全文获取类型
收费全文 | 3671556篇 |
免费 | 259558篇 |
国内免费 | 9568篇 |
专业分类
耳鼻咽喉 | 49358篇 |
儿科学 | 121388篇 |
妇产科学 | 100479篇 |
基础医学 | 516507篇 |
口腔科学 | 103816篇 |
临床医学 | 336215篇 |
内科学 | 715351篇 |
皮肤病学 | 86102篇 |
神经病学 | 298055篇 |
特种医学 | 139370篇 |
外国民族医学 | 949篇 |
外科学 | 546728篇 |
综合类 | 78049篇 |
现状与发展 | 9篇 |
一般理论 | 1452篇 |
预防医学 | 284070篇 |
眼科学 | 84954篇 |
药学 | 267464篇 |
12篇 | |
中国医学 | 8102篇 |
肿瘤学 | 202252篇 |
出版年
2021年 | 28788篇 |
2019年 | 29523篇 |
2018年 | 41869篇 |
2017年 | 32013篇 |
2016年 | 36399篇 |
2015年 | 41183篇 |
2014年 | 57104篇 |
2013年 | 85036篇 |
2012年 | 115040篇 |
2011年 | 121590篇 |
2010年 | 72739篇 |
2009年 | 69089篇 |
2008年 | 113046篇 |
2007年 | 120222篇 |
2006年 | 121805篇 |
2005年 | 116741篇 |
2004年 | 112059篇 |
2003年 | 107709篇 |
2002年 | 103874篇 |
2001年 | 177243篇 |
2000年 | 181378篇 |
1999年 | 152678篇 |
1998年 | 43653篇 |
1997年 | 38413篇 |
1996年 | 38563篇 |
1995年 | 37321篇 |
1994年 | 34078篇 |
1993年 | 31964篇 |
1992年 | 118231篇 |
1991年 | 113989篇 |
1990年 | 110268篇 |
1989年 | 106571篇 |
1988年 | 97504篇 |
1987年 | 95426篇 |
1986年 | 89620篇 |
1985年 | 85572篇 |
1984年 | 63780篇 |
1983年 | 54151篇 |
1982年 | 31716篇 |
1979年 | 56389篇 |
1978年 | 39562篇 |
1977年 | 33654篇 |
1976年 | 31350篇 |
1975年 | 33175篇 |
1974年 | 39584篇 |
1973年 | 37840篇 |
1972年 | 35321篇 |
1971年 | 32804篇 |
1970年 | 30296篇 |
1969年 | 28963篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
J M Hurpe C Zerr P Lebreton G Fauchon M Nivaud P Renouf A Khayat J Quesnel 《Annales fran?aises d'anesthèsie et de rèanimation》1987,6(1):11-16
The use of autologous blood transfusion in cardiac surgery is still controversial. This study was prospectively designed to evaluate the haemodynamic and haematological benefits of this method, with special attention to its impact on reducing bank blood requirements. Between November 1983 and October 1984, 160 patients underwent cardiac surgery with extracorporeal circulation and were randomly assigned to two groups: group I (81 patients) was the control group and group II (79 patients) received autologous transfusion following extracorporeal circulation. Blood was withdrawn immediately after the induction of anaesthesia via a jugular catheter and stored in CPD solution at room temperature. The volume of blood removed was replaced with gelatin solutions; after bypass, blood was returned to the patient. There was no difference in systolic, diastolic or mean blood pressures between the two groups. Right atrial pressure and heart rate were not statistically different in both groups. Myocardial perfusion and myocardial oxygen consumption remained unchanged in group II compared with group I. Complete haematological evaluation was carried out before and during bypass, and thereafter daily for the first twelve days of the postoperative period. There was no significative difference between the two groups in platelet counts, fibrinogen levels, prothrombin and partial thromboplastin times. During extracorporeal circulation, mean haematocrit was 22.9 +/- 0.4% in group II and 25.3 +/- 0.5% in group I (p less than 10(-3)). The mean haematocrit time course was similar in both groups during the postoperative period and returned to preoperative value at discharge.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
962.
963.
964.
J. K. M. Quartey 《World journal of urology》1987,5(1):37-40
Summary Short traumatic strictures of the membranous urethra can be repaired by excision and end-to-end urethroprostatic anastomosis. Long membranous or bulbomembranous strictures with or without associated periurethral fibrosis, abscess or urinary fistulae require substitution urethroplasty. Tubed full-thickness skin grafts have a poor chance of survival in such circumstances. Scrotal flaps are hairy, but the penile/preputial island flap, which is relatively hairless, is ideal for such reconstructions in one stage. Difficult perineal exposure led to the development of the transpubic and the abdominoperineal routes. Modification of the incision for perineal prostatectomy by dividing the posterior part of the urogenital diaphragm in the midline up to the urethra improves the exposure so that almost all such reconstructions can be done by the perineal route. A total of 21 cases are reviewed. Flap survival is 100%, but stenosis or restricture at the anastomotic sites can occur as a result of faulty technique. These can be treated by internal urethrotomy or excision and reanastomosis. 相似文献
965.
966.
There is evidence suggesting that the diabetic state adversely affects replication of certain cell populations. We document that exposure to high ambient glucose (20 mM) induces delay in various phases of the cell cycle of human endothelial cells in primary culture. Cells in S phase were labeled with bromodeoxyuridine (an analogue of thymidine), and the cell-cycle position of the labeled cohort was analyzed by flow cytometry at successive time points. The movement of cells exposed to high glucose for 7-8 days was retarded both in S and G2 phases so that the increase in bromodeoxyuridine-positive cells over 24 h was 1.6-fold, versus 2.0-fold in control cultures. In experiments in which mitotic arrest with vinblastine was used to investigate the movement of cells out of G1 phase without interference from reentering cells, depletion of the G1 compartment was significantly inhibited in cultures grown in high glucose. The effects of chronic high glucose on cell cycle occurred while total protein synthesis was not diminished. Acute exposure to high glucose had no effect on cell-cycle traversal or cell generation time. Cell-cycle abnormalities observed in this study may relate to the DNA damage we have previously observed in endothelial cells exposed to high glucose and, if occurring in vivo, could be of pathogenetic importance for the vascular lesions and teratogenicity of diabetes. 相似文献
967.
Failure of genetically selected miniature swine to model NIDDM 总被引:2,自引:0,他引:2
Ten young adult miniature swine from a line reported to be genetically selected for glucose intolerance and eight normal controls were obtained from Colorado State University. They were consecutively exposed to 4 mo of a high-fiber, low-fat standard swine diet; 4 mo of a high-sucrose, high-fat, low-fiber diabetogenic diet; and 4 mo of excess diabetogenic diet for obesification. Results of oral glucose tolerance and intravenous insulin tolerance tests conducted at the end of each regimen were compared. Hyperglycemia was not observed in any animals after any manipulation. Insulin sensitivity was also not influenced by diet. We conclude that F7 low-K miniature swine from this colony fail to model human non-insulin-dependent diabetes. 相似文献
968.
Do frail, disabled, poor, and very old Medicare beneficiaries have higher hospital charges? 总被引:2,自引:0,他引:2
To determine whether basing payments on diagnosis related groups (DRGs) results in mispayment for certain classes of patients, we examined the relation between total Medicare charges per hospitalization and eight beneficiary characteristics (including admission from a nursing home, extreme age, Medicaid enrollment, and disability). We controlled for the hospital in which care was given and the DRG to which the discharge was assigned. The largest effects were that average charges were 6.7% higher for beneficiaries who were disabled before the age of 65 years, and 6.2% higher for patients admitted from a nursing home; charges were 1.5% lower for Medicare beneficiaries who were also enrolled in Medicaid, 3.8% higher for those older than 80 years, and 1.3% lower for those older than 85 years compared with those aged from 80 to 84 years. Because these differences are very small compared with the average variation within DRGs, we conclude that using these beneficiary characteristics in the DRG classification system would only slightly improve DRGs. Medicare's DRG-based payments seem to be substantially equitable with regard to these beneficiary characteristics. 相似文献
969.
Studies were carried out on the penetration of cefuzonam (L-105, CZON), a new synthetic cephalosporin antibiotic, into cerebrospinal fluid, and on the clinical efficacy against bacterial infections. The results are summarized as follows: Concentrations of CZON in cerebrospinal fluid at 1 hour after intravenous administration of 100 mg/kg in cases of furunculosis of the external canal, encephalitis and mumps meningitis were 0.56 micrograms/ml, 1.44 micrograms/ml and 0.33 micrograms/ml, respectively. Concentrations of CZON in cerebrospinal fluid at 1 hour after intravenous administration of 100 mg/kg in 3 cases of purulent meningitis were 2.80-6.40 micrograms/ml at the acute stage and 0.56-1.45 micrograms/ml even at the recovering stage. Sensitivities of clinically isolated strains to CZON were determined and expressed as MIC. MICs of CZON on Haemophilus influenzae, Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae were similar to MIC's of cefmenoxime (CMX), and lower than those of cefoperazone (CPZ), cefmetazole (CMZ), cefatiam (CTM) and Cefazolin (CEZ). The MIC of CZON on Staphylococcus aureus was similar to those of CEZ, CMZ and CTM, and lower than those of CMX and CPZ. Clinical responses of CZON were good in 2 cases of purulent meningitis, good in 2 cases of pyothorax, excellent in 1 case of septicemia, excellent in 3 cases of urinary tract infections, excellent in 7 cases and good in 3 cases out of 10 cases of pneumonia. Clinical responses of other diseases were excellent in 4 cases of bronchitis, good in 1 case of furunculosis of the external canal, excellent in 1 case of tonsillitis. No side effects nor abnormal laboratory findings were observed except 2 cases of mild diarrhea out of 24 cases. 相似文献
970.
During the time period 1958-1967 190 cases of male breast cancer were reported to the Swedish Cancer Registry. The reported cases were thoroughly re-evaluated from the evidence of the clinical records and histopathologic specimens. The material contained 166 cases of histologically verified invasive breast carcinoma which were analyzed with respect to different clinical and histopathologic parameters. In contrast to the rate in females, the breast cancer incidence rate in males did not increase significantly during the period under review, and the age-specific incidence rate did not show a Clemmesen's hook but increased relatively more rapidly at high ages than for female breast carcinoma. The mean age at diagnosis was 4 to 5 years higher in male breast cancer patients than in females. Larger tumours were more frequent among older patients and there was a 5-year shift between the age-distribution curves for small (less than 2 cm) and larger (2-5 cm) tumours. A similar difference was found between pN0 and pN1 tumours. This difference might reflect the progression rate of male breast cancer. The histopathology pattern and distribution of histologic malignancy grades were similar to those in female breast carcinoma with the exception that lobular carcinoma and medullary carcinoma with lymphoid infiltration were lacking in the male material. 相似文献