全文获取类型
收费全文 | 2466篇 |
免费 | 163篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 50篇 |
妇产科学 | 16篇 |
基础医学 | 439篇 |
口腔科学 | 38篇 |
临床医学 | 293篇 |
内科学 | 367篇 |
皮肤病学 | 61篇 |
神经病学 | 248篇 |
特种医学 | 185篇 |
外科学 | 301篇 |
综合类 | 27篇 |
一般理论 | 1篇 |
预防医学 | 168篇 |
眼科学 | 66篇 |
药学 | 184篇 |
中国医学 | 2篇 |
肿瘤学 | 173篇 |
出版年
2022年 | 24篇 |
2021年 | 44篇 |
2020年 | 18篇 |
2019年 | 23篇 |
2018年 | 51篇 |
2017年 | 24篇 |
2016年 | 49篇 |
2015年 | 48篇 |
2014年 | 51篇 |
2013年 | 69篇 |
2012年 | 121篇 |
2011年 | 123篇 |
2010年 | 65篇 |
2009年 | 72篇 |
2008年 | 113篇 |
2007年 | 128篇 |
2006年 | 104篇 |
2005年 | 96篇 |
2004年 | 71篇 |
2003年 | 82篇 |
2002年 | 81篇 |
2001年 | 98篇 |
2000年 | 82篇 |
1999年 | 76篇 |
1998年 | 59篇 |
1997年 | 33篇 |
1996年 | 42篇 |
1995年 | 25篇 |
1994年 | 31篇 |
1993年 | 23篇 |
1992年 | 52篇 |
1991年 | 50篇 |
1990年 | 41篇 |
1989年 | 38篇 |
1988年 | 31篇 |
1987年 | 34篇 |
1986年 | 37篇 |
1985年 | 30篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1981年 | 20篇 |
1979年 | 30篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1976年 | 23篇 |
1975年 | 28篇 |
1974年 | 24篇 |
1973年 | 20篇 |
1972年 | 39篇 |
1971年 | 23篇 |
排序方式: 共有2684条查询结果,搜索用时 15 毫秒
11.
Rat mesangial cells were shown to be sensitive to recombinant interferon-gamma (IFN-gamma). IFN-gamma reduced thymidine uptake by these cells and inhibited cell proliferation. Incubation of the cells with 1000 U/ml IFN-gamma decreased thymidine uptake by up to 64% and cell numbers were decreased by 17%. The effects of IFN-gamma were dose and time dependent and were partially reversible by the anti-IFN-gamma monoclonal antibody DB-1. This lymphokine did not reduce incorporation of RNA and protein precursors however. Measurements of 3H-uridine and 3H-leucine incorporation indicated significant increases in RNA and protein synthesis (37% and 45%, respectively) on a per cell basis. The mitogenic effects of IL-1 and platelet-derived growth factor (PDGF) were also susceptible to IFN-gamma-mediated inhibition but the mitogenic response to epidermal growth factor (EGF) was much less sensitive. We conclude that while IFN-gamma may act to modulate the mitogenic signals provided by some factors such as IL-1 and PDGF, the response to EGF appears to be unaffected. 相似文献
12.
Uroscopy in the 21st century: high-field NMR spectroscopy 总被引:1,自引:1,他引:0
Neild GH; Foxall PJ; Lindon JC; Holmes EC; Nicholson JK 《Nephrology, dialysis, transplantation》1997,12(3):404-417
From the experiments described, it can be seen that there are different
research approaches that can be taken and these are summarized in Table 1.
Whereas much scientific research is principally hypothesis led, there
remains, nevertheless, an important place for exploratory research. High
resolution NMR can measure, directly and simultaneously, a wide range of
endogenous metabolites in biological fluids and has the unique capability
of providing structural information on the metabolites detected. It has
proved to be a powerful research tool with which to study inherited
metabolic diseases, renal disease, drug metabolism, and toxicity, and can
be used to monitor the effects of drug therapy. For instance, by using a
library of experimental toxins one can map the metabolic profile of
site-specific nephron injury. With this approach in man one could
eventually take an unknown disease such as Balkan nephropathy and predict
the initial site of tubular injury, the mode of injury and therefore the
kind of toxin capable of producing that injury. NMR spectroscopic
techniques are still advancing rapidly, with ever increasing sensitivity
and sophistication of NMR pulse sequences to enhance structural elucidation
in complex mixtures. Given the advances in directly coupled HPLC-NMR and
even HPLC-NMR-mass spectroscopy it is likely that these technologies in
conjunction with pattern recognition will make major contribution to our
understanding of renal processes and provide new diagnostic insights in the
21st century.
相似文献
13.
Benign coital headache 总被引:1,自引:0,他引:1
John R Østergaard Morten Kraft 《Cephalalgia : an international journal of headache》1992,12(6):353-355
We studied the natural history of patients with a diagnosis of benign coital headache who presented to a private neurological clinic between the years 1978 and 1991. Thirty-two patients (24M, 8F) were invited to participate and 26 patients (83%) responded. The period of follow-up ranged from six months to 14 years (median 6 years). Thirteen patients (50%) had recurrent attacks of coital headache epochs separated by intervals of up to 10 years. Eleven of these patients suffered a concomitant primary headache whereas this was present in only one of those patients without recurrent attacks of coital headache (p < 0.001). In all but one patient, who had a transient blurred vision, the headache was not accompanied by nausea, vomiting, visual disturbances, sensory/motor disturbances, or unconsciousness. We concluded that benign coital headache can be clearly distinguished from headaches due to cerebral aneurysm or arteriovenous malformation rupture. The presence of a concomitant primary headache syndrome is a risk-factor for recurrence of coital headache. 相似文献
14.
D. Nadal R. Caduff R. Kraft M. Salfinger T. Bodmer P. Kirschner E. C. Böttger U. B. Schaad 《European journal of clinical microbiology & infectious diseases》1993,12(1):37-43
Three children with human immunodeficiency virus infection and invasive infection withMycobacterium genavense are reported. Fever spikes, abdominal cramps and distension, diarrhea or ileus, and anemia were the predominant symptoms in the severely immunodeficient patients (CD4 lymphocytes<0.04 × 109/l). Numerous acid-fast bacilli were readily detectable by microscopy in stool samples and in lymph node biopsies, but cultures for mycobacteria remained negative.Mycobacterium genavense should be sought when invasive non-tuberculous mycobacteriosis is suspected and mycobacterial cultures from blood or other sites show limited growth. Multiple-drug regimens including amikacin, ethambutol, rifampin, and clarithromycin may be of benefit in controlling the infection, as observed in two patients. 相似文献
15.
16.
RHD maternal-fetal genotype incompatibility and schizophrenia: extending the MFG test to include multiple siblings and birth order 总被引:3,自引:0,他引:3
Kraft P Palmer CG Woodward AJ Turunen JA Minassian S Paunio T Lönnqvist J Peltonen L Sinsheimer JS 《European journal of human genetics : EJHG》2004,12(3):192-198
Rh incompatibility disease (ie Rh hemolytic disease of the fetus and newborn) has been implicated as a risk factor for schizophrenia. Here, we extend the maternal-fetal genotype incompatibility (MFG) test used in an earlier case-parent trio study that found significant evidence for an increased risk of schizophrenia in RHD MFG-incompatible children. We modify the MFG test for case-parent trios to include any number of siblings. This modified test enables us to use more of the available data from the earlier study. The increased sample size not only gives us greater power to test for MFG incompatibility but it also enables us to model the impact of previous RHD MFG-incompatible pregnancies on the relative risk of RHD MFG incompatibility in later-born siblings. This modeling is important, because RHD MFG incompatibility is a proxy for Rh incompatibility disease, and the risk of Rh incompatibility disease increases with the number of previous RHD MFG-incompatible pregnancies. The best-fitting models are consistent with the hypothesized effect that previous incompatible pregnancies increase the risk of schizophrenia due to RHD MFG incompatibility. There was significant evidence that the relative risk of schizophrenia in the second- and later-born RHD MFG-incompatible children is 1.7, consistent with earlier estimates. Our extension of the MFG test has general application to family-based studies of maternal-genotype and MFG interaction effects. 相似文献
17.
Schwerer MJ Hemmer J Kraft K Maier H Möller P Barth TF 《Virchows Archiv : an international journal of pathology》2003,443(1):98-103
We report the case of a 58-year-old man who presented with a squamous cell carcinoma pT1a G2 of the left vocal cord. Six months after histologically verified complete resection, the patient experienced an endolaryngeal and extralaryngeal local recurrence pT4 pN2b G2. We applied DNA flow cytometry (FCM) and comparative genomic hybridization (CGH) on both primary and recurrent tumor. The primary tumor and the endolaryngeal compartment of the relapse was an aneuploid cell clone with a FCM DNA index of 1.42 and 1.44, respectively. The extralaryngeal compartment showed a shift featuring a DNA index of 2.78. In the primary tumor and in both compartments of the recurrence there was an identical pattern of complex chromosomal imbalances as detected in CGH (CGH karyotype: rev ish enh [8q24.2-q24.3, 10q26.1-q26.3, 11q24-q25, 12q24.2-q23.33,X], dim [4q, 13q14.3-q31], amp[1p36.1-p36.2]). Hence, the recurrence was not associated with further gains and losses of chromosomal material. However, in the anterior part of the recurrence, the aneuploid tumor cell genome had completely doubled, obviously due to endoreduplication. Immunohistochemical analysis of several cell-cycle regulators revealed altered expression of checkpoint proteins, pointing to a complex disturbance in cell-cycle regulation. 相似文献
18.
Obwaller A Duchêne M Bruhn H Steipe B Tripp C Kraft D Wiedermann G Auer H Aspöck H 《Parasitology research》2001,87(5):383-389
Myosins from nematode parasites elicit strong humoral and cellular immune responses and have been investigated as vaccine candidates. In this study we cloned and sequenced a cDNA coding for myosin heavy chain from Toxocara canis, a nematode parasite of canids which may also infect humans and cause various unspecific symptoms. To determine the major antigenic regions the myosin heavy chain was systematically dissected into ten overlapping recombinant fusion polypeptides which were purified by metal chelate chromatography. Single fragments were then tested for their IgG reactivity in sera from toxocarosis patients and healthy probands. Two regions, one region at the mid to carboxy-terminal end of the head domain and one region in the rod domain, were identified as major antigens, which in combination were positive with 86% of the sera. The other domains were less reactive. This shows that the patients' IgG reactivity was not directed evenly against all parts of the molecule, but was rather clustered in few regions. 相似文献
19.
Barbara M. Brker Michael S. Kraft Ulricke Klauenberg Franoise Le Deist Jean-Pierre de Villartay Bernhard Fleckenstein Bernhard Fleischer Edgar Meinl 《European journal of immunology》1997,27(11):2774-2780
Signaling via the T cell receptor (TCR)/CD3 complex of pre-activated T cells induces apoptosis. Such an activation-induced cell death (AICD) is thought to play an important role in the regulation of cellular immune responses. In this study we analyzed pathways of AICD by using human T cells transformed by Herpesvirus saimiri. These growth-transformed T cells show the phenotype of activated mature T cells and continue to express a functionally intact TCR. We show that human H. saimiri-transformed T cell clones readily undergo cell death upon signaling via the TCR/CD3 complex or via phorbol 12-myristate 13-acetate (PMA) + ionomycin. The AICD in H. saimiri-transformed T cells was detectable a few hours after activation and it was not affected by the presence of interleukin (IL)-2 or by anti-CD4 cross-linking. However, AICD required tyrosine phosphorylation, since it could be blocked by herbimycin A. Cyclosporin A (CsA) did not block the development of AICD, but other consequences of activation in H. saimiri-transformed T cells like the production of interferon-γ. Surprisingly, the development of AICD was not reduced by neutralizing antibodies to tumor necrosis factor (TNF)-α or blocking antibodies directed to CD95 (Fas, APO-1), although H. saimiri-transformed T cells were sensitive to CD95 ligation. To confirm that this form of AICD is really independent of CD95, we have established an H. saimiri-transformed T cell line from a patient with a homozygous deletion in the CD95 gene. This CD95-deficient T cell line was as sensitive to AICD as other CD95-expressing H. saimiri-transformed T cells. In conclusion, we describe here a type of AICD in H. saimiri-transformed T cells that is independent of CD95 and TNF-α, not sensitive to CsA, but requires tyrosine phosphorylation. This system should be useful for the investigation of CD95-independent forms of AICD. 相似文献
20.