全文获取类型
收费全文 | 11326篇 |
免费 | 540篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 151篇 |
儿科学 | 166篇 |
妇产科学 | 154篇 |
基础医学 | 1577篇 |
口腔科学 | 340篇 |
临床医学 | 723篇 |
内科学 | 2420篇 |
皮肤病学 | 116篇 |
神经病学 | 755篇 |
特种医学 | 973篇 |
外科学 | 1808篇 |
综合类 | 62篇 |
预防医学 | 283篇 |
眼科学 | 131篇 |
药学 | 927篇 |
中国医学 | 16篇 |
肿瘤学 | 1296篇 |
出版年
2022年 | 83篇 |
2021年 | 161篇 |
2020年 | 76篇 |
2019年 | 120篇 |
2018年 | 163篇 |
2017年 | 118篇 |
2016年 | 158篇 |
2015年 | 170篇 |
2014年 | 196篇 |
2013年 | 269篇 |
2012年 | 384篇 |
2011年 | 477篇 |
2010年 | 279篇 |
2009年 | 264篇 |
2008年 | 431篇 |
2007年 | 461篇 |
2006年 | 477篇 |
2005年 | 514篇 |
2004年 | 516篇 |
2003年 | 496篇 |
2002年 | 480篇 |
2001年 | 469篇 |
2000年 | 478篇 |
1999年 | 435篇 |
1998年 | 165篇 |
1997年 | 131篇 |
1996年 | 134篇 |
1995年 | 96篇 |
1994年 | 87篇 |
1993年 | 79篇 |
1992年 | 341篇 |
1991年 | 294篇 |
1990年 | 310篇 |
1989年 | 332篇 |
1988年 | 289篇 |
1987年 | 291篇 |
1986年 | 244篇 |
1985年 | 245篇 |
1984年 | 156篇 |
1983年 | 106篇 |
1982年 | 55篇 |
1981年 | 48篇 |
1979年 | 78篇 |
1978年 | 70篇 |
1977年 | 65篇 |
1976年 | 46篇 |
1974年 | 60篇 |
1972年 | 55篇 |
1970年 | 50篇 |
1968年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
We introduce a selective adiabatic pulse sequence suitable for generating selective spin-echoes for both MR imaging and spectroscopy. The technique is simple; one uses the echo generated by any pair of identical selective adiabatic inversion pulses. The nonlinear phase across the slice is compensated perfectly by the second pi pulse. This compensation is immune to RF inhomogeneity and nonlinearity. For imaging applications, we concentrate on a reduced-power version of the pulse sequence in which time is traded off variably for RF amplitude in the presence of a time-varying gradient. This technique, known as variable-rate excitation, mildly degrades the off-resonant slice profile when applied to amplitude-modulated pulses. We present theoretical explanations and experimental results that show that the variable-rate adiabatic pulses are immune to off-resonant degradation of the magnitude normally encountered in MR imaging. 相似文献
53.
Inappropriate secretion of antidiuretic hormone in isolated adrenocorticotropin deficiency. 总被引:1,自引:0,他引:1
H Wakui T Nishinari S Nishimura Y Endo Y Nakamoto A B Miura 《The American journal of the medical sciences》1991,301(5):319-321
A 62-year-old man was admitted because of nausea and vomiting. Severe hyponatremia with renal sodium loss was found. Endocrinological studies revealed that the patient had isolated adrenocorticotropin (ACTH) deficiency and secondary adrenocortical insufficiency. Furthermore, an inappropriate secretion of antidiuretic hormone (ADH) in relation to the low plasma osmolality was observed at an early stage of hyponatremia. Hydrocortisone therapy effectively corrected his hyponatremia. Following the correction of hyponatremia, the value of free water clearance increased and the level of the plasma ADH decreased. Thus, the present case indicates that ACTH deficiency can cause the syndrome of inappropriate secretion of ADH. 相似文献
54.
R N Nishimura B E Dwyer J de Vellis K B Clegg 《Brain research. Molecular brain research》1992,12(1-3):203-208
The heat shock response in a transformed astrocyte line was compared with nontransformed astrocytes. The synthesis of HSP 68, the major inducible heat shock protein (HSP 68) was induced by a non-lethal 45 degrees C, 10 min heat shock. Although the incorporation of [35S]methionine into HSP 68 suggested that similar amounts of protein were being synthesized after heat shock, Western immunoblotting demonstrated striking differences in the HSP immunostaining between the two cell types. By one- and 'two-dimensional gel electrophoresis the major 68 kDa heat shock protein (HSP 68) was similar in both cell types. However, HSP 68 from heat shocked, transformed astrocytes did not immunostain with the monoclonal antibody, C-92, which is specific for the major inducible heat shock protein of HeLa cells. In contrast HSP 68 from heat shocked, nontransformed astrocytes immunostained quite well. A polyclonal antibody raised against the inducible 72 kDa heat shock protein of HeLa cells immunostained the HSP 68 from both astrocytes and transformed astrocytes. Analysis of the mRNA from the two cell types after heat shock revealed two bands of approximately 2.5 and 2.8 kb in astrocytes but only a single 2.5 kb band in the heat shocked transformed astroglia. These results suggest that structural differences in the HSP 68 may be present in the transformed astrocytes compared to the normal astrocytes. 相似文献
55.
K Imataka H Sakamoto H Nishimura K Ieki J Fujii 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1992,29(6):503-508
The admission of antihypertensive medications in the elderly (65 y.o. or more, 269 pts) was compared to that in younger cases (less than 65 y.o., 348 pts). All were outpatients who visited our clinic in 1990. The number of patients on a single therapeutic regimen was almost equal in both age groups. Once-a-day regimens were more common in the young (56.9% vs 48.3%, p less than 0.05), and three times-a-day regimens were more common in the elderly (14.7% vs 23.1%, p less than 0.01). The choice of antihypertensive drugs in patients with single therapy or combined therapy in the young was beta blockers in 49.7%, Ca blockers in 39.4%, diuretics in 30.7% and ACE inhibitors in 17.8%, and those in the elderly were Ca blockers in 46.1%, diuretics in 44.2%, beta blockers in 33.8%, and ACE inhibitors in 16.4%. The patients were subdivided into three groups according to the time of the initial visit to the clinic; initial visit during 1969-1979 (phase 1), 1980-1984 (phase 2) and 1985-1990 (phase 3). In the young, choice of beta blockers and diuretics was most popular in phase 1. However, the choice of diuretics decreased in phase 2, and in phase 3 beta blockers were used in 50.4%, Ca blockers in 43.2%, ACE inhibitors in 22.3% and diuretics in only 17.3%. In the elderly, diuretics were most popular followed by Ca blockers and beta blockers in phase 1 and phase 2. In phase 3 Ca blockers were selected in 58.2% followed by both beta blockers and ACE inhibitors in 28.4% then diuretics in 23.9%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
56.
N. Hizawa M. Kawaguchi S.-K. Huang M. Nishimura 《Clinical and experimental allergy》2006,36(9):1109-1114
IL-17 family members belong to a distinct category of cytokines that coordinate local tissue inflammation by inducing the release of pro-inflammatory and neutrophil-mobilizing cytokines. The importance of the IL-17 family in inflammatory and autoimmune disease is becoming increasingly apparent. IL-17F is a recently discovered member of the IL-17 family that has a number of biological activities through induction of various cytokines, chemokines, and mediators. IL-17A, the founding member of the IL-17 family, and IL-17F are produced by several inflammatory cells, including activated T cells, in response to infectious and antigenic stimuli. Overexpression of IL-17A or IL-17F in the lungs results in induction of CXC chemokines and neutrophil recruitment. In a case-control study of 1125 unrelated Japanese subjects, a His161 to Arg161 (H161R) substitution in the third exon of the IL17F gene was shown to be associated with asthma and chronic obstructive pulmonary disease (COPD). Functionally, this variant failed to induce cytokines and chemokines, and interestingly, was able to antagonize the activity of wild-type IL-17F. These results provide an experimental basis for the observed genetic association with chronic inflammatory lung diseases, and also suggest the potential therapeutic utility of this antagonistic variant of IL-17F. Given that asthma and COPD are complex diseases involving a number of genetic and environmental factors, the genetic impact of IL-17F H161R with regard to the development of chronic airway inflammation likely varies among individuals with different genetic backgrounds and environmental exposures. 相似文献
57.
Satoshi Yoneda Yozo Kobayashi Takehiro Nunoi Kosuke Takeda Atsushi Matsumori Minoru Andoh Hirohisa Tsujinoue Kimio Nishimura Hiroshi Fukui 《Nihon Shokakibyo Gakkai zasshi》2006,103(11):1270-1273
A 23-year-old woman had lower abdominal pain, diarrhea and bloody stool was admitted and given a diagnosis of influenza B. Her home doctor had started treatment by neuraminidase inhibitor (oseltamivir) the previous day. Colonoscopic examination revealed an area of hemorrhage and erosion in the left transverse colon. After halting oseltamivir treatment these symptoms disappeared and her colonoscopic findings improved. A drug-induced lymphocyte stimulation test was positive for oseltamivir. This case is the first reported case of acute hemorrhagic colitis induced by oseltamivir. 相似文献
58.
Satoshi Tobe Kazunori Yoshida Masahiro Yamaguchi Haruko Nishimura Masahito Kawata 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2006,54(7):308-310
Papillary fibroelastoma (PFE) is a rare and benign cardiac tumor typically found on the valvular endocardium. In most cases,
PFE is identified incidentally on echocardiography or during cardiac surgery. The patient was a 73-year-old man who had been
treated for hepatocellular carcinoma for 5 years. On echocardiography, a 2.5-cm diameter mass was detected in the pulmonary
trunk just above the pulmonary valve. Through a transpulmonary arterial approach with cardiopulmonary bypass, the mass identified
on the commissure of the right and posterior pulmonary cusp was surgically excised together with the attached endocardium.
Despite the benign histology of PFE, lethal embolic events such as stroke, myocardial infarction, and pulmonary embolism are
reported in some cases. To prevent such complications, tumor identification and surgical excision are essential. 相似文献
59.
Yasuhiro Kinoshita M.D. Ph.D. Isao Sato M.E. Teruhiko Marushima B.E. Taichi Nishimura B.E. 《The International journal of angiology》1994,3(1):36-40
In order to find the three-dimensional distribution of ventricular depolarization potentials in left anterior hemiblock (LAHB) diagnosed by the conventional scalar ECG, 7 subjects with LAHB aged 9 to 62 years old who were otherwise healthy were studied by computer graphic electrocardiography (CGECG).Two modes of the initial ventricular depolarization (IVD) were noted. (1) The IVD appeared irregularly and separately on the mid- to lower central region of the anterior body surface. (2) The IVD appeared in a form rather like a parallelogram on the central region of the anterior body surface. Both (1) and (2) potentials propagated toward the left middle, lower, and lateral regions of the anterior body surface as normally observed; however, they were far lower in voltage than those observed in intact subjects.From the results, it has been concluded that LAHB may be, not a block, but rather a defective ventricular septal conduction.Presented at the 34th Annual Congress, International College of Angiology, Budapest, Hungary, July 1992. 相似文献
60.
A Tsujimura K Nishimura K Matsumiya T Oka M Takaha R Arima A Kurata 《Hinyokika kiyo. Acta urologica Japonica》1992,38(9):1037-1040
A case of retroperitoneal venous aneurysm is reported. A 73-year-old woman was referred to us with the chief complaint of left abdominal mass. A giant abdominal mass was palpable and diagnostic imaging examination including ultrasound tomography, excretory pyelography, computed tomography, magnetic resonance imaging and angiography revealed a giant cystic mass encircled by calcification in the left retroperitoneal space. Operation for this cystic mass was performed under the preoperative diagnosis of a giant left renal cyst. During operation the mass was located between the left kidney and the left adrenal gland. Because it was difficult to separate the mass from the left kidney the mass was removed with the left kidney. The extirpated tumor measured 15.5 x 15.0 x 9.5 cm and contained old blood clots and red-yellow colored fluid. A histological examination revealed that the tumor wall was composed of smooth muscle and elastic fibers. Therefore, pathological diagnosis was retroperitoneal venous aneurysm. Retroperitoneal venous aneurysm is very rare. To our knowledge, this is the 8th case of retroperitoneal venous aneurysm reported in Japan. 相似文献