首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1891篇
  免费   204篇
  国内免费   11篇
耳鼻咽喉   29篇
儿科学   131篇
妇产科学   47篇
基础医学   182篇
口腔科学   85篇
临床医学   222篇
内科学   477篇
皮肤病学   17篇
神经病学   95篇
特种医学   183篇
外科学   278篇
综合类   37篇
预防医学   138篇
眼科学   12篇
药学   72篇
中国医学   6篇
肿瘤学   95篇
  2023年   3篇
  2022年   27篇
  2021年   40篇
  2020年   31篇
  2019年   33篇
  2018年   78篇
  2017年   66篇
  2016年   55篇
  2015年   69篇
  2014年   75篇
  2013年   90篇
  2012年   104篇
  2011年   93篇
  2010年   104篇
  2009年   92篇
  2008年   82篇
  2007年   98篇
  2006年   73篇
  2005年   69篇
  2004年   64篇
  2003年   49篇
  2002年   34篇
  2001年   41篇
  2000年   36篇
  1999年   23篇
  1998年   65篇
  1997年   55篇
  1996年   57篇
  1995年   55篇
  1994年   28篇
  1993年   41篇
  1992年   22篇
  1991年   25篇
  1990年   27篇
  1989年   21篇
  1988年   26篇
  1987年   25篇
  1986年   17篇
  1985年   11篇
  1984年   14篇
  1983年   17篇
  1982年   4篇
  1981年   16篇
  1980年   8篇
  1978年   4篇
  1977年   10篇
  1976年   9篇
  1975年   3篇
  1971年   3篇
  1967年   3篇
排序方式: 共有2106条查询结果,搜索用时 15 毫秒
91.
To evaluate the effect of topography in nanoscale, titanium surfaces were bombarded by argon ions (a chemically inert gas), in an atmosphere of plasma. The effects of surface parameters on morphology, adhesion, proliferation, and MC3T3‐E1 preosteoblasts differentiation were analyzed. Nontreated (smooth) surfaces were used as a control. The levels of average roughness (Ra) observed in bombarded and smooth titanium surfaces were of 95 and 14 nm, respectively. The wettability increased on treated surfaces. The number of attached cells (30 and 60 min) was significantly higher on the bombarded surface. The cell proliferation after 3 and 7 days was also significantly higher on the ion‐bombarded surface. In addition, the ALP activity and expression of osteocalcin were higher in cells grown on the treated surface. The results showed that bombardment with argon ions increased the roughness and the wettability of the Ti surface, promoting a significant increase in the adhesion, proliferation, and differentiation of preosteoblasts.  相似文献   
92.
A phase I clinical trial was initiated to treat patients with stage IV B-derived chronic lymphocytic leukemia (CLL) with the IgG2a murine monoclonal antibody T101. This antibody binds to a 65,000-mol wt (T65) antigen found on normal T lymphocytes, malignant T lymphocytes, and B- derived CLL cells. All of the patients had a histologically confirmed diagnosis of advanced B-derived CLL and were refractory to standard therapy, and more than 50% of their leukemia cells reacted with the T101 antibody in vitro. The patients received T101 antibody two times per week, over two to 50 hours by intravenous administration in 100 mL of normal saline containing 5% human albumin. Twelve patients were treated with a fixed dosage of 1, 10, 50, or 100 mg, and one patient was treated with 140 mg of antibody. It was demonstrated that patients given two-hour infusions of 50 mg developed pulmonary toxicity, with shortness of breath and chest tightness. This toxicity was eliminated when infusions of 50 or 100 mg of T101 were prolonged to 50 hours. All dose levels caused a rapid but transient decrease in circulating leukemia cell counts. In vivo binding to circulating and bone marrow leukemia cells was demonstrated at all dose levels with increased binding at higher dosages. Antimurine antibody responses were not demonstrated in any patients at any time during treatment. Circulating free murine antibody was demonstrated in the serum of only the two patients treated with 100 mg of antibody as a 50-hour infusion and the patient treated with 140 mg of antibody over 30 hours. Antigenic modulation was demonstrated in patients treated at all dose levels but was particularly apparent in patients treated with prolonged infusions of 50 and 100 mg of antibody. We were also able to demonstrate antigenic modulation in lymph node cells, which strongly suggests in vivo labeling of these cells. Overall, T101 antibody alone appears to have a very limited therapeutic value for patients with CLL. The observations of in vivo labeling of tumor cells, antigenic modulation, antibody pharmacokinetics, toxicity, and antimurine antibody formation may be used in the future for more effective therapy when drugs or toxins are conjugated to the antibody.  相似文献   
93.
Kao  KJ; Pizzo  SV; McKee  PA 《Blood》1981,57(3):579-585
A sensitive and precise radioreceptor assay for determining plasma levels of human factor VIII/von Willebrand's factor (FVIII/vWF) has been developed by taking advantage of the FVIII/vWF receptor sites on human platelets. Paraformaldehyde-fixed platelets, which were processed and then stored, retained FVIII/vWF binding activity and therefore could be used as a convenient source of receptors. The human plasma samples to be tested were initially filtered on 4% agarose columns to concentrate the FVIII/vWF protein in the void volume and to remove the factor(s) that interferes with the assay. The percent recovery of FVIII/vWF in the pooled eluent was measured by the recovery of added trace 125I-FVIII/vWF. The coefficients of intra- and interassay variation were 6% and 10%, respectively. The plasma FVIII/vWF concentrations determined by the assay for pooled normal plasma, hemophilia A plasma, and plasmas from two patients with von Willebrand's disease were 16.3 +/- 0.5, 52.6 +/- 1.5, 6.8 +/- 0.8, and 3.2 +/- 0.2 microgram/ml, respectively. The range of plasma FVIII/vWF concentrations varied between 8.3 microgram/ml and 24.9 microgram/ml for 10 normal adults. The plasma FVIII/vWF concentrations determined by the radioreceptor assay correlated well with levels measured by the ristocetin-induced platelet aggregation method, thus demonstrating the functional relevancy of the radioreceptor assay for plasma FVIII/vWF.  相似文献   
94.
The color complementation assay (CCA) is a method of allele-specific DNA amplification by which competitive priming and extension of fluorescently labeled oligonucleotide primers determine the color of DNA amplification product. This diagnostic method precludes the need for radioisotopes, electrophoresis, and multiple high-stringency reaction conditions. The multiplicity of mutant globin genes present in Southeast Asians complicates clinical diagnosis and underscores the importance of DNA-based diagnostic methods. We have applied CCA to distinguish beta A and beta E alleles. Competing 15mer primers were a fluorescein-labeled complement to beta A and a rhodamine-labeled complement to beta E, identical except for their central nucleotides. A common unlabeled primer was used to amplify DNA product, the color of which was determined by the perfectly complementary primer. Color photography and spectrofluorometry, as well as a method of black-white photography that we developed to distinguish fluorescein- and rhodamine- labeled DNA, were used to record results. We applied CCA to define the complex genotype of a Thai woman with thalassemia intermedia, 96% HbE, and 4% HbF whose possible genotypes included several permutations of alpha-thalassemia, beta-thalassemia, and beta E genes. zeta-Globin gene mapping of DNA doubly digested with Bg/II and Asp 718 showed the -alpha 3.7/--SEA genotype, and CCA confirmed homozygous beta E/beta E. The CCA is useful for diagnosing the compound hemoglobin genotypes of Southeast Asians and could be applied also to prenatal diagnosis in this population.  相似文献   
95.
IntroductionFemale sexual dysfunction (FSD) in peripheral polyneuropathies besides diabetes mellitus is still a poorly studied subject. Little is known about sexual function in women with amyloidosis, Guillain–Barré syndrome, or porphyria. Even for the world's most common peripheral polyneuropathies such as diabetes mellitus, knowledge and consensus are still lacking. Familial amyloidotic polyneuropathy (FAP) is the most common cause of genetic systemic amyloidosis, with neurological clinical manifestations similar to diabetes mellitus. Until today, no study on the sexual function of these young female patients has been published.AimTo evaluate FSD in female FAP patients and to compare the results with those of healthy, non‐FAP females.MethodsA questionnaire‐based, observational study comprising 94 nonmenopausal women with a sexual partner (51 FAP and 43 non‐FAP as the control group) was conducted. The Female Sexual Function Index (FSFI)—Portuguese‐validated version was used to assess FSD.Main Outcome MeasuresTotal and subscales scores of the FSFI.ResultsFSD was reported by 42% (95% confidence intervals [CI] 28.3–55.7) of FAP patients compared to 12% of healthy controls. Of all the FAP patients, 39.2% reported problems with desire (95% CI 25.6–52.4), 72.5% reported problems with arousal (95% CI 60.2–84.8), 68% reported lubrication problems (95% CI 55.1–80.9), 62% reported orgasm problems (95% CI 48.5–75.5), 39.2% experienced pain (95% CI, 25.8–52.6), and 49% experienced sexual dissatisfaction (95% CI, 35.3–62.7).Even after multiple logistic regression analysis, FAP is associated with sexual dysfunction in women (OR 4.3, 95% CI 1.2–15.5, P < 0.03), and the affected domains are desire (OR 5.1, 95% CI 1.3–19.7, P < 0.02), arousal (OR 4.7, 95% CI 1.5–14.1, P < 0.007), orgasm (OR 5, 95% CI 1.6–16, P < 0.007), and sexual satisfaction (OR 4.8, 95% CI 1.4–16.9, P < 0.02). Only the use of medication with potential for sexual dysfunction was found as a significant predictor of orgasm disorder (OR 4.2, 95% CI 1.1–15.6, P < 0.03), as did age for sexual dissatisfaction (OR 1.1, 95% CI 1.0–1.2, P < 0.04).ConclusionsFAP as a peripheral polyneuropathy results in FSD, presenting a risk factor four times greater and related to disease severity in terms of desire, arousal, and orgasm disorders, as well as sexual dissatisfaction. Oliveira‐e‐Silva T, Campos Pinheiro L, Rocha Mendes J, Barroso E, and Monteiro Pereira N. Peripheral polyneuropathy and female sexual dysfunction—Familial amyloidotic polyneuropathy as an example besides diabetes mellitus. J Sex Med 2013;10:430-438.  相似文献   
96.
Magnetic resonance (MR) imaging with a whole-body imager was performed in 10 fresh, unfixed whole human brains selected randomly from cadavers. All subjects were neurologically intact before death. T2 time constants were measured within the caudate nucleus, putamen, globus pallidus, cortical gray matter, subcortical white matter, and optic radiation. These regions were then excised, and T2 values were measured again with a 1.5-T MR spectrometer. Quantitative assays of iron, ferritin, and protein from these areas were then performed. Iron concentration varied significantly among brain regions, whereas ferritin and protein concentrations were constant among brain regions and among individuals. Neither iron nor ferritin concentration showed any consistent correlation with T2 values. Histologic examination of brain micro-sections with iron- and ferritin-specific stains of demonstrated poor correlation with biochemical assays of ferritin and iron concentrations. Results indicate that T2 values correlate poorly with iron and ferritin concentrations found in neurologically intact brains.  相似文献   
97.
目的研究臂丛神经损伤膈神经移位术对青壮年患者早期呼吸功能的影响.方法对16例接受膈神经移位治疗的患者,在术前、术后(10 d)进行肺功能指标的比较,同时定期进行门诊随访,观察呼吸系统自觉症状程度.结果13例术后出现了不同程度的供氧不足症状,16例全部出现一侧膈肌抬高,术后第10天肺活量(VC)、肺活量预计值百分数(VC%)分别比术前减少37.98%和26.88%,两者差异有统计学意义(tvc=11.532、tvc%=0,P<0.01).其它项目如残气量(RV)较术前轻度下降,肺总量(TLC)下降值达到术前肺总量的36.49%,残气量/肺总量比值(RV/TLC%)较术前上升了4.75%,上述各指标的差值均有统计学意义.1 s用力呼气量/用力肺活量比值(FEV1/FVC)和术前比基本无改变,但其差值有统计学意义.膈神经移位右侧(10例)与左侧(6例)术前、术后肺活量比较差异有统计学意义.术后随访8个月~2年,所有患者均无明显呼吸困难和胸闷等症状.结论膈神经移位术后对青壮年患者肺容量有较大的丧失,肺通气功能减弱和小气道阻力增加,但其丧失程度在机体自身代偿耐受范围内,不会导致急剧发生的严重呼吸功能障碍.建议对右侧臂丛神经根性损伤的患者,术前进行严格的肺、心功能检查,避免发生较为严重的并发症.  相似文献   
98.

Background

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC) are frequently used to treat appendiceal carcinomatosis. Some patients require multivisceral resection because of the volume of disease. It is unclear whether extent of CRS impacts survival in appendiceal carcinomatosis.

Methods

We analyzed 282 patients undergoing attempted CRS/HIPEC for appendiceal carcinomatosis. Patients were defined as having undergone Extensive CRS (n = 60) if they had >3 organ resections or >2 anastomoses; a subgroup of Extreme CRS patients (n = 10) had ≥5 organ resections and ≥3 anastomoses. Kaplan–Meier survival curves and multivariate Cox-regression models were used to identify prognostic factors affecting outcomes.

Results

Relative to the comparison group, patients undergoing Extensive CRS had a higher median peritoneal carcinomatosis index, operative duration, blood loss, and length of stay. No difference in completeness of cytoreduction, severe morbidity, or 60-day mortality was evident. Subgroup analysis of 10 patients undergoing extreme CRS likewise revealed no increase in severe morbidity or mortality. Median progression-free (PFS) and overall survival (OS) were 23.5 and 74 months in the comparison group; 18.5 (p = 0.086) and 51 (p = 0.85) months in the Extensive CRS group; and 40 months and not reached in the Extreme CRS subgroup. In a multivariable analysis, extent of CRS was not independently associated with PFS or OS.

Conclusions

Extensive CRS is associated with greater OR time, blood loss, and length of stay, but is not associated with higher morbidity, mortality, or inferior oncologic outcomes in patients with appendiceal carcinomatosis.  相似文献   
99.
100.

Introduction

Genital ambiguity is a very common phenomenon in disorders of sex development (DSD). According to the Chicago Consensus 2006, feminizing genitoplasty, when indicated, should be performed in the most virilized cases (Prader III to V). Advances in the knowledge of genital anatomy in DSD have enabled the development and improvement of various surgical techniques. Mobilization of the urogenital sinus (MUS), first described by Peña, has become incorporated by most surgeons. However, the proximity of the urethral sphincter prompts concern over urinary incontinence, especially for full mobilization of the urogenital sinus.

Objective

To retrospectively evaluate the short-term surgical results of feminizing genitoplasty with total mobilization of the urogenital sinus in patients with DSD.

Methods

Review of medical records of all patients undergoing feminizing genitoplasty with mobilization of the urogenital sinus. We evaluated the rates of complications from surgery and of urinary incontinence, as well as cosmetic results, according to the opinion of the surgeon and the family.

Results

A total of 8 patients were included in the study. The mean age at surgery was 51 months. Congenital adrenal hyperplasia (CAH) was diagnosed in six patients, and gonadal dysgenesis in the other two. The vagina was separated from the urethra, with suitable distance in all cases. No patient had urinary incontinence after surgery. The mean follow-up of patients was.20 months (3–56 months). In all cases, surgeons recorded being satisfied with the aesthetic result of post-surgical genitalia. The family was recorded as satisfied with the aesthetic result of the genitalia after surgery. In every case, there was no need for a second surgical procedure.

Conclusion

The total mobilization of the urogenital sinus is a feasible and safe technique. The technique permits good cosmetic results, and urinary incontinence is absent.

Type of study

Therapeutic study.

Level of evidence

Level III.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号