全文获取类型
收费全文 | 6269篇 |
免费 | 288篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 132篇 |
妇产科学 | 82篇 |
基础医学 | 856篇 |
口腔科学 | 163篇 |
临床医学 | 389篇 |
内科学 | 1454篇 |
皮肤病学 | 67篇 |
神经病学 | 534篇 |
特种医学 | 236篇 |
外国民族医学 | 1篇 |
外科学 | 1299篇 |
综合类 | 42篇 |
预防医学 | 120篇 |
眼科学 | 118篇 |
药学 | 488篇 |
中国医学 | 10篇 |
肿瘤学 | 577篇 |
出版年
2023年 | 30篇 |
2022年 | 61篇 |
2021年 | 106篇 |
2020年 | 66篇 |
2019年 | 81篇 |
2018年 | 111篇 |
2017年 | 107篇 |
2016年 | 102篇 |
2015年 | 104篇 |
2014年 | 132篇 |
2013年 | 198篇 |
2012年 | 327篇 |
2011年 | 352篇 |
2010年 | 216篇 |
2009年 | 208篇 |
2008年 | 322篇 |
2007年 | 313篇 |
2006年 | 326篇 |
2005年 | 331篇 |
2004年 | 311篇 |
2003年 | 289篇 |
2002年 | 311篇 |
2001年 | 163篇 |
2000年 | 194篇 |
1999年 | 182篇 |
1998年 | 105篇 |
1997年 | 65篇 |
1996年 | 76篇 |
1995年 | 63篇 |
1994年 | 53篇 |
1993年 | 57篇 |
1992年 | 132篇 |
1991年 | 108篇 |
1990年 | 122篇 |
1989年 | 124篇 |
1988年 | 97篇 |
1987年 | 91篇 |
1986年 | 67篇 |
1985年 | 73篇 |
1984年 | 57篇 |
1983年 | 42篇 |
1982年 | 24篇 |
1981年 | 19篇 |
1980年 | 28篇 |
1979年 | 29篇 |
1977年 | 21篇 |
1973年 | 23篇 |
1972年 | 19篇 |
1970年 | 20篇 |
1968年 | 19篇 |
排序方式: 共有6595条查询结果,搜索用时 15 毫秒
1.
Two-color flow cytometry was carried out to determine the correlation between cell-mediated immunity and the levels of proteinuria in 30 patients with membranous nephropathy. Lymphocyte subpopulations were measured by two-color flow cytometry using various monoclonal antibodies of the Leu series. Clinically, the patients were divided into four stages as follows: 1. untreated nephrotic stage, 2. prednisolone (PSL) treated nephrotic stage, 3. persistent proteinuric stage (incomplete remission, ICR) and 4. complete remission (CR). Two-color flow cytometry showed a significant decrease in Leu 2a+15+ (suppressor T) cells and relative increase in Leu 3a+8+ (suppressor inducer T) cells in the untreated nephrotic stage. The mean Leu 3a+8-/Leu 2a+15+ (helper/suppressor) cell ratio was normalized in the persistent proteinuric stage or complete remission after treatment with PSL. Patients with membranous nephropathy showed a significant elevation of Leu 2a+DR+ cells after treatment with PSL. The abnormalities of suppressor T cells and suppressor inducer T cells in the peripheral blood appear to reflect the levels of proteinuria in patients with membranous nephropathy. It was concluded that PSL might stimulate Leu 2a positive cells and then increase the number of Leu 2a+15+ cells in the peripheral blood of patients with membranous nephropathy. 相似文献
2.
Shoichi Sasaki 《Neuropathology》1993,13(3):185-192
I briefly review spheroids observed in the anterior horns of the spinal cord in amyotrophic lateral sclerosis (ALS). Spheroids are argentophilic bodies more than 20 μm in diameter. Recently, some connections between the proximal axonal swellings including spheroids and the perikarya have been reported in some ALS patients with a short clinical course or mild depletion of anterior horn neurons. Most of the cell bodies directly connected with the axonal swellings appear normal, and spheroids are considered to be one of the hallmarks of the early histological changes in this disorder. Spheroids are strongly positive with anti-phosphorylated neurofilament antibody, and are also positive with calcitonin gene-related peptide and anti-peripherin antibody. Some spheroids are immunostained with anti-synaptophysin antibody and anti-ubiquitin antibody. Spheroids are not immunostained with anti-phosphorylated tau antibody, or high molecular weight microtubule associated proteins. Electron microscopically, spheroids are usually composed of densely packed accumulation of 10 nm neurofilaments with a variety of orientations, plus vesicles, dense bodies and mitochondria. When the swellings of the initial segment is relatively pronounced, the undercoating is obscured and the neurofilaments become interwoven in some parts. In the first internode of the myelinated axons, as the swellings become larger, the neurofilaments lose their parallel orientation and become intermingled. Large accumulation of neurofilaments resembling spheroids in the perikarya of large anterior horn cells suggests that spheroids could be derived not only from the axon including the proximal portion, but also from the perikarya. Structures apparently identical to axonal spheroids are observed at the light and electron microscopic levels in the proximal portion of axons of anterior horn cells in animal models intoxicated with β, β'-iminodipropionitrile (IDPN), or with aluminum, in hereditary canine spinal muscular atrophy (HCSMA). The pathogenetic mechanism is probably associated with an impairment in slow axonal transport which particularly affects the neurofilaments in IDPN and aluminum intoxication. Impairment of slow axonal transport of neurofilaments also plays an important role in the pathogenesis of ALS. The average diameter of even normalappearing initial segment is larger in ALS than in the controls. The perikarya connected with the swollen proximal axons and their dendrites almost always appear normal. These findings suggest that the slow axonal transport of neurofilaments is probably impaired in this portion of the axon at an early stage in ALS as well as animal models for human ALS. However, techniques to analyze slow axonal transport in humans still remain tobe developed. Recently, overexpression of neurofilament subunits in transgenic mice produces a condition resembling ALS. The transgenic model may offer an interesting perspective not only for testing therapeutic strategies but also for investigating in a systematic way the various genetic and environment factors controlling the onset and progression of the disease and might yield new insights on the etiology of ALS. 相似文献
3.
H S Ozaki K Iwahashi M Tsubaki Y Fukui Y Ichikawa Y Takeuchi 《Journal of neuroscience research》1991,28(4):518-524
The presence of cytochrome P-45011 beta in rat brain was studied by immunohistochemistry using polyclonal rabbit antibodies raised against purified bovine adrenocortical P-45011 beta, which is involved in the steroid 11 beta-hydroxylation and glucocorticoid formation. The results showed that cytochrome P-45011 beta immunoreactivity is selectively localized to the tracts of myelinated fibers throughout the brain. The specificity of immunohistochemical stainings with P-45011 beta antibodies was established by control tests including nonimmune rabbit immunoglobulin Gs and P-45011 beta antibodies absorbed with purified antigen. Western immunoblots of homogenates from different brain areas with P-45011 beta antibodies, together with biochemical enzymatic assays for cytochrome P-45011 beta monooxygenase activity in these homogenates, confirmed the selective localization of this enzyme observed with immunohistochemistry. Cytochrome P-45011 beta and 11 beta-hydroxylase activity were detected in a homogenate from the cortical white matter (brain area rich in myelinated fibers) as in that from the rat adrenal, but were not detectable in a homogenate from the cerebral cortex (brain area poor in myelinated fibers). Furthermore, quantitation of the P-45011 beta bands on the immunoblots by the areal density revealed that the cortical white matter contains approximately 1.4 pmol of cytochrome P-45011 beta/mg of tissue protein, the value of which was about one sixth of the corresponding value estimated in the rat adrenal. This relatively high content of cytochrome P-45011 beta was also reflected in a relatively high level of 11 beta-hydroxylase activity measured in a homogenate of this brain area by biochemical enzymatic assays using [4-14C]-11-deoxycorticosterone.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
For monitoring the changes in intracellular free Ca2+ concentration ([Ca2+]i), we developed a simple system combining a fluorescence microscope, an image intensifier, a video-camera, a cathode ray tube display and a photodiode, employing quin2 as a Ca2+ indicator. We recorded increases of the fluorescence intensity due to [Ca2+]i rises, when high K+ medium, neurotransmitter and Ca2+ ionophore were applied to the single cells of nervous system origin in culture. The present system is capable of simultaneous detection of the [Ca2+]i changes from multiple separate cells. 相似文献
5.
6.
Tsutomu Yasutake Daisuke Nagatomo Toshihiko Mizuta Yuichiro Eguchi Takanori Kumagai Keisuke Ario Iwata Ozaki Tateo Kuno Kazuma Fujimoto 《Nihon Shokakibyo Gakkai zasshi》2007,104(12):1752-1757
A 16-year-old man was admitted to our hospital with nausea, general fatigue, and consciousness disturbance along with extreme hyperammoniemia eight days after the onset of symptoms. Familial history and the high concentration of orotic acid in urine lead us to a diagnosis of OTCD. We immediately initiated intensive treatment such as continuous hemodiafiltration and sodium benzoate administration; however, the patient died twelve days after admission. Since OTCD is not so rare and can be found in all ages, it should be considered fundamental for evaluation of hyperammoniemia. This case suggested that for a better prognosis of OTCD patients it is very important to prevent such an onset, and to make an as early as possible diagnosis and start to treatment. 相似文献
7.
8.
9.
Akitomo Shimoji M.D. Shoichi Katsuragi M.D. Taihei Miyakawa M.D. Ryoichi Hira M.D. Kenjiro Watanabe M.D. Kohei Miyakawa M.D. Takateru Ishitsu M.D. Teruhisa Miike M.D. 《Psychiatry and clinical neurosciences》1987,41(1):47-55
Abstract: We report here two cases in a family with pleomorphic clinical features which include mitochondrial myopathy, encephalopathy, stroke-like episodes, episodic disturbances of consciousness and other multisystemic abnormalities. The other signs observed in multisystemic abnormalities were ophthalmoplegia, short stature, diabetes mellitus, diabetes insipidus, renal dysfunction, optic atrophy, retinal degeneration, impairment of hearing and mental retardation or deterioration. A symptomatological variation was observed in cases in the same family. It is suggested that these widely varying symptoms may be expressions caused by a common biochemical defect which involves different tissuesin different individuals in the family. The syndromes observed in the present cases were compared with other possibly-related mitochondrial encephalomyopathies. 相似文献
10.
Matsukawa T.; Hanagata K.; Ozaki M.; Iwashita H.; Koshimizu M.; Kumazawa T. 《British journal of anaesthesia》1997,78(4):396-399
We tested the hypothesis that premedication with i.m. midazolam decreases
core temperature dose-dependently. We studied six male volunteers, in
random order, on 3 days: (1) no midazolam administration (control day), (2)
midazolam 0.025 mg kg-1 i.m., (3) midazolam 0.075 mg kg-1 i.m. On the first
day, subjects were maintained alert during a 30- min control period. On the
second and third days, midazolam 0.025 or 0.075 mg kg-1 was administered
i.m. Core temperatures were measured at the right tympanic membrane. Four
adhesive skin surface probes were fixed on the chest, upper right arm,
lateral calf and thigh. Finger tip perfusion was evaluated using forearm
minus fingertip and calf minus toe, skin surface temperature gradients.
Thirty minutes after midazolam i.m., the level of sedation in the
volunteers was assessed. Peripheral venous blood was obtained immediately
after the assessment of the level of sedation. Tympanic membrane
temperatures after administration of midazolam 0.075 mg kg-1 i.m. were
significantly lower than those on the control and midazolam 0.025 mg kg-1
i.m. days at 20 and 30 min. The decreases in tympanic membrane temperatures
at 30 min after midazolam i.m. became larger as the volunteers were more
deeply sedated. i.m. midazolam produced a concentration-dependent decrease
in tympanic membrane temperature at 30 min after midazolam 0.025 and 0.075
mg kg-1 i.m. We conclude that midazolam impaired tonic thermoregulatory
vasoconstriction, allowing core-to-peripheral heat redistribution in a
dose-dependent manner after i.m. administration.
相似文献