全文获取类型
收费全文 | 650篇 |
免费 | 38篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 49篇 |
妇产科学 | 4篇 |
基础医学 | 29篇 |
口腔科学 | 15篇 |
临床医学 | 72篇 |
内科学 | 105篇 |
皮肤病学 | 1篇 |
神经病学 | 6篇 |
特种医学 | 142篇 |
外科学 | 176篇 |
综合类 | 30篇 |
预防医学 | 20篇 |
眼科学 | 2篇 |
药学 | 18篇 |
肿瘤学 | 19篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 18篇 |
2013年 | 19篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 13篇 |
2006年 | 17篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 18篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 30篇 |
1997年 | 34篇 |
1996年 | 35篇 |
1995年 | 34篇 |
1994年 | 32篇 |
1993年 | 20篇 |
1992年 | 17篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 28篇 |
1987年 | 25篇 |
1986年 | 28篇 |
1985年 | 25篇 |
1984年 | 18篇 |
1983年 | 14篇 |
1982年 | 6篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1970年 | 3篇 |
排序方式: 共有693条查询结果,搜索用时 31 毫秒
61.
Baker LL; Hajek PC; Burkhard TK; Dicapua L; Leopold GR; Hesselink JR; Mattrey RF 《Radiology》1987,163(1):89-92
High-resolution magnetic resonance (MR) imaging with a surface coil was utilized to evaluate the normal scrotum. Scrotal contents, spermatic canal, and inguinal regions were visualized within the same field of view. Differences in signal intensity in the testis, epididymis, tunica albuginea, fluid, fat, and spermatic cord allowed for clear delineation of these structures in detail. The high contrast and spatial resolution of MR imaging, coupled with the wide field of view and absence of ionizing radiation, make MR imaging well suited for evaluation of the scrotum. 相似文献
62.
Peptic ulcer and gastric carcinoma: diagnosis with biphasic radiography compared with fiberoptic endoscopy 总被引:1,自引:0,他引:1
Shaw PC; van Romunde LK; Griffioen G; Janssens AR; Kreuning J; Eilers GA 《Radiology》1987,163(1):39-42
The diagnostic value of biphasic radiographic examination of the stomach and duodenum was compared with that of fiberoptic endoscopy in a prospective, blinded study of 385 patients with dyspepsia. This investigation was directed at gastric malignancies and peptic ulcers. Methodologically there is no absolute standard for a study of this kind because histologic examination is useful for detection of cancer but inadequate for ulcers. As an alternative, kappa indexes and the sensitivity and specificity, as derived by Hui and Walter, were calculated and compared. For the detection of gastric carcinoma, radiographic and endoscopic findings had almost perfect agreement beyond chance. For gastric ulcers, radiography and endoscopy had substantial agreement, which became perfect if small ulcers (less than 5 mm) were excluded. For duodenal ulcers, radiography had a lower sensitivity than endoscopy; this disagreement disappeared if small ulcers were excluded. Both methods have equal merit; choice of the initial diagnostic procedure will therefore depend on cost, discomfort to the patient, and risk of complications. 相似文献
63.
Anthropomorphic radiologic phantoms 总被引:1,自引:0,他引:1
A technique is being developed for the design and fabrication of anthropomorphic phantoms for diagnostic x-ray imaging. Anatomic information extracted from actual patient radiographs is incorporated into the phantoms using computer image processing and computer-assisted machining methods. In this paper, the technique is described as applied to a breast phantom, and preliminary images that closely mimic human anatomy on radiographs are shown. 相似文献
64.
Technical principles of direct innominate artery revascularization: a comparison of endarterectomy and bypass grafts 总被引:3,自引:0,他引:3
K J Cherry J L McCullough J W Hallett P C Pairolero P Gloviczki 《Journal of vascular surgery》1989,9(5):718-23; discussion 723-4
Occlusive lesions of the innominate artery that require operation occur infrequently. Direct repair has been performed with low morbidity and mortality. There is debate over the best method of direct reconstruction. Twenty-six patients undergoing transsternal innominate artery repair over a 12-year period were reviewed to determine if either grafting or endarterectomy was superior and what technical factors might be responsible for success or failure. Most of the patients were women. Twenty-four of the patients had atherosclerotic lesions, whereas the other two had Takayasu's arteritis. Either neurologic or right upper extremity symptoms were present in 24 patients. Sixteen patients had grafting, and 10 underwent endarterectomy. There was one death. There were no strokes or transient ischemic attacks. Three patients experienced recurrence of their symptoms; all had failures of reconstruction. The use of a bifurcated graft in one patient was probably responsible for one recurrence of symptoms. Single limb grafts with added side arms are probably preferable to bifurcated grafts. Innominate artery grafting and innominate endarterectomy are equally effective, although grafting is applicable to more patients. Direct transsternal repair is the procedure of choice to correct innominate occlusive disease in patients who are good candidates for correction. 相似文献
65.
66.
A microcapillary method utilizing phthalate esters or an ultracentrifuge method are both capable of separating autologous from homologous erythrocytes in polytransfused patients. The microcapillary technique which is readily adaptable to blood bank laboratories provides a previously unavailable method for defining blood group antigen typings in transfused patients. Such typings are of vital importance in the laboratory evaluation of transfused patients with multiple or weak blood group antibodies. 相似文献
67.
Total radical trapping antioxidant potential (TRAP) and exercise 总被引:1,自引:0,他引:1
Sharpe PC; Duly EB; MacAuley D; McCrum EE; Mulholland C; Stott G; Boreham CA; Kennedy G; Evans AE; Trinick TR 《QJM : monthly journal of the Association of Physicians》1996,89(3):223-228
The relationship between physical activity, physical fitness and total
radical trapping antioxidant potential (TRAP) was examined in the Northern
Ireland Health and Activity Survey. This was a cross-sectional population
study (n = 1600) using a two-stage probability sample of the population.
TRAP was calculated using the sum of the individual serum antioxidant
concentrations (urate, protein thiols, ascorbate, alpha tocopherol and
bilirubin) multiplied by their respective stoichiometric values. Physical
fitness was determined by estimation of VO2max by extrapolation from
submaximal oxygen uptake, and physical activity was recorded by
computer-assisted interview. Mean serum TRAP concentrations were
significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared
to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female
smokers had significantly lower TRAP values than non-smokers (males p <
0.0001, females p = 0.02). In females, there was a positive relationship of
TRAP with age (p < 0.001) and body mass index (p < 0.001) but a
negative relationship with physical fitness (p < 0.05). The known
beneficial effects of exercise and activity do not appear to be directly
mediated through increased antioxidant status.
相似文献
68.
HE Connor W Feniuk DT Beattie PC North AW Oxford DA Saynor PPA Humphrey 《Cephalalgia : an international journal of headache》1997,17(3):145-152
The biological profile of naratriptan (N-methyl-3-(1-methyl-4-piperidinyl)-1H-indole-5-ethane-sulphona-mide), a novel 5HT1B/1D receptor agonist, was investigated in a variety of experimental models of relevance to migraine. Naratriptan has high affinity for human recombinant 5HT1B and 5HT1D receptors (pKi = 8.70.03 and 8.30.1, respectively) and causes contractions of dog isolated basilar and middle cerebral artery (EC50 values of 0.11 and 0.07 M, respectively). Naratriptan causes small contractions of human isolated coronary arteries (EC50 value of 0.17 M; maximum contraction equivalent to 33% of 5HT maximum). In anaesthetized dogs, naratriptan causes selective vasoconstriction of the carotid arterial bed (CD50 dose = 193 g kg−1 ) and, in anaesthetized rats, naratriptan selectively inhibits neurogenic plasma protein extravasation in the dura (ID50 = 4.1 g kg−1 ). In a variety of antinociceptive tests, naratriptan has no effect even at high doses. In conscious rats and dogs, naratriptan has high oral bioavailability (71% and 95%, respectively). The data show that naratriptan is a selective agonist at 5HT1B/1D receptors, with a pharmacological profile very similar to that of sumatriptan, albeit 2-3 fold more potent. These observations, coupled with high oral bioavailability in animals, suggest that naratriptan has the profile of an orally effective anti-migraine drug. 相似文献
69.
70.
Fradet Y Grossman HB Gomella L Lerner S Cookson M Albala D Droller MJ;PC B/ Study Group 《The Journal of urology》2007,178(1):68-73; discussion 73
PURPOSE: We compared hexaminolevulinate (Hexvix) fluorescence cystoscopy with white light cystoscopy for detecting carcinoma in situ. MATERIALS AND METHODS: In this multicenter study 298 patients with known or suspected bladder cancer underwent bladder instillation with 50 ml 8 mM hexaminolevulinate for 1 hour. Cystoscopy was then performed, first using standard white light and then hexaminolevulinate fluorescence cystoscopy. Lesions or suspicious areas identified under the 2 illumination conditions were mapped and biopsied for histological examination. In addition, 1 directed biopsy was obtained from an area appearing to be normal. RESULTS: Of 196 evaluable patients 29.6% (58 of 196) had carcinoma in situ, including 18 with carcinoma in situ alone, and 35 with carcinoma in situ and concomitant papillary disease, which was only detected on random biopsy in 5. Of the 18 patients with no concomitant papillary disease carcinoma in situ was detected only by hexaminolevulinate fluorescence in 4 and only by white light in 4. In the group with concomitant papillary disease carcinoma in situ was found only by hexaminolevulinate fluorescence in 5 patients and only by white light in 3. The proportion of patients in whom 1 or more carcinoma in situ lesions were found only by hexaminolevulinate cystoscopy was greater than the hypothesized 5% (p=0.0022). Overall more carcinoma in situ lesions were found by hexaminolevulinate than by white light cystoscopy in 22 of 58 patients (41.5%), while the converse occurred in 8 of 58 (15.1%). Biopsy results confirmed cystoscopy findings. Of a total of 113 carcinoma in situ lesions in 58 patients 104 (92%) were detected by hexaminolevulinate cystoscopy and 77 (68%) were detected by white light cystoscopy, while 5 were detected only on directed visually normal mucosal biopsy. Hexaminolevulinate instillation was well tolerated with no local or systemic side effects. CONCLUSIONS: In patients with bladder cancer hexaminolevulinate fluorescence cystoscopy with blue light can diagnose carcinoma in situ that may be missed with white light cystoscopy. Hexaminolevulinate fluorescence cystoscopy can be used in conjunction with white light cystoscopy to aid in the diagnosis of this form of bladder cancer. 相似文献