全文获取类型
收费全文 | 1318篇 |
免费 | 118篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 57篇 |
妇产科学 | 39篇 |
基础医学 | 144篇 |
口腔科学 | 44篇 |
临床医学 | 159篇 |
内科学 | 285篇 |
皮肤病学 | 18篇 |
神经病学 | 110篇 |
特种医学 | 131篇 |
外科学 | 168篇 |
综合类 | 42篇 |
一般理论 | 2篇 |
预防医学 | 59篇 |
眼科学 | 10篇 |
药学 | 72篇 |
肿瘤学 | 107篇 |
出版年
2021年 | 16篇 |
2020年 | 16篇 |
2019年 | 14篇 |
2018年 | 34篇 |
2017年 | 22篇 |
2016年 | 12篇 |
2015年 | 34篇 |
2014年 | 29篇 |
2013年 | 24篇 |
2012年 | 49篇 |
2011年 | 58篇 |
2010年 | 47篇 |
2009年 | 45篇 |
2008年 | 58篇 |
2007年 | 55篇 |
2006年 | 65篇 |
2005年 | 40篇 |
2004年 | 45篇 |
2003年 | 27篇 |
2002年 | 30篇 |
2001年 | 33篇 |
2000年 | 40篇 |
1999年 | 40篇 |
1998年 | 45篇 |
1997年 | 35篇 |
1996年 | 56篇 |
1995年 | 30篇 |
1994年 | 26篇 |
1993年 | 24篇 |
1992年 | 27篇 |
1991年 | 27篇 |
1990年 | 26篇 |
1989年 | 24篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 18篇 |
1985年 | 26篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1973年 | 8篇 |
1972年 | 12篇 |
1971年 | 6篇 |
排序方式: 共有1448条查询结果,搜索用时 0 毫秒
11.
The E6–AP Ubiquitin–Protein Ligase (UBE3A) Gene Is Localized within a Narrowed Angelman Syndrome Critical Region 下载免费PDF全文
12.
This study analyses the influence of female and male patient age and human
menopausal gonadotrophin (HMG) requirements on clinical pregnancy rates and
live birth rates with ovulation stimulation using HMG in combination with
intrauterine insemination (IUI). In this study, 363 consecutive HMG/IUI
treatment cycles in 184 patients carried out at a university fertility
centre were analysed in a retrospective fashion. The main outcomes measured
were clinical pregnancy rates and live birth rates. Increased female
partner age (> or = 35) and male partner age (> or = 40) were found
to negatively influence pregnancy rates with HMG/ IUI therapy. In addition,
this study demonstrated a critical threshold of HMG requirements beyond
which pregnancy did not occur. No pregnancies occurred in treatment cycles
requiring > 25 ampoules (1875 IU) of menotrophins to achieve follicular
maturity, irrespective of patient age. In conclusion, female partner age,
male partner age, and HMG requirements all significantly influence
pregnancy rates with HMG/IUI therapy.
相似文献
13.
Background
Ischemic stroke is the most common cause of disability in North America and in addition to the generally accepted risk factors, there is increasing evidence for the potential pathophysiological role of genes. One of these genes, the endothelial nitric oxide synthase gene (NOS3) has been reported as a genetic risk factor for ischemic stroke. To independently confirm and extend the results of these previous reports, we investigated this gene as a risk factor for stroke in an ethnically diverse study population. 相似文献14.
Sutcliffe MJ Mueller OT Kousseff BG Dumont DP McFarland JA Mawani F Conforto D Ranells JD 《American journal of medical genetics》2001,102(2):192-199
We report on a 3.5-year-old girl with a mosaic karyotype including full trisomy 18, normal cells and a majority of cells with partial trisomy involving an extra chromosome 18 deleted at band q22. She had cardiac and CNS anomalies, dysmorphic facial features failure to thrive and developmental delay. A gastrostomy tube was placed at 2 years of age. The combination of improved nutrition and optimal developmental therapy has led to her sitting supported, attempting to stand and enhancement of her cognitive and non-verbal communication abilities. Molecular investigation of the patient and her parents using microsatellite analysis has led to the conclusion that, as expected, the additional copy of chromosome 18 constituting the full trisomic cell line is maternal meiosis I in origin. The data, however, indicate that in the trisomic cell line containing the deleted chromosome 18q, the structurally abnormal 18 was of paternal origin. We think this case is the first described with both structural and numerical trisomic mosaicism involving chromosome 18 in a liveborn infant. We propose a mechanism of origin and review the literature, comparing the clinical presentation of this case with individuals having full or partial trisomy 18. 相似文献
15.
Immune responsiveness against the human placenta. I. Generation of cellular and humoral activity in experimental animals. 总被引:2,自引:1,他引:2 下载免费PDF全文
Using a new adaptation of the 51Cr release assay, it was found that plasma membrane vesicles from the human placental microvillous surface were not only capable of eliciting both cellular and humoral immunity in mice, but were also susceptible to lysis by these immune components. The production of cytotoxic cells and circulating antibody in immunized animals was only observed in the presence of Freund's complete adjuvant. The cells exhibited reactivity only against vesicles from a limited range of placentae, while the antibodies showed reactions against vesicles from a wider range of placentae. These vesicles were also susceptible to lysis by antisera raised against placental alkaline phosphatase but were resistant to attack by antibodies raised against normal human serum and HLA (multispecific) determinants and by a cytotoxic monoclonal antibody against human beta 2-microglobulin. The cellular cytotoxicity in the spleens of immunized animals could be abrogated if the cells were pretreated with AKR anti-C3H antiserum and complement. Further, in the spleens of in immunized animals, a population of cells was detected that exhibited a 'natural' cytotoxicity against several of the membrane preparations. This cytotoxicity was heat-labile, being abrogated if the cells were preincubated at 37 degrees for 4 hr before the assay, but was resistant to attack by the anti-Thy 1 antiserum. The results indicate that the use of 51Cr-labelled placental microvillous vesicles is a useful way of searching for anti-trophoblast immunity which may now be applied to the search for immune responses in pregnancy. 相似文献
16.
Kovalikova Z; Hoehn-Berlage MH; Gersonde K; Porschen R; Mittermayer C; Franke RP 《Radiology》1987,164(2):543-548
The T1 and T2 values of adenocarcinoma EO 771 inoculated into the hind leg of mice are characterized and correlated with the histopathologic state of the tumor. Growth-dependent changes (indicated by a T1 of 630-910 msec and a T2 of 68-185 msec) can be separated into four characteristic phases. The increase in relaxation times in the early phases (A and B) is due to an increasing amount of viable tumor tissue relative to normal muscle tissue. In the later phases (C and D), a decline of the relaxation parameters is observed that is parallel to an increase in the fraction of necrotic tissue. By multiexponential analysis, two relaxation components (indicated by and, respectively) for T1 and T2 and the corresponding fractions alpha 1 and alpha 2 can be observed for both tumor and surrounding muscle tissue. A tissue criterion ("magnetic resonance fingerprint") is defined by a combination of these multiple parameters. This criterion allows separation of not only muscle and tumor tissue but also viable (early state) and necrotic (late state) tumor tissue. 相似文献
17.
Osteosarcomatosis 总被引:10,自引:0,他引:10
Hopper KD; Moser RP Jr; Haseman DB; Sweet DE; Madewell JE; Kransdorf MJ 《Radiology》1990,175(1):233-239
A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized. 相似文献
18.
RAJVIR BHALWAR HS SANDHU RC AHUJA GK SINGH RP MISRA 《Medical Journal Armed Forces India》1994,50(3):175-180
A population based hybrid design combining element of cohort and cross-sectional approach was used to develop a simple clinical algorithm to predict individual probability of developing hypertension (systolic BP > 140 mm Hg and/or diastolic BP > 90 mmHg). 3615 soldiers initially normotensive at the time of induction into high altitude, were studied by systematic random sampling. Multiple logistic regression analysis showed a high significant association between hypertension and age, body mass index (BMI), tobacco smoking and alcohol consumption. Using the constant/coefficient values obtained from the logistic model and the receiver operating characteristics (ROC) curve analysis, the following predictive rule was developed – To the age in years, add (BMIx 3.86); also add 5.53 if he is a smoker; and add 19.81 if he consumes alcohol. If the total exceeds 142, the individual is at high risk of developing hypertension. This algorithm carries a sensitivity of 68.2% and specificity of 78.5%.KEY WORDS: Hypertension, High altitude 相似文献
19.
Analysis of splice variants and site-directed mutants of the AMPA receptor GluR3 expressed in Xenopus oocytes has shown that lithium produces a large potentiation of the GluR3 flop splice variant and suggested that lithium might inhibit rapid desensitization, which is characteristic of this receptor (Karkanias, N. and Papke, R., Subtype-specific effects of lithium on glutamate receptor function. J. Neurophysiol., 81 (1999) 1506-1512). We now show that mutation of the 769R/ G desensitization site (Lomeli, H.M.J., Melcher, T., Hoger, T., Geiger, J.R., Kuner, T., Monyer, H., Higuchi, M.B.A. and Seeburg, P.H, Control of kinetic properties of AMPA receptor channels by nuclear RNA editing. Science, 9(266) (1994) 1709-1713) greatly attenuates the lithium-induced potentiation of GluR3. Additionally, experiments with the non-desensitizing site-directed mutant GluR3(L507Y) (Stern-Bach, Y., Russo, S., Neuman, M. and Rosenmund, C., A point mutation in the glutamate binding site blocks desensitization of AMPA receptors. Neuron, 21 (1998) 907-918) further confirms that lithium enhances GluR3 responses by reducing desensitization, since lithium's effects are reversed in this mutant. Lithium's effects on GluR3 desensitization are distinct from the effects of aniracetam on desensitization. Specifically, aniracetam, which potentiates wild-type AMPA receptors, is ineffective on the non-desensitizing GluR3(L507Y) mutant, but has synergistic effects with lithium on wild-type receptors. 相似文献
20.
The authors describe the technique of Asleep-Awake-Asleep anesthesia for open dorsal rhizotomy in a 78-year-old female patient, admitted to the hospital with intractable pain in the distribution of C2 dermatome following a road traffic accident. The patient was anesthetised and the rhizotomy performed using the intradural approach. Anesthesia was conducted by Total Intravenous Anesthesia using a Target Controlled Infusion system. The patient was awakened twice intraoperatively to verify success of the rhizotomy. Complete pain relief was obtained and maintained at 1 year follow-up. 相似文献