全文获取类型
收费全文 | 3958篇 |
免费 | 324篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 80篇 |
妇产科学 | 84篇 |
基础医学 | 606篇 |
口腔科学 | 57篇 |
临床医学 | 354篇 |
内科学 | 930篇 |
皮肤病学 | 55篇 |
神经病学 | 296篇 |
特种医学 | 232篇 |
外科学 | 548篇 |
综合类 | 119篇 |
一般理论 | 2篇 |
预防医学 | 200篇 |
眼科学 | 31篇 |
药学 | 365篇 |
中国医学 | 10篇 |
肿瘤学 | 239篇 |
出版年
2023年 | 28篇 |
2022年 | 54篇 |
2021年 | 128篇 |
2020年 | 55篇 |
2019年 | 73篇 |
2018年 | 118篇 |
2017年 | 96篇 |
2016年 | 89篇 |
2015年 | 97篇 |
2014年 | 147篇 |
2013年 | 217篇 |
2012年 | 317篇 |
2011年 | 327篇 |
2010年 | 195篇 |
2009年 | 136篇 |
2008年 | 232篇 |
2007年 | 243篇 |
2006年 | 227篇 |
2005年 | 202篇 |
2004年 | 208篇 |
2003年 | 180篇 |
2002年 | 176篇 |
2001年 | 41篇 |
2000年 | 43篇 |
1999年 | 47篇 |
1998年 | 27篇 |
1997年 | 37篇 |
1996年 | 29篇 |
1995年 | 27篇 |
1994年 | 16篇 |
1993年 | 16篇 |
1992年 | 32篇 |
1991年 | 29篇 |
1990年 | 29篇 |
1989年 | 25篇 |
1988年 | 28篇 |
1987年 | 22篇 |
1986年 | 25篇 |
1985年 | 37篇 |
1984年 | 15篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 18篇 |
1980年 | 22篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 15篇 |
1975年 | 16篇 |
1973年 | 16篇 |
排序方式: 共有4316条查询结果,搜索用时 15 毫秒
41.
D. S. Stokic´ W. Barry McKay Lillian Scott Arthur M. Sherwood Milan R. Dimitrijevic´ 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,117(3):437-443
The aim of the present study was to determine the characteristics of intracortical inhibition in the motor cortex areas representing
lower limb muscles using paired transcranial magnetic (TMS) and transcranial electrical stimulation (TES) in healthy subjects.
In the first paradigm (n=8), paired magnetic stimuli were delivered through a double cone coil and motor evoked potentials (MEPs) were recorded from
quadriceps (Q) and tibialis anterior (TA) muscles during relaxation. The conditioning stimulus strength was 5% of the maximum
stimulator output below the threshold MEP evoked during weak voluntary contraction of TA (33±5%). The test stimulus (67±2%)
was 10% of the stimulator output above the MEP threshold in the relaxed TA. Interstimulus intervals (ISIs) from 1–15 ms were
examined. Conditioned TA MEPs were significantly suppressed (P<0.01) at ISIs of less than 5 ms (relative amplitude from 20–50% of the control). TA MEPs tended to be only slightly facilitated
at 9-ms and 10-ms ISIs. The degree of MEP suppression was not different between right and left TA muscles despite the significant
difference in size of the control responses (P<0.001). Also, conditioned MEPs were not significantly different between Q and TA. The time course of TA MEP suppression,
using electrical test stimuli, was similar to that found using TMS. In the second paradigm (n=2), the suppression of TA MEPs at 2, 3, and 4 ms ISIs was examined at three conditioning intensities with the test stimulation
kept constant. For the pooled 2- to 4-ms ISI data, relative amplitudes were 34±6%, 61±5%, and 98±9% for conditioning intensities
of 0.95, 0.90, and 0.85× active threshold, respectively (P<0.01). In conclusion, the suppression of lower limb MEPs following paired TMS showed similar characteristics to the intracortical
inhibition previously described for the hand motor area.
Received: 21 June 1996 / Accepted: 23 May 1997 相似文献
42.
Ivana Vančurová Miroslav Flieger Jindřich Volc Milan J. Beneš Jana Novotná Jiří Neužil Vladislav Běhal 《Journal of basic microbiology》1987,27(9):529-533
Anhydrotetracycline oxygenase was purified both by affinity chromatography and by hydrophobic interaction chromatography. Molecular weight of anhydrotetracycline oxygenase was determined to be 115,000 by Sephadex G-200 gel filtration. Using preparative isoelectric focusing the isoelectric point of the enzyme was estimated to be 5.3. The enzyme showed a sensitivity to thiol-specific inhibitors. During the hydrophobic interaction purification step, the activity dropped considerably. Reactivation occurred when a heat treated crude extract was added to the reaction mixture. 相似文献
43.
Mixed epithelial and stromal tumors of the kidney. A report of 22 cases 总被引:16,自引:0,他引:16
Michal M Hes O Bisceglia M Simpson RH Spagnolo DV Parma A Boudova L Hora M Zachoval R Suster S 《Virchows Archiv : an international journal of pathology》2004,445(4):359-367
Mixed epithelial and stromal tumor of the kidney (MESTK) is a recently described subset of renal neoplasm that tends to occur in middle-aged and older women and is characterized by a distinctive histological appearance. To further characterize this lesion, we report the clinicopathological and immunohistochemical features of 22 additional cases from our institutional files. Grossly, the tumors ranged in size from 1 cm to 14 cm (mean 6.7 cm), were well circumscribed but unencapsulated, and showed a cystic cut surface. The tumors were composed of a spindle cell proliferation that resembled ovarian stroma, as well as an epithelial component lining the cystic structures, which usually consisted of flat to hobnailed cells typical of collecting-duct epithelium. Areas displaying features of Müllerian differentiation were also documented in 6 cases, including epithelium of endometrioid, tubal, clear cell and squamous cell type as well as one case showing an architecture that closely resembled Müllerian adenofibroma and adenosarcoma. Follow-up in 14 patients (average 4.4 years) showed no evidence of recurrence or metastasis. We believe these tumors represent the renal counterpart of similar mixed epithelial and stromal neoplasms occurring in the biliary tract and pancreas, which is also characterized by cystic structures lined by epithelium, admixed with ovarian-type stroma. The differential diagnosis for these tumors includes cystic nephroma and cystic partially differentiated nephroblastoma, which we believe to represent clinically and morphologically distinct entities from MESTK. In particular, the distinction from cystic nephroma in adult male patients is emphasized, and two cases of this entity are included in the study for comparison. 相似文献
44.
Ladislav Novotný Hassan Farghali Miloš Ryba Ivo Janků Jiří Beránek 《Cancer chemotherapy and pharmacology》1984,13(3):195-199
Summary Both transport and biotransformation processes for a series of pyrimidine nucleobases, ribonucleosides, 2-deoxyribonucleosides, and acetyl and 5-substituted derivatives of the cancerostatic agent araC were studied in the isolated everted rat jejunum with a continuous perfusion technique. Metabolic alterations during penetration were assessed by HPLC. 5-Halogeno and 5-deoxy derivatives of cytosine nucleosides exhibited higher transport rates and higher stability towards the deamination reaction than did unsubstituted derivatives. Octanol-buffer partition coefficients were estimated for the study compounds, and fragmental constants for the sugar moieties of nucleosides were assessed. With the present study compounds there was no correlation between lipophilicity and transport rate, as previously reported, but there was a correlation between lipophilicity and metabolic alteration of araC derivatives (r=0.99, n=5). 相似文献
45.
Incidence and mechanisms of aminoglycoside resistance inPseudomonas aeruginosa serotype O11 isolates
M. Kettner Ph. D. Sc. D. J. Kallová Ph. D. M. Hletková P. Milošovič M. D. 《Infection》1995,23(6):380-383
Summary Mechanisms of resistance to five aminoglycoside antibiotics: gentamicin (G), tobramycin (T), netilmicin (N), amikacin (A) and isepamicin (I), were assessed in 16 clinical isolates ofPseudomonas aeruginosa serotype O11, originating from five hospitals in Bratislava. All isolates werein vitro highly resistant to all mentioned aminoglycoside antibiotics (MIC>32 mg/l). Thirteen isolates produced three aminoglycoside-modifying enzymes (AGME), responsible for resistance to the respective aminoglycosides: AAC(6)-I (T, N, A); APH (2) (G, T); APH (3)-VI (I). In addition to this, in four isolates a production of AAC(3)-II (G, T, N) was observed. In three isolates no production of AGME was observed. The strains studied were isolated mainly from urine. Several isolates were able to transfer aminoglycoside resistance by bacterial conjugation toP. aeruginosa 1008 rifr recipient. The transconjugants from these transfers expressed the same resistance pattern and nearly the same mechanisms of resistance as the donor strains.
Inzidenz und Mechanismus der Aminoglykosid-Resistenz beiPseudomonas aeruginosa O11-Isolaten
Zusammenfassung Bei 16 klinischen Isolaten vonPseudomonas aeruginosa Serotyp O11 aus fünf Krankenhäusern in Bratislava wurde der Mechanismus der Resistenz gegen fünf Aminoglykosid-Antibiotika untersucht; Gentamicin (G), Tobramycin (T), Netilmicin (N), Amikacin (A) und Isepamicin (I). Alle Isolate warenin vitro hochresistent gegen alle genannten Aminoglykosid-Antibiotika (MHK-Werte >32 mg/l). 13 der Isolate bildeten drei Aminoglykosid-modifizierende Enzyme (AGME), die für die Resistenz gegenüber den entsprechenden Aminoglykosiden verantwortlich waren: AAC(6)-I (TNA): APH (2) (G, T): APH (3)-VI (I). Zusätzlich wurde bei drei Isolaten die Produktion von AAC(3)-II (G, T. N) beobachtet. In drei Isolaten fand sich keine Produktion von AGME. Die untersuchten Stämme waren überwiegend aus Urin isoliert worden. Mehrere der Isolate waren fähig, die Aminoglykosid-Resistenz durch bakterielle Konjugation auf denP. aeruginosa 1008 rifr Rezipienten zu übertragen. Die Transkonjugate von diesen Übertragungen exprimierten dasselbe Resistenzmuster und wiesen nahezu denselben Resistenzmechanismus auf wie die Spenderstämme.相似文献
46.
Ariano RE Demianczuk RH Danzinger RG Richard A Milan H Jamieson B 《The Canadian journal of hospital pharmacy》1995,48(5):284-289
A one-year pilot project was performed to assess the economic and clinical benefit of pharmacist involvement on the surgical wards of a 600-bed tertiary care, teaching hospital. A total of 405 recommendations were collected with a physician acceptance rate of 90%. From these recommendations, 1416 patient follow-ups were performed to document outcome. The total documented cost avoidance of the pharmacists' activities was $33,265.58. The total annual drug expenditure for the department of surgery declined by $59,662 representing a 9% decrease over the previous year with the greatest decline involving antimicrobials which decreased by $52,587 compared with the previous year. Most of the cost-avoidance in this area was attributable to antimicrobial selection and dosing adjustment in renal impairment. Pharmacist-directed pharmacokinetic monitoring of aminoglycosides resulted in a clinical success rate of 93.8% for treatment regimens and a 6.2% incidence of nephrotoxicity. Housestaff education aimed at improving prescribing practices were identified and provided for select agents including midazolam, ketorolac, vancomycin and aminoglycosides. As well, select recommendations were documented which illustrated the benefit to patient care of pharmacist involvement. Pharmacist involvement on the surgery services produced both financial and clinical benefits. 相似文献
47.
Milan Slavik P. Y. Liu Eric H. Kraut Ronald B. Natale Lawrence E. Flaherty Vernon K. Sondak 《Investigational new drugs》1995,13(2):143-147
Merbarone, NSC 336628, is an investigational anticancer drug with activity against experimental animal tumors including melanoma. This paper presents results of a Phase II clinical study of merbarone in patients with biopsy proven stage IV malignant melanoma without prior chemotherapy and with no evidence of CNS involvement. Thirty-five patients with median age 58 (range 27–81), with performance status 0–2 were treated with merbarone 1000 mg/m2/day for five days by intravenous continuous infusion repeated every 3 weeks. All patients (21 males and 14 females) were evaluable for toxicity. Two patients were not evaluable for response having been removed from protocol treatment due to toxicity and received other treatment during the first course of chemotherapy. Among the evaluable patients there was one complete response in a supraclavicular lymph node lasting four months and one partial liver response lasting three months. The remaining thirty-one patients were non-reponders. Of these one had a stable disease lasting 21 months. The overall objective response rate was 6% (2/35) with a 95% confidence interval of 1%–19%. Twenty-six of the 35 patients have died. The estimated median survival of the entire group was 9 months with a 95% confidence interval of six to eleven months. Renal toxicity was dose-limiting and manifested as increasing serum creatinine (54% of patients), proteinuria (51%) and hematuria (9%). One patient experienced grade 4 creatinine increase, proteinuria and acute renal failure. Other toxicities included nausea (71%), vomiting (51%), malaise (23%), weakness (20%), alopecia (17%), diarrhea (17%), anorexia (14%), transaminase (SGOT, SGPT) increase (14%), constipation (14%), alkaline phosphatase or 5nucleotidase increase (9%), and fever (9%). Hematologictoxicity (granulocytopenia, leukopenia, and anemia) was generally mild and infrequent (29%, only one patient had grade 4 granulocytopenia). Overall 9 patients (26%) had at least one grade 3 toxicity. We conclude that merbarone at this dose and schedule has detectable but minimal activity in the treatment of metastatic malignant melanoma and given the significant renal toxicity this schedule does not merit further evaluation in this disease. 相似文献
48.
Dentine phosphoproteins have been proposed to have an important role in mineralization. This study focused on the influence
of fluoride on the biochemical composition of dentine phosphoproteins and attempts to relate changes to the altered mineralization
witnessed during fluorosis. Wistar rats were rendered fluorotic by the administration of 20 ppm sodium fluoride in their drinking
water ad libitum, a nonfluorotic group received double-distilled, deionized water only. After 17 weeks, the teeth showed signs of fluorosis.
The incisors were removed, split longitudinally, and the pulps were removed. Teeth were powdered and demineralized in 10%
EDTA with protease inhibitors, after which the organic matrix was extracted with 4 M guanidinium chloride. Phosphoproteins
were selectively precipitated from the soluble extract by the addition of 1.0 M calcium chloride and further purified by anion
exchange chromatography. SDS-PAGE revealed two protein bands with molecular weights of 130 kDa and 66 kDa in the nonfluorotic
fraction and 116 kDa and 66 kDa in the fluorotic fraction. Western blotting analysis identified the 66 kDa band as α2-HS glycoprotein which co-precipitated with phosphoproteins. Electroelution of the protein bands was performed with subsequent
biochemical analyses. Phosphate content was determined for each protein band and was detectable in the 116 kDa and 130 kDa
bands from the fluorotic and nonfluorotic samples, respectively, with a decreased level noted in the 116 kDa band. The presence
of phosphate and the amino acid analysis of these bands suggested their identity to be dentine phosphoproteins. No changes
in the ratio of amino acids was detected in fluorotic samples. The fluoride-induced alterations to the biochemical structure
of dentine phosphoproteins would appear to influence the phosphorylation of these macromolecules only, possibly affecting
posttranslational events. Such alterations may play a role in disrupting the patterns of mineralization seen during fluorosis.
Received: 14 November 1997 / Accepted: 9 July 1998 相似文献
49.
Milo E 《EDTNA/ERCA journal (English ed.)》1996,22(3):41-42
Occupational therapy is defined by the American Occupational Therapy Association as: the art and science of directing man's participation in selected tasks, to restore, reinforce and enhance performance, facilitate learning of those skills and functions essential for adaptation and productivity, diminish or correct pathology and maintain health. 相似文献
50.
Kristl Julijana Pečar Slavko Šmid-Korbar Jelka Schara Milan 《Pharmaceutical research》1991,8(4):505-507
The effects of a polymer, the Li-salt copolymer of methyl-methacrylic acid, and its methyl ester on the motion of drug molecules in hydrocolloids were studied. The investigation was carried out by means of electron paramagnetic resonance (EPR) using the model nitroxide tempol, and the spin-labeled drugs lidocaine (si-lid) and dexamethasone (sl-dex). Synthesis of sl-dex was performed. Spin-labeled molecules dissolved in hydrocolloids undergo a fast reorientation motion. The decreasing order of rotational correlation times () —sl-dex > si-lid > tempol—suggests that the size and the shape of the molecules strongly affect their motion. The inhibition of motion of larger molecules depends also on their flexibility. The values indicate proportionality of the microviscosity of hydrocolloids to the polymer concentration. Rotational motion is dependent on the local environment conditioned by the free spaces between polymer molecules. 相似文献