全文获取类型
收费全文 | 2780篇 |
免费 | 162篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 74篇 |
妇产科学 | 62篇 |
基础医学 | 490篇 |
口腔科学 | 103篇 |
临床医学 | 236篇 |
内科学 | 541篇 |
皮肤病学 | 33篇 |
神经病学 | 285篇 |
特种医学 | 114篇 |
外科学 | 224篇 |
综合类 | 19篇 |
预防医学 | 259篇 |
眼科学 | 30篇 |
药学 | 218篇 |
中国医学 | 22篇 |
肿瘤学 | 250篇 |
出版年
2024年 | 2篇 |
2023年 | 36篇 |
2022年 | 100篇 |
2021年 | 139篇 |
2020年 | 89篇 |
2019年 | 89篇 |
2018年 | 98篇 |
2017年 | 84篇 |
2016年 | 96篇 |
2015年 | 79篇 |
2014年 | 135篇 |
2013年 | 157篇 |
2012年 | 254篇 |
2011年 | 243篇 |
2010年 | 130篇 |
2009年 | 131篇 |
2008年 | 183篇 |
2007年 | 184篇 |
2006年 | 167篇 |
2005年 | 139篇 |
2004年 | 86篇 |
2003年 | 117篇 |
2002年 | 97篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1995年 | 13篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有2969条查询结果,搜索用时 15 毫秒
11.
Maria Rosaria Raspollini Gianni Amunni Alessandro Villanucci Francesca Castiglione Duccio Rossi Degl'Innocenti Gianna Baroni Milena Paglierani Gian Luigi Taddei 《Applied immunohistochemistry & molecular morphology》2006,14(2):181-186
The bcl-2 protein is a membrane protein involved in prolonging cell survival by inhibiting apoptosis. The HER-2 oncogene, which is located on chromosome 17 and encodes for a tyrosine-kinase growth factor receptor, is amplified and HER-2/neu is overexpressed in 25% to 30% of breast carcinomas. The authors analyzed the bcl-2 expression and the bcl-2 gene and HER-2/neu overexpression and amplification in FIGO stage IIIC, serous, G3, ovarian carcinomas obtained from living patients who had no evident disease 5 years after primary treatment compared with ovarian carcinomas obtained from patients, matched for stage, grade of differentiation, and treatment, who had died of progression of disease no later than 2 years after primary treatment. bcl-2 overexpression was statistically correlated with progression of disease during first-line chemotherapy (P=0.021). The HER-2/neu status was found not to correlate with progression of disease during first-line chemotherapy. Both bcl-2 and HER-2/neu expression were not statistically associated with the clinical outcome of ovarian cancer patients. Gene amplification of the HER-2/neu chromosome 17 was found in all the HER-2/neu, 3+ score, positive-staining ovarian carcinomas. None of the analyzed samples revealed a translocation t(14;18)(q32;q21) in the bcl-2 gene. The knowledge of additional prognostic or even predictive factors, such as bcl-2 expression, in patients with advanced ovarian carcinoma before the primary chemotherapeutic treatment may help in the management of patients who require a more tailored treatment. In addition, the gene amplification of the HER-2/neu suggests that HER-2 is a potential target for treatment in ovarian cancer. 相似文献
12.
Apoptotic defects and impaired clearance of cellular debris are considered key events in the development of autoimmunity,
as they can contribute to autoantigen overload, and may initiate an autoimmune response. The pentraxins are a group of highly
conserved proteins including the short pentraxins, C-reactive protein (CRP) and serum amyloid-P (SAP), and the long pentraxin-3
(PTX3), which are all involved in innate immunity and in acute-phase responses. Mannan-binding lectin (MBL) is an activator
of the complement system, and Apolipoprotein A-1 (Apo A-1) is pivotal in the cholesterol homeostasis and has anti-inflammatory
properties. In addition to their role in innate immunity and inflammation, each of these five proteins participates in the
removal of damaged and apoptotic cells. In this review, we discuss the clinical significance of different levels of these
proteins, their role in the induction or protection from autoimmunity, and the presence of specific autoantibodies against
them in the different autoimmune diseases. 相似文献
13.
Miodrag ?oli? Nada Pejnovi? Milena Kataranovski Ljiljana Popovi? Sonja Ga?I? Aleksandar Duji? 《Clinical & developmental immunology》1992,2(2):151-160
Rat thymic epithelial cells (TEC) in long-term culture were characterized by
anticytokeratin monoclonal antibodies (mAbs) and electron microscopy. Phenotypic
analysis performed by a large panel of mAbs showed that the highest percentage of
these cells was of the subcapsular/medullary type.
Recombinant rat interferon (IFN)-gamma up-regulated class-I and class-II MHC
expression by TEC in culture as confirmed by immunohistochemistry and flow
cytometry, but did not significantly alter other cell markers. TEC supernatants of IFN-gamma-
treated cultures showed higher interleukin-6 (IL-6) activity, compared to the
control, as determined by proliferation of the IL-6-sensitive B9-cell line. Increased IL-6
activity was probably not a consequence of increased TEC number in IFN-gammatreated
cultures because IFN did not significantly stimulate TEC proliferation in vitro. In
contrast, IL-6 significantly stimulated TEC proliferation, indicating that this cytokine is
not only a regulatory molecule for T-cell proliferation, but could also be an autocrine
growth factor for thymic epithelium. 相似文献
14.
15.
Tadech Boonpiyathad Willem van de Veen Oliver Wirz Milena Sokolowska Beate Rückert Ge Tan Atik Sangasapaviliya Panitan Pradubpongsa Rattanaporn Fuengthong Pattarawat Thantiworasit Sunee Sirivichayakul Kiat Ruxrungtham Cezmi A. Akdis Mübeccel Akdis 《The Journal of allergy and clinical immunology》2019,143(3):1077-1086.e10
16.
Ricca V Nacmias B Boldrini M Cellini E di Bernardo M Ravaldi C Tedde A Bagnoli S Placidi GF Rotella CM Sorbi S 《Neuroscience letters》2004,365(2):92-96
Various studies have evaluated the possible role of the -1438G/A polymorphism within the 5-HT2A receptor gene in the susceptibility to Eating Disorders (EDs). One hundred and forty-eight ED patients (EDp) and 89 control subjects were interviewed by means of the Eating Disorder Examination (EDE) and analyzed for distribution of the -1438G/A polymorphism. Patients with the AA genotype suffering from Anorexia Nervosa and Bulimia Nervosa showed higher Weight and Shape Concern (P = 0.003 and P = 0.010, respectively) scores and greater overall severity of the ED psychopathology (EDE total score) (P = 0.012). The obtained preliminary data suggest the use of dimensional psychopathological measures in ED genetic studies. 相似文献
17.
Šimurda Jiří Šimurdova Milena Braveny Pavel Šumbera Josef 《Pflügers Archiv : European journal of physiology》1976,362(3):209-218
1. | The relationship of the contractile response of cat papillary muscles and of the slow inward current, recorded under voltage clamp conditions (single sucrose gap), has been studied. The preparations were driven at a rate of 30 per min at 31° C. Both variables were recorded during a train of 7 identical clamp depolarizations (for 1 s from resting potential to –15 to +40 mV). The contractility increased severalfold and reached the steady state within 5–6 consecutive depolarizations. |
2. | The voltage-dependence of slow inward current was confirmed: maximum was found at depolarizations near 0 mV. On repetition of clamp pulses the slow current gradually diminished in amplitude and was more slowly activated and inactivated. The shift of the current-voltage curve indicated a decrease of the reversal potential. |
3. | Under non-steady state conditions the amplitude of the slow current was found to correlate closely with the magnitude of the contractile response at any given level of depolarization. The relation was linear with negative slope. The largest contractile response was not found at voltages which elicited maximum slow current. |
4. | The progressive decrease of the slow current during repetition of voltage clamp depolarizations is not significantly affected by inadequate time for recovery of slowly changing conductances, since it occurs also at stimulation frequency 15 per min and the slow current remains virtually unaltered after 20 s period of quiescence. |
5. | The course of total ionic current during phase 1 and 2 of action potential was reconstructed from a family of current curves obtained as a response to clamp depolarizations to various voltages, respecting the contractility-dependence of the current. The resulting course was correlated with the first derivative of action potential. A general conformity was ascertained. |
6. | The correlation of slow inward current with action potential configuration indicates that the rate of its activation determines the depth of the notch separating spike and plateau, its magnitude determines the voltage of the plateau phase and its rate of inactivation affects repolarization. |
7. | It is concluded that the described simultaneous changes of mechanical and electrical phenomena might be due to increased [Ca]i, which is responsible for more intense activation of the contractile proteins on the one hand, and decreased driving force of the slow inward current, carried by Ca ions, on the other. |
18.
Anders Rinnov Nielsen Remi Mounier Peter Plomgaard Ole Hartvig Mortensen Milena Penkowa Tobias Speerschneider Henriette Pilegaard Bente Klarlund Pedersen 《The Journal of physiology》2007,584(1):305-312
The cytokine interleukin-15 (IL-15) has been demonstrated to have anabolic effects in cell culture systems. We tested the hypothesis that IL-15 is predominantly expressed by type 2 skeletal muscle fibres, and that resistance exercise regulates IL-15 expression in muscle. Triceps brachii, vastus lateralis quadriceps and soleus muscle biopsies were obtained from normally physically active, healthy, young male volunteers ( n = 14), because these muscles are characterized by having different fibre-type compositions. In addition, healthy, normally physically active male subjects ( n = 8) not involved in any kind of resistance exercise underwent a heavy resistance exercise protocol that stimulated the vastus lateralis muscle and biopsies were obtained from this muscle pre-exercise as well as 6, 24 and 48 h post-exercise. IL-15 mRNA levels were twofold higher in the triceps (type 2 fibre dominance) compared with the soleus muscle (type 1 fibre dominance), but Western blotting and immunohistochemistry revealed that muscle IL-15 protein content did not differ between triceps brachii, quadriceps and soleus muscles. Following resistance exercise, IL-15 mRNA levels were up-regulated twofold at 24 h of recovery without any changes in muscle IL-15 protein content or plasma IL-15 at any of the investigated time points. In conclusion, IL-15 mRNA level is enhanced in skeletal muscles dominated by type 2 fibres and resistance exercise induces increased muscular IL-15 mRNA levels. IL-15 mRNA levels in skeletal muscle were not paralleled by similar changes in muscular IL-15 protein expression suggesting that muscle IL-15 may exist in a translationally inactive pool. 相似文献
19.
Penkowa M Keller P Keller C Hidalgo J Giralt M Pedersen BK 《Experimental physiology》2005,90(4):477-486
Exercise induces free oxygen radicals that cause oxidative stress, and metallothioneins (MTs) are increased in states of oxidative stress and possess anti-apoptotic effects. We therefore studied expression of the antioxidant factors metallothionein I and II (MT-I + II) in muscle biopsies obtained in response to 3 h of bicycle exercise performed by healthy men and in resting controls. Both MT-I + II proteins and MT-II mRNA expression increased significantly in both type I and II muscle fibres after exercise. Moreover, 24 h after exercise the levels of MT-II mRNA and MT-I + II proteins were still highly increased and the MT-II mRNA expression reached a 15-fold increase. As expected, immunohistochemical detection of malondialdehyde (MDA) and nitrotyrosine (NITT) showed that formation of free radicals and oxidative stress were clearly increased in exercising muscle peaking shortly after the end of exercise in both type I and II muscle fibres. This is the first report demonstrating that MT-I + II are significantly induced in human skeletal muscle fibres following exercise. As MT-I + II are antioxidant factors that protect various tissues during pathological conditions, the MT-I + II increases post exercise may represent a mechanism whereby contracting muscle fibres are protected against cellular stress and injury. 相似文献
20.
Martini L Fini M Giavaresi G Torricelli P de Pretto M Rimondini L Giardino R 《Artificial cells, blood substitutes, and immobilization biotechnology》2003,31(4):449-466
Over the past decade extracorporeal shock-wave therapy (ESWT) has been increasingly applied to orthopaedic and musculoskeletal pathologies, the aim of this study was to assess how the energy density of the shock waves and the number of impulses affect viability, differentiation and synthetic activity of osteoblasts. Primary sheep osteoblasts cultures were treated with ESWT with an electro-hydraulic shock wave generator by selecting three different energy levels (14-21-28 kV corresponding at 0.15-0.31-0.40 mJ/mm2) and two different total numbers of impulses (500, 1000) for each level. At the end of treatment, cell counts and viability were recorded. Cells were then cultivated for 48 hours starting from a concentration of 1 x 10(4) cells/ml. The biological activity and viability were evaluated at 24 and 48 hours after treatment. No cytodestructive effects were observed in Group A, while a cytodestructive effect of ESWT was seen in cultures receiving the highest energy treatments. The different shock wave treatment induced differences in MTT assays after 24 and 48 hours, in particular the highest level showed a detrimental effect on cell respiration at both experimental times as compared to the Control Group and the protein metabolism was generally depressed by ESWT with impulses at the highest energy level. After 24 hours such effect further increased with the growing number of impulses. The lowest energy level appeared to significantly improve the metabolic parameter in primary cell cultures as compared to controls when 500 impulses were selected. The current study has demonstrated that one of the most important aspects to be considered is not the total number of impulses used but the energy level of the shock waves, thus confirming that ESWT has a dose-dependent effect on cells. 相似文献