全文获取类型
收费全文 | 18532篇 |
免费 | 1172篇 |
国内免费 | 599篇 |
专业分类
耳鼻咽喉 | 292篇 |
儿科学 | 100篇 |
妇产科学 | 240篇 |
基础医学 | 620篇 |
口腔科学 | 278篇 |
临床医学 | 1533篇 |
内科学 | 2984篇 |
皮肤病学 | 126篇 |
神经病学 | 495篇 |
特种医学 | 392篇 |
外国民族医学 | 4篇 |
外科学 | 6060篇 |
综合类 | 2503篇 |
预防医学 | 661篇 |
眼科学 | 194篇 |
药学 | 1109篇 |
28篇 | |
中国医学 | 158篇 |
肿瘤学 | 2526篇 |
出版年
2024年 | 45篇 |
2023年 | 383篇 |
2022年 | 693篇 |
2021年 | 889篇 |
2020年 | 788篇 |
2019年 | 674篇 |
2018年 | 643篇 |
2017年 | 646篇 |
2016年 | 751篇 |
2015年 | 704篇 |
2014年 | 1467篇 |
2013年 | 1238篇 |
2012年 | 1119篇 |
2011年 | 1255篇 |
2010年 | 977篇 |
2009年 | 967篇 |
2008年 | 944篇 |
2007年 | 913篇 |
2006年 | 762篇 |
2005年 | 661篇 |
2004年 | 538篇 |
2003年 | 418篇 |
2002年 | 348篇 |
2001年 | 300篇 |
2000年 | 231篇 |
1999年 | 242篇 |
1998年 | 196篇 |
1997年 | 174篇 |
1996年 | 161篇 |
1995年 | 146篇 |
1994年 | 152篇 |
1993年 | 96篇 |
1992年 | 76篇 |
1991年 | 76篇 |
1990年 | 58篇 |
1989年 | 58篇 |
1988年 | 49篇 |
1987年 | 51篇 |
1986年 | 66篇 |
1985年 | 55篇 |
1984年 | 64篇 |
1983年 | 24篇 |
1982年 | 42篇 |
1981年 | 29篇 |
1980年 | 30篇 |
1979年 | 24篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 10篇 |
1973年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
D. L. O'Donoghue G. A. Bishop 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1990,80(1):63-71
Summary Purkinje cells in zones a and b of the vermis and zone c in the intermediate cortex of the anterior lobe were intracellularly injected with horseradish peroxidase and the distribution patterns of the varicosities present on their axonal collaterals were quantified and compared at the light microscopic level. The data derived from this study reveal that each individual axonal arbor had a unique pattern of distribution. However, certain principles of distribution could be applied to the collaterals regardless of the cortical location of the parent cell, including the following: 1) the total number of varicosities derived from the axonal collaterals of individual Purkinje cells is relatively uniform; 2) the collateral plexi have a greater extent in the sagittal plane as compared to the transverse plane; 3) the majority of varicosities remain within 200–300 m of the parent cell in both the sagittal and transverse planes; 4) there is a heterogenous distribution of varicosities within the area traversed by the axonal branches; and 5) the majority of varicosities are located within the Purkinje cell layer. Although there were similarities in the pattern of distribution for collaterals, there were also variations which distinguished the plexi in the three zones. The collaterals of zone a cells tended to be the most confined in both the sagittal and transverse planes. In contrast, several cells in zone b and c had branches that extended for relatively long distances in the sagittal plane. In zone b the collaterals have an asymmetric distribution around the cell of origin in the transverse plane. In zones a and c there is a tendency for a more symmetric pattern of distribution in this plane. The similarities in the number and laminar distribution of varicosities, as well as the predominantly sagittal orientation of the collaterals in all zones of the cerebellar cortex suggest that the collaterals subserve a common function throughout the cerebellar cortex. However, variations indicate that there may be subtle differences in the way recurrent collaterals process information in the cerebellar cortex that may be related to the functional heterogeneity or the location of the targets of the collaterals in the three zones analyzed. 相似文献
32.
Plädoyer für die primäre Resektion mit primärer Anastomose bei der komplizierten Sigmadiverticulitis
J. Wedell G. Banzhaf A. Mrohs R. Fischer 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1989,374(5):259-266
Zusammenfassung Von 1973 bis 1986 wurden 107 Patienten mit einer komplizierten Sigmadiverticulitis operiert. Es handelte sich um 47 Frauen und 60 Männer bei einem Durchschnittsalter von 62 Jahren. Von 107 Patienten wiesen 14 eine perforierte Diverticulitis mit diffuser eitriger/kotiger Peritonitis auf, 68 Patienten eine perforierte Diverticulitis mit lokalisierter eitriger Peritonitis/paracolischem Absceß und 25 Patienten eine akute phlegmonöse Diverticulitis ohne Perforation. Zusätzliche pathologische Befunde waren: innere Fisteln (13 Patienten), nekrotisierende Fasciitis (3 Patienten), Stenose mit Ileus (3 Patienten) und synchrone Carcinome (7 Patienten). Die Gesamtletalität der 107 Patienten betrug 9,3% (=10 Patienten), die Morbidität der 97 überlebenden Patienten 34,0% (= 33 Patienten). Die Letalität bei 14 Patienten mit perforierter Diverticulitis und diffuser eitriger/kotiger Peritonitis lag bei 50%, die der 68 Patienten mit perforierter Diverticulitis und lokaler eitriger Peritonitis/ paracolischem Absceß bei 4,4%, die der 25 Patienten mit akuter phlegmonöser Diverticulitis ohne Perforation bei 0%. Von den 10 Patienten verstarben 7 bei Operation ihrer perforierten Diverticulitis mit diffuser eitriger Peritonitis, 1 (5) nach primärer Resektion mit primärer Anastomose, 3 (5) nach Operation nach Hartmann, 3 (4) nach alleiniger Anlage einer Colostomie. Bei Operation der perforierten Diverticulitis mit lokaler Peritonitis verstarben 3 Patienten, 2 (6) nach Operation nach Hartman und 1 (5) nach alleiniger Anlage einer Colostomie. Trotz einer hohen Zunahme der Zahl primärer Resektionen mit primärer Anasto mose im Zeitraum 1980–1986 ergab sich im Vergleich zum 7-Jahresabschnitt 1973–1979 ein Rückgang der Letalität von 35,7% auf 0% bei dieser Operation. Ihre Anwendung ist auch gerechtfertigt bei der perforierten Diverticulitis mit lokaler wie diffus eitriger oder kotiger Peritonitis.
Primary resection with primary anastomosis in complicated diverticulitis of the sigma
Summary Of the 107 patients with complicated diverticulitis operated from 1973–1986 47 were females and 60 males. In 14 of the 107 patients a perforated diverticulitis with diffuse purulent/faecal peritonitis was found, a perforated diverticulitis with localized purulent peritonitis/paracolic abscess in 68 patients and an acute phlegmonous diverticulitis without perforation in 25 patients. Additional pathologic findings were internal fistulae (13 patients), necrotizing fasciitis (3 patients), obstruction (3 patients) and synchronous carcinoma (7 patients). The overall mortality of the 107 patients was 9.3 % (=10 patients) and the morbidity of the 97 survivors 34% (=33 patients). The mortality of the 1.4 patients with perforated diverticulitis and diffuse purulent peritonitis was 50%, of the 68 patients with perforated diverticulitis and localized purulent peritonitis 4.4% and of the 25 patients with acute phlegmonous diverticulitis 0%. Seven of the 10 patients died after operation of the perforated diverticulitis with diffuse purulent peritonitis — 1 (5) after primary resection with primary anastomosis, 3 (5) after Hartmann procedure, 3 (4) after loop colostomy alone. Three patients died after operation of the perforated diverticulitis with localized purulent peritonitis — 2 (6) after Hartmann procedure, 1 (5) after loop colostomy alone. In spite of forcing the primary resection with primary anastomosis in the years from 1980–1986 the mortality decreased for these operations from 35.7% in 1973–1979 to 0% in 1980–1986. The indication of primary resection with primary anas tomosis is justified also for perforated diverticulitis with localized and diffuse peritonitis.
Auszugsweise vorgetragen auf dem Symposium Entzündliche Darmerkrankungen der Medizinischen Akademie Carl Gustav Carus, Dresden, 20. November 1987 相似文献
33.
Although anaphylactoid reactions to local anesthetics are well known, a radioallergosorbent test (RAST) to detect specific drug reagin (IgE) anti-body has not been developed. We established RAST for local anesthetics by using carboxylic acid derivatives of lidocaine, procaine and methylparaben. Serum samples were taken from 100 volunteers who were regarded to be nonallergic to the drugs used. Negative RAST values obtained from these volunteers were 1653 ± 254(SD) cpm (lidocaine), 2750 ± 264cpm (procaine), and 2805 ± 336cpm (methyl paraben).(Kokubu M, Oda K, Shinya N: Radioallergosorbent test (RAST) for specific IgE antibody to lidocaine, procaine and methylparaben. J Anesth 3: 74–79, 1989) 相似文献
34.
35.
36.
Hisaeda HO Shinohara M Kouzaki M Fukunaga T 《European journal of applied physiology》2001,86(1):17-23
The effects of the local blood circulation and absolute torque on muscle endurance at different knee-joint angles were determined.
The rate of muscle deoxygenation (using near-infrared spectroscopy), and the rate of muscle fatigue (using the slope of integrated
electromyography, iEMG) were evaluated concurrently. Nine healthy subjects performed submaximal (50% maximal voluntary contraction,
MVC) static knee extension at 50° (extended position, EXT) and 90° (flexed position, FLEX) joint angles until the target torque
could no longer be maintained: that time was measured as the endurance time. They exercised with the circulation occluded
(OCCL), and without (FREE) to study the possible effects of the local circulation. Although MVC torque was independent of
joint angle [mean (SD) FLEX 250.6 (51.7) N·m and EXT 246.5 (46.6) N·m], significantly shorter (P<0.01) endurance time in FLEX [FREE 71.1 (10) s and OCCL 63.1 (8.8) s] than at EXT [FREE 115.3 (30) s and OCCL 106.7 (29.1) s]
were obtained in both circulatory conditions. The iEMG-time slope was significantly greater in FLEX at the proximal and distal
portion (P<0.05) in both circulatory conditions. Muscle deoxygenation rate in OCCL was significantly greater (P<0.05) at FLEX [20.8 (8.0)%] than EXT [10.9 (4.0)%]. The results would suggest that different knee-joint angle affects muscle
endurance even if the local circulation is controlled. Circulatory disturbance would further reduce muscle endurance in EXT,
but not in FLEX. Because of the greater muscle internal force in FLEX, local blood flow might be already limited even with
a free circulation. The greater muscle deoxygenation and muscle fatigability would be related to the shorter muscle endurance
in FLEX.
Electronic Publication 相似文献
37.
Kozo Hirata Tetsuo Nagasaka Tadahiro Nunomura Michel Cabanac 《European journal of applied physiology》1988,58(1-2):92-96
Summary The effects of local heating on finger blood flow (BF) and local thermal sensation (Sens
w
) were studied. Finger BFs in both hands were measured simultaneously; one hand was immersed in water the temperature (T
w
) of which was raised from 35° C to 43°C by steps of 2° C every 10 min, while the other hand was kept atT
w
35°C. FingerBF in the locally heated hand decreased atT
w
37 to 41°C, while fingerBF in the control hand did not alter. Sensw, in the heated hand showed a dynamic response, initially increasing concomitantly with an increase inT
w
, then gradually returning and adapting to a new level of Sensw. The dynamic response of Sensw, was not perceived during mental calculation even whenT
w
was raised to 40°C, and the reduction in finger blood flow was not observed. These results suggest that finger vasoconstriction caused by local heating closely relates to the dynamic response characteristic of local thermal sensation atT
w
above core temperature, and that the perception of local thermal sensation in the central nervous system is involved in the mechanism of this vasoconstrictor response. 相似文献
38.
Yutaka Endo Jun -Ichi Nishimura Fukuko Kimura 《Pflügers Archiv : European journal of physiology》1994,426(3-4):183-188
The present study examined the effect of glucocorticoid manipulations on local cerebral blood flow in the hippocampus. We measured local cerebral blood flow in the hippocampus at 1-h intervals over a 1-day period in freely moving rats, by means of the H2 clearance method, before and after sham adrenalectomy, adrenalectomy or adrenalectomy with corticosterone replacement. We also measured local cerebral blood flow in the prefrontal cortex before and after adrenalectomy. Four weeks after the adrenalectomy, hippocampal blood flow at each time of day was an average of 47% greater than before the operation, showing diurnal variation as before. After the sham adrenalectomy or adrenalectomy with corticosterone replacement, hippocampal blood flow did not change significantly with respect to either its level or its diurnal variation. Local cerebral blood flow in the prefrontal cortex increased by only 19% after adrenalectomy. The present study demonstrates that adrenalectomy causes a remarkable increase in hippocampal blood flow, probably due to a lack of corticosterone. 相似文献
39.
F. Lasbennes J. Seylaz 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1986,63(1):169-172
Summary The cerebrovascular consequences of the gentle restraint commonly used for the measurement of local cerebral blood flow (LCBF) in conscious rats has been tested by using two drugs, propranolol and diazepam. Propranolol induced small LCBF decreases in 7 structures suggesting that the cerebral circulation was partially controlled by the activation of intra or extracerebral aminergic pathways in this protocol. Sedative doses of diazepam reduced LCBF in most of the structures but anxiolytic doses increased it in 4 structures. This effect may be due to a regionally differentiated modification of activity in the brain due to the selective inhibition of limbic structures by diazepam. Since propranolol and diazepam induced only small changes, the LCBF of gently restrained rats appeared to be minimally affected by the stressful situation imposed by the protocol. 相似文献
40.
Hull MA Fenwick SW Chapple KS Scott N Toogood GJ Lodge JP 《Clinical & experimental metastasis》2000,18(1):21-27
Cyclooxygenase-2 (COX-2) is up-regulated in 85-90% of primary human colorectal cancers and is a putative target for the chemopreventative activity of non-steroidal anti-inflammatory drugs. However, COX-2 expression by human colorectal cancer liver metastases has been poorly characterized. We studied a consecutive series of 38 patients who underwent liver resection for metastatic disease, for whom long-term (up to 57 months), prospective follow-up data were available. Semi-quantitative immunohistochemistry for COX-2 was performed on 54 metastases from 35 patients, for whom adequate histological material was available. Diffuse cytoplasmic staining for COX-2 protein was detected in cancer cells in 100% of metastases (COX-2 score 1, n=25; score 2, n=29). There was no relationship between metastasis size or differentiation grade and the level of COX-2 protein expression. There was no difference in colorectal cancer-free or overall survival between patients with high (score 2) and low (score 1) COX-2 scores (Kaplan–Meier survival analysis and log rank test, both P=0.97). Multivariate Cox regression analysis identified age, incomplete resection and presence of extra-hepatic disease as independent predictors of disease-free and overall survival following surgery. COX-2 protein was also localized to a subset of stromal fibroblasts and mononuclear cells within metastases as well as hepatocytes from resection specimens. COX-2 protein was expressed by cancer cells in all human colorectal cancer liver metastases which were studied. Investigation of the effect of selective COX-2 inhibition on metastasis growth and metastasis cancer cell proliferation/apoptosis in vivo are warranted. 相似文献