potential therapeutic efficacy of this agent in cardiac surgical procedures. Additionally, rFVIIa has been used successfully for treatment of massive postoperative bleeding following general surgery. CONCLUSIONS: rFVIIa is a novel hemostatic agent that shows promise in non-hemophiliac patents of a significant therapeutic role in variety of coagulopathic and hemorrhagic conditions in clinical situations ranging from thrombocytopenia, disseminated intravascular coagulation and transfusion-related coagulopathy, as well as in patients experiencing massive blood loss undergoing orthotopic liver transplantation, cardiac, orthopedic and genitourinary surgery.  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