全文获取类型
收费全文 | 5927篇 |
免费 | 428篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 192篇 |
妇产科学 | 138篇 |
基础医学 | 835篇 |
口腔科学 | 94篇 |
临床医学 | 592篇 |
内科学 | 1348篇 |
皮肤病学 | 131篇 |
神经病学 | 364篇 |
特种医学 | 188篇 |
外科学 | 821篇 |
综合类 | 65篇 |
预防医学 | 597篇 |
眼科学 | 122篇 |
药学 | 488篇 |
中国医学 | 25篇 |
肿瘤学 | 349篇 |
出版年
2023年 | 43篇 |
2022年 | 56篇 |
2021年 | 141篇 |
2020年 | 86篇 |
2019年 | 136篇 |
2018年 | 129篇 |
2017年 | 128篇 |
2016年 | 125篇 |
2015年 | 176篇 |
2014年 | 202篇 |
2013年 | 244篇 |
2012年 | 372篇 |
2011年 | 395篇 |
2010年 | 197篇 |
2009年 | 211篇 |
2008年 | 386篇 |
2007年 | 430篇 |
2006年 | 363篇 |
2005年 | 329篇 |
2004年 | 346篇 |
2003年 | 304篇 |
2002年 | 269篇 |
2001年 | 133篇 |
2000年 | 152篇 |
1999年 | 128篇 |
1998年 | 57篇 |
1997年 | 36篇 |
1996年 | 39篇 |
1995年 | 34篇 |
1994年 | 33篇 |
1993年 | 43篇 |
1992年 | 67篇 |
1991年 | 58篇 |
1990年 | 71篇 |
1989年 | 60篇 |
1988年 | 47篇 |
1987年 | 52篇 |
1986年 | 51篇 |
1985年 | 39篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1979年 | 28篇 |
1978年 | 18篇 |
1976年 | 15篇 |
1975年 | 13篇 |
1974年 | 13篇 |
1973年 | 17篇 |
1972年 | 12篇 |
排序方式: 共有6426条查询结果,搜索用时 0 毫秒
1.
Edyta C Pirog Rebecca N Baergen Robert A Soslow Diane Tam Amy E DeMattia Yao-Tseng Chen Christina Isacson 《The American journal of surgical pathology》2002,26(1):70-75
There is considerable interobserver variation in the diagnosis of low-grade squamous intraepithelial lesion that involves mature squamous epithelium. Our aim was to evaluate the utility of MIB-1 immunostaining as an adjunct test to increase diagnostic accuracy. Consecutive cervical biopsies originally diagnosed as normal (n = 26) or low-grade squamous intraepithelial lesion (n = 23) were reviewed by three pathologists to obtain a consensus diagnosis. MIB-1 immunostaining was performed, and positive staining was defined as a cluster of at least two stained nuclei in the upper two thirds of the epithelial thickness. Human papillomavirus (HPV) DNA detection was performed using a polymerase chain reaction assay. All cases were subsequently reclassified as low-grade squamous intraepithelial lesion (LSIL) or normal (NL) when two or three of three gold standard criteria were satisfied (LSIL gold standard criteria = consensus diagnosis of LSIL, HPV+, MIB-1+; NL gold standard criteria = consensus diagnosis of NL, HPV-, MIB-1-). Using the gold standard diagnoses, we have identified that 14 normal cases (36%) were originally overdiagnosed as LSIL, and one LSIL case (10%) was originally underdiagnosed as normal. All MIB-1-positive cases were HPV+ and identified as LSIL in the consensus review. All MIB-1-negative cases were NL by gold standard criteria. The sensitivity (1.0) and the specificity (1.0) of MIB-1 staining for identifying LSIL were superior to the sensitivity (0.9) and the specificity (0.8) of HPV testing. In conclusion, MIB-1 is a highly sensitive and specific marker for identifying low-grade squamous intraepithelial lesion and is helpful in verifying the diagnosis of equivocal cases. 相似文献
2.
3.
William P. Grant DPM Laurence G. Rubin DPM Guy R. Pupp DPM George Vito DPM Dwayne Jacobus DPM Erin A. Jerlin DPM Harry S. Tam DPM 《The Journal of foot and ankle surgery》2007,46(5):325-335
The purpose of this study was to assess 7 methods of fixation for a midtarsal osteotomy. Polyurethane foam models (N = 6) and cadaver specimens (N = 4-7) were used to examine the force generated by the different constructs of fixation. A midtarsal osteotomy was performed on each specimen in the test groups. The osteotomies were fixated either with 2 parallel 0.062-in Kirschner wires and 40-mm-long, 4-mm partially threaded, cancellous, cannulated titanium screws, an external ring fixator (frame), a frame with wires tensioned (tension), a frame with wires tensioned and compressed toward the osteotomy (tension and compression), a frame with tension, compression, and parallel Kirschner wires, or a frame with tension, compression, and two 4.0 cannulated parallel screws, respectively. Each model was fixated, and the force generated by the construct across the osteotomy was recorded via the use of pressure-sensitive film. Statistical analysis of the data in the polyurethane foam group determined that the use of frame with tension, compression, and two 4.0 parallel cannulated screws was statistically superior to 1) frame, 2) frame with tension, 3) 2 parallel Kirschner wires, 4) two 4.0 cannulated parallel screws, and 5) frame with tension and compression. A cadaver study determined that the frame with tension, compression, and 2 parallel Kirschner wires was statistically superior to 1) frame and 2) two parallel Kirschner wires. These findings suggest that there is a difference in the force generated by the type of fixation construct across a midtarsal osteotomy. 相似文献
4.
Knife injuries can be classified into stabbing injuries and multiple laceration or multiple chops, the latter being much more common in Chinese communities. It is the mark of criminal gang attacks with their tendency to use long knives and choppers rather than guns. The intention is often to wound rather than kill. A survey of 89 cases revealed that 90% of the victims are men, with a mean age of 27 years; 75% was admitted to the hospital at night, and in 78% of the cases the assailants were persons unknown, or so we were told by the victims. The reasons for the attacks were also not given. Most of the women victims were assaulted by their spouse. Some 74% of the patients suffered three to six lacerations; 62% of the injuries were on the extensor surfaces of the upper limbs, while the hand and the back of the trunk were also common sites. The type of management differs from that for stabbing injuries. There were no fatalities, and less than half of the patients required blood transfusion. The average hospital stay was 6.2 days. The morbidity of these injuries involves damaged tendons and nerves. 相似文献
5.
P Horhant J M N'Guyen Van Tam J P Letoquart M Pompilio Y Haffaf J Chaperon A Mambrini 《Journal de chirurgie》1990,127(8-9):392-395
Sixty nine patients over 75 years old who had a colectomy were retrospectively studied. The carcinoma of the colon represented the main indication for 42 cases (60.9%) and 22 patients (31.9%) were immediately operated. The influence of parameters such as age, sex, visceral defects, emergency, performance of a colostomy or associated intervention, type of colic pathology, was statistically studied. The age (p less than 0.05), emergency (p less than 0.03) and the number of defects greater than or equal to 3 (p less than 0.04) contribute to mortality. The number of defects greater than or equal to 3 (p less than 0.006) contributes to general morbidity. Only complications connected with the operation by itself significantly prolong the duration of hospitalization (p less than 0.02). The authors draw the conclusion that the age by itself is not a contra-indication for operation except in case of associated polyvisceral failure. In addition, it is required to carry out an early detection of colic lesions in elderly subjects in order to contemplate surgery before complications whose prognosis is fearsome (54.5% of death in emergency operation). 相似文献
6.
Keita Mayanagi Tamás Gáspár Prasad V G Katakam Béla Kis David W Busija 《Journal of cerebral blood flow and metabolism》2007,27(2):348-355
Activation of mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels protects the brain against ischemic or chemical challenge. Unfortunately, the prototype mitoK(ATP) channel opener, diazoxide, has mitoK(ATP) channel-independent actions. We examined the effects of BMS-191095, a novel selective mitoK(ATP) channel opener, on transient ischemia induced by middle cerebral artery occlusion (MCAO) in rats. Male Wister rats were subjected to 90 mins of MCAO. BMS-191095 (25 microg; estimated brain concentration of 40 micromol/L) or vehicle was infused intraventricularly before the onset of ischemia. In addition, the effects of BMS-191095 on plasma and mitochondrial membrane potentials and reactive oxygen species (ROS) production in cultured neurons were examined. Finally, we determined the effects of BMS-191095 on cerebral blood flow (CBF) and potassium currents in cerebrovascular myocytes. Treatment with BMS-191095 24 h before the onset of ischemia reduced total infarct volume by 32% and cortical infarct volume by 38%. However, BMS-191095 administered 30 or 60 mins before MCAO had no effect. The protective effects of BMS-191095 were prevented by co-treatment with 5-hydroxydecanoate (5-HD), a mitoK(ATP) channel antagonist. In cultured neurons, BMS-191095 (40 micromol/L) depolarized the mitochondria without affecting ROS levels, and this effect was inhibited by 5-HD. BMS-191095, similar to the vehicle, caused an unexplained but modest reduction in the CBF. Importantly, BMS-191095 did not affect either the potassium currents in cerebrovascular myocytes or the plasma membrane potential of neurons. Thus, BMS-191095 afforded protection against cerebral ischemia by delayed preconditioning via selective opening of mitoK(ATP) channels and without ROS generation. 相似文献
7.
8.
Prevalence of antibody to human T-cell lymphotropic virus type I/II in people of Caribbean origin in Toronto. 下载免费PDF全文
J Chiavetta J Nusbacher F Tam A Wall J Steaffens H Lee 《Canadian Medical Association journal》1992,147(10):1493-1498
OBJECTIVE: To estimate the prevalence of antibody to human T-cell lymphotropic virus type I/II (anti-HTLV-I/II) in people from an HTLV-I/II-endemic area (the Caribbean) living in a nonendemic region (Canada). DESIGN: Cross-sectional household survey. SETTING: Households in Toronto in 1989. PARTICIPANTS: A modified quota sampling method was used to recruit subjects of Caribbean origin as well as other Canadians. Of 2900 people invited to participate in the study 1323, 743 of Caribbean origin, were interviewed about their background and possible exposure to HTLV-I/II. MAIN OUTCOME MEASURES: Blood samples were analysed for anti-HTLV-I/II by means of an enzyme-linked immunoassay, the result being confirmed by the Western blot technique and radioimmunoprecipitation assay. The samples were also analysed for antibody to human immunodeficiency virus (anti-HIV) and hepatitis B surface antigen (HBsAg) and for surrogate markers of non-A, non-B hepatitis. RESULTS: A total of 853 blood samples (64.5%) were analysed, 483 (56.6%) from subjects of Caribbean origin. The proportion of subjects who agreed to give a blood sample was similar for the Caribbean and non-Caribbean strata. Eleven subjects, all of Caribbean origin (2.3% of the Caribbean stratum), were confirmed to be positive for anti-HTLV-I/II. There were no significant differences between the antibody-positive and antibody-negative subjects with respect to sex, age, racial origin or residence in the Caribbean for at least 22 years. All anti-HTLV-I/II-positive subjects were negative for anti-HIV and HBsAg, and four (36.4%) were positive for antibody to HBsAg and to hepatitis B core antigen. CONCLUSIONS: Except for origin, an association between antibody positivity and other factors could not be demonstrated. The findings suggest that blood donor screening might include place of origin in addition to the usual lifestyle or behavioural factors. However, the need to ensure safety of transfusion must be balanced against the need for participation of all groups in the blood transfusion program. 相似文献
9.
László Bajnok Bertalan Kozlovszky József Varga Judit Antalffy Sándor Olvasztó Tamás Fülöp Jr. 《European journal of nuclear medicine and molecular imaging》1994,21(12):1326-1332
Technetium-99m sestamibi was used for functional investigation of the muscle perfusion of lower extremities in 35 patients
with peripheral vascular disease. The aim was to test what useful information could be obtained by additional imaging of the
legs in patients referred for risk stratification with dipyridamole myocardial scanning. Posterior images were acquired over
the thighs and calves after postocclusive reactive hyperaemia and at rest. Inter- and intraextremity ratios and differences
between the stress and rest data were used for the assessment of abnormal circulation. Arteriography was performed in every
case, and surgical procedures or transluminal angioplasty in 31 patients. To estimate diagnostic accuracy, the results of99mTc-sestamibi scintigraphy were compared with those of angiography and the functional consequences of revascularization procedures.
The sensitivity and specificity of99mTc-sestamibi scintigraphy were 55% and 25%, respectively, with an overall accuracy of 50%. Apparently methodological error
was not responsible for these poor results. Instead, a paradoxically high uptake of the radiopharmaceutical in muscles supplied
by significantly stenosed vessels was identified as the main source of both false-negative and false-positive results. This
phenomenon resembles the findings of a previous study involving delayed administration of thallium-201 after exercise. In
conclusion,99mTc-sestamibi scintigraphy has not proved sufficiently reliable to help in the management strategy for patients with peripheral
vascular disease. 相似文献
10.
CA von Arnim R Spoelgen ID Peltan M Deng S Courchesne M Koker T Matsui H Kowa SF Lichtenthaler MC Irizarry BT Hyman 《The Journal of neuroscience》2006,26(39):9913-9922
The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD. 相似文献