全文获取类型
收费全文 | 1513940篇 |
免费 | 104171篇 |
国内免费 | 3391篇 |
专业分类
耳鼻咽喉 | 20871篇 |
儿科学 | 49242篇 |
妇产科学 | 41389篇 |
基础医学 | 222799篇 |
口腔科学 | 42152篇 |
临床医学 | 131071篇 |
内科学 | 297521篇 |
皮肤病学 | 33108篇 |
神经病学 | 114331篇 |
特种医学 | 58620篇 |
外国民族医学 | 405篇 |
外科学 | 232433篇 |
综合类 | 32335篇 |
现状与发展 | 2篇 |
一般理论 | 393篇 |
预防医学 | 109917篇 |
眼科学 | 34592篇 |
药学 | 111366篇 |
3篇 | |
中国医学 | 3935篇 |
肿瘤学 | 85017篇 |
出版年
2018年 | 15712篇 |
2017年 | 12295篇 |
2016年 | 13514篇 |
2015年 | 15230篇 |
2014年 | 21155篇 |
2013年 | 32376篇 |
2012年 | 43146篇 |
2011年 | 45692篇 |
2010年 | 27505篇 |
2009年 | 25993篇 |
2008年 | 43271篇 |
2007年 | 46252篇 |
2006年 | 46689篇 |
2005年 | 45097篇 |
2004年 | 43517篇 |
2003年 | 41813篇 |
2002年 | 40997篇 |
2001年 | 72135篇 |
2000年 | 73826篇 |
1999年 | 62222篇 |
1998年 | 16836篇 |
1997年 | 14934篇 |
1996年 | 15036篇 |
1995年 | 14205篇 |
1994年 | 13304篇 |
1993年 | 12375篇 |
1992年 | 48048篇 |
1991年 | 46867篇 |
1990年 | 45844篇 |
1989年 | 44589篇 |
1988年 | 40985篇 |
1987年 | 40168篇 |
1986年 | 38435篇 |
1985年 | 36302篇 |
1984年 | 26942篇 |
1983年 | 22959篇 |
1982年 | 13320篇 |
1979年 | 24824篇 |
1978年 | 17403篇 |
1977年 | 14732篇 |
1976年 | 14077篇 |
1975年 | 15480篇 |
1974年 | 18350篇 |
1973年 | 17510篇 |
1972年 | 16520篇 |
1971年 | 15331篇 |
1970年 | 14773篇 |
1969年 | 13750篇 |
1968年 | 12921篇 |
1967年 | 11815篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
BACKGROUND: Tinnitus is an uncomfortable symptom for the patient and an embarrassing one for the consulted physician. So far, there is no treatment that can be considered well established in terms of providing long-term reduction of tinnitus in excess of placebo effects. There is considerable evidence of pathophysiological similarity between tinnitus and chronic pain. Some forms of chronic pain can be treated by neurostimulation. OBJECTIVE: This study was designed to investigate the feasibility of neurostimulation of the cochlear nerve in order to reduce tinnitus. STUDY DESIGN: Pilot study. SETTING: Tertiary referral center. PATIENTS: Five patients with therapeutically refractory tinnitus were selected for this study. INTERVENTION: Placing a stimulation lead around the cochlear nerve through the suboccipital approach and connecting the stimulation lead to a pulse generator. MAIN OUTCOME MEASURES: The patients experienced 1) an absence of major or minor complications, such as death, meningitis, cranial nerve deficit, and vestibular problems; 2) tolerance of the procedure as considered by the patient; 3) relief of tinnitus in at least one patient. RESULTS: Implantation of the neurostimulation system was accomplished in each patient without any difficulty. None of the patients considered the treatment unbearable. No major or minor complications occurred in this study. Subjective tinnitus reduction was accomplished in four patients. CONCLUSION: Our preliminary data show that neurostimulation of the cochlear nerve is feasible, is bearable for the patient, and is a safe treatment modality without major complications. The effects on tinnitus are promising. 相似文献
972.
Effects of halothane on spinal dorsal horn WDR(wide dynamic range) neuronal activity in cats 总被引:1,自引:0,他引:1
H Nagasaka S Nakamura T Genda T Miyazaki K Aikawa N Matsumoto I Matsumoto T Hori I Sato 《Masui. The Japanese journal of anesthesiology》1991,40(7):1096-1101
The effects of halothane (0.2%, 0.5%, and 1.0%) on the spinal dorsal horn wide dynamic range (WDR) neuronal activity was studied in either spinal cord intact or spinal transected cats. Extracellular activity was recorded in the dorsal horn from single WDR neurons responding to noxious and non-noxious stimuli applied to the cutaneous receptive fields on the left hind foot pads of intact or decerebrate, spinal cord transected (L 1-2) cats. When 10 micrograms of bradykinin was injected into the femoral artery ipsilateral to the recording site as the noxious test stimulus in the spinal cat, all of 7 WDR neurons gave excitatory responses which were not depressed by 0.2% and 0.5% halothane but were depressed significantly by 1.0%. On the other hand, when the injection of 10 micrograms of bradykinin into the femoral artery ipsilateral to the recording site was used in the intact cat, 7 of 14 WDR neurons (50%) gave excitatory responses, which were not depressed by 0.2% halothane but were significantly depressed by 0.5% and 1.0% halothane, and 7 of 14 WDR neurons (50%) gave inhibitory responses, which were significantly depressed by 0.2%, 0.5%, and 1.0% halothane. We have found that halothane reduces the excitation as well as the inhibition of dorsal horn WDR neuronal activity induced by bradykinin injection. 相似文献
973.
David L. Healey B.D.S. Nicholas P. Chandler B.D.S. F.D.S. F.F.D. 《The Journal of prosthetic dentistry》1991,66(6):727-729
Experiments were performed to determine the effect of pin channel preparation with standard and reduction speed handpieces, and pin seating by hand and with motor drive. The greatest retention was achieved by preparation with a standard handpiece at 6000 rpm, and manual pin placement with a hand driver. The most consistent retention values were achieved using the reduction handpiece. All preparation and placement combinations examined produced a clinically acceptable result. 相似文献
974.
P Toulon J F Vitoux J N Fiessinger D Sicard M Aiach 《Blood coagulation & fibrinolysis》1991,2(3):435-439
In human plasma, heparin cofactor II (HCII) is a thrombin inhibitor which displays similarities with antithrombin III (ATIII). As previously reported for hereditary ATIII deficiency, cases of recurrent thrombosis were reported in patients with hereditary HCII deficiency. Here, plasma HCII activity was studied in 372 patients with a history of thrombosis, classified according to their anticoagulant therapy. The mean plasma HCII level was significantly higher in patients with acute deep vein thrombosis (DVT) under heparin therapy than in patients with a history of thrombosis, who were studied more than 3 months after the acute event, and were either on, or had been on, oral anticoagulant therapy. HCII and fibrinogen were significantly correlated in all three groups of patients. These results were strengthened by those of a follow-up study in 23 patients with acute DVT. Changes in plasma HCII activity paralleled those of fibrinogen. This suggests that HCII might behave like an acute phase reactant in patients with thrombosis and that the measurement of its plasma level as a risk factor for thrombosis should be performed some time after the acute episode. In conclusion, the prevalence of HCII deficiency in patients with a history of thrombosis might have been underestimated in series which included patients with acute thrombosis. 相似文献
975.
S J Graafsma H Wollersheim H T Droste M A ten Dam L J van Tits J Reyenga J F Rodrigues de Miranda T Thien 《Clinical science (London, England : 1979)》1991,80(4):325-331
1. alpha 2-Adrenoceptors on platelet membranes and beta 2-adrenoceptors on lymphocytes were studied in 24 patients with primary Raynaud's phenomenon and in 24 age- and sex-matched control subjects. In two subgroups, a standardized mental arithmetic test and a finger-cooling test were performed. 2. Baseline blood pressure, heart rate and forearm blood flow did not differ between the two groups. 3. Baseline skin microcirculation (laser Doppler flux) was decreased in primary Raynaud's phenomenon (19 +/- 15 arbitrary units) compared with control subjects (33 +/- 14 arbitrary units) (P less than 0.01). 4. Baseline plasma noradrenaline concentration (2.00 +/- 1.44 versus 1.16 +/- 0.36 nmol/l) and alpha 2-adrenoceptor density (301 +/- 119 versus 210 +/- 82 fmol/mg) were increased in patients with primary Raynaud's phenomenon in comparison with the control subjects. The alpha 2-adrenoceptor density/beta 2-adrenoceptor density ratio in patients with primary Raynaud's phenomenon was, with a value of 0.37 +/- 0.04, higher than in the control subjects, where a value of 0.25 +/- 0.02 was measured (P less than 0.001). Plasma adrenaline concentration, beta 2-adrenoceptor density and the antagonist affinity to both receptor subtypes did not differ between both groups under baseline conditions. 5. Whereas during the finger-cooling test no differences were seen in the responses of the parameters measured, the mental arithmetic test induced an increase in laser Doppler flux in patients with primary Raynaud's phenomenon and a decrease in the control group.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
976.
Design and conduct of occupational epidemiology studies: III. Design aspects of case-control studies
Currently available approaches for the design of occupational case-control studies are reviewed. An accompanying paper reviews methods of analysis. We commence by drawing a distinction between cohort-based and registry-based studies. Methods for selecting cases and controls are then reviewed, including cumulative incidence and incidence density sampling, matching, sources of controls, and issues in control selection. Finally, the advantages and disadvantages of the case-control approach are summarized. 相似文献
977.
In clinical diagnosis, a patient's symptoms are observed and the probabilities of various diseases are assessed. A widely used method of formalizing this approach is independent Bayes in which symptoms are assumed to be independent conditional on the disease category. Correspondence analysis provides a method for examining the dependence between symptoms and assists in the selection of a reduced set of symptoms for the application of the independent Bayes method. This approach is illustrated on two data sets concerned with patients attending Accident and Emergency departments with chest pain and acute abdominal pain, respectively. 相似文献
978.
Translated from Khimiko-farmatsevticheskii Zhurnal, Vol. 23, No. 5, pp. 540–549, May, 1989. 相似文献
979.
980.
M Regallo S Scalambrino L Negri F Landoni C Mangioni 《Drugs under experimental and clinical research》1989,15(6-7):315-320
A prospective randomized study was carried out on a total of 686 patients who underwent vaginal or abdominal hysterectomy. Of these, 338 were given prophylactic cefotetan (2 g) and 348 piperacillin (2 g). Both drugs were administered as i.v. bolus 30 min before operation. Findings confirm the higher risk of infection with abdominal hysterectomy and the advantages of the long half-life cephalosporin, cefotetan. 相似文献