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51.
A study was conducted that analyzed the relationship between various characteristics of the preclinical curriculum and institutional performance on the Part I examination of the National Board of Medical Examiners (NBME) at a sample of 85 U.S. medical schools. Total scheduled hours per week was the single curriculum characteristic having a positive and significant relationship with institutional NBME examination performance. However, when the data were controlled by medical school selectivity in admissions and institutional policy on the taking of the examination, total scheduled hours per week failed to make a significant contribution to the prediction of performance. The results were viewed as failing to provide support and justification for intense preclinical curriculum loads on the basis that this would enhance NBME examination performance. The authors conclude that simple comparisons of schools on the basis of mean NBME examination performance are meaningless unless the entering abilities of students and school policies on the examination are taken into account. The authors also suggest that those schools that prescribe heavy and intense preclinical curriculum loads should reexamine those policies in light of recommendations of the Project Panel on the General Professional Education of the Physician and College Preparation for Medicine.  相似文献   
52.
To study the relationship between development of lung function and bronchial responsiveness, we examined 106 subjects recruited from a random sample of 527 subjects, aged 8-18 years, from Copenhagen. Lung function and bronchial responsiveness to inhaled histamine were measured at two occasions, in 1986 and 1988. The participating subjects (n = 106) were divided into three groups: (a) 20 asthmatics with bronchial hyperresponsiveness (BHR), (b) 42 nonasthmatic subjects with BHR in 1986, and (c) 44 controls without BHR. In 1986, FEV1 expressed as percentage of predicted value, was found to be similar in the three groups (91%, 94%, and 99%, respectively). The increase in height during the observation period was found to be 5, 6, and 6 cm, respectively, in the three groups. However, at the second examination, in 1988, FEV1 was found to be significantly reduced in both asthmatics (87%) and nonasthmatic subjects (85%) compared with the controls (103%). In 1988, 16 asthmatics (80%) and 24 (57%) nonasthmatic subjects were found to have BHR, whereas none of the controls were found to have BHR. A multiple regression analysis was used to determine the correlation between change in FEV1 and potential factors of importance. The change in FEV1 was highly correlated with the presence of BHR in 1986, however, no correlation was found between change in FEV1 and change in bronchial responsiveness. In conclusion, nonasthmatic subjects with former BHR showed signs of airflow obstruction and less increase in lung function during growth irrespective of the change in level of bronchial responsiveness, which may suggest a risk for subsequent development of obstructive lung disease.  相似文献   
53.
S Brett  J M Orrell  J Swanson Beck    J Ivanyi 《Immunology》1992,76(1):129-132
Mice infected by intraperitoneal injection of Mycobacterium tuberculosis were studied over a 23-week period. They showed progressive infection in the lung (with increasing microbial count and granuloma size) whereas viable bacillary counts remained largely stationary in the spleen and in the liver. The influence of H-2 genes on the progression of the lung infection was studied in four congenic strains of animals with B10 and three congenic strains of animals with BALB backgrounds. H-2k mice had significantly higher bacterial counts in the lung than H-2b mice on both B10 and BALB backgrounds, BALB. K (H-2k) mice were also more susceptible than BALB/c (H-2d) mice. Results with recombinant strains showed that bacillary counts and granulomatous infiltration were lower in the B10 (KbAbE-Db) compared with B10.A(3R) (KbAbEbDd) strain and in B10.A(4R) (KkAkE-Db) compared with B10.BR (KkAkEkDk) mice. This resistance to the late expansion of tuberculous infection in the lungs may be associated with the lack of an expressed I-E molecular or with the expression of the Db molecule.  相似文献   
54.
The objective of this study was to determine the frequency and significance of the MR findings of incomplete shell collapse for detecting implant rupture in a series of surgically removed breast prostheses. MR images of 86 breast implants in 44 patients were studied retrospectively and correlated with surgical findings at explanation. MR findings included (a) complete shell collapse (linguine sign), 21 implants; (b) incomplete shell collapse (subcapsular line sign, teardrop sign, and keyhole sign), 33 implants; (c) radial folds, 31 implants; and (d) normal, 1 implant. The subcapsular line sign was seen in 26 implants, the teardrop sign was seen in 27 implants, and the keyhole sign was seen in 23 implants. At surgery, 48 implants were found to be ruptured and 38 were intact. The MR findings of ruptured implants showed signs of incomplete collapse in 52% (n = 25), linguine sign in 44% (n = 21), and radial folds in 4% (n = 2). The linguine sign perfectly predicted implant rupture, but sensitivity was low. Findings of incomplete shell collapse improved sensitivity and negative predictive values, and the subcapsular line sign produced a significant incremental increase in predictive ability. MRI signs of incomplete shell collapse were more common than the linguine sign in ruptured implants and are significant contributors to the high sensitivity and negative predictive values of MRI for evaluating implant integrity.  相似文献   
55.
Background. The optimal management of patients with renal cell carcinoma with inferior vena cava tumor thrombus remains unresolved. Traditional approaches have included resection with or without the use of cardiopulmonary bypass. Chemotherapy has played a minor role except for biotherapeutic agents used for metastatic disease.

Methods. From January 1989 to January 1996, 37 patients with renal cell carcinoma and inferior vena cava tumor thrombus underwent surgical resection. The 27 men and 10 women had a median age of 57 years (range, 29 to 78 years). Thirty-six patients presented with symptoms; 21 had hematuria. Distant metastases were present in 12 patients. Tumor thrombi extended to the infrahepatic inferior vena cava (n = 16), the intrahepatic inferior vena cava (n = 16), the suprahepatic inferior vena cava (n = 3), and into the right atrium (n = 2). All tumors were resected by inferior vena cava isolation and, when necessary, extended hepatic mobilization and Pringle maneuver, with primary or patch closure of the vena cavotomy. Cardiopulmonary bypass was necessary in only 2 patients with intraatrial thrombus.

Results. Complications occurred in 11 patients, and 1 patient died 2 days postoperatively of a myocardial infarction (mortality, 2.7%). Twenty patients are alive; overall 2- and 5-year survival rates were 61.7% and 33.6%, respectively. For patients without lymph node or distant metastases (stage IIIa), 2- and 5-year survival rates were 74% and 45%, respectively. The presence of distant metastatic disease (stage IV) at the time of operation did not have a significant adverse effect on survival, as reflected by 2- and 5-year survival rates of 62.5% and 31.3%, respectively. Lymph node metastases (stage IIIc) adversely affected survival as there were no long-term survivors.

Conclusions. Resection of an intracaval tumor thrombus arising from renal cell carcinoma can be performed safely and can result in prolonged survival even in the presence of metastatic disease. In our experience, extracorporeal circulatory support was required only when the tumor thrombus extended into the heart.  相似文献   

56.
White mice, 18-20 g, were fed purified diets containing two weight percent safflower oil plus ten weight percent menhaden, corn, or olive oil for 2 wk. Menhaden oil ingestion resulted in significantly higher levels of 22:6(n-3) and 20:5(n-3), particularly 22:6(n-3), and lower levels of 20:4(n-6) and 18:2(n-6) in cardiac sarcoplasmic reticulum (SR) phospholipids than did corn or olive oil ingestion. These changes in fatty acid composition resulted in a significant decrease in the value of the n-6/n-3 fatty acid ratio of cardiac SR phospholipids. The ratio was 2.8 versus 0.2 in choline phospholipids and 1.9 versus 0.2 in ethanolamine phospholipids in SR of mice fed corn or menhaden oil, respectively. This reduction in the n-6/n-3 fatty acid ratio was associated with a lower relative activity of Ca2+-Mg2+ ATPase, and a lower initial rate of calcium transport and maximum calcium uptake in SR vesicles from mice fed menhaden oil rather than olive or corn oils. The specific activity of NADPH cytochrome C reductase (EC 1.6.2.3) of cardiac SR was not affected by dietary lipids. These data indicate that modification of SR by 22:6(n-3) may change the SR bilayer structure resulting in alteration of the calcium transport properties of SR vesicles. In addition, our results suggest that reduction of calcium flux across cardiac SR following fish oil consumption may also reduce the susceptibility of myocytes to rapid changes in calcium concentrations which may occur during ischemia and reperfusion.  相似文献   
57.
Interferon alpha (IFN-alpha) can be effective therapy for patients with chronic kidney disease who have chronic hepatitis C (HCV). However, acute allograft rejection has been reported in association with IFN-alpha following kidney transplantation, and therefore IFN therapy is recommended prior to, rather than after, kidney transplantation whenever feasible. The special case of repeat allograft recipients who contract HCV after the first transplantation presents special difficulties. This report features the case of a repeat allograft recipient who presented with neutropenic fevers after 5 months of pegylated IFN-alpha therapy, initiated 6 months following the functional loss of his third graft and the reinitiation of hemodialysis (HD). Physical exam, radiographic and laboratory findings led to allograft nephrectomy. The pathologic findings supported a diagnosis of acute-on-chronic rejection. This represents a rare case of IFN-alpha induced rejection following allograft failure and return to HD in a repeat allograft recipient. It also calls attention to the need for a high index of suspicion for the development of allograft rejection, which may require allograft nephrectomy even after allograft 'failure'.  相似文献   
58.
Few bureaucratic appointments have raised as many eyebrows as the announcement that controversial health economist Jane Fulton would become Alberta's deputy minister of health. A staunch supporter of private health care, Fulton joins the Alberta ministry just as Premier Ralph Klein's Progressive Conservatives gear up for a battle with Ottawa over two-tier medicine.  相似文献   
59.
OBJECTIVE: To examine the association between socioeconomic position and coping strategies in musculoskeletal pain. DESIGN AND SUBJECTS: Cross-sectional study of a random sample of 40- and 50-year-old Danes, participation rate 69%, n=7,125. The study included 1,287 persons who reported functional limitations due to musculoskeletal pain. METHODS: Data was collected by postal questionnaires and scales were developed on problem-solving coping and avoidant coping, based on a range of preliminary studies. Multivariate logistic regression analyses was used to study the correlation with socioeconomic position, measured by occupational social class. RESULTS: Among women, there was no correlation between social class and avoidant coping, but a significant decrease in the use of problem-solving coping by decreasing social class, adjusted odds ratio (OR) = 2.64 (95% confidence interval (CI) 1.31-5.32) in social class V vs social classes I + II. Among men, there was no correlation between social class and problem-solving coping, but a significant increase in the use of avoidant coping with decreasing social class, adjusted OR = 3.31 (95% CI 1.75-6.25) in V vs I + II. CONCLUSION: It is important for clinicians who advise and support patients in their response to musculoskeletal pain to be aware of socioeconomic differences in coping strategies. Gender differences in the association between socioeconomic factors and coping should be further investigated.  相似文献   
60.
The T-cell recognition of HLA-DR-peptide complexes is generally restricted by the polymorphism of the DRB molecules but pluriallelic restriction has been described. The molecular basis of restriction and promiscuity of such peptide-specific responses is poorly understood. We isolated a panel of T-cell lines specific for the tetanus toxin peptide p2 (TT830-843) exhibiting pluriallelic restriction by DR11 and DR8 alleles. Fine restriction specificity of the T-cell lines was examined in functional assays against DR oligotyped APCs expressing different variants of DR11 and DR8 alleles. Our results show that (a) polymorphisms between serologically related alleles are relevant in terms of restriction of the peptide-specific T-cell response; in some instances, a single amino acid substitution can determine the restriction of a T-cell line; (b) different patterns of restriction are not the result of specific differences in DR-p2 binding as p2 peptide binds to all DR11 and DR8 alleles tested (DRB1* 1101, -1102, -1103, -1104, 110X, -0801, -0802, -0803, and -0806); and (c) pluriallelic restriction of the peptide-specific T-cell responses correlates with the presence of a DRB1 α-helix motif (67-71-86) shared by some DR11 and DR8 alleles. Possible implications of pluriallelic restriction of peptide-specific T-cell response in autoimmune disorders associated with DR11 and DR8 are discussed.  相似文献   
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