全文获取类型
收费全文 | 4520篇 |
免费 | 487篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 266篇 |
妇产科学 | 159篇 |
基础医学 | 773篇 |
口腔科学 | 82篇 |
临床医学 | 554篇 |
内科学 | 1074篇 |
皮肤病学 | 56篇 |
神经病学 | 218篇 |
特种医学 | 276篇 |
外科学 | 469篇 |
综合类 | 101篇 |
一般理论 | 3篇 |
预防医学 | 424篇 |
眼科学 | 38篇 |
药学 | 283篇 |
中国医学 | 1篇 |
肿瘤学 | 215篇 |
出版年
2021年 | 51篇 |
2018年 | 71篇 |
2017年 | 37篇 |
2015年 | 49篇 |
2014年 | 65篇 |
2013年 | 102篇 |
2012年 | 153篇 |
2011年 | 166篇 |
2010年 | 131篇 |
2009年 | 121篇 |
2008年 | 169篇 |
2007年 | 189篇 |
2006年 | 173篇 |
2005年 | 155篇 |
2004年 | 132篇 |
2003年 | 176篇 |
2002年 | 129篇 |
2001年 | 116篇 |
2000年 | 137篇 |
1999年 | 143篇 |
1998年 | 100篇 |
1997年 | 96篇 |
1996年 | 104篇 |
1995年 | 84篇 |
1994年 | 81篇 |
1993年 | 74篇 |
1992年 | 115篇 |
1991年 | 119篇 |
1990年 | 112篇 |
1989年 | 130篇 |
1988年 | 122篇 |
1987年 | 121篇 |
1986年 | 108篇 |
1985年 | 100篇 |
1984年 | 57篇 |
1983年 | 52篇 |
1982年 | 40篇 |
1981年 | 48篇 |
1980年 | 39篇 |
1979年 | 86篇 |
1978年 | 61篇 |
1977年 | 45篇 |
1976年 | 47篇 |
1975年 | 46篇 |
1974年 | 55篇 |
1973年 | 36篇 |
1972年 | 40篇 |
1971年 | 44篇 |
1970年 | 44篇 |
1967年 | 35篇 |
排序方式: 共有5011条查询结果,搜索用时 15 毫秒
991.
A prospective study of multiple needle biopsies versus a single open biopsy for testicular sperm extraction in men with non-obstructive azoospermia 总被引:13,自引:9,他引:4
Little is known about the efficacy and the factors affecting the outcome of
fine needle aspiration biopsy of the testis for sperm retrieval in
azoospermic men with defective spermatogenesis. A prospective study was
designed to compare the efficacy of needle and open (window) testicular
biopsies for testicular epididymal sperm extraction (TESE) in 35
consecutive men with azoospermia due to defective spermatogenesis
undergoing testicular biopsy for intracytoplasmic injection of oocytes.
Each of the consecutive 35 patients underwent TESE using a 19 gauge
butterfly needle followed by a window (1-1.5 cm-sized incision) testicular
biopsy in the same procedure. The extraction of spermatozoa into culture
medium was compared with the assessment of testicular biopsies by
histology, the mode of biopsy (needle or open biopsy) and the amount of
tissue retrieved by either method. Testicular spermatozoa were retrieved in
22 (63%) who had an open testicular biopsy compared with five (14%)
patients who had multiple needle biopsies, respectively; the difference was
statistically significant. Open testicular biopsy retrieves more testicular
tissue than needle biopsy. Needle testicular biopsy retrieved testicular
spermatozoa in 50% of those with hypospermatogenesis, 10% with focal
spermatogenesis and in no patients with maturation arrest or Sertoli
cell-only pattern. In contrast, sperm retrieval was successful in 100%, 90%
and 66% of those with respective histologies using open testicular biopsy.
Other than bruising, for which they required no analgesia, none of the
patients suffered any obvious complications associated with traditional
testicular biopsy. We conclude that open testicular biopsy is more
effective than needle biopsy for the retrieval of testicular spermatozoa in
azoospermic men with defective spermatogenesis. The difference observed may
be related to the amount of testicular tissue retrieved and to the
influence of testicular histology.
相似文献
992.
Immune complexes were detected by plain and immunoelectron microscopy amongst electron-dense material that rapidly formed and extended over and into the cartilaginous surfaces of immune arthritic rabbits' knees. The sinuous extension of electron-dense material into the surface matrix was associated with fragmentation and detachment, resulting in erosions. The findings implicate the formation of immune complexes in the destructive process of the matrix. Since the eroded pannus-free matrix of rheumatoid cartilage surfaces contains extensive concentrations of immune complexes, the data of this immune arthritis model suggest a causative relation between immune complexes and matrix loss in rheumatoid arthritis. 相似文献
993.
C. M. Fraser A. Fisher M. J. Cooke I. D. Thompson T. W. Stone 《Psychopharmacology》1997,130(4):334-342
The Y-maze was used to assess spontaneous alternation behaviour in mice to examine possible interactions between the N-methyl-D-aspartate receptor channel blocker dizocilpine and purine receptor agonists and antagonists. Scopolamine reduced spontaneous
alternation. Dizocilpine also produced a dose-dependent reduction in alternation scores, which was accompanied by an increase
in locomotion. The selective A1 adenosine receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (CPX) had no effect when administered alone, or in combination
with scopolamine. However, when co-administered with dizocilpine, CPX reversed both the deficit in alternation behaviour and
also the increase in locomotion induced by dizocilpine. The A1 selective agonist N
6-cyclopentyladenosine (CPA) had no effect on either locomotion or alternation scores when administered alone, but in combination
with scopolamine, CPA attenuated the scopolamine-induced deficit. CPA had no significant effect on the dizocilpine-induced
deficit. The A2 selective agonist N
6-[2-(3, 5-dimethoxyphenyl)-2(2-methylphenyl)-ethyl]adenosine (DPMA), had no effect on spontaneous alternation when administered
alone, but did cause a depression of locomotion. DPMA had no significant effect when co-administered with scopolamine, but
reversed the deficit in spontaneous alternation, and the increase in locomotion induced by dizocilpine. The A2 selective antagonist 3,7-dimethyl-1-propargylxanthine (DMPX) had no effect when given alone or in combination with scopolamine,
but when co-administered with dizocilpine, DMPX reversed the reduction in spontaneous alternation caused by dizocilpine. It
is concluded that dizocilpine has a detrimental effect on spontaneous alternation which is mediated partly by A1 and A2 adenosine receptors.
Received: 21 March 1996 / Final version: 6 November 1996 相似文献
994.
M E Gore J C Cooke E Wiltshaw J M Crow D O Cosgrove C A Parsons 《British journal of cancer》1989,60(5):751-754
We have carried out a prospective study on the impact of computed tomography (CT) and ultrasonography (US) on the management of patients with carcinoma of the ovary. Seventy-eight CT and 88 US scans were performed on 94 patients. Clinicians decided patient management prospectively at the time the CT and/or US was ordered. Clinical assessment differed from the result obtained by CT or US in 45% of cases (35/78 and 40/88, respectively). CT and US altered patient management in only a minority of cases (14/78, 18% and 9/88, 10% respectively). Even when the scan and clinical assessments differed, management was only altered on 14/35 (40%) occasions after CT and on 9/40 (23%) occasions after US, a difference which was not significant. In patients with clinically undetectable disease, management was altered by CT on 17% of occasions and by US on 10%. We conclude that in patients with carcinoma of the ovary CT and US alters patient management in a minority of cases. In view of current financial restrictions in health care, clinicians should be more selective in the use of these imaging techniques. Furthermore, we recommend that similar prospective studies are performed for other clinical situations. 相似文献
995.
Geometry of the humeroulnar joint 总被引:4,自引:0,他引:4
R Shiba C Sorbie D W Siu J T Bryant T D Cooke H W Wevers 《Journal of orthopaedic research》1988,6(6):897-906
Clinical results with elbow prostheses have been disappointing. A detailed knowledge of elbow joint geometry and mechanics is necessary to improve prosthetic design. In this study, the humeroulnar articulation of four human cadaver elbows was examined using surface analytic methods. In this article, the location of the transverse axis of elbow flexion-extension is suggested in relation to well-defined landmarks, the medial and lateral epicondyles, and subsequently to the line connecting their most lateral points--the transepicondylar line. The geometry of the structures responsible for the carrying angle is discussed, as is the extent of cartilage-covered bearing areas of the lower humerus and upper ulna. Implications pertaining to prosthetic design and surgical technique resulting from this study are discussed. 相似文献
996.
997.
Familial hemiplegic migraine in the west of Scotland: a clinical and genetic study of seven families. 下载免费PDF全文
M A Ahmed E Reid A Cooke R Arngrímsson J L Tolmie J B Stephenson 《Journal of neurology, neurosurgery, and psychiatry》1996,61(6):616-620
OBJECTIVES: Clinical and genetic characterisation of families in the west of Scotland with familial hemiplegic migraine. METHODS: Families with familial hemiplegic migraine were identified via probands attending the regional paediatric neurology and child development centre. All available family members were assessed clinically and genetic linkage studies for the known familial hemiplegic migraine gene locus on chromosome 19 were carried out on three families. RESULTS: Seven unrelated kindreds with familial hemiplegic migraine were identified. Clinical information was obtained on 138 family members, 27 of whom fulfilled the International Headache Society criteria for familial hemiplegic migraine. Whereas the severity, duration, frequency, and temporal progression of acute hemiplegic migrainous attacks showed pronounced variability within and between families, and even in the same individual over time, no true clinical heterogeneity of the condition was apparent. Genetic linkage analysis gave results consistent with linkage to the familial hemiplegic migraine gene locus on chromosome 19p in one family. In the other two families, evidence against linkage was obtained. There was no significant clinical difference between these three families. CONCLUSIONS: This study provides characterisation of the clinical features of familial hemiplegic migraine in a British population. Significant variability was found in the frequency and character of migraine attacks within and between families, and no true clinical heterogeneity was identified. On the other hand, further evidence for genetic heterogeneity of the condition was found. 相似文献
998.
A John Rush Lauren B Marangell Harold A Sackeim Mark S George Stephen K Brannan Sonia M Davis Robert Howland Mitchel A Kling Barry R Rittberg William J Burke Mark H Rapaport John Zajecka Andrew A Nierenberg Mustafa M Husain David Ginsberg Robert G Cooke 《Neuropsychopharmacology》2005,58(5):347-354
BACKGROUND: Vagus nerve stimulation (VNS) alters both concentrations of neurotransmitters or their metabolites and functional activity of central nervous system regions dysregulated in mood disorders. An open trial has suggested efficacy. METHODS: This 10-week, acute, randomized, controlled, masked trial compared adjunctive VNS with sham treatment in 235 outpatients with nonpsychotic major depressive disorder (n = 210) or nonpsychotic, depressed phase, bipolar disorder (n = 25). In the current episode, participants had not responded adequately to between two and six research-qualified medication trials. A two-week, single-blind recovery period (no stimulation) and then 10 weeks of masked active or sham VNS followed implantation. Medications were kept stable. Primary efficacy outcome among 222 evaluable participants was based on response rates (>/=50% reduction from baseline on the 24-item Hamilton Rating Scale for Depression [HRSD(24)]). RESULTS: At 10-weeks, HRSD(24) response rates were 15.2% for the active (n = 112) and 10.0% for the sham (n = 110) groups (p = .251, last observation carried forward [LOCF]). Response rates with a secondary outcome, the Inventory of Depressive Symptomatology - Self-Report (IDS-SR(30)), were 17.0% (active) and 7.3% (sham) (p = .032, LOCF). VNS was well tolerated; 1% (3/235) left the study because of adverse events. CONCLUSIONS: This study did not yield definitive evidence of short-term efficacy for adjunctive VNS in treatment-resistant depression. 相似文献
999.
The diagnosis by computed tomography of brachial plexus lesions following radiotherapy for carcinoma of the breast 总被引:1,自引:0,他引:1
The region of the brachial plexus in the root of neck and axilla was examined by computed tomography (CT) in 62 patients attending the Royal Marsden Hospital. Forty-two of these patients had been treated by surgery and subsequent radiotherapy for carcinoma of the breast. Computed tomography was able to identify varying grades of abnormality that were ascribed to radiation fibrosis. Twenty-eight patients had neurological symptoms affecting the arm or hand on the treated side and CT changes were seen in 96%. The grading and significance of these CT abnormalities is discussed. The patients had been treated by two different radiotherapy techniques (three-field and four-field) which utilised either a large or small treatment fraction. The higher grades of abnormality on CT were seen in 57% of those treated with the large fraction size and 27% of those treated with the small fraction size. However, the changes on CT did not relate to the different radiotherapy techniques. 相似文献
1000.