全文获取类型
收费全文 | 2527篇 |
免费 | 114篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 86篇 |
妇产科学 | 25篇 |
基础医学 | 200篇 |
口腔科学 | 72篇 |
临床医学 | 128篇 |
内科学 | 666篇 |
皮肤病学 | 67篇 |
神经病学 | 187篇 |
特种医学 | 210篇 |
外科学 | 438篇 |
综合类 | 13篇 |
预防医学 | 78篇 |
眼科学 | 22篇 |
药学 | 138篇 |
中国医学 | 5篇 |
肿瘤学 | 301篇 |
出版年
2023年 | 7篇 |
2022年 | 19篇 |
2021年 | 41篇 |
2020年 | 22篇 |
2019年 | 39篇 |
2018年 | 53篇 |
2017年 | 39篇 |
2016年 | 41篇 |
2015年 | 49篇 |
2014年 | 75篇 |
2013年 | 72篇 |
2012年 | 148篇 |
2011年 | 163篇 |
2010年 | 77篇 |
2009年 | 81篇 |
2008年 | 162篇 |
2007年 | 160篇 |
2006年 | 164篇 |
2005年 | 165篇 |
2004年 | 155篇 |
2003年 | 140篇 |
2002年 | 146篇 |
2001年 | 82篇 |
2000年 | 58篇 |
1999年 | 64篇 |
1998年 | 33篇 |
1997年 | 31篇 |
1996年 | 20篇 |
1995年 | 24篇 |
1994年 | 15篇 |
1993年 | 8篇 |
1992年 | 37篇 |
1991年 | 24篇 |
1990年 | 24篇 |
1989年 | 21篇 |
1988年 | 16篇 |
1987年 | 24篇 |
1986年 | 20篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 5篇 |
排序方式: 共有2653条查询结果,搜索用时 500 毫秒
21.
Naoki Horikawa Tomoyuki Suzuki Takaoki Uchiumi Tetsuji Minamimura Kazuhiro Tsukada Noriaki Takeguchi Hideki Sakai 《The Journal of physiology》2005,562(3):885-897
Increased release of thromboxane A2 (TXA2 ) has been shown to be involved in inflammatory bowel diseases. In the present study, we have investigated the effect of a stable TXA2 analogue (STA2 ) on the electrical parameters in isolated human colonic mucosa. In the human mucosa set between Ussing chambers, STA2 stimulated Cl− secretion in a concentration-dependent manner with an EC50 of 0.06 μ m . The STA2 -induced Cl− secretion was significantly inhibited by ONO-3708 (10 μ m ), a specific TXA2 receptor antagonist. The effect of STA2 (0.3 μ m ) was independent of the colonic segment from which the tissue was obtained, from caecum to rectum. Chromanol 293B, an inhibitor of the cAMP-dependent KvLQT1 channel, attenuated the STA2 -induced Cl− secretion in the human colonic mucosa (IC50 value 1.18 μ m ). We found that KvLQT1 mRNA and protein were expressed in all the tested segments of the human colon. The STA2 -induced Cl− secretion was significantly inhibited by 8-bromo-2'-monobutyryladenosine-3',5'-cyclic monophosphorothioate (50 μ m ), a membrane-permeant cAMP antagonist. STA2 (0.3 μ m ) significantly increased the intracellular cAMP levels and the short-circuit current via TXA2 receptor in a human colonic cell line. These results suggest that the TXA2 -induced Cl− secretion in the colon is mediated via the cAMP pathway in addition to the Ca2+ –calmodulin pathway which was previously reported. 相似文献
22.
Kitada S Maekura R Toyoshima N Naka T Fujiwara N Kobayashi M Yano I Ito M Kobayashi K 《Clinical and diagnostic laboratory immunology》2005,12(1):44-51
We report the development of a serodiagnostic method for Mycobacterium avium complex (MAC) disease with an enzyme immunoassay (EIA) with the MAC-specific glycopeptidolipid (GPL) core as the antigen. In this study, we confirmed by EIA that the GPL core antibody was in the sera of immunocompetent patients with MAC disease. The EIA for quantifying the GPL core antibody was evaluated as a clinical tool for serodiagnosis of pulmonary MAC disease. A significant increase in GPL core antibodies (immunoglobulins G, A, and M) was detected in sera of patients with MAC pulmonary diseases when they were compared to patients who were colonized with MAC, patients with Mycobacterium kansasii disease or tuberculosis, and healthy subjects. The sensitivities and specificities of the GPL core-based EIA for diagnosis of MAC pulmonary disease were 72.6% and 92.2%, respectively, for IgG, 92.5% and 95.1%, respectively, for IgA, and 78.3% and 91.0%, respectively, for IgM. The best sensitivity and specificity were obtained by measuring immunoglobulin A antibodies against GPL core antigen. The level of GPL core antibodies reflected disease activity, since it decreased in cured MAC patients who had responded to chemotherapy. Measurement of serum antibodies against GPL core is useful for both diagnosis and assessment of disease activity in MAC disease of the lung. 相似文献
23.
Sengoku K Takuma N Miyamoto T Horikawa M Ishikawa M 《Human reproduction (Oxford, England)》2004,19(3):639-644
BACKGROUND: We investigated whether integrins are required forthe human spermoocyte binding and fusion processes. METHODS:The expression of several integrin subunits at the human oocyteplasma membrane was investigated using immunofluorescence microscopy,and the functional role of integrins expressed at the humanoocyte surface in spermoocyte interaction was studiedusing a zona-free human oocyte binding and fusion assay. A totalof 144 unfertilized oocytes were stained with anti-integrinantibodies and 147 zona-free unfertilized oocytes were inseminatedin the presence of various anti-integrin antibodies that wereexpressed in oocyte plasma membrane. RESULTS: The antibodiesof six integrin subunits (2, 3, 5, 6, V, M) and six integrinsubunits (1, 2, 3, 4, 5, 6) were bound to the surface of fixedunfertilized oocytes. In contrast, the presence of 1 and 4 subunitscould not be verified. The human spermoocyte bindingwas only partially inhibited by blocking antibodies of 2, 3,5, 6, V, M, 1, 2 and 3 with a maximum of 55% inhibition, butantibodies of 4, 5 and 6 showed no effect on spermoolemmalbinding. A similar reduction of the number of fused sperm wasobserved. However, the ratio of fused sperm to total sperm (boundand fused) was not impaired by all integrin antibodies, suggestingthat integrins had no role in the spermoolemmal fusionprocess. CONCLUSIONS: These results suggest that one of thebinding mechanisms can be inhibited by integrin antibodies butthat this mechanism does not play an essential role in the humanspermoolemmal binding and fusion processes. The othermechanisms, insensitive to integrins, may involve both bindingand fusion processes in human oocytes. 相似文献
24.
Activities of single cochlear nerve fibers of Wistar rats were recorded extracellularly. Best frequencies (BF) distributed from 0.50 to 62.6 kHz. The audiogram was made as the minimum boundary of the BF threshold distribution. The range of audible frequency was 0.54-63 kHz at 60 dB SPL and 0.15-67 kHz at 100 dB SPL. The lowest trough of the audiogram was 5 dB SPL at 41.2 kHz. There was the second trough of 10 dB SPL at 7.01 kHz leaving a notch between the two troughs. The shapes of the frequency-threshold curves (FTCs) of fibers were evaluated quantitatively and typical FTCs were shown as a function of BF. 相似文献
25.
Seigo Maeo Yoichi Ajioka Hidenobu Watanabe Masaaki Kobayashi Michio Kobayashi 《Pathology international》1995,45(5):359-365
Well-differentiated colorectal adenocarcinomas are subclassified into carcinoma with high-grade atypia (CAH) and carcinoma with low-grade atypia (CAL) based on their cellular atypia. It is proposed that CAH and CAL are different in histologic prognostic factors and that the former should be regarded as carcinoma with high-grade malignancy and the latter as low-grade malignancy. In this study, the differences in cell-proliferative activity between CAH and CAL were examined using a monoclonal antibody to the proliferating cell nuclear antigen (PCNA). The PCNA index and mitotic index of 27 early colorectal carcinomas (9 CAL, 5 CAH, and 13 carcinomas with mixed low- and highgrade atypia) was evaluated in relation to their depth of invasion. In intra-mucosal lesions, both indices were higher in CAH (78%, 0.89%) than in CAL (68%, 0.47%; P <0.01). In lesions invading into the submucosa, the PCNA and mitotic indices were also higher in CAH (7596, 0.65%) than in CAL (35%, 0.19%; P <0.01). A significant correlation was observed between the PCNA index and the mitotic index in the mucosal lesions (P<0.05). These results indicate that CAH has a higher proliferative activity than CAL, and support the current authors' proposal that CAH is a high-grade malignancy and CAL a low-grade malignancy. 相似文献
26.
Multiple time axes for representation of echo delays in the auditory cortex of the mustached bat 总被引:1,自引:0,他引:1
The properties of the orientation sound (pulse) of the Jamaican mustached bat, Pteronotus parnellii parnellii is the same as the Panamanian mustached bat, P.p. rubiginosus. It consists of four harmonics, each containing a long constant-frequency (CF) component followed by a short frequency-modulated (FM) component. Thus, there are eight components in total: CF1-4 and FM1-4. The combination-sensitive area of the auditory cortex in P.p. parnellii consists of two major divisions (FM-FM and CF/CF areas) as in P.p. rubiginosus. The FM-FM area projects to the dorsal fringe (DF) and other areas. Response latencies of neurons in the DF area are longer than those in the FM-FM area. The distribution of latencies is unimodal for the FM-FM area, but bimodal for the DF area. In this electrophysiological study of the response properties of neurons in the DF and FM-FM areas, our aim was to find out how signal processing might be different between the two areas. Both the FM-FM and DF areas consist of three types of FM-FM combination-sensitive neurons: FM1-FM2, FM1-FM3, and FM1-FM4. They do not respond or respond poorly to pulse alone, echo alone, single CF tones or single FM sounds. But they show strong facilitation of response to the echo when it is delivered with particular delays from the pulse. The essential elements in the pulse-echo pair for facilitation are the FM1 of the pulse and FM2 or FM3 or FM4 of the echo. In both the FM-FM and DF areas, the great majority of neurons show short-lasting facilitation, and other neurons show long-lasting facilitation. FM-FM neurons are tuned to particular echo delays, i.e., target ranges. In both the FM-FM and DF areas, the width of a delay-tuning curve is linearly related to the value of a best delay. There is no sign that processing of range information is more specialized in the DF area than the FM-FM area. In both the FM-FM and DF areas, three types of FM-FM neurons form independent clusters. Along the major axis of each cluster, best delays for facilitative responses of neurons systematically change according to the loci of the neurons. The more posterior the location, the longer the best delay is. Therefore, there are six time (i.e., range) axes in total. The time axis in the DF area is shorter than that in the FM-FM area.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
27.
Luigi Camera Seigo Kinuya Kayhan Garmestani Martin W. Brechbiel Chuanchu Wu Lee H. Pai Thomas J. McMurry Otto A. Gansow Ira Pastan Chang H. Paik Jorge A. Carrasquillo 《European journal of nuclear medicine and molecular imaging》1994,21(7):640-646
The biodistribution of indium-111/yttrium-88-labeled B3 monoclonal antibody, a murine IgG1k, was evaluated in non-tumor-bearing mice. B3 was conjugated to either 2-(p-SCN-Bz)-6-methyl-DTPA (1B4M) or 2-(p-SCN-Bz)-1,4,7,10 tetraazacyclododecane tetra-acetic acid (2B-DOTA) and labeled with 111In at 1.4–2.4 mCi/mg and 88Y at 0.1–0.3 mCi/mg. Non-tumor-bearing nude mice were co-injected i.v. with 5–10 Ci/4–10 g of 111In/88Y-labeled B3 conjugates and sacrificed at 6 h and daily up to 168 h post-injection. Mice injected with 111In/88Y (IB4M)-B3 showed a similar biodistribution of the two radiolabels in all tissues except the bones, where significantly higher accretion of 88Y than 111In was observed, with 2.8% ± 0.2% vs 1.3% ± 0.16% ID/g in the femur at 168 h, respectively (P<0.0001). In contrast, mice receiving the 111In/88Y-(DOTA)-B3 conjugate showed significantly higher accumulation of 111In than 88Y in most tissues, including the bones, with 2.0% ± 0.1% vs 1.2% ± 0.09% ID/g in the femur at 168 h, respectively (P<0.0001). Whereas the ratios of the areas underneath the curve (%ID × h/g) in the blood, liver, kidney and bone were 0.96, 1.12, 1.13, and 0.74 for 111In/88Y-(IB4M)-B3 and 0.84, 1.23, 1.56, and 1.31 for 111In/88Y (DOTA)-B3, respectively, ratios 1 were observed between 111In-(IB4M)-B3 and 88Y-(DOTA)-B3. In summary, while neither IB4M nor DOTA was equally stable for 111In and 88Y, the fate of 88Y- (DOTA)-B3 could be closely traced by that of 111 In-(IB4M)-B3. 相似文献
28.
Distinctions between microglial cells and peripheral macrophages with regard to adhesive activities and morphology. 总被引:1,自引:0,他引:1
K Toku J Tanaka S Fujikata Y Hamamoto Y Horikawa K Miyoshi N Tateishi Y Suzuki N Maeda 《Journal of neuroscience research》1999,57(6):855-865
Activated microglial cells and peripheral macrophages are hardly distinguishable from the viewpoints of morphology and function. There are various immunological markers common to both microglial cells and peripheral macrophages. In the present study, however, we found that microglial cells have distinct characters in terms of adhesion and morphology. By using a "rheoscope," that is an apparatus to rheologically measure the strength of cell adhesion to substrates, rat microglial cells were found to attach to polystyrene dishes much more weakly than alveolar and peritoneal macrophages. Interferon-gamma (IFNgamma) strengthened the adhesion of alveolar and peritoneal macrophages, whereas it weakened that of microglial cells. Morphological changes of microglial cells induced by IFNgamma were also different from those of peripheral macrophages. Furthermore, alveolar and peritoneal macrophages produced NO in response to IFNgamma, while microglial cells did not. When cultured on astrocyte-derived extracellular matrix (AsECM) in serum-free medium, only microglial cells extended multiple ramified processes. Conversely, alveolar and peritoneal macrophages on AsECM shrunk their ruffling membrane and rounded up. These distinctions between microglial cells and macrophages may reflect differences in cell lineages as well as environments in which individual cells reside. 相似文献
29.
30.
Naofumi Ohsawa Shinya Uchino Takao Saito Masaki Miyahara Tokuji Inoue Seigo Kitano 《International journal of clinical oncology / Japan Society of Clinical Oncology》1997,2(4):230-234
Background Deletions involving chromosome 9p21, on which the tumor suppressor genep16/MTS1 is located, have been noted in esophageal cancer. We investigated the relationship between the deletion of chromosome 9p21–22
and the clinical features of esophageal cancer.
Methods We examined the loss of heterozygosity (LOH) on chromosome 9p21–22 in 56 esophageal cancers using polymerase chain reaction
(PCR) analysis and 2 microsatellite markers (RPS6 and IFNA).
Results In 18 out of 50 informative cases (36%), LOH had occurred at 1 or 2 loci on chromosome 9p21–22. We found no relationship between
LOH on chromosome 9p21–22 and patient sex, age tumor length, location, histologic differentiation, depth of tumor invasion,
the extent of lymph node metastasis, histologic stage, or curability. Among 35 patients without an absolute noncurative resection,
the mean survival of 11 patients with LOH on chromosome 9p21–22 was 19.3 months, compared with 42.3 months for 24 patients
with a normal allele; thus, the survival rate of those with LOH was significantly lower than that of patients without LOH
on chromosome 9p21–22 (log-rank test;P=0.03).
Conclusion These data suggest that LOH on chromosome 9p21–22, on which the cell-cycle regulatorp16/MTS1 gene is located, may be related to cancer development, and probably can serve as a clinical marker for evaluating a patient's
prognosis. 相似文献