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1.
2.
Gautham Kulamarva Mark Wilbourn Rajiv Anand Constantinos Mourouzis Anne V Spedding Peter A Brennan 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(2):240-242
Chordoma is a rare tumor, arising from notochord remnants, which usually occurs in the axial skeleton and rarely metastasizes. Although there have been 3 previous reports of metastatic disease to the facial bones from sacrococcygeal chordoma, this is the first to describe spread to the mandible from a vertebral primary chordoma. 相似文献
3.
Although tumour vasculature constitutes a biological factor playing a crucial role in the radiation response of tumours, the current procedures of assessment are semiquantitative, typically employing visual examination of stained histological material. Such techniques are also time consuming, and inefficient of extracting essential information on the vascular network. Image analysis has yet to contribute significantly in this direction, and most studies to date focus on blood vessel segmentation through empirical, user-selected thresholds. The present paper proposes an alternative segmentation approach, based on a probabilistic relaxation algorithm, applied in microscopic images of stained tissues. After image partitioning various information is obtained, such as vascular domains and geometrical characteristics of vessels. 相似文献
4.
Immobilisation induces bone loss. Evidence from studies in animals and healthy humans that were immobilised for a limited time indicates that, in general, bone mass may be restored even in adults. Following conservative management of partial tears of the anterior cruciate ligament (ACL), bone loss is often negligible (2-3%). After surgical reconstruction, however, there is greater bone loss (15-20%), with little or no recovery. Bones adapt to the stresses they experience. Also, the largest forces in the musculoskeletal system arise from muscle pull. Tendons transmit these forces. Many surgical techniques for ACL reconstruction use autologous tendon grafts. We hypothesise that tissue harvesting causes weakening of the formerly intact tendon, which, in turn, leads to reduced muscle pull and subsequent bone loss in those parts of the bone that are loaded by the tendon. If our hypothesis holds true, it may change patients' and surgeons' choice of management. Clinical follow-up should assess the functional result with greater scrutiny, possibly including the assessment of bone mineral content. This may be particularly important since there is accumulating evidence that a decrease in bone mineral density (BMD) preceedes, and hence may be a cause of, osteoarthritis. 相似文献
5.
Ultrasonographic assessment of human skeletal muscle size 总被引:7,自引:0,他引:7
The measurement of human muscle size is essential when assessing the effects of training, disuse and ageing. The considered gold standard for cross-sectional area measurements of muscle size is magnetic resonance imaging (MRI). However, MRI is costly and often inaccessible. The aim of the present study was to test the reproducibility and validity of a more accessible alternative method using ultrasonography (ULT). We examined the cross-sectional areas in the vastus lateralis muscle of six individuals. Axial-plane ULT scans were taken at given levels along the entire muscle length. The ULT scanning was repeated on different days (reliability) and validated against MRI-based measurements. Mean intraclass correlation coefficients were 0.998 for the reliability of ULT and 0.999 for the validity of ULT against MRI. The coefficient of variation values for cross-sectional area measurements assessed by six different experimenters were 2.1% and 0.8% for images obtained with ULT and MRI, respectively. The ULT method is a valid and reliable alternative tool for assessing cross-sectional areas of large individual human muscles. The present findings justify the application of the ULT method for the detection of changes throughout large muscles in response to training, disuse or as a consequence of sarcopenia. 相似文献
6.
Petros Dafniotis Eleni Karayianni Constantinos Panayiotou 《Macromolecular chemistry and physics.》1989,190(5):1103-1117
A most general formalism based on the Lattice-Fluid theory of polymer solutions is presented for multicomponent mixtures of random copolymers which may consist of any number of different types of monomers. Particular emphasis is given to the phase stability in these mixtures. Equations for the spinodals and the critical points are presented. The formalism is subsequently applied to a number of interesting cases of ternary (co)polymer mixtures such as: mixtures of three random copolymers with the same monomers A and B but in different proportions (A B + A B + A B) mixtures of homopolymers Am and Bn with the random copolymer Ai Bj, and mixtures of the random copolymers (A B + A B + A C). The effect of temperature on the phase behavior of these systems is discussed. The agreement of theoretical predictions with available experimental information is satisfactory. Because of its simplicity, the model may be used as a tool for studying multicomponent mixtures exhibiting lower or upper critical solution temperature behavior. 相似文献
7.
Constantinos G. Panayiotou 《Macromolecular chemistry and physics.》1987,188(11):2733-2743
The lattice-fluid theory of polymer solutions, previously applied to homopolymer-solvent and homopolymer-homopolymer mixtures, is now extended to random copolymer mixtures. A generalized, though simple, formalism is presented which is valid for binary copolymer mixtures, each copolymer having any number of different monomeric units (groups). Mixtures of a homopolymer with a random copolymer are treated as a special subcase. Particular emphasis is given to the phase stability of copolymer mixtures. Equations for the spinodal and the critical point are presented. The model is applied satisfactorily to various cases which attracted special attention in recent studies on the miscibility of copolymer mixtures. 相似文献
8.
Adil M. Al-Nahhas Seishi Jinnouchi Constantinos Anagnostopoulos Wolfgang Hirsch Tom Heary V. Ralph McCready 《European journal of nuclear medicine and molecular imaging》1995,22(2):148-153
Benign myocardial uptake of technetium-99m labelled phosphates, not related to cardiac or metabolic disorders, has been documented except in the case of99mTc-methylene diphosphonate (MDP). The aim of this study was to assess the frequency of myocardial uptake and its possible association with malignant tumours in general and prostatic carcinoma in particular. We reviewed bone scintigrams performed with either99mTc-hydroxydiphosphonate (HDP) or99mTc-MDP over a period of more than 2 years for all patients with prostatic carcinoma and a matching group of patients suffering from other malignant and non-malignant disorders. A total of 965 scintigrams of 812 patients (males=559, females=253; age range 50–91 years, average age 69.2 years) were reviewed. Increased myocardial uptake was detected in 19 scintigrams (MDP=13, HDP=6) of 18 patients (17 males, one female). Most of the male patients with increased myocardial uptake had prostatic carcinoma (13/17) and were over 80 years of age (12/17). All patients were free of any cardiac or noncardiac disorder that might account for such uptake. When scintigraphy was repeated in the same patient, the uptake of99mTc-HDP was more diffuse and of higher grade than that of99mTc-MDP Benign myocardial uptake of99mTc-MDP is more common than previously thought. Although uptake of radiophosphates is attributed to asymptomatic atherosclerotic changes associated with old age, a strong association with prostatic carcinoma exists which may indicate variations in the bone: soft tissue affinity of different MDP complexes. 相似文献
9.
Constantinos Anagnostopoulos Mark G. Gunning Dudley J. Pennell Robin Laney Haralambos Proukakis S. Richard Underwood 《European journal of nuclear medicine and molecular imaging》1996,23(8):909-916
We have validated ECG-gated emission tomography using technetium-99m methoxyisobutylisonitrile for the assessment of regional ventricular function by comparing it with cine magnetic resonance imaging (MRI). Gated tomography was performed at rest in 24 patients referred for myocardial perfusion imaging [17 males and seven females with a mean age of 58 years, nine of whom had had a previous myocardial infarction (MI)]. Scores were assigned to each of nine myocardial segments for wall motion and for thickening. Cine MRI was analysed in an identical fashion. Four out of 216 (2%) segments were uninterpretable by gated tomography because of inadequate tracer uptake. In eight patients without coronary artery disease (CAD), wall motion and thickening were normal by both methods. Gated tomography showed abnormal wall motion or thickening in all patients with previous MI and in five of seven patients with CAD but no prior MI. Association between wall motion and thickening was good (r
s=0.86). Overall, there was good agreement between gated tomography and MRI for both wall motion (178/212 segments, =0.66) and wall thickening (184/212 segments, =0.69). In segments with severely reduced perfusion, however, there was poorer agreement (=0.31). Interobserver and intraobserver agreement was high ( from 0.61 to 0.78). Thus, in patients investigated for CAD, there is good overall agreement between gated tomography and MRI but the agreement is lower in segments with severe perfusion defects. 相似文献
10.
Constantinos K. Zacharis Paraskevas D. TzanavarasMaria Notou Anastasia ZotouDemetrius G. Themelis 《Journal of pharmaceutical and biomedical analysis》2009
A micellar electrokinetic chromatography (MEKC) method has been developed and validated for the determination of nimesulide related compounds in pharmaceutical formulations. Electrophoretic separation of six European Pharmacopoeia (EP) impurities (A–F) was performed using a fused silica capillary (Leff. = 50 cm, Ltot. = 57 cm, 50 μm i.d.) with a background electrolyte (BGE) containing 25 mM borate buffer (pH 9.5), 30 mM sodium dodecyl sulphate and φ = 3% (v/v) acetonitrile. The influence of several factors (surfactant and buffer concentration, pH, organic modifier, applied voltage, capillary temperature and injection time) was studied. The method was suitably validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. The calibration curves obtained for the six compounds were linear over the range 5–12 μg ml−1 (0.05–0.12%). The relative standard deviations (sr) of intra- and inter-day experiments were less than 5.0%. The detection limits ranged between 0.7 and 1.6 μg ml−1 depending on the impurity. The proposed method was applied successfully to the quantification of nimesulide impurities in its pharmaceutical formulation. 相似文献