全文获取类型
收费全文 | 15724篇 |
免费 | 1043篇 |
国内免费 | 280篇 |
专业分类
耳鼻咽喉 | 382篇 |
儿科学 | 204篇 |
妇产科学 | 288篇 |
基础医学 | 2722篇 |
口腔科学 | 300篇 |
临床医学 | 1269篇 |
内科学 | 3145篇 |
皮肤病学 | 451篇 |
神经病学 | 1185篇 |
特种医学 | 1067篇 |
外科学 | 2098篇 |
综合类 | 86篇 |
现状与发展 | 3篇 |
一般理论 | 10篇 |
预防医学 | 611篇 |
眼科学 | 431篇 |
药学 | 1320篇 |
中国医学 | 153篇 |
肿瘤学 | 1322篇 |
出版年
2024年 | 12篇 |
2023年 | 133篇 |
2022年 | 369篇 |
2021年 | 663篇 |
2020年 | 270篇 |
2019年 | 442篇 |
2018年 | 526篇 |
2017年 | 411篇 |
2016年 | 613篇 |
2015年 | 875篇 |
2014年 | 956篇 |
2013年 | 1048篇 |
2012年 | 1579篇 |
2011年 | 1426篇 |
2010年 | 852篇 |
2009年 | 718篇 |
2008年 | 895篇 |
2007年 | 966篇 |
2006年 | 783篇 |
2005年 | 640篇 |
2004年 | 518篇 |
2003年 | 467篇 |
2002年 | 380篇 |
2001年 | 299篇 |
2000年 | 246篇 |
1999年 | 181篇 |
1998年 | 94篇 |
1997年 | 66篇 |
1996年 | 47篇 |
1995年 | 55篇 |
1994年 | 46篇 |
1993年 | 42篇 |
1992年 | 47篇 |
1991年 | 47篇 |
1990年 | 44篇 |
1989年 | 44篇 |
1988年 | 36篇 |
1987年 | 35篇 |
1986年 | 21篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1973年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Hyung-Eun Yoon Kenjiro Fukuhara Toshiya Michiura Minoru Takada Masami Imakita Kentaro Nonaka Kazuhiro Iwase 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(1):22-28
OBJECTIVES: For the histological diagnosis of small lung cancers of 10 mm or less in diameter (< or =10), resection by video-assisted thoracic surgery (VATS) with computed tomography (CT)-guided marking is feasible. One problem is that a small number of these pulmonary nodules are malignant. We retrospectively analyzed CT images of pulmonary nodules to find better criteria to select candidates for resection among patients with small pulmonary nodules. METHODS: Ninety-four patients with indeterminate peripheral pulmonary nodules underwent wedge resection by VATS. High-resolution CT using a 1.25 mm slice included the area of lesions. Nodules were classified by size (< or =10, 11 to 20, >20 mm) and whether they had a ground-glass opacity (GGO) component. RESULTS: The histology of all 94 nodules showed 52 primary lung cancers, 6 metastatic tumors, 5 benign tumors, 8 intrapulmonary lymph nodes, and 23 inflammatory nodules. Ninety-three percent of nodules larger than 20 mm, 75% of nodules 10 to 20 mm, and 43% of nodules < or =10 mm were malignant. Introducing a classification according to GGO component to nodules, malignancy was detected in 88% of nodules with a GGO component and in 30% of nodules without a GGO component among nodules < or =10 mm. Nodules < or =10 mm with a GGO component showed a statistically significant (p < 0.01) correlation with malignancy. CONCLUSIONS: Pulmonary nodules < or =10 mm with GGO should be considered to have a high possibility of malignancy and to be candidates for resection by VATS. 相似文献
42.
Comparison of functional results with navigation-assisted minimally invasive and conventional techniques in bilateral total knee arthroplasty. 总被引:1,自引:0,他引:1
This study was undertaken to compare the clinical and radiological results achieved using navigation-assisted minimally invasive surgery (NA-MIS) and conventional (CON) techniques in 42 bilateral total knee arthroplasty (TKA) patients with a minimum follow-up of one year. Clinical evaluations were performed using range of motion (ROM), Hospital for Special Surgery (HSS) scores, and Western Ontario and McMaster University (WOMAC) scores (pain, functional, and total) at 3, 6 and 9 months and one year postoperatively. Patients' subjective preferences and radiological indices, including mechanical axis and coronal inclinations of the prostheses, were compared at one year postoperatively. NA-MIS TKA yielded better HSS and WOMAC total scores than CON TKA up to six months, and a better WOMAC pain score up to 9 months. However, these differences were not significant at one year postoperatively. ROM was comparable in both groups at all times, but more patients preferred the NA-MIS side to the CON side. Radiological results showed no differences in mean values between the two surgical groups, although the NA-MIS group contained fewer outliers than the CON group. In conclusion, NA-MIS TKA was associated with better clinical results up to 6 or 9 months after surgery, giving more accurate leg alignment than CON TKA. 相似文献
43.
Yu Ri An Jeong Han Seung Jun Kim Moon-Ju Oh Jung-Hwa Oh Seok-Joo Yoon Seung Yong Hwang 《Toxicology and Environmental Health Sciences》2010,2(4):245-250
It is important to acknowledge the harmful effects of environmental chemicals in human’s lives. The toxic effects of Diethylstilbestrol (DES), one of the endocrine-disrupting chemicals (EDCs), have been documented in many studies. As expected, DES affect male gendal hormone as well as female’s; therefore, epigenetic study should be considered. In this study, microarray technology was used to study harmful effects on the level of genomics, and here, two types of microarray chips- the Agilent mouse genome 4 × 44 K array for gene expression profiling and the Agilent mouse miRNA v13 for miRNA expression profiling-was used to study the relation between gene and miRNA expression profiles. As a result, we identified 4 miRNAs (miR 203, 350, 421, and 466i) that were similarly expressed at 3 hrs and 24 hrs of DES treat times. Twenty one genes matched between predicted target for 4 miRNAs and 118 genes expressed similarly. These genes have functions related to cell differentiation and cell cycle. Therefore, DES affects cellular function and induces toxicity in TM4 cells. In future studies, it is necessary to find more related functions and mechanisms of DES in the system. 相似文献
44.
45.
Kyoung-Ah Kim Min-Jung Kim Ji-Young Park Ji-Hong Shon Young-Ran Yoon Sang-Seop Lee Kwang-Hyeon Liu Jin-Ho Chun Myung-Ho Hyun Jae-Gook Shin 《Drug metabolism and disposition》2003,31(10):1227-1234
The stereoselective metabolism of lansoprazole enantiomers was evaluated by incubation of human liver microsomes and cDNA-expressed cytochrome p450 (p450) enzymes to understand and predict their stereoselective disposition in humans in vivo. The intrinsic clearances (Clint) of the formation of both hydroxy and sulfone metabolites from S-lansoprazole were 4.9- and 2.4-fold higher than those from the R-form, respectively. The sums of formation Clint of both metabolites were 13.5 and 57.3 microl/min/mg protein for R- and S-lansoprazole, respectively, suggesting that S-lansoprazole would be cleared more rapidly than the R-form. The p450 isoform selective inhibition study in liver microsomes, and the incubation study of cDNA-expressed enzymes, demonstrated that the stereoselective sulfoxidation is mediated by CYP3A4 and that the hydroxylation is mediated by CYP2C9 and CYP3A4 as well as by CYP2C19. Total Clint values of hydroxy and sulfone metabolite formation catalyzed by all these p450 enzymes were consistently higher for S-lansoprazole than for the R-form. The CYP3A4 produced the greatest difference of Clint between S- and R-enantiomers, mainly due to a difference of sulfoxidation metabolism (Clint 76.5 versus 10.8 microl/min/nmol of p450, respectively), whereas CYP2C19-catalyzed hydroxylation resulted in a minor difference of Clint between S- and R-enantiomers (179.6 versus 143.3 microl/min/nmol of p450, respectively). However, the affinity of CYP2C19 on hydroxylation was 5.7-fold higher for S-enantiomer than for the R-form (Km 2.3 versus 13.1 microM), suggesting that the role of CYP2C19 on stereoselective hydroxylation would be more prominent at concentrations around the usual therapeutic level. These findings suggest that both CYP2C19 and CYP3A4 are major enzymes contributing to the stereoselective disposition of lansoprazole, but stereoselective hydroxylation of lansoprazole enantiomers is mainly influenced by CYP2C19, especially at the usual therapeutic doses. 相似文献
46.
BACKGROUND: The recent introduction of urea sensors for dialysis monitoring
has made possible new approaches to urea kinetic modelling. In this study
we show how the equilibrated postdialysis urea concentration (Ceq) and Kt/V
corrected for double-pool urea kinetics (Kt/Vdp) can be accurately
determined using an on-line sensor providing a continuous measure of blood
water urea. A modification of the Smye constant volume double-pool theory
led to the following equations for Ceq and Kt/Vdp [formula: see text] where
Cpre is the blood concentration measured at the start of dialysis, t is the
length of the dialysis session (in min) and S(ex) is the constant slope of
the blood urea logarithm concentration decline following development of the
intercompartmental urea concentration gradient in the first 30-60 min of
dialysis. METHODS: These equations were tested in 11 patients undergoing
165-240 min of paired filtration dialysis with continuous monitoring of
blood urea concentration. Cpre was determined as the plateau concentration
during a preliminary period of 15-20 min of slow isolated ultrafiltration.
S(ex) was accurately determined from linear regression applied to the urea
sensor data from the 80-min point to the end of dialysis. RESULTS: Ceq and
Kt/Vdp determined from the above equations compared closely to values
determined from 25-40 min of urea rebound monitoring with the urea sensor:
10.6 +/- 3.0 versus 10.8 +/- 2.7 mmol/l (mean +/- SD) for Ceq and 1.21 +/-
0.24 versus 1.18 +/- 0.20 for Kt/Vdp, compared to single-pool values of
Kt/V = 1.34 +/- 0.23. CONCLUSION: This technique may be readily programmed
into on-line urea monitors to provide current and extrapolated values of
Ceq and Kt/Vdp from about the first hour of dialysis.
相似文献
47.
Natural killer/T-cell lymphoma (NKTL) and peripheral T-cell lymphomas (PTCL) are prevalent in the Asian population and exhibit a high association with the Epstein-Barr virus (EBV). Moreover, differentiation of these two groups is often difficult and problematic. We investigated 35 cases of NKTL (22 nasal cases and 13 extranasal cases) and 30 cases of PTCL in terms of their clinical features, immunohistology, EBV positivity, EBV strain-type polymorphism and latent membrane protein 1 (LMP1) deletion variant distribution. Eighteen cases (82%) of nasal NKTL and seven (54%) of extranasal NKTL showed EBV positivity by EBV in situ hybridization. Fifteen cases (50%) of PTCL revealed EBV positivity. EBV strain type A was predominant in NKTL (18:5), and EBV strain types A and B were distributed evenly in PTCL (6:6). EBV-positive patients had significantly shorter survival than EBV-negative patients (P < 0.05), and EBV positivity correlated with advanced clinical stage (P < 0.05). Patients harboring type A EBV showed slightly poorer prognoses than those having type B, though it was not obviously statistically different (P = 0.07). The LMP1 deletion variant was prevalent in both NKTL (three wild-type LMP1, 15 deletion variants) and PTCL (three wild-type LMP1, eight deletion variants, two coexistent forms) patients, but did not have prognostic impact. Our results indicate that EBV acts as a negative prognostic factor in NKTL and PTCL, and that the intrinsic properties of a specific viral strain might influence the clinical behavior of these diseases. 相似文献
48.
Darai E; Leblanc M; Walker-Combrouze F; Bringuier AF; Madelenat P; Scoazec JY 《Human reproduction (Oxford, England)》1998,13(5):1346-1352
We evaluated the immunohistochemical expression of cadherins and CD44
variants in 20 endometriomas, 20 cystadenomas, 20 borderline ovarian
tumours as well as 20 ovarian carcinomas, and the serological and cystic
fluid concentrations of soluble E-cadherin and soluble CD44 standard
(sCD44sdt) in 20 endometriomas, 20 cystadenomas, six borderline and 11
carcinomas of the ovary. In endometriomas, immunostaining of E- and
N-cadherin was negative (20 and 30% respectively). CD44 H, v3 and v6
immunostaining were detected in 63, 10 and 40% respectively. A difference
in immunostaining for E-cadherin was found between endometriomas and
cystadenomas (P < 0.001) and for N- cadherin between endometriomas and
carcinomas (P < 0.001). A difference in CD44H immunostaining was
observed between endometriomas and cystadenomas (P < 0.035) but not with
borderline ovarian tumours and carcinomas. No difference in serum
concentrations of soluble E- cadherins and CD44 standard was found between
the four groups of tumours. Cystic fluid concentrations of E-cadherin were
lower in endometriomas than in borderline tumours and ovarian carcinomas (P
< 0.001). High concentrations of soluble CD44 standard cystic fluid were
found in endometriomas than in other ovarian cysts. Endometriomas and
borderline tumours share alterations of cadherins and CD44 isoforms which
may help in the understanding of the aggressive and invasive potentials of
endometriotic cells.
相似文献
49.
Combined effects of inhaled nitric oxide and a recruitment maneuver in patients with acute respiratory distress syndrome 总被引:1,自引:0,他引:1
Nitric oxide (NO) inhalation therapy has been employed in the management of acute respiratory distress syndrome (ARDS), in order to improve oxygenation. Several factors have been implicated as being responsible for the action of inhaled NO. Alveolar recruitment methods, such as prone positioning and a sufficient positive end expiratory pressure (PEEP), have been identified as having a positive impact on the NO response. A Recruitment maneuver (RM) was introduced for the treatment of ARDS, along with a lung protective strategy. Here, we hypothesized that a RM may further augment the oxygenation of patients treated with NO inhalation. Therefore, the effects of the inhalation of NO, either in combination with a RM, or separately, were evaluated on patients with ARDS for their enhancing action. 23 patients with ARDS were enrolled, and divided into three groups. The patients in group 1 (n=11) were treated with 5 ppm NO via inhalation, followed by a RM, applying a sustained inflation pressure of 30 - 35 cmH2O for 30 seconds. Group 2 (n=6) received a RM alone, while group 3 (n=3) was treated with NO inhalation alone. The oxygenation and hemodynamic parameters were obtained prior to, and 2, 12, and 24 h after, the respective treatment procedures. For group 1, the PaO2/FiO2 increased from its initial value of 171.8 +/- 67.8 to 203.2 +/- 90.0 2 h after NO inhalation. Further improvement was noted with the continual application of the RM reaching, 215.5 +/- 74.6 (p=0.05) and 254.2 +/- 109.5 (p < 0.05), after 12 and 24 h, respectively. Initially 7 of the subjects did not respond to NO inhalation, but 3 of these non-responders changed into responders 12 h after the RM. The changes in the PaO2/FiO2 from baseline at each time period were greater in group 1 than in the other groups, but with no statistical significance. The hemodynamics of the patients was not significantly altered during the entire study period. We conclude that the combined application of NO inhalation and a RM could be beneficial and safe for patients with ARDS, showing an enhancing effect in improvement of oxygenation. 相似文献
50.
Barabas AZ Cole CD Barabas AD Cowan JM Yoon CS Waisman DM Lafreniere R 《International journal of experimental pathology》2004,85(4):201-212
Summary Diffuse distribution of small, faintly staining, beaded deposits of rat immunoglobulin M (IgM) around the glomerular capillary blood vessels, and a more intensely staining larger deposition in the mesangium, were observed on the kidney sections of normal rats. As glomerular-fixed nephritogenic antigens are known to be present on the epithelial aspect of the glomerular basement membrane (GBM), especially at the soles of foot processes and at the slit pores, it was assumed that the IgM antibodies were directed against these antigens. Investigation by immunofluorescent antibody double-staining techniques of rat kidney sections obtained from normal and rabbit anti-FX1A-injected rats stained for the nephritogenic antigen showed that a number of antigenic sites in the glomeruli and in the mesangium shared antibody hits by heterologous rabbit IgG and autologous rat IgM antibodies. Most sites in the glomeruli stained specifically for rat IgM or rabbit IgG, but preferentially for the latter. The intensely fluorescent mesangial deposits stained mainly for rat IgM, indicating that at these sites the antigenic material was virtually saturated, while areas at the entry to the mesangial space also stained for rabbit IgG, indicating that at these locations free nephritogenic epitopes were still available for reaction with the anti-FX1A antibody. Western blot analysis have shown that the rabbit anti-rat FX1A IgG and the rat anti-rat KF3 IgM antibodies are directed against the same renal tubular-derived antigen with a molecular weight of 70,000. These experimental findings collectively demonstrate that the heterologous IgG and autologous IgM antibodies are directed against the same nephritogenic antigen, which is found in the glomeruli, the mesangium and the proximal convoluted tubules. Thus, the IgM autoantibody has a possible physiological role but, in addition, there is evidence of active immunophagocytic events, manifested in a rapid and continuous entrapment and expulsion of macromolecules after their processing by the mesangial cells of normal and passive Heymann nephritis rats. 相似文献